Heterogeneous organotin catalysts

1. A process for the transesterification of two esters, which process comprises reacting the two esters in a reaction mixture comprising an effective amount of an organotin compound of the formula X1, X2, or X3:

wherein

Z is —(CH 2 ) m —;

m is a number of from 4 to 24;

and Y is an insoluble phenyl-group containing copolymer,

R 1 , R 2 , R 3 are independently selected from the group consisting of halogen, C 1 -C 18 alkyl, C 1 -C 18 alkylene, phenyl, vinyl, allyl, naphthyl and aralkyl, with the proviso that at least one of R 1 , R 2 , or R 3 is a halogen;

R 4 is C 1 -C 18 alkyl, C 1 -C 18 alkylene, phenyl, vinyl, allyl, naphthyl, or aralkyl;

R 5 and R 6 are independently selected from the group consisting of halogen, C 1 -C 18 alkyl, C 1 -C 18 alkylene, phenyl, vinyl, allyl, naphthyl, and aralkyl, with the proviso that at least one of R 5 or R 6 is a halogen

with the proviso that when m is 4 or 6, two of R 1 , R 2 , and R 3 are not chlorine.

2. A process as recited in claim 1 additionally comprising the step of separating the organotin compound from the reaction mixture by a phase separation means.

3. The process of claim 1 wherein R 1 , R 2 , R 3 , R 5 and R 6 are halogen or C 4 -C 8 alkyl, and R 4 is C 4 -C 8 alkyl.

4. The process of claim 1 wherein R 1 , R 2 , R 3 , R 5 and R 6 are chlorine, butyl or octyl, and R 4 is butyl.

5. The process of claim 1 wherein m is a number from 4 to 11.