4,5-Dichlorophthalic acid → 4,5-Dichlorophthalic anhydride

HRID 1708936Notes

Reaction equation

HRID 1708936 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:12]([OH:14])=[O:13])[C:5](=[CH:9][C:10]=1[Cl:11])[C:6]([OH:8])=O>C(OC(=O)C)(=O)C>[Cl:11][C:10]1[CH:9]=[C:5]2[C:6](=[O:8])[O:14][C:12](=[O:13])[C:4]2=[CH:3][C:2]=1[Cl:1]

Participants

3

Reactant 1

HCID 926004,5-Dichlorophthalic acid

Product 1

HCID 703344,5-Dichlorophthalic anhydrideYield 87.4%

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent

Procedure

A suspension of 4,5-dichlorophthalic acid [(XVII), X=4--Cl, Y=5--Cl, 50.0 g, 0.213 mol] and acetic anhydride (70 mL) was heated to reflux until dissolution occurred. A distilling head was then attached and 30 mL of distillate was removed. The solution was cooled to room temperature whereupon a precipitate appeared. This solid was filtered, washed with anhydrous ether and dried in vacuo to provide the product (40.4 g, 87%) as a tan solid, m.p. 189°-192° C.

Workup

  1. temperaturewas heated
  2. temperatureto reflux until dissolution
  3. custom30 mL of distillate was removed
  4. filtrationThis solid was filtered
  5. washwashed with anhydrous ether
  6. customdried in vacuo

Sources & evidence

ORD record
ord-404523b8b2f54211981e1c04b72155fb
Source dataset
uspto-grants-1990_08
Patent number
US04946858

Reaction notes

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