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

Participants

Reaction Conditions

Reaction Steps

A 5-L Hastelloy (H22) autoclave was charged with 552 g of pyromellitic acid, 200 g of a catalyst, rhodium carried on activated carbon, available from N.E. Chemcat Corporation, and 1656 g of water. The inner atmosphere of the reactor was replaced with nitrogen gas under stirring. After replacing the inner atmosphere of the reactor with hydrogen gas, the hydrogen pressure was adjusted to 5.0 MPa and the temperature was raised to 60° C. While maintaining the hydrogen pressure at 5.0 MPa, the reaction was allowed to proceed for 2 h. Then, after replacing the hydrogen gas with nitrogen gas, the reaction product solution taken out of the autoclave was filtered while it was still hot to separate the catalyst. The filtrate was concentrated by evaporating water under reduced pressure using a rotary evaporator to precipitate crystals. The precipitated crystals were separated by solid-liquid separation and dried to obtain 481 g of 1,2,4,5-cyclohexanetetracarboxylic acid (yield: 85.0%).

Provenance & Evidence