U.S. patent application number 10/459775 was filed with the patent office on 2004-12-16 for aviation fuel cold flow additives and compositions.
This patent application is currently assigned to General Electric Company. Invention is credited to Carey, William S., Deng, Fang, Eldin, Sherif, Goliaszewski, Alan E..
Application Number | 20040250465 10/459775 |
Document ID | / |
Family ID | 33510868 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040250465 |
Kind Code |
A1 |
Deng, Fang ; et al. |
December 16, 2004 |
Aviation fuel cold flow additives and compositions
Abstract
Aviation fuel, such as jet fuel, blends and methods for
improving cold flow properties of such fuels at extremely low
temperatures are disclosed. Cold flow properties of, for example,
JP-8 based jet fuels are improved by addition to the fuel of a
variety of C.sub.10-C.sub.16 alkyl poly(meth)acrylate esters and
polyvinylesters of C.sub.10-C.sub.16 alkanoic acids. Demonstratable
cold flow improvement of such fuels at temperatures of about
-53.degree. C. and below is shown.
Inventors: |
Deng, Fang; (Drexel Hill,
PA) ; Carey, William S.; (Wallingford, PA) ;
Eldin, Sherif; (Houston, TX) ; Goliaszewski, Alan
E.; (The Woodlands, TX) |
Correspondence
Address: |
WEGMAN, HESSLER & VANDERBURG
6055 ROCKSIDE WOODS BOULEVARD
SUITE 200
CLEVELAND
OH
44131
US
|
Assignee: |
General Electric Company
Fairfield
CT
|
Family ID: |
33510868 |
Appl. No.: |
10/459775 |
Filed: |
June 12, 2003 |
Current U.S.
Class: |
44/385 |
Current CPC
Class: |
C10L 1/2222 20130101;
C10L 1/2364 20130101; C10L 1/1963 20130101; C10L 1/1881 20130101;
C10L 1/143 20130101; C10L 1/1973 20130101; C10L 1/224 20130101 |
Class at
Publication: |
044/385 |
International
Class: |
C10L 001/18 |
Claims
What is claimed is:
1. Method of improving the cold flow rate of jet fuel comprising
adding to said jet fuel an effective amount for the purpose of a
polymeric cold flow rate enhancement agent (CFREA) having (a)
repeat units characterized by the formula 7wherein R.sub.1 is
hydrogen, CH.sub.3, or mixtures thereof; R.sub.2 is --C(O)--O--,
--O--(O)C--, --C(O)--NH--, or mixtures thereof; R.sub.3 is
C.sub.10-C.sub.16 alkyl, or mixtures thereof, repeat units (b) from
0 to 5 mole percent of a branching agent, and (c) from 0 to 20 mole
percent of a repeat unit resulting from free radical ring-opening
polymerization of a cyclic monomer characterized by the formula
8wherein R.sub.4 is --O--, --S--, --N(CH.sub.3)--, --CH.sub.2-- or
mixtures thereof; and x is an integer from 1 to 3.
2. Method as recited in claim 1 comprising adding from a 1-7,500 mg
of said CFREA to said jet fuel, based upon 1 liter of said jet
fuel.
3. Method as recited in claim 1 wherein said jet fuel is a JP-8
based jet fuel.
4. Method as recited in claim 1 wherein said CFREA is a
C.sub.10-C.sub.16 alkyl poly(meth)acrylate ester.
5. Method as recited in claim 1 wherein said CFREA comprises a
mixture of C.sub.10-C.sub.16 alkyl poly(meth)acrylate esters.
6. Method as recited in claim 1 wherein said CFREA is a
polyvinylester of a C.sub.10-C.sub.16 carboxylic acid.
7. Method as recited in claim 5 wherein said CFREA is
poly(vinyldecanoate).
8. Method as recited in claim 4 wherein said CFREA is
polylauryl(meth)acrylate.
9. Method as recited in claim 4 wherein said CFREA is
polydecylacrylate.
10. Method as recited in claim 4 wherein said CFREA is
polytridecyl(meth)acrylate.
11. Method as recited in claim 1 further comprising adding, as an
adjuvant treatment to said jet fuel about 1-7,500 mg/L of an
oil-soluble, polar nitrogen compound to said jet fuel.
12. Method as recited in claim 11 wherein said oil-soluble, polar
nitrogen compound comprises an amine salt or amide.
13. Method as recited in claim 12 wherein said oil-soluble polar
nitrogen compound comprises a reaction product formed from reaction
of a hydrocarbyl acid having two or more carboxyl groups, or
anhydride thereof, and a hydrocarbyl secondary amine followed by
neutralization of the resulting product with a hydrocarbyl primary
amine.
14. Method as recited in claim 11 wherein said oil-soluble, polar
nitrogen compound is benzoic acid, 2-[(bis(hydrogenated tallow
alkyl)amino)carbonyl]-C.sub.16-C.sub.22 tert-alkyl amine salt.
15. Composition for improving the cold flow rate of jet fuel said
composition comprising, in an organic solvent medium, 1) a
polymeric cold flow rate enhancement agent (CFREA) having (a)
repeat units characterized by the formula 9wherein R.sub.1 is
hydrogen, CH.sub.3, or mixtures thereof; R.sub.2 is --C(O)--O--,
--O--(O)C--, --C(O)--NH--, or mixtures thereof; R.sub.3 is
C.sub.10-C.sub.16 alkyl, or mixtures thereof, repeat units (b) from
0 to 5 mole percent of a branching agent, and repeat units (c)
having from 0 to 20 mole percent of a repeat unit resulting from
free radical ring-opening polymerzation of a cyclic monomer
characterized by the formula 10wherein R.sub.4 is --O--, --S--,
--N(CH.sub.3)--, --CH.sub.2-- or mixtures thereof; and x is an
integer from 1 to 3; and 2) an oil-soluble, polar,
nitrogen-containing compound.
16. Composition as recited in claim 15 wherein 1) is present in an
amount of about 0.01-100 moles of 1) per one mole of 2).
