U.S. patent application number 15/992422 was filed with the patent office on 2018-12-06 for methods and systems to form propylene chlorohydrin and propylene oxide.
The applicant listed for this patent is Calera Corporation. Invention is credited to Thomas A. Albrecht, Ryan J. Gilliam, Kyle Self, Michael Joseph Weiss.
Application Number | 20180347056 15/992422 |
Document ID | / |
Family ID | 64456156 |
Filed Date | 2018-12-06 |
United States Patent
Application |
20180347056 |
Kind Code |
A1 |
Self; Kyle ; et al. |
December 6, 2018 |
METHODS AND SYSTEMS TO FORM PROPYLENE CHLOROHYDRIN AND PROPYLENE
OXIDE
Abstract
There are provided methods and systems to form propylene
chlorohydrin by hydrolysis of 1,2-dichloropropane and to further
form propylene oxide from propylene chlorohydrin.
Inventors: |
Self; Kyle; (San Jose,
CA) ; Weiss; Michael Joseph; (Los Gatos, CA) ;
Gilliam; Ryan J.; (San Jose, CA) ; Albrecht; Thomas
A.; (Sunnyvale, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Calera Corporation |
Moss Landing |
CA |
US |
|
|
Family ID: |
64456156 |
Appl. No.: |
15/992422 |
Filed: |
May 30, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62596215 |
Dec 8, 2017 |
|
|
|
62531669 |
Jul 12, 2017 |
|
|
|
62512900 |
May 31, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C25B 1/26 20130101; C25B
11/041 20130101; C25B 3/06 20130101; C07C 29/64 20130101; C25B 3/02
20130101; C25B 11/04 20130101; C07C 29/86 20130101; C25B 1/24
20130101; C07C 17/02 20130101; C25B 15/08 20130101; C07C 29/124
20130101; C07C 29/86 20130101; C07C 31/36 20130101; C07C 29/124
20130101; C07C 31/36 20130101; C07C 29/64 20130101; C07C 31/36
20130101; C07C 17/02 20130101; C07C 19/01 20130101 |
International
Class: |
C25B 3/06 20060101
C25B003/06; C25B 3/02 20060101 C25B003/02; C25B 11/04 20060101
C25B011/04 |
Claims
1. A method to form propylene chlorohydrin (PCH), comprising: (i)
contacting an anode with an anode electrolyte in an electrochemical
cell wherein the anode electrolyte comprises metal chloride and
saltwater; contacting a cathode with a cathode electrolyte in the
electrochemical cell; applying voltage to the anode and the cathode
and oxidizing the metal chloride with metal ion in a lower
oxidation state to a higher oxidation state at the anode; (ii)
withdrawing the anode electrolyte from the electrochemical cell and
chlorinating propylene with the anode electrolyte comprising metal
chloride with metal ion in higher oxidation state and the saltwater
to result in one or more products comprising PCH and
1,2-dichloropropane (DCP), and the metal chloride with the metal
ion in lower oxidation state; (iii) extracting the one or more
products comprising PCH and DCP from aqueous medium by extracting
with DCP as an extraction solvent; and (iv) hydrolyzing the DCP
with water to form the PCH.
2. The method of claim 1, wherein the DCP as the extraction solvent
is the DCP separated and recirculated from the same process and/or
is DCP from other sources.
3. The method of claim 1, wherein amount of the DCP in the
hydrolysis is between about 10-95% by volume.
4. The method of claim 1, further comprising after extraction,
transferring aqueous medium comprising the metal chloride with
metal ions in the higher oxidation state and the lower oxidation
state to the oxychlorination reaction and oxidizing the metal ion
of the metal chloride from the lower oxidation state to the higher
oxidation state in presence of an oxidant.
5. The method of claim 4, wherein the oxidant is X.sub.2 gas alone;
or HX gas and/or HX solution in combination with gas comprising
oxygen or ozone; or hydrogen peroxide; or HXO or salt thereof; or
HXO.sub.3 or salt thereof; or HXO.sub.4 or salt thereof; or
combinations thereof, wherein each X independently is a halogen
selected from fluorine, chlorine, iodine, and bromine.
6. The method of claim 5, further comprising forming HCl by the
hydrolysis of the DCP to the PCH; separating the HCl; and
transferring the HCl to the oxychlorination reaction; and/or adding
other HCl to the oxychlorination reaction.
7. The method of claim 4, further comprising recirculating the
metal chloride with the metal ion in the higher oxidation state
back to the chlorination reaction and/or to the electrochemical
cell.
8. The method of claim 1, wherein the PCH is formed with
selectivity of between about 20-100% by wt and/or more than 0.01
STY.
9. The method of claim 1, further comprising after hydrolysis,
transferring organic medium comprising PCH and DCP to epoxidation;
and epoxidizing the PCH with a base to form PO in presence of the
DCP.
10. The method of claim 9, wherein the base is selected from alkali
metal hydroxide, alkali metal oxide, alkaline earth metal
hydroxide, alkaline earth metal oxide, or metal hydroxychloride
species of stoichiometry M.sub.x.sup.n+Cl.sub.y(OH).sub.(nx-y).
11. The method of claim 10, wherein the base is between about 5-38
wt %.
12. The method of claim 9, wherein the reaction forms between about
5-40 tonnes of brine per tonne of PO.
13. The method of claim 1, wherein the saltwater comprises alkali
metal chloride or alkaline earth metal chloride.
14. The method of claim 1, wherein metal ion in the metal chloride
is selected from the group consisting of iron, chromium, copper,
tin, silver, cobalt, uranium, lead, mercury, vanadium, bismuth,
titanium, ruthenium, osmium, europium, zinc, cadmium, gold, nickel,
palladium, platinum, rhodium, iridium, manganese, technetium,
rhenium, molybdenum, tungsten, niobium, tantalum, zirconium,
hafnium, and combination thereof.
15. The method of claim 1, wherein the metal chloride is copper
chloride.
16. The method of claim 9, further comprising adding other DCP to
the chlorination; to the hydrolysis; and/or to the epoxidation for
the extraction.
17. The method of claim 16, wherein the other DCP is obtained from
a traditional chlorohydrin process and/or from direct chlorination
of propylene with chlorine.
18. A system to form PO, comprising: (i) an electrochemical cell
comprising an anode chamber comprising an anode and an anode
electrolyte wherein the anode electrolyte comprises metal chloride
and saltwater and the anode is configured to oxidize the metal
chloride with metal ion in a lower oxidation state to a higher
oxidation state; a cathode chamber comprising a cathode and a
cathode electrolyte; and a voltage source configured to apply
voltage to the anode and the cathode; (ii) a chlorination reactor
operably connected to the anode chamber of the electrochemical cell
and configured to obtain the anode electrolyte and chlorinate
propylene with the anode electrolyte comprising the metal chloride
with the metal ion in the higher oxidation state in the saltwater
to result in one or more products comprising DCP and the metal
chloride with the metal ion in the lower oxidation state; (iii) a
hydrolysis reactor operably connected to the chlorination reactor
and configured to obtain the one or more products comprising DCP
from the chlorination reactor with or without the saltwater
comprising metal chloride and configured to hydrolyze the DCP to
PCH; and (iv) an epoxidation reactor operably connected to the
hydrolysis reactor and configured to obtain the solution comprising
DCP and PCH and epoxidize the PCH to PO in presence of a base.
19. The system of claim 18, further comprising an oxychlorination
reactor operably connected to the chlorination reactor and/or the
electrochemical cell; operably connected to the hydrolysis reactor;
and configured to obtain aqueous medium from the chlorination
reactor and/or the electrochemical cell comprising the metal
chloride with metal ion in the lower oxidation state and the higher
oxidation state; configured to obtain HCl produced in the
hydrolysis reactor; and configured to oxidize the metal chloride
with metal ion in the lower oxidation state to the higher oxidation
state using an oxidant comprising the HCl and oxygen, or hydrogen
peroxide.
20. The system of claim 18, further comprising the chlorination
reactor and/or the hydrolysis reactor operably connected to a
traditional chlorohydrin system and/or to another chlorination
reactor chlorinating propylene with chlorine, and configured to
obtain other DCP from the traditional chlorohydrin system and/or
from the another chlorination reactor chlorinating propylene with
chlorine.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional
Application No. 62/512,900, filed May 31, 2017; U.S. Provisional
Application No. 62/531,669, filed Jul. 12, 2017; and U.S.
Provisional Application No. 62/596,215, filed Dec. 8, 2017, all of
which are incorporated herein by reference in their entirety in the
present disclosure.
BACKGROUND
[0002] Polyurethane production remains one of the environmentally
challenging manufacturing processes in industrial polymerization.
Formed from addition reactions of di-isocyanates and polyols,
polyurethanes may have a significant embedded environmental
footprint because of the challenges associated with both
feedstocks. Polyols are themselves polymerization derivatives which
use propylene oxide as raw materials. Traditionally, propylene
oxide (PO) may be synthesized from a chlorinated intermediate,
propylene chlorohydrin. However, an environmentally acceptable
process for the economic production of propylene oxide remains
elusive. High costs of chlorine and significant waste water
production (approximately 40 tonnes of waste water per tonne of PO)
has caused manufacturers to look for process options with reduced
environmental and safety risks.
SUMMARY
[0003] Provided herein are environmentally friendly methods and
systems to produce propylene chlorohydrin (PCH) and propylene oxide
(PO) in high yields and high selectivity with significantly less
side products and/or waste materials.
[0004] In one aspect, there are provided methods to form PCH,
comprising:
[0005] (i) contacting an anode with an anode electrolyte in an
electrochemical cell wherein the anode electrolyte comprises metal
chloride and saltwater; contacting a cathode with a cathode
electrolyte in the electrochemical cell; applying voltage to the
anode and the cathode and oxidizing the metal chloride with metal
ion in a lower oxidation state to a higher oxidation state at the
anode;
[0006] (ii) withdrawing the anode electrolyte from the
electrochemical cell and chlorinating propylene with the anode
electrolyte comprising metal chloride with metal ion in higher
oxidation state and the saltwater to result in one or more products
comprising PCH and dichloropropane (DCP), and the metal chloride
with the metal ion in lower oxidation state;
[0007] (iii) separating the one or more products comprising PCH and
DCP from aqueous medium; and
[0008] (iv) hydrolyzing the DCP with water to form the PCH.
[0009] In one aspect, there are provided methods to form PCH,
comprising:
[0010] (i) oxidizing metal chloride with metal ion in a lower
oxidation state to a higher oxidation state in presence of an
oxidant in an oxychlorination reaction;
[0011] (ii) withdrawing the metal chloride with metal ion in the
higher oxidation state from the oxychlorination reaction and
chlorinating propylene with the metal chloride with the metal ion
in the higher oxidation state in saltwater under reaction
conditions to result in one or more products comprising PCH and
DCP, and the metal chloride with the metal ion in lower oxidation
state;
[0012] (iii) separating the one or more products comprising PCH and
DCP from aqueous medium; and
[0013] (iv) hydrolyzing the DCP with water to form the PCH.
[0014] In one aspect, there are provided methods to form PCH,
comprising:
[0015] (i) contacting an anode with an anode electrolyte in an
electrochemical cell wherein the anode electrolyte comprises metal
chloride and saltwater; contacting a cathode with a cathode
electrolyte in the electrochemical cell; applying voltage to the
anode and the cathode and oxidizing the metal chloride with metal
ion in a lower oxidation state to a higher oxidation state at the
anode;
[0016] (ii) withdrawing the anode electrolyte from the
electrochemical cell and chlorinating propylene with the anode
electrolyte comprising metal chloride with metal ion in higher
oxidation state and the saltwater to result in one or more products
comprising PCH and DCP, and the metal chloride with the metal ion
in lower oxidation state;
[0017] (iii) extracting the one or more products comprising PCH and
DCP from aqueous medium by extracting with DCP as an extraction
solvent; and
[0018] (iv) hydrolyzing the DCP with water to form the PCH.
[0019] In one aspect, there are provided methods to form PCH,
comprising:
[0020] (i) oxidizing metal chloride with metal ion in a lower
oxidation state to a higher oxidation state in presence of an
oxidant in an oxychlorination reaction;
[0021] (ii) withdrawing the metal chloride with metal ion in the
higher oxidation state from the oxychlorination reaction and
chlorinating propylene with the metal chloride with the metal ion
in the higher oxidation state in saltwater under reaction
conditions to result in one or more products comprising PCH and
DCP, and the metal chloride with the metal ion in lower oxidation
state;
[0022] (iii) extracting the one or more products comprising PCH and
DCP from aqueous medium by extracting with DCP as an extraction
solvent; and
[0023] (iv) hydrolyzing the DCP with water to form the PCH.
[0024] In some embodiments of the foregoing aspect, the DCP as the
extraction solvent is the DCP separated and recirculated from the
same process and/or is DCP from other sources.
[0025] In some embodiments of the foregoing aspects and embodiment,
the amount of the DCP in the hydrolysis is between about 10-95% by
volume.
[0026] In some embodiments of the foregoing aspects and
embodiments, the hydrolysis is catalyzed by presence of a nobel
metal selected from ruthenium, rhodium, palladium, silver, osmium,
iridium, platinum, gold, mercury, rhenium, titanium, niobium,
tantalum, and combinations thereof.
[0027] In some embodiments of the foregoing aspects and
embodiments, the hydrolysis is carried out in presence of metal
hydroxychloride species of stoichiometry
M.sub.x.sup.n+Cl.sub.y(OH).sub.(nx-y), such as, for example only,
Cu.sub.xCl.sub.y(OH).sub.(2x-y).
