| 摘要 |
The present invention relates to a process for the manufacture of 2,2-disubstituted propiolactones from isoanhydrides and formaldehyde, as shown in the following equation: <IMAGE> +TR <IMAGE> wherein R and R1 individually may be a straight- or branched-chain alkyl, aryl or aralkyl group having 1 to 10 carbon atoms. The reaction is conducted at a temperature of from about 190 DEG C. to about 400 DEG C. in the presence of the metal oxide-silica gel complex which results from heating the calcined residue of a salt of a metal selected from the group consisting of Ta, Ti, Nb and Zr supported upon a silica gel in the presence of nitrogen and steam at a temperature of from about 650 DEG C. to about 1000 DEG C. which complex has additionally been treated by soaking in a mineral acid at a temperature of from about 25 DEG C. to about 100 DEG C. for from about 1 to about 4 hours.
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