U.S. patent application number 12/700948 was filed with the patent office on 2011-08-11 for composition having improved filterability.
This patent application is currently assigned to EVONIK ROHMAX ADDITIVES GMBH. Invention is credited to Robert Cybert, Brian HESS, Rene Koschabek, Frank-Olaf Maehling, Marie Malitsky, Ronny Sondjaja.
Application Number | 20110192076 12/700948 |
Document ID | / |
Family ID | 43501020 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110192076 |
Kind Code |
A1 |
HESS; Brian ; et
al. |
August 11, 2011 |
COMPOSITION HAVING IMPROVED FILTERABILITY
Abstract
The present invention describes a fuel oil composition
comprising at least one biodiesel oil and at least one additive for
improving the filterability. In addition thereto, the present
invention discloses a method for improving the filterability of a
fuel oil comprising a biodiesel and a use of a
polyalkyl(meth)acrylate polymer to improve the filterability of a
fuel oil comprising a biodiesel
Inventors: |
HESS; Brian; (Willow Grove,
PA) ; Cybert; Robert; (Roosevelt, NJ) ;
Malitsky; Marie; (Plymouth Meeting, PA) ; Maehling;
Frank-Olaf; (Mannheim, DE) ; Koschabek; Rene;
(Weinheim, DE) ; Sondjaja; Ronny; (Bandung,
ID) |
Assignee: |
EVONIK ROHMAX ADDITIVES
GMBH
Darmstadt
DE
|
Family ID: |
43501020 |
Appl. No.: |
12/700948 |
Filed: |
February 5, 2010 |
Current U.S.
Class: |
44/388 |
Current CPC
Class: |
C10L 10/16 20130101;
Y02E 50/10 20130101; C10L 10/14 20130101; C10L 1/1963 20130101 |
Class at
Publication: |
44/388 |
International
Class: |
C10L 1/196 20060101
C10L001/196 |
Claims
1. A fuel oil composition comprising a biodiesel oil characterized
in that the fuel composition comprises at least one additive for
improving the filterability.
2. The fuel oil composition according to claim 1 wherein the
additive for improving the filterability comprises at least one
polymer comprising ester groups having a number average molecular
weight Mn of from 750 to 100000 g/mol and a polydispersity Mw/Mn of
from 1 to 8.
3. The fuel oil composition according to claim 2 wherein said
polymer comprising ester groups comprises a weight average
molecular weight Mw in the range of 1000 to 60000 g/mol.
4. The fuel oil composition according to claim 2 wherein said
polymer comprising ester groups is a polyalkyl(meth)acrylate
polymer having a number average molecular weight Mn of from 750 to
100000 g/mol and a polydispersity Mw/Mn of from 1 to 8.
5. The fuel oil composition according to claim 3 wherein said
polymer comprising ester groups is a polyalkyl(meth)acrylate
polymer comprises a weight average molecular weight Mw in the range
of 1000 to 60000 g/mol.
6. The fuel oil composition according to claim 4 wherein said
polyalkyl(meth)acrylate polymer comprises at least 40% by weight of
repeating units being derived from alkyl (meth)acrylates having 7
to 40 carbon atoms in the alkyl residue.
7. The fuel oil composition according to claim 4 wherein
polydispersity Mw/Mn of said polyalkyl(meth)acrylate polymer is in
the range of from 1.2 to 5.
8. The fuel oil composition according to claim 4 wherein said
polyalkyl(meth)acrylate polymer comprises 5 to 80% by weight of
repeating units being derived from alkyl (meth)acrylates having 16
to 40 carbon atoms in the alkyl residue.
9. The fuel oil composition according to claim 8 wherein said
polyalkyl(meth)acrylate polymer comprises a weight ratio of
repeating units being derived from alkyl (meth)acrylates having 16
to 40 carbon atoms in the alkyl residue to repeating units being
derived from alkyl (meth)acrylates having 7 to 15 carbon atoms in
the alkyl residue being in the range from 3:1 to 1:1.
10. The fuel oil composition according to claim 1 wherein said
additive for improving the filterability comprises at least two
polyalkyl(meth)acrylate polymers.
11. The fuel oil composition according to claim 10 wherein one of
the polyalkyl(meth)acrylate polymers comprises repeating units
being derived from alkyl (meth)acrylates having 16 to 40 carbon
atoms in the alkyl residue.
12. The fuel oil composition according to claim 11 wherein one of
the polyalkyl(meth)acrylate polymers comprises repeating units
which are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols.
13. The fuel oil composition according to claim 12 wherein the
polyalkyl(meth)acrylate polymers comprises repeating units which
are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols have a lower molecular weight
than the other polyalkyl(meth)acrylate polymer.
14. The fuel oil composition according to claim 12 wherein the
weight ratio of said polyalkyl(meth)acrylate polymers comprising
repeating units being derived from alkyl (meth)acrylates having 16
to 40 carbon atoms in the alkyl residue to said other
polyalkyl(meth)acrylate polymer is in the range from 10:1 to
1:10.
15. The fuel oil composition according to claim 1 wherein said
composition comprises at least 70% by weight fuel oil.
16. The fuel oil composition according to claim 1 wherein said fuel
oil comprises a mineral oil.
17. The fuel oil composition according to claim 1 wherein said
biodiesel comprises fatty acid enters which are derived from
monohydric alcohols having 1 to 4 carbon atoms.
18. The composition according to claim 17 wherein said biodiesel
comprises at least 10% by weight of fatty acid esters which are
derived from methanol and/or ethanol and saturated fatty acids.
19. The fuel oil composition according to claim 1 wherein said
biodiesel comprises at least 5 ppm steryl glycosides.
20. The fuel oil composition according to claim 19 wherein said
biodiesel comprises at least 20 ppm steryl glycosides.
21. The fuel oil composition according to claim 1 wherein said
biodiesel comprises a Ranzimat value of at least 6 hours.
22. The fuel oil composition according to claim 1 wherein said
biodiesel comprises a CSFT value of 300 ml after 500 seconds
without any additive for improving the filterability.
23. The fuel oil composition according to claim 22 wherein said
biodiesel comprises a CSFT value of at most 250 ml after 720
seconds without any additive for improving the filterability.
24. The fuel oil composition according to claim 1 wherein said
biodiesel comprises a CSFT value of at most 300 ml after 350
seconds with an effective amount of said additive for improving the
filterability.
25. The fuel oil composition according to claim 1 wherein said
biodiesel comprises 0.15 to 1.0% by weight additive for improving
the filterability.
26. A method for improving the filterability of a fuel oil
comprising a biodiesel wherein an additive for improving the
filterability is added to said fuel oil composition.
27. The method according to claim 26 wherein a
polyalkyl(meth)acrylate polymer having a number average molecular
weight Mn of from 750 to 100000 g/mol and a polydispersity Mw/Mn of
from 1 to 8 is added as an additive for improving the filterability
to the fuel oil compositions.
28. A use of a polyalkyl(meth)acrylate polymer having a number
average molecular weight Mn of from 750 to 100000 g/mol and a
polydispersity Mw/Mn of from 1 to 8 to improve the filterability of
a fuel oil comprising a biodiesel.
Description
[0001] The present application relates to a composition having
improved filterability. Furthermore the present invention describes
a use of polymers for improving the filterability of fuel oils.
[0002] Fuels are nowadays mostly obtained from fossil sources.
However, these resources are limited, so that replacements are
being sought. Therefore, interest is rising in renewable raw
materials which can be used to produce fuels. A very interesting
replacement is in particular biodiesel fuel.
[0003] The term biodiesel is in many cases understood to mean a
mixture of fatty acid esters, usually fatty acid methyl esters
(FAMEs), with chain lengths of the fatty acid fraction of 12 to 24
carbon atoms with 0 to 3 double bonds. The higher the carbon number
and the fewer double bonds are present, the higher is the melting
point of the FAME. Typical raw materials are vegetable oils (i.e.
glycerides) such as rapeseed oils (canola oils), sunflower oils,
soya oils, palm oils, coconut oils and, in isolated cases, even
used vegetable oils. Another typical source for Biodiesel is animal
fat. The raw materials are converged to the corresponding FAMEs by
transesterification, usually with methanol under basic
catalysis.
[0004] Currently rapeseed oil methyl ester (RME) is the preferred
stock for biodiesel production in Europe as rapeseed produces more
oil per unit of land area compared to other oil sources. However
with the high price level of RME, mixtures of RME with other
feedstock, such as soybean (SME) or palm methyl ester (PME), have
been exploited as well. In addition to the utilization of 100%
biodiesel, mixtures of fossil diesel, i.e. the middle distillate of
crude oil distillation, and biodiesel are also of interest owing to
the improved low-temperature properties and better combustion
characteristics.