[0028] In some embodiments of the foregoing aspects and
embodiments, the method further comprises after extraction,
transferring aqueous medium comprising the metal chloride with
metal ions in the higher oxidation state and the lower oxidation
state to the oxychlorination reaction and oxidizing the metal ion
of the metal chloride from the lower oxidation state to the higher
oxidation state in presence of the oxidant. In some embodiments of
the foregoing aspects and embodiments, the oxidant is HCl and
oxygen or hydrogen peroxide (or any other oxidant as described
herein). In some embodiments of the foregoing aspects and
embodiments, the method further comprises forming HCl by the
hydrolysis of the DCP to the PCH; separating the HCl; and
transferring the HCl to the oxychlorination reaction; and/or adding
other HCl to the oxychlorination reaction. The "other HCl" has been
described herein. In some embodiments of the foregoing aspects and
embodiments, the method further comprises recirculating the metal
chloride with the metal ion in the higher oxidation state back to
the chlorination reaction and/or the electrochemical reaction.
[0029] In some embodiments of the foregoing aspects and
embodiments, the method further comprises after extraction,
transferring aqueous medium comprising the metal chloride with
metal ion in the higher oxidation state and the lower oxidation
state to the hydrolysis reaction.
[0030] In some embodiments of the foregoing aspects and
embodiments, the PCH is formed with selectivity of between about
20-100% by wt and/or more than 0.01 STY.
[0031] In some embodiments of the foregoing aspects and
embodiments, the method further comprises after hydrolysis,
transferring organic medium comprising PCH and DCP to epoxidation;
and epoxidizing the PCH with a base to form PO in presence of the
DCP. In some embodiments of the foregoing aspects and embodiments,
the base is selected from alkali metal hydroxide, alkali metal
oxide, alkaline earth metal hydroxide, or alkaline earth metal
oxide. In some embodiments of the foregoing aspects and
embodiments, the base is a metal hydroxychloride species, such as
copper hydroxychloride species of stoichiometry
Cu.sub.xCl.sub.y(OH).sub.(2x-y). In some embodiments of the
foregoing aspects and embodiments, metal in the metal
hydroxychloride is same as metal in the metal chloride. In some
embodiments of the foregoing aspects and embodiments, the method
further comprises forming the metal hydroxychloride by
oxychlorinating the metal chloride with the metal ion in the lower
oxidation state to the higher oxidation state in presence of water
and oxygen. In some embodiments of the foregoing aspects and
embodiments, the base is between about 5-38 wt %.
[0032] In some embodiments of the foregoing aspects and
embodiments, the reaction forms between about 5-42 or 5-40 tonnes
of brine per tonne of PO.
[0033] In some embodiments of the foregoing aspects and
embodiments, the saltwater comprises alkali metal chloride or
alkaline earth metal chloride.
[0034] In some embodiments of the foregoing aspects and
embodiments, metal ion in the metal chloride is selected from the
group consisting of iron, chromium, copper, tin, silver, cobalt,
uranium, lead, mercury, vanadium, bismuth, titanium, ruthenium,
osmium, europium, zinc, cadmium, gold, nickel, palladium, platinum,
rhodium, iridium, manganese, technetium, rhenium, molybdenum,
tungsten, niobium, tantalum, zirconium, hafnium, and combination
thereof.
[0035] In some embodiments of the foregoing aspects and
embodiments, the metal chloride is copper chloride.
[0036] In some embodiments of the foregoing aspects and
embodiments, the method further comprises adding other DCP to the
chlorination; to the hydrolysis; and/or to the epoxidation for the
extraction. In some embodiments of the foregoing aspects and
embodiments, the other DCP is obtained from a traditional
chlorohydrin process and/or from direct chlorination of propylene
with chlorine.
[0037] In some embodiments of the foregoing aspects and
embodiments, the one or more products further comprise isopropanol
and/or isopropyl chloride. In some embodiments of the foregoing
aspects and embodiments, the method further comprises converting
the isopropanol and/or the isopropyl chloride back to the
propylene, DCP, and/or PCH.
[0038] In one aspect, there are provided systems to form PO,
comprising:
[0039] (i) an electrochemical cell comprising an anode chamber
comprising an anode and an anode electrolyte wherein the anode
electrolyte comprises metal chloride and saltwater and the anode is
configured to oxidize the metal chloride with metal ion in a lower
oxidation state to a higher oxidation state; a cathode chamber
comprising a cathode and a cathode electrolyte; and a voltage
source configured to apply voltage to the anode and the
cathode;
[0040] (ii) a chlorination reactor operably connected to the anode
chamber of the electrochemical cell and configured to obtain the
anode electrolyte and chlorinate propylene with the anode
electrolyte comprising the metal chloride with the metal ion in the
higher oxidation state in the saltwater to result in one or more
products comprising DCP and the metal chloride with the metal ion
in the lower oxidation state;
[0041] (iii) a hydrolysis reactor operably connected to the
chlorination reactor and configured to obtain the one or more
products comprising DCP from the chlorination reactor with or
without the saltwater comprising metal chloride and configured to
hydrolyze the DCP to PCH; and
[0042] (iv) an epoxidation reactor operably connected to the
hydrolysis reactor and configured to obtain the solution comprising
DCP and PCH and epoxidize the PCH to PO in presence of a base.
[0043] In one aspect, there are provided systems to form PO,
comprising:
[0044] (i) an oxychlorination reactor configured to oxidize metal
chloride with metal ion in lower oxidation state to higher
oxidation state using an oxidant (oxidants have been described
herein);
[0045] (ii) a chlorination reactor operably connected to the
oxychlorination reactor and configured to obtain the metal chloride
with the metal ion in the higher oxidation state and chlorinate
propylene with the metal chloride with the metal ion in the higher
oxidation state in the saltwater to result in one or more products
comprising DCP and the metal chloride with the metal ion in the
lower oxidation state;
[0046] (iii) a hydrolysis reactor operably connected to the
chlorination reactor and configured to obtain the one or more
products comprising DCP from the chlorination reactor with or
without the saltwater comprising metal chloride and configured to
hydrolyze the DCP to PCH; and
[0047] (iv) an epoxidation reactor operably connected to the
hydrolysis reactor and configured to obtain the solution comprising
DCP and PCH and epoxidize the PCH to PO in presence of a base.
[0048] In one aspect, there are provided systems to form PO,
comprising:
[0049] (i) a chlorination reactor configured to chlorinate
propylene with chlorine to result in one or more products
comprising DCP;
[0050] (ii) a hydrolysis reactor operably connected to the
chlorination reactor and configured to obtain the one or more
products comprising DCP from the chlorination reactor and
configured to hydrolyze the DCP to PCH; and
[0051] (iii) an epoxidation reactor operably connected to the
hydrolysis reactor and configured to obtain the solution comprising
DCP and PCH and epoxidize the PCH to PO in presence of a base.
[0052] In some embodiments of the foregoing aspects and
embodiments, the system further comprises an oxychlorination
reactor
[0053] operably connected to the chlorination reactor and/or the
electrochemical cell;
[0054] operably connected to the hydrolysis reactor; and
[0055] configured to obtain aqueous medium from the chlorination
reactor and/or the electrochemical cell comprising the metal
chloride with metal ion in the lower oxidation state and the higher
oxidation state;
[0056] configured to obtain HCl produced in the hydrolysis reactor;
and
[0057] configured to oxidize the metal chloride with metal ion in
the lower oxidation state to the higher oxidation state using an
oxidant comprising the HCl and oxygen, or hydrogen peroxide (or any
other oxidant known in the art).
[0058] In some embodiments of the foregoing aspect and embodiments,
the system further comprises the chlorination reactor and/or the
hydrolysis reactor operably connected to a traditional chlorohydrin
system and/or to another chlorination reactor chlorinating
propylene with chlorine, and configured to obtain other DCP from
the traditional chlorohydrin system and/or from the another
chlorination reactor chlorinating propylene with chlorine.
[0059] In one aspect, there is provided a method to form propylene
chlorohydrin (PCH), comprising: chlorinating propylene in an
aqueous medium comprising metal chloride with metal ion in higher
oxidation state and salt to result in one or more products
comprising propylene chlorohydrin (PCH), and the metal chloride
with the metal ion in lower oxidation state. In some embodiments of
the foregoing aspect, the one or more products further comprise
1,2-dichloropropane (DCP). In some embodiments of the foregoing
aspect and embodiment, the method further comprises separating DCP
from the aqueous medium and converting the DCP to the PCH. In some
embodiments of the foregoing aspect and embodiment, the method
further comprises hydrolyzing the DCP to the PCH in situ.
[0060] In some embodiments of the foregoing aspect and embodiments,
the method further comprises adding platinum or palladium to the
aqueous medium to form PCH in yield of between about 10-100%. In
some embodiments of the foregoing aspect and embodiments, the
platinum or palladium is in concentration of between about
0.001-0.1M.
[0061] In some embodiments of the foregoing aspect and embodiments,
the method further comprises chlorinating propylene in presence of
oxygen.
[0062] In some embodiments of the foregoing aspect and embodiments,
reaction conditions for the chlorination reaction comprise
temperature between 20-150.degree. C., pressure between 125-350
psig, or combination thereof.
[0063] In some embodiments of the foregoing aspect and embodiments,
the one or more products further comprise isopropanol and/or
isopropyl chloride. In some embodiments of the foregoing aspect and
embodiment, the method further comprises converting the isopropanol
and/or the isopropyl chloride back to the propylene.
[0064] In some embodiments of the foregoing aspect and embodiments,
the one or more products further comprise hydrochloric acid (HCl).
In some embodiments of the foregoing aspect and embodiment, the
method further comprises after the chlorinating step,
oxychlorinating the metal chloride with the metal ion in the lower
oxidation state to the metal ion in the higher oxidation state in
presence of the HCl and oxygen.
[0065] In some embodiments of the foregoing aspect and embodiment,
the method further comprises recirculating the metal chloride in
the higher oxidation state back to the chlorinating step.
[0066] In some embodiments of the foregoing aspect and embodiment,
the method further comprises reacting the PCH with a base to form
propylene oxide (PO). In some embodiments of the foregoing aspect
and embodiments, the base is an alkali metal or alkaline earth
metal hydroxide. In some embodiments of the foregoing aspect and
embodiments, the base is metal hydroxychloride. In some embodiments
of the foregoing aspect and embodiments, metal in the metal
hydroxychloride is same as metal in the metal chloride. In some
embodiments of the foregoing aspect and embodiment, the method
further comprises forming the metal hydroxychloride by
oxychlorinating the metal chloride with the metal ion in the lower
oxidation state to the higher oxidation state in presence of water
and oxygen.
[0067] In some embodiments of the foregoing aspect and embodiments,
the reaction further forms brine in water. In some embodiments of
the foregoing aspect and embodiments, the reaction forms between
about 5-45 or 5-42 tonnes of brine per tonne of PO.
[0068] In one aspect, there is provided a method to form propylene
oxide (PO), comprising chlorinating propylene in an aqueous medium
comprising metal chloride with metal ion in higher oxidation state
and salt to result in one or more products comprising between about
5-99.9 wt % propylene chlorohydrin (PCH), and the metal chloride
with the metal ion in lower oxidation state; and reacting the PCH
with a base to form propylene oxide (PO) and brine in water,
wherein the reaction forms between about 5-45 or 5-42 or 5-40
tonnes of brine per tonne of PO. In some embodiments of the
foregoing aspect, the base is between about 5-38 wt % or between
about 5-35 wt % or between about 8-15 wt % sodium hydroxide or
calcium hydroxide or calcium oxide (or any other base as described
herein).
[0069] In some embodiments of the foregoing aspects and embodiment,
the method further comprises transferring the aqueous medium
comprising the metal chloride with the metal ion in the lower
oxidation state and the salt to an anode electrolyte in contact
with an anode in an electrochemical cell and oxidizing the metal
ion from the lower oxidation state to the higher oxidation state at
the anode.
[0070] In some embodiments of the foregoing aspects and embodiment,
the method further comprises transferring the aqueous medium
comprising the metal chloride with the metal ion in the lower
oxidation state and the salt to an oxychlorination reaction and
oxidizing the metal ion from the lower oxidation state to the
higher oxidation state in the presence of HCl and oxygen.
[0071] In some embodiments of the foregoing aspects and
embodiments, the salt comprises alkali metal chloride or alkaline
earth metal chloride.
[0072] In some embodiments of the foregoing aspects and
embodiments, total amount of chloride content in the aqueous medium
is between 3-15M or between 3-5M or between 3-4M.
[0073] In some embodiments of the foregoing aspects and
embodiments, salt comprises sodium chloride, and the metal chloride
in the higher oxidation state is in range of 0.1-8M or between
about 0.1-3 or between about 0.1-2.5M, the metal chloride in the
lower oxidation state is in range of 0.1-2M and the sodium chloride
is in range of 0.1-5M or between about 0.1-3M.
[0074] In some embodiments of the foregoing aspects and
embodiments, metal ion in the metal chloride is selected from the
group consisting of iron, chromium, copper, tin, silver, cobalt,
uranium, lead, mercury, vanadium, bismuth, titanium, ruthenium,
osmium, europium, zinc, cadmium, gold, nickel, palladium, platinum,
rhodium, iridium, manganese, technetium, rhenium, molybdenum,
tungsten, niobium, tantalum, zirconium, hafnium, and combination
thereof.
[0075] In some embodiments of the foregoing aspects and
embodiments, the metal chloride is copper chloride.
[0076] In one aspect, there are provided systems, comprising
reactors configured to carry out the reactions of the preceding
aspects and embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0077] The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the present invention may be obtained by
reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the invention
are utilized, and the accompanying drawings of which:
[0078] FIG. 1A is an illustration of some embodiments related to
the methods and systems provided herein to form the PCH and the
PO.
