DETAILED DESCRIPTION OF THE INVENTION According to the process of the invention, cyclic carbonates having five or six-membered rings are prepared from the reaction of 1,2- or 1,3-diols and esters of carbonic acid.
Diols useful in the process of the invention have the general formulae: ##STR1## wherein R.
sub.
1 through R.
sub.
6, which may be the same or different, are selected from linear, branched, or cyclic C.
sub.
1 -C.
sub.
30 alkyl, hydroxyalkyl, aryl, or aralkyl groups.
Any pair of R groups can also be part of a ring, for example: ##STR2## Examples of suitable diols that can be used in the process of the invention include, but are not limited to, ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, trans-1,2-cyclohexanediol, cis-1,3-cyclohexanediol, 1-hydroxy-1-hydroxymethylcyclohexane, 2-cyclopentyl-1,3-propanediol, 2,2-diphenyl-1,3-propanediol, 2,2-dibenzyl-1,3-propanediol, 2,3-butanediol, pinacol, and the like, and mixtures thereof.
Preferably, the diol is ethylene glycol or propyene glycol.
Polyhydroxy aliphatic compounds that have 3 or more hydroxyl groups may also be used, provided that at least two of the hydroxyl groups comprise a 1,2- or 1,3-diol moiety.
Examples of such polyhydroxy aliphatic compounds include, but are not limited to, pentaerythritol, glycerin, trimethylolpropane, sucrose, and the like, and mixtures thereof.
Compounds that have 4 or more hydroxyl groups, such as pentaerythritol, may be able to form 2 or more cyclic carbonate moieties in the same molecule via the process of the invention.
Diesters of carbonic acid are a second necessary reactant in the process of the invention.
The diesters have the general formula: ##STR3## wherein R.
sub.
7 and R.
sub.
8, which may be the same or different, represent alkyl, aryl, or aralkyl groups.
Examples of suitable diesters of carbonic acid that may be used include, but are not limited to, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, methyl ethyl carbonate, methyl phenyl carbonate, methyl benzyl carbonate, di-n-butyl carbonate, and the like, and mixtures thereof
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Molecular Biology 
