U.S. patent application number 10/408138 was filed with the patent office on 2004-02-05 for jet fuel compositions.
Invention is credited to Armitage, Phillip, Jackson, Graham, Tack, Robert D..
Application Number | 20040020106 10/408138 |
Document ID | / |
Family ID | 8185682 |
Filed Date | 2004-02-05 |
United States Patent
Application |
20040020106 |
Kind Code |
A1 |
Tack, Robert D. ; et
al. |
February 5, 2004 |
Jet fuel compositions
Abstract
Jet fuel compositions having good low temperature operability.
The jet fuel compositions comprise a jet fuel and at least one of
the following additives: (i) a copolymer of ethylene and at least
one unsaturated ester selected from: vinyl esters having at least 5
carbon atoms, alkyl (meth)acrylates, di-alkyl fumarates and
di-alkyl maleates; (ii) a copolymer of ethylene and alkene; (iii) a
copolymer of ethylene and less than 15 mole percent of vinyl
acetate; (iv) a nucleator; (v) a wax; (vi) a substantially branched
alkyl phenol formaldehyde condensate; (vii) a comb polymer; and
(viii) a polar nitrogen compound.
Inventors: |
Tack, Robert D.;
(Oxfordshire, GB) ; Jackson, Graham; (Berkshire,
GB) ; Armitage, Phillip; (Berkshire, GB) |
Correspondence
Address: |
Infineum USA L.P.
Law Department
1900 East Linden Avenue
P. O. Box 710
Linden
NJ
07036-0710
US
|
Family ID: |
8185682 |
Appl. No.: |
10/408138 |
Filed: |
April 7, 2003 |
Current U.S.
Class: |
44/393 ; 44/395;
44/408; 44/418 |
Current CPC
Class: |
C10L 1/165 20130101;
C10L 1/232 20130101; C10L 1/1691 20130101; C10L 1/143 20130101;
C10L 1/238 20130101; C10L 1/195 20130101; C10L 1/1852 20130101;
C10L 1/224 20130101; C10L 1/1963 20130101; C10L 1/1985 20130101;
C10L 1/2222 20130101; C10L 1/1973 20130101; C10L 1/221 20130101;
C10L 1/2286 20130101; C10L 1/1658 20130101; C10L 1/146 20130101;
C10L 1/1641 20130101; C10L 1/2383 20130101; C10L 1/1966 20130101;
C10L 1/1981 20130101 |
Class at
Publication: |
44/393 ; 44/395;
44/408; 44/418 |
International
Class: |
C10L 001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 16, 2002 |
EP |
02252680.0 |
Jul 4, 2002 |
GB |
0215418.5 |
Claims
1. A jet fuel composition comprising a jet fuel and at least one of
the following additives: (i) a copolymer of ethylene and at least
one unsaturated ester selected from the group consisting of vinyl
esters having at least 5 carbon atoms, alkyl (meth)acrylates,
di-alkyl fumarates and dialkyl maleates; (ii) a copolymer of
ethylene and alkene; (iii) a copolymer of ethylene and less than 15
mole percent of vinyl acetate; (iv) a nucleator; (v) a wax; (vi) a
substantially branched alkyl phenol formaldehyde condensate; (vii)
a comb polymer; and (viii) a polar nitrogen compound.
2. The jet fuel composition as claimed in claim 1, comprising jet
fuel and an additive combination of at least one copolymer selected
from the group consisting of (i), (ii) or (iii), at least one polar
nitrogen compound (viii) and optionally at least one nucleator
(iv).
3. The jet fuel composition as claimed in claim 1, comprising jet
fuel and an additive combination of at least one copolymer selected
from (i), (ii) or (iii), at least one comb polymer (vii) and
optionally at least one nucleator (iv).
4. The jet fuel composition as claimed in claim 1, comprising jet
fuel and an additive combination of at least one polar nitrogen
compound (viii) and at least one comb polymer (vii).
5. The jet fuel composition as claimed in claim 1, comprising jet
fuel and an additive combination of at least one polar nitrogen
compound (viii) and at least one substantially branched alkyl
phenol formaldehyde condensate (vi).
6. The jet fuel composition as claimed in claim 1, comprising jet
fuel and an additive combination of at least one polar nitrogen
compound (viii) and at least one nucleator (iv).
7. The jet fuel composition as claimed in claims 1-6, wherein the
additive or additive combination is present in the jet fuel
composition in an amount ranging from 10 to 20,000 ppm (parts
additive per million parts fuel).
8. The jet fuel composition as claimed in claims 1-6, wherein the
jet fuel is selected from the group consisting of Jet A, Jet A-1,
Jet B, MIL JP 5, MIL JP 7, MIL JP 8 and MIL JP 4.
9. The jet fuel composition as claimed in claim 1, wherein the
copolymer of ethylene and at least one unsaturated ester (i) is a
copolymer of ethylene and at least one vinyl ester (i) having the
formula: --CR.sup.1R.sup.2--CHR.sup.3 wherein R.sup.2 represents
hydrogen or a methyl group; R.sup.1 represents a --OOCR.sup.4 group
wherein R.sup.4 represents a C.sub.1 to C.sub.28 straight or
branched chain alkyl group; R.sup.3 represents hydrogen or alkyl;
and the vinyl ester having at least 5 carbon atoms.
10. The jet fuel composition as claimed in claim 9, wherein the
vinyl ester is selected from the group consisting of vinyl
propionate, vinyl butyrate, vinyl hexanoate, vinyl
2-ethylhexanoate, vinyl octanoate, vinyl benzoate and neo acid
vinyl esters.
11. The jet fuel composition as claimed in claim 1, wherein the
copolymer of ethylene and at least one unsaturated ester (i) has a
molar ethylene content of between 50 and 95 mole percent.
12. The jet fuel composition as claimed in claim 1, wherein the
copolymer of ethylene and alkene (ii) is a copolymer of ethylene
and 1-alkene having at most 20 carbon atoms the 1-alkene being
selected from the group consisting of propylene, 1-butene,
1-hexene, 1-octene, methyl-1-pentene, 1decene, 1-dodecene,
1-tridecene, 1-tetradecene, 1-pentadecene, 1hexadecene,
1-octadecene, 1-eicosene and vinyl-cyclohexane and mixtures
thereof.
13. The jet fuel composition as claimed in claim 1, wherein the
copolymer of ethylene and alkene (ii) has a molar ethylene content
of between 50 and 90 mole percent.
14. The jet fuel composition as claimed in claim 1, wherein the
copolymer of ethylene and less than 15 mole percent of vinyl
acetate (iii) includes less than 14 mole percent of vinyl
acetate.
15. The jet fuel composition as claimed in claim 1, wherein the
nucleator (iv) is a polyoxyalkylene compound.
16. The jet fuel composition as claimed in claim 1, wherein the
nucleator (iv) is a block copolymer comprising a single
crystallizable block and a single non-crystallizable block.
17. The jet fuel composition as claimed in any claim 1, wherein the
wax (v) includes normal and non-normal paraffin hydrocarbons.
18. The jet fuel composition as claimed in claim 1, wherein the
substantially branched alkyl phenol formaldehyde condensate (vi) is
an iso-nonyl phenol formaldehyde condensate or an iso-dodecyl
phenol formaldehyde condensate.
19. The jet fuel composition as claimed in claim 1, wherein the
comb polymer (vii) has the general formula: 9where D represents
R.sup.11, COOR.sup.10, OCOR.sup.10, R.sup.11COOR.sup.10 or
R.sup.10; E represents H or D; G represents H or D; J represents H,
R.sup.11, R.sup.11COOR.sup.10, or a substituted or unsubstituted
aryl or heterocyclic group; K represents H, COOR.sup.11,
OCOR.sup.11, OR.sup.11 or COOH; L represents H, R.sup.11,
COOR.sup.11, OCOR.sup.11 or substituted or unsubstituted aryl;
R.sup.10 representing a hydrocarbyl group having 10 or more carbon
atoms, and R.sup.11 representing a hydrocarbylene (divalent) group
in the R.sup.11COOR.sup.10 moiety and otherwise a hydrocarbyl
(monovalent) group, and m and n represent mole ratios, their sum
being 1 and m being finite and being up to and including 1 and n
being from zero to less than 1, m being within the range of from
1.0 to 0.4 and n being in the range of from 0 to 0.6.
20. The jet fuel composition as claimed in claim 1, wherein the
comb polymer (vii) is a poly-1-alkene.
