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, that is, rhodium carried on activated carbon, available from N.E. Chemcat Corporation, and 1,656 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 in the reactor 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 hours. Then, after replacing the hydrogen gas in the reactor 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 at room temperature and dried, thereby obtaining 481 g of 1,2,4,5-cyclohexanetetracarboxylic acid (yield: 85.0%).

Provenance & Evidence