U.S. patent application number 10/809882 was filed with the patent office on 2004-11-04 for diesel fuel composition and a method to improve filterability of diesel fuel.
Invention is credited to Gande, Matthew E., Gatechair, Leslie R., Venkatadri, Ramraj, Waynick, Andrew, Westbrook, Steve.
Application Number | 20040216370 10/809882 |
Document ID | / |
Family ID | 33131856 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216370 |
Kind Code |
A1 |
Gande, Matthew E. ; et
al. |
November 4, 2004 |
Diesel fuel composition and a method to improve filterability of
diesel fuel
Abstract
Disclosed is a stabilized diesel fuel composition comprising a)
a diesel fuel with a cetane number less than or equal to 50, b) an
effective amount of at least one compound selected from the group
consisting of the cetane improvers and c) i) an effective
stabilizing amount of at least one compound selected from the group
consisting of the stable nitroxide compounds or ii) an effective
synergistic stabilizing amount of at least one compound selected
from the group consisting of the stable nitroxide compounds and at
least one antioxidant compound selected from the group consisting
of the aromatic amine antioxidants and the hindered phenolic
antioxidants. The cetane improvers are for example nitrate esters.
The diesel fuel compositions exhibit improved filterability.
Inventors: |
Gande, Matthew E.; (Danbury,
CT) ; Gatechair, Leslie R.; (Green Cove Springs,
FL) ; Venkatadri, Ramraj; (Ardsley, NY) ;
Waynick, Andrew; (San Antonio, TX) ; Westbrook,
Steve; (San Antonio, TX) |
Correspondence
Address: |
CIBA SPECIALTY CHEMICALS CORPORATION
PATENT DEPARTMENT
540 WHITE PLAINS RD
P O BOX 2005
TARRYTOWN
NY
10591-9005
US
|
Family ID: |
33131856 |
Appl. No.: |
10/809882 |
Filed: |
March 25, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60459020 |
Mar 31, 2003 |
|
|
|
Current U.S.
Class: |
44/322 ; 44/324;
44/412 |
Current CPC
Class: |
C10L 1/1811 20130101;
C10L 1/231 20130101; C10L 1/24 20130101; C10L 1/14 20130101; C10L
1/1852 20130101; C10L 1/232 20130101; C10L 1/1832 20130101; C10L
1/2425 20130101; C10L 1/2222 20130101; C10L 1/2406 20130101; C10L
1/23 20130101; C10L 1/223 20130101 |
Class at
Publication: |
044/322 ;
044/324; 044/412 |
International
Class: |
C10L 001/12; C10L
001/18; C10L 001/22 |
Claims
What is claimed is:
1. A stabilized diesel fuel composition comprising a) a diesel fuel
with a cetane number less than or equal to 50, b) an effective
amount of at least one compound selected from the group consisting
of the cetane improvers and c) i) an effective stabilizing amount
of at least one compound selected from the group consisting of the
stable nitroxide compounds or ii) an effective synergistic
stabilizing amount of at least one compound selected from the group
consisting of the stable nitroxide compounds and at least one
antioxidant compound selected from the group consisting of the
aromatic amine antioxidants and the hindered phenolic
antioxidants.
2. A composition according to claim 1 in which the cetane improvers
are selected from the group consisting of the peroxides,
thioaldehydes, tertiary alkyl primary amines, perketals,
alkylether/peroxide blends, peracids, tetrazoles or triazoles,
N,N-disubstituted organic nitroxides and the organic nitrates.
3. A composition according to claim 1 in which the cetane improvers
are selected from the group consisting of the organic nitrates.
4. A composition according to claim 1 in which the cetane improvers
are selected from the group consisting of the hydrocarbyl nitrates
where hydrocarbyl is a straight or branched chain alkyl of 1 to 24
carbon atoms, straight or branched chain alkyl of 2 to 24 carbon
atoms interrupted by one to three oxygen atoms, straight or
branched chain alkenyl of 3 to 24 carbon atoms, cycloalkyl of 5 to
12 carbon atoms or C.sub.1-C.sub.4alkyl-substituted cycloalkyl of 5
to 12 carbon atoms.
5. A composition according to claim 4 in which hydrocarbyl is
selected from the group consisting of methyl, ethyl, n-propyl,
isopropyl, butyl, amyl, hexyl, heptyl, octyl, isooctyl,
2-ethylhexyl, nonyl, decyl, allyl, cyclopentyl, cyclohexyl,
methylcyclohexyl, cyclododecyl, 2-ethoxyethyl and
2-(2-ethoxyethoxy) ethyl.