17. Composition as recited in claim 15 wherein said oil-soluble
polar nitrogen-containing compound is an amine salt and/or
amide.
18. Composition as recited in claim 17 wherein said oil-soluble,
polar nitrogen-containing compound is a reaction product formed by
reaction of a C.sub.4-C.sub.24 hydrocarbyl acid or anhydride
thereof with a C.sub.4-C.sub.24 hydrocarbyl substituted primary,
secondary, and/or tertiary amine.
19. Composition as recited in claim 18 wherein said oil-soluble,
polar nitrogen containing compound comprises a reaction product
formed from reaction of a hydrocarbyl acid having two or more
carboxyl groups or an anhydride thereof and a hydrocarbyl secondary
amine followed by neutralization of the resulting product with a
hydrocarbyl primary amine.
20. Compositions as recited in claim 15 wherein said oil-soluble,
polar nitrogen compound is benzoic acid 2-[(bis(hydrogenated tallow
alkyl) amino)carbonyl]C.sub.16-C.sub.22 tert-alkyl amine salt.
21. Composition as recited in claim 19 wherein said CFREA is
polylauryl(meth)acrylate.
22. Composition as recited in claim 20 wherein said CFREA is
polylauryl(meth)acrylate.
Description
FIELD OF THE INVENTION
[0001] The invention pertains to jet fuel blends and methods in
which a cold flow enhancement agent is added to the jet fuel to
improve fuel flow rates and flow characteristics at low fuel
temperatures.
BACKGROUND OF THE INVENTION
[0002] It is important that aviation fuel exhibit a freeze point
that is sufficiently low to allow adequate fuel flow through fuel
system lines and filters to the engine. It is known that fuel
temperature decreases as flight time increases and that longer
duration flights typically require lower freezing point fuels than
do shorter duration flights.
[0003] Additionally, high altitude flights, such as those conducted
under some military operational conditions, also require lower
freezing point fuels than do lower altitude conventional flights.
Quite obviously then, there is a need to provide freeze point
depressant/cold flow enhancement aids for aviation fuels,
particularly for jet fuels, which will allow for sufficient fuel
flow to desired combustion locations at the extremely low fuel
temperatures encountered at high altitude and long duration
flights. Publications WO 01/32811 A1 and WO 01/62874 A2 discuss
details of aviation fuels and the need for lowered freeze point
fuel blends.
[0004] One such means of enhancing the cold flow properties of wax
containing hydrocarbon fluids is via chemical treatment. For
example, use of poly[(meth)acrylates] as a pour point depressant
for hydrocarbon lubricating oil is taught by U.S. Pat. Nos.
5,312,884 and 5,368,761.
[0005] WO 01/62874 A2 teaches the use of various chemical
additives, including certain copolymers of vinyl acetate and
ethylene, to lower the freeze point of aviation fuels. It is
further taught that certain classes of pour point additives known
to those skilled in the art for treating middle distillates, such
as heating oils and diesel fuels, are not necessarily effective in
the treatment of aviation fuel and actually may be detrimental.
[0006] U.S. Pat. No. 6,265,360 B1 teaches the use of
transesterified acrylate polymer to improve the cold flow
properties of wax-containing liquid hydrocarbons. It is speculated
in the teaching that the additive can be prepared from a
methacrylate and is effective in treating jet fuel. However, the
untreated pour point of the responsive fluids was limited to
-40.degree. F. in the teaching and ranged from 75.degree.
F.-95.degree. F. in the examples.
SUMMARY OF THE INVENTION
[0007] Methods for improving the cold flow rate of aviation fuels,
and jet fuels in particular, are provided wherein the jet fuel is
blended with a cold flow rate enhancement agent (CFREA). The CFREA
is a polymer having a majority of repeat units as follows: 1
[0008] wherein R.sub.1 is hydrogen, CH.sub.3, or mixtures thereof;
R.sub.2 is --C(O)--O--, --O--(O)C--, --C(O)--NH--, or mixtures
thereof; and R.sub.3 is chosen from straight and branched
C.sub.10-C.sub.16 alkyl groups. Preferably, the CFREA is a
poly[C.sub.10-C.sub.16 alkyl methacrylate] or a poly[vinylester] of
a C.sub.10-C.sub.16 alkanoic acid.
[0009] The invention will be further described in conjunction with
the attached drawings and following detailed description.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIGS. 1 and 2 are graphs showing viscosity of certain test
jet fuel/CFREA blends compared to a control sample.
DETAILED DESCRIPTION
[0011] In accordance with the present invention, it has been
discovered that polymers having the repeat unit (a) as defined
below are effective in depressing (lowering) the pour point of
aviation fuel. Repeat unit (a) has the structure: 2
[0012] wherein R.sub.1 is hydrogen, CH.sub.3, or mixtures thereof;
R.sub.2 is --C(O)--O--, --O--(O)C--, --C(O)--NH--, or mixtures
thereof; and R.sub.3 is C.sub.10-C.sub.16 alkyl, or mixtures
thereof and the like. Preferably, R.sub.1 is CH.sub.3; R.sub.2 is
--C(O)--O--; and R.sub.3 is C.sub.10-12 alkyl, mixtures thereof,
and the like. Most preferably, R.sub.1 is CH.sub.3, R.sub.2 is
--C(O)--O--, and R.sub.3 is C.sub.12 alkyl.
[0013] As used herein, C.sub.10-C.sub.16 alkyl means any
predominantly straight chain alkyl group having 10 to 16 carbon
atoms per group. Most preferably, the alkyl groups consist of at
least 90-mole % straight chain alkyl groups having 10 to 16 carbon
atoms per group.
