US 2497138 A
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Patented Feb. 14, 1950 METHOD OF PURIFYING SULFURIZED HYDROCARBON PRODUCTS Dilworth T. Rogers, Summit, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing.
The present invention relates to sulfurized hydrocarbon products which are especially useful as addition agents for lubricants and relates more particularly to a method of purifying such products.
Addition agents for lubricating oils have been previously made by sulfurizing fats, fatty oils and hydrocarbon materials with free sulfur by heating at an elevated temperature, and while such products have been used for many years they are not fully satisfactory because the sulfurization is accompanied by side reactions such as cracking, polymerization and the like, which give rise to inactive constituents and darkly colored bodies some of which may be merely useless while others are decidedly objectionable.
It is known that sulfurized materials of a more satisfactory character can be formed by sulfurizing olefin hydrocarbons, especially the polymers of low molecular weight olefins, and more specifically the polymers of propylene, the butylenes and amylenes. These materials may be sulfurized by heating with free sulfur, but it has been found that a more satisfactory product from the standpoint of color, oil solubility, lack of copper staining tendency and odor can be obtained by sulfurizing with a sulfur halide, such as sulfur monochloride or sulfur dichloride. Unfortunately, it is difficult to free theproduct from a considerable proportion of the halogen. An amount of halogen up to or greater will re main in the sulfurized product even after heating for long periods of time. For certain purposes such amounts of halogen are very objectionable, particularly where corrosion is to be avoided.
In accordance with the present invention an aliphatic or cycloaliphatic hydrocarbon which has been sulfurized by means of a sulfur halide can be dehalogenated with little difficulty by merely heating such product, containing a hydrogen halide impurity, with a secondary or tertiary saturated monohydric aliphatic alcohol having 4 to 16 carbon atoms per molecule. Advantageous results may be obtained by employing quantities of the said alcohols ranging from about 0.1 to about 2 molecular proportions for each molecular proportion of the sulfurized hydrocarbon product. The temperature range found to be most satisfactory is from about 100 to about 320 F. (40 to 160 0.), but the most desirable range has been found to be from 175 to 285 F. (80 to 140 0.). It will generally be found convenient to conduct the operation at the refluxing temperature of the alcohol.
It is believed that the action of the alcohol Application October 29, 1947, Serial No. 782,955
in effecting dehydro-halogenation is mainly catalytic. However, it is possible that a small proportion of the alcohol may enter into chemical combination with the sulfurized hydrocarbon.
The hydrocarbon materials which may be sulfurized by sulfur halides and then reduced in halogen content by the method of the present invention include any aliphatic or alicyclic hydrocarbons containing an unsaturated carbonto-carbon linkage. This group of materials includes the olefins, e. g., propylene, butylenes, diisobutylenes, triisobutylenes, the codimer of isobutylene and n-butylene, also cracked gasoline fractions, cracked paraflin wax, viscous olefin polymers such as medium or high molecular weight polybutene, cyclopentene, cyclohexene, butadiene, pentadiene, isoprene and the like. Likewise the process may be applied to compounds having acetylenic linkages, CEC. Olefins of less than 4 carbon atoms are not generally employed in preparing sulfurized lubricating oil additives, although products prepared from such olefins may be purified by the method of the present invention. Derivatives of the above described compounds containing various substituent groups and atoms may be used to advantage since the substituent groups normally do not interfere with sulfurization reaction or the purifying process herein described. Such substituted derivatives may include olefins having attached aromatic nuclei, halogen atoms, nitro groups, etc.
For the preparation of the sulfurized hydrocarbons and the like the most suitable sulfur halides are sulfur dichloride and monochloride, especially the latter. The olefinic material and sulfur halides are generally reacted in ratios of olefinic material to sulfur halide within the range from about 3:1 to 1: 1 molal ratio. Higher ratios of olefinic material are sometimes used when a portion of the same is to serve as a solvent to be removed later as unreacted material. The temperatures which have been found most satisfactory for this reaction are from about to F. (20 to 50 C.), but the method may be carried out at considerably higher or lower temperatures if desired. Catalysts are not required.