6. A composition according to claim 4 in which the hydrocarbyl
nitrate is 2-ethylhexyl nitrate.
7. A composition according to claim 1 where the stable nitroxide
comounds are hindered amine nitroxide compounds that comprise a
nitroxyl moiety flanked by two tertiary carbon atoms where the
flanking tertiary carbon atoms may be further connected by bridging
groups to form five- or six-membered cyclic structures.
8. A composition according to claim 7 where the stable nitroxide
compounds are of the formula 4or are compounds that contain one or
more groups of the formula 5or are of the formula 6where each R is
independently methyl or ethyl, T is a group required to complete a
5- or 6-membered ring and E is a linking group.
9. A composition according to claim 1 where the stable nitroxide
compounds are selected from the group consisting of
bis(1-oxyl-2,2,6,6-tetramethylp- iperidin-4-yl) sebacate,
4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-ethoxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-propoxy-1-oxyl-2,2,6,6-t- etramethylpiperidine,
4-acetamido-1-oxyl-2,2,6,6-tetramethylpiperidine,
1-oxyl-2,2,6,6-tetramethylpiperidine,
1-oxyl-2,2,6,6-tetramethylpiperidin- -4-one,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-t-butyl-benzoate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) succinate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) n-butylmalonate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)phthalate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)isophthalate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) terephthalate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)
hexahydroterephthalate,
N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipamide,
N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)caprolactam,
N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)dodecylsuccinimide,
2,4,6-tris-[N-butyl-N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)]-s-triaz-
ine, 4,4'-ethylenebis(1-oxyl-2,2,6,6-tetramethylpiperazin-3-one),
2-oxyl-1,1,3,3-tetramethyl-2-isobenzazole,
1-oxyl-2,2,5,5-tetramethylpyrr- olidine,
N,N-bis-(1,1,3,3-tetramethylbutyl)nitroxide, N,N-diphenylnitroxyl,
a mixture of mono- and dialkylated
tert-butyl/tert-octyl-N,N-diphenylnitroxyls and a mixture of mono-
and dialkylated nonyl-N,N-diphenylnitroxyls.
10. A composition according to claim 1 where the stable nitroxide
compounds are selected from the group consisting of
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate,
4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-ethoxy-1-oxyl-2,2,6,6-t- etramethylpiperidine,
4-propoxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-acetamido-1-oxyl-2,2,6,6-tetramethylpiperidine,
1-oxyl-2,2,6,6-tetramet- hylpiperidine and
1-oxyl-2,2,6,6-tetramethylpiperidin-4-one.
11. A composition according to claim 1 where the stable nitroxide
is bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate or
4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine.
12. A composition according to claim 1 in which component c) is
present from about 0.05 ppm to about 10,000 ppm, by weight, based
on the weight of the entire formulation.
13. A composition according to claim 1 in which component c) is
present from about 0.1 ppm to about 1000 ppm, by weight, based on
the weight of the entire formulation.
14. A composition according to claim 1 in which component c) is
present from about 0.2 ppm to about 100 ppm, by weight, based on
the weight of the entire formulation.
15. A composition according to claim 1 in which component c) is
present from about 0.5 ppm to about 25 ppm, by weight, based on the
weight of the entire formulation.
16. A composition according to claim 1 comprising an effective
synergistic stabilizing amount of at least one compound selected
from the group consisting of the stable nitroxide compounds and at
least one antioxidant compound selected from the group consisting
of the aromatic amine antioxidants and the hindered phenolic
antioxidants.
17. A composition according to claim 16 in which the ratio of the
stable nitroxide compounds to the antioxidant compounds is from
about 1:99 to about 95:5 parts by weight.
18. A composition according to claim 16 in which the ratio of the
stable nitroxide compounds to the antioxidant compounds is from
about 1:10 to about 10:1 parts by weight.
19. A composition according to claim 16 in which the ratio of the
stable nitroxide compounds to the antioxidant compounds is from
about 1:5 to about 5:1 parts by weight.
20. A composition according to claim 16 in which the ratio of the
stable nitroxide compounds to the antioxidant compounds is from
about 1:3 to about 3:1 parts by weight.
