| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject compound effectively, without producing by- products and causing the problem of the corrosion of an apparatus, and useful as an intermediate, etc., for a liquid crystal through the hydrogenation of the aromatic ring of a specific 4-substituted benzoic acid under a specific condition. SOLUTION: This trans-4-substituted cyclohexanecarboxylic acid of formula II (e.g.; trans-4-n-propylcyclohexanecarboxylic acid) is obtained by the catalytic hydrogenation of a 4-substituted benzoic acid of formula I (R is a 1-18C alkyl or alkoxyl) (e.g.; 4-n-propylbenzoic acid) in an aqueous alkaline solution (e.g.; sodium hydroxide) in the presence of a hydrogenation catalyst (e.g.; carbon loaded with ruthenium) at 50-150 deg.C to hydrogenate the aromatic ring of the benzoic acid, then without filtering the hydrogenating catalyst, adjusting the hydrogen pressure in the reaction system to atmospheric pressure, and then heating the reaction system to 200-400 deg.C. Further, it is preferable to adjust the hydrogen pressure in the reaction system to the atmospheric pressure, next replace the hydrogen gas in the system with an inert gas and then heat at 200-400 deg.C in the same reaction system. |