In the dehalogenating process of the present invention the sulfurized product is merely heated in the presence of the alcohol under the conditions specified above until substantial dehalogenation is brought about. The heating is conveniently carried out under refluxing conditions. The greater portion of the dehalogenation is accomplished within a short time, of the order of one-half hour or less, although a relatively lim- 3 lted further purification will be brought about by further heating to a period of, say, three to four hours.
The alcohols which may be employed for the purpose of the present invention are the secondary and tertiary saturated monohydric aliphatic alcohols containing from 4 to 16 carbon atoms per molecule. Particularly suitable examples of these alcohols are sec.-butyl alcohol, tert.-butyl alcohol, isoamyl alcohol, 2-ethyl-hexy1 alcohol and methylcyclohexanol.
The following example illustrates an application of the present invention to the purification of a sulfurized diisobutylene; but this example is not to be considered as limiting the scope of the invention in any manner.
Example 750 g. diisobutylene (25% excess) was placed in a reaction vessel provided with stirrer and reflux condenser and 313 g. sulfur monochloride was added gradually over a period of one hour while stirring and maintaining a temperature not greater than 130 F. After the addition of the sulfur monochloride had been completed the stirring was continued for two hours longer. The reaction product was found to contain 10.5% chlorine. 150 g. of this sulfurized product and 15 g. of 2-ethylhexyl alcohol were placed in a reaction vessel provided with a refluxing condenser and heated at 230380 F. (refluxing temperature) for 4 hours. The product was then distilled under vacuum at to 20 mm. mercury pressure and 240 F. temperature to remove the excess diisobutylene. The final product was found to contain 2.0% chlorine.
The present invention is not to be considered as limited by any of the specific embodiments or examples herein disclosed, but is to be limited solely by the terms of the appended claims.
' 1. A method of dehalogenating a sulfurized product which has been obtained by reacting a compound of the class consisting of aliphatic and alicyclic hydrocarbon compounds containing an unsaturated carbon-to-carbon linkage with a sulfur halide which comprises heating 1 molecular proportion of said sulfurized product in the presence of about 0.1 to about 2 molecular proportions of a member of the group consisting of secondary and tertiary saturated monohydric aliphatic alcohols having 4 to 16 carbon atoms per molecule at a temperature of about 100 to about 320 F.
2. A method of dechlorinating a sulfurized olefin which has been obtained by reacting an olefin with a sulfur chloride, which comprises heating 1 molecular proportion of said sulfurized olefin in th presence of about 0.1 to about 2 molecular proportions of a member of the group consisting of secondary and tertiary saturated monohydric aliphatic alcohols having 4 to 16 carbon atoms per molecule at a temperature of about to about 320 F.
3. A method according to claim 2 in which the sulfurized olefin is sulfurized diisobutylene.
4. A method according to claim 2 in which the alcohol is a secondary aliphatic alcohol.
5. A method according to claim 2 in which the alcohol is 2-ethylhexyl alcohol.
6. A method of dechlorinating sulfurized diisobutylene which has been formed by reacting diisobutylene with sulfur monochloride which comprises heating 1 molecular proportion of said sulfurized diisobutylene in the presence of about 0.1 to about 2 molecular proportions of 2-ethylhexyl alcohol at a temperature of about 100 to about 320 F.
7. A method of dechlorinating sulfurized diisobutylene which has been obtained by reacting diisobutylene with sulfur monochloride which comprises heating 1 molecular proportion of said sulfurized diisobutylene in the presence of about 0.1 to about 2 molecular proportions of methylcyclohexanol at a temperature of about 100 to about 320 F.
8. A method of dechlorinating sulfurized diisobutylene which has been obtained by reacting diisobutylene with sulfur monochloride which comprises heating said sulfurized diisobutylene with about 10% by weight of 2-ethylhexyl alcohol at a temperature of about 230 to 280 F. for a period of about 4 hours.
DILWORTH T. ROGERS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,210,563 Andrusson Aug. 6, 1940 2,356,073 May Aug. 15, 1944 2,356,074 May Aug. 15, 1944 2,425,824 Peters et a] Aug. 19, 1947 FOREIGN PATENTS Number Country Date 283,877 Great Britain 1928