U.S. patent application number 11/703972 was filed with the patent office on 2007-07-26 for polymeric imides as pour point depressant additives for oil compositions.
This patent application is currently assigned to Akzo Nobel N.V.. Invention is credited to Rodney Lee Cravey, Stephen L. Mead, Mohammad A. Rahman.
Application Number | 20070173419 11/703972 |
Document ID | / |
Family ID | 34967327 |
Filed Date | 2007-07-26 |
United States Patent
Application |
20070173419 |
Kind Code |
A1 |
Mead; Stephen L. ; et
al. |
July 26, 2007 |
Polymeric imides as pour point depressant additives for oil
compositions
Abstract
The present invention generally relates to oil compositions,
primarily to fuel oil and petroleum compositions produced there
from susceptible to wax formation at low temperatures, to polymeric
imides for use with such fuel oil compositions, and to methods for
their manufacture.
Inventors: |
Mead; Stephen L.; (Danbury,
CT) ; Cravey; Rodney Lee; (Manvel, TX) ;
Rahman; Mohammad A.; (Pomona, NY) |
Correspondence
Address: |
AKZO NOBEL INC.
INTELLECTUAL PROPERTY DEPARTMENT
120 WHITE PLAINS ROAD 3RD FLOOR
TARRTOWN
NY
10591
US
|
Assignee: |
Akzo Nobel N.V.
Arnhem
NL
|
Family ID: |
34967327 |
Appl. No.: |
11/703972 |
Filed: |
February 8, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11547349 |
Sep 29, 2006 |
|
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PCT/EP05/03638 |
Apr 5, 2005 |
|
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11703972 |
Feb 8, 2007 |
|
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60559850 |
Apr 6, 2004 |
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Current U.S.
Class: |
508/287 |
Current CPC
Class: |
C10L 10/14 20130101;
C10L 10/16 20130101; C10M 2207/401 20130101; C10L 1/2364 20130101;
C10M 2205/028 20130101; C10L 1/232 20130101; C10L 1/224 20130101;
C10M 2207/2805 20130101; C10M 2203/1006 20130101; C10N 2030/08
20130101; C10M 149/06 20130101; C10M 2205/028 20130101; C10M
2209/086 20130101; C10N 2060/09 20200501; C10M 2205/028 20130101;
C10M 2209/086 20130101; C10N 2060/09 20200501 |
Class at
Publication: |
508/287 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Claims
1. An oil composition having improved low temperature properties
comprising oil and an effective amount of a pour point depressant
additive composition that comprises at least one pour point
depressant additive of the formulae I ##STR5## wherein each R.sup.1
is independently selected from H or a hydrocarbyl group having from
1 to 50 carbon atoms, R.sup.2, R.sup.3 and R.sup.4 are each
independently selected from hydrogen or a hydrocarbyl groups
containing from 1 up to 50 carbon atoms, m is an integer of from 1
to 50, n is an integer of from 0 to 50, and each R.sup.5 is
independently selected from O and NH.
2. The composition of claim 1 wherein R.sup.1 is H or a
C.sub.6-C.sub.30 saturated or unsaturated, substituted, or
unsubstituted alkyl group, R.sup.2 and R.sup.3 are each
independently selected from C.sub.6-C.sub.30 saturated or
unsaturated, substituted, or unsubstituted alkyl groups; m is an
integer of from 1 to 30 and n is an integer of from 1-30.
3. The composition of claim 1 wherein R.sup.1 is H or a
C.sub.8-C.sub.24 saturated or unsaturated, substituted, or
unsubstituted alkyl group R.sup.2 and R.sup.3 are each
independently selected from C.sub.8-C.sub.24 saturated or
unsaturated, substituted or unsubstituted alkyl groups; m is an
integer of from 1 to 30 and n is an integer of from 1-20.
4. The composition of claim 1 wherein said oil is selected from the
group consisting of crude oil, fuel oil, castor oil, fish oil,
biodiesel and mixtures thereof.
5. The composition of claim 1 wherein said oil composition having
improved low temperature properties comprises 0.0001% to 1% by
weight of the pour point depressant additive composition of the
invention, based on the weight of oil.
6. The composition of claim 1 wherein said oil composition having
improved low temperature properties comprises 0.0001 to 1.0% by
weight of the pour point depressant additive composition of the
invention, based on the weight of oil.
7. The composition of claim 1 wherein said oil composition having
improved low temperature properties comprises 0.0001 to 1.0% by
weight of the pour point depressant additive composition of the
invention, based on the weight of oil.
8. The composition of claim 1 wherein said oil is crude oil or fuel
oil.
9. The composition of claim 1 wherein the oil has a wax content of
0.1 to 20% by weight, measured at 10 degrees below wax appearance
temperature.
10. The composition of claim 1 one or more other co-additives such
as known in the art, for example the following: detergents,
particulate emission reducers, storage stabilizers, antioxidants,
corrosion inhibitors, dehazers, demulsifiers, antifoaming agents,
cetane improvers, cosolvents, package compatibilizers, and
lubricity additives.
11. A pour point depressant additive concentrate that comprises at
least one pour point depressant additive of the formula: ##STR6##
wherein each R.sup.1 is independently selected from H or a
hydrocarbyl group having from 1 to 50 carbon atoms, R.sup.2,
R.sup.3 and R.sup.4 are each independently selected from hydrogen
or a hydrocarbyl groups containing from 1 up to 50 carbon atoms, m
is an integer of from 1 to 50, n is an integer of from 0 to 50, and
each R.sup.5 is independently selected from O and NH.