[0005] The use of biodiesel in cold climates may require special
considerations due to the tendency of precipitates to form in the
biodiesel at temperatures of 0.degree. C. and below. These
precipitates impair the flow characteristics of biodiesel. Based on
failures of truck engines during a bitter 2005 cold spell in
Minnesota, a new requirement In terms of an ASTM specification has
been developed, the so called Cold Soak Filter Test (CSFT). At
present the specifications ASTM D 6751 and ASTM D 7501 are in use,
respectively.
[0006] Another temperature independent phenomenon of precipitation
is sometimes observed in biodiesel after storage.
[0007] There are some hints that steryl glucosides (SG) could be
the source for these precipitates. Indeed methods have been
developed to reduce the levels of these impurities by way of some
sophisticated filtration methods as disclosed e.g. by Lee et al. in
"The Role of Sterol Glucosides on Filter Plugging", Biodiesel
Magazine, April 2007. Furthermore, some oxidation products may
cause some problems in filter blocking. The particulate is usually
highly dispersed and the samples pass the conventional filter
tests. However, the cold soak filter test according to ASTM D 7501
stimulates an aggregation of these particulates. For solving the
problems being related to these particulates, sophisticated
purifying methods have been developed. However, the purifying
treatments being used to achieve a low steryl glycoside content are
very expensive and complex.
[0008] Polyalkyl (meth)acrylates, PA(M)As, as pour point improvers
for mineral oils, either without M(M)A (e.g. U.S. Pat. No.
3,869,396 to Shell Oil Company) or with M(M)A (e.g. U.S. Pat. No.
5,312,884 to Rohm & Haas Company), or else as pour point
improvers for ester-based lubricants (U.S. Pat. No. 5,696,066 to
Rohm & Haas Company) have been established and described for
quite a long time. Use of these polymers in fuel compositions which
comprise at least one biodiesel fuel is, however, not
described.
[0009] In addition, the publication WO 01/40334 (RohMax Additives
GmbH) describes polyalkyl (meth)acrylates which can be used in
biodiesel fuels. This publication provides a particular preparation
which imparts exceptional properties to these polymers. However,
there is a lack therein of examples relating to biodiesel
fuels.
[0010] Flow improvers based on oil-soluble polymers for mixtures of
fossil diesel and biodiesel are also known (WO 94/10267, Exxon
Chemical Patents Inc.). However, the examples describe only
ethylene-vinyl acetate copolymers (EVAs) and copolymers which have
C.sub.12/C.sub.14-alkyl fumarate and vinyl acetate units.
[0011] In addition, a series of optimized EVA copolymers for
diesel/biodiesel mixtures have also become known (EP 1 541 662 to
664; WO 2008/113735 and DE 103 57 877). For instance, EP 1 541 663
describes mixtures comprising 75% by volume of diesel fuel of
mineral origin and 25% by volume of biodiesel, which comprise 150
ppm of poly(dodecyl methacrylate) and 100 to 200 ppm of
ethylene-vinyl acetate copolymer (EVA).
[0012] In addition, additives for fuel mixtures which comprise
mineral diesel and biodiesel are described in WO 2007/113035. In
addition, the low-temperature properties achievable in
diesel/biodiesel mixtures through addition of additives are not
necessarily applicable to pure biodiesel fuels, since their boiling
behaviour, their viscosity and hence their chemical composition,
i.e. hydrocarbon chain length distribution is different.
[0013] The known polymers show an acceptable efficiency as cold
flow improvers in fossil diesel fuel and in purified biodiesel fuel
as mentioned above. However, no hints are available that some of
these polymers may be used to improve the filterability of low
purified biodiesel fuel oils. Indeed conventional biodiesel is
thoroughly purified to a level such that no problems occur with the
particulates being the reason for a low filterability.
[0014] Indeed in prior art documents no problems with filterability
have been described and, hence, no biodiesel fuel with a low
filterability is described having an effective amount of the
polymeric additives as described above.
[0015] In view of the prior art, it is thus an object of the
present invention to provide a fuel oil comprising biodiesel having
a high filterability without performing a sophisticated purifying
process of the biodiesel fuel. The filterability should be
maintained over a long storage time and after a cold soak
period.
[0016] At the same time, the fuel should more particularly have
very good low-temperature properties. It was a further object of
the present invention to provide a fuel which possesses a high
stability to oxidation. In addition, the fuel should have a maximum
cetane number. At the same time, the novel fuels should be
producible simply and inexpensively.
[0017] Preferred fuel compositions should give a property profile
which corresponds essentially to that of mineral diesel fuel
comprise a maximum proportion of renewable raw materials.
[0018] It was a further object of the present invention to provide
additives which are capable of improving the filterability of
biodiesel and biodiesel blends. It was a further object of the
present invention to provide fuels which, when stored below the
cloud point, exhibit only minor precipitation. At the same time,
this formation of precipitate should be delayed for as long as
possible.
[0019] These objects and further objects which are not stated
explicitly but which are immediately derivable or discernible from
the connections discussed wherein by way of introduction are
achieved by a fuel composition having all features of claim 1.
Appropriate modifications of the inventive fuel composition are
protected in the dependent claims referring back to Claim 1. As to
the methods for improving filterability, the Claim 26 provides a
solution to the underlying problem. With regard to the use of
polymers comprising ester groups as filter ability improvers, Claim
28 constitutes a solution to the problem.
[0020] The present invention accordingly provides a fuel oil
composition comprising a biodiesel oil, characterized in that the
fuel composition comprises at least one additive for improving the
filterability.
[0021] This makes it possible, in an unforeseeable manner, to
provide a fuel composition which comprises a biodiesel fuel and
which includes an excellent profile of properties. For instance,
the fuel oil has a high filterability without performing a
sophisticated purifying process of the biodiesel fuel used. The
filterability is maintained over a long storage time and after a
cold soak period.
[0022] In addition thereto, the present fuel compositions
especially have a surprisingly low cloud point, very good
low-temperature storability and excellent flow properties at low
temperatures.
[0023] At the same time, the fuel oil compositions allow a series
of further advantages to be achieved. These include:
[0024] The compositions of the present invention snow exceptional
cold flow properties. Furthermore, these improvements are achieved
by applying low or high amounts of the additives to the fuel oil.
The compositions of the present invention can be prepared in a
particularly easy and simple manner. It is possible to use
customary industrial scale plants.
[0025] The fuel composition of the present invention comprises at
least one biodiesel fuel component. Biodiesel fuel is a substance,
especially an oil, which is obtained from vegetable or animal
material or both, or a derivative thereof, which can in principle
be used as a replacement for mineral diesel fuel.
[0026] In a preferred embodiment, the biodiesel fuel, which is
frequently also referred to as "biodiesel" or "biofuel", comprises
fatty acid alkyl esters of fatty acids having preferably 6 to 30
and more preferably 12 to 24 carbon atoms, and monohydric alcohols
having 1 to 4 carbon atoms. In many cases, some of the fatty acids
may contain one, two or three double bonds. The monohydric alcohols
include especially methanol, ethanol, propanol and butanol,
preference being given to methanol.
[0027] Examples of oils which derive from animal or vegetable
material and which can be used in accordance with the invention are
palm oil, rapeseed oil, coriander oil, soya oil, cottonseed oil,
sunflower oil, castor oil, olive oil, peanut oil, corn oil, almond
oil, palm kernel oil, coconut oil, mustardseed oil, oils derived
from animal tallow, especially bovine tallow, bone oil, fish oils
and used cooking oils. Further examples include oils which derive
from cereals, wheat, jute, sesame, rice husks, jatropha, arachis
oil and linseed oil. Surprising advantages can be achieved
especially in the case of use of palm oil, soya oil, jatropha oil
or animal tallow, especially beef fat, chicken fat or pork fat, as
a reactant for preparing biodiesel. The fatty acid alkyl esters for
use with preference can be obtained from these oils by methods
known in the prior art.
[0028] According to a special embodiment, preference is given in
accordance with the invention to oils with a high
C16:0/C18:0-glyceride content, such as palm oils and oils derived
from animal tallow, and derivatives thereof, especially the palm
oil alkyl esters which are derived from monohydric alcohols. Palm
oil (also: palm fat) is obtained from the flesh of the palm fruits.
The fruits are sterilized and pressed. Owing to their high carotene
content, fruits and oil have an orange-red colour which is removed
in the refining step. These oils may contain up to 80%
C18:0-glyceride.
