Note: Descriptions are shown in the official language in which they were submitted.
2~5'~
.
DIESEL FUEL COMPOSITION
Diesel engines operate by compression ignition.
They have compression ratios in the range of 14:1 to
17:1 or higher and for that reason obtain more useful
5 work from a given amount of fuel compared to an Otto
cycle engine. Historically, diesel engines have been
operated on a petroleum-derived liquid hydrocarbon fuel
boiling in the range of about 300-750F (149-399C.).
Recently, because of dwindling petroleum reserves,
LO alcohol and alcohol-hydrocarbon blends have been studied
for use as diesel fuel.
One major factor in diesel fuel quality is octane
number. Octane number is related to ignition delay
after the fuel is injected into the combustion chamber.
15 If ignition delays too long, the amount of fuel in lie
chamber increases and upon ignition results in a rough
running engine and increased smoke. A short ignition
delay results in smooth engine operation and decreases
smoke. Commercial petroleum diesel fuels generally have
20 a octane number of about 40-55. Alcohols have a much
lower octane value and require the addition of A octane
improver for successful engine operation.
Through the years, many types of additives have
been used to raise the octane number of diesel fuel.
, I' .
.
' _
.... . . ..
1'22~
These include peroxides, nitrites, nitrates, nutrias-
carbamates, and the like. Alkyd nitrates such as Amy
nitrate, Huxley nitrate and mixed octal nitrates have
been used commercially with good results.
The present invention provides an increased
octane rating for a diesel fuel, either hydrocarbon,
alcohol or mixed, by the addition of a small but effective
amount of a primary aliphatic nitrate, or a heterocyclic
aliphatic nitrate or dinitrate compound.
A preferred embodiment of the invention is liquid
fuel adapted for use in a diesel engine, said fuel being
selected from the group consisting of liquid hydrocarbons
of the diesel boiling range, alcohols, and mixtures
thereof, said fuel containing a octane increasing amount
of a tetrahydropyranol nitrate.
Representative examples of these additives in-
elude:
4-methyltetrahydro-2H-pyran-3-ol nitrate
4-ethyltetrahydro-2~1-pyran-3-ol nitrate
tetrahydropyran-2-ol nitrate
3-ethyltetrahydro-3H-pyran-4-ol nitrate
3-dodecyltetrahydro-3H-pyran-4-ol nitrate
3-methyl-tetrahydropyran-2-ol nitrate
5-chlorotetrahydro-211-pyran-3-ol nitrate
4-bromotetrahydro-211-pyran-3-ol nitrate
4-methyl-5-chlorotetrahydro-21~-pyran-3-ol nitrate,
and the like. A more preferred class of perineal nitrates
include compounds having the structure:
-- 2 --
mob/ by - -
! - .
. .
~2~8854
R"
R ONE
wherein R' and R" are independently selected from the
group consisting of hydrogen, alkyd containing 1-20
carbon atoms, cycloalkyl containing 5-8 carbon atoms,
alkenyl containing 2-20 carbon atoms, aureole containing
6-12 carbon atoms and aralkyl containing 7-12 carbon
atoms. The remaining carbon bonds are hydrogen substituted.
The present invention also provides a octane increasing
additive selected from l-alkyl-piperidinol nitrate and the
perineal nitrates of the above structure.
Doyle
1;~28~3~5~
Representative examples of this preferred
embodiment include:
4,5-dimethyltetrahydro-2H-pyran-3-ol nitrate
4-octadecyltetrahydro-2H-pyran-3-ol nitrate
4-eicosyltetrahydro-2H-pyran-3-ol nitrate
4-allyltetrabydro-2H-pyran-3-ol nitrate
5-hexadecenyltetrahydro-2H-pyran-3-ol nitrate
S-cyclopentyltetrahydro-2H-pyran-3-ol nitrate
5-cyclohexyltetrahydro-2H-pyran-3-ol nitrate
4-cyclooctyltetrahydro-2H-pyran-3-ol nitrate
4-methyl-5-phenyltetrahydro-2H-pyran-3-ol nitrate
5-benzyltetrahydro-2H-pyran-3-ol nitrate
5-(alpha,alpha-dimethylbenzyl~tetrahydro-2H-
perineal nitrate
5-(4-sec-pentylbenzyl)tetrahydro-2H-pyran-3-ol
nitrate, and the like.