12. The concentrate of claim 11 wherein R.sup.1 is H or a
C.sub.6-C.sub.30 saturated or unsaturated, substituted or
unsubstituted alkyl group R.sup.2 and R.sup.3 are each
independently selected from C.sub.6-C.sub.30 saturated or
unsaturated, substituted or unsubstituted alkyl groups; m is an
integer of from 1 to 30 and n is an integer of from 1-30.
13. The concentrate of claim 11 wherein R.sup.1 is H or a
C.sub.8-C.sub.24 saturated or unsaturated, substituted or
unsubstituted alkyl group, R.sup.2 and R.sup.3 are each
independently selected from C.sub.8-C.sub.24 saturated or
unsaturated, substituted or unsubstituted alkyl groups; m is an
integer of from 1 to 30 and n is an integer of from 1-20.
14. The concentrate of claim 11 wherein said solvent an organic
solvent.
15. The concentrate of claim 11 wherein said organic solvent is
selected from the group consisting of naphtha, kerosene, diesel,
heater oil; aromatic hydrocarbon fraction, alcohols, esters,
hexane, pentane, isoparaffins and mixtures thereof.
16. The concentrate of claim 11 that contains between 3 and 75% of
said pour point depressant additive.
17. The concentrate of claim 16 that contains between 10 and 65%,
of the pour point depressant additive.
18. A method of improving the low temperature flow properties of
oil which comprises adding to said oil an effective amount of a
pour point depressant additive composition that comprises at least
one pour point depressant additive of the formula: ##STR7## wherein
each R.sup.1 is independently selected from H or a hydrocarbyl
group having from 1 to 50 carbon atoms, R.sup.2, R.sup.3 and
R.sup.4 are each independently selected from hydrogen or a
hydrocarbyl groups containing from 1 up to 50 carbon atoms, m is an
integer of from 1 to 50, n is an integer of from 0 to 50, and each
R.sup.5 is independently selected from O and NH.
19. The method of claim 18 wherein R.sup.1 is H or a
C.sub.6-C.sub.30 saturated or unsaturated, substituted or
unsubstituted alkyl group, R.sup.2 and R.sup.3 are each
independently selected from C.sub.6-C.sub.30 saturated or
unsaturated, substituted or unsubstituted alkyl groups; m is an
integer of from 1 to 50, and n is an integer of from 1-30.
20. The method of claim 19 wherein R.sup.1 is H or a
C.sub.8-C.sub.24 saturated or unsaturated, substituted or
unsubstituted alkyl group, R.sup.2 and R.sup.3 are each
independently selected from C.sub.8-C.sub.24 saturated or
unsaturated, substituted or unsubstituted alkyl groups; m is an
integer of from 1 to 50 and n is an integer of from 1-20.
21. The method of claim 18 wherein said oil is selected from the
group consisting of crude oil, fuel oil, castor oil, fish oils,
biodiesel and mixtures thereof.
22. The method of claim 18 wherein 0.0005% to 1% by weight of the
pour point depressant additive composition, based on the weight of
oil, is added.
23. The method of claim 1 wherein said oil is crude oil or fuel
oil.
Description
[0001] This is a continuation-in-part of U.S. application Ser. No.
11/547349, which is based on International application number
PCT/EP2005/003638 filed on Apr. 5, 2005.
FIELD OF THE INVENTION
[0002] The present invention generally relates to polymeric imides
useful as pour point depressants and their use in providing oils
with improved low temperature flow properties.
BACKGROUND OF THE INVENTION
[0003] The present invention generally relates to oil compositions,
primarily to fuel oil and petroleum compositions produced there
from susceptible to wax formation at low temperatures, to polymeric
imides for use with such fuel oil compositions, and to methods for
their manufacture.
[0004] Fuel oils and/or petroleum products, whether derived from
petroleum or vegetable sources, contain components, e.g.,
paraffins, alkanes, etc. that at low temperature tend to
precipitate as large crystals or spherulites of wax in such a way
as to form a gel structure which causes the oil to lose its ability
to flow. The lowest temperature at which the fuel will still flow
is known as the pour point.
[0005] As the temperature of the fuel falls and approaches the pour
point, difficulties arise in transporting the fuel through lines
and pumps. Further, the wax crystals tend to plug fuel lines,
screens, and filters at temperatures above the pour point. These
problems are well recognized in the art, and various additives have
been proposed, many of which are in commercial use, for depressing
the pour point of fuel oils. Similarly, other additives have been
proposed and are in commercial use for reducing the size and
changing the shape of the wax crystals that do form. Smaller size
crystals are desirable since they are less likely to clog a filter.
The wax from a diesel fuel, which is primarily an alkane wax,
crystallizes as platelets; certain additives inhibit this and cause
the wax to adopt an acicular habit, the resulting needles being
more likely to pass through a filter than are platelets. The
additives may also suspend in the fuel the crystals that have
formed, the resulting reduced settling also assisting in prevention
of blockages.
[0006] Effective wax crystal modification (as measured by cold
filter plugging point (CFPP),(ASTM D97-66) and other operability
tests, as well as simulated and field performance are known in the
art. However, there is a continual need in the art to produce more
effective polymers giving improved performance.
[0007] Surprisingly, the present inventors have found more
effective and economical additives. In particular, applicant has
found that certain polymeric imides can effectively and
economically be employed as pour point depressants for various
grades of crude and fuel oil.
