| 摘要 |
Mercaptans and sulphides are prepared by treating an olefinic material, viz. hydrocarbons or halogenated hydrocarbons containing one or more aliphatic double bonds, with hydrogen sulphide in the presence of a Friedel-Crafts' catalyst, either the catalyst or the olefinic material being pretreated with hydrogen sulphide before the catalyst is contacted with the olefinic material. The catalyst may be pretreated with hydrogen sulphide before adding to the reaction mixture or may be added while hydrogen sulphide is bubbled through the liquid olefinic material. The olefin is preferably in the liquid phase, temperatures from somewhat above normal, say 90 DEG C., down to -80 DEG C. being used, and atmospheric pressure or above. Suitable catalysts are halides such as chloride or bromides of Al, Sb, B, Sn, Ti, Zn, In, mixed halides, oxyhalides, hydrated halides or complexes with alcohols or ethers, hydrogen fluoride, and aluminium amalgam. The use of stannic chloride is covered in Specification 602,303. The olefinic materials include primary, secondary, and tertiary olefines, e.g. isobutene, octene-1 or -2, trimethyl ethylene di-isobutene, copolymers of iso- and n-butenes, diamylene, tri- and tetra-isobutene, turpentine, and caprylene, polyolefins such as butadiene, isoprene, 2-methyl pentadiene, and myrcene, and mixtures derived from cracked petroleum and the hydrolysis of acid extracts of C4 cut. The liquid olefin may be contacted in a packed column with hydrogen sulphide gas containing a gaseous catalysts such as BF3 or HF. Non-gaseous catalyst may be dissolved in a solvent such as methyl or ethyl chloride or higher boiling halides, nitrobenzene, carbon disulphide, aliphatic or aromatic hydrocarbons, and the solution treated with hydrogen sulphide. The products may be steam distilled or fractionated and the mercaptans extracted with alkali. They are of use as modifiers in the preparation of synthetic rubber and as corrosion preventives in lubricants. In examples: (1) and (2) di-isobutene is dropped down a packed glass tube down which is passed a stream of H2S and BF3, and di-isobutyl mercaptan recovered from the product; (3) H2S and BF3 are bubbled into di-isobutene in a batch operation; (4) or (5) the apparatus of (1) is used for isobutene which is condensed by external cooling, tertiary butyl mercaptan being obtained; (6) diamylene is converted similarly; (7) to (14) tri-isobutene, turpentine, tetraisobutene, caprylene, cyclohexene, dipentene, 2-methyl pentadiene, and allyl bromide are treated with H2S and BF3 to yield the corresponding mercaptans, allyl bromide, for example, giving a -bromisopropyl mercaptan. In the case of 2-methyl pentadiene temperature rises to 125 DEG C.; (15) hydrogen sulphide is bubbled into di-isobutene while sprinkling in aluminium chloride; (16) the catalyst, chloride of Al Sb, Zn, or Ti or HF, is added to CS2 and H2S bubbled in, di-isobutene then being slowly added. Specification 532,676 also is referred to. |