Tube most preferred tetrahydropyranol nitrate
octane improver is tetrahydro-2H-pyran-3-ol nitrate.
The following example shows the preparation of a
20 tetrahydropyranol nitrate by reaction of the cores-
pounding hydroxy compound with mixed nitric acid-acetic
android
EXAMPLE 1
In a reaction vessel was placed 50 ml acetic
25 anbydride. While cooling, 14 ml of 90 percent fuming
nitric acid was added. Following this, 25 g. of
1~2885d~
tetrahydro-2H-pyran-3-ol was added drops at -8 to
-10C. over a one hour period. Stirring was continued
for 1.5 hours at -10C. The mixture was then allowed
to warm to room temperature and then poured into an ice-
5 water mixture. Tube organic phase settled and was separated. The organic phase was diluted with metbylene
chloride and also washed with aqueous Nikko and dried
over McCoy. The solvent was removed under vacuum
leaving 24.04 g. of tetrahydro-2H-pyran-3-ol nitrate.
10 The structure was confirmed by IT and NOR analysis.
Other tetrahydropyranol nitrates can be made
following the above general procedure by substituting
other tetrahydropyranols.
Another preferred embodiment of the invention is
15 liquid fuel adapted for use in a diesel engine, said
fuel being selected from the group consisting of liquid
hydrocarbons of the diesel boiling range, alcohols and
mixtures thereof, said fuel containing a octane
increasing amount of a tetrahydrofurandiol dinitrate
20 octane improver.
The tetrahydrofurandiol dinitrates have the
structure
NOAH} N2
.. _ .... ,.. . . " .
~22~3~5~
The remaining valences are bonded to hydrogen or can be
substituted with other groups such as alkyd, aureole, cycle-
alkyd, aralkyl, halogen and the like.
Representative examples of such compounds are
~,5-dimethyltetrahydro-3,4-furandiol dinitrate
2-isooctyltetrahydro-3,4-furandiol dinitrate
2-eicosyltetrahydro-3,4-furandiol dinitrate
2-phenyltetrahydro-3,4-furandiol dinitrate
2-benzyltetrahydro-3,4-furandiol dinitrate
lo 2-(alpha-methylbenzyl)tetrahydro-3,4-furandiol
dinitrate
2-chlorotetrahydro-3,4-furandiol dinitrate
2-bromotetrahydro-3,4-furandiol dinitrate
2-cyclohexyltetrahydro-3,4-furandiol dinitrate
2-(4-isobutylphenyl)tetrahydro-3,4-furandiol
dinitrate and the like.
The most preferred tetrahydrofurandiol dinitrate
octane improver is tetrahydro-3,4-furandiol dinitrate.
The following example shows a method for making
20 the additives by the nitration of the appropriate
tetrahydrofurandiol using mixed nitric-sulfuric acid.
Example 2
In a reaction vessel was placed a mixture of 18.7
ml 70 percent nitric acid, 28 ml concentrated sulfuric
25 acid and 0.23 g. urea. This was stirred and cooled to
-10C. at which time an equal volume mixture of
ethylene chloride and tetrahydro-3,4-furandiol (25 g.
_ 6 --
.. . ... .. .. . . . .,.
~2~854~
0.24 mole) was added drops. After one-third of this
solution had been added, an additional 18.6 ml 70
percent nitric acid, 27 ml concentrated sulfuric acid
and 0.23 g. urea was added. While stirring at about
-10C., the remaining solution was added drops.
Total addition time was 1.5 hours. The mixture was
stirred an additional 30 minutes at -10C. and then
poured into an ice-water mixture. The organic layer was
separated and the aqueous layer extracted twice with 300
10 ml portions of ethylene chloride. The ethylene
chloride solutions were all combined and washed with
aqueous sodium bicarbonate and dried over McCoy. The
filtered solution was diluted further wit 46.5 g.
n-cetane and the ethylene chloride removed under
vacuum. The purpose of the added octane was to avoid
handling the pure tetrahydro-3,4-furandiol dinitrate
because of a possible explosion hazard. However, the
dinitrate was not soluble in n-cetane and two layers
formed. The lower layer was confirmed by infrared and
NOR analysis to be tetrahydro-3,4-furandiol dinitrate.