[0079] FIG. 1B is an illustration of some embodiments related to
the methods and systems provided herein to form the PCH and the
PO.
[0080] FIG. 2 is an illustration of some embodiments related to the
formation of products from chlorination of propylene.
[0081] FIG. 3 is an illustration of some embodiments related to the
methods and systems provided herein to form the PCH and the PO.
[0082] FIG. 4 is an illustration of some embodiments related to the
methods and systems provided herein to form the PCH and the PO.
[0083] FIG. 5 is an illustration of some embodiments related to the
methods and systems provided herein to form the PCH and the PO.
DETAILED DESCRIPTION
[0084] Disclosed herein are systems and methods that relate to
producing propylene chlorohydrin and further propylene oxide in
high yields with significantly less side products and/or waste
materials.
[0085] Before the present invention is described in greater detail,
it is to be understood that this invention is not limited to
particular embodiments described, as such may, of course, vary. It
is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting.
[0086] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limit of that range and any other stated or intervening
value in that stated range, is encompassed within the invention.
The upper and lower limits of these smaller ranges may
independently be included in the smaller ranges and are also
encompassed within the invention, subject to any specifically
excluded limit in the stated range. Where the stated range includes
one or both of the limits, ranges excluding either or both of those
included limits are also included in the invention.
[0087] Certain ranges that are presented herein with numerical
values may be construed as "about" numericals. The "about" is to
provide literal support for the exact number that it precedes, as
well as a number that is near to or approximately the number that
the term precedes. In determining whether a number is near to or
approximately a specifically recited number, the near or
approximating unrequited number may be a number, which, in the
context in which it is presented, provides the substantial
equivalent of the specifically recited number.
[0088] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can also be used in the practice or testing of the present
invention, representative illustrative methods and materials are
now described.
[0089] All publications and patents cited in this specification are
herein incorporated by reference as if each individual publication
or patent were specifically and individually indicated to be
incorporated by reference and are incorporated herein by reference
to disclose and describe the methods and/or materials in connection
with which the publications are cited.
[0090] It is noted that, as used herein and in the appended claims,
the singular forms "a," "an," and "the" include plural references
unless the context clearly dictates otherwise. It is further noted
that the claims may be drafted to exclude any optional element. As
such, this statement is intended to serve as antecedent basis for
use of such exclusive terminology as "solely," "only" and the like
in connection with the recitation of claim elements, or use of a
"negative" limitation.
[0091] As will be apparent to those of skill in the art upon
reading this disclosure, each of the individual embodiments
described and illustrated herein has discrete components and
features which may be readily separated from or combined with the
features of any of the other several embodiments without departing
from the scope or spirit of the present invention. Any recited
method can be carried out in the order of events recited or in any
other order which is logically possible.
Methods and Systems
[0092] There are provided methods and systems that relate to the
chlorination of propylene for the generation of one or more
products comprising dichloropropane or 1,2-dichloropropane (DCP)
and/or propylene chlorohydrin (PCH); hydrolysis of the DCP to the
PCH; and further reaction of the PCH to form propylene oxide (PO).
In some embodiments the chlorination is done using metal chloride
solution with metal ions in higher oxidation state. There are also
provided methods and systems for separation/purification of the
products from the metal ion solution; regeneration of the metal
chloride with metal ions in the higher oxidation state; recycling
of the metal ion solution back to the chlorination reaction; and
recycling of other side products.
[0093] Applicants have devised methods and systems to form the PCH
and/or DCP in high yields and high selectivity where either the
side products are not formed, or are formed in low yields, or are
converted to the PCH, DCP, and/or propylene. Applicants have also
devised methods and systems to convert the side products back
either to the propylene or to the PCH such that the PCH is formed
in high yield and with selectivity. Further Applicants have devised
methods and systems to form the PO from the PCH in high yield and
with high selectivity. Applicants have devised methods and systems
to form the PO with reduced waste water, resulting in economical
and environmentally friendly methods to form the PO.
[0094] The combination of methods and systems used to form the PCH
from the propylene and further to form the PO relate to various
combinations of an electrochemical method/system, a chlorination
method/system, an oxychlorination method/system, a hydrolysis
method/system, and an epoxidation method/system, to form the PO.
The electrochemical and the chlorination methods and systems have
been described in detail in U.S. patent application Ser. No.
13/474,598, filed May 17, 2012, issued as U.S. Pat. No. 9,187,834,
on Nov. 17, 2015, which is incorporated herein by reference in its
entirety. The oxychlorination and the epoxidation methods and
systems have been described in U.S. patent application Ser. No.
15/963,637, filed Apr. 26, 2018, which is incorporated herein by
reference in its entirety.
[0095] Illustrated in FIG. 1A is the block flow diagram for the
formation of the PO from the propylene. In block 3, is shown an
electrochemical reaction/cell where the metal ions of the metal
halide in the lower oxidation state and the higher oxidation state
are illustrated as CuCl (a mixture of CuCl and CuCl.sub.2). Metal
ions are oxidized from the lower oxidation state to the higher
oxidation state at the anode where cathode reaction includes
formation of sodium hydroxide. Other cathode reaction are also
possible and are explained in detail in U.S. patent application
Ser. No. 15/963,637, filed Apr. 26, 2018, which is incorporated
herein by reference in its entirety. For example, in some
embodiments, the cathode electrolyte comprises water and the
cathode is an oxygen depolarizing cathode that reduces oxygen and
water to hydroxide ions; the cathode electrolyte comprises water
and the cathode is a hydrogen gas producing cathode that reduces
water to hydrogen gas and hydroxide ions; the cathode electrolyte
comprises hydrochloric acid and the cathode is a hydrogen gas
producing cathode that reduces hydrochloric acid to hydrogen gas;
or the cathode electrolyte comprises hydrochloric acid and the
cathode is an oxygen depolarizing cathode that reacts hydrochloric
acid and oxygen gas to form water.
[0096] The "metal ion" or "metal" or "metal ion in the metal
chloride" or "metal ion in the metal halide" as used herein,
includes any metal ion capable of being converted from lower
oxidation state to higher oxidation state and vice versa. Examples
of metal ions in the metal halide include, but are not limited to,
iron, chromium, copper, tin, silver, cobalt, uranium, lead,
mercury, vanadium, bismuth, titanium, ruthenium, osmium, europium,
zinc, cadmium, gold, nickel, palladium, platinum, rhodium, iridium,
manganese, technetium, rhenium, molybdenum, tungsten, niobium,
tantalum, zirconium, hafnium, and combination thereof. In some
embodiments, the metal ions include, but are not limited to, iron,
copper, tin, chromium, or combination thereof. In some embodiments,
the metal ion is copper. In some embodiments, the metal ion is tin.
In some embodiments, the metal ion is iron. In some embodiments,
the metal ion is chromium. In some embodiments, the metal ion is
platinum. The "oxidation state" as used herein, includes degree of
oxidation of an atom in a substance. For example, in some
embodiments, the oxidation state is the net charge on the metal
ion. The "halide" as used herein, includes fluoride, bromide,
chloride, and iodide. For example only, metal halide includes metal
chlorides such as, but not limited to, copper chloride (CuCl with
Cu in the lower oxidation state of 1 and CuCl.sub.2 with Cu in the
higher oxidation state of 2).
[0097] As used herein, the "salt" or "saltwater" includes salt or
salt in water where salt can be any alkali metal chloride or
alkaline earth metal chloride, including but not limited to, sodium
chloride, potassium chloride, lithium chloride, calcium chloride,
magnesium chloride etc.
[0098] It is to be understood that the metal chloride with the
metal ion in the lower oxidation state and the metal chloride with
the metal ion in the higher oxidation state are both present in the
aqueous medium in the electrochemical reaction/cell and the
chlorination reaction/reactor. Owing to the reduction of the metal
chloride from the higher oxidation state to the lower oxidation
state in the chlorination reaction, the ratio of the metal chloride
in the lower and the higher oxidation state are different in the
aqueous medium entering the chlorination reaction and exiting the
chlorination reaction. Suitable concentrations of the metal ions in
the lower and higher oxidation state in the aqueous medium have
been described herein. Some examples of the metal chlorides that
may be used in the systems and methods include, but are not limited
to, copper chloride, iron chloride, tin chloride, chromium
chloride, zinc chloride, etc.
[0099] The anolyte from the anode chamber containing an aqueous
stream of sodium chloride (any other salt may be used including but
not limited to, alkali metal chloride such as potassium chloride or
alkaline earth metal chloride such as calcium chloride), water and
CuCl is then transferred to the chlorination reaction/reactor shown
in block 1. In block 1, the propylene C.sub.3H.sub.6 is converted
into the DCP and/or the PCH using copper chloride (II),
simultaneously reducing two Cu(II) ions to Cu(I). The reactions are
as shown below:
C.sub.3H.sub.6+2CuCl.sub.2.fwdarw.ClCH.sub.2CH(Cl)CH.sub.3(DCP)+2CuCl
(I)
C.sub.3H.sub.6+2CuCl.sub.2+H.sub.2O.fwdarw.ClCH.sub.2CH(OH)CH.sub.3(PCH)-
+2CuCl+HCl (II)
[0100] The "propylene chlorohydrin" or "PCH", as used herein
includes PCH in its isomeric form, such as, 1-chloro-2-propanol,
2-chloro-1-propanol, or both. Without being limited by any theory,
both isomers may be formed and both may be subsequently converted
to the PO. The explicit declaration of one isomer may not be
construed as the absence of the other.
[0101] In block 2, some of the Cu(I) produced in block 1 is
regenerated using chemical oxidation in oxychlorination
reaction/reactor using oxidants such as, but not limited to,
X.sub.2 gas alone; or HX gas and/or HX solution in combination with
gas comprising oxygen or ozone; or hydrogen peroxide; or HXO or
salt thereof; or HXO.sub.3 or salt thereof; or HXO.sub.4 or salt
thereof; or combinations thereof, wherein each X independently is a
halogen selected from fluorine, chlorine, iodine, and bromine. For
example, chlorine gas may be used to oxidize the metal halide from
the lower to the higher oxidation state. For example, CuCl may be
oxidized to CuCl.sub.2 in the presence of chlorine gas as
follows:
2CuCl+Cl.sub.2.fwdarw.2CuCl.sub.2 (III)
[0102] In some embodiments, the oxidant is HCl gas and/or HCl
solution in combination with gas comprising oxygen. An example is
as follows:
2CuCl+2HCl+1/2O.sub.2.fwdarw.2CuCl.sub.2+H.sub.2O (IV)
[0103] In some embodiments, the oxidant is HX gas and/or HX
solution in combination with hydrogen peroxide, wherein X is a
halogen. One example is as follows:
2CuCl+H.sub.2O.sub.2+2HCl.fwdarw.2CuCl.sub.2+2H.sub.2O (V)
[0104] The oxidants have been described in U.S. patent application
Ser. No. 15/963,637, filed Apr. 26, 2018, which is incorporated
herein by reference in its entirety. Hydrochloric acid (HCl) is a
common by-product in numerous chemical processes. One side product
of the chlorination reaction of the propylene to the PCH is also
HCl. The methods and systems provided herein can leverage the HCl
in the oxychlorination step as a mechanism to provide additional
copper oxidation. The HCl can also be sourced from other reactions
and is labeled as "other HCl" in figures. The incorporation of HCl
from chlorination reaction or other reactions may lead to
additional PO production by upgrading these streams to more
valuable products. The reuse of the HCl in oxychlorination process
allows for the reduction of the base consumption to neutralize the
acid which may improve overall economics, especially in cases where
the base could otherwise be sold.
[0105] It is to be understood that the processes illustrated in
FIG. 1A, such as electrochemical reaction, chlorination reaction,
and the oxychlorination reaction, may each be individually carried
out or may be in combination with one or more other processes. For
example, the electrochemically generated CuCl.sub.2 may be used in
one reactor for the chlorination of the propylene to the PCH and/or
the DCP and the chemically generated CuCl.sub.2 (via
oxychlorination) may be used in another propylene chlorination
reactor each with the option of making the PCH directly or making
the DCP with subsequent conversion to the PCH, all such
configurations are within the scope of the present disclosure.
[0106] In one aspect, the oxychlorination reaction/reactor oxidizes
the metal ion of the metal chloride in the lower oxidation state to
the higher oxidation state in the presence of the oxidant (and in
the absence of any electrochemical reaction/cell) and then the
metal chloride with the metal ion in the higher oxidation state is
then transferred to the chlorination reaction/reactor to chlorinate
propylene, as illustrated in FIG. 1B. In block 2, is shown an
oxychlorination reaction/reactor where the metal ions of the metal
halide in the lower oxidation state and the higher oxidation state
are illustrated as CuCl (a mixture of CuCl and CuCl.sub.2). Metal
ions are oxidized from the lower oxidation state to the higher
oxidation state in the oxychlorination reaction/reactor. The
solution from the oxychlorination reaction/reactor containing
CuCl.sub.x is then transferred to the chlorination reaction/reactor
shown in block 1. In block 1, the propylene C.sub.3H.sub.6 is
converted into the DCP and/or the PCH using copper chloride (II),
simultaneously reducing two Cu(II) ions to Cu(I). It is to be
understood that the electrochemical reaction/cell and the
oxychlorination reaction/reactor may independently be carried out
for the oxidation of the metal chloride (such as FIG. 1B for the
oxychlorination reaction/reactor) or may be carried out in
combination (such as FIG. 1A).
[0107] As shown in FIG. 1A, additional oxidation of the metal ion
from the lower oxidation state to the higher oxidation state, e.g.