SUMMARY OF THE INVENTION
[0008] The present invention generally relates to an oil
composition having improved low temperature properties comprising
oil and an effective amount of a pour point depressant additive
composition that comprises at least one pour point depressant
additive of the following formula. ##STR1## wherein R.sup.1 is H or
a hydrocarbyl group having from 1 to 50 carbon atoms, R.sup.2,
R.sup.3 and R.sup.4 are independently selected from hydrogen or
hydrocarbyl groups containing from 1 up to 50 carbon atoms, m is an
integer of from 1 to 50, n is an integer of from 0 to 50, and each
R.sup.5 groups may be any possible combination of O and NH groups
on the polymer.
[0009] The invention also relates to a pour point depressant
additive composition, a pour point depressant additive concentrate
composition and a method of improving the low temperature flow
properties of a composition that comprises in major part at least
one oil, said method comprising admixture of the composition
comprising said at least one oil with an effective amount of the
aforementioned pour point depressant additive and/or additive
concentrate.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention generally relates to a pour point
depressant additive composition that comprises at least one
polymeric imide as hereinafter described.
[0011] In a second aspect, this invention relates to a pour point
depressant additive concentrate composition comprising the
aforementioned pour point depressant additive and a compatible
solvent thereof.
[0012] In a third aspect, the invention provides an oil composition
with improved low temperature flow properties comprising oil and an
amount of the aforementioned pour point depressant additive and/or
additive concentrate.
[0013] In a fourth embodiment the invention relates to a method of
improving the low temperature flow properties of a composition that
comprises in major part at least one oil, said method comprising
admixture of the composition comprising said at least one oil with
an effective amount of the aforementioned pour point depressant
additive and/or additive concentrate.
[0014] The pour point depressant additive of the present invention
comprises at least one polymeric imide of General Formulae I:
##STR2## wherein each R.sup.1 is H or a hydrocarbyl group having
from 1 to 50 carbon atoms, R.sup.2, R.sup.3 and R.sup.4 are
independently selected from hydrogen or hydrocarbyl groups
containing from 1 up to 50 carbon atoms, m is an integer of from 1
to 50, n is an integer of from 0 to 50 and each R.sup.5 group may
be any possible combination of O and NH groups on the polymer. The
R.sup.5 groups may exclusively be O or NH on the polymer.
[0015] As used herein the term "hydrocarbyl" refers to a group
having a carbon atoms directly attached to the rest of the molecule
and having a hydrocarbon or predominantly hydrocarbon character.
Among these, there may be mentioned hydrocarbon groups, including
aliphatic, (e.g., alkyl), alicyclic (e.g., cycloalkyl), aromatic,
aliphatic and alicyclic-substituted aromatic, and
aromatic-substituted aliphatic and alicyclic groups. Aliphatic
groups can be saturated or unsaturated. These groups may contain
non-hydrocarbon substituents provided their presence does not alter
the predominantly hydrocarbon character of the group. Examples
include keto, halo, hydroxy, nitro, cyano, alkoxy and acyl. If the
hydrocarbyl group is substituted, a single (mono) substituent is
preferred. Examples of substituted hydrocarbyl groups include
2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-ketopropyl,
ethoxyethyl, and propoxypropyl. The groups may also or
alternatively contain atoms other than carbon in a chain or ring
otherwise composed of carbon atoms. Suitable hetero atoms include,
for example, nitrogen, sulphur, and, preferably, oxygen.
Advantageously, the hydrocarbyl group contains at most 36,
preferably at most 15, more preferably at most 10 and most
preferably at most 8, carbon atoms.
[0016] In one embodiment R.sup.1 is a C.sub.6-C.sub.40 saturated or
unsaturated substituted or unsubsituted alkyl group; R.sup.2 is a
C.sub.6-C.sub.30 saturated or unsaturated substituted or
unsubsituted alkyl group; and n is an integer of from 1-30. In
another embodiment R.sup.1 is a C.sub.8-C.sub.24 saturated or
unsaturated substituted or unsubsituted alkyl group; R.sup.2 is a
C.sub.8-C.sub.24 saturated or unsaturated substituted or
unsubsituted alkyl group; and n is an integer of from 1-20. In
still another embodiment R.sup.1 is a C.sub.12-C.sub.22 saturated
or unsaturated substituted alkyl group; R.sup.2 is a
C.sub.12-C.sub.22 saturated or unsaturated substituted or
unsubsituted alkyl group; and n is an integer of from 1 -10
[0017] The products of the present invention are generally prepared
by reacting an (a) alpha olefin with (b) maleic anhydride in the
presence of a free radical initiator such as, for example,
tert-butyl peroxybenzoate (other free radical initiators useful in
the context of the present invention are known to those skilled in
the art) in order to form (c) a high molecular weight copolymer.
This copolymer is then reacted with an (d) amine to form the imide.
In order to produce high yields of the imide, reaction temperatures
of from about 220.degree. C., or higher, are preferred.
[0018] It is understood that any alpha olefin of varying carbon
chain length can be employed in order to make the products of the
invention. In one embodiment the a) alpha olefin is a
C.sub.6-C.sub.24 alpha olefin; in another embodiment it is a
C.sub.12-C.sub.24 alpha olefin, in another embodiment it is
aC.sub.20-C.sub.24 alpha olefin, and still another it is
aC.sub.24-C.sub.28 alpha olefin.
