US2518529A - Process for producing synthetic lubricants - Google Patents

Description

Patented Aug. 15, 1950 UNITED STAT PROCESS FOR PRODUCING SYNTHETIC LUBRICANTS Roger Boux de Casson and Lucien Hemmer, Paris, France, assignors to Societe anonyme dite; Standard Francaise des Petroles, a corporation of France No Drawing. Application January 18, 1949, Serial No. 71,562. In France September 12, 1947 1 Claim. (01. 2 471 The. present invention relates to alkylated and polymerized hydrocarbons, and particularly to synthetic lubricating oils produced by alkylating and polymerizing low molecular weight hydrocarbons to increase their molecular weight. The

invention relates also to an improved process of making such synthetic'oils.

It is known that products of'high molecular 'weight and having a high viscosity suitable for use in the lubrication of various mechanisms including steam engines, or internal combustion engines, can be obtained by the polymerization of various olefinic hydrocarbons in the presence of catalysts of the Friedel-Crafts type, such as aluminum chloride, iron chloride, zinc chloride, and boron fluoride.

in the application for French Patent 522,546, filed on the 24th of September, 1946, in the name of the applicants, 'it has beenfsugg'es'ted that olefins such as those obtained by cracking commercial paraflins in the vapor phase and, more particularly, thecracking of 'parafiins of melting points greater than 50 C. be polymerized and also that there be added during the polymerization a certain proportion of a light aromatic hydrocarbon, such as benzene or its homologues. ,This method of operation produces synthetic oils of good quality, possessing remarkable char-- acteristics, with particular respect to the slope ofthe. viscosity temperature curve, the pour point and the Conradson carbon and. the iodine number. The stability and the lubricating properties of these oils, even at high temperatures, justify theiruse in all types of internal combustion engines including aviation engines. 7 j The synthesis process described above, is called alkylation polymerization without these terms being in any way limiting. As by-products of this process, in addition to lubricating oils, lighter synthesis products, comparable to gasoline, gas oil and spindle oil, are also obtained. These products are formed from the aromatic components and the cracking distillate in such large proportions that they cannot be utilized for the manufacture of lubricating oil. The applicants have found further that it is very difficult to obtain oils having an iodine number lower than 10 (of the order of about successfully by the simple process of alykylation polymerization, without too great a sacrifice in the viscosity index of the oils obtained in conversion into viscous oil. The applicants have now discovered, and it is the object of the present invention (1) That all or part of these light products can be advantageously reused in a subsequent V 2 "alkylationpolymerization and that if one uses them integrally, there is no apparent accumulation of any fraction.

(2) That by the process of total recycle, theproduction can be adjusted so as to produce as a total product an oil of the desired viscosity, for exampla'of' the viscosity of a light motor oil, 1.,of 'aheavymotor oil or of a bright stojck. (3)"Th'at'the iodine'number of the oils obtained; by the process is always distinctly lower than that obtained without recycling. r- The reaction of the "alkylationpolymerization? according to the present invention is carried out in the" following manner:

flnto a suitable mixture of benzene and recycled products (obtained from a previous operation), there is introduced with agitation the necessary quantity of anhydrous aluminum chloride. Then, little by little, the paraffin cracking distillate (boiling up to 285 C. at atmospheric pressure) is added. The reaction liberates heat and it is necessary to cool the mixture extensively to keep the temperature below50 C. The lowered temperature is maintained for a substantial period of time, 2 to 8 hours, preferably about 5, hours and then is increased to about to C., preferably l00-1l0 C. for 1 to 4 hours, preferably about 2 hours to complete the reaction.

The product is then decanted. The aluminum chloride sludge formed is separated and the upper layer is neutralized if desired and is treated with a decolorizing clay in the. presence of steam. Finallygit is distilled under vacuum to concentrate theoil and obtain a product of the desired viscosity andflash point characteristics. Thereafter, the light products, not utilizable directly for the manufacture of lubricating oils, are reused in a new operation.

t It is noted that in the above description the range of distillation of the recycled fraction has not been defined as it is possible in applying the previously indicated method to recycle, for example, only the fraction boiling below C.at atmospheric pressure, or the fraction boiling below 300? C. at atmospheric pressure, or even the fractions boiling up to 400 C. at atmospheric pressure (such fractions contain light oils of the transformer oil type). Also only part of these fractions can be used, for example, the fraction boiling between 125 C. and 300 C at atmospheric pressure or the fraction boiling between 12.5? C. and 400 C. at atmospheric pressure. The method of recycling employed does not modify the characteristics of the finished oil in any way. The process according to the present invention Example 1 For comparispn, a first operation .was carried -'out without recycling.