[0029] According to another embodiment of the present invention,
oils with a high C18:1, C18:2 and C18:3-glyceride and derivatives
thereof, especially alkyl esters which are derived from monohydric
alcohols content an; preferred. These oils include cottonseed oil,
wheat germ oil, soya oil, olive oil, corn oil, sunflower oil,
sunflower oil, hemp oil, canola/rapeseed oil. These oils may
preferably contain at least 60%, especially at least 75% by weight
and more preferably at least 90% by weight C18:1, C18:2 and/or
C18:3-glyceride.
[0030] Particularly suitable biodiesel fuels are lower alkyl esters
of fatty acids. Examples here include commercial mixtures of the
ethyl, propyl, butyl and especially methyl esters of fatty acids
having 6 to 30, preferably 12 to 24 and more preferably 14 to 22
carbon atoms, for example of caprylic acid, capric acid, lauric
acid, myristic acid, palmitic acid, margaric acid, arachic acid,
behenic acid, lignoceric acid, cerotic acid, palmitoleic acid,
stearic acid, oleic acid, elaidic acid, petroselic acid, ricinoleic
acid, elaeostearic acid, linoleic acid, linolenic acid, eicosanoic
acid, gadoleinic acid, docosanoic acid or erucasic acid.
[0031] In a particular aspect of the present invention, a biodiesel
fuel which comprises preferably a; least 30% by weight, more
preferably at least 35% by weight and most preferably at least 40%
by weight of saturated fatty acid esters which have at least 16
carbon atoms in the fatty acid part is preferably used. This
includes especially the esters of palmitic acid and stearic acid.
Advantages which were unforeseeable for the person skilled in the
art can especially be achieved with fuels which comprise at least
6% by weight, more preferably at least 10% by weight and most
preferably at least 40% by weight of palmitic acid methyl ester
and/or stearic acid methyl ester.
[0032] According to another embodiment of the present invention, a
biodiesel fuel which comprises preferably at least 60% by weight,
more preferably at least 75% by weight and most preferably at least
90% by weight of unsaturated fatty acid esters which have at least
18 carbon atoms in the fatty acid part is preferably used. This
includes especially the esters of oleic acid, linoleic and/or
linolenic acid. Advantages which were unforeseeable for the person
skilled in the art can especially be achieved with fuels which
comprise at least 40% by weight, more preferably at least 60% by
weight and most preferably at least 80% by weight of oleic acid
methyl ester, linoleic methyl ester and/or linolenic acid methyl
ester.
[0033] For reasons of cost, these fatty acid esters are typically
used as a mixture. Biodiesel fuels usable in accordance with the
invention preferably have an iodine number of at most 150,
especially at most 125, more preferably at most 70 and most
preferably at most 60. The iodine number is a measure known per se
for the content in a fat or oil of unsaturated compounds, which can
be determined to DIN 53241-1. As a result, the fuel compositions of
the present invention form a particularly low level of deposits in
the diesel engines. In addition, these fuel compositions exhibit
particularly high cetane numbers.
[0034] In general, the fuel compositions of the present invention
may comprise at least 2% by weight, in particular at least 5% by
weight, particularly at least 10% by weight, more particularly at
least 20% by weight, especially at least 50% by weight, preferably
at least 80% by weight and more preferably at least 95% by weight
of biodiesel fuel.
[0035] As mentioned above, the biodiesel of the present invention
may comprise impurities and, hence, a low purified biodiesel can be
used. Preferably, the biodiesel may comprise at least 5 ppm,
especially at least 10 ppm, particularly at least 20 ppm,
preferably at least 30 ppm and more preferably at least 50 ppm
steryl glycosides. Steryl glycosides are well known in the art. The
steryl glycosides present in biodiesel comprise a sterol group
linked to a carbohydrate at the hydroxyl moiety of the sterol. The
steryl glycosides may also contain a fatty acid esterified to a
hydroxyl group of the carbohydrate moiety; these compounds may be
described as acylated steryl glycosides. The steryl glycosides
include sterol glucosides, steryl glucosides, or sterol
glycosides.
[0036] Acylated steryl glycosides are naturally occurring compounds
found in plants. The acylated steryl glycosides comprise a sterol
group bound to a carbohydrate having a fatty acid acylated to the
primary hydroxyl group of the carbohydrate moiety of a steryl
glycoside. One of the acylated steryl glycosides present in soybean
extracts is the 6'-linoleoyl-beta-D-glucoside of beta sitosterol
present at about 47%. In plants, other fatty acids or monobasic
carboxylic acids, such as palmitic acid, oleic acid, stearic acid,
linoleic acid, and linolenic acid may also be acylated to the
carbohydrate moiety through an ester bond. The acylated steryl
glycosides are two to ten times more abundant in plants than the
(non-acylated) steryl glycosides. Steryl glycosides, also known as
sterolins, are present as monoglycosides in the oil from which
biodiesel is synthesized, although a few diglycosides also exist. A
common sugar in steryl glycosides is D-glucose, which is joined to
the sterol via the 3-beta-hydroxy group by means of an equatorial
or beta-glucoside bond. Other monosaccharides that may be found in
steryl glycosides include mannose, galactose, arabinose and
xylose.
[0037] For further details see, e.g. "The Role of Sterol Glucosides
on Filter Plugging", Biodiesel Magazine, April 2007 as mentioned
above.
[0038] The presence of steryl glycosides in biodiesel can be
detected by chromatography methods, e.g. high pressure liquid
chromatography (HPLC).
[0039] According to a further embodiment of the present invention,
the biodiesel useful for the present invention may comprise a
Ranzimat value of at least 6 hours, more preferably at least 8
hours. The Ranzimat value can be determined according to DIN EN
14112.
[0040] Without any additive for improving the filterability, the
biodiesel may preferably comprises a CSFT value of 300 ml after 500
seconds, more preferably a CSFT value of at most 250 ml after 720
seconds. The CSFT value can be determined according to the ASTM D
7501 method and the data mentioned above and below consider the
volume achieved after the maximum time of about 720 s and the time
needed to filter the 300 ml sample, respectively. In order to
determine the CSFT value, a sample of the oil is stored at a low
temperature of about 4.4.degree. C. (40.degree. F.) for about 16
hours. Then the sample is allowed to warm to room temperature (20
to 22.degree. C.) prior to vacuum filtering the sample through a
single 0.7 .mu.m glass fiber filter. The vacuum pressure should be
in the range of 71.1 to 84.7 kPa. For more details see the standard
ASTM D 7501 and ASTM D 6217, respectively.
[0041] The fuel composition of the present invention further
comprises at least one additive for improving the filterability.
The fuel composition of the present invention can preferably
comprise 0.05 to 5% by weight, preferably 0.08 to 3% by weight and
more preferably 0.10 to 1.0% by weight of at least one additive for
improving the filterability.
[0042] In particular, the additive for improving the filterability
may comprise at least one polymer comprising ester groups having a
number average molecular weight Mn of from 750 to 100000 g/mol and
a polydispersity Mw/Mn of from 1 to 8. More preferably, the polymer
comprising ester groups comprises a weight average molecular weight
Mw in the range of 1000 to 60000 g/mol. The number average
molecular weight Mn and the weight average molecular weight Mw can
be determined via GPC using a methyl methacrylate polymer as
standard.
[0043] Polymers comprising ester groups are understood in the
present context to mean polymers which are obtainable by
polymerizing monomer compositions which comprise ethylenically
unsaturated compounds having it least one ester group, which are
referred to hereinafter as ester monomers. Accordingly, these
polymers contain ester groups as part of the side chain.
[0044] According to a special aspect of the present invention,
polymers based on ethyl vinyl acetate can be used as an additive
for improving the filterability. Preferred polymers based on ethyl
vinyl acetate are described in EP 0 739 971 B1, EP 0 721 492 B2 and
EP 0 741 181 B1. The documents EP 0 739 971 B1 filed with the
European Patent Office Jun. 29, 1993 under the Application number
96202136.6; EP 0 721 492 B2 filed with the European Patent Office
Jul. 22, 1994 under the Application number 94924280.4 and EP 0 741
181 B1 filed with the European Patent Office Jun. 29, 1993 under
the Application number 96202137.4 are enclosed herein by
references.