21. The jet fuel composition as claimed in claim 1, wherein the
comb polymer (vii) is a copolymer of at least one C.sub.4-C.sub.6
1-alkene and at least one C.sub.10-C.sub.14 1-alkene.
22. The jet fuel composition as claimed in claim 1, wherein the
comb polymer (vii) is a mixture of one or more comb polymers
selected from the group of poly-1-alkenes and copolymers of at
least one C.sub.4-C.sub.6 1-alkene and at least one
C.sub.10-C.sub.14 1-alkene.
23. The jet fuel composition as claimed in claim 1, wherein the
comb polymer (vii) is C.sub.8-C.sub.12 dialkylfumarate-vinyl
acetate copolymer.
24. The jet fuel composition as claimed in claim 1, wherein the
polar nitrogen compound (viii) carries one or more amino
substituents selected from the group consisting of mono- or
di-dodecylamino, mono- or di-tetradecylamino, mono- or di-cocoamino
and mono- or di-hydrogenated tallow amine.
25. A process for reducing the pour point of jet fuels, the process
including the following steps: a) providing a jet fuel; and b)
adding at least one of the additives (i) to (viii) defined above in
claim 1 to the jet fuel.
Description
[0001] This invention concerns improved jet fuel compositions, in
particular, jet fuel compositions that are suitable for use at low
temperatures, such as, for example, below -40.degree. C. or
-50.degree. C.
[0002] The most commonly used jet fuels are Jet A and Jet A-1,
which have specification maximum freezing points of -40.degree. C.
and -47.degree. C. respectively. At temperatures below the freezing
point of jet fuel, hydrocarbon molecules crystallize and
precipitate out. Normal paraffins in jet fuel have the highest
crystallization temperatures and are therefore the first to come
out of solution as wax crystals. As the hydrocarbon molecules
crystallize, the viscosity of the fuel increases, which reduces the
flow of the fuel. In Boeing aircraft the fuel temperature must
remain at least 3.degree. C. above the specification freezing point
and in Airbus aircraft the fuel temperature must remain at least
4.degree. C. above the specification freezing point. If the fuel
temperature starts to approach the specification freezing point,
action must be taken to avoid any further cooling. This action
usually involves flying around cold areas, lowering the aircraft to
warmer temperatures or increasing the speed of the aircraft to
increase aerodynamic warming. In extreme cases it may be necessary
to increase the speed and to lower the aircraft. One drawback of
this action is that it usually increases fuel consumption. Studies
have been carried out to consider the use of heated tanks; however,
this would increase the weight of the aircraft and also increase
the fuel consumption.
[0003] Currently freezing points of jet fuel are controlled in
refineries during distillation. Lowering the freezing point can be
achieved by reducing the heavy fractions, which include the waxy
fractions, to whatever level is required; however, reducing the
heavy fractions has a major negative effect on availability. It has
been suggested that switching from Jet A to Jet A-1 could reduce
the available volume by 8%.
[0004] Jet A-1 is the standard specified jet fuel in Europe and is
usually required for winter conditions and routes such as
trans-arctic. Jet A is usually used on flights within the USA.
[0005] Temperatures below 0.degree. C. also cause water present in
the fuel to freeze, which can cause plugging of filters and other
small orifices, and occasionally engine flameout. Ground-based
water-separators are used to control the amount of water present in
a fuel and it is important that additives added to jet fuel do not
block or disarm the filters in these separators. ASTM D 3948-93 is
a test method that can be used to determine the ability of
filter-separators to separate free water from fuel.
[0006] WO 01/62874 discloses the use of compounds capable of
lowering the freeze point of an aviation fuel. The compounds are
selected from:
[0007] (1) the reaction product of an alkanol amine with a
hydrocarbyl-substituted acylating agent;
[0008] (2) the reaction product of a substantially linear
hydrocarbyl-substituted phenol with an aldehyde;
[0009] (3) aromatic moieties containing 1 to 3 aromatic rings;
and
[0010] (4) ethylene vinyl acetate copolymers including from 15 to
35 mole percent of vinyl acetate.
[0011] In the examples in WO 01/62874, the best result is achieved
using an ethylene vinyl acetate copolymer including from 15 to 35
mole percent of vinyl acetate (see Table I in WO 01/62874).
Ethylene vinyl acetate copolymers including from 15 to 35 mole
percent of vinyl acetate have been used as comparative examples
below.
[0012] An aim of this invention is to provide jet fuel compositions
that are suitable for use at low temperatures such as, for example,
below -40.degree. C., preferably below -50.degree. C. In
particular, an aim of this invention is to provide jet fuel
compositions that are suitable for use at temperatures below their
specification freezing points.
[0013] A further aim of this invention is to provide additives that
are more effective at reducing the low temperature operability of
jet fuels than the additives disclosed in WO 01/62874.
[0014] A further aim of this invention is to provide jet fuel
compositions that are suitable for use at temperatures below their
freezing points and do not block or disarm filters in
water-separators.
[0015] In accordance with the present invention there is provided a
jet fuel composition comprising a jet fuel and at least one of the
following additives:
[0016] (i) a copolymer of ethylene and at least one unsaturated
ester selected from: vinyl esters having at least 5 carbon atoms,
alkyl (meth)acrylates, dialkyl fumarates and di-alkyl maleates;
[0017] (ii) a copolymer of ethylene and alkene;
[0018] (iii) a copolymer of ethylene and less than 15 mole percent
of vinyl acetate;
[0019] (iv) a nucleator;
[0020] (v) a wax;
[0021] (vi) a substantially branched alkyl phenol formaldehyde
condensate (known as `APFC`);
[0022] (vii) a comb polymer; and
[0023] (viii) a polar nitrogen compound.
[0024] The jet fuel composition preferably includes jet fuel and an
additive combination of at least one copolymer selected from (i),
(ii) or (iii) and at least one polar nitrogen compound (viii). The
additive combination may also include at least one nucleator
(iv).
[0025] The jet fuel composition preferably includes jet fuel and an
additive combination of at least one copolymer selected from (i),
(ii) or (iii) and at least one comb polymer (vii). The additive
combination may also include at least one nucleator (iv).
[0026] The jet fuel composition preferably includes jet fuel and an
additive combination of at least one polar nitrogen compound (viii)
and at least one comb polymer (vii).
[0027] The jet fuel composition preferably includes jet fuel and an
additive combination of at least one polar nitrogen compound (viii)
and at least one substantially branched alkyl phenol formaldehyde
condensate (vi).
[0028] The jet fuel composition preferably includes jet fuel and an
additive combination of at least one polar nitrogen compound (viii)
and at least one nucleator (iv).
[0029] In accordance with the present invention there is also
provided a process for reducing the pour point of jet fuels, the
process including the following steps:
[0030] a) providing a jet fuel; and
[0031] b) adding at least one of the additives (i) to (viii)
defined above to the jet fuel.
[0032] The inventors have found that the additives mentioned above
are capable of reducing the size and modifying the shape of wax
crystals formed on cooling of jet fuel so that they do not gel and
cause unwanted viscosity increases. The standard pour point test
method ASTM D97 can be used to determine the point at which a fuel
gels. The cold filter plugging point test (`CFPP`) can be used to
determine cold flow operability of fuels (see J. Inst. Pet. vol. 52
(510), June 1966, pp173-285 for details of the test equipment). The
cold filter plugging point test can be modified to a `one-shot`
CFPP test in which a test sample is allowed to cool to the test
temperature and tested only once as the sample is heated up by more
than 10.degree. C. after the one test cycle. The `oneshot` CFPP
test uses a 125 micron mesh rather than the standard 44 micron
mesh.
[0033] The additives should be added to the jet fuel in an amount
ranging from 10 to 20,000 ppm, preferably 100 to 10,000 ppm, and
most preferably from 500 to 5,000 ppm (parts additive per million
parts fuel).
[0034] The jet fuel may be selected from Jet A, Jet A-1, Jet B, MIL
JP 5, MIL JP 7, MIL JP 8 and MIL JP 4. Jet A, Jet A-1 and MIL JP 8
are preferred.
[0035] The additives will now be discussed in more detail
below:
[0036] (i) Copolymers of Ethylene and at Least One Unsaturated
Ester Selected From: Vinyl Esters Having at Least 5 Carbon Atoms,
Alkyl (Meth)Acrylates, Di-alkyl Fumarates and Di-Alkyl
Maleates:
[0037] The vinyl ester preferably has the formula:
--CR.sup.1R.sup.1R.sup.2--CHR.sup.3
[0038] wherein R.sup.2 represents hydrogen or a methyl group;
R.sup.1 represents a --OOCR.sup.4 group wherein R.sup.4 represents
a C.sub.1 to C.sub.28, more preferably a C.sub.1 to C.sub.16, more
preferably a C.sub.1 to C.sub.9, straight or branched chain alkyl
group; R.sup.3 represents hydrogen or alkyl; and the vinyl ester
having at least 5 carbon atoms.
