Acetic Acid → Benzenepropanoic acid, 4-methoxy-beta-oxo-, ethyl ester

Participants

Reaction Steps

Simultaneous reactions were run in both a 65-L reactor and a 35-L reactor that share the same reflux system. A nitrogen atmosphere was maintained in both. 4.0 kg (100 moles) of 60% sodium hydride in mineral oil and 32 L toluene were charged into the ambient temperature reactors. The mixture was agitated for 5 minutes and allowed to settle. 20 L of the toluene solution was aspirated. 28 L of toluene was added, agitated for 5 minutes, allowed to settle and 28 L of the toluene solution was aspirated. 68 L of toluene and 8.4 L (69.7 moles) diethyl carbonate were added. The agitation was begun and the flow of Syltherm (Note 4) in reactor jackets was initiated. A solution of 5.0 kg (33.3 moles) 4-methoxyacetophenone in 12 L toluene was added over 20 minutes. When additions were complete, the jacket temperature was reduced to 10° C. and stirring continued for 16 hours. A solution of 6.7 L (117 moles) glacial acetic acid in 23 L deionized water was fed at the same rate that was previously used for the acetophenone solution. When addition was complete, agitation was stopped and the layers separated. The aqueous layer was washed once with 13 L toluene. The combined organic layers were washed twice with 6.7 L portions of 7% (w:w) aqueous sodium bicarbonate. The toluene solution was washed once with 6.7 L of 23% (w:w) aqueous sodium chloride. The organic solution was dried over 10 kg sodium sulfate, filtered, and the solvent removed on the rotary evaporator to provide the desired product.

Provenance & Evidence