CuCl to CuCl.sub.2, may be done electrochemically in block 3.
Overall, the oxidation done in blocks 2 and 3 may equal the amount
of reduction accomplished in 1. The flow of copper chloride between
the electrochemical, chlorination, and the oxychlorination systems
may be either clockwise or counter clockwise as indicated by the
circular arrows. That is, the order of operations between the three
units is flexible. The propylene chlorohydrin formed in 1 is
converted to propylene oxide in the epoxidation reaction/reactor
shown as block 4. The reaction is as shown below:
ClCH.sub.2CH(OH)CH.sub.3+NaOH.fwdarw.H.sub.2C(O)CHCH.sub.3(PO)+NaCl+H.su-
b.2O (VI)
[0108] In order to improve the yield and selectivity (or space time
yield (STY)) of the PO, it is essential to form the PCH with high
yield and high selectivity. The methods and system herein provide
various ways to form the PCH with high yield and high selectivity
and to subsequently also form the PO with high yield and high
selectivity.
Forming the PCH Under Reaction Conditions
[0109] In one aspect, there are provided methods that include
chlorinating propylene in an aqueous medium comprising metal
chloride with metal ion in higher oxidation state and salt under
reaction conditions to result in one or more products comprising
PCH, and the metal chloride with the metal ion in lower oxidation
state. The chlorination reaction may take place after the
electrochemical reaction and/or the oxychlorination reaction.
[0110] In some embodiments, there are provided methods that include
(i) contacting an anode with an anode electrolyte in an
electrochemical cell wherein the anode electrolyte comprises metal
chloride and saltwater; contacting a cathode with a cathode
electrolyte in the electrochemical cell; applying voltage to the
anode and the cathode and oxidizing the metal chloride with metal
ion in a lower oxidation state to a higher oxidation state at the
anode; and (ii) withdrawing the anode electrolyte from the
electrochemical cell and chlorinating propylene with the anode
electrolyte comprising the metal chloride with the metal ion in the
higher oxidation state in the saltwater under reaction conditions
to result in one or more products comprising PCH and the metal
chloride with the metal ion in the lower oxidation state.
[0111] In some embodiments, there are provided methods that include
(i) oxidizing metal chloride with metal ion in a lower oxidation
state to a higher oxidation state in presence of an oxidant in an
oxychlorination reaction; and (ii) withdrawing the metal chloride
with metal ion in the higher oxidation state from the
oxychlorination reaction and chlorinating propylene with the metal
chloride with the metal ion in the higher oxidation state in
saltwater under reaction conditions to result in one or more
products comprising PCH and the metal chloride with the metal ion
in the lower oxidation state.
[0112] In some embodiments of the aforementioned aspect and
embodiments, the methods further include (iii) epoxidizing the PCH
with a base to form PO.
[0113] An illustration of the chlorination reaction is shown in
FIG. 2. In some embodiments, the propylene may be supplied under
pressure in the liquid phase and/or the gas phase and the metal
chloride, for example only, copper (II) chloride (also containing
copper (I) chloride) is supplied in an aqueous solution such as
saltwater. The reaction may occur in the liquid phase where the
dissolved propylene reacts with the copper (II) chloride. As
illustrated in FIG. 2, the chlorination of the propylene in the
presence of the metal chloride with the metal ion in the higher
oxidation state (e.g. CuCl.sub.2) may result in one or more
products such as, but not limited to, PCH, DCP, isopropanol, and
isopropyl chloride. Applicants have found that in order to form the
PCH in high space time yield (to minimize reactor costs) with high
selectivity (to minimize propylene costs) certain reactions
conditions may be controlled and used. Such reaction conditions
include, but are not limited to, temperature and pressure in the
chlorination reaction; use of the other DCP; use of metal
hydroxychloride; amount of salt; amount of total chloride content;
residence time of the chlorination mixture; presence of a noble
metal; etc.
[0114] In some embodiments of all of the aforementioned aspect and
embodiments, the PCH is formed with selectivity of between about
20-100%; or between about 20-90%; or between about 20-80%; or
between about 20-70%; or between about 20-60%; or between about
20-50%; or between about 20-40%; or between about 30-100%; or
between about 30-90%; or between about 30-80%; or between about
30-70%; or between about 30-60%; or between about 30-50%; or
between about 30-40%; or between about 40-100%; or between about
40-90%; or between about 40-80%; or between about 40-70%; or
between about 40-60%; or between about 40-50%; or between about
75-100%; or between about 75-90%; or between about 75-80%; or
between about 90-100%; or between about 90-99%; or between about
90-95%. In some embodiments, the above noted selectivity is in wt
%.
[0115] In some embodiments, the STY (space time yield) of the one
or more products from propylene and/or DCP, e.g. the STY of PCH is
0.01, or 0.05, or less than 0.1, or more than 0.1, or more than
0.5, or is 1, or more than 1, or more than 2, or more than 3, or
more than 4, or between 0.01-0.05, or between 0.01-0.1, or between
0.1-3, or between 0.5-3, or between 0.5-2, or between 0.5-1, or
between 3-5. As used herein the STY is yield per time unit per
reactor volume. For example, the yield of product may be expressed
in mol, the time unit in hour and the volume in liter. The volume
may be the nominal volume of the reactor, e.g. in a packed bed
reactor, the volume of the vessel that holds the packed bed is the
volume of the reactor. The STY may also be expressed as STY based
on the amount of propylene consumed and/or based on amount of the
DCP consumed to form the product. For example only, in some
embodiments, the STY of the PCH product may be deduced from the
amount of propylene consumed and/or based on amount of the DCP
consumed during the reaction. The selectivity may be the mol of
product, e.g. PCH/mol of the propylene consumed and/or PCH/mol of
the DCP consumed. The yield may be the amount of the product
isolated. The purity may be the amount of the product/total amount
of all products (e.g., amount of PCH/all the organic products
formed).
[0116] Various suitable reaction conditions to form PCH have been
described herein below.
[0117] The "other DCP" or "other sources of DCP" as mentioned
herein (and illustrated in figures) includes DCP formed as a
by-product of other processes. Examples of the other processes or
sources include, but are not limited to, the traditional
chlorohydrin route to the PO or the DCP formed by the chlorination
of the propylene with chlorine. This stream is labeled as "other
DCP" in figures, which illustrates the various locations in the
process where this stream may be incorporated into the process. The
incorporation of this other DCP can lead to additional PCH and PO
production by upgrading these streams to more valuable
products.
[0118] In the traditional chlorohydrin process, the PCH may be
formed through the addition of hypochlorous acid (HOCl) to the
propylene. The HOCl may itself be formed by the addition of
chlorine (Cl.sub.2) to water, a reaction which co-produces a
stoichiometric amount of hydrochloric acid (HCl). To minimize
reactions of the propylene with both HCl and the direct addition of
Cl.sub.2 across the double bond, the reactor may be operated under
very dilute concentrations of HOCl and with an equivalent of base
(in the form of NaOH or CaO) to neutralize the HCl. Even under
these conditions, the formation of unwanted DCP can be significant,
representing a propylene selectivity loss on the order of 10%. This
unwanted DCP can be used as the other DCP in the methods described
herein and provide an economic use of a waste stream.
[0119] Another source of DCP (the "other DCP") is the production of
the DCP through the direct addition of chlorine to the propylene.
New or existing sources of chlorine (such as, but not limited to,
Deacon process and the chlor-alkali process) may be used to make
the DCP via direct chlorination of the propylene, similar to the
process used industrially to make ethylene dichloride from ethylene
and chlorine. This DCP formed via direct chlorination may then be
converted to the PCH using methods provided herein and ultimately
form the PO. The HCl formed as a by-product from the conversion to
the PCH would then be captured and reused.
[0120] Such methods and systems for other sources of DCP may be
integrated with the methods and systems provided herein to
hydrolyze the DCP formed as a major product or as a waste stream to
the PCH and then to the PO.
[0121] In some embodiments of the foregoing aspect and embodiments,
reaction conditions for the chlorination reaction comprise
temperature between 100-150.degree. C., pressure between 125-350
psig, or combination thereof.
[0122] In some embodiments of the aforementioned aspect and
embodiments, the methods to form PCH comprise reaction conditions,
such as, but not limited to, use of metal hydroxychloride. Without
being limited by any theory, it is contemplated that the metal
chloride may react with water and oxygen to form metal
hydroxychloride species of stoichiometry
M.sub.x.sup.n+Cl.sub.y(OH).sub.(nx-y),
M.sub.xCl.sub.y(OH).sub.(2x-y), M.sub.xCl.sub.y(OH).sub.(3x-y) or
M.sub.xCl.sub.y(OH).sub.(4x-y), where M is the metal ion. An
illustration of the reaction is as shown below (VII) taking copper
chloride as an example:
2CuCl+H.sub.2O+1/2O.sub.2.fwdarw.2CuClOH (VII)
[0123] Where the CuClOH species represents one of many possible
copper hydroxychloride species of stoichiometry
Cu.sub.xCl.sub.y(OH).sub.(2x-y). If in reaction with the propylene,
the CuCl.sub.2 is replaced (e.g. at least partially) by a
hydroxychloride, the following reaction (VIII) may take place:
C.sub.3H.sub.6(propylene)+CuClOH+CuCl.sub.2.fwdarw.ClCH.sub.2CH(OH)CH.su-
b.3(PCH)+2CuCl (VIII)
[0124] This reaction may allow for improved selectivity for the PCH
vs. the other products such as the DCP. The reaction with the
oxygen to form the metal hydroxychloride species of stoichiometries
as noted above, may occur in a reactor separate from the
chlorination reactor or may occur in the chlorination reactor
during the chlorination of the propylene. Other examples of the
metal hydroxychloride, without limitation include, MoCl(OH).sub.3,
MoCl.sub.2(OH).sub.2, and MoCl.sub.3(OH).
[0125] In some embodiments of the aforementioned aspect and
embodiments, the reaction conditions in the methods to form the PCH
comprise chlorinating in between about 1-30 wt % salt. The salt may
be between 1-30 wt %; or between 5-30 wt % salt; or between about
8-30 wt %; or between 10-30 wt %; or between 15-30 wt %; r between
20-30 wt %; or between 5-10 wt %. "Salt" as used herein includes
its conventional sense to refer to a number of different types of
salts including, but not limited to, alkali metal chlorides such
as, sodium chloride, potassium chloride, lithium chloride, cesium
chloride, etc.; alkaline earth metal chlorides such as, calcium
chloride, strontium chloride, magnesium chloride, barium chloride,
etc; or ammonium chloride. In some embodiments of the foregoing
aspects and embodiments, the salt comprises alkali metal chloride
or alkaline earth metal chloride. In some embodiments, the salt
(for example only, sodium chloride or calcium chloride) in the
chlorination includes between about 1-30 wt % salt; or between 1-25
wt % salt; or between 1-20 wt % salt; or between 1-10 wt % salt; or
between 5-30 wt % salt; or between 5-20 wt % salt; or between 5-10
wt % salt; or between about 8-30 wt % salt; or between about 8-25
wt % salt; or between about 8-20 wt % salt; or between about 8-15
wt % salt; or between about 10-30 wt % salt; or between about 10-25
wt % salt; or between about 10-20 wt % salt; or between about 10-15
wt % salt; or between about 15-30 wt % salt; or between about 15-25
wt % salt; or between about 15-20 wt % salt; or between about 20-30
wt % salt; or between about 20-25 wt % salt.
[0126] In some embodiments, the aqueous medium for the chlorination
reaction may contain between 5-50%; or 5-40%; or 5-30%; or 5-20%;
or 5-10%; or 50-75%; or 50-70%; or 50-65%; or 50-60% by weight of
water in the aqueous medium depending on the amount of salt and the
metal halide.
[0127] In some embodiments of the aforementioned aspect and
embodiments, the reaction conditions in the methods to form the PCH
comprise chlorinating in aqueous medium with total chloride content
of between about 10-30 wt %. The total chloride content is a
combination of chloride from the metal chloride as well as the
chloride from the salt. Applicants surprisingly observed that
chlorination in the aqueous medium with total chloride content
between about 10-30 wt % resulted in high yield and high
selectivity of the PCH over other side products.
[0128] In some embodiments, the reaction conditions in the methods
to form the PCH comprise varying the incubation time or residence
time or mean residence time of the chlorination mixture. The
"incubation time" or "residence time" or "mean residence time" as
used herein includes the time period for which the chlorination
mixture is left in the reactor at the above noted temperatures
before being taken out for the separation of the product. In some
embodiments, the residence time for the chlorination mixture is few
seconds or between about 1 sec-1 hour; or 1 sec-10 hours; or 10
min-10 hours or more depending on the temperature of the
chlorination mixture. This residence time may be in combination
with other reaction conditions such as, e.g. the temperature ranges
and/or total chloride concentrations provided herein. In some
embodiments, the residence time for the chlorination mixture is
between about 1 sec-3 hour; or between about 1 sec-2.5 hour; or
between about 1 sec-2 hour; or between about 1 sec-1.5 hour; or
between about 1 sec-1 hour; or 10 min-3 hour; or between about 10
min-2.5 hour; or between about 10 min-2 hour; or between about 10
min-1.5 hour; or between about 10 min-1 hour; or between about 10
min-30 min; or between about 20 min-3 hour; or between about 20
min-2 hour; or between about 20 min-1 hour; or between about 30
min-3 hour; or between about 30 min-2 hour; or between about 30
min-1 hour; or between about 1 hour-2 hour; or between about 1
hour-3 hour; or between about 2 hour-3 hour, to form the PCH as
noted herein.
