Pyromellitic Acid → 1,2,4,5-Cyclohexanetetracarboxylic Acid

Participants

Reaction Conditions

Reaction Steps

A 5-L Hastelloy (HC22) autoclave was charged with 552 g of pyromellitic acid, 200 g of a catalyst of Rh supported on activated carbon (available from N.E. Chemcat Corporation) and 1656 g of water, and then the inner atmosphere was replaced with nitrogen gas while stirring the contents. Then, the inner atmosphere was replaced with hydrogen gas and the temperature was raised to 60° C. under a hydrogen pressure of 5.0 MPa. The reaction was continued for 2 h while maintaining the hydrogen pressure at 5.0 MPa. After replacing the hydrogen gas in the autoclave with nitrogen gas, the reaction product solution was taken out of the autoclave and filtered hot to separate the catalyst. The filtrate was concentrated under reduced pressure using a rotary evaporator to precipitate crystals. The precipitated crystals were subjected to solid-liquid separation and then dried to obtain 481 g of 1,2,4,5-cyclohexanetetracarboxylic acid (yield: 85.0%).

Provenance & Evidence