The dinitrate layer (16.57 g.) was diluted with 42.98 g.
ethylene chloride and later a portion was added to
diesel fuel for testing. The presence of tube delineate
was a precaution and the use of a delineate is not
essential to the invention.
Another preferred embodiment of the invention is
liquid fuel adapted for use in a diesel engine, said
..... .. . . . .
aye
fuel being selected from the group consisting of liquid
hydrocflrbons of the diesel boiling range, fllcohols and
mixtures thereof, said fuel containing a octane number
increasing amount of a l-alkylpiperidinol nitrate.
The l-alkylpiperidinol nitrate may be substituted
in the heterocyclic ring by groups in addition to the
nitrate group. For example, the ring substituent can
include alkyd (e.g., methyl, ethyl, n-propyl, dodecyl
and the like), aureole (e.g., phenol, toll and the like),
10 halo (e.g., sheller, broom and the like), alkoxy (e.g.,
methoxy, ethics, propoxy, and the like), aralkyl (e.g.,
bouncily, alpha-methylbenzyl and the like), cycloalkyl
(e.g., cyclopentyl, cyclohexyl, and the like) and
alkenyl (e.g., ally, octenyl, dodecenyl and the like.
the l-alkyl or N-~lkyl group can be any alkyd
such as those containing 1-20 carbon atoms. These
include methyl, ethyl, n-propyl, isobutyl, n-hexyl,
2-ethylhexyl, octadecyl, eicosyl, and the like. More
preferably, the l-alkyl grOlJp is a lower alkyd contain-
20 in about 1-8 carbon atoms, still more preferably about
1-4 carbon atoms.
The nitrate aster group is preferably in the 3-
or 4- positions. In other words, highly preferred
embodiments are l-alkyl-3-piperidinol nitrflte nod
25 1-alkyl-4-pipcridinol niLrnte. Yost preferably, the
l-alkyl group is methyl such thwart the most preferred
.... . . . .
I
.
additives are l-methyl-3-piperidinol nitrate and
l-methyl-4-piperidino] nitrate, which are 'relieved to be
novel compounds. They have the structure
ONE
S I ONE Jo
SHEA SHEA
The foregoing octane number improving additives
lo can be made by reacting the appropriate l-alkyl
piperidinol with mixed nitric-sulfuric acid at low
temperatures, e.g., -15 to 0C.
EXAMPLE 3
In a reaction vessel was placed 27 g. (0;3 mole)
15 70 percent nitric acid. This was stirred and 86.5 g. 98
percent sulfuric acid was added slowly at -16 to
-10C. Then, 0.2 I. of urea was added. To this was
added drops 23.5 g. (0.2 mole) 4-hydroxy-N-methyl
piperidine also named l-methyl-4-piperidinol over a 48
20 minute period at -9 to -12C. The resulting mix-
lure was poured into an ice-water mixture. The acidic
aqueous solution was neutralized with sodium coronet
(pi 9.0) and extracted twice with deathly ether. the
extracts were combined and dried over an hydrous
25 Noah. The ether was distilled out under vacuum
~2~l3854
(30C. per 30 mm Hug absolve leaving 11.78 g. of yellow
oil. Infrared confirmed it as 1-methyl-4-
piperidinol nitrate.
The aqueous phase was extracted again with three
S portions of ethyl acetate. The extract was dried as
before and the ethyl acetate distilled out under vacuum
leaving 11.47 g. of product. This was identified by
infrared to be the same as the other extracted product.
Both products were combined.
EXAMPLE 4
In a reaction vessel was placed 85.6 g. concern-
treated sulfuric acid. This was stirred at -20C. and
19.1 ml (0.3 mole) concentrated nitric (70 percent) was
added at -11.6 to -20C. Then, 0.2 g. of urea was
15 added followed by 23.5 g. (0.2 mole) 3-hydroxy-N methyl
piperidine at -9 to -12C. over a 46 minute period.
The reaction mixture was poured into an ice-water mix-
lure (150 ml). The aqueous solution was neutralized
with sodium carbonate and extracted as in Example 4,
20 first wit deathly ether (3 x 100 ml) and then with
ethyl acetate (2 x 100 ml plus 1 x 150 ml). Both
extracts were dried over an hydrous sodium sulfate and
the solvents were distilled out under vacuum. The ether
extract gave 19.49 g. of residuum liquid which was
25 identified by infrared as 1-methyl-3-piperidinol
nitrate. The 1.21 g. residual from the ethyl acetate
-- 10 -
... .. .
