US3042505A - Multi-functional middle distillate additive - Google Patents

Description

United States Patent ()fifice 3,042,505 Fatented July 3, 1062 3,042,505 MULTI-FUNCTIONAL MIDDLE DISTILLATE ADDITKVE William C. Hollyday, Jr., Plainfield, N.J., assignor to Esso Research and Engineering Company, a corpora- -tion of Delaware No Drawing. Filed Oct. 18, 1960, Ser. No. 63,259 5 Claims. (Cl. 44--62) The present invention is concerned with an improved multi-functional additive suitable for addition to middle distillates which will give these middle distillates improved pours, higher stabilities, higher detergences and also improve the sludge characteristics. More particularly, the present invention relates to the preparation of improved low cold test hydrocarbon fuels, especially in heating oils and diesel fuels, kerosene, aviation turbojet fuels, and other fuels that are subject to low temperatures. In accordance with the present invention, an improved class of pour depressants is utilized with middle distillates which comprise condensation products of an acylated polystyrene with various arnino compounds.

With the increase in the use of hydrocarbon fuels of all kinds, a serious problem has arisen in areas frequently subject to low temperatures in the cold test characteristics of fuels. Particularly, serious problems have been encountered by heating oils and diesel and jet fuels that have too high a pour point, resulting either in distributional or operating difiiculties or both. For example, the distribution of heating oilsby pumping or syphoning is rendered difficult or impossible at temperatures around or below the pour point of the oil. Furthermore, the flow of the oil at such temperatures through the filters cannot be maintained, leading to the failure of the equipment to operate.

It is well known to add pour depressants to lubricating oils to lower the pour point. These lube oil additives, mostly high molecular weight organic compositions formed by alkylation of benzene or naphthalene or derivatives thereof or by polymerization of lower molecular weight methacrylates, or by condensation polymerization of various kinds, are not satisfactory in service with middle distillate and lighter fuels. Poor performance of these additives might possibly result from the structural differences between waxes occurring in lubricating oils and so-called middle distillates.

A wide variety of compounds have been found to be effective as pour point depressants for lubricating oil. Among the best known are Paraflow, Santopour and Acryloid and their modifications. They are prepared either by condensing aromatic compounds with long chain paraflins, such as wax, or by condensing olefinic esters. It is generally considered that these pour depressants are effective in that in cooling an additive-containing oil, the hydrocarbon chain of the additive becomes incorporated into the crystal lattice of the separated wax, while the other part of the pour depressant molecule prevents the crystals from adhering together to form a gel strutcure. The failure of these additives to be effective in middle distillates may at least in part be due to the basic diiference in the composition between the wax in lubricating oils and that in middle distillate fuels.

It is, therefore, one object of the present invention to set forth an improved pour depressant for middle distillate and lighter fuels. The boiling ranges of these oils are generally about 250 to 750 F. Another object of the present invention is to use a multi-functional middle distillate additive for the improving of stabilization, the detergency, and the sludge characteristics of these fuels.

The petroleum distillate fuels in which the additive materials of the invention are employed consist of a major proportion, at least 95% of liquid hydrocarbons boiling at temperatures between about F. and about 750 F. These fuels include gasolines such as aviation, marine and automotive or motor gasolines, aviation turbojet fuels such as lP-l, JP-4 and JP'5 fuels, and diesel fuels such as marine, stationary and automotive diesel engine fuels.

Aviation turbo-jet fuel consists of at least of a mixture of volatile hydrocarbons. It is defined by US. Military Specifications MIL-F-5616 and MIL-F-5624C. its volatility is such that its end point does not exceed 572 F. Its viscosity is between 0.5 and 1.5 centistokes at F.

Diesel fuels as referred to in connection with the invention consist of at least 95 of a mixture of hydrocarbons boiling between 250 F. and 750 F. either by ASTM Method D 8656 when their end points do not exceed 600 F. or by ASTM Method D-l58-54. Diesel fuels are defined by ASTM Specification D975-53T and fall into Grades 1D, 2D and 4D, in all of which the additive materials of the invention may be used. They have viscosities between 1.4 and 26.4 centistokes.

The liquid fuels in which the additive materials may be incorporated thus comprise at least 95 by weight of a mixture of hydrocarbons having a boiling range between the limits of 75 F. and 750 F. and a viscosity between the limits of 0.264 and 26.4 centistokes at 100 F.

As pointed out heretofore, the new polymeric materials of the present invention giving improved pour, stabilization, detergency, and sludge dispersion characteristics to a middle distillate fuel, are prepared by the condensation of acylated polystyrene with amino compounds.

The acylated polystyrene compounds are prepared with certain fatty acid chlorides of critical composition and are active pour depressants for middle distillates. The acylates of interest have the following structure:

is defined according to the contributory number table and R is normally a straight chain alkyl group of about C to C and X is a number from 3 to 20.

