2-Phenylphenolの水素添加と水素添加物の化学的研究 (第3報)

2-Phenylphenolの中圧液相水素添加

抄録

In the previous paper, the high pressure liquid-phase hydrogenation of 2-phenylphenol (initial hydrogen pressure, 100-130kg./cm²) was reported. It has been observed that these harsh conditions are not suitable to examine the course of reaction since the hydrogenation proceeds further in such case. Therefore, in this paper medium pressure liquid-phase hydrogenation (initial hydrogen pressure 50-90kg./cm², hydrogen mole ratio, 6.8-12) was investigated and the important factors which influence the reaction and the products obtained were examined. Among eighteen tested catalysts, three nickel type reduction catalysts were found to be suitable. Copper-zinc catalyst showed less hydrogenation activity and among the reduction products, large amounts of 2-phenylcyclohexanone and 2-cyclohexylcyclohexanone were found. The following relationship between solvent used and hydrogenation speed were established: tert-butanol; propanol; iso-butanol; butanol; sec-butanol; methanol=259; 182; 129; 113; 108; 100, respectively. In the case of hydrogenation of 2-phenylphenol and its related compounds the reaction was proceeded more by the pressure than the temperature. The hydrogenation began from a pressure of about 80kg./cm², irrespective of the kind of solvent and compound used. The formation of stereoisomers during the reaction was also studied. Similar to that of high pressure liquid-phase hydrogenation, in medium hydrogen pressure liquid-phase, cis-isomer rearranged into trans-isomer (DL-trans-2-cyclohexylcyclohexanol), depending upon the stage of hydrogenation.