The starting materials --iwere:

Kil g am Benzene V 50.0 Cracking distillate 2000 Aluminum chloride '80 After reaction under the conditions indicated above (below 50 C. for hours then at 100 to 110 C. for 2 hours) and clay treatment and distillation of the products obtained, the following yields were obtained:

Kilograms Sludge (without aluminum chloride) 2% Products to be recycled 1010 Aviation type oil 1000 The oil obtained had the following characteristics:

Density at 15 C.

p.379 Flash'point, open cup 258 C. Yiscosity, Saybolt Universal at 988 C 110 Viscosity index, Dean and Davis 110 .Solidifying point 30 C. Conradson carbon (residue) 0.24 number 10.8

Example 2 In recycling all the productsboiling below the aviation oil fraction the reaction tends to an "equilibrium in'the following proportions Charge: 7 Kilograms Fresh benzenefi 40 Recycled products 1440 Cracking distillate 1000 Aluminum chloride 40 Products obtained:

Sludge (without aluminum chloride) Recycled products (boiling below 220 C.

under 3 mm. of mercury pressure) 1440 Aviation oil (boiling above 220 C'. under 3 mm. mercury pressure) The consumption of the products per ton of aviation oil are, therefore, as'iollows;

Consumption: Kilograms Benzene 54 Cracking distillate 1350 Aluminum chloride 54 Products obtained: 7

Aviation oil 1000 The characteristics of the oil obtained were as follows:

Sludge (without aluminum chloride) Comparison of the Examples 1 and 2 clearly shows the remarkable advantages of recycling.

The improvement of the iodine number which seems to be due to the decantation of the aluminum chloride sludge is improved in the presenceof recycled products and is particularly remarkable.

1 Example 3 'In this example (carried on the semi-industrial scale) the overhead products boiling in the range of light gasolines up to 150 C. were rejected and the productsboiling between 150 C., at atmospheric pressure, and 210 C., under the pressure of 3 mm. of mercury, were recycled.

Charge: Kilograms Benzene 310 Recycled products 1400 Cracking distillate 1000 Aluminumchloride 40 Products obtained:

Sludge 53 Overhead products 218 Recycled products 1400 Oil (boiling at about 210 C. under 3 mm. of mercury pressure) 650 The consumption and products were as follows:

Consumption: Kilograms Benzene 460 Cracking distillate 1540 Aluminum chloride Products:

Sludge 81 Overhead products 335 Oil 1000 I Characteristics of the oil:

Density at 15 C. 0.887

Flash point 262 C. Viscosity, Saybolt at 988 C. 121.8 Viscosity index, Dean and Davis 108 solidifying point -30 C. Iodine number 4 The invention has been described by giving specific examples without being limited, necessarily to such examples. It is intended to cover 0bvious equivalents and variants conforming to the spirit of the invention without necessarily being restricted to the particular products or conditions given above. The proportions of aromatic hydrocarbon to olefin containing fraction may vary from about 1 to 30 to as much as 1 to 3. The type and quantity of catalyst, and the reaction conditions also can be varied within reasonable limits.

' What is claimed is:

An improved processior the production of a synthetic lubricant which comprises simultaneously alkylating and polymerizing about 50 parts by weightof; benzene withabout 200 parts by weight fa cracked distillate in the presence of about I parts by weight of aluminum chloride at a temperature of about 50 C. for about 5 hours in'a reaction zone, allowing the temperature tor-ii v to one within a range of from C. toabout 1 10 C. for about 2 hours to obtain an alkylafiflglfim merized reaction product, treatingjsaid action productwith a decolorizing clay in the sence of steam, distilling said thetic l mating oil fraction having an iodine n; number'of less than it and alight lower boiling 2,518,529 5 6 fraction, recycling said light fraction to said re- REFERENCES CITED action zone, charging to said reac ion zone fresh 1 benzene cracking distillate and aluminum chlogg ifi g f are of record m the ride until there exists in said reaction zone a mix- 5 p ture comprising approximately 4 parts by weight 5 UNITED STATES PATENTS of benzene, 144 parts by weight of recycled frac- Number Name Dat tion, 100 parts by weight of cracking distillate 2,13 ,775 Towne Nov, 29, 1933 and 4 parts by weight of aluminum chloride, and 4 5 3 m g 1; 1 1 27 93 reacting said charged materials to obtain a 860- 2,410,335 Li ov, 12, 1945 0nd synthetic lube fraction having an iodine num- 10 2,413,161 Zerner et al Dec. 24, 1946 her of less than 10. 2,435,483 Vose Feb. 3, 1948 ROGER BOUX DE CASSON. 2,456,119 Friedman et a1. Dec. 14, 1948 LUCIEN HEMMER. 2,475,970 Lieber et a1 July 12, '1949