GB361341A - Process for the manufacture of monomolecular reaction products of unsaturated hydrocarbons of the butadiene series with sulphur dioxide - Google Patents

Abstract

Monomolecular reaction products are obtained by treating butadiene hydrocarbons with sulphur dioxide in the presence of small quantities of substances having a stabilizing action on polymerizable hydrocarbons having olefinic double bonds. Examples of such anticatalysts are phenols, especially polyhydric phenols such as hydroquinone, pyrocatechol, and pyrogallol, amines, copper, and salts of copper. The reaction may be carried out in closed vessels in aqueous solution, or gaseous sulphur dioxide may be forced with a mixture of the diolefinic hydrocarbon and the anticatalyst. Inert solvents, for example, hydrocarbons such as benzene, may be present. Diolefinic hydrocarbons which may be treated are butadiene-1 : 3, 2-methylbutadiene-1 : 3, 2 : 3-dimethylbutadiene-2 : 3, 1-phenylbutadiene-1 : 3, 2 : 3-diphenylbutadiene-1 : 3, 2-ethylbutadiene-1 : 3, and 2-isopropylbutadiene-1 : 3. Examples are given, in one of which butadiene-1 : 3 mixed with one per cent of hydroquinone is treated with liquid sulphur dioxide at room temperature for eight days. The crystalline paste formed is dissolved in benzene, small quantities of high-molecular products removed by filtration and the monomolecular product is precipitated in the form of crystals by the addition of petroleum ether. The substance is presumably dihydrothiophene sulphone. When smaller quantities of the anticatalyst are used, larger quantities of high-molecular products are obtained which can be separated by their insolubility in suitable solvents, such as benzene, alcohol, chloroform, and water. Other examples describe the formation of the monomolecular sulphones corresponding to butadiene-1 : 3, 2 : 3-dimethylbutadiene-1 : 3, and isoprene using as anticatalysts pyrogallol, pyrocatechol, copper powder, copper oleate, 1 : 8-naphthylenediamine, and NN<1>-diphenyldiaminoethane. When isoprene is treated with sulphur dioxide in presence of pyrogallol, high-molecular sulphones are also formed, which can be separated by their insolubility in water or benzene.