21. A process for improving the filterability and improving the
cetane number of a diesel fuel, which process comprises adding to a
diesel fuel with a cetane number less than or equal to 50, b) an
effective amount of at least one compound selected from the group
consisting of the cetane improvers and c) i) an effective
stabilizing amount of at least one compound selected from the group
consisting of the stable nitroxide compounds or ii) an effective
synergistic stabilizing amount of at least one compound selected
from the group consisting of the stable nitroxide compounds and at
least one antioxidant compound selected from the group consisting
of the aromatic amine antioxidants and the hindered phenolic
antioxidants.
Description
[0001] This application claims the benefit under 35 USC 119(e) of
U.S. provisional application No. 60/459,020, filed Mar. 31,
2003.
[0002] The present invention is aimed at stabilized diesel fuel
compositions that comprise certain cetane improvers. The stabilized
diesel fuel compositions exhibit improved filterability. The diesel
fuel compositions comprise stabilizers selected from the group
consisting of the stable nitroxide compounds and optionally the
aromatic amine and hindered phenolic antioxidants. The cetane
improvers are for example nitrate esters.
[0003] The present compositions form reduced insoluble material
that may clog fuel lines and filters.
[0004] Diesel fuel is the second most used fuel for internal
combustion engines. It is used extensively in trucks, buses, and in
heavy equipment, as well as in marine and stationary applications.
Its use in passenger cars is also growing due to the higher fuel
efficiency of compression ignition engines over spark ignition
engines.
[0005] In diesel engines, the fuel is ignited during the
compression stroke by the heat generated due to the compression of
the air in the cylinder. There is a period between when the fuel is
injected into the cylinder and when the compression generated heat
induces the fuel to burn. This period is known as the ignition
delay, and if too long, diesel knock can occur. Other effects of
long ignition delay are power loss, increased carbon monoxide
production, and incomplete combustion, which leads to increased
hydrocarbons and particulates in the exhaust. Recently, there has
been pressure from regulatory agencies to reduce these
environmental pollutants.
[0006] An indication of how well a particular fuel will perform in
a compression ignition engine is the cetane number. Poor fuels with
a long iginition delay have a low cetane number, while better fuels
have higher cetane numbers. Typical values are 40-48 for a
commercial diesel fuel, and greater than 50 for a premium product.
In addition to the environmental benefits, a high cetane fuel can
decrease engine deposits and facilitate cold temperature
starting.
[0007] Due to increased demand, there has been an increase in the
use of cracked materials for diesel fuel. Unfortunately, catalytic
cracker, hydrocracker and coker distillates have low cetane
numbers. In some cases the cetane number is below 40, which is the
minimum cetane number allowed by diesel fuel specifications.
Additives known as cetane improvers have been developed that will
raise the cetane number of a diesel fuel to acceptable levels.
[0008] Nitrate ester cetane improvers are disclosed for example in
U.S. Pat. Nos. 4,705,534, 5,258,049 and 5,482,518.
[0009] Cetane improvers may destabilize diesel fuel. In a typical
thermal stability test, ASTM D6468, the fuel is aged at 150.degree.
C. (302.degree. F.) for either 1.5 or 3.0 hours. Under these
conditions, a thermally stable, low cetane number fuel would
produce very little deposits. If a commercial cetane improver such
as 2-ethylhexyl nitrate was added, the fuel quality with respect to
combustion would increase, but more deposits would be formed in the
thermal stability test. In actual engines, these deposits could
lead to plugged fuel lines and clogged fuel filters.
[0010] EP0947577 teaches a fuel composition that includes a cetane
improver and tertiary alkyl amine thermal stabilizers. U.S.
published app. No. 2002/0026743 discloses the use of certain
heterocyclic ring systems with large hydrocarbyl groups, such as
polyisobutenyl succinimide, to increase the thermal stability of a
cetane improver in a fuel composition.
[0011] However, despite efforts to prevent the formation of
insoluble material induced by the cetane improver, there remains a
need to stabilize diesel fuels more effectively. The need is
greatest for those fuels that are more sensitive to the deleterious
effects of the cetane improver.
[0012] Surprisingly, it has been found that hindered nitroxide
stabilizers are especially suited as additives which increase the
thermal stability of diesel fuels that contain cetane improvers.
The hindered nitroxide stabilizers serve to reduce the formation of
insoluble material, or deposits in the diesel fuel and thereby
increase filterability and prevent plugging of fuel filters.
[0013] U.S. Pat. No. 5,711,767 discloses the use of stable
nitroxide compounds to reduce gum formation in gasoline. U.S. Pat.
