Process for ascorbic acids using alkaline earth silicate catalysts

摘要

Disclosed is a process for the preparation of ascorbic acids from 2-keto-hexonic acids or 2-keto-hexonic acid derivatives using alkaline earth silicate catalysts. The process may be carried out in water, alcohols, or in a variety of polar or moderately polar solvents or solvent mixtures and provides for simple workup and purification of ascorbic acid products. The process generates no by-product salts and thus, does not require the steps of neutralization or the handling of salt by-products. The process is particularly suited for the continuous preparation of L-ascorbic acid from 2-keto-L-gulonic acid and its esters.