U.S. patent application number 14/385917 was filed with the patent office on 2015-10-22 for catalysts and methods for alcohol dehydration.
This patent application is currently assigned to The Dow Chemical Company. The applicant listed for this patent is Dow Global Technologies LLC. Invention is credited to David G. Barton, Adam Chojecki, Paul R. Elowe, Beata A. Kilos.
Application Number | 20150299077 14/385917 |
Document ID | / |
Family ID | 48626632 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150299077 |
Kind Code |
A1 |
Barton; David G. ; et
al. |
October 22, 2015 |
CATALYSTS AND METHODS FOR ALCOHOL DEHYDRATION
Abstract
Provided is a process for preparing a diaryl ether compound
through the dehydration of an aromatic alcohol compound in the
presence of a dehydration catalyst. The dehydration catalyst is an
oxide of a heavy rare earth element, wherein the heavy rare earth
element is terbium, dysprosium, holmium, erbium, thulium,
ytterbium, lutetium, or mixtures thereof.
Inventors: |
Barton; David G.; (Midland,
MI) ; Chojecki; Adam; (Gent, BE) ; Elowe; Paul
R.; (Midland, MI) ; Kilos; Beata A.; (Midland,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dow Global Technologies LLC |
Midland |
MI |
US |
|
|
Assignee: |
The Dow Chemical Company
Midland
MI
|
Family ID: |
48626632 |
Appl. No.: |
14/385917 |
Filed: |
May 29, 2013 |
PCT Filed: |
May 29, 2013 |
PCT NO: |
PCT/US2013/043092 |
371 Date: |
September 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61653494 |
May 31, 2012 |
|
|
|
Current U.S.
Class: |
252/79 ;
568/635 |
Current CPC
Class: |
B01J 37/031 20130101;
C07C 41/09 20130101; B01J 21/066 20130101; C07C 41/09 20130101;
C07C 43/275 20130101; B01J 27/10 20130101; B01J 37/0201 20130101;
C09K 5/00 20130101 |
International
Class: |
C07C 41/09 20060101
C07C041/09; C09K 5/00 20060101 C09K005/00 |
Claims
1. A method for preparing a diaryl ether, the method comprising
dehydrating an aromatic alcohol compound over a dehydration
catalyst, wherein the dehydration catalyst is an oxide of a heavy
rare earth element.
2. The method of claim 1 wherein the dehydration catalyst further
comprises a halogen.
3. The method of claim 2 wherein the halogen is chloride or
fluoride ion.
4. The method of claim 1 wherein the dehydration catalyst further
comprises a binder.
5. The method of claim 1 wherein the dehydration catalyst is
supported.
6. The method of claim 1 wherein the dehydration catalyst is
unsupported.
7. The method of claim 1 wherein the dehydration of the alcohol is
conducted at a temperature from 250 to 600.degree. C.
8. The method of claim 1 wherein the alcohol feed is diluted with a
diluent.
9. The method of claim 1 wherein the aromatic alcohol compound is
phenol and the diaryl ether produced is diphenyl oxide.
10. A method for producing a heat transfer fluid, the method
comprising: preparing a diaryl ether by contacting an aromatic
alcohol compound with a dehydration catalyst, wherein the
dehydration catalyst is an oxide of a heavy rare earth element;
isolating the diaryl ether from the dehydration catalyst; and
mixing the isolated diaryl ether with biphenyl, wherein the mixture
forms a eutectic mixture.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from provisional
application Ser. No. 61/653,494, filed May 31, 2012, which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] This invention relates generally to catalysts and methods
for the dehydration of aromatic alcohol compounds to ethers. More
particularly, the invention uses a dehydration catalyst comprising
an oxide of a heavy rare earth element for the dehydration of
aromatic alcohol compounds to diaryl ethers.
[0003] Diaryl ethers are an important class of industrial
materials. Diphenyl oxide (DPO), for instance, has many uses, most
notably as the major component of the eutectic mixture of DPO and
biphenyl, which is the standard heat transfer fluid for the
concentrating solar power (CSP) industry. With the current boom in
CSP has come a tightening of the supply of DPO globally and
questions surrounding the sustainability of the technology have
arisen.
[0004] Diaryl ethers are currently manufactured commercially via
two major routes: reaction of a haloaryl compound with an aryl
alcohol; or gas-phase dehydration of an aryl alcohol. The first
route, for example where chlorobenzene reacts with phenol in the
presence of caustic and a copper catalyst, typically leads to less
pure product and requires high pressure (5000 psig), uses an
expensive alloy reactor and produces stoichiometric quantities of
sodium chloride.
[0005] The second route, which is a more desirable approach,
accounts for the largest volume of diaryl ethers produced but
requires a very active and selective catalytic material. For
instance, DPO can be manufactured by the gas-phase dehydration of
phenol over a thorium oxide (thoria) catalyst (e.g., U.S. Pat. No.
5,925,798). A major drawback of thoria however is its radioactive
nature, which makes its handling difficult and potentially costly.