[0129] In some embodiments, the reaction conditions in the methods
to form the PCH include carrying out the chlorination in the
presence of a noble metal. The "noble metal" as used herein
includes metals that are resistant to corrosion in moist
conditions. In some embodiments, the noble metals are selected from
ruthenium, rhodium, palladium, silver, osmium, iridium, platinum,
gold, mercury, rhenium, titanium, niobium, tantalum, and
combinations thereof. In some embodiments, the noble metal is
selected from rhodium, palladium, silver, platinum, gold, titanium,
niobium, tantalum, and combinations thereof. In some embodiments,
the noble metal is palladium, platinum, titanium, niobium,
tantalum, or combinations thereof. In some embodiments, the
foregoing noble metals may be present in 0, +2 or +4 oxidation
states as appropriate. For example only, platinum or palladium may
be present as metal or as a metal over carbon or may be present as
PtCl.sub.2 or PdCl.sub.2 etc. In some embodiments, the foregoing
noble metal is supported on a solid. Examples of solid support
include, without limitation, carbon, zeolite, titanium dioxide,
alumina, silica, and the like. In some embodiments, the foregoing
noble metal is supported on carbon. For example only, the catalyst
is palladium or palladium over carbon. The amount of nobel metal
used in the chlorination reaction is between 0.001M to 2M; or
between 0.001-1.5M; or between about 0.001-1M; or between about
0.001-0.5M; or between about 0.001-0.05M; or between 0.01-2M; or
between 0.01-1.5M; or between 0.01-1M; or between 0.01-0.5M; or
between 0.1-2M; or between 0.1-1.5M; or between 0.1-1M; or between
0.1-0.5M; or between 1-2M.
[0130] In some embodiments of the foregoing aspect and embodiments,
the method to form the PCH further comprises adding platinum or
palladium to the aqueous medium. In some embodiments of the
foregoing aspect and embodiments, the platinum or palladium is in
concentration of between about 0.001-0.1M.
[0131] In some embodiments of the foregoing aspects and
embodiments, total amount of chloride content in the aqueous medium
is between 4-15M or 4-10M. In some embodiments of the foregoing
aspects and embodiments, the aqueous medium in the chlorination
reaction comprises the metal chloride in the higher oxidation state
in range of 0.1-5M or 1-5M, or 1.5-5M, the metal chloride in the
lower oxidation state in range of 0.1-2M, and the sodium chloride
in range of 0.1-5M or 1-5M.
Forming the PCH from the DCP
[0132] As illustrated in FIG. 2, DCP may be another product formed
after the chlorination of propylene. The "1,2-dichloropropane" or
"dichloropropane" or "propylene dichloride" or "DCP" or "PDC" can
be used interchangeably. In some embodiments, the DCP may be formed
as a major product and in one aspect, there are provided methods
and systems to convert the DCP to the PCH in the same or a separate
reactor.
[0133] In one aspect, there are provided methods that include
chlorinating propylene in an aqueous medium comprising metal
chloride with metal ion in higher oxidation state and salt under
reaction conditions to result in one or more products comprising
DCP, and the metal chloride with the metal ion in lower oxidation
state; and hydrolyzing the DCP to PCH. In some embodiments of the
foregoing aspect, the one or more products further comprise PCH. In
some embodiments of the foregoing aspect and embodiments, the
method comprises one or more of (A) hydrolyzing the DCP to the PCH
in situ; (B) separating the DCP from the aqueous medium and/or from
the PCH (when both DCP and PCH are formed in the chlorination
reaction) and hydrolyzing the DCP to the PCH; and/or (C)
hydrolyzing the DCP to the PCH without the separation of the DCP
from the PCH and/or from the aqueous medium, to increase the yield
of the PCH. The electrochemical reaction/cell, the chlorination
reaction/reactor, the oxychlorination reaction/reactor, the
hydrolysis reaction/reactor, and the epoxidation reaction/reactor
are all illustrated in FIG. 3.
[0134] The chlorination reaction may take place after the
electrochemical reaction and/or the oxychlorination reaction.
Accordingly, in some embodiments there are provided methods that
include (i) contacting an anode with an anode electrolyte in an
electrochemical cell wherein the anode electrolyte comprises metal
chloride and saltwater; contacting a cathode with a cathode
electrolyte in the electrochemical cell; applying voltage to the
anode and the cathode and oxidizing the metal chloride with metal
ion in a lower oxidation state to a higher oxidation state at the
anode; (ii) withdrawing the anode electrolyte from the
electrochemical cell and chlorinating propylene with the anode
electrolyte comprising the metal chloride with the metal ion in the
higher oxidation state in the saltwater to result in one or more
products comprising DCP and the metal chloride with the metal ion
in the lower oxidation state; and (iii) hydrolyzing the DCP to the
PCH. In some embodiments, there are provided methods that include
(i) oxidizing metal chloride with metal ion in a lower oxidation
state to a higher oxidation state in presence of an oxidant in an
oxychlorination reaction; (ii) withdrawing the metal chloride with
metal ion in the higher oxidation state from the oxychlorination
reaction and chlorinating propylene with the metal chloride with
metal ion in the higher oxidation state in saltwater to result in
one or more products comprising DCP and the metal chloride with the
metal ion in the lower oxidation state; and (iii) hydrolyzing the
DCP to the PCH. In some embodiments of the foregoing aspect and
embodiments, the one or more products further comprise PCH. In some
embodiments of the foregoing aspect and embodiments, the method
further comprises one or more of (A) hydrolyzing the DCP to the PCH
in situ; (B) separating the DCP from the aqueous medium and/or from
the PCH and then hydrolyzing the DCP to the PCH; and/or (C)
hydrolyzing the DCP to the PCH without the separation of the DCP
from the PCH and/or the aqueous medium, to increase the yield of
the PCH. In some embodiments of the aforementioned embodiments, the
methods further include (iv) epoxidizing the PCH with a base to
form PO.
[0135] In one aspect, there is provided a system comprising (i) an
electrochemical cell comprising an anode chamber comprising an
anode and an anode electrolyte wherein the anode electrolyte
comprises metal chloride and saltwater and anode is configured to
oxidize metal chloride with metal ion in a lower oxidation state to
a higher oxidation state; a cathode chamber comprising a cathode
and a cathode electrolyte; and a voltage source configured to apply
voltage to the anode and the cathode; (ii) a chlorination reactor
operably connected to the anode chamber of the electrochemical cell
and configured to obtain the anode electrolyte and chlorinate
propylene with the anode electrolyte comprising the metal chloride
with the metal ion in the higher oxidation state in the saltwater
to result in one or more products comprising DCP and the metal
chloride with the metal ion in the lower oxidation state; (iii) a
hydrolysis reactor operably connected to the chlorination reactor
and configured to obtain the one or more products comprising DCP
from the chlorination reactor with or without the saltwater
comprising metal chloride and configured to hydrolyze the DCP to
the PCH; and (iv) an epoxidation reactor operably connected to the
hydrolysis reactor and configured to obtain the solution comprising
DCP and PCH and epoxidize the PCH to PO in presence of a base. In
some embodiments, the system further comprises an oxychlorination
reactor operably connected to the chlorination reactor and/or the
electrochemical cell, and the hydrolysis reactor and configured to
obtain aqueous medium from the chlorination reactor and/or the
electrochemical cell comprising the metal chloride with metal ion
in the lower oxidation state and the higher oxidation state and
obtain HCl produced in the hydrolysis reactor and configured to
oxidize the metal chloride with metal ion in the lower oxidation
state to the higher oxidation state using an oxidant comprising the
HCl and oxygen, or hydrogen peroxide (or any other oxidant as
described herein).
[0136] In one aspect, the oxychlorination reactor is used
independent of the electrochemical cell. In some embodiments, there
is provided a system comprising (i) oxychlorination reactor
configured to oxidize metal chloride with metal ion in lower
oxidation state to higher oxidation state using an oxidant
comprising HCl and oxygen, or hydrogen peroxide (or any other
oxidant as described herein); (ii) a chlorination reactor operably
connected to the oxychlorination reactor and configured to obtain
the metal chloride with the metal ion in the higher oxidation state
and chlorinate propylene with the metal chloride with the metal ion
in the higher oxidation state in saltwater to result in one or more
products comprising DCP and the metal chloride with the metal ion
in the lower oxidation state; (iii) a hydrolysis reactor operably
connected to the chlorination reactor and configured to obtain the
one or more products comprising DCP from the chlorination reactor
with or without the saltwater comprising metal chloride and
configured to hydrolyze the DCP to the PCH; and (iv) an epoxidation
reactor operably connected to the hydrolysis reactor and configured
to obtain the solution comprising DCP and PCH and epoxidize the PCH
to PO in presence of a base. In some embodiments, the
oxychlorination reactor is also operably connected to the
chlorination reactor and the hydrolysis reactor and is configured
to obtain the aqueous medium from the chlorination reactor
comprising the metal chloride with metal ion in the lower oxidation
state and the higher oxidation state and is configured to obtain
HCl produced in the hydrolysis reactor.
[0137] In some embodiments, the conversion of the DCP to the PCH is
a hydrolysis reaction:
ClCH.sub.2CH(Cl)CH.sub.3+H.sub.2O.fwdarw.ClCH.sub.2CH(OH)CH.sub.3+HCl
(IX)
ClCH.sub.2CH(Cl)CH.sub.3+H.sub.2O.fwdarw.HOCH.sub.2CH(Cl)CH.sub.3+HCl
(X)
[0138] In reactions (IX) and (X) above, the DCP is hydrolyzed by
water into two isomers of the PCH: 1-chloro-2-propanol and
2-chloro-1-propanol. The conversion of the DCP to the PCH is slow
at room temperature. In some embodiments, there are provided
efficient methods to convert the DCP to the PCH by hydrolysis.
[0139] In some embodiments, the reaction conditions listed in the
foregoing section also aid in (A) the hydrolysis of the DCP to the
PCH in situ (e.g. during chlorination reaction in the chlorination
reactor). The DCP may be hydrolyzed to the PCH in situ by
increasing the available free water during the reaction. Because
water is a reactant in the hydrolysis of the DCP to the PCH, the
presence of free water may lead to the conversion of the DCP to the
PCH.
[0140] In some embodiments, the DCP may be formed in high yield and
may then be hydrolyzed to the PCH (B and C above). In such
embodiments, some amount of PCH may be formed in the chlorination
reaction which may or may not be separated from the DCP. There may
be a number of options to increase the rate and/or selectivity of
the DCP formation. These options include highly concentrated salt
solutions which reduce the available free water. Because water is a
reactant in the hydrolysis of the DCP to the PCH, the presence of
free water may lead to the conversion of the DCP to the PCH. The
high concentrations of salt may be accomplished through the
addition of the copper chloride salts (such as CuCl.sub.2, CuCl or
in combination) or through other salts such as NaCl. There are also
a number of process conditions which can be optimized to provide
higher STY and better selectivity for the DCP production including
temperature, pressure (e.g. pressures under which the propylene may
form a liquid or supercritical phase), and residence time.
[0141] In one aspect, the conversion of the DCP to the PCH may be
executed in a second reaction step downstream (in a separate
reactor) of the propylene chlorination, illustrated as the
hydrolysis reactor in FIG. 3. The DCP may be hydrolyzed to the PCH
by (B) separating the DCP from the aqueous medium and/or from the
PCH (when both DCP and PCH are formed in the chlorination reaction)
and then hydrolyzing the DCP to the PCH; and/or (C) hydrolyzing the
DCP to the PCH without the separation of the DCP from the PCH
and/or the aqueous medium, to increase the yield of the PCH. When
the hydrolysis is done in a second step, the hydrolysis of the DCP
to the PCH may utilize the aqueous stream leaving the chlorination
reaction/reactor (containing the aqueous metal chloride, e.g.
aqueous copper chloride) as part of a circulating loop (embodiment
C above related to hydrolysis without the separation of the DCP
from the aqueous medium). Illustrated in FIG. 3 is the aspect where
the DCP is converted to the PCH in a hydrolysis reaction/reactor
after the chlorination reaction/reactor.
[0142] FIG. 3 illustrates that the chlorination is divided among
two reaction blocks. Block 1 effects propylene chlorination to one
or more products comprising the DCP (and optionally the PCH too).
Block 5 in FIG. 3 uses the aqueous copper chloride stream from
block 1 and hydrolyzes the DCP to the PCH. To leverage the process
economics of the conversion of the DCP to the PCH in an optimum
way, the process may recover at least some of the HCl by-product
from the hydrolysis of the DCP to the PCH (equations IX and X
above). This HCl can be reused in a traditional oxychlorination
reaction for the production of ethylene dichloride (EDC) or used in
the oxychlorination unit 2 within the process to generate
additional PO.
