A NOVEL SYNTHESIS OF CYCLOHEXANOL DERIVATIVES BY THE CATALYTIC-HYDROGENATION OF BENZENE WITH ACID ADDITIVES

The hydrogenation of benzene over a platinum group metal in the presen ce of various strong acids was carried out. Cyclohexanol derivatives ( C6H11X, X = OH, OAc, Cl, Br) were found to be produced by the catalyti c hydrogenation of benzene with acid additives. The following two sequ ences of adsorption strength were observed between platinum metals (ad sorbent) and additive reagents (adsorbate): Ru much-greater-than Rh > Pd > Ir > Pt (I) and HI, HCOOH much-greater-than HBr > HCl much-greate r-than AcOH, H2O. (II) When a weak adsorbate, such as acetic acid or w ater, was used as an additive reagent, ruthenium, the strongest adsorb ent, exhibited the best selectivity. When hydrogen chloride, a strong adsorbate in the sequence (II), was used an additive reagent, palladiu m or rhodium, moderately strong adsorbent, exhibited excellent selecti vity. By the reaction of 2 ml of benzene, 5 ml of 35% HCl and 0.2 g of 5% Pd/SiO2, under 10 atm-G (P atm-G = 1.013(P + 1) x 10(5) Pa) hydrog en at 100-degrees-C for 20 h, 8.4% of the yield of chlorocyclohexane w as obtained at 64.2% of the selectivity (13.1% of the conversion of be nzene).