22-02-1967 дата публикации
Номер: GB1059386A
Unsaturated hydrocarbons are selectively hydrogenated in a liquid containing hydrogen ions and in the presence of a finely-divided metallic catalyst, the electrochemical hydrogen reference potential being measured during hydrogenation and the hydrogenation being stopped when the change in the reference potential with respect to time reaches or approximates to a maximum value at the prevailing pH value. Hydrogenation is carried out either by saturating the catalyst with hydrogen in a shaker prior to the addition of the organic compound, or the organic compound/catalyst mixture is put into an autoclave and the hydrogen forced in. For suitable catalysts, solvents, electrolytes and buffers (see Division B1). Examples of suitable unsaturated compounds are cyclic, mono- or polyunsaturated hydrocarbons, particularly cycloolefins and cyclo-diolefins with 5-12 C atoms, phenylacetylene; 1,3,5-triethinyl benzene, cyclohexene, cyclooctadiene. The following hydrogenations are exemplified. Example 3, one double bond in cyclooctadiene, and cyclohexene; Example 10, phenylacetylene to phenylethylene (i.e. styrene).ALSO:The electrochemical hydrogen reference potential is measured during the hydrogenation of C-C multiple bonds in organic compounds in a liquid containing hydrogen ions and in the presence of a finely divided metallic catalyst, and selective hydrogenation is effected by stopping the hydrogenation when the change in the reference potential with respect to time reaches or approximates to a maximum value at the prevailing pH value. Hydrogenation is carried out either by saturating the catalyst with hydrogen in a shaker prior to the addition of the organic compound, or the organic compound/catalyst mixture is put into an autoclave and the hydrogen forced in. For suitable catalysts, solvents, electrolytes and buffers (see Division B1). Compounds that may be hydro-genated are aralkyl compounds having acetylenic side chains, particularly those having a benzene radical and one ...
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