U.S. patent application number 10/480561 was filed with the patent office on 2004-09-30 for process for preparing a fuel additive and the additive.
Invention is credited to Ahonen, Heikki, Fredrikson, Martti.
Application Number | 20040187379 10/480561 |
Document ID | / |
Family ID | 8561368 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040187379 |
Kind Code |
A1 |
Fredrikson, Martti ; et
al. |
September 30, 2004 |
Process for preparing a fuel additive and the additive
Abstract
The invention relates to a method for manufacturing a fuel
additive and to the additive. It relates particularly to a
lubricant additive that is highly suitable for use as an additive
in connection with diesel engines. According to the method,
saturated fatty acids with a high melting point are separated by
cooling from a fatty-acid mixture, the said fraction of fatty acids
with a high melting point being esterified and/or aminated to form
a mixture of more than three esters and/or amines and the mixture
thus obtained being re-mixed with that part of the original
fatty-acid mixture from which the fatty acids with a high melting
point were separated and the necessary amount of this
last-mentioned mixture being mixed with fuel to form a lubricant.
The separation of the saturated fatty acids with a high melting
point takes place by passing the mixture through a cooling
heat-transfer surface, to which the fatty acids adhere, and by
removing the fatty acids from the surface by raising its
temperature.
Inventors: |
Fredrikson, Martti; (Rauma,
FI) ; Ahonen, Heikki; (Ritvala, FI) |
Correspondence
Address: |
JOEL D. SKINNER, JR.
SKINNER AND ASSOCIATES
212 COMMERCIAL ST.
HUDSON
WI
54016
US
|
Family ID: |
8561368 |
Appl. No.: |
10/480561 |
Filed: |
May 5, 2004 |
PCT Filed: |
June 10, 2002 |
PCT NO: |
PCT/FI02/00501 |
Current U.S.
Class: |
44/401 |
Current CPC
Class: |
C10L 1/18 20130101; C10L
1/14 20130101; C10L 10/04 20130101; C10L 1/221 20130101; C10L
1/1881 20130101; C10L 1/19 20130101 |
Class at
Publication: |
044/401 |
International
Class: |
C10L 001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2001 |
FI |
20011214 |
Claims
1. A method for manufacturing fatty-acid compounds for use as a
lubricant fuel additive, characterized in that saturated fatty
acids with a high melting point are separated from a fatty-acid
mixture by cooling, the fraction of the fatty acids with a high
melting point is esterfied and/or aminated to form a mixture of
more than three esters and/or amines and the mixture thus created
is re-mixed with that part of the original fatty-acid mixture, from
which the fatty acids with a high melting point were separated, and
mixed with the necessary amount of this last-mentioned mixture to
form a fuel lubricant.
2. A method according to claim 1, characterized in that the fatty
acids with a high melting point are separate from the fatty-acid
mixture by passing the mixture through a cooling heat-transfer
surface and that the fatty acids adhering to the cold surface are
removed by raising its temperature.
3. A method according to claim 1, characterized in that the
fraction of saturated fatty acids with a high melting point is
esterified using a mixture of several alcohols.
4. A method according to claim 3, characterized in that the
esterification takes place using fusel oil.
5. A method according to claim 4, characterized in that the
esterification takes place using a fusel oil in which there is
water, the salts dissolved in which being removed by cooling the
said fusel oil to a temperature of less than 0.degree. C.,
particularly to a temperature of -10--25.degree. C. and removing
the separated water phase.
6. A method according to claims 4, characterized in that the fusel
oil is distilled prior to the esterification treatment.
7. A method according to claim 1, characterized in that the
fraction of fatty acids with a high melting point is aminated,
particularly using diamines or amino-alcohols and/or lactarns.
8. A method according to claim 7, characterized in that the
amination takes place at a temperature of 130-150.degree. C. and in
the presence of an acid catalyst while mixing for at least 1
hour.
9. A method according to claim 7, characterized in that the
amination takes place using N,N-dialkylamines.
10. A method according to any of the above claims, characterized in
that the saturated fatty acids are treated by both esterification
and amination, either together or separately, and that the products
obtained are mixed with the unsaturated fatty acids that remain
from the fatty-acid mixture, from which the saturated fatty acids
were separated.
11. A lubricant fuel additive comprising fatty-acid compounds,
characterized in that it includes esterified and/or aminated
saturated fatty acids with a high melting point and unsaturated
fatty acids with a low melting point.