[0039] The vinyl ester is preferably selected from: vinyl
propionate, vinyl butyrate, vinyl hexanoate, vinyl
2-ethylhexanoate, vinyl octanoate and vinyl benzoate. Neo acid
vinyl esters are also useful, such as vinyl neononanoate and vinyl
pivalate.
[0040] The alkyl (meth)acrylate preferably has the formula:
--CR.sup.1R.sup.2--CHR.sup.3--
[0041] wherein R.sup.2 represents hydrogen or a methyl group;
R.sup.1 represents a --COOR.sup.4 group wherein R.sup.4 represents
a C.sub.1 to C.sub.28, more preferably a C.sub.1 to C.sub.16, more
preferably a C.sub.1 to C.sub.9, straight or branched chain alkyl
group; and R.sup.3 represents hydrogen or alkyl.
[0042] The term `(meth)acrylate` is used to include both acrylate
and methacrylate.
[0043] The alkyl (meth)acrylate is preferably selected from:
2-ethylhexyl(meth)acrylate, ethyl (meth)acrylate, n, iso or t-butyl
(meth)acrylate, hexyl (meth)acrylate, isopropyl (meth)acrylate and
lauryl (meth)acrylate.
[0044] The di-alkyl fumarate preferably has the formula: 1
[0045] wherein R.sup.1 and R.sup.2 are independently selected from
alkyl groups having from 1 to 9 carbon atoms, preferably from 1 to
8 carbon atoms.
[0046] The di-alkyl fumarate is preferably selected from: di-ethyl
fumarate, di-butyl fumarate and di(2-ethyl-hexyl) fumarate.
[0047] The di-alkyl maleate preferably has the formula: 2
[0048] wherein R.sup.1 and R.sup.2 are independently selected from
alkyl groups having from 1 to 9 carbon atoms, preferably from 1 to
8 carbon atoms.
[0049] The di-alkyl maleate is preferably selected from: di-ethyl
maleate and di-butyl-maleate.
[0050] Preferably the copolymer has a number average molecular
weight, as measured by Gel Permeation Chromatography using
polystyrene standards, of 1,000 to 20,000, more preferably 1,000 to
10,000, more preferably 2,000 to 5,000.
[0051] If desired, the copolymers may be derived from additional
comonomers, e.g. they may be terpolymers or tetrapolymers or higher
polymers, for example where the additional comonomer is 1-butene,
propene, or diisobutene or another unsaturated ester giving rise to
different units of the above formula.
[0052] Also, the copolymers may additionally include small
proportions of chain transfer agents and/or molecular weight
modifiers (e.g. acetaldehyde or propionaldehyde) that may be used
in the polymerisation process to make the copolymer.
[0053] The copolymers may be made by direct polymerisation of
comonomers. Such copolymers may also be made by
transesterification, or by hydrolysis and re-esterification, of an
ethylene unsaturated ester copolymer to give a different ethylene
unsaturated ester copolymer. For example, ethylene-vinyl hexanoate
and ethylene-vinyl octanoate copolymers may be made in this way,
e.g. from an ethylene vinyl acetate copolymer.
[0054] The copolymers may, for example, have 15 or fewer,
preferably 10 or fewer, more preferably 6 or fewer, most preferably
2 to 5, methyl terminating side branches per 100 polymer backbone
methylene groups, as measured by nuclear magnetic resonance
spectroscopy, other than methyl groups on a comonomer ester and
other than terminal methyl groups.
[0055] The copolymers may have a polydispersity of 1 to 6,
preferably 1.5 to 4; polydispersity being the ratio of weight
average molecular weight to number average molecular weight both as
measured by Gel Permeation Chromatography using polystyrene
standards.
[0056] The copolymer preferably has a molar ethylene content of
between 50 and 95 mol %. Preferably the ethylene content is from 55
to 90 mol %, more preferably 60 to 90 mol %, and most preferably 70
to 90 mol %.
[0057] (ii) Copolymers of Ethylene and Alkene:
[0058] The alkene preferably includes at most 20 carbon atoms. The
alkene is preferably a 1-alkene having at most 20 carbon atoms. The
1-alkene is preferably selected from: propylene, 1-butene,
1-hexene, 1-octene, methyl-1pentene, 1-decene, 1-dodecene,
1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene,
1-octadecene, 1-eicosene and vinyl-cyclohexane, and mixtures
thereof.
[0059] The copolymer may also include small amounts e.g. up to 10%
by weight of other copolymerizable monomers.
[0060] The copolymer may have a molecular weight of 1,000 to
50,000, preferably from 1,000 to 20,000, and most preferably from
1,000 to 10,000, as measured by gel permeation chromatography (GPC)
relative to polystyrene standards.
[0061] The copolymer preferably has a molar ethylene content of
between 50 and 90 mol %. Preferably the ethylene content is from 55
to 85 mol %, more preferably 60 to 85 mol %, and most preferably 70
to 85 mol %.
[0062] The copolymers may be prepared by any of the methods known
in the art, for example, using catalysts selected from:
Ziegler-Natta type catalysts and metallocene catalysts.
[0063] (iii) Copolymers of Ethylene and Less than 15 mol % of Vinyl
Acetate:
[0064] A copolymer of ethylene and vinyl acetate has a
polymethylene backbone divided into segments by hydrocarbyl and
acetate side chains.
[0065] Preferably, the copolymers contain less than 14 mol %, more
preferably less than 12 mol % of vinyl acetate.
[0066] The copolymer preferably has a number average molecular
weight, as measured by gel permeation chromatography (GPC), of
1,000 to 10,000, more preferably 2,000 to 5,000.
[0067] The copolymers may be made by direct polymerisation of
comonomers.
[0068] The copolymers may, for example, have 15 or fewer,
preferably 10 or fewer, methyl terminating side branches per 100
polymer backbone methylene groups, as measured by nuclear magnetic
resonance spectroscopy, other than methyl groups on a comonomer
ester and other than terminal methyl groups.
[0069] The copolymers may have a polydispersity of 1 to 6,
preferably 2 to 4; polydispersity being the ratio of weight average
molecular weight to number average molecular weight both as
measured by Gel Permeation Chromatography using polystyrene
standards.
[0070] (iv) Nucleators:
[0071] The nucleator is preferably a polyoxyalkylene compound.
Examples include polyoxyalkylene esters, ethers, ester/ethers and
mixtures thereof, particularly those containing at least one,
preferably at least two, C.sub.10 to C.sub.30 linear alkyl groups
and one or more polyoxyalkylene glycol group of molecular weight up
to 5,000, preferably 200 to 5,000, the alkylene group in said
polyoxyalkylene glycol containing from 1 to 4 carbon atoms, as
described in EP-A-61 895 and in U.S. Pat. No. 4,491,455.
[0072] Preferred glycols are substantially linear polyethylene
glycols (PEG) and polypropylene glycols (PPG) having a molecular
weight of about 100 to 5,000, preferably about 200 to 1,500. Esters
are also preferred and fatty acids containing from 10 to 30 carbon
atoms are useful for reacting with the glycols to form the ester
additives, it being preferred to use C.sub.12 to C.sub.18 fatty
acid, especially myristic, palmitic and stearic acids. The esters
may also be prepared by esterifying polyethoxylated fatty acids,
polyethoxylated alcohols or polyols.
[0073] Polyoxyalkylene diesters, diethers, ether/esters and
mixtures thereof are suitable as additives, when minor amounts of
monoethers and monoesters (which are often formed in the
manufacturing process) may also be present. In particular,
myristic, palmitic or stearic diesters of polyethylene glycol,
polypropylene glycol or polyethylene/polypropylene glycol mixtures
are preferred.
[0074] Examples of other compounds in this general category are
those described in Japanese Patent Publication Nos. 2-51477 and
3-34790, and EP-A-117,108 and EP-A-326,356, and cyclic esterified
ethoxylates such as described EP-A356,256.
