EP0152663A1

EP0152663A1 - Fuel detergent additives comprising benzophenone derivatives and fuel compositions containing them

Info

Publication number: EP0152663A1
Application number: EP84301095A
Authority: EP
Inventors: Harry John Andress
Original assignee: Mobil Oil Corp
Current assignee: ExxonMobil Oil Corp
Priority date: 1984-02-21
Filing date: 1984-02-21
Publication date: 1985-08-28
Also published as: EP0152663B1; DK87384A; DK163881B; DE3474835D1; DK163881C; ATE38244T1; AU579170B2; DK87384D0; AU4560285A

Abstract

Benzophenone tetracarboxylic dianhydride, and esters or mixtures thereof when reacted with various hydrocarbyl amines provide automotive fuel additives for liquid hydrocarbon fuels, and such additives are highly useful as fuel detergents, intake valve and exhaust gas valve deposit reducers and as agents for preventing undesired deposits in the carburetor of an internal combustion engine in which liquid hydrocarbon fuels are normally susceptible to forming such deposits.

Description

This invention relates to fuel detergent additives comprising benzophenone derivatives and to liquid hydrocarbon fuels containing them, such liquid hydrocarbon fuels normally being susceptible to forming undesirable carburetor and intake valve deposits in automotive and other internal combustion engines.
It is well known to those skilled in the art that liquid hydrocarbon fuels such as gasolines and fuel oils tend, on combustion, to form undesirable deposits on carburetor and intake valves in internal combustion engines. It is also well known that a great deal of effort has been directed to provide means to overcome such problems. The formatim of such deposits tends to impair engine efficiency and often results in breakdown, necessitating cleaning operations and frequently costly replacement of engine parts. This situation is particularly critical in the use of modern liquid hydrocarbon fuels such as gasolines, jet fuels, diesel fuels and other fuels employed in the operation of advanced internal combustion engines.
Various chemical additives have been used with varying success to overcame the adverse effects described above. Nevertheless, a strong need still exists for fuel additives capable of reducing carburetor and intake valve deposits. This invention is a response to that need. However, to applicant's knowledge, the benzophenone derivatives as disclosed herein have not been used or suggested by the prior art for such purpose and are novel.
In accordance with the present invention, it has been found that the undesirable formation of carburetor and intake valve deposits in internal combustion engines can be significantly reduced by adding minor amounts of benzophenone tetracarboxylic dianhydride (BTD) amine derivatives or esters thereof or mixtures of the dianhydride and esters to the liquid hydrocarbon fuels used in said internal combustion engines. The benzcphencne tetracarboxylic dianhydride and its esters are reacted with various suitable amines to give said additives that are fuel detergents and which provide in garticular intake valve and exhaust gas recirculation valve deposit reduction.
According to the present invention, there is provided a fuel detergent additive which comprises a reaction product of

(a) a benzophenone tetracarboxylic dianhydride, an ester of such a dianhydride, or a mixture of such a dianhydride and such an ester, and
(b) an hydrocarbyl amine, the additive having been produced by the reaction of the benzqphenone tetracarboxylic dianydride, ester thereof, or mixture of dianhydride and ester, with the hydrocarbyl amine in a mole ratio of about 3:1 to about 1:3 at a temperature of about 100 to about 300°C at atmospheric pressure for a time sufficient to substantially complete the reaction.

The invention also provides an automotive fuel composition which comprises

(i) a major amount of a liquid hydrocarbon fuel having an initial boiling point of at least about 24°C (75°F) and an end boiling point of about 399°C (750°F), and
(ii) a minor amount of an additive as described above.