[0143] In some embodiments of the above noted aspect, the method
comprises (B) separating the DCP from the aqueous medium and/or
from the PCH and then hydrolyzing the DCP to the PCH. In such
embodiments, a separation step takes place between the chlorination
and the hydrolysis. In one aspect, there are provided methods to
form PCH, comprising: (i) contacting an anode with an anode
electrolyte in an electrochemical cell wherein the anode
electrolyte comprises metal chloride and saltwater; contacting a
cathode with a cathode electrolyte in the electrochemical cell;
applying voltage to the anode and the cathode and oxidizing the
metal chloride with metal ion in a lower oxidation state to a
higher oxidation state at the anode; (ii) withdrawing the anode
electrolyte from the electrochemical cell and chlorinating
propylene in the anode electrolyte comprising metal chloride with
metal ion in higher oxidation state and the saltwater to result in
one or more products comprising PCH and DCP, and the metal chloride
with the metal ion in lower oxidation state; (iii) separating the
PCH from the aqueous medium; and (iv) treating the aqueous medium
comprising the metal chloride with metal ions in the higher
oxidation state and the lower oxidation state and the DCP with
water to hydrolyze the DCP to the PCH. In one aspect, there are
provided methods to form PCH, comprising: (i) oxidizing metal
chloride with metal ion in a lower oxidation state to a higher
oxidation state in presence of an oxidant in an oxychlorination
reaction; (ii) withdrawing the metal chloride with metal ion in the
higher oxidation state from the oxychlorination reaction and
chlorinating propylene with the metal chloride with the metal ion
in the higher oxidation state in saltwater under reaction
conditions to result in one or more products comprising PCH and
DCP, and the metal chloride with the metal ion in lower oxidation
state; (iii) separating the PCH from the aqueous medium; and (iv)
treating the aqueous medium comprising the metal chloride with
metal ions in the higher oxidation state and the lower oxidation
state and the DCP with water to hydrolyze the DCP to the PCH. In
some embodiments of the foregoing aspects, the methods further
include (v) epoxidizing the PCH with a base to form propylene oxide
(PO). The PCH may be separated from the aqueous stream using
various separation techniques, including, but not limited to,
reactive separation, distillation, molecular sieve, membrane,
etc.
[0144] In another aspect, both the DCP and the PCH are separated
from the aqueous stream and the DCP is hydrolyzed to the PCH in the
absence of the metal salts used in the chlorination of the
propylene (e.g. metal chlorides used in the chlorination of
propylene). Accordingly, in one aspect, there are provided methods
to form PCH, comprising: (i) contacting an anode with an anode
electrolyte in an electrochemical cell wherein the anode
electrolyte comprises metal chloride and saltwater; contacting a
cathode with a cathode electrolyte in the electrochemical cell;
applying voltage to the anode and the cathode and oxidizing the
metal chloride with metal ion in a lower oxidation state to a
higher oxidation state at the anode; (ii) withdrawing the anode
electrolyte from the electrochemical cell and chlorinating
propylene in the anode electrolyte comprising metal chloride with
metal ion in higher oxidation state to result in one or more
products comprising PCH and DCP, and the metal chloride with the
metal ion in lower oxidation state; (iii) separating organics
comprising the PCH and the DCP from the aqueous medium comprising
the metal chloride with metal ions in the higher oxidation state
and the lower oxidation state; and (iv) hydrolyzing the DCP (also
containing PCH) with water to form the PCH. In one aspect, there
are provided methods to form PCH, comprising: (i) oxidizing metal
chloride with metal ion in a lower oxidation state to a higher
oxidation state in presence of an oxidant in an oxychlorination
reaction; (ii) withdrawing the metal chloride with metal ion in the
higher oxidation state from the oxychlorination reaction and
chlorinating propylene with the metal chloride with the metal ion
in the higher oxidation state in saltwater under reaction
conditions to result in one or more products comprising PCH and
DCP, and the metal chloride with the metal ion in lower oxidation
state; (iii) separating organics comprising the PCH and the DCP
from the aqueous medium comprising the metal chloride with metal
ions in the higher oxidation state and the lower oxidation state;
and (iv) hydrolyzing the DCP (also containing PCH) with water to
form the PCH.
[0145] In some embodiments of the foregoing aspects, the DCP is
separated from the PCH before the hydrolysis step. In some
embodiments of the foregoing aspects, the method further includes
(v) epoxidizing the PCH with a base to form propylene oxide
(PO).
[0146] In some embodiments, the hydrolysis step forms HCl and the
method further comprises recirculating the HCl to the
oxychlorination step (illustrated in FIG. 3) where the metal
chloride with the metal ion in the lower oxidation state is
converted to the metal chloride with the metal ion in the higher
oxidation state in presence of the HCl and oxygen, or hydrogen
peroxide, or any other oxidant described herein.
[0147] In some embodiments, the chlorination reaction may be run in
reaction conditions, such as, at elevated temperatures and at lower
metal chloride concentration. In such embodiments, both the PCH and
the DCP may be separated from the aqueous medium comprising metal
chloride as stated above.
[0148] In some embodiments, the step of separating the one or more
products comprising DCP from the chlorination reaction comprises
any separation method known in the art. In some embodiments, the
one or more products comprising DCP and optionally the PCH may be
separated from the chlorination reaction as a vapor stream. The
separated vapors may be cooled and/or compressed and subjected to
the hydrolysis reaction. Other separation methods include, without
limitation, distillation and/or flash distillation using the
distillation column or flash distillation column. The remaining one
or more products comprising DCP and optionally the PCH in the
aqueous medium may be further separated using methods such as,
decantation, extraction, or combination thereof. Various examples
of the separation methods are described in detail in U.S. patent
application Ser. No. 14/446,791, filed Jul. 30, 2014, which is
incorporated herein by reference in its entirety.
[0149] In one aspect, the DCP may be used as an extraction solvent
that extracts DCP and the PCH from the aqueous stream from the
chlorination reaction/reactor. The DCP used as the extraction
solvent can be DCP from the same process that has been separated
and recirculated and/or is the other DCP. The "other DCP" has been
described herein. The extraction solvent can be any organic solvent
that removes DCP and/or the PCH from the aqueous metal ion
solution. Applicants surprisingly found that in some embodiments,
the use of DCP as the extraction solvent may ensure that the
hydrolysis reaction, which occurs in an aqueous solution with metal
chlorides (aspect above) or without metal chlorides (another aspect
above), can have the maximum rate as the aqueous medium can be
saturated with the DCP. In some embodiments, the DCP may be present
in excess amount in order to facilitate efficient hydrolysis. In
some embodiments, the mol % of the DCP is equal to or greater than
the mol % of the PCH. In some embodiments, the DCP may be as high
as 10-95% by volume; or 10-90% by volume; or 10-80% by volume; or
10-70% by volume; or 10-60% by volume; or 10-50% by volume; or
10-40% by volume; or 10-30% by volume; or 10-20% by volume, of the
total solution volume. There may be several benefits to the use of
DCP as the extraction solvent. The DCP can form a second organic
phase which may help ensure that a soluble concentration of DCP
remains in the aqueous phase. In some embodiments, further
degradation of the PCH into other products (such as, but not
limited to, acetone and/or propylene glycol) may be minimized as
the PCH may preferentially partition into the DCP phase rather than
the aqueous phase. In a continuous operation, the PCH may be
removed from the reactor in the organic phase with the un-reacted
DCP. This last advantage may alleviate the need to separate the PCH
from the aqueous solution by other techniques such as distillation.
By extracting the PCH with the DCP, the PCH can be removed from the
chlorination reactor by removing the DCP layer that is
phase-separated from the aqueous layer.
[0150] FIG. 4 illustrates an example of the use of the DCP as an
extracting solvent. In FIG. 4, the recirculating DCP stream serves
to extract the PCH both from the propylene chlorination reactor
(block 1) and the hydrolysis reactor (block 5). The PCH recovered
from these reactors along with the DCP may be then sent to
epoxidation, where the PCH is converted to the PO and the DCP
stream is recirculated. In this configuration, any DCP made in the
propylene chlorination reactor may be balanced by conversion to the
PCH in the hydrolysis reactor. The extracting solvent as shown in
FIG. 4 can flow either clockwise or counterclockwise. The order of
operations may be determined by process economics. The epoxidation
of the PCH to the PO in the presence of the DCP has been described
below in detail.
[0151] In some embodiments, the DCP as the extraction solvent is
the DCP separated and recirculated from the same process (as
illustrated in FIG. 4) and/or is other DCP from other sources. The
process using the other DCP is as illustrated in FIG. 5. In this
embodiment, new or existing sources of chlorine to make the DCP via
direct chlorination of propylene, shown as block 7 in FIG. 5, is
connected to the chlorination reactor and/or the hydrolysis reactor
for the DCP to be converted to the PCH and ultimately to the PO.
The HCl formed as a by-product from the conversion to the PCH would
then be captured and reused. The direct chlorination reactor such
as traditional chlorohydrin process and/or direct chlorination of
propylene with chlorine may replace or supplement the
electrochemical and/or the oxychlorination processes provided
herein (oxychlorination shown as block 2 in FIG. 5).
[0152] Accordingly, in one aspect, there are provided methods to
form PCH, comprising: (i) contacting an anode with an anode
electrolyte in an electrochemical cell wherein the anode
electrolyte comprises metal chloride and saltwater; contacting a
cathode with a cathode electrolyte in the electrochemical cell;
applying voltage to the anode and the cathode and oxidizing the
metal chloride with metal ion in a lower oxidation state to a
higher oxidation state at the anode; (ii) withdrawing the anode
electrolyte from the electrochemical cell and chlorinating
propylene in the anode electrolyte comprising metal chloride with
metal ion in higher oxidation state to result in one or more
products comprising PCH and DCP, and the metal chloride with the
metal ion in lower oxidation state; (iii) extracting the one or
more products comprising PCH and DCP from the aqueous medium by
extracting with DCP as an extraction solvent; and (iv) hydrolyzing
the DCP with water to form the PCH. In one aspect, there are
provided methods to form PCH, comprising: (i) oxidizing metal
chloride with metal ion in a lower oxidation state to a higher
oxidation state in presence of an oxidant in an oxychlorination
reaction; (ii) withdrawing the metal chloride with metal ion in the
higher oxidation state from the oxychlorination reaction and
chlorinating propylene with the metal chloride with the metal ion
in the higher oxidation state in saltwater under reaction
conditions to result in one or more products comprising PCH and
DCP, and the metal chloride with the metal ion in lower oxidation
state; (iii) extracting the one or more products comprising PCH and
DCP from the aqueous medium by extracting with DCP as an extraction
solvent; and (iv) hydrolyzing the DCP with water to form the
PCH.
[0153] It is to be understood that in all the aspects and
embodiments provided herein, the anode electrolyte withdrawn from
the electrochemical cell and/or the metal chloride with metal ion
in the higher oxidation state withdrawn from the oxychlorination
reaction, comprise both the metal chloride with the metal ion in
the lower oxidation state as well as the metal chloride with the
metal ion in the higher oxidation state (e.g. CuCl.sub.x).
[0154] In some embodiments, the method further includes after
extraction, transferring aqueous medium comprising the metal
chloride with metal ions in the higher oxidation state and the
lower oxidation state to the oxychlorinating reaction/reactor; to
the hydrolysis reaction/reactor; to the chlorination
reaction/reactor; and/or to the electrochemical reaction/cell.
[0155] In some embodiments, the temperature and the residence time
in the hydrolysis reaction/reactor may be different from the one in
the chlorination reaction/reactor. For example, in some
embodiments, the hydrolysis reaction may be run at a lower
temperature than the chlorination reaction. Also, in some
embodiments, the residence time in the hydrolysis reaction may be
longer than that in the chlorination reaction. The extraction
method may be such that once the one or more products comprising
DCP and PCH are extracted from the aqueous medium using the DCP as
an extraction solvent, the organics are transferred to the
hydrolysis reaction; the aqueous stream comprising metal chloride
with metal ions in the higher oxidation state and the lower
oxidation state is added back to the hydrolysis reaction; and the
reaction is run at lower temperature and longer residence time so
that the DCP is hydrolyzed to the PCH. This may avoid more DCP
being formed and/or more PCH decomposing to form other side
products in the chlorination reaction.
[0156] In some embodiments of the above noted aspect, the method
further includes (v) transferring the organic medium comprising PCH
and DCP (remaining if any, after the hydrolyis) from the
hydrolyzing step to epoxidation; and (vi) epoxidizing the PCH with
a base to form PO in the presence of the DCP (described in detail
further herein below).
[0157] In some embodiments of the above noted aspects and
embodiments, the methods further comprise extracting the PCH formed
after the hydrolysis step from the aqueous medium using the DCP as
an extraction solvent. In some embodiments, where the DCP is used
as an extraction solvent for the PCH, the DCP may be separated from
the PCH and the separated DCP may be recirculated to the separation
reaction/reactor and/or to the hydrolysis reaction/reactor.
[0158] In some embodiments of the foregoing aspect and embodiments,
the one or more products further comprise isopropanol and/or
isopropyl chloride. In some embodiments of the foregoing aspect and
embodiments, the method further comprises converting the
isopropanol and/or the isopropyl chloride back to the propylene,
DCP, and/or PCH. In some embodiments, other isopropanol and/or
other isopropyl chloride (waste streams from other processes or
sources) may be used in this process and are converted to more
valuable propylene, DCP, and/or PCH.
[0159] The selectivity and the STY of the PCH formed by the methods
and systems provided herein, have been described earlier.
Reaction Conditions for the Hydrolysis of the DCP to the PCH
[0160] In the above noted aspects, a recirculating stream of the
DCP hydrolyzes to the PCH in the hydrolysis reactor by addition of
reactants and removal of products. Some reaction conditions such
as, but not limited to, low temperature and longer residence time
have been described above. In some embodiments, the hydrolysis
reactor runs at different pressure and temperature conditions than
the chlorination reactor and that drives the hydrolysis reaction.
For example, in some embodiments, since there is no propylene in
the hydrolysis reactor, it can be run at a lower pressure and/or
longer residence time than the chlorination reactor, thereby
expediting the hydrolysis reaction. In some embodiments, the
temperature of the hydrolysis reaction/reactor is between
20.degree. C.-200.degree. C. or between 90.degree. C.-160.degree.
C. In some embodiments, the residence time in the hydrolysis
reaction/reactor is less than two hrs; or less than one hr; or
between 1 sec-2 hrs; or between 1 min-1 hr. In some embodiments,
the hydrolysis of the DCP to the PCH in the hydrolysis reactor may
be catalyzed by the presence of a heterogenous catalyst, such as,
but not limited to, a noble metal. The noble metals have been
described herein for the formation of the PCH and can be used in
the hydrolysis of the DCP to the PCH as well.