Furthermore, the supply of thoria globally has been largely
unavailable in recent years putting at risk existing DPO
manufacturers utilizing this technology. Additionally, other
catalysts for the gas-phase dehydration of phenol, such as zeolite
catalysts, titanium oxide, zirconium oxide and tungsten oxide,
generally suffer from lower activity, significantly higher impurity
content and fast catalyst deactivation.
[0006] With a chronic shortage of diaryl ethers such as DPO in
sight and a pressing need to increase capacity, it has become
crucial to develop alternate methods to produce such materials in a
cost-effective and sustainable manner.
[0007] The problem addressed by this invention, therefore, is the
provision of new catalysts and methods for manufacture of diaryl
ethers from aryl alcohol compounds.
STATEMENT OF INVENTION
[0008] We have now found that a catalyst comprising an oxide of a
heavy rare earth element is effective for the preparation of diaryl
ethers from aromatic alcohol compounds. Advantageously, the
catalyst exhibits remarkable selectivity for the desired product.
Moreover, the catalyst is non-radioactive. This invention,
therefore, represents a unique solution for diaryl ether supply
issues globally.
[0009] In one aspect, there is provided a method for preparing a
diaryl ether, the method comprising dehydrating an aromatic alcohol
compound over a dehydration catalyst, wherein the dehydration
catalyst is an oxide of a heavy rare earth element. In another
aspect, there is provided a method for producing a heat transfer
fluid, the method comprising: preparing a diaryl ether by
contacting an aromatic alcohol compound with a dehydration
catalyst, wherein the dehydration catalyst is an oxide of a heavy
rare earth element; isolating the diaryl ether from the dehydration
catalyst; and mixing the isolated diaryl ether with biphenyl,
wherein the mixture forms a eutectic mixture.
DETAILED DESCRIPTION
[0010] Unless otherwise indicated, numeric ranges, for instance as
in "from 2 to 10," are inclusive of the numbers defining the range
(e.g., 2 and 10).
[0011] Unless otherwise indicated, ratios, percentages, parts, and
the like are by weight.
[0012] As noted above, in one aspect the invention provides a
method for producing a diaryl ether by dehydrating an aromatic
alcohol compound over an oxide of a heavy rare earth element. It
has been discovered that such catalysts exhibit high selectivity
for the desired diaryl ether compounds with relatively low
formation of undesirable byproducts. For instance, as demonstrated
by the examples, in the synthesis of diphenyl oxide from phenol, a
selectivity for the DPO of 50% or greater may be achieved. In some
embodiments, a selectivity of 80% or greater may be achieved. In
some embodiments, a selectivity of 90% or greater, or alternatively
95% or greater is possible.
[0013] In addition to being highly selective, the catalysts are
further advantaged because they are non-radioactive, thus
eliminating the safety and environmental issues, as well as higher
costs, associated with the handling of radioactive materials, such
as the thoria catalysts of the prior art.
[0014] The dehydration catalyst of the invention comprises an oxide
of a heavy rare earth element. By a "heavy rare earth element" is
meant terbium, dysprosium, holmium, erbium, thulium, ytterbium,
lutetium, or mixtures thereof. By "oxide of heavy rare earth
element" is meant a compound that contains at least one
oxygen-heavy rare earth element bond. Examples include, but are not
limited to, Tb.sub.2O.sub.3, Tb.sub.4O.sub.7, TbO.sub.2,
Tb.sub.6O.sub.11, Dy.sub.2O.sub.3,Ho.sub.2O.sub.3, Er.sub.2O.sub.3,
Tm.sub.2O.sub.3, Yb.sub.2O.sub.3, and Lu.sub.2O.sub.3.
[0015] In some embodiments, the catalyst is an oxide of terbium. In
some embodiments, the catalyst is an oxide of dysprosium In some
embodiments, the catalyst is an oxide of holmium. In some
embodiments, the catalyst is an oxide of erbium. In some
embodiments, the catalyst is an oxide of thulium. In some
embodiments, the catalyst is an oxide of ytterbium. In some
embodiments, the catalyst is an oxide of lutetium. Mixtures of
oxides, such as mixtures of oxides of one heavy rare earth element,
or mixtures of oxides of two or more different heavy rare earth
elements, are also encompassed by the invention.