[0019] In one embodiment the high molecular weight copolymer is of
the formula: ##STR3##
[0020] The amines employable in the reaction with the high
molecular weight copolymer can be any amine commercially available
that reacts with such copolymer. Preferably, the amine is of the
formula: ##STR4## where R.sup.2 is an alkylene group of from 6 to
30 carbon atoms. Nonlimiting examples of amines suitable for use
include but are not limited to tallowamine, hydrogenated
tallowamine, cocoamine, soyamine, oleylamine, octadecylamine,
hexadecylamine, dodecylamine, 2-ethylhexylamine, dicocoamine,
ditallowamine, dehydrogenated tallowamine, didecylamine,
dioctadecylamine, N-coco-1,3-diaminopropane,
N-tallow-1,3-diaminopropane,
N,N,N-trimethyl-N-tallow-1,3-diaminopropane,
N-oleyl-1,3-diaminopropane,
N,N<N-trimethyl-N-9-octadecenyl-1,3-diaminopropane,
3-tallowalkyl-1,3-hexahydropyrimidine and mixtures thereof.
[0021] The reaction of the high molecular weight copolymer and
amine may be conducted in the presence of at least one alcohol to
yield a mixture of imides and esters on the copolymer chain.
Alcohols generally contain from 1 up to 50 carbon atoms. In one
embodiment of the invention, alcohols that can usefully be employed
include, but are not limited to methanol, ethanol, propanol,
isopropanol, butanol, isobutanol C.sub.10-C.sub.20+ alcohol blends,
C.sub.12-C-.sub.36 Guerbet alcohols, Behenyl alcohols, and mixtures
thereof. Under mild conditions it is possible to obtain a
combination of imides, amides and esters. Under milder conditions
it is possible to obtain a mixture with a majority of amide and
ester structures. In the absence of alcohols, amides and imides may
be formed exclusively.
[0022] The polymer may be made by any of the methods known in the
art, e.g., by solution polymerization with free radical initiation,
or by high pressure polymerization, conveniently carried out in an
autoclave or a tubular reactor.
[0023] In order to prepare mixtures of esters, imides and amides on
the copolymer, alcohols may be mixed with the amines at any
alcohol/amine ratio to form a mixture of imide. ester and amide.
The amount of attachment may vary from 0.1 to 2.0 moles of combined
alcohol and amine for each mole of maleic anhydride employed. The
full ester structure is then made by reacting the copolymer with
the amine/alcohol which can be run at any water-producing
temperature with or without solvent. This reaction may be run at
lower temperatures to produce more of the amide structures. At
milder conditions an amide or amide+ester may be the only products
generated . In one embodiment, examples of preferred
imides+esters+amides that can be usefully employed in the context
of the present invention include, but are not limited to
imides+esters+amides derived from the reaction maleic anhydride
with at least one of the following amines: tallowamine,
hydrogenated tallowamine, cocoamine, soyamine, oleylamine,
octadecylamine, hexadecylamine, dodecylamine, 2-ethylhexylamine,
dicocoamine, ditallowamine, dehydrogenated tallowamine,
didecylamine, dioctadecylamine, N-coco-1,3-diaminopropane,
N-tallow-1,3-diaminopropane,
N,N,N-trimethyl-N-tallow-1,3-diaminopropane,
N-oleyl-1,3-diaminopropane,
N,N<N-trimethyl-N-9-octadecenyl-1,3-diaminopropane,
3-tallowalkyl-1,3-hexahydropyrimidine and mixtures thereof in
combination with the alcohols: methanol, ethanol, propanol,
isopropanol, butanol, isobutanol C.sub.10-C.sub.20+ alcohol blends,
C.sub.12-C-.sub.36 Guerbet alcohols, Behenyl alcohols and mixtures
thereof.
[0024] As indicated above, the polymeric imides of the invention
may contain a mixture of different species. It is also within the
scope of the invention to provide a composition comprising a
mixture of two or more of said polymers.
[0025] The pour point depressant additive of the present invention
is especially useful in crude and/or fuel oils having a relatively
high wax content, e.g., a wax content of 0.1 to 20% by weight per
weight of fuel, preferably 3.0 to 4.5, such as 3.5 to 4.5% wt,
measured at 10.degree. C. below wax appearance temperature
(WAT).
[0026] The polymer is preferably soluble in the oil to the extent
of at least 10,000 ppm by weight per weight of oil at ambient
temperature. However, at least some of the additive may come out of
solution near the cloud point of the oil and function to modify the
wax crystals that form.
[0027] The pour point depressant additive of the present invention
can be employed alone, or it may be combined with other additives
for improving low temperature flowability and/or other properties,
which are in use in the art or known from the literature. The pour
point depressant additive composition may also comprise additional
cold flow improvers, including but not limited to comb polymers,
polar nitrogen compounds, compounds containing a cyclic ring
system, hydrocarbon polymer, polyoxyalkylene compounds, mixtures
thereof and the like.
[0028] Comb polymers--are polymers in which branches containing
hydrocarbyl groups are pendant from a polymer backbone, and are
discussed in "Comb-Like Polymers. Structure and Properties", N. A.
Plate and V. P. Shibaev, J. Poly. Sci. Macromolecular Revs., 8, p
117 to 253 (1974), which is incorporated herein by reference.
[0029] Generally, comb polymers have one or more long chain
hydrocarbyl branches, e.g., oxyhydrocarbyl branches, normally
having from 10 to 30 carbon atoms, pendant from a polymer backbone,
said branches being bonded directly or indirectly to the backbone.