[0014] Exemplary monomers encompassed by the repeat unit (a)
include, but are not limited to, alkyl methacrylates such as
dodecyl methacrylate, lauryl methacrylate, tridecyl methacrylate,
tertradecyl methacrylate, and hexadecyl methacrylate; alkyl
acrylates such as dodecyl acrylate, lauryl acrylate, tridecyl
acrylate, tertradecyl acrylate, and hexadecyl acrylate;
N-alkylacrylamide such as N-dodecylacrylamide, N-laurylacrylamide,
N-hexadecylacrylamide; N,N-dialkylacrylamide such as
N,N-didodecylacrylamide; N-alkylmethacrylamide such as
N-dodecylmethacrylamide, N-laurylmethacrylamide,
N-hexadecyl-methacrylami- de; alkyl vinyl esters such as vinyl
decanoate and vinyl dodecanoate; and mixtures of any of the
foregoing and the like.
[0015] The polymers of the present invention may be prepared via
methods known to those skilled in the art, for example, see Allcock
and Lampe, Contemporary Polymer Chemistry, (Englewood Cliffs, N.J.,
PRENTICE-HALL, 1981, chapters 3-5), and U.S. Pat. Nos. 5,312,884
and 5,368,761. Preferably, the polymerization is conducted in a
hydrocarbon solvent employing an oil-soluble free radical
initiator. The solvent may be any inert hydrocarbon and is
preferably hydrocarbon oil such as Aromatic 100 (Exxon), HAN (Heavy
Aromatic Naphtha (Exxon), or toluene that is compatible with the
aviation fuel in which the polymer additive is to be subsequently
used. Preferred classes of oil-soluble free radical initiators
include, but are not limited to, the peroxides such as lauroyl
peroxide and benzoyl peroxide, and azo compounds such as AIBN
(2,2'-azobisisobutyronitrile).
[0016] Any of the conventional chain transfer agents known to those
skilled in the art may be used to control the molecular weight.
These include, but are not limited to, lower alkyl alcohols such as
isopropanol, amines, mercaptans such as n-dodecyl mercaptan and
t-dodecyl mercaptan, phosphites such as diethyl phosphite,
thiaocids, allyl alcohol, and the like.
[0017] Branching agents known to those skilled in the art may also
be used. These branching agents in this case are those compounds
having two or more free radical polymerizable groups that can be
either dissolved or dispersed in hydrocarbon solvent such as
Aromatic 100 (Exxon), HAN (Heavy Aromatic Naptha), (Exxon) or
toluene that is compatible with the aviation fuel in which the
polymer additive is to be subsequently used. Examples of such
branching agents include, but are not limited to,
methylenebisacrylamide, 1,4-butanediol dimethacrylate, diallylurea,
trimethylol propane trimethacrylate, polyethyleneglycol diacrylate,
and the like and may form an optional repeat unit (b). The level of
branching agent (repeatable unit (b)) utilized is limited to that
which yields oil-soluble or oil-dispersible polymers. More
preferably the amount of these branching agents, when used, ranges
from about 10 ppm to about 5 mole % of the total monomer
charge.
[0018] It is also known to those skilled in the art that the
backbone of the polymers compositions of the present invention
comprising the repeat unit (a) can optionally be modified to add
functionality to vary their thermal stability. For example, the
free radical polymerization can be conducted in the presence of
from about 10 ppm to about 20 mole % of 2-methylene-1,3-dioxepane
to insert ester linkages into the backbone of the polymer
matrix.
[0019] Thus, an optional repeat unit (c) may also be present in an
amount from 0-20 mole %. These repeat units (c) result from free
radical ring opening polymerization of a cyclic monomer having the
formula: 3
[0020] wherein R.sub.4 is --O--, --S--, --N(CH.sub.3)--,
--CH.sub.2-- or mixtures thereof; and x is an integer from about 1
to about 3. Cyclic monomers included within this formula are known
to undergo thermally initiated radical ring opening polymerization.
For example, ring opening of 2-methylene-1,3-dioxepane will result
in the incorporation of ester functionality in the polymer backbone
according to the following: 4
[0021] Accordingly, the polymer may comprise repeat units (a), (b),
and (c) wherein (b) when present, is present in an amount of about
10 ppm-5 mole % and (c) when present, is present in an amount of 10
ppm to about 20 mole %, repeat unit (a) is present in a molar
amount of 100% minus (molar amount of (b) and (c))=molar amount
(a).
[0022] Alternatively, the polymers of the present invention can be
produced by transesterification of a poly[alkyl(meth)acrylate] by
methods known to those skilled in the art, for example, see U.S.
Pat. No. 6,265,360 B1. The starting poly[alkyl(meth)acrylate] is
typically a hydrocarbyl acrylate polymer containing from 1 to 10
carbon atoms. Preferably, the starting poly[alkyl(meth)acrylate]
would be prepared from a (meth)acrylate monomer with relative low
cost such as methyl acrylate or methyl methacrylate. The alkyl
groups are selected primarily with respect to the boiling point of
the corresponding alcohols that are removed from the reaction
mixture in the course of the transesterification reaction.
[0023] Generally, as the number of carbon atoms increases, the
removal of the alcohols creates greater difficulties. The alcohols
used for transesterifying of the starting poly[alkyl(meth)acrylate]
include monohydric alcohols represented by the formula ROH, wherein
R is a hydrocarbyl group of about 10 to about 30 carbon atoms.
Although both primary and secondary alcohols can be used of the
transesterification reaction, primary alcohols are preferred. Most
preferred are primary alcohols having a linear hydrocarbyl
structure. The transesterification reaction may be carried out in
the presence of known transesterification catalysts. These include
acids, bases, and lipase enzymes. The acids include mineral acids,
sulfonic acids, as well as mixtures of these. The bases include
alkali metal oxides, hydroxides, or alkoxides. The lipase enzymes
include, but are not limited to, porcine pancreas lipase (PPL) and
Novozyme 435. The transesterification reaction can be conducted in
the present of high boiling aromatic or paraffinic solvents.
[0024] As would be understood by one skilled in the art in view of
the present disclosure, it is intended that the aforementioned
polymerization methods do not in any way limit the synthesis of the
polymer of the present invention. Furthermore, it is to be
understood that polymers comprising two or more different members
from the repeat unit (a) group are also within the purview of the
present invention. Preferred CFREA polymers in accordance with the
above are the poly[C.sub.10-C.sub.16 alkyl(meth)acrylates] and/or
polyvinyl esters of C.sub.10-C.sub.16 alkanoic acids.
