METHOD FOR OBTAINING 5-HALOGENOLAEVULINIC ACID ALKYL ESTERS

摘要

The invention relates to a method for obtaining a 5-bromolaevulinic acid methyl ester (or a 5-chlorolaevulinic acid methyl ester) from a bromination mixture (or a chlorination mixture) containing a 5-bromolaevulinic acid meth yl ester (or a 5-chlorolaevulinic acid methyl ester) and produced by means of bromination (or chlorination) of laevulinic acid or a laevulinic acid methyl ester. The inventive method comprises the following steps: a) said brominati on mixture (or chlorination mixture) is dissolved in an organic solvent or solvent mixture; b) the solution is cooled to a low temperature, preferably to a temperature which is lower than -20 ~C, especially in the temperature rang e between -20 ~C to -40 ~C; c) the 5-bromolaevulinic acid methyl ester (or 5- chlorolaevulinic acid methyl ester) is crystallised out of the solution; and d) the crystalline 5-bromolaevulinic acid methyl ester (or 5-chlorolaevulini c acid methyl ester) is isolated by draining off the solution with the remaini ng bromination mixture (or chlorination mixture).