método para a produção de ésteres cíclicos

resumo método para a produção de ésteres cíclicos a presente invenção se refere a um método para a produção de ésteres de ácido carboxílico cíclicos, em particular, lactonas intramoleculares, como, por exemplo, dilactídeo, sendo que a produção desses ésteres cíclicos de ácidos carboxílicos oligoméricos é realizada por despolimerização ciclizante. durante essa reação, um produto de condensação desses ácidos carboxílicos oligoméricos é produzido como subproduto, isto é, uma mistura de ácidos carboxílicos oligoméricos de maior peso molecular que são hidrolisados em uma etapa adicional e são, desse modo, recuperados. esse hidrolisado pode é adicionado novamente à despolimerização ciclizante que é implementada na primeira etapa. 1/1 Producing cyclic ester (I) comprises (i) converting a mixture of oligomeric carboxylic acid (II) by cyclized depolymerization into (I), separating the resulting cyclic diester, and converting a part of (II), which is not converted into (I), to a residue during the cyclized depolymerization, (ii) hydrolyzing the residue, which is obtained in the step (i) to a mixture of II, an alpha -hydroxycarboxylic acid (III) or the mixture of mixture of II and (III), and (iii) supplying the hydrolyzate obtained in the step (ii) at least partially or completely in the step (i). Producing cyclic ester of formula (I) comprises (i) converting a mixture of oligomeric carboxylic acid of formula (II) by cyclized depolymerization into (I), and separating the resulting cyclic diester, and converting a part of (II), which is not converted into (I), to a residue during the cyclized depolymerization, (ii) hydrolyzing the residue, which is obtained in the step (i) to a mixture of II with higher average value of a carboxylate group of formula (Ia) of 1-20, an alpha -hydroxycarboxylic acid (III) or a mixture of mixture of II with higher average value of (Ia) of 1-20 and (III), and (iii) supplying the hydrolyzate obtained in the step (ii) at least partially or completely in the step (i). The residue comprises a mixture of (II) with higher average value of (Ia) than the mixture of (II) fed in the step (i). The cyclized depolymerization of the step (i) is continued until a maximum of 98 wt.% used mixture of (II) is converted to (I) by cyclized depolymerization. R : optionally branched 1-6C aliphatic group; and n : 2-40. [Image].