[0075] Other suitable esters are those obtainable by the reaction
of:
[0076] (i) an aliphatic monocarboxylic acid having 10 to 30 carbon
atoms, and
[0077] (ii) an alkoxylated aliphatic monohydric alcohol, in which
the alcohol has greater than 12 carbon atoms prior to alkoxylation
and in which the degree of alkoxylation is 3 to 25 moles of
alkylene oxide per mole of alcohol.
[0078] The ester may be formed from a single acid reactant (i) and
single alcohol reactant (ii), or from mixtures of acids (i) or
alcohols (ii) or both. In the latter cases, a mixture of ester
products will be formed which may be used without separation if
desired, or separated to give discrete products before use.
[0079] These materials may also be prepared by alkoxylation of a
fatty acid ester of a polyol (e.g. ethoxylated sorbitan tristearate
having the trade name TWEEN 65, which is available from Uniqema,
owned by ICI).
[0080] The degree of alkoxylation of the aliphatic monohydric
alcohol is preferably 3 to 25 moles of alkylene oxide per mole of
alcohol, more preferably 3 to 10 moles. The alkoxylation is
preferably ethoxylation, although propoxylation or butoxylation can
also be used successfully. Mixed alkoxylation, for example a
mixture of ethylene and propylene oxide units, may also be
used.
[0081] The acid reactant (i) preferably has 12 to 30 carbon atoms,
more preferably 12 to 18 carbon atoms such as 14 or 16 carbon
atoms. The acid is preferably a saturated aliphatic acid, more
preferably an alkanoic acid. Alkanoic acids of 12 to 30 carbon
atoms are particularly useful. n-Alkanoic acids are preferred. Such
acids include myristic acid, palmitic acid and stearic acid, with
myristic and palmitic acids being preferred. Where mixtures of
acids are used, it is preferred that the average number of carbon
atoms in the acid mixture lies in the above-specified ranges and
preferably the individual acids within the mixture will not differ
by more than 8 (and more preferably 4) carbon numbers.
[0082] The alcohol reactant (ii) is preferably derived from an
aliphatic monohydric alcohol having no more than 28 carbon atoms,
and more preferably no more than 18 (or better, 16) carbon atoms,
prior to alkoxylation. The range of 12 to 18 is particularly
advantageous for obtaining good wax crystal modification. The
aliphatic alcohol is preferably a saturated aliphatic alcohol,
especially an alkanol (i.e. alkyl alcohol).
[0083] Where the alcohol reactant (ii) is a mixture of alcohols,
this mixture may comprise a single aliphatic alcohol alkoxylated to
varying degrees, or a mixture of aliphatic alcohols alkoxylated to
either the same or varying degrees. Where a mixture of aliphatic
alcohols is used, the average carbon number prior to alkoxylation
should be above 12 and preferably within the preferred ranges
recited above. Preferably, the individual alcohols in the mixture
should not differ by more than 4 carbon atoms.
[0084] The esterification can be conducted by normal techniques
known in the art.
[0085] The alkoxylation of the aliphatic alcohol is also conducted
by well-known techniques.
[0086] The nucleator may also be a block copolymer comprising a
single crystallizable block and a single non-crystallizable block
(a `di-block` polymer) and those comprising a a single
non-crystallizable block having at each end a single crystallizable
block (a `tri-block` polymer). Other tri- and tetra-block
copolymers are also available. In preferred embodiments, in which
the copolymer is derived from butadiene and isoprene, these di- and
tri-block polymers are referred to as PE-PEP and PE-PEP-PE
respectively
[0087] The crystallizable 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 blocks
will be the hydrogenation product of the unit resulting from
1,2-polymerization of butadiene (PE-PEB) or from 1,4-polymerization
of an alkyl-substituted butadiene, for example isoprene
(PE-PEP).
[0088] (v) Waxes:
[0089] The waxes may include both normal and non-normal paraffin
hydrocarbons.
[0090] The normal paraffin hydrocarbons preferably range from
C.sub.8H.sub.18 to C.sub.35H.sub.72. Preferably the number average
molecular weight of the paraffin hydrocarbon is in the range of
about 150 to 300. While it is possible to use individual paraffin
hydrocarbons, better results are usually obtained with a paraffin
hydrocarbon comprising a mixture of hydrocarbons. Preferably the
normal hydrocarbons range from C.sub.8 to C.sub.30, preferably
C.sub.10 to C.sub.25.
[0091] The paraffin hydrocarbon may be selected from crude waxes
such as slack wax and slop wax. The paraffin hydrocarbon may be
obtained by conventional dewaxing of various paraffinic petroleum
refinery streams boiling within the range of about 200.degree. C.
to about 500.degree. C. Particularly suitable waxes are slack waxes
obtained from solvent dewaxing of oils having a boiling range of
from about 200.degree. C. to 400.degree. C.
[0092] The non-normal paraffin hydrocarbons preferably include
amorphous solid materials having melting points within the range of
10 to 60.degree. C., preferably 20 to 40.degree. C., and having
number average molecular weights within the range of 150 to
500.
[0093] A suitable amorphous hydrocarbon fraction can be obtained by
`de-oiling` or `sweating` of waxes in the wax refining process.
Non-normal alkane waxes are also known as foots oils and
filtrates.
[0094] (vi) Substantially Branched Alkyl Phenol Formaldehyde
Condensates (`APFC`s):
[0095] Alkyl phenol formaldehyde condensates are disclosed in EP 0
311 452 and EP 0 851 776.
[0096] The alkyl phenol formaldehyde condensate may be obtainable
by the condensation reaction between:
[0097] (i) at least one aldehyde or ketone or reactive equivalent
thereof, and
[0098] (ii) at least one compound comprising one or more aromatic
moieties bearing at least one substituent of the formula --XR.sup.1
and at least one further substituent --R.sup.2, wherein:
[0099] X represents oxygen or sulphur,
[0100] R.sup.1 represents hydrogen or a moiety bearing at least one
hydrocarbyl group, and
[0101] R.sup.2 represents a substantially branched hydrocarbyl
group, preferably containing from 4 to 40 carbons atoms, more
preferably containing from 8 to 30 carbon atoms and most preferably
containing from 8 to 18 carbon atoms.
[0102] Suitable substantially branched alkyl phenol formaldehyde
condensates include iso-nonyl phenol formaldehyde condensates and
iso-dodecyl phenol formaldehyde condensates.
[0103] (vii) Comb Polymers:
[0104] Comb polymers 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).
[0105] Generally, comb polymers consist of molecules in which long
chain branches such as hydrocarbyl branches, optionally interrupted
with one or more oxygen atoms and/or carbonyl groups, having from 6
to 30 such as 10 to 20, carbon atoms, are 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. Generally, comb
polymers are distinguished by having a minimum molar proportion of
units containing such long chain branches.
[0106] As examples of preferred comb polymers there may be
mentioned those containing units of the general formula 3
[0107] where
[0108] D represents R.sup.11, COOR.sup.10, OCOR.sup.10,
R.sup.11COOR.sup.10 or OR.sup.10;
[0109] E represents H or D;
[0110] G represents H or D;
[0111] J represents H, R.sup.11, R.sup.11COOR.sup.10, or a
substituted or unsubstituted aryl or heterocyclic group;
[0112] K represents H, COOR.sup.11, OCOR.sup.11, OR.sup.11 or
COOH;
[0113] L represents H, R.sup.11, COOR.sup.11, OCOR.sup.11 or
substituted or unsubstituted aryl;
[0114] R.sup.10 representing a hydrocarbyl group having 10 or more
carbon atoms, and
[0115] R.sup.11 representing a hydrocarbylene (divalent) group in
the R.sup.11COOR.sup.10 moiety and otherwise a hydrocarbyl
(monovalent) group, and m and n represent mole ratios, their sum
being 1 and m being finite and being up to and including 1 and n
being from zero to less than 1, preferably m being within the range
of from 1.0 to 0.4 and n being in the range of from 0 to 0.6.
R.sup.10 advantageously represents a hydrocarbyl group with from 10
to 30 carbon atoms, preferably 10 to 24, more preferably 10 to 18.
Preferably, R.sup.10 is a linear or slightly branched alkyl group
and R.sup.11 advantageously represents a hydrocarbyl group with
from 1 to 30 carbon atoms when monovalent, preferably with 6 or
greater, more preferably 10 or greater, preferably up to 24, more
preferably up to 18 carbon atoms. Preferably, R.sup.11, when
monovalent, is a linear or slightly branched alkyl group. When
R.sup.11 is divalent, it is preferably a methylene or ethylene
group. By "slightly branched" is meant having a single methyl
branch.
