| 摘要 |
<p>The invention relates to a process for the preparation of polyglycerols (containing more than 50% by weight of diglycerol), which are low in cyclic components, by reaction of chlorohydrins. In this process, alpha -monochlorohydrin and epichlorohydrin are reacted at temperatures of 20 to 120 DEG C, preferably of 50 DEG C to 100 DEG C, in a molar ratio of epichlorohydrin to alpha -monochlorohydrin of 0.8:1 to 1:2.5 in the presence of acids or acid-reacting compounds and an alkaline-reacting medium, preferably an alkaline-reacting aqueous solution, is added to the unseparated reaction mixture obtained at a temperature of 50 DEG C to 120 DEG C, preferably of 80 DEG C to 95 DEG C, corresponding to the content in the reaction mixture of organically bound chlorine. The reaction mixture is desalted after addition of water by means of one or more cation exchangers and subsequently using anion exchangers, water is removed by distillation and the diglycerol/polyglycerol mixture (containing a proportion of glycerol) is separated into diglycerol, higher polyglycerols and optionally glycerol by fractional distillation.</p> |