The liquid hydrocarbon fuels improved in accordance with the invention comprise fuels which are normally susceptible to forming undesirable carburetor and intake valve deposits. Specifically, such liquid hydrocarbon fuels boiling from about 24°C (75°F) to about 399°C (750°F), include gasoline, jet fuel and diesel fuel. Of particular significance is the treatment of petroleum distillate fuels having an initial boiling point of about 24°C (75°F) to about 57°C (135°F), and an end boiling point of from about 121°C (250°F) to about 399°C (750°F). It should be noted in this respect that the term "distillate fuels" or "distillate fuel oils" is not intended to be restricted to straight run distillate fractions. These distillate fuel oils can comprise straight run distillate fuels, catalytically or thermally cracked including hydrocracked distillate fuel oils or mixtures of straight run distillate fuel oils, naphthas and the like with cracked distillate stocks. Morever, such fuel oils can be treated in accordance with well known commercial methods such as acid or caustic treatement, hydrogenation, solvent refining plate treatment and the like.
Distillate fuels are characterized by their relatively low viscosity and pour point. The principal property which characterizes these hydrocarbons however, is their distillation range, which as hereinabove indicated, will lie between about 24°C (75°F) and about 399°C (750°F). Obviously, the distillation range of each individual fuel will cover a narrower boiling range and each fuel will boil substantially continuously throughout its distillation range. Particularly contemplated among the fuels are gasolines, leaded or unleaded; fuel oils such as Nos. 1, 2 and 3, used in heating; and jet combustion fuels. The domestic fuel oils generally conform to the specifications set forth in ASTM Specification D396-4AT. Specifications for diesel fuels are defined in ASTM Specification D975-4AT. Typical jet fuels are defined in Military Specification MIL-F-5 624B. In addition, as hereinbefore indicated, fuel oils of varying viscosity and pour points falling both within and outside the indicated range may also be effectively treated through the use of additives of the present invention.
Additives in accordance with the invention are employed in liquid hydrocarbon fuels in minor amount, i.e. from about 0.001 to about 10 weight percent, and prefereably from about 0.01 to about 0.5 weight percent based on the total weight of the fuel. Any other known additive (antioxidant, dispersant, antiwear agent, etc.) generally may also be used for its known purpose up to about 5 to 10 weight percent based on the total weight of the fuel composition without adverse effect.
In general, the benzophenone tetracarboxylic dianhydride and its derivatives may be prepared by reacting same with an appropriate amine. For example, a mixture of benzophenone tetracarboxylic dianhydride and an alkanol can be reacted to form the ester which is then reacted witn a suitable hydrocarbyl amine. The esterification reaction is usually carried out under suitable nitrogen pressure at a temperature of from about 150°C to about 250°C, and preferably from about 180°C to about 210°C until tne reaction is substantially complete, i.e., depending on specific reaction parameters up to five hours or more. The alkyl group of the alkanol may contain from 1 to about 36-72 carbon atoms. The benzophenone dianhydride and alkanol are reacted in a mole ratio which may vary from about 1:4 to about 4:1, and preferably from about 1:4.
The product ester of the benzophenone tetracarboxylic acid may then be reacted with an amine at atmospheric pressure wherein the reaction temperature can vary from about 100°C to about 300°C, and the mole ratio of ester to amine is from about 3:1 to about 1:3 for periods of from about three to ten hours.
Any suitable hydrocarbyl amine may be used; for example, polyethylene amines, polypropylene amines, primary and secondary straight chain and branched chain amines, alkenyl succinimides.
The following specific examples and comparative data set forth below indicate clearly that the fuel additives and compositions of the present invention are highly effective for their intended purpose.

EXAMPLE 1

A mixture of 400 grams (1.35 moles) benzophenone tetracarboxylic dianhydride, 854 grams (5.4 moles) isodecanol, and 1 gram E-toluene sulfonic acid were stirred to about 200°C over a five hour period using a slow stream of nitrogen gas to aid in the removal of water. The product was the tetraisodecyl ester of benzophenone tetracarboxylic acid.

EXAMPLE 2

A mixture of 980 grams (1.1 moles) of the product from Example 1 and 50 grams (0.38 moles) of tetraethylene pentamine were stirred to about 260°C over a seven hour period to form the desired reaction product.

EXAMPLE 3

A mixture of 892 grams (1 mole) of product from Example 1 acid and 91 grams (0.48 mole) of tetraethylene pentamine were stirred to about 250°C over an eight hour period to form the desired reaction product.

EXAMPLE 4

A mixture of 313 grams (1.05 moles) benzophenone tetracarboxylic dianhydride and 850 grams (4.24 moles) of a commercially available mixture of branched C₁₂ primary amines were stirred to about 220°C over a six hour period to form the corresponding tetra amide of benzophenone tetracarboxylic acid.

EXAMPLE 5

A mixture of 173 grams (0.58 mole) benzophenone tetracarboxylic dianhydride and 615 grams (2.32 moles) of a commercially available mixture of primary C_16-18 amines derived from tallow were stirred to about 270°C over an eight hour period to form the tetra amide of benzophenone tetracarboxylic acid.