12. An additive according to claim 11, characterized in that the
additive contains esters of saturated fatty acids with a high
melting point together with several alcohols.
13. An additive according to claim 11, characterized in that the
additive is formed of essentially the fatty acids of tall oil, the
saturated fatty acids of which are esterified/aminated.
Description
[0001] The present invention relates to a method for manufacturing
a fuel additive and the additive. The invention particularly
relates to a lubricating additive, which is especially suitable for
use as an additive used with diesel engines.
[0002] The continual increase in the prices of fuels, particularly
fuels for combustion engines, and the tightening of environmental
regulations have lead to numerous proposed and actual improvements
in both engines and in fuels.
[0003] In automotive engines, engines based on the Diesel cycle are
gaining ground over petrol engines, due to the greater thermal
efficiency of diesel engines. In addition to their existing
efficiency, based on a high compression ratio, their operation has
been further improved by using fuel injection into the combustion
chamber.
[0004] At the same time as environmental demands have led to a
great reduction in the sulphur content of these fuels, polyaromatic
and other closed-chain compounds, which as such have excellent
lubricating properties for high-pressure fuel-injection equipment,
have been removed from the fuel along with the sulphur.
[0005] Fatty acids have proven to be good additives for fuel,
particularly diesel fuel. However, fatty acids have the well-known
drawback that they crystallize or that substances such as stearic
acid and arachid acid crystallize easily out of them, in other
words, fatty acids as such are not suitable for very cold
conditions. The esters of these acids also easily crystallize out
of, for instance, olive oil.
[0006] U.S. Pat. No. 6,129,772 discloses a fuel additive,
manufactured from saturated fatty acids and from oligomeric fatty
acids, in which tertiary amines are used to prevent
crystallization. The patent emphasizes especially that mixtures of
different saturated fatty acids are not used, but gives no reasons
for this.
[0007] U.S. Pat. No. 5,578,090 discloses a fuel and a fuel
additive, which is characterized in that it is composed of the
esters of fatty acids, some of which are glycerine esters and some
are triglycerides.
[0008] WO 94/17160 discloses a fuel additive, comprising a fatty
acid, which is esterified using alcohol containing one or several
carbons.
[0009] EP 826765 discloses a corresponding diesel-fuel additive,
which is a fatty acid and a partial ester of polyol, for example,
glycerine and an ester of monocarboxylic acid, 75-200 ppm of which
is added to middle distillates.
[0010] U.S. Pat. No. 3,765,850 discloses an additive obtained by
permitting dicarboxylic acid to react with polyamides.
[0011] U.S. Pat. No. 6,156,082 discloses that it is preferable if a
fuel lubricant is not esterified, as the lubricity will then
suffer. However, this patent describes partial esterification with
diethylene glycol and an organic acid anhydride, which results in
excellent lubricity.
[0012] U.S. Pat. No. 6,194,361 discloses that a usable lubricant
can be obtained from the distilled fatty acids of tall oil by
allowing the fatty acid of tall oil to react with diethanolamine
and then allowing the fatty acid to react with
aminoethylpiperazidine after the previous reaction. This compound
is used, among other things, for lubricating oil wells, both with
oil and as a water emulsion.
[0013] U.S. Pat. No. 6,197,731 discloses that a suitable lubricant
for two-stroke engine fuel can be obtained by esterifying polyols
with polycarboxylic acids.
[0014] JP 08092581 discloses how the --OH group of castor oil can
be esterfied with a saturated monovalent fatty acid to obtain a
lubricant that will operate at very low temperatures.
[0015] U.S. Pat. No. 6,086,645 discloses how a fuel additive can be
advantageously obtained by manufacturing amides of carboxylic acids
for this purpose from oleic acid and/or linolenic acid.
[0016] U.S. Pat. No. 5,882,364 discloses a corresponding fuel
additive comprising the esters of an unsaturated fatty acid and a
polyvalent alcohol, two grades of which are mixed together in the
same mixture.
[0017] U.S. Pat. No. 6,203,584 discloses a fuel additive comprising
esters of polybasic carboxlic acid and polyoxyamine and a mixture
of carboxylic acid and an ester of polyvalent alcohol, which acts
with them.
[0018] U.S. Pat. No. 5,997,593 discloses a fuel lubricant
comprising the reaction product of carboxylic acid and an amine, in
which the said amine is guanidine, amino guanidine, urea, or
thiourea.