No. 5,460,634 teaches the use of stable nitroxide compounds to
reduce emissions produced by the combustion of fuels.
DETAILED DISCLOSURE
[0014] The present invention pertains to a stabilized diesel fuel
composition comprising
[0015] a) a diesel fuel with a cetane number less than or equal to
50,
[0016] b) an effective amount of at least one compound selected
from the group consisting of the cetane improvers and
[0017] c) i) an effective stabilizing amount of at least one
compound selected from the group consisting of the stable nitroxide
compounds or
[0018] ii) an effective synergistic stabilizing amount of at least
one compound selected from the group consisting of the stable
nitroxide compounds and at least one antioxidant compound selected
from the group consisting of the aromatic amine antioxidants and
the hindered phenolic antioxidants.
[0019] The additive combination of the stable nitroxide and the
antioxidants of component c) is synergistic towards providing
thermal stability.
[0020] The diesel fuel is present as the major constituent, that is
present in greater than 50 percent by weight of the total
formulation.
[0021] Hydrocarbon based diesel fuels are comprised in general of
mixtures of hydrocarbons which fall within the diesel fuel boiling
range, typically about 160.degree. C. to about 370.degree. C., for
example a 90% distillation point between 282.degree. C. and
338.degree. C. (ASTM D-396 and D-975). The diesel fuel may have a
specification that includes a minimum flash point of 38.degree. C.
The diesel fuels are middle distillate fuels since they comprise
the fractions which distill after gasoline. The diesel fuels of the
invention have a low sulfur content, for example not more than 500
ppm by weight, for instance not more than 100 ppm or not more than
60 ppm by weight sulfur. Aromatic content is in the range of 10-50%
by volume, for example about 10-35% by volume. Lower sulfur content
leads to lower aromatics.
[0022] Typical cetane number values are 40-48 for a commercial
diesel fuel. The present diesel fuels have a cetane number of less
than 50. That is, the present diesel fuels have an inherent cetane
number of less than 50 (prior to addition of any cetane
improver).
[0023] The cetane improvers are for example selected from the group
consisting of peroxides, for example di-t-butylperoxide,
thioaldehydes, tertiary alkyl primary amines, perketals as
disclosed in U.S. Pat. No. 5,011,503, alkylether/peroxide blends as
disclosed in U.S. Pat. No. 5,520,710, peracids as disclosed in
EP0537931, tetrazoles and triazoles as disclosed in U.S. Pat. No.
4,632,674, N,N-disubstituted organic nitroxides as disclosed in
U.S. Pat. No. 4,398,505, organic nitrates, and mixtures thereof.
The disclosures of the U.S. patents are hereby incorporated by
reference.
[0024] The cetane improvers are in particular organic nitrates, for
example nitrate esters, or alkyl nitrates. Nitrate ester cetane
improvers are disclosed for example in U.S. Pat. Nos. 4,705,534,
5,258,049 and 5,482,518, the disclosures of which are hereby
incorporated by reference.
[0025] The nitrate esters are for example hydrocarbyl nitrates
where hydrocarbyl is a straight or branched chain alkyl of 1 to 24
carbon atoms, straight or branched chain alkyl of 2 to 24 carbon
atoms interrupted by one to three oxygen atoms, straight or
branched chain alkenyl of 3 to 24 carbon atoms, cycloalkyl of 5 to
12 carbon atoms or C.sub.1-C.sub.4alkyl-substituted cycloalkyl of 5
to 12 carbon atoms.
[0026] Examples of hydrocarbyl are methyl, ethyl, n-propyl,
isopropyl, butyl, amyl, hexyl, heptyl, octyl, isooctyl,
2-ethylhexyl, nonyl, decyl, allyl, cyclopentyl, cyclohexyl,
methylcyclohexyl, cyclododecyl, 2-ethoxyethyl and
2-(2-ethoxyethoxy) ethyl.
[0027] For example, the present nitrate ester is 2-ethylhexyl
nitrate.
[0028] The nitroxides of this invention are for example those
disclosed in U.S. Pat. Nos. 5,711,767 and 5,460,634, the
disclosures of which are hereby incorporated by reference.
