Reaction #324365

Reaction equation

hydrogen

pyromellitic acid

hydrogen

hydrogen

hydrogen

→

1,2,4,5-cyclohexanetetracarboxylic acid

Yield 85.1%

Solvents

water

Conditions

Workup

1. 1
   Filtrationwas filtered while it
2. 2
   Otherto separate the catalyst
3. 3
   ConcentrationThe filtrate was concentrated
4. 4
   Otherby evaporating water under reduced pressure
5. 5
   Othera rotary evaporator
6. 6
   Otherto precipitate crystals
7. 7
   OtherThe precipitated crystals were separated by solid-liquid separation at room temperature
8. 8
   Otherdried

Procedure

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%).

Source