[0019] U.S. Pat. No. 6,051,039 discloses a diesel fuel additive,
which is obtained from an amine of dicarboxylic acid, which is an
amine derivative of succinic acid or phtalic acid and their
mixture, as well as of an NR.sub.3 amine, in which R contains 6-24
carbons. The mixture is added to diesel fuel in a concentration of
at least 1000 ppm.
[0020] U.S. Pat. No. 5,556,972 discloses how fats can be
fractionated by crystallizing a stearin ester fraction from an
oleic acid fraction in two stages and removing the said stearin fat
fraction by filtration. This reduces the cloud point of the fat.
The process is carried out by countercurrent crystallization, which
thus reduces, for example, the congealing point of margarine.
[0021] U.S. Pat. No. 5,952,518 discloses a method, by means of
which fatty acids with a high melting point can be removed from
other fatty acids. In this case, the assistance of an emulsifier is
used, the mixture is cooled, and the saturated fatty acids are
removed from the mixture by crystallization. Esters of a polyvalent
alcohol and a fatty acid are used as the emulsifier. The fatty
acids are hydrolyzed rapeseed or soya oils.
[0022] The fatty acids of tall oil, as stated in many patents, act
well as fuel lubricants in combustion engines, as do their alcohol
esters with alcohols, and the amines of fatty acids. However, the
fatty acids as such would be the best lubricants.
[0023] Saturated fatty acids and their derivatives are stated to
act particularly well as lubricants.
[0024] Particularly stearic acids and their salts have been used
throughout history as good lubricants.
[0025] The present invention is intended to create a lubricant
based on fatty acids and a method for manufacturing it for use as a
fuel additive to improve lubrication. This is achieved in the
manner stated to be characteristic in the accompanying Claims.
[0026] According to this invention, the question is how to very
advantageously eliminate the said problems and drawbacks, when
using compositions of tall oil and other fatty acids as an internal
lubricant in fuel at low temperatures.
[0027] According to the invention, the fatty-acid composition is
given a cold-treatment, preferably using such a heat exchanger, in
which the fatty-acid composition is circulated, until a sufficient
share of the amount of the fatty acids has crystallized on the
heat-transfer surfaces of the heat exchanger being used and
essentially only unsaturated fatty acids flow out of the
composition.
[0028] Typically, saturated fatty acids crystallize out of a tall
oil fatty-acid composition already at a temperature of 10.degree.
C., most of the stearic acid crystallizing already at a temperature
of 5.degree. C. The rest will also crystallize at the temperature
range 5-10.degree. C. Normally, the crystallization process is slow
and can take many days when the said fatty-acid mixtures stand in a
vessel. This is due to the low diffusion coefficient and the high
viscosity in cold conditions. When the composition is pumped
through a heat-transfer surface, the low diffusivity is compensated
by the mass transfer caused by the flow as such.
[0029] Now that the saturated fatty acids have been made to
solidify on a heat-transfer surface, they can be removed from the
surface by separately heating it. Thus a new fatty-acid composition
is obtained, which has a substantially greater amount than before
of saturated fatty acids, typically palmitinic acid, stearic acid,
and arachinic acid. Typically these total, for example, 2-4% by
weight of a tall oil fatty-acid composition. The melting point of
unsaturated fatty acids is much lower than that of saturated fatty
acids, but the lubricating properties of saturated fatty acids are,
in turn, better, which is a generally known fact.
[0030] The separated saturated fatty acids can be preferably
esterified, aminated, and permitted to react with enhancing cyclic
compounds, such as lactams, oxazolidines, and similar. It is
generally known that the melting point, solidifying point, or the
pour point known in technology of each mixture occurs at a lower
temperature, the more the mixture contains related but not
identical compounds. Further, it is possible to envisage and claim
that the more a mixture contains such compounds (in this case
fatty-acid compounds), which form steric inhibitions to
crystallization, branchings, branches, pendant groups, etc., then
the lower will be the temperature at which the mixture will
solidify, or at which crystals or a separate phase of some compound
will precipitate from it.
[0031] According to the present invention, at least most of the
saturated fatty acids are separated from a fatty-acid composition
by crystallization at a low temperature, and are made to react with
an alcohol mixture, preferably with waste, i.e. fusel oil, obtained
from the manufacture of alcohol, which contains many alcohols with
a high boiling point, so that a mixture of many esters will be
obtained directly. Some of the saturated fatty acids are, in turn,
made to react with amines, particularly with N,N-dimethyl or
N,N-diethyl amines, when an excellent solvent and a low melting
point for the said solvent will be obtained.