[0029] The nitroxide can be of several different classes. Both
aromatic and aliphatic (often hindered amine) nitroxides are shown
to be effective in the present compositions. The hindered amine
nitroxides are are particular value, that is compounds with a
nitroxyl moiety flanked by two tertiary carbon atoms. The flanking
tertiary carbon atoms may be further connected by various bridging
groups to form cyclic structures such as for example six-membered
piperidines, piperazines, five membered pyrrolidines and the
like.
[0030] The nitroxide stabilizers useful in this invention are for
example of the formula 1
[0031] or are compounds that contain one or more groups of the
formula 2
[0032] where each R is independently methyl or ethyl and T is a
group required to complete a 5- or 6-membered ring.
[0033] Two or more nitroxide groups may be present in the same
molecule by being linked through the T moiety as exemplified below
where E is a linking group. 3
[0034] The stable nitroxide compounds are for example selected from
the group consisting of
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate,
4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-ethoxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-propoxy-1-oxyl-2,2,6,6-t- etramethylpiperidine,
4-acetamido-1-oxyl-2,2,6,6-tetramethylpiperidine,
1-oxyl-2,2,6,6-tetramethylpiperidine,
1-oxyl-2,2,6,6-tetramethylpiperidin- -4-one,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate,
1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-t-butyl-benzoate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) succinate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) n-butylmalonate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) phthalate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) terephthalate,
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)
hexahydroterephthalate,
N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipamide,
N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)caprolactam,
N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)dodecylsuccinimide,
2,4,6-tris-[N-butyl-N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)]-s-triaz-
ine, 4,4'-ethylenebis(1-oxyl-2,2,6,6-tetramethylpiperazin-3-one),
2-oxyl-1,1,3,3-tetramethyl-2-isobenzazole,
1-oxyl-2,2,5,5-tetramethylpyrr- olidine,
N,N-bis-(1,1,3,3-tetramethylbutyl)nitroxide, N,N-diphenylnitroxyl,
a mixture of mono- and dialkylated
tert-butyl/tert-octyl-N,N-diphenylnitroxyls and a mixture of mono-
and dialkylated nonyl-N,N-diphenylnitroxyls.
[0035] The stable nitroxide compounds are for example
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate,
4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-ethoxy-1-oxyl-2,2,6,6-t- etramethylpiperidine,
4-propoxy-1-oxyl-2,2,6,6-tetramethylpiperidine,
4-acetamido-1-oxyl-2,2,6,6-tetramethylpiperidine,
1-oxyl-2,2,6,6-tetramet- hylpiperidine or
1-oxyl-2,2,6,6-tetramethylpiperidin-4-one.
[0036] A specific embodiment is where the nitroxide compound is
bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate or
4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine.
[0037] The aromatic amine antioxidants are for example selected
from the group consisting of 4-(p-toluene-sulfamoyl)diphenylamine,
diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenylamine,
N-phenyl-1-naphthylamine- , N-(4-tert-octylphenyl)-1-naphthylamine,
N-phenyl-2-naphthylamine, octylated diphenylamine, for example
4,4'-di-tert-octyldiphenylamine, 4-n-butylaminophenol,
4-butyrylaminophenol, 4-nonanoylaminophenol,
4-dodecanoylaminophenol, 4-octadecanoylaminophenol,
bis(4-methoxyphenyl)amine,
2,6-di-tert-butyl-4-dimethylaminomethylphenol,
2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane,
N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane,
1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane,
(o-tolyl)biguanide, bis[4-(1',3'-dimethylbutyl)phenyl]amine,
tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and
dialkylated tert-butyl/tert-octyl-diphenylamines, a mixture of
mono- and dialkylated nonyldiphenylamines, a mixture of mono- and
dialkylated dodecyldiphenylamines, a mixture of mono- and
dialkylated isopropyl/isohexyldiphenylamines, a mixture of mono-
and dialkylated tert-butyldiphenylamines,
2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a
mixture of mono- and dialkylated tert-butyl/tert-octylph-
enothiazines, a mixture of mono- and dialkylated
tert-octyl-phenothiazines- , N-allylphenothiazine,
N,N,N',N'-tetraphenyl-1,4-diaminobut-2-ene, phenylenediamine and
N,N'-di-sec-butyl-phenylenediamine.