[0045] Preferably a mixture of the different EVA based polymers can
be used in order to improve the filterability of the fuel oil
comprising at least one biodiesel oil. The first EVA based polymer
may comprise ethylene, vinyl acetate and a alkyl ester of a
(meth)acrylate, a fumarate and/or a maleate. The alkyl ester
preferably contains 6 to 20, more preferably 7 to 12 carbon atoms
in the alkyl residue. As to the fumarates and/or a maleates, the
diesters are preferred. The first EVA polymer preferably has an
ethylene content in the range of 50 to 90 mol % and a vinyl acetate
content in the range of 10 to 40 mol %. The amount of alkyl ester
being derived from a (meth)acrylate, a fumarate and/or a maleate is
preferably in the range of 1 to 20 mol %, more preferably in the
range of 2 to 10 mol %. The weight average molecular weight Mw of
the first EVA polymer can preferably be situated in the range of
10000 to 50000 g/mol. The polydispersity Mw/Mn of the first EVA
polymer is preferably in the range of 1.1 to 5, more preferably 1.5
to 3. The second EVA polymer preferably has an ethylene content in
the range of 60 to 95 mol % and a vinyl acetate content in the
range of 5 to 40 mol %. The weight average molecular weight Mw of
the second EVA polymer can preferably be situated in the range of
1000 to 10000 g/mol. The polydispersity Mw/Mn of the second EVA
polymer is preferably in the range of 1.1 to 5, mere preferably 2.0
to 4.
[0046] According to a preferred embodiment of the present
invention, the additive for improving the filterability may include
polyalkyl (meth)acrylates (PAMAs), polyalkyl fumarates and/or
polyalkyl maleates.
[0047] Ester monomers for the manufacture of polyalkyl
(meth)acrylates (PAMAs), polyalkyl fumarates and/or polyalkyl
maleates are known per se. They include especially (meth)acrylates,
maleates and fumarates, which may have different alcohol parts. The
expression "(meth)acrylates" includes methacrylates and acrylates,
and mixtures of the two. These monomers are widely known. In this
context, the alkyl part may be linear, cyclic or branched. The
alkyl part may also have known substituents.
[0048] The term "repeating unit" is widely known in the technical
field. The present polymers comprising ester groups can preferably
be obtained by means of free-radical polymerization of monomers,
the controlled radical process techniques of ATRP, RAFT and NMP,
which will be explained later, being counted among the free-radical
processes in the context of the invention, without any intention
that this should impose a restriction. In these processes, double
bonds are opened up to form covalent bonds. Accordingly, the repeat
unit is obtained from the monomers used.
[0049] The polymers comprising ester groups preferably contain
repeating units derived from ester monomers having 7 to 40 carbon
atoms in the alcohol part. Preferably, the polymer comprises at
least 40% by weight, especially at least 60%; by weight and more
preferably at least 80% by weight of repeating units derived from
ester monomers having 7 to 40, preferably 7 to 30 carbon atoms in
the alcohol part.
[0050] According to a preferred embodiment the polymer may comprise
repeating units derived from ester monomers having 16 to 40,
preferably 16 to 30 carbon atoms in the alcohol part, and repeating
units derived from ester monomers having 7 to 15 carbon atoms in
the alcohol part.
[0051] The polymer comprising ester groups may contain 5 to 100% by
weight, especially 20 to 98% by weight and more preferably 30 to
60% by weight of repeat units derived from ester monomers having 7
to 15 carbon atoms in the alcohol part.
[0052] In a particular aspect, the polymer comprising ester groups
may contain 0 to 90% by weight, preferably 5 to 80% by weight and
more preferably 40 to 70% by weight of repeat units derived from
ester monomers having 16 to 40, preferably 16 to 30 carbon atoms in
the alcohol part.
[0053] In addition, the polymer comprising ester groups may contain
0.1 to 30% by weight, preferably 0.5 to 20% by weight, of repeat
units derived from ester monomers having 1 to 6 carbon atoms in the
alcohol part.
[0054] The polymer comprising ester groups comprises preferably at
least 40% by weight, more preferably at least 60% by weight,
especially preferably at least 80% by weight and very particularly
at least 95% by weight of repeat units derived from ester
monomers.
[0055] Mixtures from which the inventive polymers comprising ester
groups are obtainable may contain 0 to 40% by weight, especially
0.1 to 30% by weight and more preferably 0.5 to 20% by weight of
one or more ethylenically unsaturated ester compounds of the
formula (I)
##STR00001##
in which R is hydrogen or methyl, R.sup.1 is a linear or branched
alkyl radical having 1 to 6 carbon atoms, R.sup.2 and R.sup.3 are
each independently hydrogen or a group of the formula --COOR' in
which R' is hydrogen or an alkyl group having 1 to 6 carbon
atoms.
[0056] Examples of component (I) include
(meth)acrylates, fumarates and maleates which derive from saturated
alcohols, such as methyl (meth)acrylate, ethyl (meth)acrylate,
n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl
(meth)acrylate, tert-butyl (meth)acrylate and pentyl
(meth)acrylate, hexyl (meth)acrylate; cycloalkyl (meth)acrylates,
such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate.
[0057] The compositions to be polymerized preferably contain 0 to
100% by weight, particularly 5 to 98% by weight, especially 20 to
90% by weight and more preferably 30 to 60% by weight of one or
more ethylenically unsaturated ester compounds of the formula
(II)
##STR00002##
in which R is hydrogen or methyl, R.sup.4 is a linear or branched
alkyl radical having 7 to 15 carbon atoms, R.sup.5 and R.sup.6 are
each independently hydrogen or a group of the formula --COOR'' in
which R'' is hydrogen or an alkyl group having 7 to 15 carbon
atoms.
[0058] Examples of component (II) include:
(meth)acrylates, fumarates and maleates which derive from saturated
alcohols, such as 2-ethylhexyl (meth)acrylate, heptyl
(meth)acrylate, 2-tert-butylheptyl (meth)acrylate, octyl
(meth)acrylate, 3-isopropylheptyl (meth)acrylate, nonyl
(meth)acrylate, decyl (meth)acrylate, 2-Propylheptyl(meth)acrylate,
undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl
(meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl
(meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl
(meth)acrylate, pentadecyl (meth)acrylate; (meth)acrylates which
derive from unsaturated alcohols, for example oleyl (meth)acrylate;
cycloalkyl (meth)acrylates such as 3-vinylcyclohexyl
(meth)acrylate, bornyl (meth)acrylate; and the corresponding
fumarates and maleates.
[0059] In addition, preferred monomer compositions comprise 0 to
100% by weight, particularly 0.1 to 90% by weight, preferably 5 to
80% by weight and more preferably 40 to 70% by weight of one or
more ethylenically unsaturated ester compounds of the formula
(III)
##STR00003##
in which R is hydrogen or methyl, R.sup.7 is a linear or branched
alkyl radical having 16 to 40 and preferably 16 to 30 carbon atoms,
R.sup.8 and R.sup.9 are each independently hydrogen or a group of
the formula --COOR''' in which R''' is hydrogen or an alkyl group
having 16 to 40 and preferably 16 to 30 carbon atoms.
[0060] Examples of component (III) include (meth)acrylates which
derive from saturated alcohols, such as hexadecyl (meth)acrylate,
2-methylhexadecyl (meth)acrylate, heptadecyl (meth)acrylate,
5-isopropylheptadecyl (meth)acrylate, 4-tert-butyloctadecyl
(meth)acrylate, 5-ethyloctadecyl (meth)acrylate,
3-isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate,
ionadecyl (meth)acrylate, eicosyl (meth)acrylate, cetyleicosyl
(meth)acrylate, stearyleicosyl (meth) acrylate, docosyl
(meth)acrylate and/or eicosyltertratriacontyl (meth)acrylate;
cycloalkyl (meth)acrylates such as
2,4,5-tri-t-butyl-3-vinylcyclohexyl (meth)acrylate,
2,3,4,5-tetra-t-butylcyclohexyl (meth)acrylate, and the
corresponding fumarates and maleates.
[0061] The ester compounds with a long-chain alcohol part,
especially components (II) and (III), can be obtained, for example,
by reacting (meth)acrylates, fumarates, maleates and/or the
corresponding acids with long-chain fatty alcohols, which generally
gives rise to a mixture of esters, for example (meth)acrylates with
different long-chain hydrocarbons in the alcohol parts. These fatty
alcohols include Oxo Alcohol.RTM. 7911, Oxo Alcohol.RTM. 7900, Oxo
Alcohol.RTM. 1100; Alfol.RTM. 610, Alfol.RTM. 810, Lial.RTM. 125
and Nafol.RTM. types (Sasol); Alphanol.RTM. 79 (ICI); Epal.RTM. 610
and Epal.RTM. 810 (Afton); Linevol.RTM. 79, Linevol.RTM. 911 and
Neodol.RTM. 25E (Shell); Dehydad.RTM., Hydrenol.RTM. and Lorol.RTM.
types (Cognis); Acropol.RTM. 35 and Exxal.RTM. 10 (Exxon
Chemicals); Kalcol.RTM. 2465 (Kao Chemicals).
