4-Hydroxybenzoic Acid → Benzoic acid, 4-(acetyloxy)-

HRID 1446784Notes

Reaction equation

HRID 1446784 reaction equation
[OH:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][CH:3]=1.[C:11](OC(=O)C)(=[O:13])[CH3:12]>>[C:11]([O:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[CH:4][CH:3]=1)(=[O:13])[CH3:12]

Participants

3

Reactant 2

HCID 1354-Hydroxybenzoic AcidHCID 7918Acetic Anhydride

Product 1

HCID 16865Benzoic acid, 4-(acetyloxy)-

Conditions

Temperature
150 °C

Procedure

In a glass flask, were placed under a nitrogen stream 1,380 g of p-hydroxybenzoic acid and 1,120 g of acetic anhydride. The mixture was refluxed at 150° C. for 2 hours and then the temperature was raised while removing acetic acid by distillation. When the temperature reached 230° C., the p-acetoxybenzoic acid formed by acetylation was transferred into a double-arm kneader which had been heated to 230° C. At this stage, the p-acetoxybenzoic acid was liquid. While agitating at low speed, the temperature of this liquid was raised to 330° C. taking a period of one hour. When the temperature had reached 310° C., an increase in torque was observed. Polymerization was continued with increased speed of agitation until the mixture in the kneader was transformed into powder. 100 Grams of the powder were tested for particle diameter. It was found that 73% of the sample had a particle diameter of 0.1 mm or less. The polymerization was continued at 330° C. The degree of conversion when the polymerization system was transformed into a powder was 95%. After a further 2 hours of reaction, there were obtained 1,130 g of fine powder, corresponding to a yield of 94%. Ninety-one percent of the fine powder was found to have a particle diameter of 0.1 mm or less. On differential thermal analysis, the powder showed a heat absorption at 342° C. The loss on heating in the air at 370° C. for one hour was 0.65% by weight. The number average molecular weight was 11,000.

Workup

  1. customIn a glass flask, were placed under a nitrogen
  2. temperaturethe temperature was raised
  3. customwhile removing acetic acid
  4. distillationby distillation
  5. customreached 230° C.

Sources & evidence

ORD record
ord-d1dec88256bd4938928be3946dd090bb
Source dataset
uspto-grants-1982_02
Patent number
US04313870

Reaction notes

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