[0016] The catalyst may optionally contain other atoms, such as
halogens, including chloride or fluoride. In some embodiments, a
preferred catalyst for use in the invention contains a heavy rare
earth element, oxygen and chlorine atoms. In some embodiments, the
catalyst comprises, in addition to the heavy rare earth element and
oxygen, chlorine in an amount of less than 40 weight percent,
alternatively 30 weight percent or less, alternatively 17 weight
percent or less, alternatively 10 weight percent or less, or
alternatively 2 weight percent or less. In some embodiments, the
catalyst comprises the chlorine in an amount of at least 0.001
weight percent, alternatively at least 0.1 weight percent,
alternatively at least 1 weight percent, or alternatively at least
2 weight percent. In some embodiments, the catalyst contains
between 1 and 17 weight percent chlorine. The chlorine is in the
form of chloride ion (Cl.sup.-). Non limiting examples of suitable
compounds may include terbium oxychloride, dysprosium oxychloride,
holmium oxychloride, erbium oxychloride, thulium oxychloride,
ytterbium oxychloride, lutetium oxychloride, or an oxide of the
heavy rare earth element also containing a chloride (e.g., from
NH.sub.4Cl, HCl, etc., or from chloride containing heavy rare earth
element precursors). By "oxychloride" is meant a compound that
contains metal-oxygen and metal-chlorine bonds. Examples further
include, again without limitation, heavy rare earth element oxide
catalysts based on chlorate oxyanions, such as hypochlorite
(ClO.sup.-); chlorite (ClO.sub.2.sup.-); chlorate
(ClO.sub.3.sup.-), perchlorate (ClO.sub.4.sup.-) where Cl is
oxidized (+2, +3, +4, +5), as well as amorphous materials.
[0017] Catalysts suitable for use in the invention may be prepared
by those skilled in the art or they may be purchased from
commercial vendors.
[0018] The catalyst may optionally contain a binder and/or matrix
material that is different from the active oxide of the heavy rare
earth element. Non-limiting examples of binders that are useful
alone or in combination include various types of hydrated alumina,
silicas and/or other inorganic oxide sols, and carbon. Upon
heating, the inorganic oxide sol, preferably having a low
viscosity, is converted into an inorganic oxide binder
component.
[0019] Where the catalyst composition contains a matrix material,
this is preferably different from the active catalyst and any
binder. Non-limiting examples of matrix materials include clays or
clay-type compositions.
[0020] The catalyst, including any binder or matrix materials, may
be unsupported or supported. Non-limiting examples of suitable
support materials include titania, alumina, zirconia, silica,
carbons, zeolites, magnesium oxide, and mixtures thereof. Where the
catalyst contains a binder, matrix or support material, the amount
of oxide of heavy rare earth element (the active component of the
catalyst) may be between 1 and 99 percent by weight based on the
total weight of the catalyst (including the oxide, and any support,
binder or matrix materials).
[0021] The catalyst may be formed into various shapes and sizes for
ease of handling. For instance, the catalyst (plus any binder,
matrix, or support) may be in the form of pellets, spheres, or
other shapes used in the industry.
[0022] Aromatic alcohol compounds suitable for use in the process
of this invention include aromatic compounds containing at least
one alcohol group and one, two, three or more aromatic moieties.
Suitable compounds include phenols and .alpha.- and
.beta.-hydroxy-substituted fused aromatic ring systems. Apart from
the hydroxy substituent, the compounds may be unsubstituted, as in
phenol or naphthol. Optionally, however, the compounds may be
further substituted with at least one alkyl group containing from 1
to about 10 carbon atoms, preferably, from 1 to 3 carbon atoms, or
substituted with at least one alternative substituent which is
inert to the dehydration coupling reaction. Suitable inert
substituents include cyano, amino, nitro, carboxylic acid (e.g.,
C.sub.0-C.sub.6-COOH), ester, C.sub.6-C.sub.12 aryl,
C.sub.2-C.sub.6 alkenyl, alkyloxy, aryloxy, and phenoxy moieties.
It is also possible for the aromatic alcohol compound to be
substituted with both an alkyl substituent and one of the
alternative inert substituents. Each of the aforementioned alkyl
substituents and/or alternative inert substituents is attached
preferably to an aromatic ring carbon atom which is located in an
ortho, meta or para position relative to the hydroxy moiety.
Optionally, the alkyl substituent may contain from 3 to 4 carbon
atoms, and in combination with a phenol or fused aromatic ring
system may form a saturated ring fused to the aromatic ring. An
acceptable feed may contain a mixture of aromatic alcohols,
including mixtures of the foregoing.
[0023] Non-limiting examples of suitable phenols include
unsubstituted phenol, m-cresol, p-cresol, 3,4-xylenol, 3,5-xylenol,
and 3,4,5-trimethylphenol. Other suitable phenols include compounds
corresponding to the above-mentioned examples except that one or
more of the methyl substituents are replaced by an ethyl, propyl or
butyl substituent. Non-limiting examples of .alpha.- and
.beta.-hydroxy-substituted fused aromatic ring systems include
.alpha.- and .beta.-naphthol and 5-tetralinol. Other non-limiting
examples of aromatic alcohols include benzenediols (catechol,
resorcinol or hydroquinone), o-cresol, o-phenylphenol,
m-phenylphenol or p-phenylphenol. One skilled in the art may find
other phenols and .alpha.- and .beta.-hydroxy-substituted fused
aromatic ring systems which are also suitable for the purposes of
this invention. Preferably, the aromatic alcohol is unsubstituted
phenol or a substituted phenol wherein the substituent is methyl,
ethyl or hydroxyl. More preferably, the aromatic alcohol is
unsubstituted phenol, cresol or a benzenediol. Most preferably, the
aromatic alcohol is unsubstituted phenol.
