| abstract |
Simultaneous prodn. of an alkylene glycol (ethylene glycol or propylene 1,2-glycol) of the formula R1-CH(OH)-CH2OH (I) and a dialkyl carbonate of the formula (R2O)2CO (II) involves reacting a cyclic carbonate (ethylene or propylene carbonate) of formula (III) with an alcohol of the formula R2OH (IV). In formulae, R1 is H or M3; R2 is 1-4C alkyl, pref. Et or esp. Me. The catalysts used are betaines (V) with quat. ammonium cation(s) and an equal number of alcoholate anion(s), contg. betaine gps. of the formula N(+)-CH2-(-CHR3)n-C(R4)(O(-)(VA)) (where R3 is H or 1-4C alkyl; R4 is H, Me or Ph; and n is 0 or 1. More specifically (V) are of formula (VB), (VC) or (VD) (where R5 is H, (substd.) alk(en)yl, a linear, branched or cyclic ether gp., opt. substd. by alkyl, aryl, alkoxy or siloxy, (substd.) 6-10C aryl or acyl; R6-9 is alkyl, aryl, aralkyl or -CH2-(-CHR3)n-C(R4R5)-OH; R10-11 are alkyl, aryl or aralkyl; or R6+R7 and/or R9+R10 is -(CH2)4-, -(CH2)5- or -C2H4-O-CH2H4-; or NR6R7R8 and/or NR9R10R11 is a (substd.) pyridine ring; A and B = a p- and q-valent monomeric, oligomeric or polymeric hydrocarbon gps. respectively; both may be substd. and/or contain Si, N, O, P and/or S hetero-atom(s) and A may also be unsatd.; and n, p and q are 1-3). USE/ADVANTAGE - (I) are valuable intermediates for polyester fibres and solvents; and (II) are valuable intermediates for polycarbonates or polyurethanes and are also useful as alkylating agents, propellant additives or solvents. Unlike the amines or cyclic ethers on which they are based, (V) and even mixts. of the amines and cyclic ethers are effective catalysts. |