| 摘要 |
<p>Prepn. of methionine which proceeds via hydantoin, HCN from the hydantoin prepn. is recovered by washing the gas evolved with either (a) aq. NH3 and CO2, which are starting materials for the hydantoin synthesis or with (b) the reaction mixture of methionine contg. hydantoin, and the washings are passed back to the hydantoin synthesis vessel and methyl mercaptan is recovered by washing the gas evolved with methylmercaptopropionaldehyde (I) and the washings passed back to the (I) synthesis vessel. The process is more economical to carry out than prior art methods, in which evolved HCN and methylmercaptan were oxidised rather than re-used.</p> |
