| 摘要 |
Bisketals of 1,3-cyclobutanedione with monovalent and divalent alcohols are disclosed as well as processes for their production from 1,3-cyclobutanedione or from 3acetoxy-2-cyclobuten-1-one contained in the distillation residues of the diketene production. The bisketals are suitable intermediate products for the production of squaric acid, for the production and/or purification of 1,3-cyclobutanedione, or as a stable form for storage or substitute for this unstable dione. The 1,3cyclobutanedione-bisketals according to the present invention have the general formula (I) wherein either R1a , R1b , R3a and R3b are the same and each represents a linear or branched lower alkyl group, or R1a and R1b are the same and R3a and R3b are the same and form a five-membered or six-membered spiro-linked ring with the ketal-oxygen atoms and the intermediate carbon atom, respectively, with the cyclobutane ring optionally substituted by one or more lower alkyl groups.
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