[0062] Among the ethylenically unsaturated ester compounds, the
(meth)acrylates are particularly preferred over the maleates and
fumarates, i.e. R.sup.2, R.sup.3, R.sup.5, R.sup.6, R.sup.8 and
R.sup.9 of the formulae (I), (II) and (III) in particularly
preferred embodiments are each hydrogen.
[0063] The weight ratio of units derived from ester monomers having
7 to 15 carbon atoms, preferably of the formula (II), to the units
derived from ester monomers having 16 to 40 carbon atoms,
preferably of the formula (III), may be within a wide range. The
weight ratio of repeat units derived from ester monomers having 7
to 15 carbon atoms in the alcohol part to repeat units derived from
ester monomers having 16 to 40 carbon atoms in the alcohol part is
preferably in the range from 5:1 to 1:30, more preferably in the
range from 1:1 to 1:3, especially preferably 1:1.1 to 1:2.
[0064] Component (IV) comprises especially ethylenically
unsaturated monomers which can be copolymerized with the
ethylenically unsaturated ester compounds of the formulae (I), (II)
and/or (III).
[0065] However, particularly suitable comonomers for polymerization
according to the present invention are those which correspond to
the formula:
##STR00004##
in which R.sup.1* and R.sup.2* are each independently selected from
the group consisting of hydrogen, halogens CN, linear or branched
alkyl groups having 1 to 20, preferably 1 to 6 and more preferably
1 to 4, carbon atoms which may be substituted by 1 to (2n+1)
halogen atoms, where n is the number of carbon atoms of the alkyl
group for example CF.sub.3), .alpha.,.beta.-unsaturated linear or
branched alkenyl or alkynyl groups having 2 to 10, preferably 2 to
6 and more preferably 2 to 4, carbon atoms which may be substituted
by 1 to (2n-1) halogen atoms, preferably chlorine, where n is the
number of carbon atoms of the alkyl group, for example
CH.sub.2.dbd.CCl--, cycloalkyl groups having 3 to 8 carbon atoms
which may be substituted by 1 to (2n-1) halogen atoms, preferably
chlorine, where n is the number of carbon atoms of the cycloalkyl
group; C(.dbd.Y*)R.sup.5*, C(.dbd.Y*) NR.sup.5*R.sup.7*,
Y*C(.dbd.Y*)R.sup.b*, SOR.sup.5*, SO.sub.2R.sup.5*,
OSO.sub.2R.sup.5*, NR.sup.8*SO.sub.2R.sup.5*, PR.sup.5*,
P(.dbd.Y*)R.sup.5*.sub.2, Y*PR.sup.5*.sub.2,
Y*P(.dbd.Y*)R.sup.5*.sub.2, NR.sup.8*.sub.2 which may be
quaternized with an additional R.sup.8*, aryl or heterocyclyl
group, where Y* may be NR.sup.8*, S or O, preferably O; R.sup.5* is
an alkyl group having from 1 to 20 carbon atoms, an alkylthio
having 1 to 20 carbon atoms, OR.sup.15 (R.sup.15 is hydrogen or an
alkali metal), alkoxy of 1 to 20 carbon atoms, aryloxy or
heterocyclyloxy; R.sup.6* and R.sup.7* are each independently
hydrogen or an alkyl group having 1 to 20 carbon atoms, or R.sup.6*
and R.sup.7* together may form an alkylene group having 2 to 7,
preferably 2 to 5 carbon atoms, in which case they form a 3- to
8-membered, preferably 3- to 6-membered, ring, and R.sup.8* is
hydrogen, linear or branched alkyl or aryl groups having 1 to 20
carbon atoms;
[0066] R.sup.3* and R.sup.4* are independently selected from the
group consisting of hydrogen, halogen (preferably fluorine or
chlorine), alkyl groups having 1 to 6 carbon atoms and COOR.sup.9*
in which R.sup.9* is hydrogen, an alkali metal or an alkyl group
having 1 to 40 carbon atoms, or R.sup.1* and R.sup.3* together may
form a group of the formula (CH.sub.2).sub.n, which may be
substituted by 1 to 2n' halogen atoms or C.sub.1 to C.sub.4 alkyl
groups, or form the formula C(.dbd.O)--Y*--C(.dbd.O) where n' is 2
to 6, preferably 3 or 4, and Y* is as defined above; and where at
least 2 of the R.sup.1*, R.sup.2*, R.sup.3* and R.sup.4* radicals
are hydrogen or halogen.
[0067] The preferred comonomers (IV) include hydroxyalkyl
(meth)acrylates like 3-hydroxypropyl (meth)acrylate,
3,4-dihydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,
2-hydroxypropyl (meth)acrylate, 2,5-dimethyl-1,6-hexanediol
(meth)acrylate, 1,10-decanediol (meth)acrylate;
aminoalkyl (meth)acrylates and aminoalkyl (meth)acrylamides like
N-(3-dimethylaminopropyl)methacrylamide, 3-diethylaminopentyl
(meth)acrylate, 3-dibutylaminohexadecyl (meth)acrylate; nitriles of
(meth)acrylic acid and other nitrogen-containing (meth)acrylates
like N-(methacryloyloxyethyl)diisobutylketimine,
N-(methacryloyloxyethyl)dihexadecylketimine,
(meth)acryloylamidoacetonitrile,
2-methacryloyloxyethylmethylcyanamide, cyanomethyl (meth)acrylate;
aryl (meth)acrylates like benzyl (meth)acrylate or phenyl
(meth)acrylate, where the acryl residue in each case can be
unsubstituted or substituted up to four times; carbonyl-containing
(meth)acrylates like 2-carboxyethyl (meth)acrylate, carboxymethyl
(meth)acrylate, oxazolidinylethyl (meth)acrylate,
N-methyacryloyloxy)formamide, acetonyl (meth)acrylate,
N-methacryloylmorpholine, N-methacryloyl-2-pyrrolidinone,
N-(2-methyacryloxyoxyethyl)-2-pyrrolidinone,
M-(3-methacryloyloxypropyl)-2-pyrrolidinone,
N-(2-methyacryloyloxypentadecyl(-2-pyrrolidinone,
N-(3-methacryloyloxyheptadecyl-2-pyrrolidinone; (meth)acrylates of
ether alcohols like tetrahydrofurfuryl (meth)acrylate,
methoxyethoxyethyl (meth)acrylate, 1-butoxypropyl (meth)acrylate,
cyclohexyloxyethyl (meth)acrylate, propoxyethoxyethyl
(meth)acrylate, benzyloxyethyl (meth)acrylate, furfuryl
(meth)acrylate, 2-butoxyethyl (meth)acrylate,
2-ethoxy-2-ethoxyethyl (meth)acrylate, 2-methoxy-2-ethoxypropyl
(meth)acrylate, ethoxylated (meth)acrylates, 1-ethoxybutyl
(meth)acrylate, methoxyethyl (meth)acrylate,
2-ethoxy-2-ethoxy-2-ethoxyethyl (meth)acrylate, esters of (meth
acrylic acid and methoxy polyethylene glycols; (meth)acrylates of
halogenated alcohols like 2,3-dibromopropyl (meth)acrylate,
4-bromophenyl (meth)acrylate, 1,3-dichloro-2-propyl (meth)acrylate,
2-bromoethyl (meth)acrylate, 2-iodoethyl (meth)acrylate,
chloromethyl (meth)acrylate; oxiranyl (meth)acrylate like
2,3-epoxybutyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 10,11
epoxyundecyl (meth)acrylate, 2,3-epoxycyclohexyl (meth)acrylate,
oxiranyl (meth)acrylates such as 10,11-epoxyhexadecyl
(meth)acrylate, glycidyl (meth)acrylate; phosphorus-, boron- and/or
silicon-containing (meth)acrylates like 2-(dimethylphosphato)propyl
(meth)acrylate, 2-(ethylphosphito)propyl (meth)acrylate,
2-dimethylphosphinomethyl (meth)acrylate, dimethylphosphonoethyl
(meth)acrylate, diethylmethacryloyl phosphonate,
dipropylmethacryloyl phosphate, 2-(dibutylphosphono)ethyl
(meth)acrylate, 2,3-butylenemethacryloylethyl borate,
methyldiethoxymethacryloylethoxysiliane, diethylphosphatoethyl
(meth)acrylate; sulfur-containing (meth)acrylates like
ethylsulfinylethyl (meth)acrylate, 4-thiocyanatobutyl
(meth)acrylate, ethylsulfonylethyl (meth)acrylate,
thiocyanatomethyl (meth)acrylate, methylsulfinylmethyl
(meth)acrylate, bis(methacryloyloxyethyl) sulfide; heterocyclic
(meth)acrylates like 2-(1-imidazolyl)ethyl (meth)acrylate,
2-(4-morpholinyl)ethyl (meth)acrylate and
1-(2-methacryloyloxyethyl)-2-pyrrolidone; maleic acid and maleic
acid derivatives different from those mentioned under (I), (II) and
(III), for example maleic anhydride, methylmaleic anhydride,
maleimide, methylmaleimide; fumaric acid and fumaric acid
derivatives different from those mentioned under (I), (II) and
(III); vinyl halides such as, for example, vinyl chloride, vinyl
fluoride, vinylidene chloride and vinylidene fluoride; vinyl esters
like vinyl acetate; vinyl monomers containing aromatic groups like
styrene, substituted styrenes with an alkyl substituent in the side
chain, such as .alpha.-methylstyrene and .alpha.-ethylstyrene,
substituted styrenes with an alkyl substituent on the ring such as
vinyltoluene and p-methylstyrene, halogenated styrenes such as
monochlorostyrenes, dichlcrostyrenes, tribromostyrenes and
tetrabromostyrenes; heterocyclic vinyl compounds like
2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine,
3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine,
vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole,
3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole,
2-methyl-1-vinylimidazole, N-vinylpyrrolidone, 2-vinylpyrrolidone,
N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam,
N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene,
vinylthiolane, vinylthiazoles and hydrogenated vinylthiazoles,
vinyloxazoles and hydrogenated vinyloxazoles; vinyl and isoprenyl
ethers; methacrylic acid and acrylic acid.