[0038] The hindered phenolic antioxidants are for example selected
from the group consisting of
[0039] alkylated monophenols, for example
2,6-di-tert-butyl-4-methylphenol- , 2,6-di-tert-butylphenol,
2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,
2,6-di-tert-butyl-4-n-butylphenol,
2,6-di-tert-butyl-4-isobutylphenol,
2,6-dicyclopentyl-4-methylphenol,
2-(.alpha.-methylcyclohexyl)-4,6-dimethylphenol,
2,6-dioctadecyl-4-methyl- phenol, 2,4,6-tricyclohexylphenol,
2,6-di-tert-butyl-4-methoxymethylphenol- , nonylphenols which are
linear or branched in the side chains, for example,
2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6-(1-methylundec-1-yl)-
phenol, 2,4-dimethyl-6-(1-methylheptadec-1-yl)phenol,
2,4-dimethyl-6-(1-methyltridec-1-yl)phenol or mixtures thereof;
[0040] alkylthiomethylphenols, for example
2,4-dioctylthiomethyl-6-tert-bu- tylphenol,
2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-e-
thylphenol or 2,6-di-dodecylthiomethyl-4-nonylphenol;
[0041] hindered hydroquinones, for example
2,6-di-tert-butyl-4-methoxyphen- ol, 2,5-di-tert-butylhydroquinone,
2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,
2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,
3,5-di-tert-butyl-4-hydroxyanisole,
3,5-di-tert-butyl-4-hydroxyphenyl stearate or
bis-(3,5-di-tert-butyl-4-hy- droxyphenyl) adipate;
[0042] tocopherols, for example .alpha.-tocopherol,
.beta.-tocopherol, .gamma.-tocopherol, .delta.-tocopherol or
mixtures thereof (vitamin E);
[0043] hydroxylated thiodiphenyl ethers, for example
2,2'-thiobis(6-tert-butyl-4-methylphenol),
2,2'-thiobis(4-octylphenol),
4,4'-thiobis(6-tert-butyl-3-methylphenol),
4,4'-thiobis(6-tert-butyl-2-me- thylphenol),
4,4'-thiobis-(3,6-di-sec-amylphenol) or
4,4'-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide;
[0044] alkylidenebisphenols, for example
2,2'-methylenebis(6-tert-butyl-4-- methylphenol),
2,2'-methylenebis(6-tert-butyl-4-ethylphenol),
2,2'-methylenebis[4-methyl-6-(.alpha.-methylcyclohexyl)-phenol],
2,2'-methylenebis(4-methyl-6-cyclohexylphenol),
2,2'-methylenebis(6-nonyl- -4-methylphenol),
2,2'-methylenebis(4,6-di-tert-butylphenol),
2,2'-ethylidenebis(4,6-di-tert-butylphenol),
2,2'-ethylidenebis(6-tert-bu- tyl-4-isobutylphenol),
2,2'-methylenebis[6-.alpha.-methylbenzyl)-4-nonylph- enol],
2,2'-methylenebis[6-(.alpha.,.alpha.-dimethylbenzyl)-4-nonylphenol]-
, 4,4'-methylenebis(2,6-di-tert-butylphenol),
4,4'-methylenebis(6-tert-but- yl-2-methylphenol),
1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,
1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
1,1-bis(5-tert-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane-
, ethylene glycol
bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate],
bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene,
bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphe-
nyl]terephthalate, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane,
2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane,
2,2-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane
or
1,1,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane;
[0045] O-, N- and S-benzyl compounds, for example
3,5,3',5'-tetra-tert-but- yl-4,4'-dihydroxydi-benzyl ether,
octadecyl-4-hydroxy-3,5-dimethylbenzylme- rcaptoacetate,
tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate,
tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,
bis(4-tert-butyl-3-hydroxy--
2,6-dimethylbenzyl)dithioterephthalate,
bis(3,5-di-tert-butyl-4-hydroxy benzyl)sulfide or isooctyl
3,5-di-tert-butyl-4-hydroxybenzylmercaptoaceta- te;
[0046] hydroxybenzylated malonates, for example dioctadecyl
2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)-malonate, di-octadecyl
2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate,
di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malona-
te or
bis[4-(1,1,3,3-tetramethylbutyl)phenyl]2,2-bis(3,5-di-tert-butyl-4-h-
ydroxybenzyl)malonate;
[0047] aromatic hydroxybenzyl compounds, for example
1,3,5-tris-(3,5-di-tert-butyl-4-hydroxy-benzyl)-2,4,6-trimethylbenzene,
1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetrame-thylbenzene
or 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol;
[0048] triazine compounds, for example
2,4-bis(octylmercapto)-6-(3,5-di-te-
rt-butyl-4-hydroxyanilino)-1,3,5-triazine,
2-octylmercapto-4,6-bis(3,5-di--
tert-butyl-4-hydroxyanilino)-1,3,5-triazine,
2-octylmercapto-4,6-bis(3,5-d-
i-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,
2,4,6-tris-(3,5-di-tert-but- yl-4-hydroxyphenoxy)-1,2,3-triazine,