[0024] According to the method of the invention for preparing a
diaryl ether, a dehydration catalyst as described herein is
contacted with the aromatic alcohol compound. The contacting of the
catalyst with the aromatic alcohol compound is carried out under
reaction conditions such that the diaryl ether is formed.
[0025] The catalyst is contacted with the aromatic alcohol compound
either in the gas phase or in the liquid phase. In addition, the
aromatic alcohol may be diluted with a diluent or it may be neat.
Suitable diluents include, without limitation, nitrogen, argon,
water vapor, water, oxygen or hydrogen. When a diluent is used, the
concentration of the aromatic alcohol compound may be, for
instance, 1 volume percent or greater and less than 100 volume
percent.
[0026] In a preferred embodiment, the aromatic alcohol is contacted
with the catalyst in the gas phase. Typically, the aromatic alcohol
is introduced into a reactor containing the catalyst at elevated
temperature, for instance, between 200 and 800.degree. C.,
alternatively between 300 and 600.degree. C., alternatively between
400 and 600.degree. C., or alternatively between 450 and
550.degree. C. The reaction may be conducted at atmospheric
pressure, under reduced pressure, or at elevated pressure such as
up to 5000 psi. In some embodiments, atmospheric pressure or
slightly above (e.g., up to about 50 psi) is preferred. In some
embodiments, the gas flow rate of the aromatic alcohol over the
catalyst (weighted hourly space velocity or WHSV) is from 0.01 to
100 grams per hour per gram (g/gh). In some embodiments, WHSV is
from 0.1 to 20 g/gh, alternatively 0.1 to 5 g/gh, or alternatively
0.1 to 1 g/gh.
[0027] In some embodiments, it may be useful to subject the reactor
to startup conditions which may provide various benefits, such as
prolonging catalyst life. Suitable startup condition include, for
example, exposing the catalyst to dilute amounts of the aromatic
alcohol at lower temperature before changing to full operating
conditions as described above and demonstrated by the examples.
[0028] Following the reaction, the diaryl ether product is
recovered from the catalyst and optionally further purified.
Unreacted alcohol and other reaction by-products may be separated
using methods known in the art. Such methods include but are not
limited to distillation, crystal refining, simulated moving bed
technique or a combination thereof.
[0029] In some embodiments, the diaryl ether prepared by the
process of the invention is diphenyl oxide (DPO). Other diaryl
ether compounds that may be prepared by the process of the
invention include, without limitation, compounds containing at
least one ether functionality whereby two aryl moieties are
connected by an oxygen atom (Ar--O--Ar'), including polyaryl
compounds and compounds prepared from the aromatic alcohols
described above. Specific examples include, but are not limited to,
phenoxytoluene isomers, including 3-phenoxytoluene, ditolyl ether
isomers, polyphenyl ethers (PPEs), biphenylphenyl ether isomers and
naphthyl phenyl ethers.
[0030] The diaryl ethers prepared by the invention are useful in a
variety of applications, including as high temperature solvents, as
intermediates in preparing flame retardants and surfactants, and as
components in heat transfer fluids. Furthermore, certain diaryl
ethers prepared by the invention are useful as high performance
lubricants and as intermediates in preparing pyrethroid
insecticides.
[0031] In some embodiments, a preferred use of the diaryl ether is
in high temperature heat transfer fluids. High temperature heat
transfer fluids may be prepared by making the diaryl ether
according to the process described above and then mixing the diaryl
ether with biphenyl. The amounts necessary to provide a suitable
fluid can be readily determined by a person with ordinary skill in
the art. For diphenyl oxide and biphenyl, the amount of DPO may be,
for instance, from 70 to 75 weight percent based on the total
weight of the DPO and biphenyl. A preferred amount of DPO is that
required to form a eutectic mixture with the biphenyl, which is
about 73.5 weight percent based on the total weight of the DPO and
biphenyl.
[0032] Some embodiments of the invention will now be described in
detail in the following Examples.
EXAMPLES
Example 1
[0033] Holmium(III) oxide is used for the conversion of phenol to
diphenyl oxide (DPO). The powder is pressed and sieved to obtain
particles that are between 0.60 mm and 0.85 mm in diameter. The
particles are loaded into an electrically heated stainless steel
reactor tube and heated to the reaction temperature with nitrogen
flowing through the tube. After the reaction temperature is
reached, vapor-phase phenol is passed through the reactor tube. The
conversion of phenol is carried out at a weighted hourly space
velocities of 1 (WHSV=gram phenol/gram catalyst-hour) and at
500.degree. C. Test conditions and results are shown in Table
1.
