Reaction #324366

Reaction equation

1,2,4,5-cyclohexanetetracarboxylic acid

acetic anhydride

→

1,2,4,5-cyclohexanetetracarboxylic dianhydride

Yield 96.7%

Conditions

Workup

1. 1
   Otherequipped with a Dimroth condenser
2. 2
   TemperatureThe temperature was raised to the refluxing temperature of the solvent under a nitrogen gas atmosphere
3. 3
   Temperatureto reflux for 10 min
4. 4
   Otherwas decreased to room temperature
5. 5
   workup.STIRRINGunder stirring
6. 6
   Otherto precipitate crystals
7. 7
   OtherThe precipitated crystals were separated by solid-liquid separation
8. 8
   Otherdried
9. 9
   Otherto obtain primary crystals
10. 10
    OtherThe mother liquor after separation
11. 11
    Concentrationwas concentrated under reduced pressure
12. 12
    Othera rotary evaporator
13. 13
    Otherto precipitate crystals
14. 14
    OtherThe precipitated crystals were separated by solid-liquid separation
15. 15
    Otherdried
16. 16
    Otherto obtain secondary crystals

Procedure

Subsequently, 450 g of the obtained 1,2,4,5-cyclohexanetetracarboxylic acid and 4,000 g of acetic anhydride were charged into a 5-L glass separable flask equipped with a Dimroth condenser. The inner atmosphere of the reactor was replaced with nitrogen gas under stirring. The temperature was raised to the refluxing temperature of the solvent under a nitrogen gas atmosphere to allow the solvent to reflux for 10 min. After that, the temperature was decreased to room temperature under stirring to precipitate crystals. The precipitated crystals were separated by solid-liquid separation and dried to obtain primary crystals. The mother liquor after separation was concentrated under reduced pressure using a rotary evaporator to precipitate crystals. The precipitated crystals were separated by solid-liquid separation and dried to obtain secondary crystals. In total of the primary and secondary crystals, 375 g of 1,2,4,5-cyclohexanetetracarboxylic dianhydride was obtained (yield of the dianhydride: 96.6%).

Source