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

Participants

Reaction Conditions

Reaction Steps

A 5-L autoclave made of Hastelloy (HC22) was charged with 552 g of pyromellitic acid, 200 g of a catalyst formed by supporting Rh on activated carbon (available from N.E. Chemcat Corporation) and 1656 g of water. The interior of the autoclave was replaced with a hydrogen gas while stirring the contents. Then, 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. After replacing the hydrogen gas in the autoclave with nitrogen gas, the reaction product solution was discharged from the autoclave. The reaction product solution was filtered while it was hot to separate the catalyst. The filtrate was concentrated by distillation under reduced pressure using a rotary evaporator to evaporate off water, thereby precipitating crystals. The precipitated crystals were collected by a solid-liquid separation at room temperature, and then, dried to obtain 481 g of 1,2,4,5-cyclohexanetetracarboxylic acid (yield: 85.0%).

Provenance & Evidence