[0161] In some embodiments of the aforementioned aspects, both the
DCP and the water may be minimally soluble in one another and as a
result the hydrolysis reactor may contain one or two liquid phases.
If the reactor contains both liquid phases, the reaction can
proceed in both phases, i.e. both the DCP which is soluble in the
water-rich phase and the water which is soluble in the DCP-rich
phase, may react. In the hydrolysis reactor, a single liquid phase
or both the DCP rich phase (with dissolved water) and the water
rich phase (with dissolved DCP) are contemplated.
[0162] In some embodiments, the hydrolysis of the DCP to the PCH
comprises concentration of the metal chloride with metal ion in the
higher oxidation state (for example only CuCl.sub.2) of between
about 1-3M.
[0163] In some embodiments of the above noted aspects, when the
metal chloride is copper chloride (CuCl as the metal chloride with
metal ions in the lower oxidation state and CuCl.sub.2 as the metal
chloride with metal ions in the higher oxidation state), the
hydrolysis of the DCP to the PCH may be carried out in presence of
copper hydroxychloride species of stoichiometry
Cu.sub.xCl.sub.y(OH).sub.(2x-y). The formation of the copper
hydroxychloride species of stoichiometry
Cu.sub.xCl.sub.y(OH).sub.(2x-y) via the oxychlorination reaction
has been described above. In some embodiments, the copper
hydroxychloride species of stoichiometry
Cu.sub.xCl.sub.y(OH).sub.(2x-y), such as, e.g. Cu(OH)Cl, can serve
as a base consuming HCl via:
Cu(OH)Cl+HCl.fwdarw.CuCl.sub.2+H.sub.2O (XI)
[0164] In some embodiments, the Cu(OH)Cl may serve as an active
site to form the PCH directly from the DCP as shown in reaction
(XII) below:
Cu(OH)Cl+ClCH.sub.2CH(Cl)CH.sub.3.fwdarw.ClCH.sub.2CH(OH)CH.sub.3+CuCl.s-
ub.2 (XII)
[0165] Without being limited by any theory, it is contemplated that
either or both of the reactions may occur in the presence of copper
hydroxychloride species of stoichiometry
Cu.sub.xCl.sub.y(OH).sub.(2x-y), such as, e.g. Cu(OH)Cl.
Forming the PO from the PCH
[0166] In some embodiments of the foregoing aspect and embodiments,
the methods further comprise reacting the PCH with a base to form
the PO. Various process configurations that lead to the epoxidation
step have been described above and are illustrated in the figures
herein.
[0167] Typically, the conversion of the PCH to the PO is a
ring-closing reaction whereby the chlorohydrin molecule may be
combined in a near stoichiometric ratio with a base such as e.g.
sodium hydroxide (NaOH) or lime (CaO). The products are PO, the
chloride salt of the base (e.g. NaCl or CaCl.sub.2 respectively)
and water. Because the PO may be a reactive molecule, it may need
to be removed from the reaction media quickly. Typically, the short
residence time requirement may be achieved by steam stripping the
PO as it is formed in the reactor. However, because the PCH feeding
the reactor may be diluted with a large excess of water due to
upstream reaction selectivity considerations (described further
herein below), the steam demand for PO stripping may be very
high.
[0168] In some aspects noted above, there are provided methods and
systems comprising reacting the PCH with a base to form PO in
presence of DCP or the methods and systems comprise reacting the
solution of the PCH and the DCP with a base to form PO. In these
aspects, the DCP is not separated from the PCH after hydrolysis and
the solution is directly subjected to epoxidation. In such
embodiments, the separation of the DCP and the PCH step (before
and/or after hydrolysis step) may be combined with the epoxidation
step such that when the base is added into the epoxidation reactor,
the base reacts with the PCH to form the PO, which may leave the
reactor as a vapor. In this process, some DCP may be converted to
the PCH which would also form the PO. In some embodiments, the
residual levels of un-reacted PCH may leave the reactor in the DCP
extraction solvent (DCP as an extraction solvent has been described
before) and return to the process where appropriate.
[0169] The methods and systems provided herein for converting the
PCH to the PO in the presence of the DCP (where the mol % of the
DCP may be equal to or greater than the mol % of the PCH) has a
number of advantages. First, it may obviate the need for separation
of the PCH from the DCP prior to the epoxidation. To maintain high
selectivity of the PCH during the hydrolysis reaction, the DCP
level may be in excess relative to the converted amount of the DCP
as described above. The PCH may be separated from the DCP via a
typical separation operation. If PCH were the lighter (lower
boiling) component, distillation would be an option. However,
because PCH is the heavier component, separation by distillation
may require the excess DCP be removed in the overhead of the column
which in turn may lead to prohibitive steam demand. Alternative
separation technologies, such as absorption or selective
permeation, may be equally prohibitive due to either capital
equipment costs or operating costs. Second, because the PO may also
be soluble in the DCP, the reactor may not require steam stripping
inside the reactor. The PO can be removed from the reactor in the
DCP phase if desired and separated downstream. Third, additional
side reactions may be minimized because PO may react much more
slowly in the organic (DCP) phase. Finally, the total waste water
demand may be significantly reduced because the water leaving the
reactor would primarily be that which came in with the caustic (and
low levels of soluble water with the organic phase). In some
embodiments, when using NaOH as the base for the PO formation, the
resulting aqueous solution may be concentrated enough in NaCl to
merit removing the waste organics and using the brine back in the
electrochemical cell.
[0170] In addition to the advantages described above, the
conversion of the PCH to the PO in the presence of DCP may also
allow for process options that minimize by-product losses, such as,
a single aqueous phase reactor that contains both reactants and
products; minimizing by-product formation by running the reactor
with a short residence time; step-wise addition of the NaOH; and
recycling of the product stream back to the reactor. The step-wise
addition of NaOH (e.g. along a length of pipe if the reaction is
done in a continuous system) may reduce the by-product formation
because the aqueous salt solutions resulting from the early
additions may dilute the later additions. In this way, the caustic
concentrations within the aqueous phase can be more easily managed
along the reactor length. The recycling of the aqueous product
stream back to the reactor inlet may also minimize the NaOH
concentration in the aqueous phase. The recycling option has other
advantages too. For example, the recycle stream may return
salt-rich brine to the reactor. The presence of the salt may
minimize the solubility of the PO in the aqueous phase which may
improve reactor selectivity. Further, the highly concentrated salt
may be advantageous because the resulting brine stream exiting the
epoxidation unit may serve as a feedstock for electrolysis cells
after removal of the residual, soluble organics. Furthermore, the
recycle of reactor outlet may allow the reactor to run in such a
way as to produce a high salt concentration outlet stream without
having to feed a high concentration NaOH stream directly to the
reactor. The other advantages of the high salt concentration outlet
stream have also been described further herein.
[0171] In some embodiments of the foregoing aspect and embodiments,
the base is an alkali metal hydroxide, such as e.g. NaOH or alkali
metal oxide; alkaline earth metal hydroxide or oxide, such as e.g.
Ca(OH).sub.2 or CaO; or metal hydroxide chloride (for example only,
M.sub.x.sup.n+Cl.sub.y(OH).sub.(nx-y)). In some embodiments of the
foregoing aspect and embodiments, metal in the metal
hydroxychloride is same as metal in the metal chloride. In some
embodiments of the foregoing aspect and embodiments, the method
further comprises forming the metal hydroxychloride by
oxychlorinating the metal chloride with the metal ion in the lower
oxidation state to the higher oxidation state in presence of water
and oxygen (as explained above).
[0172] Typically, in chlorohydrin processes for the production of
propylene oxide, the NaOH may be combined and reacted with an
approximately 4-5 wt % solution of propylene chlorohydrins. The
propylene chlorohydrins are a mix of 1-chloro-2-propanol
(approximately 85-90%) and 2-chloro-1-propanol (approximately
10-15%). The propylene oxide formation reaction is shown as
below:
C.sub.3H.sub.6(OH)Cl+NaOH.fwdarw.C.sub.3H.sub.6O(PO)+NaCl+H.sub.2O
(XIII)
[0173] Propylene oxide may be rapidly stripped from the solution in
either a vacuum stripper or steam stripper. A primary disadvantage
of the process may be the generation of a dilute NaCl brine stream
with about 3-6 wt % NaCl with flow rate exceeding 40-45 tonnes of
brine per tonne of propylene oxide. The large amount of dilute
brine may result in large amount of waste water. The reason for the
large volume of water may be that the reactor producing the
propylene chlorohydrins must operate at dilute concentrations of
about 4-5 wt % propylene chlorohydrin in order to achieve high
selectivity.
[0174] Applicants have discovered that using the methods of the
invention that produce PCH in high selectivity and high STY, the
amount of dilute brine generated after the PO formation can be
substantially reduced. In some embodiments of the foregoing aspect
and embodiments, the reaction forms between about 5-40 tonnes of
brine per tonne of PO which is substantially less brine compared to
the brine generated in a typical PO reaction.
[0175] In one aspect, there is provided a method to form propylene
oxide (PO), comprising chlorinating propylene in an aqueous medium
comprising metal chloride with metal ion in higher oxidation state
and salt to result in one or more products comprising between about
5-99.9 wt % PCH, and the metal chloride with the metal ion in lower
oxidation state; and reacting the PCH with a base to form PO and
brine in water, wherein the reaction forms between about 5-42
tonnes of brine per tonne of PO.
[0176] In one aspect, there is provided a method to form propylene
oxide (PO), comprising chlorinating propylene in an aqueous medium
comprising metal chloride with metal ion in higher oxidation state
and salt to result in one or more products comprising DCP and PCH,
and the metal chloride with the metal ion in lower oxidation state;
extracting the DCP and the PCH with re-circulating DCP from the
same process and/or the other DCP; hydrolyzing the DCP in the
mixture of the DCP and the PCH to the PCH; and reacting the PCH in
presence of remaining DCP with a base to form PO and brine in
water. In some embodiments of the foregoing aspect, the reaction
forms between about 5-42 or about 5-40 tonnes of brine per tonne of
PO. In some embodiments of the foregoing aspect, the selectivity of
the PCH formed (after chlorination and hydrolysis) is between about
10-99.9 wt %. In some embodiments of the foregoing aspect and
embodiments, the base is between about 5-35 wt % or between about
8-15 wt %. The bases have been described herein and include without
limitation, the alkali metal hydroxide e.g. sodium hydroxide or
potassium hydroxide; alkaline earth metal hydroxide e.g. calcium
hydroxide or oxide e.g. CaO or MgO; or metal hydroxide chloride.
The PO formation has been illustrated in FIGS. 1-5.
[0177] In some embodiments of the aforementioned aspects, the PO
formed is between about 5-50 wt %; or between about 5-40 wt %; or
between about 5-30 wt %; or between about 5-20 wt %; or between
about 5-10 wt %; or between about 10-50 wt %; or between about
10-40 wt %; or between about 10-30 wt %; or between about 10-20 wt
%; or between about 20-50 wt %; or between about 20-40 wt %; or
between about 20-30 wt %; or between about 30-50 wt %; or between
about 30-40 wt %; or between about 40-50 wt %. In some embodiments
of the aspects and embodiments provided herein, the PO formed is
between about 1-25 wt %; or between about 2-20 wt %; or between
about 3-15 wt %.
[0178] In some embodiments of the aspect and embodiments provided
herein, the reaction forms between about 5-42 tonnes of brine per
tonne of PO; or between about 5-40 tonnes of brine per tonne of PO;
or between about 5-35 tonnes of brine per tonne of PO; or between
about 5-30 tonnes of brine per tonne of PO; or between about 5-25
tonnes of brine per tonne of PO; or between about 5-20 tonnes of
brine per tonne of PO; or between about 5-10 tonnes of brine per
tonne of PO. In some embodiments of the aspect and embodiments
provided herein, the reaction forms between about 3-40 tonnes of
brine per tonne of PO; or between about 4-20 tonnes of brine per
tonne of PO; or between about 4-12 tonnes of brine per tonne of
PO.
[0179] In some embodiments of the aspect and embodiments provided
herein, the base is between about 5-50 wt %; or between about 5-40
wt %; or between about 5-30 wt %; or between about 5-20 wt %; or
between about 5-10 wt %; or between about 10-50 wt %; or between
about 10-40 wt %; or between about 10-30 wt %; or between about
10-20 wt %; or between about 20-50 wt %; or between about 20-40 wt
%; or between about 20-30 wt %; or between about 30-50 wt %; or
between about 30-40 wt %; or between about 40-50 wt %; or between
about 8-15 wt %; or between about 10-15 wt %; or between about
12-15 wt %; or between about 14-15 wt %; or between about 8-10 wt
%; or between about 8-12 wt %. In some embodiments of the aspect
and embodiments provided herein, the base is between about 5-38 wt
%; or between about 7-33 wt %; or between about 8-20 wt %.
[0180] In some embodiments of the foregoing aspects and embodiment,
the method further comprises transferring aqueous medium comprising
the metal chloride with the metal ion in the lower oxidation state
and the salt to an anode electrolyte in contact with an anode in an
electrochemical cell and oxidizing the metal ion from the lower
oxidation state to the higher oxidation state at the anode.
[0181] In some embodiments of the foregoing aspects and embodiment,
the method further comprises transferring the aqueous medium
comprising the metal chloride with the metal ion in the lower
oxidation state and the salt to an oxychlorination reaction and
oxidizing the metal ion from the lower oxidation state to the
higher oxidation state in the presence of the oxidant.