[0032] Part of the saturated fatty-acids separated from the
composition can be advantageously made to react at an increased
temperature and in the presence of an acid catalyst with lactams,
preferably with capric lactam. This reaction must not include a
large number of unsaturated fatty acids, because polymerization
takes place easily and a solid phase with a high melting point will
be obtained (+50.degree. C.).
[0033] Before the reaction with amines, preferably N,N-dimethyl or
diethyl amines, a small amount of an oleic acid-linoleic acid
mixture can be added to the mixture, thus providing an advantageous
solvent for other reactions.
[0034] Thus, according to the present invention, saturated fatty
acids are separated from a fatty-acid mixture by crystallizing
them, preferably on cold heat-transfer surfaces, the mixture of
essentially saturated fatty acid being separated by heating the
said heat-transfer surface and given an esterifying treatment in
the presence of an acid catalyst, preferably using an alcohol
mixture containing many different alcohols and/or a part of the
said mixture of saturated fatty acids being allowed to react with
amines, preferably with N,N-diamine and/or a part being permitted
to react with lactams, preferably with capric lactam, at an
increased temperature, and at least one of these reaction mixtures
being remixed with the original mixture made from essentially
unsaturated fatty acids.
[0035] The aforementioned method has advantages, including the fact
that only part of the fatty acids, generally 2-5%, must be treated
and the best fatty acids, even though modified, can be used for
lubrication. If the separate and modified fraction is
multi-modified, the solidification point of this fraction will be
at a lower temperature than if it had been esterified or aminated
using only a single reagent.
[0036] The reaction product of capric lactam and fatty acids is
like vaseline, provided the reaction of the product is stopped at a
suitably early stage, for example, 30 min/150.degree. C. If the
product is kept hot, for example, for 2 hours, a relatively solid
product will result, which will not longer optimally suit the
purpose referred to here. The catalyst used is an acid catalyst,
para-toluenesulphonic acid, Lewis acid, or concentrated cation
exchange resin or sulphuric acid, which must, however, be washed
out. Normal Lewis acids, such as AlCl.sub.3 are very suitable for
this purpose.
[0037] When aminating fatty acids, there is reason to use
advantageously N,N-dimethyl or ethyl fatty-acid amines, as they do
not form hydrogen bridges with each other and thus remain liquid at
room temperature.
[0038] When esterifying fatty acids, one of the cheapest raw
materials is an alcohol mixture, which in the alcohol industry goes
by the name of fusel oil. If this is used in esterifying, many
esters of fatty acids and acids will be obtained at one time, while
a low solidification point for the reaction mixture will also be
obtained.
[0039] The product thus obtained is typically mixed with diesel
fuel to form a 0.01-0.04% mixture.
EXAMPLE 1
[0040] A tall oil-fatty acid mixture, which according to analysis
contained palmitinic acid 0.4%, stearic acid 1.1%, and arachid acid
0.4%, was cooled to and kept cooled at a temperature of
+5.5.degree. C., until no further sediment was deposited from it.
In this case, the solution was filtered, the filtration producing
about 50 ml of mixture from a litre of the original composition.
The solidification point of the sediment was 35.degree. C. The
composition of this mixture contained 8.3% of stearic acid (1.1% in
the original mixture). It is obvious that filtration in a
laboratory will not produce such good results as crystallization on
cold heat-transfer surfaces, because a large amount of the other
acids present in the mixture will remain between the crystals of
the sedimented stearic acid.
EXAMPLE 2
[0041] 29 g of the stearic-acid concentrate obtained in Example 1
and 10 g of capric lactam were allowed to react with each other
with a small amount of AlCl.sub.3 acting as a catalyst while being
mixed for 2.5 hours, during which time the melting point of
40.degree. C. had dropped to a value of 35.degree. C. The result
was a viscous golden-brown liquid, which was like vaseline at room
temperature. Later, a part of it precipitated, which solidified
when the mixture was kept for 2 days at a temperature of 60.degree.
C., in other words, it had continued to polymerize.
EXAMPLE 3
[0042] Fusel oil traditionally contains salts that can be removed
prior to use in esterification, for example, by distillation.
However, in this case the salts were removed in another way; i.e.
the fusel oil was cooled to a temperature of -18.degree. C., when
about one-fifth of the water precipitated as a salt phase, which
was removed together with the salts, the remainder being used as
follows.