[0116] The comb polymer may contain units derived from other
monomers if desired or required, examples being CO, vinyl acetate
and ethylene. It is within the scope of the invention to include
two or more different comb copolymers.
[0117] The comb polymers may, for example, be copolymers of maleic
anhydride acid and another ethylenically unsaturated monomer, e.g.
an .alpha.-olefin or an unsaturated ester, for example, vinyl
acetate as described in EP-A-214,786. 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, 1-octadecene, and styrene. Other examples of comb
polymers include polyalkyl(meth)acrylates.
[0118] The copolymer 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 that 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, 2-methylpentadecan-1-ol, 2-methyltridecan-1-ol as
described in EP-A-213,879. The alcohol may be a mixture of normal
and single methyl branched alcohols. It is preferred to use pure
alcohols rather than alcohol mixtures such as may be commercially
available; if mixtures are used, the number of carbon atoms in the
alkyl group is taken to be the average number of carbon atoms in
the alkyl groups of the alcohol mixture; if alcohols that contain a
branch at the 1 or 2 positions are used, the number of carbon atoms
in the alkyl group is taken to be the number in the straight chain
backbone segment of the alkyl group of the alcohol.
[0119] The copolymer may also be reacted with a primary and/or
secondary amine, for example, a mono- or di-hydrogenated tallow
amine.
[0120] The comb polymers may especially be fumarate or itaconate
polymers and copolymers such as for example those described in
European Patent Applications 153 176,153 177, 156 577 and 225 688,
and WO 91/16407. The comb polymers are preferably C.sub.8 to
C.sub.12 dialkylfumarate-vinyl acetate copolymers.
[0121] 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 as
described in EP-A-282,342; mixtures of two or more comb polymers
may be used in accordance with the invention and, as indicated
above, such use may be advantageous.
[0122] Other examples of comb polymers are hydrocarbon polymers
such as copolymers of at least one short chain 1-alkene and at
least one long chain 1-alkene. The short chain 1-alkene is
preferably a C.sub.3-C.sub.8 1-alkene, more preferably a
C.sub.4-C.sub.6 1-alkene. The long chain 1-alkene preferably
includes greater than 8 carbon atoms and at most 20 carbon atoms.
The long chain 1-alkene is preferably a C.sub.10-C.sub.14 1-alkene,
including 1-decene, 1-dodecene and 1-tetradecene (see, for example,
WO 93/19106). The comb polymer is preferably a copolymer of at
least one 1-dodecene and at least one 1-butene in the ratio of
60-90 mole % 1-dodecene to 40-10 mole % 1-butene, preferably in the
ratio of 75-85 mole % 1-dodecene to 25-15 mole % 1-butene.
Preferably, the comb polymer is a mixture of two or more comb
polymers made from a mixture of two or more 1-alkenes. Preferably,
the number average molecular weight measured by Gel Permeation
Chromatography against polystyrene standards of such a copolymer
is, for example, up to 20,000 or up to 40,000, preferably from
4,000 to 10,000, preferably 4,000 to 6,000. The hydrocarbon
copolymers may be prepared by methods known in the art, for example
using a Ziegler-Natta type, Lewis acid or metallocene catalyst.
[0123] (viii) Polar Nitrogen Compounds:
[0124] Polar nitrogen compounds are also known as Wax Anti-Settling
Additives (`WASA`).
[0125] Polar nitrogen compounds include an oil-soluble polar
nitrogen compound carrying one or more, preferably two or more,
hydrocarbyl substituted amino or imino substituents, the
hydrocarbyl group being monovalent and containing 8 to 40 carbon
atoms, and the substituents optionally being in the form of a
cation derived therefrom. The oil-soluble polar nitrogen compound
is either ionic or non-ionic and is capable of acting as a wax
crystal growth modifier in fuel oils. Preferably, the hydrocarbyl
group is linear or slightly linear, i.e. it may have one short
length (1-4 carbon atoms) hydrocarbyl branch. When the substituent
is amino, it may carry more than one said hydrocarbyl group, which
may be the same or different.
[0126] The term "hydrocarbyl" refers to a group having a carbon
atom directly attached to the rest of the molecule and having a
hydrocarbon or predominantly hydrocarbon character. Examples
include hydrocarbon groups, including aliphatic (e.g. alkyl or
alkenyl), alicyclic (e.g. cycloalkyl or cycloalkenyl), aromatic,
alicyclic-substituted aromatic, aromatic-substituted aliphatic and
alicyclic groups. Aliphatic groups are advantageously saturated.
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.
[0127] 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.
[0128] More especially, the or each amino or imino substituent is
bonded to a moiety via an intermediate linking group such as
--CO--, --CO.sub.2.sup.(-), --SO.sub.3.sup.(-) or hydrocarbylene.
Where the linking group is anionic, the substituent is part of a
cationic group, as in an amine salt group. If the linking group is
a carbonyl, the substituent part is either an imide or amide
group.
[0129] When the polar nitrogen compound carries more than one amino
or imino substituent, the linking groups for each substituent may
be the same or different.
[0130] Suitable amino substituents are long chain
C.sub.12-C.sub.24, preferably C.sub.12-C.sub.18, alkyl primary,
secondary, tertiary or quaternary amino substituents.
[0131] Preferably, the amino substituent is a dialkylamino
substituent, which, as indicated above, may be in the form of an
amine salt thereof, an amide thereof, or both; tertiary and
quaternary amines can form only amine salts. Said alkyl groups may
be the same or different.
[0132] Preferably the amino substituents include dodecylamino,
tetradecylamino, cocoamino, and hydrogenated tallow amino. Examples
of secondary amino substituents include dioctadecylamino and
methylbehenylamino. Mixtures of amino substituents may be present
such as those derived from naturally occurring amines. A preferred
amino substituent is the secondary hydrogenated tallow amino or
dicocoamine substituent, the alkyl groups of which are derived from
hydrogenated tallow fat and are typically composed of approximately
4% C.sub.14, 31% C.sub.16 and 59% C.sub.18 n-alkyl groups by
weight.
[0133] Suitable imino substituents are long chain
C.sub.12-C.sub.40, preferably C.sub.12-C.sub.24, alkyl
substituents.
[0134] The moiety may be monomeric (cyclic or non-cyclic) or
polymeric. When non-cyclic, it may be obtained from a cyclic
precursor such as an anhydride or a spirobislactone.
[0135] The cyclic ring system may include homocyclic, heterocyclic,
or fused polycyclic assemblies, or a system where two or more such
cyclic assemblies are joined to one another and in which the cyclic
assemblies may be the same or different. Where there are two or
more such cyclic assemblies, the substituents may be on the same or
different assemblies, preferably on the same assembly. Preferably,
the or each cyclic assembly is aromatic, more preferably a benzene
ring. Most preferably, the cyclic ring system is a single benzene
ring when it is preferred that the substituents are in the ortho or
meta positions, which benzene ring may be optionally further
substituted.
[0136] The ring atoms in the cyclic assembly or assemblies are
preferably carbon atoms but may for example include one or more
ring N, S or O atom, in which case or cases the compound is a
heterocyclic compound.
[0137] Examples of such polycyclic assemblies include polycyclic
aromatics, rings joined "end-on" such as diphenyl, heterocylics or
alicyclics.
[0138] Examples of polar nitrogen compounds are described
below.
[0139] (i) an amine salt and/or amide of a mono- or poly-carboxylic
acid, e.g. having 1 to 4 carboxylic acid groups. It may be made,
for example, by reacting at least one molar proportion of a
hydrocarbyl substituted amine with a molar proportion of the acid
or its anhydride.
[0140] When an amide is formed, the linking group is --CO--, and
when an amine salt is formed, the linking group is
--CO.sub.2.sup.(-).
[0141] The moiety may be cyclic or non-cyclic. Examples of cyclic
moieties are those where the acid is cyclohexane 1,2-dicarboxylic
acid; cyclohexene 1,2dicarboxylic acid; cyclopentane
1,2-dicarboxylic acid; and naphthalene dicarboxylic acid.
Generally, such acids have 5 to 13 carbon atoms in the cyclic
moiety. Preferred such cyclic acids are benzene dicarboxylic acids
such as phthalic acid, isophthalic acid, and terephthalic acid, and
benzene tetracarboxylic acids such as pyromelletic acid, phthalic
acid being particularly preferred. U.S. Pat. No. 4,211,534 and
EP-A-272,889 describes polar nitrogen compounds containing such
moieties.