Examples of indirect bonding include bonding via interposed atoms
or groups, which bonding can include covalent and/or electrovalent
bonding such as in a salt.
[0030] Advantageously, the comb polymer is a homopolymer or a
copolymer having at least 25 and preferably at least 40, more
preferably at least 50, molar per cent of the units of which have
side chains containing at least 6, and preferably at least 10,
atoms.
[0031] These comb polymers may be copolymers of maleic anhydride or
fumaric or itaconic acids and another ethylenically unsaturated
monomer, e.g., an alpha-olefin, including styrene, or an
unsaturated ester, for example, vinyl acetate or homopolymer of
fumaric or itaconic acids. It is preferred but not essential that
equimolar amounts of the comonomers be used although molar
proportions in the range of 2 to 1 and 1 to 2 are suitable.
Examples of olefins that may be copolymerized with e.g., maleic
anhydride, include 1-decene, 1-dodecene, 1-tetradecene,
1-hexadecene, and 1-octadecene.
[0032] The acid or anhydride group of the comb polymer may be
esterified by any suitable technique and although preferred it is
not essential that the maleic anhydride or fumaric acid be at least
50% esterified. Examples of alcohols which may be used include
n-decan-1-ol, n-dodecan-1-ol, n-tetradecan-1-ol, n-hexadecan-1-ol,
and n-octadecan-1-ol. The alcohols may also include up to one
methyl branch per chain, for example, 1-methylpentadecan 1-ol or
2-methyltridecan-1-ol. The alcohol may be a mixture of normal and
single methyl branched alcohols.
[0033] These comb polymers may especially be fumarate or itaconate
polymers and copolymers such for example as those described in
EP-A-153176, -153177 and -225688, and WO 91/16407.
[0034] Particularly preferred fumarate comb polymers are copolymers
of alkyl fumarates and vinyl acetate, in which the alkyl groups
have from 12 to 20 carbon atoms, more especially polymers in which
the alkyl groups have 14 carbon atoms or in which the alkyl groups
are a mixture of C.sub.14/C.sub.16 alkyl groups, made, for example,
by solution copolymerizing an equimolar mixture of fumaric acid and
vinyl acetate and reacting the resulting copolymer with the alcohol
or mixture of alcohols, which are preferably straight chain
alcohols. When the mixture is used it is advantageously a 1:1 by
weight mixture of normal C.sub.14 and C.sub.16 alcohols.
Furthermore, mixtures of the C.sub.14 ester with the mixed
C.sub.14/C.sub.16 ester may advantageously be used. In such
mixtures, the ratio of C.sub.14 to C.sub.14/C.sub.16 is
advantageously in the range of from 1:1 to 4:1, preferably 2:1 to
7:2, and most preferably about 3:1, by weight. The particularly
preferred comb polymers are those having a number average molecular
weight, as measured by vapor phase osmometry, of 1,000 to 100,000,
more especially 1,000 to 30,000.
[0035] Other suitable comb polymers are the polymers and copolymers
of alpha-olefins and esterified copolymers of styrene and maleic
anhydride, and esterified copolymers of styrene and fumaric acid;
mixtures of two or more comb polymers may be used in accordance
with the invention and, as indicated above, such use may be
advantageous. Other examples of comb polymers are hydrocarbon
polymers, e.g., copolymers of ethylene and at least one
alpha-olefin, the alpha-olefin preferably having at most 20 carbon
atoms, examples being n-decene-1 and n-dodecene-1. Preferably, the
number average molecular weight of such a copolymer is at least
30,000 measured by GPC. The hydrocarbon copolymers may be prepared
by methods known in the art, for example using a Ziegler type
catalyst.
[0036] Polar nitrogen compounds. Such compounds are oil-soluble
polar nitrogen compounds carrying one or more, preferably two or
more, substituents of the formula >NR.sub.13, where R.sub.13
represents a hydrocarbyl group containing 8 to 40 atoms, which
substituent or one or more of which substituents may be in the form
of a cation derived therefrom. The oil soluble polar nitrogen
compound is generally one capable of acting as a wax crystal growth
inhibitor in fuels, it comprises for example one or more of the
following compounds:
[0037] An amine salt and/or amide formed by reacting at least one
molar proportion of a hydrocarbyl-substituted amine with a molar
proportion of a hydrocarbyl acid having from 1 to 4 carboxylic acid
groups or its anhydride, the substituent(s) of formula
>NR.sub.13 being of the formula --NR.sub.13 R.sub.14 where
R.sub.13 is defined as above and R.sub.14 represents hydrogen or
R.sub.13, provided that R.sub.13 and R.sub.14 may be the same or
different, said substituents constituting part of the amine salt
and/or amide groups of the compound.
[0038] Ester/amides may be used, containing 30 to 300, preferably
50 to 150, total carbon atoms. These nitrogen compounds are
described in U.S. Pat. No. 4,211,534. Suitable amines are
predominantly C.sub.12 to C.sub.40 primary, secondary, tertiary or
quaternary amines or mixtures thereof but shorter chain amines may
be used provided the resulting nitrogen compound is oil soluble,
normally containing about 30 to 300 total carbon atoms. The
nitrogen compound preferably contains at least one straight chain
C.sub.8 to C.sub.40, preferably C.sub.14 to C.sub.24, alkyl
segment.