EXAMPLE 6

A mixture of 315 grams (1.06 moles) benzophenone tetracarboxylic dianhydride acid, 1384 grams (4.24 moles) of an amincpropyl substituted oleylamine were stirred to about 255°C over an eight hour period to form the desired reaction product.

EXAMPLE 7

A mixture of 1018 grams (0.52 mole) of a bis-succinimide (formed by reacting one mole of tetraethylene pentamine with two moles of C₁₈ to C₂₄ dimer alkenyl succinic anhydride) and 76 grams (0.26 mole) benzophenone tetracarboxylic dianhydride were stirred to about 260°C over a four hour period to give the desired reaction product.

EXAMPLE 8

The base fuel and the base fuel plus the additives as specified below were thereafter subjected to the following test to determine the effectiveness of fuels incorporating the additives in accordance with the invention in preventing carburetor throttle body deposits.

Carburetor Detergency Test

I. PROCEDURE

A six-cylinder, 3933 cc (240 cubic inch) truck engine with exhaust gas recirulcation is operated for twenty hours on a cycle consisting of a seven-minute idle followed by a thirty-second part-throttle acceleration to 2000 rpm. A controlled amount of the engine's blowby gas is metered into the intake air to induce deposit formation. The ability of a fuel to prevent deposit formation is determined by weighing the removable aluminum throttle sleeve before and after the test and also by visual rating of the sleeve.

II. EQUIPMENT DESCRIFTION

A. Standard Engine

It is readily apparent from the data of the Table that the additives of the inventicn are highly effective in reducing the formation of carbonaceous deposits from liquid hydrocarbon fuels onto surfaces of various parts of internal combustion engines.

Claims

1. A fuel detergent additive which comprises a reaction product of

(a) a benzophenone tetracarboxylic dianhydride, an ester of such a dianhydride, or a mixture of such a dianhydride and such an ester, and

(b) an hydrocarbyl amine, the additive having been produced by the reaction of the benzophenone tetracarboxylic dianhydride, ester thereof, or mixtures of dianhydride and ester, with the hydrocarbyl amine in a mole ration of about 3:1 to 1:3 at a temperature of about 100 to about 300°C at atmospheric pressure for a time sufficient to substantially complete the reaction.

2. A fuel detergent additive according to claim 1, wherein the benzophenone tetracarboxylic dianhydride reactant (a) comprises a mixture of benzophenone tetracarboxylic dianhydride and an alkanol having from one to seventy-two carbon atoms per molecule.

3. A fuel detergent additive according to claim 1 or claim 2, wherein the benzophenone tetracarboxylic dianhydride reactant (a) comprises a mixture with an alkanol to produce an ester thereof with a mole ratio of anhydride to alkanol of about 1:4 to about 4:1.

4. A fuel detergent additive according to any one of claims 1 to 3, wherein the alkanol is isodecanol.

5. A fuel detergent additive according to any one of claims 1 to 4, wherein the hydrocarbyl amine reactant (b) comprises tetraethylenepentamine.

6. A fuel detergent additive according to any one of claims 1 to 4, which comprises the reaction product of

(a) benzophenone tetracarboxylic dianhydride or an ester thereof or a mixture of such a dianhydride and such an ester, and

(b) a mixture of branched tetra-C₁₂ primary amines.

7. A fuel detergent additive according to any one of claims 1 to 4, which comprises the reaction product of

(a) benzophenone tetracarboxylic dianhydride, and

(b) a mixture of primary C_16-18 amines derived from tallow.

8. A fuel detergent additive according to any one of claims 1 to 4, which comprises the reaction product of

(a) benzcphenone tetracarboxylic dianhydride, and

(b) an amincprc^pyl-substituted oleylamine.

9. A fuel detergent additive according to any one of claims 1 to 4, which comprises the reaction product of

(a) benzophenone tetracarboxylic dianhydride, and

(b) a succinimide.

10. A fuel composition comprising

(i) a major amount of a liquid hydrocarbon fuel having an initial boiling point of at least about 24°C and an end boiling point of about 399°C, and

(ii) a minor amount of a fuel detergent additive according to any one of claims 1 to 9.