1,3,5-tris-(3,5-di-tert-butyl-4-hydro- xybenzyl)isocyanurate,
1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzy-
l)isocyanurate,
2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5--
triazine,
1,3,5-tris(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)-hexahydr-
o-1,3,5-triazine or
1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanura- te;
[0049] benzylphosphonates, for example dimethyl
2,5-di-tert-butyl-4-hydrox- ybenzylphosphonate,
diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl
3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl
5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate or the calcium
salt of the monoethyl ester of
3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid;
[0050] acylaminophenols, for example 4-hydroxylauranilide,
4-hydroxystearanilide or octyl
N-(3,5-di-tert-butyl-4-hydroxyphenyl)carba- mate;
[0051] esters of .beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)
propionic acid with mono- or polyhydric alcohols, e.g. with
methanol, ethanol, butanol, n-octanol, isooctanol (a mixture of
octanols), octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene
glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol,
diethylene glycol, triethylene glycol, pentaerythritol,
tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide,
3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,
trimethylolpropane or 4-hydroxymethyl-1-phospha-2,6,-
7-trioxabicyclo[2.2.2]octane;
[0052] esters of .beta.-(5-tert-butyl-4-hydroxy-3-methylphenyl)
propionic acid with mono- or polyhydric alcohols, e.g. with
methanol, ethanol, n-octanol, isooctanol (a mixture of octanols),
octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,
1,2-propanediol, neopentyl glycol, thiodiethylene glycol,
diethylene glycol, triethylene glycol, pentaerythritol,
tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide,
3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,
trimethylolpropane or 4-hydroxymethyl-1-phospha-2,6,-
7-trioxabicyclo[2.2.2]octane;
[0053] esters of .beta.-(3,5-dicyclohexyl-4-hydroxyphenyl)
propionic acid with mono- or polyhydric alcohols, e.g. with
methanol, ethanol, octanol, isooctanol (a mixture of octanols),
octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,
1,2-propanediol, neopentyl glycol, thiodiethylene glycol,
diethylene glycol, triethylene glycol, pentaerythritol,
tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox- -amide,
3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,
trimethylolpropane or
4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2- ]octane;
esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono-
or polyhydric alcohols, e.g. with methanol, ethanol, octanol,
isooctanol (a mixture of octanols), octadecanol, 1,6-hexanediol,
1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol,
thiodiethylene glycol, diethylene glycol, triethylene glycol,
pentaerythritol, tris(hydroxyethyl)isocyanurate,
N,N'-bis(hydroxyethyl)ox- amide, 3-thiaundecanol,
3-thiapentadecanol, trimethylhexanediol, trimethylolpropane or
4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2- ]octane;
and
[0054] amides of .beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)
propionic acid e.g.
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenedia-
mide,
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediam-
ide, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazide
or
N,N'-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxami-
de (Naugard.RTM. XL-1 supplied by Uniroyal).
[0055] For example, the antioxidant compound is diphenylamine, a
mixture of mono- and dialkylated
tert-butyl/tert-octyl-diphenylamines, a mixture of mono- and
dialkylated nonyldiphenylamines, phenylenediamine or
N,N'-di-sec-butyl-phenylenediamine.
[0056] The effective stabilizing amount of component c) is from
about 0.05 ppm to about 10,000 ppm, by weight, based on the weight
of the fuel composition. For example component c) is present from
about 0.1 ppm to about 1000 ppm, from about 0.2 ppm to about 100
ppm, or from about 0.5 ppm to about 25 ppm. For example, component
c) is present from about 0.05 ppm to about 1000 ppm, from about
0.05 ppm to about 100 ppm, or from about 0.05 ppm to about 25 ppm,
based on the entire fuel formulation. For instance, component c) is
present from about 0.1 ppm to about 10,000 ppm, from about 0.2 ppm
to about 10,000 ppm, or from about 0.5 ppm to about 10,000 ppm,
based on the weight of the entire fuel formulation.