[0068] The proportion of comonomers (IV) can be varied depending on
the use and property profile of the polymer. In general, this
proportion may be in the range from 0 to 60% by weight, preferably
from 0.01 to 20% by weight and more preferably from 0.1 to 10% by
weight. Owing to the combustion properties and for ecological
reasons, the proportion of the monomers which comprise aromatic
groups, heteroaromatic groups, nitrogen-containing groups,
phosphorus-containing groups and sulphur-containing groups can be
minimized. The proportion of these monomers can therefore be
restricted to 1% by weight, in particular 0.5% by weight and
preferably 0.01% by weight.
[0069] The comonomers (IV) and the ester monomers of the formulae
(I), (II) and (III) can each be used individually or as
mixtures.
[0070] Surprising advantages can be achieved, inter alia, with
polymers comprising ester groups which comprise repeating units
which are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols. The hydroxyl-containing monomers
include hydroxyalkyl (meth) acrylates and vinyl alcohols. These
monomers have been disclosed in detail above.
[0071] The polymers comprising ester groups for use in accordance
with the invention have a number average molecular weight in the
range of 750 to 100 000 g/mol, preferably in the range of 2 000 to
70 000 g/mol and more preferably in the range of 5 000 to 40 000
g/mol. Preferably, the weight average molecular weight of the
polymers comprising ester groups for use in accordance with the
invention is in the range of 1000 to 60000 g/mol, more preferably
in the range of 5000 to 50000 g/mol.
[0072] As mentioned above, the number average molecular weight Mn
and the weight average molecular weight Mw can be determined via
GPC using a methyl methacrylate polymer as standard.
[0073] The preferred copolymers which can be obtained by
polymerizing unsaturated ester compounds preferably have a
polydispersity M.sub.w/M.sub.n in the range of 1 to 8, more
preferably 1.05 to 6.0 and most preferably 1.2 to 5.0. This
parameter can be determined by GPC as mentioned above and
below.
[0074] According to a special embodiment of the present invention
the additive for improving the filterability comprises at least two
polyalkyl(meth)acrylate polymers.
[0075] If the additive for improving the filterability comprises at
least two polyalkyl(meth)acrylate polymers one of the
polyalkyl(meth)acrylate polymers preferably comprises repeating
units which are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols. The polyalkyl(meth)acrylate
polymer comprising repeating units which are derived from
hydroxyl-containing monomers and/or (meth)acrylates of ether
alcohols further includes repeating units derived from ester
monomers having 7 to 40 carbon atoms in the alcohol part.
Preferably, the polymer having repeating units which are derived
from hydroxyl-containing monomers and/or (meth)acrylates of ether
alcohols comprises at least 40% by weight, especially at least 60%
by weight and more preferably at least 80% by weight of repeating
units derived from ester monomers having 7 to 40 carbon atoms, more
preferably 7 to 15 carbon atoms in the alcohol part. In particular,
the polymer having repeating units which are derived from
hydroxyl-containing monomers and/or (meth)acrylates of ether
alcohols may comprise 0.1 to 40% by weight, especially 1 to 20% by
weight and more preferably 4 to 12% by weight of repeating units
which are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols as mentioned above. The
hydroxyl-containing monomers include hydroxyalkyl (meth)acrylates
and vinyl alcohols. These monomers have been disclosed in detail
above.
[0076] In addition to the polyalkyl(meth)acrylate polymer
comprising repeating units which are derived from
hydroxyl-containing monomers and/or (meth)acrylates of ether
alcohols preferred additives for improving the filterability
further includes polyalkyl(meth)acrylate polymers comprising
repeating units being derived from alkyl (meth)acrylates having 16
to 40 carbon atoms in the alkyl residue.
[0077] As mentioned above, preferred additives for improving the
filterability comprises at least two polyalkyl(meth)acrylate
polymers wherein one of the polymers have a higher content of
repeating units which are derived from hydroxyl-containing monomers
and/or (meth)acrylates of ether alcohols than the other.
Accordingly, preferred polyalkyl(meth)acrylate polymers comprising
repeating units being derived from alkyl (meth)acrylates having 16
to 40 carbon atoms in the alkyl residue for use with preference in
the inventive fuel mixtures preferably contain at most 5% by
weight, preferably at most 3% by weight, more preferably at most 1%
by weight and most preferably at most 0.1% by weight of units which
are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols.
[0078] According to a preferred aspect of the present invention,
the polyalkyl(meth)acrylate polymers comprising repeating units
which are derived from hydroxyl-containing monomers and/or
(meth)acrylates of ether alcohols preferably have a lower molecular
weight than the other polyalkyl(meth)acrylate polymer.
[0079] Particularly, the weight ratio of said
polyalkyl(meth)acrylate polymers comprising a repeating units being
derived from alkyl (meth)acrylates having 16 to 40 carbon atoms in
the alkyl residue to said polyalkyl(meth)acrylate polymers
comprising repeating units which are derived from
hydroxyl-containing monomers and/or (meth)acrylates of ether
alcohols have a lower molecular weight is in the range from 10:1 to
1:10, more preferably in the range from 3:1 to 1:3.
[0080] The architecture of the polymers comprising ester groups is
not critical for many applications and properties. Accordingly, the
polymers comprising ester groups may be random copolymers, gradient
copolymers, block copolymers and/or graft copolymers.
[0081] Block copolymers and gradient copolymers can be obtained,
for example, by altering the monomer composition discontinuously
during the chain growth. The blocks derived from ester compounds of
the formulae (I), (II) and/or (III) preferably have at least 10 and
more preferably at least 30 monomer units.
[0082] The preparation of the polyalkyl esters from the
above-described compositions is known per se. Thus, these polymers
can be obtained in particular by free-radical polymerization and
related processes, for example ATRP (=Atom Transfer Radical
Polymerization) or RAFT (=Reversible Addition Fragmentation Chain
Transfer).
[0083] Customary free-radical polymerization is described, inter
alia, in Ullmann's Encyclopedia of Industrial Chemistry, Sixth
Edition. In general, a polymerization initiator and a chain
transfer agent are used for this purpose. The usable initiators
include the azo initiators widely known in the technical field,
such as AIBN and 1,1-azobiscyclohexane-carbonitrile, and also
peroxy compounds such as methyl ethyl ketone peroxide,
acetylacetone peroxide, dilauryl peroxide, tert-butyl
per-2-ethylhexanoate, ketone peroxide, tert-butyl peroctoate,
methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl
peroxide, tert-butyl peroxybenzoate, tert-butyl
peroxyisopropylcarbonate,
2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butyl
peroxy-2-ethylhexanoate, tert-butyl
peroxy-3,5,5-trimethylhexanoate, dicumyl peroxide,
1,1-bis(tert-butylperoxy)cyclohexane,
1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumyl
hydroperoxide, tert-butyl hydroperoxide,
bis(4-tert-butylcyclohexyl) peroxydicarbonate, mixtures of two or
more of the aforementioned compounds with one another, and mixtures
of the aforementioned compounds with compounds which have not been
mentioned but can likewise form free radicals. Suitable chain
transfer agents are in particular oil-soluble mercaptans, for
example n-dodecyl mercaptan or 2-mercaptoethanol, or else chain
transfer agents from the class of the terpenes, for example
terpinolene.