[0025] The polymers of the present inventions should be added to an
aviation fuel, for which improved cold flow performance is desired,
in an amount effective for the purpose. In the preferred embodiment
of the invention, the aviation fuel is selected from Jet Fuel A,
Jet Fuel A-1, Jet Fuel B, JP-4, JP-8, and JP-8+100. Most preferably
the jet fuel is a JP-8 based fuel such as neat JP-8 or the
formulated JP-8+100.
[0026] Jet Fuel A and Jet Fuel A-1 are kerosene-type fuels with Jet
Fuel B being a "wide cut" fuel. Jet A is used for many domestic
commercial flights in the U.S. Most preferably, the CFREAs of the
invention are used to increase the cold flow characteristics of
military jet fuels such as JP-5, JPTS, JP-7, JP-8, and JP-8+100.
JP-5 is currently used by the U.S. Navy with JP-8 and JP-8+100 used
by the Air Force. These fuel types are summarized in the following
Table 1.
1TABLE 1 U.S. Military Jet Fuel Freeze Year Point Intro- .degree.
C. Flash Fuel duced Type Max Point Comments JP-5 1952 kerosene -46
60 JPTS 1956 kerosene -53 43 High thermal stability JP-7 1960
kerosene -43 60 JP-8 1979 kerosene -47 38 U.S. Air Force JP-8 + 100
1998 kerosene -47 38 U.S. Air Force, contains additives for
improved thermal stability JP = jet propulsion Source: Chevron
"Aviation Fuels" Technical Review.
[0027] On a 100% actives basis, the CFREA is preferably added to
the jet fuel in an amount of about 1-7,500 mg/L of the jet fuel.
More preferably, the CFREA is added in an amount of between about
250-5,000 mg/L, most preferably about 4,000 mg/L, as actives. The
jet fuel/CFREA blend is capable of improving the cold flow rate of
jet fuel, specifically, JP-8 based jet fuel at fuel temperatures on
the order of about -53.degree. C. to about -56.degree. C.
Experimental results have indicated that the CFREAs when blended
with JP-8 based jet fuel in accordance with the invention improve
cold flow rates of the fuel so that they are, as measured in
accordance with Table 2 and the test system described, on the order
of about 0.68 (g/s) and greater at fuel temperatures of about
-53.degree. C. to about -56.degree. C.
[0028] The polymers of the invention can be employed in combination
with conventional fuel additives such as dispersants, antioxidants,
and metal deactivators. Such additives are known to those skilled
in the art, for example see U.S. Pat. Nos. 5,596,130 and
5,614,081.
[0029] The jet fuel cold flow enhancement agents are preferably
used in combination with an adjuvant component comprising an
oil-soluble polar nitrogen-containing compound. These are set forth
in U.S. Pat. No. 4,211,534 (Feldman) incorporated by reference
herein. Basically, as stated in the '534 specification, these
compounds are oil-soluble amine salts and/or amides that are
generally formed by reaction of at least one molar proportion of
hydrocarbyl acid having 1-4 carboxyl groups or their anhydrides
with a hydrocarbyl substituted primary, secondary, and/or tertiary
amine.
[0030] In the case of polycarboxylic acids, or anhydrides, all of
the acid groups may be converted to amine salts or amides, or part
of the acid groups may be left unreacted.
[0031] The term "hydrocarbyl" as defined is U.S. Pat. No. 4,211,534
includes groups that may be branched or straight chain, saturated
or unsaturated, aliphatic cycloaliphatic, aryl, alkaryl,
substituted derivatives thereof and the like. Typically, these
hydrocarbyl groups will consist of from about 4-24 carbon atoms,
more preferably 10-20 carbon atoms. In general, the resultant
compound should contain sufficient hydrocarbyl content so as to be
soluble in the fuel matrix.
[0032] Exemplary hydrocarbyl substituted acids and anhydrides
include, but are not limited to, hexanoic acid, lauric acid,
palmitic acid, steric acid, behenic acid, benzoic acids,
1,2,4,5-benzenetetracarboxylic dianhydride,
1,2-cyclohexanedicarboxylic anhydride, ethylenediaminetetraacetic
dianhydride, salicylic acid, succinic acid, succinic anhydride,
alkenyl succinic anhydrides, polyisobutenyl succinic anhydrides
(PIBSA), phthalic acids, phthalic anhydride, naphthenic acids,
naphthenic anhydrides, and the like. Particularly preferred is
phthalic anhydride.
[0033] The hydrocarbyl substituted amines may be primary,
secondary, or tertiary; preferably primary or secondary.
[0034] Exemplary hydrocarbyl substituted primary amines include,
but are not limited to, coco amine, tallow amine, hydrogenated
fatty primary amine, 2-ethylhexylamine, n-dodecyl amine,
C.sub.12-14 or C.sub.16-22 tertiary alkyl primary amines from Rohm
and Haas Company marketed under the trade name Primene.RTM.,
mixtures thereof and the like. Particularly preferred is the
C.sub.16-22 tertiary alkyl primary amine marketed by Rohm and Haas
Company under the trade name Primene.RTM. JM-T.
[0035] Exemplary hydrocarbyl substituted secondary amines include,
but are not limited to, dicocoalkylamine, didecylamine,
dioctadecylamine, ditallowamine, dihydrogenated tallowalkylamine,
mixtures thereof and the like. Particularly preferred is
dihydrogenated tallowalkylamine which is commercially available
from Akzo Nobel Corporation under the trade name Armeen.RTM.
2HT.
[0036] As would be understood by one skilled in the art in view of
the present disclosure, it is intended that the aforementioned
examples do not in any way limit the description of the
nitrogen-containing compounds. Furthermore, it is to be understood
that ester analogs derived from a hydrocarbyl alcohol, and
hydrocarbyl sulfo acid analogs such as those derived from
o-sulphobenzoic acid or its anhydride, as described in European
Patent Application No. 0261959, are also within the purview of the
present invention.