[0057] The ratio of the stable nitroxides to the antioxidants is
for example from about 1:99 to about 95:5 parts by weight. For
example, the ratio of the stable nitroxides to the antioxidants by
weight is from about 1:10 to about 10:1, from about 1:5 to about
5:1, from about 1:3 to about 3:1, or about 1:1 parts by weight. The
ratio of the stable nitroxides to the antioxidants is for example
about 1:4 parts by weight.
[0058] The present stabilized compositions exhibit excellent
filterability. Accordingly, provided is a process for improving the
filterability and improving the cetane number of a diesel fuel,
which process comprises
[0059] adding to a diesel fuel with a cetane number less than or
equal to 50,
[0060] b) an effective amount of at least one compound selected
from the group consisting of the cetane improvers and
[0061] c) i) an effective stabilizing amount of at least one
compound selected from the group consisting of the stable nitroxide
compounds or
[0062] ii) an effective synergistic stabilizing amount of at least
one compound selected from the group consisting of the stable
nitroxide compounds and at least one antioxidant compound selected
from the group consisting of the aromatic amine antioxidants and
the hindered phenolic antioxidants.
[0063] Other traditional additives may also be present in the
compositions and processes of this invention. Other additives
include for example dispersants, for example
hydrocarbyl-substituted succinimides or succinamides and
hydrocarbylpolyamines; metallic based combustion improvers such as
ferocene, corrosion inhibitors, other antioxidants such as
amine-formaldehyde products, anti-foams, deodorants, anti-wear
agents, flow improvers, wax antisettling additives or other
operability improvers, cloud point depressants, friction modifiers,
solubilizers, anti-rust agents, detergents lubricants, other heat
stabilizers, and the like. Other additives may be present from
about 5 ppm to about 500 ppm by weight based on the weight of the
entire formulation.
[0064] The invention is illustrated by the following non-limiting
Example. Unless otherwise noted, parts and percentages are by
weight.
EXAMPLE 1
Diesel Fuel Filterability
[0065] Filterability is determined according to ASTM test method
D6468. A diesel fuel sample is heated under air to 150.degree. C.
for either 90 or 180 minutes. The fuel is then filtered, and the
amount of deposits on the filter paper is measured by reflectivity.
The more deposits trapped on the filter, the lower the reflectivity
of the filter pad. Too many deposits will clog filters in actual
use.
[0066] The table below demonstrates results with two different low
sulfur diesel fuels. Percent reflectance is measured on samples
heated to 150.degree. C. for 90 minutes. Levels are ppm based on
the fuel formulation.
1 Blend Percent Formulation 2-EHN Cmpd 1 Cmpd 2 Cmpd 3 1
Reflectance A 0 -- -- -- -- 94 B 1500 -- -- -- -- 69 D 1500 1.4 --
-- -- 74 E 1500 10.4 -- -- -- 78 F 0 -- -- -- -- 95 G 1500 -- -- --
-- 73 H 1500 -- 1.0 -- -- 74 I 1500 -- 10.0 -- -- 78 J 1500 -- --
1.0 -- 80 K 1500 -- -- 10.0 -- 84 L 1500 -- -- -- 1.0 79 M 1500 --
-- -- 10.0 84 2-EHN is 2-ethylhexyl nitrate cetane improver. Cmpd 1
is bis(1-oxyl-2,2,6,6-tetramethylpiperidi- n-4-yl) sebacate. Cmpd 2
is 1-oxyl-4-hydroxy-2,2,6,6-tetramethylpi- peridine. Cmpd 3 is
1-oxyl-4-n-propoxy-2,2,6,6-tetramethylpiperidi- ne.
[0067] Blend 1 is 14% Cmpd 1, 56% by weight mixture of mono- and
dialkylated tert-butyl/tert-octyl-diphenylamines, 30% inert
aromatic solvent (by weight).
[0068] Formulations A-E are with Diesel Fuel 1. Formulations F-M
are with Diesel Fuel 2. The two fuels are within ASTM D975
specifications (diesel fuel specifications) according to the
present invention.
[0069] It is seen that the cetane improver significantly reduces
the filterability of the diesel fuel. Even at a level of 1 ppm of
added stable nitroxide compound, there is a marked decrease in
precipitate as indicated by a measurable increase in filter pad
reflectance. Thus, with the use of the nitroxide alone or in
combination with antioxidants, there will be a reduced tendency for
diesel fuel to form insoluble material that could plug fuel filters
and lines.
* * * * *