Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF DEHAZING HYDROCARBON FUELS
Backaround of the Invention
This invention relates to the dehazing of
hydrocar~on fuels. In particular, the invention relates
to chemical means for dehazing such fuels.
In the commercial transportation and storage of
hydrocarbon fuels such as gasoline, diesel fuel, jet
fuel, turbine oils, and fuel oils, the fuel sometimes
comes in contact with water. Often the result is an
emulsion of water in the fuel which gives the fuel a
cloudy appearance referred to as "haze". Because haze in
a fuel is associated with low grade, contaminated, or
degraded fuels, it is commercially important to break the
emulsion and "dehaze" the fuel.
Various chemical means such as oxyalkylated phenol
formaldehyde resins are used for dehazing fuels. One
limitation is that chemical dehazers do not have
universal application. Whether due to innate differences
in the fuel itself, various contaminates, decomposition
products, or performance additives, dehazers that work
well for one fuel will perform only marginally in
another. In general, a specific hazy fuel is evaluated
by subjecting it to a battery of dehazing agents and the
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best performer is then selected for full scale use. In
view of the variety of fuels and conditions which
contribute to haze formation, an additional chemical
dehazer would be an advance to the art of fuel dehazing.
US 4,326,987 (Hendricks - Petrolite, 1982) discloses
the reaction product of (a) an alkenyl or alkyl succinic
acid or anhydride with (b) an alkylether diamine; and the
use of that reaction product as a corrosion inhibitor for
hydrocarbon fuels.
Summary of the Invention
Briefly, the invention is a method of dehazing a
hazy hydrocarbon fuel, by contacting the fuel with the
reaction product of (a) an alkenyl or alkyl succinic acid
or anhydride, and (b) an alkylether diamine.
In another respect, the invention i8 the dehazed
fuel resulting from the above method.
The method of the invention is particularly
economical and convenient to carry out. The fuels of the
invention are relatively free of haze and have a
desirable physical appearance.
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Detailed Description of the Invention
In this specification and claims, numerical ranges
are not critical unless otherwise stated. That is, the
numerical values may be read as if they were prefaced
with the word "about" or "substantially".
A first component of the invention is an alkenyl or
alkyl succinic acid or anhydride. These compounds have
the general formulas:
O O
R CH- C R CH - C
\ I \
I OH
CH2 -ICl I OH
O CH2 - C
(anhydride) O
(acid)
wherein R is an alkenyl or alkyl radical having at least
2 carbon atoms.
R may be straight or branched. If unsaturated, R
may be saturated by addition of hydrogen, sulfur, or a
halogen, but unsaturation is preferred. R must have at
least 2 carbon atoms and desirably has 2 to 32, more
desirably 4 to 28, preferably 6 to 24, more preferably 8
to 18, and more preferably 10 to 14 carbon atoms.
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Although the anhydride form may be used, the acid is
preferred.
Examples of suitable succinic acid or anhydride
compounds include ethenyl succinic anhydrides; ethenyl
succinic acid; ethyl succinic anhydride; propenyl
succinic anhydride; sulfurized propenyl succinic
anhydride; butenyl succinic acid; 2-methyl-butenyl
succinic anhydride; 1,2-dichloropentyl succinic
anhydride; hexenyl succinic anhydride; hexyl succinic
acid; sulfurized 3-methyl-pentenyl succinic anhydride;
2,3-dimethylbutenyl succinic anhydride;
3,3-dimethylbutenyl succinic acid;
1,2-dibromo-2-ethylbutyl succinic acid, heptenyl succinic
anhydride; 1,2-diodooctyl succinic acid; octenyl succinic
anhydride; 2-methylheptenyl succinic anhydride;
4-ethylhexenyl succinic acid; 2-isopropylpentyl succinic
anhydride; nonenyl succinic anhydride; 2-propylhexenyl
succinic anhydride; decenyl succinic acid; decenyl
succinic anhydride; 5-methyl-2-isopropylhexenyl succinic
anhydride; 1,2-dibromo-2-ethyloctenyl succinic anhydride;
decyl succinic anhydride; undecenyl succinic anhydride;
1,2-dichloro-undecyl succinic acid; 3-ethyl-2-t-
butylpentenyl succinic anhydride; dodecenyl succinic
anhydride; dodecenyl succinic acid; 2-propylnonenyl
succinic anhydride; 3-butyloctenyl succinic anhydride;
tridecenyl succinic anhydride; tetradecenyl succinic
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anhydride; hexadecenyl succinic anhydride; sulfurized
octadecenyl succinic acid; octadecyl succinic anhydride;
1,2-dibromo-2-methylpentadecenyl succinic anhydride,
8-propylpentadecyl succinic anhydride; eicosenyl succinic
anhydride; 1,2-dichloro-2-methylnona decenyl succinic
anhydride; 2-octyldodecenyl succinic acid;
1,2-diiodotetracosenyl succinic anhydride; hexacosenyl
succinic acid; hexacosenyl succinic anhydride; and
hentriacontenyl succinic anhydride. The preferred
compound is tetrapropenyl succinic acid
(dodecenylsuccinic acid).