[0142] Examples of non-cyclic moieties are those when the acid is a
long chain alkyl or alkylene substituted dicarboxylic acid such as
a succinic acid, as described in U.S. Pat. No. 4,147,520 for
example.
[0143] Other examples of non-cyclic moieties are those where the
acid is a nitrogen-containing acid such as ethylene diamine
tetracetic acid and nitrilotriacetic acid.
[0144] Further examples are the moieties obtained where a dialkyl
spirobislactone is reacted with an amine as described in
DE-A-392699.
[0145] (ii) A compound having the formula I, or a salt thereof:
4
[0146] wherein B represents an aromatic system, A represents a
hydrocarbyl group, R.sup.1 and R.sup.2 are the same or are
different and each independently is an aliphatic hydrocarbyl group
containing 12-24 carbon atoms, z is at least 1 and wherein the
aromatic system carries at least one substituent group which is an
activating group for the ring system or a derivative of an
activating group.
[0147] By the term hydrocarbyl in this specification is meant an
organic moiety that is composed of hydrogen and carbon, which is
bonded to the rest of the molecule by a carbon atom or atoms and
which, unless the context states otherwise, may be aliphatic,
including alicyclic, aromatic or a combination thereof. It may be
substituted or unsubstituted, alkyl, aryl or alkaryl and may
optionally contain unsaturation or heteroatoms such as O, N or S,
provided that such heteroatoms are insufficient to alter the
essentially hydrocarbyl nature of the group. It is preferred that A
is an aliphatic hydrocarbyl group and more preferably that A is a
methylene group.
[0148] The term aromatic system is meant to include aromatic
homocyclic, heterocyclic or fused polycyclic assemblies, or a
system where two or more such cyclic assemblies are joined to one
another and in which the cyclic assemblies may be the same or
different. Where there are two or more cyclic assemblies and Z is 2
or more the -(A-NR.sup.1R.sup.2) groups present may be in the same
or different assemblies. It is preferred that the aromatic system
is a ring system based on benzene rings.
[0149] The ring atoms in the aromatic system are preferably carbon
atoms but may, for example, include one or more heteroatoms such as
N, S, or O in the system in which case the compound is a
heterocyclic compound.
[0150] Examples of such polycyclic assemblies include
[0151] (a) condensed benzene structures such as naphthalene;
[0152] (b) condensed ring structures where none of or not all of
the rings are benzene such as indene;
[0153] (c) rings joined "end-on" such as diphenyl;
[0154] (d) heterocyclic compounds such as quinoline; and
[0155] (e) bisaromatic systems wherein the rings are linked by one
or more divalent groups such as for example bisphenol A.
[0156] By the term activating group is meant any group, other than
a substituent aliphatic hydrocarbyl group which activates the
aromatic system to substitution reactions such as electrophilic
substitution, nucleophilic substitution or to the Mannich reaction.
The activating group may be a non-substituent group such as
functionality that is within the aromatic system as in, for
example, heterocyclic compounds such as indole. The activating
group is located at least within or on each of the rings of the
aromatic system which are substituted with an -(A-NR.sup.1R.sup.2)
group. It is preferred that the activating group is a group that is
on the ring system as opposed to being within the aromatic system.
Desirably the activating group or groups activate the aromatic
system to electrophilic substitution or to the Mannich reaction,
most preferably to the Mannich reaction. It is preferred that the
activating group activates the aromatic system in the ortho or para
position relative to itself. The preferred activating group is a
hydroxyl group. The preferred activated aromatic system is a
hydroxy aromatic system. By the term derivative of an activating
group is meant any group that can be produced by the reaction of
the activating group. For example, when the activating group is a
hydroxyl group one derivative would be an --O--C(O)--CH.sub.3 group
produced by reaction of the hydroxyl group with, for example,
acetic anhydride. There may be more than one activating group or a
derivative of an activating group on or in the aromatic system;
they may be in or on the same or different rings. There may also be
other substituents present that are in or on the aromatic system
and are not activating groups or derivatives of activating
groups.
[0157] Each aliphatic hydrocarbyl group constituting R.sup.1 and
R.sup.2 in the invention may, for example, be an alkyl or alkylene
group or a mono or polyalkoxyalkyl group or aliphatic hydrocarbyl
group that contains heteroatoms such as O, N or S. Preferably each
aliphatic hydrocarbyl group is a straight chain alkyl group. The
number of carbon atoms in each aliphatic hydrocarbyl group is
preferably 12-24, most preferably 12 to 18.
[0158] Preferably, such as when z=1, the aromatic system also
carries a substituent of general formula II 5
[0159] wherein W=0 or 1; Q represents A; and R.sup.1 and R.sup.2
have the meaning as given above. It is preferred that W=0 and that
there is only one additional substituent of the above general
formula II. The additional substituent of general formula II may
also be present in the aromatic system when z is 2 or more.
When
[0160] The most preferred compounds of general formula I are those
which may be represented by general formula III 6
[0161] wherein X represents hydrogen, or a hydrocarbyl group, or a
non-hydrocarbyl group, or a group of general formula IV: 7
[0162] wherein Y is a divalent group and wherein a=1, 2, 3 or 4,
b=1, 2, 3 or 4, c=0, 1 or 2, d=0, 1, 2, 3 or 4 and e=0, 1, 2, 3 or
4 and wherein R.sup.3, R.sup.4, R.sup.7 and R.sup.8 are hydrogen or
hydrocarbyl, and wherein R.sup.1 and R.sup.2 are independently
C.sub.8-C.sub.30 aliphatic hydrocarbyl groups. D represents a
hydroxyl group or a derivative of a hydroxyl group. When D is a
derivative of a hydroxyl group it is preferably a
--O--C(O)--CH.sub.3 group. The C.sub.10-C.sub.40 aliphatic
hydrocarbyl groups may be linear or branched chains. It is
preferred that the chains are linear.
[0163] When X is a group other than a group of formula IV
preferably a=1 or 2 and b=1, 2, 3 or 4, most preferably a=1 or 2
and b=1, 2 or 3.
[0164] When X is a group of formula IV and c=0, preferably a=1, 2
or 3, b=1, 2 or 3, d=0, 1, 2 or 3, and e=0, 1, 2 or 3, most
preferably a=1, b=1, d=1 and e=1.
[0165] When X is a group of formula IV and c=1, preferably a=1, 2
or 3, b=1, 2 or 3, d=0,1, 2 or 3 and e=0, 1, 2 or 3, most
preferably a=1 or 2, b=1 or 2, d=0,1 or 2 and e=0, 1 or 2.
[0166] In both formulas III and IV the benzene ring may be part of
a larger ring system such as a fused polycyclic ring system or may
be a heterocyclic ring or an aromatic ring other than benzene.
[0167] When c=1 groups III and IV may also be joined directly, as
in when c=0, in addition to being joined by the divalent group Y.
When c=2 the divalent groups Y may be the same or different.
[0168] Preferably R.sup.3, R.sup.4, R.sup.7 and R.sup.8 are
hydrogen. The aliphatic hydrocarbyl groups R.sup.1 and R.sup.2 may
be the same or different and are preferably independently
C.sub.10-C.sub.40 alkyl groups. Desirably the alkyl groups are
independently C.sub.12-C.sub.24 alkyl groups and most preferably
C.sub.12-C.sub.18 alkyl groups. When there is more than one R.sup.1
or R.sup.2 group present they may be the same or different
aliphatic hydrocarbyl groups. Preferred combinations of alkyl
groups are those wherein R.sup.1/R.sup.2 are either
C.sub.16/C.sub.18, C.sub.12/C.sub.14, C.sub.18/C.sub.18 or
C.sub.12/C.sub.12.
[0169] The aliphatic hydrocarbyl groups may also contain hetero
atoms such as O, N or S. It is preferred that no hetero atoms are
present in the aliphatic hydrocarbyl groups and that the groups are
linear or those which have low levels of branching.
[0170] The divalent group Y may be a substituted or unsubstituted
aliphatic group such as for example methylene,
--C(CH.sub.3).sub.2--, --CH(Ph)--, a group of formula V or similar
groups, 8
[0171] or groups such as --C(O)--, S(O)--, S(O).sub.2--, --O--,
--S--, --C(O)--O-- and --C(O)--O--R.sup.11--O--C(O)-- wherein
R.sub.11 is a hydrocarbyl group as hereinbefore defined. When there
are two divalent groups present i.e. when c=2 they may be the same
or different e.g. the combination of the group of formula V and
--O-- as in fluorescein. The divalent group Y may also be an
aromatic group. The divalent group Y may also contain activated
cyclic rings which have the substituent group -(A-NR.sup.1R.sup.2)
present in the cyclic ring.