[0037] An especially preferred group of polar nitrogen-containing
compounds is the mixed amine salt/amides derived from reaction of
hydrocarbyl acid (having two or more carboxyl groups) or its
anhydrides as set forth above with a hydrocarbyl secondary amine.
The resulting intermediate amide acid is then neutralized with a
primary amine.
[0038] Generally, the preferred group of polar nitrogen-containing
compounds can be represented by the formula 5
[0039] wherein Z is a divalent organic radical, R.sub.5 and R.sub.6
and R.sub.7 are independently chosen from C.sub.10-C.sub.40
hydrocarbyl groups. The hydrocarbyl groups include straight or
branched chain, saturated or unsaturated aliphatic, cycloaliphatic,
aryl or alkylaryl moieties. These hydrocarbyl groups may contain
other groups or atoms such as hydroxy groups, carbonyl groups,
ester groups, oxygen, sulfur, or chlorine groups. As stated above,
the hydrocarbyl groups may be on the order of C.sub.10-C.sub.40
with the range of C.sub.14-C.sub.24 even more preferred. The
R.sub.5, R.sub.6, and R.sub.7 groupings can also represent mixtures
of different hydrocarbyl groups. Preferably, R.sub.7 .noteq.R.sub.5
or R.sub.6.
[0040] The resulting compound should contain sufficient hydrocarbon
content to be oil-soluble.
[0041] The preferred oil-soluble, polar nitrogen-containing
compound is prepared by initial reaction of a hydrocarbyl acid or
its anhydride and a secondary amine, such as the Armeen.RTM. 2HT.
Then, the resulting mixed amine salt/amide is neutralized with a
primary amine such as the commercially available Primene.RTM. JM-T
product. Approximately equimolar amounts of the reactants are used,
resulting in a mixed, substituted amide/amine salt.
[0042] The most preferred polar nitrogen-containing compound is an
oil-soluble mixed amide/amine salt formed via reaction of equimolar
amounts of phthalic anhydride with the secondary amine, Armeen.RTM.
2HT. The product of this reaction is then further reacted with an
equimolar amount of the primary amine, Primene.RTM. JM-T to form
benzoic acid, 2-[(bis(hydrogenated tallow alkyl)amino)
carbonyl]-C.sub.16-C.sub.22 tert-alkyl amine salt having the
structural formula: 6
[0043] wherein R.sub.5 and R.sub.6 are mixtures of C.sub.16 and
C.sub.18 hydrocarbon from the commercially available tallowamine
product, and R.sub.6 is a mixture of C.sub.18-22 hydrocarbons from
the commercially available Primene.RTM. JM-T product.
[0044] The adjuvant nitrogen compounds can be used in amounts
similar to those given above in conjunction with CFREA dosage.
[0045] The invention will be described further in conjunction with
the following examples that are included for illustrative purposes
only and should not be construed to limit the invention.
EXAMPLE 1
Preparation of Poly[lauryl methacrylate]
[0046] To a 300 ml four-necked reaction flask equipped with a
mechanical overhead stirrer, thermocouple, reflux condenser,
nitrogen sparge tube, addition port with septum and a heating
mantle was added lauryl methacrylate (15.0 g, 96% purity),
n-dodecyl mercaptan (0.15 g, 1.3% on a molar basis) and toluene (30
ml). The resulting solution was then heated to 100.degree. C. under
nitrogen sparge with mixing. An initiator solution comprising AIBN
(0.23 g) dissolved in toluene (10 ml) was then added to the reactor
at a rate of 0.077 ml/min. Upon completion of the initiator
solution addition, the reactor was maintained at 100.degree. C. for
an additional two hours before cooling down to room temperature.
The resultant solution was then concentrated in vacuo to remove the
toluene solvent to produce the polymer additive.
EXAMPLE 2
Preparation of Poly[decyl methacrylate]
[0047] To the reactor set-up as described in Example 1 was added
decyl acrylate (10.0 g, 100% purity), n-dodecyl mercaptan (0.12 g,
1.3% on a molar basis) and toluene (50 ml). The resulting solution
was then heated to 100.degree. C. under nitrogen sparge with
mixing. An initiator solution comprising AIBN (0.155 g) dissolved
in toluene (8 ml) was then added to the reactor at rate of 0.039
ml/min. Upon completion of the initiator solution addition, the
reactor was maintained at 100.degree. C. for an additional two
hours before cooling down to the room temperature. The resultant
solution was then concentrated in vacuo to remove the toluene
solvent to produce the polymer additive.
EXAMPLE 3
Preparation of Poly[tridecyl methacrylate]
[0048] To the reactor set-up as described in Example 1 was added
tridecyl methacrylate (15.0 g), n-dodecyl mercaptan (0.16 g, 1.3%
on a molar basis) and toluene (26 ml). The resulting solution was
then heated to 100.degree. C. under nitrogen sparge with mixing. An
initiator solution comprising AIBN (0.3 g) dissolved in toluene
(8.7 ml) was then added to the reactor at a rate of 0.3 ml/min.
Upon completion of the initiator solution addition, the reactor was
maintained at 100.degree. C. for an additional two hours before
cooling down to the room temperature. The resultant solution was
then concentrated in vacuo to remove the toluene solvent to produce
the polymer additive.
EXAMPLE 4
Preparation of Poly[vinyl decanoate]
[0049] To the reactor set up as described in Example 1 was added
vinyl decanoate (10.0 g) and toluene (26 ml). The resulting
solution was then heated to 60.degree. C. under nitrogen sparge
with mixing. An initiator solution comprising AIBN (1.0 g) of
dissolved in toluene (50 ml) was then added in one shot. Upon
completion of the initiator solution addition, the reactor was
maintained at 60.degree. C. for an additional four hours before
cooling down to the room temperature. The resultant solution was
then concentrated in vacuo to remove the toluene solvent to produce
the polymer additive.