~l2;~:~385~
,
extract contained nitrate but a strong hydroxyl bond
remained so it was discarded
Other l-alkylpiperidinol nitrates can be made
following the above general procedure by substituting
5 other l-alkylpiperidinol starting materials.
The octane increase caused by the present
additives was measured in comparison with that caused
by a commercial octane improver, isooctyl nitrate, using
a standard octane engine. the fuel used was a blend of
10 46 octane number diesel fuel and 28 octane number light
cycle oil resulting in a 38 octane number blend diesel
fuel. The results at various concentrations are shown
in the following table.
l-Methyl-3- 1-Methyl-4-
lo Concentration Isooctyl Piperidinol Piperidinol
(wt. %) Nitrate Nitrate Nitrate
None 38 38 38
0.05 39.3 40.46 39.44
Owe 40.5 42.41 40.66
20 0.15 41.8 43.17 43.32 .
Other conventional additives may be included in tube
diesel fuel including antioxidant, pour point
depressants, cold filter plugging inhibitors,
detergents, rust inhibitors and the like, including
25 other octane improvers.
- 11 --
2~3854c
Another preferred embodiment of the invention is
a liquid fuel adapted for use in a diesel engine, said
fuel being selected from the group consisting of liquid
hydrocarbons of the diesel boiling range, alcohols and
mixtures thereof, said fuel containing a octane number
increasing amount of a fuel soluble 4-morpboline alkanol
nitrate. Such compounds contain in their structure the
group
I
J
N
C H ON
wherein n is an integer from 1 to about 20, more prey-
drably about 1-4. The morpholine heterocyclic ring may
be substituted with any of a broad range of substituents
15 as long as they do not render the compound insoluble in
diesel fuel.
A still more preferred group of additives have
the structure
N
RYAN
1228~354
wherein R is a diva lent hydrocarbon group containing
1-20 carbon atoms, and R' and R" are independently
selected from the group consisting of hydrogen, alkyds
containing 1-20 carbon atoms, cycloalkyl containing S-8
5 carbon atoms, alkenyl containing 2-20 carbon atoms, aureole
containing 6-12 carbon atoms, and aralkyl containing
7-12 carbon atoms.
Representative examples of these additives are:
4-(2-methylmorpholine) ethanol nitrate
4-(3-isooctylmorpholine) ethanol nitrate
4-(3-eicosylmorpholine) buttonhole nitrate
4-(3-cyclopentylmorpholine hexanol nitrate
4-(2-cyclohexylmorpholine) octanol nitrate
4-(2-cyclooctylmorpholine) dodecanol nitrate
lo 4-(2-propenylmorpholine) propanol nitrate
4-(3-dodecenylmorpholine) ethanol nitrate
4-(3-eicosenylmorpholine ethanol nitrate
4-(2-phenylmorpholine) ethanol nitrate
4-(3-naphthylmorpholine) buttonhole nitrate
4-(3-benzylmorpholine) buttonhole nitrate
4-[2-(alpha-methylbenzyl)morpholine] ethanol
nitrate
4-[3-(4-isohexylphenyl)morpboline~ethanol nitrate
and the like.
In a more preferred embodiment, both R' and R" in
the above structure are hydrogen and R is a diva lent
hydrocarbon group containing about 1-4 carbon atoms.
12288~
These compounds include:
4-morpholine ethanol nitrate
4-morpholine-(2-methylethanol) nitrate
4-morpholine methanol nitrate
4-morpholine buttonhole nitrate
The most preferred 4-morpholine alkanol nitrate
additive is 4-morpholine ethanol nitrate which has the
structure
' .
0 N - CH2CH2 - ONE
10 This preferred compound is reported at Bull. Sock Cbem.
, p. 470 (1944).
The additives can readily be prepared by
nitration of tube corresponding 4-morpholine alkanol
compound by standard procedures suck as by use of mixed
15 sulfuric-nitric acid or acetic anhydride-nitric acid.