[0039] Suitable amines include primary, secondary, tertiary or
quaternary, but are preferably secondary. Tertiary and quaternary
amines only form amine salts. Examples of amines include
tetradecylamine, cocoamine, and hydrogenated tallow amine. Examples
of secondary amines include dioctadecyl amine and methylbehenyl
amine. Amine mixtures are also suitable such as those derived from
natural materials. A preferred amine is a secondary hydrogenated
tallow amine, the alkyl groups of which are derived from
hydrogenated tallow fat composed of approximately 4% C14, 31% C16,
and 59% C18.
[0040] Examples of suitable carboxylic acids and their anhydrides
for preparing the nitrogen compounds include ethylenediamine
tetraacetic acid, and carboxylic acids based on cyclic skeletons,
e.g., cyclohexane-1,2-dicarboxylic acid,
cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic
acid and naphthalene dicarboxylic acid, and 1,4-dicarboxylic acids
including dialkyl spirobislactones. Generally, these acids have
about 5 to 13 carbon atoms in the cyclic moiety. Preferred acids
useful in the present invention are benzene dicarboxylic acids
e.g., phthalic acid, isophthalic acid, and terephthalic acid.
Phthalic acid and its anhydride are particularly preferred. The
particularly preferred compound is the amide-amine salt formed by
reacting 1 molar portion of phthalic anhydride with 2 molar
portions of dihydrogenated tallow amine. Another preferred compound
is the diamide formed by dehydrating this amide-amine salt.
[0041] Other examples are long chain alkyl or alkylene substituted
dicarboxylic acid derivatives such as amine salts of monoamides of
substituted succinic acids, examples of which are known in the art
and described in U.S. Pat. No. 4,147,520, for example, which is
incorporated herein by reference. Suitable amines may be those
described above.
[0042] Other examples are condensates, for example, those described
in EP-A-327427. Compounds containing a cyclic ring system--carrying
at least two substituents of the general formula below on the ring
system --A--NR.sub.15R.sub.16 where A is a linear or branched chain
aliphatic hydrocarbylene group optionally interrupted by one or
more hetero atoms, and R.sub.15 and R.sub.16 are the same or
different and each is independently a hydrocarbyl group containing
9 to 40 atoms optionally interrupted by one or more hetero atoms,
the substituents being the same or different and the compound
optionally being in the form of a salt thereof. Advantageously, A
has from 1 to 20 carbon atoms and is preferably a methylene or
polymethylene group. Such compounds are described in WO
93/04148.
[0043] Hydrocarbon polymer. Examples of suitable hydrocarbon
polymers are those of the general formula CxHy where x=1-40 and
y=sufficient number of hydrogens to make all carbons tetravalent.
The hydrocarbon polymers may be made directly from
monoethylenically unsaturated monomers or indirectly by
hydrogenating polymers from polyunsaturated monomers, e.g.,
isoprene and butadiene. Examples of hydrocarbon polymers are
disclosed in WO 91/11488.
[0044] Preferred copolymers are ethylene alpha-olefin copolymers,
having a number average molecular weight of at least 30,000.
Preferably the alpha-olefin has at most 28 carbon atoms. Examples
of such olefins are propylene, n-butene, isobutene, n-octene-1,
isooctene-1, n-decene-1, and n-dodecene-1. The copolymer may also
comprise small amounts, e.g., up to 10% by weight, of other
copolymerizable monomers, for example olefins other than
alpha-olefins, and non-conjugated dienes. The preferred copolymer
is an ethylene-propylene copolymer.
[0045] The number average molecular weight of the ethylene
alphaolefin copolymer is, as indicated above, preferably at least
30,000, as measured by gel permeation chromatography (GPC) relative
to polystyrene standards, advantageously at least 60,000 and
preferably at least 80,000. Functionally no upper limit arises but
difficulties of mixing result from increased viscosity at molecular
weights above about 150,000, and preferred molecular weight ranges
are from 60,000 and 80,000 to 120,000.
[0046] Advantageously, the copolymer has a molar ethylene content
between 50 and 85 per cent. More advantageously, the ethylene
content is within the range of from 57 to 80%, and preferably it is
in the range from 58 to 73%; more preferably from 62 to 71%, and
most preferably 65 to 70%.
[0047] Preferred ethylene alpha-olefin copolymers are
ethylene-propylene copolymers with a molar ethylene content of from
62 to 71% and a number average molecular weight in the range 60,000
to 120,000; especially preferred copolymers are ethylene-propylene
copolymers with an ethylene content of from 62 to 71% and a
molecular weight from 80,000 to 100,000.
[0048] The copolymers may be prepared by any of the methods known
in the art, for example using a Ziegler type catalyst. The polymers
should be substantially amorphous, since highly crystalline
polymers are relatively insoluble in fuel oil at low
temperatures.
[0049] Other suitable hydrocarbon polymers include a low molecular
weight ethylene-alpha-olefin copolymer, advantageously with a
number average molecular weight of at most 7,500, advantageously
from 1,000 to 6,000, and preferably from 2,000 to 5,000, as
measured by vapor phase osmometry. Appropriate alpha-olefins are as
given above, or styrene, with propylene again being preferred.
Advantageously the ethylene content is from 60 to 77 molar per
cent, although for ethylene-propylene copolymers up to 86 molar per
cent by weight ethylene may be employed with advantage.
[0050] The hydrocarbon polymer may most preferably be an
oil-soluble hydrogenated block diene polymer, comprising at least
one crystallizable block, obtainable by end-to-end polymerization
of a linear diene, and at least one non-crystallizable block, the
non-crystallizable block being obtainable by 1,2-configuration
polymerization of a linear diene, by polymerization of a branched
diene, or by a mixture of such polymerizations.
