VERFAHREN ZUR HERSTELLUNG VON MAKROCYCLISCHEN ESTERN

Preparation of macrocyclic esters comprises cyclising a dicarboxylic acid bis(glycol) ester by heating (a) the bis(glycol) ester, (b) a similar ester, (c) an alkylene glycol, (d) an inert, high-boiling reaction medium and (e) a catalyst, to 150-350 degrees C/0.1-500 mbar such that glycol is split-off and the macrocyclic ester is distilled-off and separated from glycol (c) by condensation. Preparation of macrocyclic esters of formula (I) comprises cyclising a dicarboxylic acid bis(glycol) ester of formula (II) by heating a mixture comprising (a) the bis(glycol) ester (II), (b) optionally up to 100% (based on wt. of (a)) of a similar ester of formula (III) - (V), (c) an alkylene glycol of formula (VI) in an amount of 1-50 mols. per mol. of (a) + (b), (d) an inert, high-boiling reaction medium in an amount of 1-20 parts wt. per part wt. of (a) + (b) and (e) a catalyst, the reaction being in a large-surface evaporator to 150-350 degrees C at 0.1-500 mbar such that glycol is split-off, with the macrocyclic ester being distilled-off and separated from glycol (c) by condensation. HO(CH2)nOCO(CH2)mCOO(CH2)nOH (II) H(O(CH2)nOCO(CH2)mCO)xO(CH2)nOH (III) H(O(CH2)nOCO(CH2)mCO)xOH (IV) HOCO(CH2)mCO(O(CH2)nOCO(CH2)mCO)xOH (V) HO(CH2)nOH (VI) m = 6-14; n = 2-6; and x = integer above 1.