The 4-morpboline alkanol is added to the rapidly stirred
mixed acid at low temperatures such as -20 to 10C.,
more preferably, about -15C. to 0C.
EXAMPLE S
In a reaction vessel was placed 28 ml concern-
treated sulfuric acid. To this was added 25 g. ox
N-ethanol morpholine to form the ammonium salt. In if
second vessel was placed a solution of 14.8 ml concern-
treated nitric acid and 22 ml concentrated sulfuric
- 14 -
. .
`
~2~88~
acid. The mixed acid was cooled to -14C. The above
N-ethanol morpholine salt was added to this over a
two-hour period. The temperature was allowed to rise to
the 6.6-7.2C. range. The reaction mixture was
5 stirred an additional 30 minutes and then poured into an
ice-water mixture. The aqueous solution was neutralized
to pi 8 using sodium carbonate. An upper organic layer
formed. The entire mixture was extracted twice with 150
ml portions of deathly ether. The ether extract was
10 dried over magnesium sulfate and the ether removed under
vacuum. The product formed a viscous gel which was
soluble in diesel fuel. Tube product was identified by
IT and NOR as 4-morpholine ethanol nitrate.
Other 4-morpholine alkanol nitrate esters can be
15 made by following the above general procedure.
- 15 -
.
- ..
~2;~3854
the amount of octane improver added depends on
the type of fuel being used, the initial octane value,
and the amount of octane number increase desired.
Alcohol fuels such as methanol, ethanol, isopropanol,
isobutanol, hexanol, and the like, have very low octane
values and large amounts of octane improvers are
required. A useful range in which to operate is about
5-25 weight percent octane improver.
Blends of alcohol and petroleum-derived diesel
lo fuel brave higher octane values and require less octane
improver. A useful range is about Lowe weight percent.
Petroleum-derived distillate fuels in the diesel
boiling range require only small amounts of octane
improver to achieve a significant increase in octane
number. Such fuels without any octane improver
generally have octane numbers in the range of about
25-60. Octane numbers in the range of 25-35 ore
considered low and those in the range of 50-60 arc
- 16 -
~2~8~54
considered top grade diesel fuels. Diesel fuels in the
35-50 mid-range are most common. An object of the
invention is to upgrade the low octane number fuels at
least into the mid-range and to increase the octane
5 value of the mid-range fuels into the upper portion of
the mid-range (e.g., 45-50) or even into the premium
range above 50. It has been found that highly
beneficial results can be achieved using as little as
0.05 weight percent of the present additive. Accord-
10 tingly, a useful concentration range in petroleum derived diesel fuel is about 0.01-5 weight percent and more
preferably about OOZE weight percent.
- 17 -
_
1~28 !354
The octane increase caused by the tetrahydro-
perineal nitrate additive was measured in comparison with
that caused by a commercial sweated improver, isooctyl
nitrate, using a standard octane engine. The fuel used
was 3 blend of 46 octane diesel fuel and 28 octane light
cycle oil giving a 38 octane No. diesel fuel. Tube
results at various concentrations of tetrabydro-2H-pyran
oily nitrate and isooctyl nitrate are shown in the
following table.
Tetrahydro-3H-pyran-
Isooct~l Nitrate oily Nitrate
Concentration ON ON _
None 38 - 38
0.15 41.64, 41.65 42.24, 42.38
Tube octane increase caused by the tetrahydro-
furandiol dinitrate additive measured using a standard
octane engine under the conditions described immediately
above is shown in the following table.
- 18 -
12;~8854
Tetrahydro 3,4-~urandiol
Concentration Dinitrate
None 38
0.1S wt. percent 40.50, 40.57
The octane increase caused by the 4-morpholine
5 alkanol nitrate as tested under the conditions noted above
is shown in the following table.
- Isooctyl4-Morpbone ethanol
Concentration Nitrate Nitrate
None 38.0 38.0
lo 0.05 39.3 40.07
0.1 40.5 41.01
0.15 41.8 41.1g
These results show that the new additives are
very effective in raising the octane number of diesel
15 fuel.
Other conventional additives may be included in
the diesel fuel including antioxidant, pour point
depressants, cold flow improvers, cold filter plugging
inhibitors, detergents, rust inhibitors and the like,
20 including other octane improvers.
- 19 -
