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

HRID 237183

Reaction equation

HRID 237183 reaction equation
[C:1]([OH:18])(=[O:17])[C:2]1[C:3](=[CH:7][C:8](=[C:12]([CH:16]=1)[C:13]([OH:15])=[O:14])[C:9]([OH:11])=[O:10])[C:4]([OH:6])=[O:5].[H][H]>[Rh].O>[CH:8]1([C:9]([OH:11])=[O:10])[CH2:7][CH:3]([C:4]([OH:6])=[O:5])[CH:2]([C:1]([OH:18])=[O:17])[CH2:16][CH:12]1[C:13]([OH:15])=[O:14]

Participants

5

Reactant 2

HCID 6961Pyromellitic AcidHCID 178418361HCID 178418361, compound4×

Product 1

HCID 28349461,2,4,5-Cyclohexanetetracarboxylic AcidYield 85.1%

Reagents, catalysts & solvents 2

HCID 23948RhodiumCatalystHCID 962WaterSolvent

Conditions

Temperature
60 °C

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%).

Workup

  1. filtrationwas filtered while it
  2. customto separate the catalyst
  3. concentrationThe filtrate was concentrated
  4. customby evaporating water under reduced pressure
  5. customa rotary evaporator
  6. customto precipitate crystals
  7. customThe precipitated crystals were separated by solid-liquid separation at room temperature
  8. customdried

Sources & evidence

ORD record
ord-8ddcf2cd89834c66bb4be89b8a8530c1
Source dataset
uspto-grants-2014_02
Patent number
US08642181B2

Linked notes

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