[0051] Advantageously, the block copolymer before hydrogenation
comprises units derived from butadiene only, or from butadiene and
at least one comonomer of the formula
CH.sub.2.dbd.CR.sub.1--CR.sub.2.dbd.CH.sub.2 wherein R.sub.1
represents a C.sub.1 to C.sub.8 alkyl group and R.sub.2 represents
hydrogen or a C.sub.1 to C.sub.8 alkyl group. Advantageously the
total number of carbon atoms in the comonomer is 5 to 8, and the
comonomer is advantageously isoprene. Advantageously, the copolymer
contains at least 10% by weight of units derived from
butadiene.
[0052] In general, the crystallizable block or blocks will be the
hydrogenation product of the unit resulting from predominantly 1,4-
or end-to-end polymerization of butadiene, while the
non-crystallizable block or blocks will be the hydrogenation
product of the unit resulting from 1,2-polymerization of butadiene
or from 1,4-polymerization of an alkyl-substituted butadiene.
[0053] A polyoxyalkylene compound. Examples are polyoxyalkylene
esters, ethers, ester/ethers and mixtures thereof, particularly
those containing at least one, preferably at least two, C10 to C30
linear alkyl groups and a polyoxyalkylene glycol group of molecular
weight up to 5,000, preferably 200 to 5,000, the alkyl group in
said polyoxyalkylene glycol containing from 1 to 4 carbon atoms.
These materials form the subject of EP-A-0 061 895. Other such
additives are described in U.S. Pat. No. 4,491,455.
[0054] The preferred esters, ethers or ester/ethers are those of
the general formula R.sub.31--O(D)--O--R.sub.32 where R.sub.31 and
R.sub.32 may be the same or different and represent [0055] (a)
n-alkyl-- [0056] (b) n-alkyl-CO-- [0057] (c) n-alkyl-O--CO(CH2)x--
or [0058] (d) n-alkyl-O--CO(CH2)x--CO-- x being, for example, 1 to
30, the alkyl group being linear and containing from 10 to 30
carbon atoms, and D representing the polyalkylene segment of the
glycol in which the alkylene group has 1 to 4 carbon atoms, such as
a polyoxymethylene, polyoxyethylene or polyoxytrimethylene moiety
which is substantially linear; some degree of branching with lower
alkyl side chains (such as in polyoxypropylene glycol) may be
present but it is preferred that the glycol is substantially
linear. D may also contain nitrogen.
[0059] Examples of suitable glycols are substantially linear
polyethylene glycols (PEG) and polypropylene glycols (PPG) having a
molecular weight of from 100 to 5,000, preferably from 200 to
2,000. Esters are preferred and fatty acids containing from 10-30
carbon atoms are useful for reacting with the glycols to form the
ester additives, it being preferred to use a C18-C24 fatty acid,
especially behenic acid. The esters may also be prepared by
esterifying polyethoxylated fatty acids or polyethoxylated
alcohols.
[0060] Polyoxyalkylene diesters, diethers, ether/esters and
mixtures thereof are suitable as additives, diesters being
preferred for use in narrow boiling distillates, when minor amounts
of monoethers and monoesters (which are often formed in the
manufacturing process) may also be present. It is preferred that a
major amount of the dialkyl compound be present. In particular,
stearic or behenic diesters of polyethylene glycol, polypropylene
glycol or polyethylene/polypropylene glycol mixtures are
preferred.
[0061] Other examples of polyoxyalkylene compounds are those
described in Japanese Patent Publication Nos. 2-51477 and 3-34790,
and the esterified alkoxylated amines described in EP-A-117,108 and
EP-A-326,356.
[0062] It is within the scope of the invention to use two or more
additional flow improvers advantageously selected from one or more
of the different classes outlined above.
[0063] If an additional flow improver is employed, it is
advantageously employed in a proportion within the range of from
0.01% to 1%, advantageously 0.05% to 0.5%, and preferably from
0.075 to 0.25%, by weight, based on the weight of fuel.
[0064] The pour point depressant additive of the invention may also
be used in combination with one or more other co-additives such as
known in the art, for example the following: detergents,
particulate emission reducers, storage stabilizers, antioxidants,
corrosion inhibitors, dehazers, demulsifiers, antifoaming agents,
cetane improvers, cosolvents, package compatibilizers, and
lubricity additives.
[0065] Additive concentrates according to the invention
advantageously contain between 3 and 75%, preferably between 10 and
65%, of the pour point depressant additive in an oil or a solvent
miscible with oil.
[0066] The concentrate comprising the additive in admixture with a
suitable solvent are convenient as a means for incorporating the
additive into bulk oil such as distillate fuel, which incorporation
may be done by methods known in the art. The concentrates may also
contain the other additives as required and preferably contain from
3 to 75 wt %, more preferably 3 to 60 wt %, most preferably 10 to
50 wt % of the additives preferably soluble in oil. Examples of
solvent are organic solvents including hydrocarbon solvents, for
example petroleum fractions such as naphtha, kerosene, diesel and
heater oil; aromatic hydrocarbons such as aromatic fractions, e.g.
those sold under the `SOLVESSO` tradename; alcohols and/or esters;
and paraffinic hydrocarbons such as hexane and pentane and
isoparaffins. The solvent must, of course, be selected having
regard to its compatibility with the additive and with the oil.
