公开(公告)号：EP0874811A1

公开(公告)日：1998-11-04

申请号：EP96943038.0

申请日：1996-12-05

申请人： Degussa Aktiengesellschaft

发明人： HASSEBERG, Hans-Albrecht ,  HASSELBACH, Hans-Joachim ,  HUTHMACHER, Klaus ,  HÄFNER, Volker ,  HEINZEL, Harald ,  JÄGER, Barbara

IPC分类号： C07C319 ,  C07C323

CPC分类号： C07C319/28 ,  C07C319/20 ,  C07C323/52

摘要： In known processes: the MHA is isolated from a reaction mixture obtained by addition of hydrocyanic acid (HCN) to methylmercapto-propionaldehyde (MMP) and hydrolysis of the resulting methylmercapto-propionaldehyde cyanhydrine (MMP-CH) with sulphuric acid; the reaction mixture is brought into contact in a fluid/fluid extraction system with an organic solvent which is essentially non-miscible with water to form an extraction solution containing the solvent and MHA from the reaction mixture, and the MHA is obtained as an extract from this extraction solvent by evaporation. Such processes solve the problem of sulphate waste by coupling with a sulphuric acid recovery system. For effective operation of the latter, the salt-containing waste streams must undergo evaporation. According to the invention, the salt content of the reaction mixture before fluid/fluid extraction is adjusted to a level greater than about 50 wt % and preferably greater than 55 wt % relative to the total quantity of non-organic components in the reaction mixture. This improves the energy balance of the entire process, eliminates the need to evaporate highly corrosive solutions, increases the conversion rate in the hydrolysis stage and improves the distribution coefficients in the extraction. The acid obtained can be used as animal fee additive.