EXAMPLE 5
Preparation of Poly[lauryl methacrylate]
[0050] To the reactor set-up as described in Example 1 was added
Aromatic 100 solvent (15.0 g). The resulting solution was then
heated to 90.degree. C. under a nitrogen sparge with mixing. A
monomer solution comprised of lauryl methacrylate (15.0 grams,
96%), and n-dodecyl mercaptan (1.6 grams) and Aromatic 100 solvent
(15.0 g) was then added to the reactor at rate of 0.59 ml/min while
simultaneously charging an initiator solution comprised of lauroyl
peroxide (3.6 g) dissolved in toluene (20 g) at rate of 0.21
ml/min. Upon completion of the initiator solution addition, the
reactor was maintained at 90.degree. C. for an additional two hours
before cooling down to the room temperature.
EXAMPLE 6
Preparation of Poly[lauryl methacrylate] with a Branching Agent
[0051] As in Example 5, except the monomer solution also comprised
1,4-butanediol dimethacrylate (0.12 g).
EXAMPLE 7
Preparation of Poly[lauryl methacrylate] Inserting an Ester Linkage
into the Polymer Backbone
[0052] To the reactor set-up as described in Example 1 was added
lauryl methacrylate (14.4 g, 96% purity), 2-methylene-1,3-dioxepane
(0.33 g), n-dodecyl mercaptan (0.18 g, 1.3% on a molar basis) and
Aromatic 100 solvent (25 ml). The resulting solution was then
heated to 90.degree. C. under nitrogen sparge with mixing. An
initiator solution comprising AIBN (0.31 g) dissolved in toluene
(12.62 g) was then added to the reactor at a rate of 0.15 ml/min.
Upon completion of the initiator solution addition, the reactor was
maintained at 90.degree. C. for an additional two hours before
cooling down to room temperature.
Example A (Not of the Invention)
Preparation of Poly[methyl acrylate] Precursor
[0053] A 2-liter four-necked reaction flask equipped with a
mechanical overhead stirrer, thermocouple, reflux condenser,
nitrogen sparge tube, two additional funnels, and a heating mantle.
The first addition funnel was charged with methyl acrylate (200 g)
dissolved in toluene (100 ml). The second addition funnel was
charged with benzoyl peroxide (4 g, 97% purity) dissolved in
toluene (615 g). The reaction flask was then charged with 75 g of
methyl acrylate monomer solution form the first addition funnel and
125 g of benzoyl peroxide solution from the second addition funnel.
The reaction flask was then slowly heated to 70.degree. C. After
maintaining 70.degree. C. for 30 minutes, simultaneous drop-wise
addition of the remaining methyl acrylate and benzoyl peroxide
solutions were conducted over a period of 140 and 155 minutes,
respectively. During the feeds an exotherm took place, raising the
temperature to 105.degree. C. Upon completion of the additions, the
reaction temperature set point was raised to 100.degree. C. Thirty
minutes later, a solution of benzoyl peroxide (0.5 g) dissolved in
toluene (10 ml) was added to the reaction flask in one portion.
After maintaining the reaction temperature at 100.degree. C. for an
additional hour, heating was removed. The resultant polymer
solution was then concentrated in vacuo to remove the toluene
solvent to produce the poly(methyl acrylate) precursor.
EXAMPLE 8
Preparation of Transesterified Poly[methyl acrylate]
[0054] To a four-necked reaction flask equipped with a mechanical
overhead stirrer, thermocouple, reflux condenser, nitrogen sparge
tube, Dean-Stark trap and a heating mantle was added of Example A
(20 g), toluene (50 ml), ALFOL 1012HA alcohol (29.5 g, a mixture of
C.sub.10, C.sub.12 and C.sub.14 alcohols available from Sasol North
America), and ISOFOL 14 T alcohol (4.35 g, a mixture of C.sub.12,
C.sub.14, and C.sub.16 alcohols available from Sasol North
America). The reaction mixture was then heated to 90.degree. C.
with stirring. Thereafter, methanesulfonic acid (0.78 g, 70% in
water) was added to the reaction mixture in one portion. Forty
minutes afterward, the reaction temperature set was raised to
140.degree. C. After maintaining the reaction temperature at
100.degree. C. for an additional five hours, heating was removed.
The resultant polymer solution was then concentrated in vacuo to
remove the toluene solvent to produce the poly[alkyl acrylate]
additive.
EXAMPLE 9
Preparation of Poly[lauryl methacrylate]
[0055] As in Example 1 except at a larger scale (basis: lauryl
methacrylate, 218.2 g, 96% purity).
[0056] The physical characterizations of Examples 1-9 are
summarized in Table 2 below. The molecular weights were determined
by GPC analysis referenced to poly[styrene] standards.
2TABLE 2 Polymer Additive Characterization Monomer Conversion
Example (mole %) Mn Mw Mw/Mn 1 94.5 6900 14700 2.14 2 89.4 3450
6590 1.91 3 87.7 1350 11600 8.58 4 85.1 6480 34200 5.28 5 96.6 2359
3033 1.29 6 97.8 2116 2991 1.41 7 97.1 7386 11127 1.51 A 97.8 1500
50400 33.51 8 100.0 14300 104000 7.23 9 94.5 9098 20053 2.20
[0057] Screening results of the polymeric additive of the present
invention in the CAST apparatus are provided in Table 3 below. In
general, the CAST apparatus consists of two 500 ml flasks, one at
atmospheric pressure and one sealed, connected via a 1/4-inch
Teflon tube. A known amount of fuel is charged to the flask at
atmospheric pressure, and the apparatus is cooled to the desired
test temperature in an environmental chamber. Once cooled to the
desired temperature, vacuum (2-inch Hg) is applied to the sealed
flask. The effectiveness of an additive is determined by measuring
the time it takes for the fuel to flow to the sealed flask and the
amount of fuel remaining in the atmospheric flask after the fuel
flow ceases.
