Water → 5-Amino-2-chlorobenzoic acid 1-allyloxycarbonyl-1-methyl-ethyl ester

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Reaction Steps

5.9 kg of 5% Pt/C catalyst 5% (H2O content: 62.8%) are placed in a 60-liter steel vessel together with 12 liters of water, and 470 g of 50% H3PO2 solution (≡5% phosphorus based on the catalyst) are added. The catalyst slurry is stirred for 10 minutes at room temperature, then 360 g of vanadylacetylacetonate VO(acac)2 as is (0.2 mol %) are added and the mixture is stirred for a further 5 minutes. 550 kg of a solution of 2-(chloro-5-nitro-benzoyl-oxy)-2-methyl-propionic acid allyl ester (content: 40%, 0.67 kmol) in toluene are placed in an autoclave having a stirrer and the catalyst suspension is added, rinsing the steel vessel with 15 kg of water. Hydrogenation is then carried out for 2 hours at a temperature of 100° C. and a hydrogen pressure of 5 bar. After cooling and rendering the autoclave inert using nitrogen, the catalyst is filtered off at 50° C. and washed with 50 kg of toluene. After working up by distillation, 196 kg of 2-(chloro-5-amino-benzoyloxy)-2-methyl-propionic acid allyl ester (yield 98% of theory) are obtained. The over-hydrogenated propyl ester content is <0.05%.

Provenance & Evidence