The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 05, 1979
Filed:
Jan. 06, 1978
Joern Rueter, Marl, DE;
Klaus Burzin, Marl, DE;
Karl-Heinz Magosch, Marl, DE;
Roland Feinauer, Marl, DE;
Chemische Werke Huels Aktiengesellschaft, Marl, DE;
Abstract
Cyclic esters of dodecanedioic acid with aliphatic diols of 2-12 carbon atoms in the chain and substituted by up to two alkyl of 1-4 carbon atoms, are produced by thermolysis of corresponding linear polyesters under reduced pressure in the presence of catalysts by subjecting the linear polyesters to thermolysis at temperatures between 200.degree. and 300.degree. C., and by utilizing as catalyst a tin(II) salt of an aliphatic monocarboxylic acid of up to 18 carbon atoms, of an aromatic or araliphatic monocarboxylic acid of up to 36 carbon atoms, of an aliphatic or aromatic hydroxy-, poly-, ketocarboxylic acid or of a dicarboxylic acid of up to 18 carbon atoms; or a mixture of an organotin compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 are alkyl of 1-18 carbon atoms, or aryl or aralkyl of 6-36 carbon atoms, and an O,O-dialkyl-(3,5-di-tert.-butyl-4-hydroxybenzyl)-phosphonate wherein each alkyl is of 2-18 carbon atoms.