Patent ID: 8039518

Claim:
A demulsifier for water/oil emulsions, said demulsifier comprising at least one orthoester based polymer having the general formula wherein R1 is hydrogen or a hydrocarbyl group with 1-4 carbon atoms, R2, R3, and R4 are, independently, a group comprising C 3 -C 4 alkyleneoxy groups and/or ethyleneoxy groups in any order, and an end group Y, which is, independently, hydrogen, or a hydrocarbyl group with 1-30 carbon atoms, provided that at least one of the groups R2, R3, and R4 comprises at least one block of at least on average 4 alkyleneoxy groups with 3 and/or 4 carbon atoms, and provided that if Y is hydrogen, then at least one ethyleneoxy or alkyleneoxy group is connected to Y; or a di- or polycondensate of the polymer via free hydroxyl groups in R2, R3 or R4, wherein the polymer has an average molecular weight of from 1,500 to 40,000.