[0084] The ATRP process is known per se. It is assumed that it is a
"living" free-radical polymerization, without any intention that
the description of the mechanism should impose a restriction. In
these processes, a transition metal compound is reacted with a
compound which has a transferable atom group. This transfers the
transferable atom group to the transition metal compound, which
oxidizes the metal. This reaction forms a radical which adds onto
ethylenic groups. However, the transfer of the atom group to the
transition metal compound is reversible, so that the atom group is
transferred back to the growing polymer chain, which forms a
controlled polymerization system. The structure of the polymer, the
molecular weight and the molecular weight distribution can be
controlled correspondingly.
[0085] This reaction is described, for example, by J-S. Wang, et
al., J. Am. Chem. Soc., vol. 117, p. 5614-5615 (1995), by
Matyjaszewski, Macromolecules, vol. 28, p. 7901-7910 (1995). In
addition, the patent applications WO 96/30421, WO 97/47661, WO
97/18247, WO 98/40415 and WO 99/10387 disclose variants of the ATRP
explained above.
[0086] In addition, the inventive polymers may be obtained, for
example, also via RAFT methods. This process is presented in
detail, for example, in WO 98/01478 and WO 2004/083169, to which
reference is made explicitly for the purposes of disclosure.
[0087] In addition, the inventive polymers are obtainable by NMP
processes (nitroxide-mediated polymerisation), which are described,
inter alia, in U.S. Pat. No. 4,581,429.
[0088] These methods are described comprehensively, in particular
with further references, inter alia, in K. Matyjaszewski, T. P.
Davis, Handbook of Radical Polymerization, Wiley Interscience,
Hoboken 2002, to which reference is made explicitly for the
purposes of disclosure.
[0089] The polymerization may be carried out at standard pressure,
reduced pressure or elevated pressure. The polymerization
temperature is generally in the range of -20.degree.-200.degree.
C., preferably 0.degree.-160.degree. C. and more preferably
63.degree.-140.degree. C.
[0090] The polymerization may be carried out with or without
solvent. The term solvent is to be understood here in a broad
sense.
[0091] The polymerization is preferably carried out in a nonpolar
solvent. These include hydrocarbon solvents, for example aromatic
solvents such as toluene, benzene and xylene, saturated
hydrocarbons, for example cyclohexane, heptane, octane, nonane,
decane, dodecane, which may also be present in branched form. These
solvents may be used individually and as a mixture. Particularly
preferred solvents are mineral oils, diesel fuels of mineral
origin, natural vegetable and animal oils, biodiesel fuels and
synthetic oils (e.g. ester oils such as dinonyl adipate), and also
mixtures thereof. Among these, very particular preference is given
to mineral oils and mineral diesel fuels.
[0092] The inventive fuel composition may comprise further
additives in order to achieve specific solutions to problems. These
additives include dispersants, for example wax dispersants and
dispersants for polar substances, demulsifiers, defoamers,
lubricity additives, antioxidants, cetane number improvers,
detergents, dyes, corrosion inhibitors and/or odorants.
[0093] For example, the inventive fuel composition may comprise
ethylene copolymers which are described, for example, in EP-A-1 541
663. These ethylene copolymers may contain 8 to 21 mol % of one or
more vinyl and/or (meth)acrylic esters and 79 to 92% by weight of
ethylene. Particular preference is given to ethylene copolymers
containing 10 to 18 mol % and especially 12 to 16 mol % of at least
one vinyl ester. Suitable vinyl esters derive from fatty acids
having linear or branched alkyl groups having 1 to 30 carbon atoms.
Examples include vinyl acetate, vinyl propionate, vinyl butyrate,
vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl laurate
and vinyl stearate, and also esters of vinyl alcohol based on
branched fatty acids, such as vinyl isobutyrate, vinyl pivalate,
vinyl 2-ethylhexanoate, vinyl isononanoate, vinyl neononanoate,
vinyl neodecanoate and vinyl neoundecanoate. Comonomers which are
likewise suitable are esters of acrylic acid and methacrylic acid
having 1 to 20 carbon atoms in the alkyl radical, such as methyl
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n- and
isobutyl (meth)acrylate, hexyl (meth)acrylate, octyl
(meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate,
dodecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl
(meth)acrylate, octadecyl (meth)acrylate, and also mixtures of two,
three or four or else more of these comonomers.
[0094] Particularly preferred terpolymers of vinyl
2-ethylhexanoate, of vinyl neononanoate and of vinyl neodecanoate
contain, apart from ethylene, preferably 3.5 to 20 mol %, in
particular 8 to 15 mol %, of vinyl acetate and 0.1 to 12 mol %, in
particular 0.2 to 5 mol %, of the particular long-chain vinyl
ester, the total comonomer content being between 8 and 21 mol %,
preferably between 12 and 18 mol %. Further preferred copolymers
contain, in addition to ethylene and 8 to 18 mol % of vinyl esters,
also 0.5 to 10 mol % of olefins such as propene, butene,
isobutylene, hexene, 4-methylpentene, ceteris, diisobutylene and/or
norbornene.
[0095] The ethylene copolymers preferably have molecular weights
which correspond to melt viscosities at 140.degree. C. of from 20
to 10 000 mPas, in particular 30 to 5000 mPas and especially 50 to
1000 mPas. The degrees of branching determined by means of .sup.1H
NMR spectroscopy are preferably between 1 and 9 CH.sub.3/100
CH.sub.2 groups, in particular between 2 and 6 CH.sub.3/100
CH.sub.2 groups, for example 2.5 to 5 CH.sub.3/100 CH.sub.2 groups,
which do not stem from the comonomers.
[0096] Such ethylene copolymers are described in detail, inter
alia, in DE-A-34 43 475, EP-B-0 203 554, EP-B-0 254 284, EP-B-0 405
270, EP-B-0 463 518, EP-B-0 493 769, EP-0 778 875, DE-A-196 20 118,
DE-A-196 20 119 and EP-A-0 926 168.
[0097] Preference is given in this context to ethylene-vinyl
acetate copolymers and terpolymers which, in addition to ethylene
and vinyl acetate repeat units, also have repeat (meth)acrylic
ester units. These polymers may be structured, for example, as
random copolymers, as block copolymers or as graft copolymers.
[0098] In a preferred embodiment, the inventive fuel composition
may comprise 0.0005 to 2% by weight, preferably 0.01 to 0.5% by
weight, of ethylene copolymers.
[0099] For reasons of cost, however, a proportion of the
above-described ethylene copolymers can be dispensed with in a
further embodiment, in which case these fuel compositions without a
significant proportion of ethylene copolymers have outstanding
properties. In this specific embodiment, the proportion of ethylene
copolymers may preferably be at most 0.05% by weight, more
preferably at most 0.001% by weight and most preferably at most
0.0001% by weight.
[0100] The fuel composition of the present invention may comprise
diesel fuel of mineral origin, i.e. diesel, gas oil or diesel oil.
Mineral diesel fuel is widely known per se and is commercially
available. This is understood to mean a mixture of different
hydrocarbons which is suitable as a fuel for a diesel engine.
Diesel can be obtained as a middle distillate, in particular by
distillation of crude oil. The main constituents of the diesel fuel
preferably include alkanes, cycloalkanes and aromatic hydrocarbons
having about 10 to 22 carbon atoms per molecule. A few longer chain
n-paraffins up to 36 carbon atoms may typically be present and may
significantly influence the cold flow properties of Diesel
fuels.
[0101] Preferred diesel fuels of mineral origin boil in the range
of 120.degree. C. to 450.degree. C., more preferably 170.degree. C.
and 390.degree. C. Preference is given to using those middle
distillates which contain 0.05% by weight of sulphur and less, more
preferably less than 350 ppm of sulphur, in particular less than
200 ppm of sulphur and in special cases less than 50 ppm of
sulphur, for example less than 10 ppm of sulphur. They are
preferably those middle distillates which have been subjected to
refining under hydrogenating conditions, and which therefore
contain only small proportions of polyaromatic and polar compounds.
They are preferably those middle distillates which have 95%
distillation points below 370.degree. C., in particular below
350.degree. C. and in special cases below 330.degree. C. Synthetic
fuels, as obtainable, for example, by the Fischer-Tropsch process
or gas to liquid processes (GTL), are also suitable as diesel fuels
of mineral origin.