TABLE-US-00001 TABLE 1 Conversion Selectivity [mol. %] [mol. %]
Diphenyl Test Conditions phenol Oxide OPP DBF O-BIPPE M-BIPPE
P-BIPPE T = 500.degree. C. 0.11% 48.63% 0.90% 50.47% 0.00% 0.00%
0.00% Feed: 33% PhOH, 67% N2 ToS = 1 hrs WHSV 1 hr.sup.-1 T =
500.degree. C. 0.09% 48.97% 0.56% 50.47% 0.00% 0.00% 0.00% Feed:
33% PhOH, 67% N2 ToS = 2 hrs WHSV 1 hr.sup.-1 T = 500.degree. C.
0.06% 51.51% 0.20% 48.29% 0.00% 0.00% 0.00% Feed: 33% PhOH, 67% N2
ToS = 5 hrs WHSV 1 hr.sup.-1 OPP: orthophenylphenol DBF:
dibenzofuran O-BIPPE: ortho-biphenylphenyl ether M-BIPPE:
meta-biphenylphenyl ether P-BIPPE: para-biphenylphenyl ether PhOH:
phenol N2: nitrogen ToS: time on stream (ToS = 0 hours defined at
start of phenol flow)
Example 2
[0034] The synthesis of the chlorided holmium oxide
(Cl--Ho.sub.2O.sub.3) is carried out by a thermal decomposition of
HoCl.sub.3.6H.sub.2O. Thus, a sample of the powdered precursor
(approximately 10 g) is calcined in air in a static calcination
oven under the following temperature protocol: ramp 1.41.degree.
C./min to 550.degree. C., dwell 3 hours at 550.degree. C., cool
down to room temperature. The chlorine content of the catalyst is
assayed by XRF to 13.58 wt. % chlorine. The XRD data showed the
presence of holmium oxychloride phases.
[0035] The catalyst is used in the dehydration of phenol. The
powder is pressed and sieved to obtain particles that are between
0.60 mm and 0.85 mm in diameter. The particles are loaded into an
electrically heated stainless steel reactor tube and heated to the
reaction temperature with nitrogen flowing through the tube. After
the reaction temperature is reached, vapor-phase phenol is passed
through the reactor tube. The conversion of phenol is carried out
at a weighted hourly space velocities of 1 (WHSV=gram phenol/gram
catalysthour) and at 500.degree. C. Test conditions and results are
shown in Table 2.
TABLE-US-00002 TABLE 2 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 1.23% 92.68% 0.31% 7.01% 0.00% 0.00% 0.00% Feed:
PhOH ToS = 2.25 hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 1.36%
91.33% 0.31% 8.37% 0.00% 0.00% 0.00% Feed: PhOH ToS = 3.25 hrs WHSV
1 hr.sup.-1 T = 500.degree. C. 1.57% 88.91% 0.17% 10.91% 0.00%
0.00% 0.00% Feed: PhOH ToS = 4.25 hrs WHSV 1 hr.sup.-1 T =
500.degree. C. 1.45% 87.46% 0.40% 12.14% 0.00% 0.00% 0.00% Feed:
PhOH ToS = 5.5 hrs WHSV 1 hr.sup.-1
Example 3
[0036] A 1M DyClhd 3 solution, prepared by dissolving 18.849 g
DyCl.sub.3 in 50 mL DI H.sub.2O, is added dropwise along with
tetrapropylammonium hydroxide (76.261 g, from a 40 wt % TPAOH
solution) over 15 min into a 600 mL beaker containing an initial
100 mL DI H.sub.2O. The solution is stirred at 500 rpm on magnetic
stir plate with a 3 inch stir bar. The resulting precipitate is
allowed to age in solution for 1 h with stirring, after which it is
centrifuged at 5000 rpm for 10 min. The decanted precipitate is
placed into an oven, dried at 120.degree. C. for 4 h and calcined
at 500.degree. C. for 4 h with a ramp rate of 5.degree. C./min to
yield 8.6 g of product.
Example 4
[0037] Catalytic evaluation of the catalyst from Example 3 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 3.
TABLE-US-00003 TABLE 3 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 8.30% 96.11% 0.01% 3.61% 0.00% 0.14% 0.14% Feed:
PhOH ToS = 1.25 hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 11.74%
97.58% 0.10% 2.14% 0.00% 0.08% 0.09% Feed: PhOH ToS = 2.25 hrs WHSV
1 hr.sup.-1 T = 500.degree. C. 6.36% 96.68% 0.25% 2.79% 0.00% 0.11%
0.16% Feed: PhOH ToS = 3.75 hrs WHSV 1 hr.sup.-1 T = 500.degree. C.
11.88% 95.96% 0.10% 3.63% 0.04% 0.09% 0.19% Feed: PhOH ToS = 4.75
hrs WHSV 1 hr.sup.-1
Example 5
[0038] A 1M YbCl.sub.3 solution, prepared by dissolving 19.387 g
YbCl.sub.3 in 50 mL DI H.sub.2O, is added dropwise along with
tetrapropylammonium hydroxide (76.265 g, from a 40 wt % TPAOH
solution) over 15 min into a 600 mL beaker containing an initial
100 mL DI H.sub.2O. The solution is stirred at 500 rpm on magnetic
stir plate with a 3 inch stir bar. The resulting precipitate is
allowed to age in solution for 1 h with stirring, after which it is
centrifuged at 5000 rpm for 10 min. The decanted precipitate is
placed into an oven, dried at 120.degree. C. for 4 h and calcined
at 500.degree. C. for 4 h with a ramp rate of 5.degree. C./min to
yield 9 g of product.