[0172] The compounds of general formula III may also be substituted
with one or more groups of general formula II. It is preferred that
when X is a group other than that of formula IV and when b=1 that
at least one group of general formula II is present in the compound
of formula III. The compounds of general formula III may also be
substituted with non-hydrocarbyl groups such as for example
NO.sub.2 or CN groups.
[0173] In the compound of formula I as defined above the activating
group is preferably a hydroxyl group. The hydroxyl-aromatic system
is hereinafter referred to as an activated compound. The compound
is prepared by reacting under Mannich condensation conditions a
formaldehyde or an aldehyde and a secondary amine which comprises
independently C.sub.8-C.sub.30 aliphatic hydrocarbyl groups.
[0174] The reactants may be used in equimolar or substantially
equimolar proportions. The mole ratio of the activated compound to
secondary amine may be less than equimolar for example 1:2, 1:3 or
1:4 or more. It is preferred that the mole ratio of activated
compound to secondary amine is 1:2 or substantially 1:2 and that
there is sufficient formaldehyde present to enable this mole ratio
to be achieved in the final product.
[0175] The reaction may be carried out in a solvent for example
toluene or without a solvent and at a temperature in the range of
80.degree. C. to 120.degree. C.
[0176] The aldehyde may be any aldehyde that reacts with an
activated compound and a C.sub.8-C.sub.30 aliphatic hydrocarbyl
secondary amine under Mannich condensation conditions. It is
preferred that formaldehyde is used in the method. The formaldehyde
may be employed in any of its conventional forms; it may be used in
the form of an aqueous solution such as formalin, as
paraformaldehyde or as trioxane.
[0177] Suitable hydroxyaromatic compounds include for example:
substituted phenols such as 2-, 3-, or 4-hydroxybenzophenone, 2-,
3-, or 4-hydroxybenzoic acid and 1 or 2-naphthol; dihydroxy
compounds such as resorcinol, catechol, hydroquinone,
2,2'-biphenol, 4,4'biphenol, fluorescein, 2,2-bis(p-hydroxy
phenyl)propane, dihydroxybenzophenones, 4,4'thiodiphenol, or
dihydroxy benzoic acids such as 2,4-, or 3,5-dihydroxybenzoic acid;
or trisphenolic compounds such as 1,1,1-tris-(4-hydroxy
phenyl)ethane. The hydroxy aromatic compounds may be substituted,
for example, with one or more of the following substituents:
no-hydrocarbyl groups such as --NO.sub.2 or CN; or hydrocarbyl
groups such as --CHO, --COOR, --COR, --COOR; or aliphatic
hydrocarbyl groups such as alkyl groups. The substituent or
substituents may be in the ortho, para or meta or any combination
of these positions in relation to the hydroxyl group or groups.
When the hydroxyaromatic compound is a substituted phenol it is
preferred that the substitution is in the ortho or para position.
Phenols which have certain para substituents have been found to
produce bisdialkylaminomethyl Mannich reaction products, derived
from secondary amines with aliphatic hydrocarbyl groups of C.sub.8
to C.sub.30, under milder reaction conditions and with greater ease
than when using unsubstituted phenol. In some cases substitution in
the ortho position also allows easier reaction under milder
conditions, though some such substituents are not beneficial, such
as those substituents which are able to hydrogen bond with the
hydroxyl group. A suitable ortho substituent is a cyano group. It
will be understood that with dihydroxy compounds such as catechol
where two or more hydroxy groups are present in the same ring, that
any one substituent may be ortho with respect to one of these
hydroxy groups and meta in relation to the other.
[0178] The amine may be any secondary amine that contains linear
and/or branched chain aliphatic hydrocarbyl groups of
C.sub.8-C.sub.30, and preferably C.sub.10-C.sub.22 and most
preferably C.sub.12-C.sub.18. Preferred secondary amines are linear
or those that have low levels of branching.
[0179] Examples of suitable secondary amines include the simple
secondary amines such as N,N-dodecylamine, N,N-dihexadecylamine,
N,N-dioctadecylamine, N,N-dieicosylamine, N,N-didocosylamine,
N,N-di hydrogenated tallow amine and secondary amines in which the
two alkyl groups are the same or different and selected from the
following functionality: dodecyl, tetradecyl, hexadecyl, octadecyl,
eicosyl, docosyl, cetyl, stearyl, arachidyl, behenyl or
hydrogenated tallow or that derived from the fatty acids of coconut
oil.
[0180] Additional substituents of general formula II may be formed
on the aromatic system during the above reaction by reacting
activated compounds which have a carboxylic acid group present,
with the corresponding amount of amine to take part in the above
reaction and also to neutralise the carboxylic acid groups present.
Alternatively the carboxylic acid groups may be neutralised after
the reaction by adding the required amount of amine, which may be
the same or a different amine to that used in the reaction, to
neutralise the carboxylic acid groups.
[0181] There may be an additional reaction stage to convert the
activating group into a derivative of the activating group such as,
for example, the conversion of a hydroxyl group to its acetate
ester by reaction for example with acetic anhydride.
[0182] (iii) A condensate of a long chain primary or secondary
amine with a carboxylic acid-containing polymer.
[0183] Specific examples include polymers such as described in
GB-A-2,121,807, FR-A-2,592,387 and DE-A-3,941,561; and also esters
of telomer acid and alkanoloamines such as described in U.S. Pat.
No. 4,639,256; and the reaction product of an amine containing a
branched carboxylic acid ester, an epoxide and a mono-carboxylic
acid polyester such as described in U.S. Pat. No. 4,631,071.
[0184] EP 0,283,292 describes amide containing polymers and EP
0,343,981 describes amine-salt containing polymers.
[0185] It should be noted that the polar nitrogen compounds may
contain other functionality such as ester functionality.
[0186] The jet fuel composition may also include at least one of
the following additives: anti-oxidant, metal deactivator, static
dissipater to provide a conductivity of 50 to 450 pS/m, anti-freeze
additive such as ethylene glycol monomethyl ether (EGME), corrosion
inhibitor, biocide, anti-foamant, lubricity additive and
detergent.
[0187] The invention will now be described, by way of example only,
with reference to the following examples:
EXAMPLES
[0188] Tests were conducted using the jet fuels shown in Table 1
below:
1TABLE 1 Jet Fuel Characteristics Jet Fuel Example A Jet Fuel
Example B D 86, IBP 151.3 148.6 5% 162 160.4 10% 166.8 166.0 20%
172.7 173.6 30% 178.5 180.6 40% 185 189.1 50% 191.9 198.7 60% 199.3
209.6 70% 208.2 220.8 80% 219 231.9 90% 233 243.5 95% 245 251.5 FBP
257 258.0 90% - 20% 69.9 FBP - 90% 14.5 Flash Pt C 42 cloud point
-59 pour point avg -57 -54.0 freeze point -54.7 -49 Density 15 deg
C 803.7 807.1 GC n-alkanes C8 0.776 0.7174 C9 2.402 3.6507 C10
4.249 3.2286 C11 3.686 2.8060 C12 2.784 2.2606 C13 2.473 2.2366 C14
1.354 1.8120 C15 0.487 1.1841 C16 0.119 0.1588 C17 0.030 0.0110 C18
0.008 0.0037 C19 0.004 0.0043 C20 0.003 0.0042 C21 0.003 0.0026 C22
0.002 0.0012 C23 0.001 0.0005 C24 0.000 0.0000
[0189] The additives were added to jet fuel example A and the fuel
compositions were tested for pour point using the standard pour
point test method ASTM D97. The results are shown below in Table
2:
2TABLE 2 Pour Point in Jet Fuel Example A Treat Pour Pt, % mole %
mole % Additive (ppm ai) .degree. C. Me VA V2EH Mn None 0 -57 EVP
1000 -60 Comparative EVA 1000 -63 5.6 17.5 3749 Comparative EVA
1000 -60 4.89 18.35 0.0 6835 Comparative EVA 1000 -60 2.07 20.20
0.0 4360 Comparative EV2EH 1000 -84 2.8 0 28.8 5334 EV2EH 1000 -81
3 0 27.4 5948 EVAV2EH 1000 -78 5.96 3.92 10.69 2543 EV2EH 1000 -78
4.97 0.00 17.51 4307 EV2EH 1000 -78 4.01 0.00 16.74 4089 EV2EH 1000
-72 3.73 0.00 16.01 3649 EV2EH 1000 -72 3.03 0.00 16.10 5053 EV2EH
1000 -72 4.06 0.00 14.31 4232 EVAVO 1000 -78 5.2 2.0 -- 2930 EVP -
ethylene-vinyl propionate; EVA - ethylene-vinyl acetate; EV2EH -
ethylene-vinyl-2-ethyl hexanoate; EVAV2EH - ethylene-vinyl
acetate-vinyl-2-ethyl hexanoate; EVAVO - ethylene-vinyl
acetate-vinyl octanoate; Mn was measured using polystyrene
molecular weight standards; % Me - number of methyl terminating
groups (--CH3) per 100 backbone methylene (--CH.sub.2--)
groups.