[0102] The kinematic viscosity of diesel fuels of mineral origin to
be used with preference is in the range of 0.5 to 8 mm.sup.2/s,
more preferably 1 to 5 mm.sup.2/s, and especially preferably 1.5 to
3 mm.sup.2/s, measured at 40.degree. C. to ASTM D 445.
[0103] For reasons of environmental protection, the proportion of
diesel fuels of mineral origin may preferably be limited to at most
95% by weight, especially at most 90% by weight, more preferably at
most 80% by weight, particularly at most 60% by weight and most
preferably at most 15% by weight.
[0104] The present fuel oil composition comprises an excellent
filterability according to ASTM D 7501 as described above.
Preferably, the biodiesel comprises a CSFT value of at most 300 ml
after 350 seconds with an effective amount of said additive for
improving the filterability. In particularly the 300 ml volume can
be achieved after a period of time of at most 300 seconds, more
preferably after a period of time of at most 200 seconds.
[0105] The inventive fuel compositions have outstanding
low-temperature properties. More particularly, the pour point (PP)
to ASTM D97 preferably has values less than or equal to 18.degree.
C., preferably less than or equal to 0.degree. C. and more
preferably less than or equal to -12.degree. C. Based on the
biodiesel fuel without addition of polymers for use in accordance
with the invention, it is unexpectedly possible to achieve
improvements in the pour point of 3.degree. C., preferably
6.degree. C. and most preferably >6.degree. C.
[0106] The limit of the cold filter plugging point (CFPP) measured
to DIN EN 116 is preferably at most 16.degree. C., more preferably
at most 0.degree. C. and more preferably at most -12.degree. C. In
addition, the cloud point (CP) to ASTM D2500 of preferred fuel
compositions may assume values less than or equal to 16.degree. C.,
preferably less than or equal to 0.degree. C. and more preferably
less than or equal to -12.degree. C.
[0107] Usually fuel oil compositions comprise at least 70% by
weight, more preferably at least 90% by weight and most preferably
at least 98% by weight fuel oil. Useful fuel oils include diesel
fuel of mineral origin and biodiesel fuel oil.
[0108] The inventive fuel compositions preferably have an iodine
number of at most 30, more preferably at most 20 and most
preferably at most 10.
[0109] The cetane number to DIN 51773 of inventive fuel
compositions is preferably at least 50, more preferably at least
53, in particular at least 55 and most preferably at least 58.
[0110] The viscosity of the present fuel compositions may be within
a wide range, and this feature can be adjusted to the intended use.
This adjustment can be effected, for example, by selecting the
biodiesel fuels or the mineral diesel fuels. In addition, the
viscosity can be varied by the amount and the molecular weight of
the ester-comprising polymers used. The kinematic viscosity of
preferred fuel compositions of the present invention is in the
range of 1 to 10 mm.sup.2/s, more preferably 2 to 5 mm.sup.2/s and
especially preferably 2.5 to 4 mm.sup.2/s, measured at 40.degree.
C. to ASTM D445.
[0111] The use a polyalkyl(meth)acrylate polymer having a number
average molecular weight Mn of from 750 to 10000 g/mol and a
polydispersity Mw/Mn of from 1 to 8 to improve the filterability of
a fuel oil comprising a biodiesel accordingly provides fuel
compositions with exceptional properties. Regarding such aspect a
low purified biodiesel can be used in order to meet the
requirements of ASTM D 7501.
[0112] In addition thereto the present invention provides a method
for improving the filterability of a fuel oil comprising a
biodiesel wherein an additive for improving the filterability is
added to said fuel oil composition. Especially a
polyalkyl(meth)acrylate polymer having a number average molecular
weight Mn of from 750 to 100000 g/mol and a polydispersity Mw/Mn of
from 1 to 8 can be added as an additive for improving the
filterability to the fuel oil compositions.
[0113] The invention will be illustrated in detail hereinafter with
reference to examples and comparative examples, without any
intention that this should impose a restriction. Unless otherwise
specified, the percentages are weight percent.
EXAMPLES AND COMPARATIVE EXAMPLE
General Method for Preparing the Polymers
[0114] 600 g of monomer composition according to the composition
detailed in each case in Table 1 and n-dodecyl mercaptan (20 g to 2
g depending on the desired molecular weight) are mixed. 44.4 g of
this monomer/regulator mixture are charged together with 400 g of
carrier oil (e.g. 100N mineral oil, synthetic dinonyl adipate or
vegetable oil) into the 2 l reaction flask of an apparatus with
sabre stirrer, condenser, thermometer, feed pump and N.sub.2 feed
line. The apparatus is inertized and heated to 100.degree. C. with
the aid of an oil bath. The remaining amount of 555.6 g of
monomer/regulator mixture is admixed with 1.4 g of tert-butyl
peroctoate. Once the mixture in the reaction flask has attained a
temperature of 100.degree. C., 0.25 g of tert-butyl peroctoate is
added, and the feed of the monomer/regulator/initiator mixture by
means of a pump is started simultaneously. The addition is effected
uniformly over a period of 210 min at 100.degree. C. 2 h after the
end of feeding, another 1.2 g of tert-butyl peroctoate are added
and the mixture is stirred at 100.degree. C. for a further 2 h. A
60% clear concentrate is obtained.
[0115] The mass-average molecular weight M.sub.w and the
polydispersity index PDI of the polymers were determined by GPC.
The measurements were effected in tetrahydrofuran at 35.degree. C.
against a polymethyl methacrylate calibration curve composed of a
set of .gtoreq.25 standards (Polymer Standards Service or Polymer
Laboratories), whose M.sub.peck was distributed in a
logarithmically uniform manner over the range of 5.times.10.sup.6
to 2.times.10.sup.2 g/mol. A combination of six columns (Polymer
Standards Service SDV 100 .ANG./2.times.SDV LXL/2.times.SDV 100
.ANG./Shodex KF-800D) was used. To record the signal, an R.sup.1
detector (Agilent 1100 Series) was used.
TABLE-US-00001 TABLE 1 Properties of the polymers used Monomer
composition (weight Mw PDI Polymer ratio) [g/mol] (Mw/Mn) PAMA 1
SMA-LMA-DPMA 40 000 2.0 60.4-39.4-0.2 PAMA 2 DPMA-LIMA-MMA-SMA-HEMA
22 000 2.0 88.45-0.55-1.0-1.0-9.0 SMA: alkyl methacrylate which has
16 to 18 carbon atoms in the alkyl part LMA: alkyl methacrylate
which has about 10 carbon atoms in the alkyl part, the alkyl part
being predominantly linear LIMA alkyl methacrylate which has 12 to
15 carbon atoms in the alkyl part (prepared from Sasol's .RTM. LIAL
125) DPMA: alkyl methacrylate which has 12 to 15 carbon atoms in
the alkyl part (prepared from Shell's .RTM. Neodol 25 E) MMA methyl
methacrylate HEMA: 2-hydroxyethyl methacrylate
[0116] Subsequently, the polymers thus obtained were studied in a
biodiesel composition derived from canola oil. The biodiesel
comprised about 63.1% octadecenoic acid methyl ester (especially
oleic acid methyl ester); about 18.0% octadecadienoic acid methyl
ester (especially linoleic acid methyl ester); about 8.3%
octadecatrienoic acid methyl ester (especially linolenic acid
methyl ester); about 4.1% hexadecanoic acid methyl ester
(especially palmitic acid methyl ester); about 2.1% octadecanoic
acid methyl ester (especially stearic acid methyl ester); about
1.4% eicosanoic acid methyl ester (especially arachidic acid methyl
ester); and the residue was formed by other saturated and
unsaturated fatty acid methyl esters in amounts below 1%. The
analysis was made by gas chromatography (GC) and the % is based on
the peak area of the chromatogram.
[0117] To study the filterability of the compositions, the Cold
Soak Filter Test (CSFT) value of the fuel compositions according to
ASTM D 7501 was determined.
TABLE-US-00002 TABLE 3 CSFT value of fuel the compositiors Additive
Filtered (polymer Amount Filter time volume according to) [% by
weight] [s] [ml] No No 720 250 PAMA 1 0.1 508 300 PAMA 1 0.25 324
300 PAMA 1 and 0.25 113 300 PAMA 2 (50 to 50 mixture by weight)
PAMA 1 and 0.5 141 300 PAMA 2 (50 to 50 mixture by weight)
[0118] The Examples clearly show that the filterability of a
biodiesel can be improved astonishingly. While the additive
consisting of alkylmethacrylates according to Example 1 can improve
the CSFT value significantly, a mixture of polymers PAMA 1 and PAMA
2 as mentioned above show a surprising synergistic effect.
* * * * *