Example 6
[0039] Catalytic evaluation of the catalyst from Example 5 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 4.
TABLE-US-00004 TABLE 4 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 19.76% 97.39% 0.15% 2.18% 0.02% 0.19% 0.07%
Feed: PhOH ToS = 1.5 hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 22.20%
97.53% 0.06% 2.20% 0.02% 0.14% 0.06% Feed: PhOH ToS = 2.5 hrs WHSV
1 hr.sup.-1 T = 500.degree. C. 22.29% 97.55% 0.10% 2.10% 0.04%
0.14% 0.06% Feed: PhOH ToS = 3 hrs WHSV 1 hr.sup.-1
[0040] Example 7
[0041] A 1M ErCl.sub.3 solution, prepared by dissolving 15.272 g
ErCl.sub.3 in 40 mL DI H.sub.2O, is added dropwise along with
tetrapropylammonium hydroxide (61.030 g, from a 40 wt % TPAOH
solution) over 15 min into a 600 mL beaker containing an initial
100 mL DI H.sub.2O.
[0042] The solution is stirred at 500 rpm on magnetic stir plate
with a 3 inch stir bar. The resulting precipitate is allowed to age
in solution for 1 h with stirring, after which it is centrifuged at
5000 rpm for 10 min. The decanted precipitate is placed into an
oven, dried at 120.degree. C. for 4 h and calcined at 500.degree.
C. for 4 h with a ramp rate of 5.degree. C./min to yield 7.4 g of
product.
Example 8
[0043] Catalytic evaluation of the catalyst from Example 7 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 5.
TABLE-US-00005 TABLE 5 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 23.67% 97.71% 0.14% 1.99% 0.02% 0.10% 0.04%
Feed: PhOH ToS = 4.5 hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 22.86%
97.75% 0.18% 1.85% 0.01% 0.15% 0.06% Feed: PhOH ToS = 5.5 hrs WHSV
1 hr.sup.-1
Example 9
[0044] A 1M HoCl.sub.3 solution, prepared by dissolving 11.388 g
HoCl.sub.3 in 30 mL DI H.sub.2O, is added dropwise along with
tetrapropylammonium hydroxide (45.759 g, from a 40 wt % PAOH
solution) over 15 min into a 600 mL beaker containing an initial
100 mL DI H.sub.2O. The solution is stirred at 500 rpm on magnetic
stir plate with a 3 inch stir bar. The resulting precipitate is
allowed to age in solution for 1 h with stirring, after which it is
centrifuged at 5000 rpm for 10 min. The decanted precipitate is
placed into an oven, dried at 120.degree. C. for 4 h and calcined
at 500.degree. C. for 4 h with a ramp rate of 5.degree. C./min to
yield 5 g of product.
Example 10
[0045] Catalytic evaluation of the catalyst from Example 9 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 6.
TABLE-US-00006 TABLE 6 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 12.22% 97.77% 0.21% 1.87% 0.02% 0.07% 0.07%
Feed: PhOH ToS = 1.75 hrs WHSV 1 hr.sup.-1 T = 500.degree. C.
12.73% 97.90% 0.28% 1.63% 0.00% 0.13% 0.07% Feed: PhOH ToS = 3.75
hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 12.34% 97.95% 0.24% 1.61%
0.02% 0.11% 0.05% Feed: PhOH ToS = 5 hrs WHSV 1 hr.sup.-1 T =
500.degree. C. 12.02% 97.88% 0.12% 1.82% 0.00% 0.11% 0.07% Feed:
PhOH ToS = 7 hrs WHSV 1 hr.sup.-1
Example 11
[0046] The synthesis of supported holmium oxychloride is carried
out via an incipient wetness impregnation of gamma alumina.
Precursors:
[0047] Support: gamma alumina (Saint-Gobain NorPro, 30-60 mesh
size, BET=178.9 m.sup.2/g) that exhibits an incipient wetness
condition of approximately 0.75 mL per 1 g. Solution: holmium(III)
chloride hexahydrate (HoCl.sub.3.6H.sub.2O) and deionized water (DI
water), prepared to c=0.7500 mol/L
Synthesis:
[0048] 3.75 mL of the solution is added dropwise to 5 g of the
support at ambient conditions under vigorous shaking using a shaker
plate. The impregnated material is then dried at 150.degree. C. for
1 h, and the impregnation procedure is repeated three more times
(total of 4.times.3.75 mL used for 5 g of carrier) to achieve a
high loading of holmium inside the pores of the carrier. The
preparation is finished off by calcining the impregnated material
in a static air calcination oven using the following protocol: ramp
1.degree. C./min; dwell at T=550.degree. C. for 3 hrs, cool down to
room temperature. The chlorine content of the catalyst is assayed
by XRF to 4.48 wt. % chlorine.
