PROCESS FOR THE PREPARATION OF LIQUID 2-HYDROXY- METHYLTHIOBUTYRIC ACID

摘要

PROCESS FOR THE PREPARATION OF LIQUID 2-HYDROXY-METHYLTHIOBUTYRIC ACID A process for the preparation of 2-hydroxy-4-methylthiobutyric acid is disclosed. 2-Hydroxy-4-methylthiobutyronitrile is hydrolyzed with mineral acid to produce an aqueous hydrolyzate containing 2-hydroxy-4-methylthiobutyric acid and substantially free of unreacted 2-hydroxy-4-methylthiobutyronitrile and 2hydroxy-4-methylthiobutyramide. 2-Hydroxy-4-methylthiobutyric acid is recovered from the hydrolyzate by extraction. Extraction may be carried out without prior separation from the hydrolyzate solution of any substantial fraction of solids present therein, and 2hydroxy-4-methylthiobutyric acid may be recovered from the extract by steam distillation. The extraction solvent has a boiling point of between about 60.degree.C and about 200.degree.C, and the distribution coefficients for 2hydroxy-4-methylthiobutyric acid between extract and raffinate, and between extract specimen and wash water, favor transfer to and retention of the acid product in the organic phase.