Hydrochloric Acid → 2-Methylbenzoyl chloride

HRID 2165871Notes

Reaction equation

HRID 2165871 reaction equation
Cl.[CH3:2][C:3]1[CH:11]=[CH:10][CH:9]=[CH:8][C:4]=1[C:5](O)=[O:6].S(Cl)([Cl:14])=O>>[CH3:2][C:3]1[CH:11]=[CH:10][CH:9]=[CH:8][C:4]=1[C:5]([Cl:14])=[O:6]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 83732-Methylbenzoic acidHCID 24386Thionyl Chloride

Product 1

HCID 702762-Methylbenzoyl chloride

Procedure

Part A. A 2-L, three-necked, round-bottomed flask equipped with an addition funnel, reflux condenser, and a nitrogen sweep to an HCl gas scrubber was charged with 2-methylbenzoic acid (503 g, 3.69 mol). The apparatus was cooled in an ice bath, and thionyl chloride (750 mL, 10.3 mol) was added over a period of 15 minutes. After complete addition, the ice bath was removed and the reaction mixture was warmed to about 45° in order to completely dissolve the 2-methylbenzoic acid. The reaction mixture was then allowed to gradually cool with stirring to room temperature overnight. The excess thionyl chloride and the HCl and SO2 reaction side-products were removed by vacuum distillation to afford 2-methylbenzoyl chloride as an oil, which was used without further purification. This material was transferred immediately into an addition funnel and added with mechanical stirring in 30-50 mL portions over a period of one hour to a commercial 40% dimethylamine solution (1500 mL, 13.35 mmol) which was maintained below 25° by periodic cooling with a dry ice-acetone bath. After complete addition the reaction mixture was stirred at room temperature for 1.5 hours. The reaction mixture was extracted with ether, and the combined organic extracts were washed with water, dried, and concentrated. The resulting oil was distilled under vacuum to afford N,N,2-trimethylbenzamide (409 g, 2.49 mol, 68% yield) as an oil: bp 88° (0.4 torr); IR(neat) 1650 cm-1 ; 1H NMR(CDCl3) δ 7.07-7.30 (m,4H), 3.11(s,3H), 2.81(s,3H), 2.27(s,3H). Anal. Calcd for C10H13NO: C,73.59; H,8.03; N,8.58. Found: C,73.66; H,8.18; N,8.42.

Workup

  1. temperaturereflux condenser
  2. temperatureThe apparatus was cooled in an ice bath
  3. additionAfter complete addition
  4. customthe ice bath was removed
  5. temperaturethe reaction mixture was warmed to about 45° in order
  6. dissolutionto completely dissolve the 2-methylbenzoic acid
  7. temperatureto gradually cool
  8. customThe excess thionyl chloride and the HCl and SO2 reaction side-products
  9. customwere removed by vacuum distillation

Sources & evidence

ORD record
ord-03bdc653e3c84722a131de6bd2e15fb9
Source dataset
uspto-grants-1990_07
Patent number
US04942163

Reaction notes

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