Example 12
[0049] Catalytic evaluation of the catalyst from Example 11 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 7.
TABLE-US-00007 TABLE 7 Conversion Selectivity [mol. %] [mol. %]
Diphenyl Test Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE
P-BIPPE T = 500.degree. C. 4.57% 82.05% 2.32% 15.22% 0.06% 0.17%
0.19% Feed: PhOH ToS = 1.25 hrs WHSV 1 hr.sup.-1 T = 500.degree. C.
4.05% 83.70% 1.21% 14.45% 0.08% 0.17% 0.39% Feed: PhOH ToS = 2.25
hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 4.03% 84.56% 2.16% 12.35%
0.08% 0.15% 0.70% Feed: PhOH ToS = 3.5 hrs WHSV 1 hr.sup.-1 T =
500.degree. C. 3.20% 86.04% 2.86% 10.42% 0.09% 0.00% 0.58% Feed:
PhOH ToS = 4.25 hrs WHSV 1 hr.sup.-1
Example 13
[0050] The synthesis of supported holmium oxychloride is carried
out via an incipient wetness impregnation of amorphous silica.
Precursors:
[0051] Support: amorphous silica (WR Grace-Davison 57, 30-60 mesh
size, BET=275.3 m.sup.2/g) that exhibits an incipient wetness
condition of approximately 0.90 mL per 1 g. Solution: holmium(III)
chloride hexahydrate (HoCl.sub.3.6 H.sub.2O) and deionized water
(DI water), prepared to c=1.25 mol/L.
Synthesis:
[0052] 4.5 mL of the solution is added dropwise to 5 g of the
support at ambient conditions under vigorous shaking using a shaker
plate. The impregnated material is then dried at 150.degree. C. for
1 h, and the preparation is finished off by calcining the
impregnated material in a static air calcination oven using the
following protocol: ramp 1.degree. C./min; dwell at T=550.degree.
C. for 3 hrs, step down to room temperature. The chlorine content
of the catalyst is assayed by XRF to 2.02 wt. % chlorine.
Example 14
[0053] Catalytic evaluation of the catalyst from Example 13 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 8.
TABLE-US-00008 TABLE 8 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 1.91% 53.78% 0.24% 45.76% 0.00% 0.00% 0.22%
Feed: PhOH ToS = 1.5 hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 1.86%
52.16% 4.21% 43.27% 0.00% 0.00% 0.36% Feed: PhOH ToS = 2.25 hrs
WHSV 1 hr.sup.-1 T = 500.degree. C. 1.49% 52.09% 7.17% 40.36% 0.00%
0.00% 0.39% Feed: PhOH ToS = 3 hrs WHSV 1 hr.sup.-1 T = 500.degree.
C. 1.50% 51.08% 1.44% 47.09% 0.00% 0.00% 0.39% Feed: PhOH ToS =
3.75 hrs WHSV 1 hr.sup.-1
Example 15
[0054] A preparation of a holmium oxychloride sample is
accomplished by setting up a 2-L 3-necked flask with two air-tight
addition funnels, pH meter, and argon bubbling into 750 ml of DI
H.sub.2O at a flow rate of 300 sccm. After purging with argon, an
aqueous solution of HoCl.sub.3, prepared by dissolving 62.6 g
HoCl.sub.3 in 165 mL DI H.sub.2O, is added dropwise over 0.5 hours
along with a controlled addition of aqueous ammonia to maintain the
pH constant at 9. The resulting suspension is added to a nitrogen
purged centrifuge container, capped, and centrifuged to separate
the precipitate from the solution. The liquid is poured off and the
containers are placed in a vacuum oven at 80.degree. C. for 16
hours. The dried sample is transferred into a purged quartz tube
within a tube furnace where it is treated in flowing 1% oxygen in
helium mixture for 5 minutes at room temperature, thermally treated
at 500.degree. C. for 3 h, and then cooled to room temperature in
flowing nitrogen.
Example 16
[0055] Catalytic evaluation of the catalyst from Example 15 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 9.