[0067] The oil, preferably crude oil or fuel oil, composition of
the invention advantageously contains the pour point depressant
polymer of the invention in a proportion of 0.0005% to 1%,
advantageously 0.001 to 0.1%, and preferably 0.01 to 0.06% by
weight, based on the weight of oil.
[0068] In one embodiment, the oil-containing composition of the
invention comprises crude oil, i.e. oil obtained directly from
drilling and before refining.
[0069] The oil may be a lubricating oil, which may be an animal,
vegetable or mineral oil, such, for example, as petroleum oil
fractions ranging from naphthas or spindle oil to SAE 30, 40 or 50
lubricating oil grades, castor oil, fish oils, oxidized mineral
oil, or biodiesels. Such oils may contain additives depending on
its intended use; examples are viscosity index improvers such as
ethylene-propylene copolymers, succinic acid based dispersants,
metal containing dispersant additives and zinc
dialkyldithiophosphate antiwear additives. The pour point
depressant of this invention may be suitable for use in lubricating
oils as a flow improver, pour point depressant or dewaxing aid.
[0070] In another embodiment the oil is a fuel oil, e.g., a
petroleum-based fuel oil, especially a middle distillate fuel oil.
Such distillate fuel oils generally boil within the range of from
110.degree. C. to 500.degree. C., e.g. 150.degree. C. to
400.degree. C. The fuel oil may comprise atmospheric distillate or
vacuum distillate, cracked gas oil, or a blend in any proportion of
straight run and thermally and/or catalytically cracked
distillates. The most common petroleum distillate fuels are
kerosene, jet fuels, diesel fuels, heating oils and heavy fuel
oils. The heating oil may be a straight atmospheric distillate, or
it may contain minor amounts, e.g. up to 35wt %, of vacuum gas oil
or cracked gas oil or of both. The above-mentioned low temperature
flow problem is most usually encountered with diesel fuels and with
heating oils. The invention is also applicable to vegetable-based
fuel oils, for example rapeseed oil, used alone or in admixture
with a petroleum distillate oil.
[0071] The invention will now be illustrated by the following
nonlimiting example.
EXAMPLE 1
[0072] Aromatic 150 (about 25% by weight of the product), C-20-24
Alpha Olefin (1.0 mole), and Maleic Anhydride (1.15 moles) are
stirred in a flask equipped with an inert nitrogen subsurface
sparge to eliminate air from the product and overhead and set for
total reflux. The mixture is heated to 130.degree. C. and then
tert-butyl peroxybenzoate (0.02 moles) is slowly added continuously
over a two to three hour period while maintaining the temperature
at 130.degree. C. and then allowed to react in for an additional
hour. The flask is then set to collect distillate and the premelted
tallowamine (1.15 moles) is then added to the mixture allowing the
exotherm along with external heating to hold the product at
130-150.degree. C. for 2 hours. Water will be collected as the
imide is formed during this step. The resulting product was tested
as a potential wax crystalline modifier against our current product
(PC-105) used for this application. The pour point test results
(attached) show that the experimental product (labeled RLC-2) was
better at 200 ppm treating levels than our current PC-105 (labeled
RLC-1) at 600 ppm treating levels. When the experimental product
was used at the 600 ppm treating levels, it was even more effective
(i.e. reduced the pour point of the crude all the way to 20.degree.
F.) at reducing the pour point of the crude that would normally not
flow at 70.degree. F. without treatment.
[0073] The pour point test results are compiled in Table 1, below.
TABLE-US-00001 TABLE 1 Sample Analysis (D5853-95, Procedure 9.1.5)
Test Description: Akzonobel Pour Point Depressant Evaluation Sample
ID GoM Crude GoM Crude GoM Crude GoM Crude GoM Crude Sample
Description: No Additive 200 ppm RLC-1 600 ppm RLC-1 200 ppm RLC-2
600 ppm RLC-2 Start Time 9:17 9:17 9:17 9:17 9:17 Start Temp. 120
F. 120 F. 120 F. 120 F. 120 F. Bath 2 (70.degree. F.) Time: 13:00
115.degree. F. Flowing Flowing Flowing Flowing Flowing 110.degree.
F. 105.degree. F. 100.degree. F. 95.degree. F. 90.degree. F.
85.degree. F. Bath 3 (32.degree. F.) Time: 13:50 80.degree. F
75.degree. F. 70.degree. F. No Flow No Flow 65.degree. F.
.quadrature. .quadrature. 60.degree. F. .quadrature. .quadrature.
No Flow 55.degree. F. .quadrature. .quadrature. 50.degree. F.
.quadrature. .quadrature. .quadrature. Bath 4 (0.degree. F.) Time:
.quadrature. .quadrature. .quadrature. .quadrature. 14:44
45.degree. F. .quadrature. .quadrature. .quadrature. 40.degree. F.
.quadrature. .quadrature. .quadrature. No Flow 35.degree. F.
.quadrature. .quadrature. .quadrature. .quadrature. 30.degree. F.
.quadrature. .quadrature. .quadrature. .quadrature. 25.degree. F.
.quadrature. .quadrature. .quadrature. .quadrature. 20.degree. F.
.quadrature. .quadrature. .quadrature. .quadrature. 15.degree. F.
.quadrature. .quadrature. .quadrature. .quadrature. No Flow Bath 5
(-27.degree. F.) Time: 10.degree. F. .quadrature. .quadrature.
.quadrature. .quadrature. .quadrature. 5.degree. F. .quadrature.
.quadrature. .quadrature. .quadrature. .quadrature.
* * * * *