Optimization of Catalytic Reaction for Synthesis of 2-Methyl-4-methoxydiphenylamine

2-Methyl-4-methoxydiphenylamine 합성을 위한 촉매반응의 최적화

  • Cho, Jeong-Woo (School of Chemical Engineering & Technology, Yeungnam University) ;
  • Kim, Eun-Seok (School of Chemical Engineering & Technology, Yeungnam University) ;
  • Kim, Kiseok (School of Chemical Engineering & Technology, Yeungnam University) ;
  • Kim, Seong-Hoon (Department of Dyeing & Finishing, Kyungpook National University)
  • 조정우 (영남대학교 화학공학 및 공업화학부) ;
  • 김은석 (영남대학교 화학공학 및 공업화학부) ;
  • 김기석 (영남대학교 화학공학 및 공업화학부) ;
  • 김성훈 (경북대학교 염색공학과)
  • Received : 1998.10.09
  • Accepted : 1998.12.22
  • Published : 1999.04.10

Abstract

Reaction mechanism was elucidated and reaction condition were optimized for the catalytic reaction synthesizing 2-methyl-4-methoxy-diphenylamine (MMDPA) which is an intermediate of Fluoran heat-sensitive dyestuff. Reactants consisted of 2-methyl-4-methoxyaniline (MMA), 3-methyl-4-nitroanisole (MNA), and cyclohexanone, and 5 wt % Pd/C was used as a catalyst. Experiments were run in an open slurry reactor equipped with reflux condenser, and products were analyzed by means of GC/MS and NMR. MMDPA yield of 90 mole % could be obtained after reaction time of 8~10 hours under the optimal reaction conditions comprising the reaction mass composition of MMA : MNA : cyclohexanone = 1 : 2 : 150 based on MMA input of 0.01 gmoles in xylene solvent, reaction temperature of $160^{\circ}C$, and catalyst amount of 0.5 g. It was found that the rate-determining step of overall reaction was dehydrogenation of the intermediate product obtained from condensation of MMA and cyclohexanone. Overall reaction rate and MMDPA yield were enhanced owing to hydrogen transfer reaction by introducing MNA together with MMA in the reaction mass. Excess cyclohexanone in the reaction mass played an important role of promoting the condensation of MMA and cyclohexanone.

Keywords

2-Methyl-4-methoxydiphenylamine;Rate-determining Step;Hydrogen-transfer reaction;Cyclohexanone

Acknowledgement

Supported by : 한국과학재단

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