[0058] As shown in Table 3, at approximately -53.degree. C., the
untreated fuel has solidified and exhibited 100% hold up and
essentially no fuel flow. Additions of the additive of the present
invention to the fuel dramatically improved the cold flow
properties at approximately -53.degree. C. to -56.degree. C. as
evidenced by a substantial decrease in hold up and increase in fuel
flow.
3TABLE 3 CAST Testing Results in JP-8 Fuel Example Conc. Fuel Temp
Hold up Flow Rate # (mg/L)* (.degree. C.) (%) (g/s) NA -53.5 100 NA
1 16000 -53.0 7 1.23 2 16000 -53.2 9 0.95 3 16000 -53.3 6 1.15 4
16000 -53.0 13 1.03 4 16000 -53.0 18 0.99 5 16000 -55.3 7 1.59 6
16000 -56.3 11 1.18 7 16000 -57.2 32 0.83 8 16000 -52.7 6 1.34 8
16000 -53.0 7 0.88 8 16000 -53.6 7 0.77 8 16000 -52.9 8 0.68 9
16000 -52.9 7 1.26 *25% active solutions
[0059] Description of the U-2 Wing Simulator Device is provided by
Ervin, J. S. et al., "Investigation of the Use of JP-8+100 with
Cold Flow Enhancer Additives as a Low-Cost Replacement for JPTS",
Energy & Fuels, 13, 1246-1251 (1999). Screening results for the
polymeric additive of the present invention in the U-2 Wing
Simulator Device are summarized in Table 4 below. As shown, at
approximately -53.degree. C., the untreated fuel exhibited
significant hold-up. Addition of the additive of the present
invention to the fuel dramatically improved the cold flow
properties at approximately -53.degree. C. as evidenced by a
substantial decrease in hold up.
4TABLE 4 U-2 Wing Simulator Testing Results in JP-8 Fuel Initial
Final Conc. Tank Weight Weight Hold up Example (mg/L)* Temp
(.degree. C.) (lbs) (lbs) (%) NA -49 196.5 192.0 2 NA -52 198.0
107.2 46 9 16000 -54 201.8 185 8 *25 wt % active solutions
[0060] When the polymeric CFREAs of the invention are conjointly
used with an oil-soluble, polar nitrogen-containing compound
adjuvant, both components can be provided in a convenient one drum
approach, dissolved in a suitable organic solvent such as toluent,
kerosene, HAN or the like. The polymeric CFREA is present in such
compositions in a molar amount of about 0.01-100 moles polymeric
CFREA to about 1.0 moles of the polar nitrogen-containing compound
adjuvant. At present, it is preferred to use the polymeric CFREA,
poly[lauryl methacrylate] and polar nitrogen-containing compound
detailed in Example 12.
[0061] Additional CFREA polymers and an oil-soluble polar,
nitrogen-containing compound used as an adjuvant treatment were
prepared and tested as follows:
EXAMPLE 10
Preparation of Poly[lauryl methacrylate]
[0062] To a two-liter four-necked reaction flask equipped with a
mechanical overhead stirrer, thermocouple, reflux condenser,
nitrogen sparge tube, addition port with septum and a heating
mantle was added lauryl methacrylate (96%, 218.2 g, 0.823 mole),
n-dodecyl mercaptan (98.5%, 2.2 g, 0.01 mole) and toluene (400 ml).
The resulting solution was heated to 95.degree. C. under nitrogen
sparge with mixing. An initiator solution consisting of 5.5 grams
of 2,2'-azobisisobutyronitrile (AIBN) dissolved in 50 ml of toluene
was then added to the reactor at a rate of 2.0 ml/min. Upon
completion of the initiator solution addition, the reaction was
maintained at 95.degree. C. for an additional two hours before
cooling to room temperature. The resultant solution was
concentrated in vacuo to remove the toluene solvent, then diluted
in Aromatic (Exxon) 100 to yield a 25 wt % polymer solution (i.e.,
25% actives). 95.0% conversion of the monomer was determined by
.sup.1H NMR.
EXAMPLE 11
Preparation of Poly[tridecyl methacrylate]
[0063] To a 300-ml four-necked reaction flask equipped with a
mechanical overhead stirrer, thermocouple, reflux condenser,
nitrogen sparge tube, addition port with septum and a heating
mantle was added tridecyl methacrylate (100%, 60.0 g, 0.223 mole),
n-dodecyl mercaptan (98.5%, 0.6 g, 0.003 mole) and Aromatic 100
(120 ml). The resulting solution was then heated to 90.degree. C.
under nitrogen sparge with mixing. An initiator solution consisting
of 1.12 grams of AIBN dissolved in 40 ml of toluene was then added
to the reactor at a rate of 1.1 ml/min. Upon completion of the
initiator solution addition, the reaction was maintained at
90.degree. C. for an additional two hours before cooling to room
temperature. The resultant solution was then diluted further with
A-100 to yield a 25 wt % active solution. 93.2% Conversion of the
monomer was determined by .sup.1H NMR.
EXAMPLE 12
Preparation of the Nitrogen-Containing Adjuvant Compound Benzoic
acid, 2-[(bis-(hydrogenated tallow
alkyl)amino)carbonyl)]-C.sub.16-22-tert alkyl amine salt.
[0064] To a four-necked reaction flask equipped with a mechanical
overhead stirrer, thermocouple, reflux condenser, nitrogen sparge
tube, addition port with septum and a heating mantle was added
phthalic anhydride (99%, 5.0 g, 0.03342 mole) and Armeen.RTM. 2HT
(17.0 g, 0.03342 mole amine). The resulting wax mixture was then
heated to 90.degree. C. under nitrogen with mixing and held for
four hours. Primene.RTM. JM-T (10.9 g, 0.03342 mole amine) was then
added to the reactor at 90.degree. C. over an eight-minute period,
after which the batch was maintained at 90.degree. C. for an
additional four hours before cooling to room temperature to yield a
wax like material. This was then diluted in Aromatic 100 to yield a
25 wt % solution of the nitrogen-containing compound.