TABLE-US-00009 TABLE 9 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 17.92% 96.73% 0.58% 2.53% 0.01% 0.14% 0.00%
Feed: PhOH ToS = 1.5 hrs WHSV 1 hr.sup.-1 T = 500.degree. C. 14.96%
96.44% 0.36% 3.01% 0.02% 0.17% 0.00% Feed: PhOH ToS = 2.5 hrs WHSV
1 hr.sup.-1 T = 500.degree. C. 12.90% 96.34% 0.66% 2.91% 0.02%
0.05% 0.02% Feed: PhOH ToS = 3.75 hrs WHSV 1 hr.sup.-1 T =
500.degree. C. 11.21% 96.15% 0.84% 2.88% 0.00% 0.09% 0.05% Feed:
PhOH ToS = 4.75 hrs WHSV 1 hr.sup.-1
Example 17
[0056] Preparation of 16 wt % Ho supported on ZrO.sub.2 via
incipient wetness impregnation. Prior to the impregnation process a
hydrous ZrO.sub.2 support with BET surface area of 323 m.sup.2/g is
pre-dried at 120.degree. C. for 4 hours in static air. 16 wt % Ho
on ZrO.sub.2 catalyst is prepared by two step incipient wetness
impregnation of the treated ZrO.sub.2 at ambient temperature. A
glass beaker is charged with 5 g of pre-dried ZrO.sub.2. A 10-ml
graduated cylinder is loaded with 0.9207 g of HoCl.sub.3.6H.sub.2O
to yield 8 wt % of Ho and with 1.2 ml of H.sub.2O. The support is
impregnated with aqueous solution of holmium being added to the
ZrO.sub.2 in small fractions. After each addition, the support is
agitated to break up clumps and uniformly disperse holmium
throughout the carrier material. After the first step impregnation,
the sample is dried at 110.degree. C. for 4 hours. In the next step
the whole process is repeated using 0.9159 g of
HoCl.sub.3.6H.sub.2O to again yield 8 wt % of Ho with 1.2 ml of
H.sub.2O. The impregnated sample is then treated at 110.degree. C.
for 4 hours in flowing air and then at 600.degree. C. for an
additional 4 hours a 5.degree. C./min ramp.
Example 18
[0057] Catalytic evaluation of the catalyst from Example 17 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 10.
TABLE-US-00010 TABLE 10 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 2.73% 93.82% 0.05% 6.13% 0.00% 0.00% 0.00% Feed:
PhOH ToS = 1 hr WHSV 1 hr.sup.-1 T = 500.degree. C. 5.59% 86.86%
1.73% 11.42% 0.00% 0.00% 0.00% Feed: PhOH ToS = 2.75 hrs WHSV 1
hr.sup.-1 T = 500.degree. C. 4.01% 84.15% 3.12% 12.72% 0.00% 0.00%
0.00% Feed: PhOH ToS = 4 hrs WHSV 1 hr.sup.-1 T = 500.degree. C.
3.28% 83.79% 1.37% 14.84% 0.00% 0.00% 0.00% Feed: PhOH ToS = 5 hrs
WHSV 1 hr.sup.-1
Example 19
Preparation of 15 wt % Yb Supported on ZrO.sub.2 via Incipient
Wetness Impregnation.
Synthesis:
[0058] Prior to the impregnation process a hydrous ZrO.sub.2
support with BET surface area of 323 m.sup.2/g is pre-dried at
120.degree. C. for 4 hours in static air. 15 wt % Yb on ZrO.sub.2
catalyst is prepared by two step incipient wetness impregnation of
the treated ZrO.sub.2 at ambient temperature. A glass beaker is
charged with 5 g of pre-dried ZrO.sub.2. A 10-ml graduated cylinder
is loaded with a 0.8405 g of YbCl.sub.3.6H.sub.2O to yield 7.5 wt %
of Yb and with 1.2 ml of H.sub.2O. The support is impregnated with
aqueous solution of ytterbium being added to the ZrO.sub.2 in small
fractions. After each addition, the support is agitated to break up
clumps and uniformly disperse ytterbium throughout the carrier
material. After the first step impregnation, the sample is dried at
110.degree. C. for 4 hours. In the next step the whole process is
repeated using 0.8370 g of YbCl.sub.3.6H.sub.2O to again yield 7.5
wt % of Yb with 1.2 ml of H.sub.2O. The impregnated sample is then
treated at 110.degree. C. for 4 hours in flowing air and then at
600.degree. C. for an additional 4 hours at 5.degree. C./min
ramp.
Example 20
[0059] Catalytic evaluation of the catalyst from Example 19 is
carried out using a similar procedure as in Example 2. Test
conditions and results are shown in Table 11.
TABLE-US-00011 TABLE 11 Conversion Selectivity [mol. %] Test [mol.
%] Diphenyl Conditions Phenol Oxide OPP DBF O-BIPPE M-BIPPE P-BIPPE
T = 500.degree. C. 6.05% 71.96% 6.61% 20.74% 0.06% 0.64% 0.00%
Feed: PhOH ToS = 1 hr WHSV 1 hr.sup.-1 T = 500.degree. C. 4.08%
73.59% 6.35% 17.09% 0.00% 0.99% 1.98% Feed: PhOH ToS = 2.75 hrs
WHSV 1 hr.sup.-1 T = 500.degree. C. 4.03% 71.42% 4.67% 21.49% 0.00%
0.72% 1.69% Feed: PhOH ToS = 4 hrs WHSV 1 hr.sup.-1 T = 500.degree.
C. 2.97% 73.63% 5.57% 17.87% 0.00% 0.78% 2.15% Feed: PhOH ToS = 5
hrs WHSV 1 hr.sup.-1
* * * * *