2-Hydroxy-4-methyl-thio-butyric acid recovery in high concn. and purity

摘要

Recovery of 2-hydroxy-4-methylthiobutyric acid (MHA) from a reaction mixt. obtd. by addn. of HCN to methylmercaptopropionaldehyde (MMP) and hydrolysis of the resultant methylmercaptopropionaldehyde cyanohydrin (MMP-CH) with H2SO4 is new. This involves liq./liq. extn. with a water-immiscible solvent and recovery of MHA by evaporating the extn. soln. to dryness. The novelty is that evapn. to dryness is carried out in such a way that the remaining extract contains < 4 wt.% water. Also claimed is MHA prepd. as above.