2-Methyl-3'-hydroxydiphenylamine was synthesized from the mixture of 3-aminophenol, 3-nitrophenol, and 2-methylcyclohexanone in the presence of Pd/C catalyst. The optimum composition of the reaction mixture was determined for maximum yield of the diphenylamine derivative : with the molar ratio of 3-aminophenol : 3-nitrophenol fixed at 1 mmol : 2 mmol, the relative molar amounts of 2-methylcyclohexanone were varied between 3 and 96. At the optimum composition the amounts of Pd/C catalyst were varied threefold in order to investigate the effect of Pd on the product yield. The results obtained from the reaction mixture containing 1 mmol of 3-aminophenol were satisfactorily reproduced for the reaction mixture containing more than 10 mmol of 3-aminophenol. The formation of this diphenylamine derivative could be interpreted using the mechanism for the catalytic synthesis of 2-methyl-4-methoxydiphenylamine which we had optimized previously.

2-Methyl-3'-Hydroxydiphenylamine Optimum Composition of Reaction Mixture Maximum Yield of Diphenylamine Derivative Effect of Pd Mechanism for Catalytic Synthesis

Akamatsu N, "Improved Preparation of Diphenylamine Derivatives Comprising Reaction of Nitrobenzenes with Anilines and Cyclohexanone in Presence of Palladium Catalyst," Japanese Patent, 05-117214 (1993)
Cho JW, Kim KS, Lee TJ, Kim JC, Kim DH, Theor. Appl. Chem. Eng., 1, 89 (1995)
Elmar RS, Somerville NJ, "Preparation of Hydroxy Substituted Diarylamines," U.S. Patent, 3,450,764 (1969)
Friedrich WC, Heinz UB, "Process for the Preparation of Hydroxydiphenylamines," U.S. Patent, 4,265,833 (1981)
Industry Research Institute Report, Korea (1990)
Kim KS, Lee TJ, Kim JC, Kim DH, "Optimization of Catalytic Synthesis of Diphenylamine Derivative," Proceedings of 7th Japan-China-USA Symp. on Catalysis, Tokyo, Japan, 41 (1995)
Nagata T, Kusuda C, Wada M, "Process for the Preparation of Diphenylamine of Nucleus-Substituted Derivative Thereof," U.S. Patent, 5,545,752 (1996)
Otto IK, Gerhard D, Hans JB, "Process for Preparation of Diphenylamine," U.S. Patent, 5,338,885 (1994)
Otto IK, Gerhard D, Hans JB, "Process for Preparing Diphenylamine," U.S. Patent, 5,344,987 (1994)