EXAMPLE 13
Preparation of Benzoic acid, 2-[(bis-(hydrogenated tallow
alkyl)amino)carbonyl)]-C.sub.16-22-tert alkyl amine salt.
[0065] This preparation was a scaleup of Example 12. To a
four-necked reaction flask equipped with a mechanical overhead
stirrer, thermocouple, reflux condenser, nitrogen sparge tube,
addition port with septum and a heating mantle was added phthalic
anhydride (99%, 344.74 g, 2.30 mole) and Armeen.RTM. 2HT (1165.75
g, 2.30 mole amine). The resulting wax mixture was then heated to
90.degree. C. under nitrogen with mixing and held for one hour.
Primene.RTM. JM-T (757.51 g, 2.3 mole amine) was then added to the
reactor at 90.degree. C. over an fifteen-minute period, after which
the batch was maintained at 90.degree. C. for an additional one
hour before adding the Aromatic 100 solvent (6780.36 g) to yield a
25 wt % solution of the nitrogen-containing compound.
[0066] Screening results of the Examples 10-13 additives of the
present invention in the CAST apparatus are provided in Table 5
below. As can be seen, at approximately -53.degree. C. the
untreated fuel has solidified and exhibited 100% holdup and
essentially no fuel flow. Addition of the additives of the present
invention as single component treatments to the fuel dramatically
improved the cold flow properties at approximately -53.degree. C.
as evidenced by a substantial decrease in hold up and increase in
fuel flow. In addition, blends of the polymeric CFREA with the
polar nitrogen-containing adjuvant compound also exhibited
improvement in the cold flow properties of the fuel.
5TABLE 5 CAST Testing Results in JP-8 Fuel Additive Fuel Temp
Holdup Flow Additive 1 Additive 2 Ratio Conc. (mg/L)* (.degree. C.)
(%) Rate (g/s) None None N/A N/A -53.5 100 N/A Example 10 None N/A
8000 -52.7 7 1.38 Example 10 None N/A 16000 -52.9 7 1.26 Example 11
None N/A 8000 -53.6 7 1.35 Example 11 None N/A 16000 -53.3 6 1.15
Example 12 None N/A 8000 -52.7 10 1.34 Example 12 None N/A 16000
-53.3 9 0.93 Example 13 None N/A 12000 -57.8 25 0.47 Example 13
None N/A 12000 -55.1 7 0.85 Example 13 None N/A 14000 -57.0 13 0.83
Example 13 None N/A 14000 -55.2 10 1.06 Example 13 None N/A 16000
-57.1 8 0.82 Example 13 None N/A 16000 -55.2 8 0.93 Example 10
Example 12 50/50 6000 -53.3 13 1.34 Example 10 Example 12 50/50
16000 -54.8 15 1.50 Example 11 Example 12 50/50 6000 -53.1 7 1.50
*as 25 wt % active solutions, total addition
[0067] Low temperature viscosity studies of the treated fuel were
carried out using a scanning Brookfield Viscometer in the
temperature range of -5.degree. C. to -60.degree. C. as described
by S. Zabarnick and M. Vangsness, Petroleum Chemistry Preprints
2002, 47(3), pp. 243-246 (2002). The results of this testing are
given in Table 6. As used in the table, the "knee temperature" is
defined as the temperature at which a rapid viscosity increase
occurs due to crystal formation. It is desirable to have the knee
temperature for a treated fuel to be shifted to a lower temperature
relative to the neat fuel. It is also highly desirable to minimize
the rate of viscosity increase as the fuel is cooled below the knee
temperature.
[0068] It can be seen from the data presented in Table 6 that the
additives of the present invention, as either stand alone
treatments or as blends of the polymeric CFREA with the
nitrogen-containing adjuvant compound, lower the knee temperature
of the fuel. As shown in FIG. 1, blending the additives results in
a significant reduction in the rate of increase of the viscosity of
the fuel compared to use of one of the polymeric CFREA singly
(compare curve "B" to curves "C", "D", and "E").
[0069] FIG. 2 shows that, when the polymeric CFREA is utilized as a
stand alone treatment, the rate of increase of the fuel are also
effected by varying the molecular weight or use of a branching
agent (compare curves "G" and "H" of FIG. 2 to "B" of FIG. 1). In
addition, insertion of ester functionality into the backbone the
polymeric CFREA did not adversely affect its cold flow enhancement
properties (compare curves "H" of FIG. 2 to "B" of FIG. 1).
[0070] The following reference used in FIGS. 1 and 2 show viscosity
versus temperature plot data for the following treatments in JP-8
fuel.
6 Letter Additive 1* Additive 2* A None None B 16,000 mg/L Ex. 10
None C 12,000 mg/L Ex. 10 4,000 mg/L Ex. 12 D 8,000 mg/L Ex. 10
8,000 mg/L Ex. 12 E 4,000 mg/L Ex. 10 12,000 mg/L Ex. 12 F 16,000
mg/L Ex. 5 None G 16,000 mg/L Ex. 6 None H 16,000 mg/L Ex. 7 None
*All dosages are in terms of 25 wt % actives.
[0071]
7TABLE 6 Low Temperature Viscosity Results - Knee Temperature in
JP-8 Fuel Additive Conc. Knee Additive 1 Additive 2 Ratio (mg/L)*
Temp (.degree. C.) None None N/A N/A -52.0 Example 10 None N/A
16000 -55.7 Example 12 None N/A 16000 -54.0 Example 10 Example 12
50/50 16000 -56.4 Example 11 Example 12 50/50 16000 -56.0 Example 5
None N/A 16000 -55.1 Example 6 None N/A 16000 -54.9 Example 7 None
N/A 16000 -55.5 *25 wt % actives
[0072] While the specification above has been drafted to include
the best mode of practicing the invention as required by the patent
statutes, the invention is not to be limited to that best mode or
to other specific embodiments set forth in the specification. The
breadth of the invention is to be measured only by the literal and
equivalents constructions applied to the appended claims.
* * * * *