Hydrochloric Acid → 3-Acetoxy-2-methylbenzoic acid

HRID 1416081Notes

Reaction equation

HRID 1416081 reaction equation
[CH2:1]([O:8][C:9]1[C:10]([CH3:18])=[C:11]([CH:15]=[CH:16][CH:17]=1)[C:12]([OH:14])=[O:13])[C:2]1C=CC=CC=1.[OH-].[Na+].[H][H].C(OC(=O)C)(=[O:25])C.Cl>O.[Pd]>[C:1]([O:8][C:9]1[C:10]([CH3:18])=[C:11]([CH:15]=[CH:16][CH:17]=1)[C:12]([OH:14])=[O:13])(=[O:25])[CH3:2]

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 7918Acetic AnhydrideHCID 14798Sodium HydroxideHCID 118068023-Benzyloxy-2-methyl-benzoic acidHCID 178418361HCID 178418361, compound2×

Product 1

HCID 37985573-Acetoxy-2-methylbenzoic acidYield 93.7%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

A solution of 3-benzyloxy-2-methylbenzoic acid (50 g, 0.21 mol) and sodium hydroxide (20 g, 0.5 mol) in 700 g of water and 2 g of 5% Pd/C catalyst (50% water-moist) is added to a 21 steel autoclave with an aerating stirrer. 10 bar of hydrogen are injected at a temperature of 25° C. and a stirring speed of 800 rpm. Consumed hydrogen is replaced by repeated injection. After 15 min, the absorption of hydrogen falls off. The catalyst is filtered off at room temperature through a pressure filter. 735.8 g of a crude solution are obtained, from which 7.1g of toluene are separated off in a separating funnel. The aqueous crude solution is cooled to 0° C. in a 1 l four-necked flask with a pH meter. The pH is 14. 31.3 g (0.3 mol) of acetic anhydride are added dropwise in the course of 5 min; the pH falls to 6.0. The solution is then slowly treated (pH 1.1) with 49.3 g (0.5 mol) of hydrochloric acid (37% strength). A white precipitate is deposited in the course of this. The suspension is stirred for a further half hour, then the precipitate is filtered off and washed twice with 50 g of ice water. After drying, 37.5 g (93.7% of theory) of 3-acetoxy-2-methylbenzoic acid are obtained (melting point: 147° C.).

Workup

  1. customare injected at a temperature of 25° C.
  2. customthe absorption of hydrogen
  3. filtrationThe catalyst is filtered off at room temperature through a pressure
  4. filtrationfilter
  5. custom735.8 g of a crude solution are obtained, from which 7.1g of toluene
  6. customare separated off in a separating funnel
  7. filtrationthe precipitate is filtered off
  8. washwashed twice with 50 g of ice water
  9. customAfter drying

Sources & evidence

ORD record
ord-85117233190d4a318af5c64b5900e2b4
Source dataset
uspto-grants-1999_06
Patent number
US05910605

Reaction notes

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