In general, the method of acylation may vary appreciably. The methods which are disclosed in US. Patent No. 2,703,817, entitled Process for the Preparation of Lubricating Oil Additives," Inventor: George E. Serniuk, and in US. Patent No. 2,500,082, entitled Acylated Derivatives of High Molecular Weight Copolymers, Inventors: Eugene Lieber and William H. Smyers, may be utilized.

Broadly, the method of acylation comprises dissolving the polystyrene in a suitable solvent, such as chlorobenzene, o-dichlorobenzene, or tetra chloro-ethylene and adding to the solution the equimolar carboxylic acid chlo ride/ aluminum chloride complex at temperatures of 30 to 70 C. (preferably, 40 to 60 C.), with provision for 70 carrying away the evolved hydrogen chloride.

After all the acid chloride/ aluminum chloride complex has been added (one mole per mole of phenyl groups in aluminum chloride.

the polystyrene, plus a slight excess) and hydrogen chlo ride evolution has stopped, the catalyst is destroyed with Water or alcohol, the acylate is taken up in a suitable solvent, such as heptane or kerosene and washed with Water and alkaline solutions. The resinous product may be isolated as the pure material by evaporating all solvents, or it may be used in solution for making blends in middle distillates.

For obtaining the superior acylated polystyrene, it is desired that the polystyrene starting material have an intrinsic viscosity within a range of about 0.2 to 2.0, preferably 0.8 to 1.5. These viscosities correspond to molecular weights within a range of from about 10,000 to 75,000, preferably 30,000 to 60,000 Staudinger (if the constant for isobutylene polymers is assumed to apply). Since the amounts of the other reactants are based on the weight of the polystyrene, the amount of polystyrene used will depend upon restrictions such as equipment capacity, etc. The cryoscopic molecular weight after acylation was about 700 to 5,000; the intrinsic viscosity about 0.05 to 0.5. The 700 molecular weight comprises, in essence, a trimer containing three acylated phenyl groups, Whereas, the 5,000 molecular weight comprises, in essence, about 18 acylated phenyl groups, on the average, per polymer molecule.

The acylating agent chosen for the preparation of the acylated polystyrene of this invention will be aliphatic in nature and will preferably contain from 8 to 16 carbon atoms in a straight chain. Although C C C C and C acid chlorides are used in the examples specifically detailing the instant invention, any straight chain acid chlorides having the above requirements may be used. It is preferred that equimolar quantities of polystyrene and the acylating agent be used, however, from 0.80 to 1.20 mols "of acylating agent per mol equivalent of polystyrene is operable. A large excess of acylating agent does not harm, but it does not react and so is wasted. As mentioned, suitable acyl groups include acetyl, butyryl, capryl, decanoyl, do-decanoy-l, tetra-decanoyl, hexadecanoyl stearoyl and benzoyl.

These acylates are condensed with primary and secondary aliphatic and aromatic amines such as methyl amine, n-propyl amine, t-butyl amine, n-octyl amine, ndo-decyl amine, n-octadecyl amine, aniline, N-methyl aniline, N-ethyl aniline, p-amino phenol, p-methoxy aniline, p-amino phenyl stearate, alpha-naphthylarnine and beta-naphthylamine.

These. compounds may be prepared in the following manner.

EXAMPLE 1 CH=CHg 2) x X XRCOCl/AlCla O Simultaneous polymerization and acylation of polystyrene were carried out by the addition of a solution of 1.00 mole weight (104 g.) of polystyrene in o-dichlorobenzene solvent to an acid chloride/ aluminum chloride complex. The complex contained 0.35 mole of n-dodecanoyl chloride, 0.35 mole of n-tetra decanoyl chloride, 0.35 mole of n-decanoyl chloride and 1.05 moles of anhydrous The temperature was maintained at 5 to 40 C. during the reaction. The product was recovered by Washing the reaction mixture with alkaline solutions and evaporating the solvent. The polymeric 'product had an intrinsic viscosity of 0.05 and was ob- "tained in a yield of 96% of the theoretical, based on the assumption that the product contained one acyl group per phenyl group.

The acylated polystyrene prepared as described was The temperature was C. and the catalyst a few pellets of sodium hydroxide. The following reaction took place:

+ m n H20 o=o-R C 2Hz5N=CR Benzene and water were removed by distillation. The polymeric product contained 1.99% nitrogen, which indicates that about two-thirds of the acyl groups reacted with amine.

EXAMPLE 2 Various amounts of the pour depressants of the present invention were utilized in distillate fuels. A typical distillate fuel boiling in the range from 250 to 750 F. to which the present additives may be added are middle distillate heating oils. These fuels are of commercial grade and have typical properties as follows.