[0182] In some embodiments of the foregoing aspect and embodiments,
the one or more products further comprise hydrochloric acid (HCl).
In some embodiments of the foregoing aspect and embodiments, the
method further comprises after the chlorinating step,
oxychlorinating the metal chloride with the metal ion in the lower
oxidation state to the metal ion in the higher oxidation state in
presence of the HCl and oxygen, or hydrogen peroxide.
[0183] In some embodiments of the foregoing aspect and embodiments,
the method further comprises recirculating the metal chloride in
the higher oxidation state back to the chlorinating step.
[0184] In the methods and systems provided herein, the separation
and/or purification may include one or more of the separation and
purification of the organic products from the metal ion solution
and/or the separation and purification of the organic products from
each other, to improve the overall yield of the PCH, improve
selectivity of the PCH, improve purity of the PCH, improve
efficiency of the systems, improve ease of use of the solutions in
the overall process, improve reuse of the metal solution, and/or to
improve the overall economics of the process.
[0185] In some embodiments, the solution containing the one or more
products and the metal chloride may be subjected to a washing step
which may include rinsing with an organic solvent or passing the
organic product through a column to remove the metal ions. In some
embodiments, the organic products may be purified by
distillation.
[0186] In one aspect, there are provided systems, comprising
reactors configured to carry out the reactions of the preceding
aspects and embodiments.
[0187] The systems provided herein include one or more reactors
that carry out the chlorination reaction; the hydrolysis reaction;
the oxychlorination reaction; and the epoxidation reaction. The
"reactor" as used herein is any vessel or unit in which the
reaction provided herein is carried out. For example, the
chlorination reactor is configured to contact the metal chloride
solution with the propylene to form the one or more products
comprising DCP and/or PCH. The reactor may be any means for
contacting the metal chloride with the propylene. Such means or
such reactor are well known in the art and include, but not limited
to, pipe, column, duct, tank, series of tanks, container, tower,
conduit, and the like. The reactor may be equipped with one or more
of controllers to control temperature sensor, pressure sensor,
control mechanisms, inert gas injector, etc. to monitor, control,
and/or facilitate the reaction.
[0188] In some embodiments, the reactor system may be a series of
reactors connected to each other. For example, to increase the
yield of the PCH, the chlorination mixture may be kept either in
the same reaction vessel (or reactor), or in a second reaction
vessel (hydrolysis reactor) that does not contain additional
propylene. Since the PCH and/or the DCP solubility may be limited
in the aqueous medium, a second reaction vessel may be a stirred
tank. The stirring may increase the mass transfer rate of the PCH
and/or the DCP into the aqueous medium accelerating the reaction to
the PCH.
[0189] The reactor configuration includes, but is not limited to,
design parameters of the reactor such as, e.g. length/diameter
ratio, flow rates of the liquid(s) and gas(es), material of
construction, packing material and type of reactor such as, packed
column, bubble column, or trickle-bed reactor, or combinations
thereof. In some embodiments, the systems may include one reactor
or a series of multiple reactors connected to each other or
operating separately. The reactor may be a packed bed such as, but
not limited to, a hollow tube, pipe, column or other vessel filled
with packing material. The reactor may be a spray reactor. The
reactor may be a trickle-bed reactor. The reactor may be a bubble
column. In some embodiments, the packed bed reactor includes a
reactor configured such that the aqueous medium containing the
metal ions and the propylene flow counter-currently in the reactor
or includes the reactor where the aqueous medium containing the
metal ions flows in from the top of the reactor and the propylene
gas is pressured in from the bottom. In some embodiments, in the
latter case, the propylene may be fed in such a way that only when
the propylene gets consumed, that more propylene flows into the
reactor. The trickle-bed reactor includes a reactor where the
aqueous medium containing the metal ions and the propylene flow
co-currently in the reactor.
[0190] In some embodiments, the reactor may be configured for both
the reaction and separation of the products. The processes and
systems described herein may be batch processes or systems or
continuous flow processes or systems.
[0191] The following examples are put forth so as to provide those
of ordinary skill in the art with a complete disclosure and
description of how to make and use the present invention, and are
not intended to limit the scope of what the inventors regard as
their invention nor are they intended to represent that the
experiments below are all or the only experiments performed.
Various modifications of the invention in addition to those
described herein will become apparent to those skilled in the art
from the foregoing description and accompanying figures. Such
modifications fall within the scope of the appended claims. Efforts
have been made to ensure accuracy with respect to numbers used
(e.g. amounts, temperature, etc.) but some experimental errors and
deviations should be accounted for. Unless indicated otherwise,
parts are parts by weight, molecular weight is weight average
molecular weight, temperature is in degrees Centigrade, and
pressure is at or near atmospheric.
[0192] In the examples and elsewhere, abbreviations have the
following meanings:
TABLE-US-00001 g = gram M = molar mmol = millimole mol = mole
mol/kg = mole/kilogram .mu.l = microliter ml = milliliter N =
normal psi = pounds per square inch psig = pounds per square inch
guage Pt = platinum rpm = revolutions per minute STY = space time
yield umol = micromole
EXAMPLES
Example 1
Formation of PCH, DCP, Isopropanol and Isopropyl Chloride from
Propylene Using Copper Chloride
Experiment 1
[0193] A solution of CuCl.sub.2 (1.0 mol/kg), CuCl (0.19 mol/kg),
NaCl (0.66 mol/kg), and HCl (0.0091 mol/kg) was heated in a Parr
reactor under propylene pressure to 130.degree. C. for 15 minutes.
The reactor was depressurized into a bubbler trap at 0.degree. C.
to capture volatile compounds. When the reactor was opened, the
solution was extracted three times with an organic solvent, e.g.
ethyl acetate or dichloromethane, which was analyzed with a gas
chromatograph equipped with a mass spectrometer. A total of 11.4
umol DCP and 12.0 umol PCH were measured. The amounts of recyclable
products measured were 622 umol isopropanol, 47.9 umol acetone, and
73.0 umol isopropyl chloride.
Experiment 2
[0194] A solution of CuCl.sub.2 (0.71 mol/kg), CuCl (0.71 mol/kg),
and NaCl (2.76 mol/kg) was heated in a Parr reactor under propylene
pressure to 150.degree. C. for 15 minutes. The reactor was
depressurized into a bubbler trap at 0.degree. C. to capture
volatile compounds. When the reactor was opened, the solution was
extracted three times with an organic solvent, e.g. ethyl acetate
or dichloromethane, which was analyzed with a gas chromatograph
equipped with a mass spectrometer. A total of 15.6 umol DCP and
62.4 umol PCH were measured. The amounts of recyclable products
measured were 1087 umol isopropanol, 18.8 umol acetone, and 80.1
umol isopropyl chloride.
Example 2
Formation of PCH from Propylene Using Palladium Chloride and Copper
Chloride
[0195] A solution of CuCl.sub.2 (2.80 mol/kg), CuCl (0.54 mol/kg),
NaCl (1.84 mol/kg), and PdCl.sub.2 (0.012 mol/kg) are heated in a
Parr reactor under propylene pressure to 130.degree. C. for 15
minutes. The reactor was depressurized into a bubbler trap at
0.degree. C. to capture volatile compounds. When the reactor was
opened, the solution was extracted three times with an organic
solvent, e.g. ethyl acetate or dichloromethane, which was analyzed
with a gas chromatograph equipped with a mass spectrometer. A total
of 0.29 mmol DCP and 1.24 mmol PCH were measured. The amounts of
recyclable products measured were 9.23 mmol isopropanol, 3.17 mmol
acetone, and 10.9 mmol isopropyl chloride.
Example 3
Recycling of Isopropanol
[0196] A solution of CuCl.sub.2 (3.0 mol/kg), CuCl (0.50 mol/kg),
and NaCl (2.0 mol/kg) were heated with added isopropanol in a Parr
reactor at 140.degree. C. for 15 minutes. The reactor was
constantly purged with a flow of N.sub.2 into a bubbler trap at
0.degree. C. to capture volatile compounds. When the reactor was
opened, the solution was extracted three times with an organic
solvent, e.g. ethyl acetate or dichloromethane, which was analyzed
with a gas chromatograph equipped with a mass spectrometer.
Propylene, isopropanol, isopropyl chloride, PCH, and DCP were all
detected, indicating that isopropanol can be recycled and converted
into desired products.
Example 4
Recycling of Isopropyl Chloride
[0197] Similar to Example 3, reaction was conducted with isopropyl
chloride instead of isopropanol. The same products were
observed.
Example 5
Conversion of DCP to PCH
[0198] In order to measure conversion of DCP to PCH, seven aqueous
salt solutions were tested. The salt solutions comprised
CuCl.sub.2, CuCl, and NaCl. The salts were weighed into 10 ml vials
with water added to bring the solution volume to approximately 4
ml. 50 .mu.L of DCP was added to each vial and then a stir bar was
also added. The vials were closed with a split-septa cap and placed
inside an 8 well high throughput reactor. The entire system was
heated to 150.degree. C. for 30 minutes, during which time the
vials were all stirred at 600 rpm. The organics were extracted
using 4 ml of ethyl acetate and the resulting solutions were
measured by GC-MS. Using the peak areas from the GC-MS, the
following conversions were obtained shown in Table
TABLE-US-00002 TABLE I Experiment 1 2 3 4 5 6 7 CuCl.sub.2 3.0 3.0
1.5 3.0 3.0 0.0 0.0 (mol/kg) CuCl 1.0 1.0 0.5 0.0 0.0 1.0 1.0
(mol/kg) NaCl 2.0 0.0 1.0 2.0 0.0 2.0 0.0 (mol/kg) Estimated 7.0%
12.7% 10.1% 7.2% 10.7% 14.7% 13.6% Conver- sion To PCH
[0199] It may be noted that some DCP partitions into the vapor
space in the vials, therefore, these numbers represent a lower
bound on the conversion to PCH. It was observed that lower
CuCl.sub.2 concentrations lead to higher conversion to PCH.
Example 6
Improved Selectivity for PCH Over DCP
Experiment 1
[0200] An aqueous solution of CuCl.sub.2 (2.0 mol/kg) and CuCl (1.0
mol/kg) was heated in a Parr reactor under propylene pressure to
140.degree. C. for 30 minutes. The reactor was depressurized into a
bubbler trap at 0.degree. C. to capture volatile compounds. When
the reactor was opened, the solution was extracted three times with
an organic solvent, e.g. ethyl acetate or dichloromethane, which
was analyzed with a gas chromatograph equipped with a mass
spectrometer. A total of 47 umol DCP and 229 umol PCH were
measured. The amounts of recyclable products measured were 5834
umol isopropanol, 23 umol acetone, and 189 umol isopropyl
chloride.
Experiment 2
[0201] An aqueous solution of CuCl.sub.2 (1.0 mol/kg), CuCl (1.0
mol/kg), and NaCl (1.0 mol/kg) was heated in a Parr reactor under
propylene pressure to 140.degree. C. for 30 minutes. The reactor
was depressurized into a bubbler trap at 0.degree. C. to capture
volatile compounds. When the reactor was opened, the solution was
extracted three times with an organic solvent, e.g. ethyl acetate
or dichloromethane, which was analyzed with a gas chromatograph
equipped with a mass spectrometer. A total of 15 umol DCP and 88
umol PCH were measured. The amounts of recyclable products measured
were 917 umol isopropanol, 4 umol acetone, and 35 umol isopropyl
chloride.
Example 7
Lowering of Water in PO Process
[0202] A 40 wt % solution of propylene chlorohydrin is combined
with a 10 wt % solution of sodium hydroxide and brine. The use of
the more concentrated PCH reduces the brine effluent from 46.2 to
10.1 tonnes per tonne of propylene oxide resulting in significant
cost savings for the handling of this stream. In another example,
feeding a solution of PCH in DCP may lower the total water
discharged to around 7 tonnes per tonne PO, which is due to the
amount of water contained in the added NaOH solution.
Example 8
Formation of PO from PCH
[0203] A glass vial was loaded with 5 mL of 0.1 N NaOH and 100 ul
of PCH (70% 1-chloro-2-propanol and 30% 2-chloro-1-propanol). The
vial was stirred with a magnetic stir bar for 20 hours. Afterward,
a 1 ml aliquot was extracted with 2 ml of ethyl acetate that was
subsequently analyzed by gas chromatography with a mass
spectrometer detector. Propylene oxide as well as both isomers of
PCH was observed, as determined by their fragmentation
patterns.
Example 9
Formation of PO from PCH in Presence of DCP
[0204] A 500 ml round bottom flask was charged with 99.90 g DCP,
0.933 g octane as an internal standard, and 4.764 g (50.4 mmol)
PCH. The flask was equipped with a condenser on top of which was a
barbed fitting with a tube that ran into a vial of ethyl acetate in
ice water bath. Any gas generated and distilled through the
condenser was collected in the ethyl acetate trap. The solution was
brought to a boil at roughly 90.degree. C. At specific time
intervals, 4 charges each of 10 ml of 1 N NaOH (10 mmol) was added
through the top of the condenser and allowed to trickle down into
the hot solution. At the end of the reaction, 34.5 mmol propylene
oxide and 3.0 mmol propylene glycol were measured as products, and
7.9 mmol PCH was measured as un-reacted. This correlates to 92%
propylene oxide with 90% mass balance closure.
Example 10
Formation of PO from PCH in Presence of DCP
[0205] A glass vial was charged with 1900 ul DCP and 100 ul (1.2
mmol) PCH and held at room temperature. To this, 300 ul 1 N NaOH
(0.3 mmol) was added and the vial was mixed vigorously. Samples
from before and after the reaction showed a reduction of the PCH
amount by 31% with a concomitant increase in propylene oxide.
* * * * *