[0043] Thus, stearic acid was esterified using an alcohol mixture,
of so-called fusel oil, which was obtained from the waste of the
distillation of ethanol. The composition of the fusel oil was:
propanol 3 w-%, isobutanol 24 w-%, 2-methyl-1-butanol 12 w-%,
3-methyl-1-butanol 37 w-%, ethanol 8 w-%, water 14 w-% ja solids in
the form of salts 0.5 g/litre, which were removed according to the
above procedure.
[0044] 10 g stearic acid (sp 67-69.degree. C.) was mixed with 80 ml
of the fusel oil described above and a small amount (2 drops) of
sulphuric acid was added. The mixture was first heated, while being
mixed, at a temperature of 94.2.degree. C. for 2 hours, after which
the surplus alcohols were distilled out, when the remainder of the
alcohols also began to leave at a temperature of 145.degree. C. The
mixture was washed with water to remove the acid residues. The
remaining ester mixture was still entirely fluid and clear at a
temperature of +14.5.degree. C. It will be obvious to one versed in
the art that if the said esterification has been carried out using
the stearic-acid concentrate referred to previously, a clearly
smaller amount of processing could have been achieved, as the
relative amount of saturated fatty acids would have been
greater.
EXAMPLE 4
[0045] 30 g of the fatty-acid mixture of Example 1, concentrated in
relation to stearic acid, was allowed to react with 13.6 g of
di-N-butyl amine, using a drop of sulphuric acid as a catalyst, at
a temperature of 120.degree. C. for 4 hours while mixing, a pale
orange liquid being obtained, which was highly fluid at a
temperature of +7.degree. C. A clear increase in the viscosity of
the liquid began only at a temperature of +2.degree. C. while it
began to form a solid phase only at a temperature of -1.degree.
C.
EXAMPLE 5
[0046] The solution remaining in Example 2, which was a light brown
liquid, with a viscosity clearly greater than that of fatty acids,
was mixed with the filtrate of Example 1, in which there was thus a
large amount of unsaturated fatty acids, together with the amine
esters of stearic acid manufactured in Example 4, in which case the
amount corresponded to the amount of the `stearic-acid fraction`
removed by crystallization. The fatty-acid mixture thus created was
allowed to stand for several days at a temperature of +2.degree.
C., during which time no sediment appeared in it, even though the
same original product (Example 1, +5.degree. C.) continued to
crystallize significantly in the same conditions.
EXAMPLE 6
[0047] The same amount that had been removed of both the
alcohol-esterfied stearic acid and the mixture of saturated fatty
acids esterified using di-N-butyl amine (the sediment that had been
filtered from the original solution at a temperature of +2.degree.
C.), were added to the fatty-acid mixture of Example 1, from which
the saturated fatty acids that had crystallized at a low
temperature had been filtered out.
[0048] This solution was kept at a temperature of -1.degree. C. for
7 days. No sediment was deposited from it, nor did it become
cloudy. At the same time, further sediment began to settle, at the
same temperature, from the alkali solution from which sediment had
been removed at a temperature of +2.degree. C.
EXAMPLE 7
[0049] 28 g of the sediment of saturated fatty acids separated
according to Example 1 was melted and 10 g of capric lactam and 2
drops of AlCl.sub.3 solution were added to it and the reaction was
allowed to proceed while mixing at a temperature of 150.degree. C.
for 60 minutes. The result was a vaseline-like product with a
solidification point of 35.degree. C., the solidification point of
the original liquid being 40.degree. C. An amount of this product
corresponding to the stearic acid and arachid acid together with
the fusel-oil esters was mixed with the filtrate according to
Example 1, so that there was as much of each reaction product
calculated as stearic acid, as had been removed from it. After
being allowed to stand for 3 days at a temperature of -1.degree.
C., an amount of needle-like crystals, which were only just visible
to the naked eye, was deposited from the product. When the crystals
were melted and the product was allowed to stand for 4 days, at a
temperature of +5.degree. C., no further sediment or crystals were
formed.
[0050] When a mixture of esters of di-N-butyl amine stearic acid,
arachid acid, and palmitinic acid of 0.5 ml per 100 ml was added to
this mixture, a fatty-acid solution was created, from which nothing
further was deposited at -1.degree. C. The product was also noted
to have an easily emulsifying effect on water.
* * * * *