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

Participants

Reaction Conditions

Reaction Steps

A 5 L-capacity Hastelloy (HC22) autoclave was charged with 552 g of pyromellitic acid, 200 g of a catalyst prepared by supporting rhodium on activated carbon (available from N.E. Chemcat Corp.) and 1656 g of water, and while stirring the contents of the autoclave, an interior of the reaction vessel was replaced with a nitrogen gas. Then, the interior of the reaction vessel was replaced with a hydrogen gas until a hydrogen pressure in the reaction vessel reached 5.0 MPa and an inside temperature of the reaction vessel was raised up to 60° C. The contents of the autoclave were reacted for 2 hours while maintaining a hydrogen pressure in the autoclave at 5.0 MPa. The hydrogen gas in the reaction vessel was replaced with a nitrogen gas, and the obtained reaction solution was withdrawn from the autoclave. The thus obtained reaction solution was subjected to hot filtration to separate the catalyst therefrom. The resulting filtrate was concentrated by evaporating water therefrom under reduced pressure using a rotary evaporator to precipitate crystals, and the resulting slurry was subjected to solid-liquid separation at room temperature to separate the precipitated crystals therefrom. The thus obtained crystals were dried to obtain 481 g of 1,2,4,5-cyclohexane tetracarboxylic acid (yield: 85.0%).

Provenance & Evidence