Hydrochloric Acid → 3-Acetoxy-2-methylbenzoic acid

HRID 2181402Notes

Reaction equation

HRID 2181402 reaction equation
[C:1]([O:4][C:5](=[O:7])[CH3:6])(=O)[CH3:2].Cl.O[C:10]1[C:11](C)=[C:12]([CH:16]=[CH:17]C=1)[C:13]([OH:15])=[O:14]>O.[OH-].[Na+]>[C:5]([O:4][C:1]1[C:16]([CH3:17])=[C:12]([CH:11]=[CH:10][CH:2]=1)[C:13]([OH:15])=[O:14])(=[O:7])[CH3:6]

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 7918Acetic Anhydride2×HCID 2520233-Hydroxy-2-methylbenzoic Acid

Product 1

HCID 37985573-Acetoxy-2-methylbenzoic acid

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 14798Sodium HydroxideSolvent4×

Conditions

Temperature
0 °C

Procedure

In a flat-flanged vessel, 80.0 g of 3-hydroxy-2-methylbenzoic acid (purity 97.78%) are dissolved in 320.0 g of water and 120.0 g of sodium hydroxide solution (w=30%), which results in a pH of 6.9. The clear solution is cooled to 0° C. and adjusted to pH=9 by metering in sodium hydroxide solution (w=30%). Acetic anhydride and sodium hydroxide solution are now simultaneously metered in at 0-5° C. in such a way that the pH remains within the range of 8.8-9.2. 112.6 g of acetic anhydride and 172.25 g of sodium hydroxide solution (w=30%) are metered in within 2.5 h. Afterwards, the mixture is stirred for a further 1.5 h. A second flat-flanged vessel is charged with 150.0 g of water and cooled to 0° C. The reaction mixture of the first vessel and hydrochloric acid (w=37%) are simultaneously metered in at a maximum of 5° C. in such a way that a pH of 3.8-4.2 is maintained. The product precipitates out as a white precipitate. The pH is adjusted to 1 by metering in hydrochloric acid (w=37%). The product is filtered off with suction and washed with 500.0 g of water. The precipitate is dried in a vacuum drying cabinet at 60° C. for 16 h. 172.6 g of 3-acetoxy-2-methylbenzoic acid (purity 99.9%) are obtained. This corresponds to 99.28% of theory.

Workup

  1. customare now simultaneously metered in at 0-5° C. in such
  2. customare metered in within 2.5 h
  3. temperaturecooled to 0° C
  4. customare simultaneously metered in at a maximum of 5° C. in such
  5. temperatureis maintained
  6. customThe product precipitates out as a white precipitate
  7. filtrationThe product is filtered off with suction
  8. washwashed with 500.0 g of water
  9. customThe precipitate is dried in a vacuum
  10. customdrying cabinet at 60° C. for 16 h

Sources & evidence

ORD record
ord-88553acdcf7f4b8386a4cd8731c84047
Source dataset
uspto-grants-2005_05
Patent number
US06891060B2

Reaction notes

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