The improvements obtained by adding the additives in accordance with the present invention are set forth in the following table. All pour points quoted hereafter were obtained by ASTM Method D-97-47.

The heating oil from Venezuela crude had a boiling range of 354-624 R, an API gravity of 37.6 and a viscosity of 2.35 cs. at 100 F. The heating oil from Canada crude had a boiling range of 316 to 685 R, an API gravity of 35.4, and a viscosity of 2.85 cs. at 100 F.

Table I POUR DEPRESSANT ACTIVITY OF ACYLA'IED POLYSTY- RENE/AMINE OONDENSATE Test Oil Description Wt. percent Po Polymer 1 Point, F

0. 01 5 Heating Oil from Venezuela Crude 8' Ii, 0. 05 15 0. 10 -15 0. 00 +10 0. 01 0 Heating Oil from Canada Crude 8' g; :%g 0. 05 35 0. 10 -40 1 Acylated polystyrene/amine condensate from Example 1.

EXAMPLE 3 In other tests, the effectiveness of the additives in controlling sediment were carried out. The results of these runs are shown in the following Table II. The heating oil used had a boiling range of 382660 R, an API gravity of 35.0 and a viscosity of 3.10 cs. at 100 F.

Table II POTENTIAL SEDIMENT TEST Test description: A sample of the middle distillate (200 ml.) is carefully filtered and then held at 210 F. for 16 hours, with exposure to air. During this treatment some sediment develops. This potential sediment is reported in mg. per 100 ml. of sample.

Test results:

Pour Potential Heating Oil Tested Point, Sediment,

F. rug/ml.

(A) Mixed Heating Oil (50/50 cracked and 0.45

straight run stocks from Venezuela crude.) (B) Same Heating Oil +0.02 Wt. percent product from Example 1 20 0.10

EXAMPLE 4 In further tests, the efiectiveness in the control of filter plugging were carried out with the following results shown in table III.

Table III ACCELERATED FILTER PLUGGING TEST Test results:

Dernerits Liters 01' Heating Oil Sample Tested Filtered Pres. Sediment Sediment Overall Drop Appear- Weight (Aver) ance (A) Table II 8. 2 8. 5. 0 3. 8 2 8. 3 (B) Table II 12.0 4. 4 4. 0 3. 7 3 4. 0

1 Ranging from 0 to 10.

1 Average demerit multiplied by the factor 12.0/8.2 because only 8.2 liters filtered.

3 Equal to demerit obtained with commercial stabilizer.

The amount "of the condensation product. used may vary appreciably depending upon the particular stock in which it is used. However, the general range is from about 0.001 to 0.5 weight percent, preferably from 0.05 to 0.1%.

What is claimed is:

1. A petroleum distillate fuel composition having an improved pour and improved stability against sedimentation which comprises essentially a petroleum distillate fuel boiling in the range between 250 F. and about 750 P. which has been improved with respect to pour point by the incorporation therein of a pour depressing eifcctive amount in the range from about .001 to 0.5 wt. percent of a pour depressant which comprises essentially a condensation product of an acylated polystyrene and an amino compound, which condensation product has the following structure wherein R is a straight chain alkyl group of about 7 to 15 carbon atoms, wherein x is a number from 3 to 20, and wherein R is an amino group.

2. Composition as defined by claim 1 wherein said amino compound is a primary aliphatic amine.

3. Composition as defined by claim 1 wherein said amino compound comprises an aromatic amine.

4. Composition as defined by claim 1 wherein said amino compound comprises dodecylamine.

5. Composition as defined by claim 4 wherein the condensation product comprises about 1 mol of dodecylamine per mol of acyl groups.

References Cited in the file of this patent UNITED STATES PATENTS 2,703,8 17 Serniuk Mar. 8, 1955

Claims (1)

1. A PETROLEUM DISTILLATE FUEL COMPOSITION HAVING AN IMPROVED POUR AND IMPROVED STABILITY AGAINST SEDIMENTATION WHICH COMPRISES ESSENTIALLY A PETROLEUM DISTILLATE FUEL BOILING IN THE RANGE BETWEEN 250*F. AND ABOUT 750* F. WHICH HAS BEEN IMPROVED WITH RESPECT TO POUR POINT BY THE INCORPORATION THEREIN OF A POUR DEPRESSING EFFECTIVE AMOUNT IN THE RANGE FROM ABOUT .001 TO 0.5 WT. PERCENT OF A POUR DEPRESSANT WHICH COMPRISES ESSENTIALLY A CONDENSATION PRODUCT OF AN ACYLATED POLYSTYREENE AND AN AMINO COMPOUND, WHICH CONDENSATION PRODUCT HAS THE FOLLOWING STRUCTURE