[0190] As shown in Table 2, the ethylene-vinyl acetate copolymer
having more than 15 mol % of vinyl acetate (comparative example)
only managed to reduce the pour point of jet fuel example A to
-63.degree. C., whereas the ethylene-vinyl-2-ethyl hexanoate,
falling within the invention, reduced the pour point of jet fuel
example A to -84.degree. C.
[0191] The additives were also tested in jet fuel example B, which
has Jet A-1 cold flow freezing characteristics. The results are
shown below:
3TABLE 3 Pour Point in Jet Fuel Example B Treat Pour Pt, mole %
mole % Additive (ppm ai) .degree. C. % Me VA V2EH Mn None 0 -57 EVA
1000 -60 4.60 15 0 3700 comparative EVAV2EH 1000 -75 3 3.5 12
4700
[0192] The ethylene-vinyl acetate having a vinyl acetate content of
15 mol % (comparative example) only reduced the pour point of jet
fuel example B to -60.degree. C., whereas the ethylene-vinyl
acetate-vinyl-2-ethyl hexanoate reduced the pour point of jet fuel
example B to -75.degree. C.
[0193] Combinations of additives were also used to depress the pass
temperature of jet fuel example A in a one-shot `CFPP` test with a
125 micron mesh (standard mesh for CFPP test is a 44 micron mesh).
Details of the cold filter plugging point test equipment can be
found in J. Inst. Pet. vol. 52 (510), June 1966, pp 173-285. The
results are shown below:
4TABLE 4 `One-Shot` CFPP Improvement in Jet Fuel Example A PPM of
PPM of Lowest Improve- Addi- Addi- Pass, ment Additive 1 tive 1
Additive 2 tive 2 .degree. C. .degree. C. None -56 0 EVA, 1000 -58
2 15 mol % VA, comparative EV2EH 200 C.sub.12 WASA 800 -62 6 EV2EH
200 C.sub.12 WASA 800 -62 6 EV2EH 200 C.sub.12 WASA 800 -62 6
EVAV2EH 200 C.sub.12 WASA 800 -62 6 C2/C4 (80/20) 500 C.sub.12 WASA
500 -62 6 C2/C4/C14 500 C.sub.12 WASA 500 -62 6 (82/12/6) C2/C4/C14
500 C.sub.12 WASA 500 -62 6 (80/14/5) C2/C4/C14 500 C.sub.12 WASA
500 -62 6 (81/15/4) C12/C4 500 C.sub.12 WASA 500 -62 6 (23/77)
C10/12 FVA 500 C.sub.12 WASA 500 -62 6 APFC 500 C.sub.12 WASA 500
-62 6 EVA, 500 C.sub.12 WASA 500 -62 6 5.6 mol % VA EVA, 500
C.sub.12 WASA 500 -62 6 11 mol % VA PEG (400) 500 C.sub.12 WASA 500
-62 6 Distearate EVA, 500 C.sub.12 WASA 500 -62 6 14.1 mol % VA
EVA, 500 C.sub.12 WASA 500 -62 6 10.5 mol % VA PEPEB 500 C.sub.12
WASA 500 -62 6 C.sub.12 WASA - dicocoamine/phthalic anhydride
derived wax anti-settling additive; C.sub.2/C.sub.4 -
ethylene/butene copolymer; C.sub.2/C.sub.4/C.sub.14 -
ethylene/butene/tetradecene terpolymer; C.sub.12/C.sub.4 -
dodecene/butene comb polymer; C.sub.10/C.sub.12 FVA -
(di-decyl/dodecyl-fumarate)/vinyl acetate copolymer; APFC -
iso-nonyl phenol formaldehyde condensate; PEG 400 - polyethylene
glycol (400) distearate; PEPEB - polyethylene/polyethylene-butene
block copolymer.
[0194] The additives were also tested for their water separation
characteristics in a further jet fuel using ASTM D 3948-93. The
test measures the ability of aviation fuels to release entrained or
emulsified water when passed through a fiberglass coalescing
material. A micro separometer rating (`MSEP`) is given to indicate
the ease of separating emulsified water from fuel by coalescence.
High ratings indicate that water is easily coalesced, implying that
the fuel is relatively free of surfactant materials, which are
known to block or disarm water filters used in ground-based water
separators. The results are given below:
5TABLE 5 MSEP Rating PPM of Mole % VA in Additive Mole % VO in
Additive Additive in Jet Fuel Additive MSEP EVA 3.5 1000 82 EVA
9.82 1000 99 EVA -10.46 1000 98 EVA 14.08 1000 69 EVA, 15 1000 less
than 50 comparative EVA, 18.02 1000 less than 50 comparative EVA,
20.20 1000 less than 50 comparative EVA, 22.94 1000 less than 50
comparative EVAVO 14.8 1000 3.2 85 EVAVO 7.5 1000 6.3 89 EVAVO 3.3
1000 11.8 89 EV2EH 0.1 1000 5.8 97 EV2EH 0 1000 13.2 96 EV2EH 0
1000 17.5 96 EV2EH 0 1000 27.3 97 EVAV2EH 3.9 1000 10.7 93 EVAV2EH
3.5 1000 12 93 C.sub.2/C.sub.4 alkene 1000 92 (80:20)
C.sub.12/C.sub.4 comb 1000 93 polymer (23:77) C.sub.12/C.sub.4 comb
1000 86 polymer (12:88) C.sub.2/C.sub.4 - ethylene/butene
copolymer; C.sub.12/C.sub.4 comb polymer - dodecene/butene comb
polymer.
[0195] An MSEP rating of less than 50 is considered to be a fail.
Copolymers of ethylene and vinyl acetate including 15 mole percent
or more of vinyl acetate failed the MSEP test. These copolymers
would therefore block or disarm filters in ground-based
water-separators and prevent water removal from jet fuel.
[0196] Table 6 below shows the relationship in jet fuel example A
between the pour point temperature, the precipitation temperature
and the dissolution temperature of a range of additives. Additives
producing a lower pour point have lower precipitation and
dissolution temperatures.
6TABLE 6 Pour Point/Precipitation Temp./Dissolution Temp.
Relationship Precipitate Dissolution Pour point (.degree. C.) of
Jet temp (.degree. C.) temp (.degree. C.) Fuel Example A with for
1000 ppm for 1000 ppm Additive Type 1000 ppm of Additive Additive
Additive None -57 EV2EHVA -81 -44 -37 EV2EH -78 -39 -26 EV2EHVA -72
-36 -18 EV2EH -69 -27 -3 EVA -66 -17 0 (15 mol % VA)
comparative
[0197] The additives were also tested for cloud point depression
(`CPD`) in jet fuel example A. The additives were added to jet fuel
example A and the jet fuel was placed overnight in a cold box at
-53.degree. C. The fuel was then further cooled in one degree steps
per hour. The fuel samples were checked for their visual
appearance. Two measurements were recorded: the first measurement
was the lowest temperature at which the fuel remained clear or had
low haze, and the second measurement was the highest temperature at
which the fuel was observed to have turned cloudy. The results are
shown below in Table 7.
7TABLE 7 Cloud Point Depression in Jet Fuel A Lowest Temperature
Highest Temperature (.degree. C.) Fuel (.degree. C.) at is clear or
has which Fuel Turned Additive Mn low haze Cloudy no additive --
-56 -58 1-dodecene/1-butene 9,800 -61 -63 (77.5/22.5 mole %)
hydrocarbon comb polymer 1-dodecene/1-butene 5,400 -61 -64 (79/21
mole %) hydrocarbon comb polymer 1:1 mixture of 1- -- -64 no
measurement taken dodecene/1-butene (77.5/22.5 mole %) and
1-dodecene/1-butene (79/21 mole %) hydrocarbon comb polymers
* * * * *