The methods of preparing the alkenyl and alkyl
succinic acids and anhydrides are well known to those
lS skilled in the art. For instance, the most feasible
method of preparing alkenyl succinic anhydrides is by the
reaction of an olefin with maleic anhydride. Since
relatively pure olefins are difficult to obtain, and when
obtainable are often too expensive for commercial use,
alkenyl succinic anhydrides are usually prepared as
mixtures by reacting mixtures of olefins with maleic
anhydride.
A second component of the invention is an alkyether
diamine, preferably having the formula
Rl~R2NHR3NH2
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wherein Rl is a Cl to C18, desirably C4 to C14,
preferably C6 to C12, and more preferably C8 to C10 alkyl
moiety, and R2 and R3 are each independently C2 to C12,
desirably C2 to C10, preferably C2 to C5, and more
preferably C3 alkyl moieties. The preferred alkylether
diamine is
CH3(cH2)7-9o(cH2)3NH(cH2)3NH2
The reaction products are prepared by mixing the
components together at ambient temperature. Since the
reaction is exothermic, cooling may be desirable in
larger batches.
The molar ratio of acid/anhydride to amine is
generally 1:1 to 1~:1, desirably 1:1 to 8:1, preferably
1.5:1 to 6:1, most preferably 2:1 to 4:1.
Since the reaction products are generally solids,
they are conveniently used in the form of solutions.
Because of their low price and good solution
characteristics, aromatic hydrocarbons are the preferred
solvents.
Further details concerning the reactants, the
reaction methods, and the reaction products may be found
in the aforementioned US 4,326,987, which is incorporated
herein by reference.
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J
The reaction products are useful to remove haze from
hydrocarbon fuels such as gasoline, diesel fuel, jet
fuel, turbine oils, and fuel oils. The haze is removed
by contacting the hazy fuel with a dehazing amount of the
reaction product. By "dehazing amount" is meant an
amount that will measurably reduce the amount of haze
present. Generally, the reaction products will be used
at 1 to 1,000 ppm (parts per million), desirably 5 to 800
ppm, preferably 10 to 500 ppm, and more preferably 30 to
300 ppm.
The contacting may be accomplished by simply pouring
the reaction product into the fuel. However, it is
greatly preferred that the containing include thorough
mixing, such as by shaking, pumping, or stirring.
As the dehazing takes place, droplets of water will
coalesce and fall to the bottom of the fuel, allowing the
water and fuel to be separated.
Importantly, the compounds useful in the invention
will dehaze not only pure fuels, but also fuels
containing additives such as pour point depressants (cold
flow improvers). The invention is applicable to a wide
variety of hydrocarbon fuels under a wide variety of
conditions.
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The invention will be further explained in the
following examples. In the examples, all parts and
percentages are by weight unless otherwise specified.
Example 1
99 ml of fuel oil (furnace oil) containing 70 ppm
(volume) of a chlorine-containing pour point depressant
(sold as TOLAD~ T-35 by Petrolite Corporation) and 1.O ml
of tap water (pH = 9.0) were emulsified by mixing for 60
seconds at high speed in a stainless steel malt cup on a
Hamilton Beach mixer (Model 936) equipped with a fly leaf
agitator. The emulsified fuel, now having a distinctly
hazy appearance, was transferred to a series of glass
containers. Various amounts of the reaction product of a
3:1 (molar ratio) mixture of dodecenylsuccinic acid and
CH3(cH2)7-so(cH2)3NH(cH2)3NH2~ in the form of a 29.0%
solution in aromatic hydrocarbons (identified as compound
"I"), were added, followed by shaking for 2 minutes on a
shaking machine set at 130 shakes per minute. The degree
of haze was then monitored at various intervals by
measuring light transmittance with a Brinkmann
colorimeter tModel PC-800) equipped with an 830 nm filter
and a stainless steel probe having a 20 nm path length.
The results are reported in Table I.
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Comparative Example 1
Following the procedure of Example 1, the evaluation
was repeated with an oxyalkylated alkylphenolic resin tin
a 33.5% active solution) commercial dehazer, sold as
TOLAD T-500 by Petrolite Corporation (identified as
compound C-1); an oxyalkylated alkylphenolic resin and a
fatty amine-aryl quaternary (in a 37.7% active solution),
emulsion preventive, sold as AR-35 by Petrolite
Corporation (identified as compound C-2); and an
oxyalkylated alkylphenolic resin and polyamines (in a
43.9% active solution) demulsifier, sold as Experimental
Product EXI-382 by Petrolite Corporation (identified as
compound C-3). The results are shown in Table I.
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Example 2
and
Comparative Example 2
The procedure of Example 1 and Comparative Example 1
were followed except that instead of tap water, a buffer
solution of pH 4 (Fisher Scientific S0-B-101),
pH 7 (Fisher Scientific S0-B--107), or pH 10 (Fisher
Scientific S0-B-115) was used. Also, in some tests at
pH = 7, the pour point depressant was not present in the
fuel oil. The data are shown in Table II.
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