The invention relates to particular
orthoester based polymers as well as the use of specific
orthoester based polymers as a
demulsifier for water / oil emulsions. Products suitable for use according to the invention have the formula (I), wherein R1 is
hydrogen or a hydrocarbyl group with 1-4 carbon atoms, R2, R3, and R4 are, independently, a group comprising C3-C4 alkyleneoxy groups and / or ethyleneoxy groups in any order, and an
end group Y, which is, independently,
hydrogen, a hydrocarbyl group with 1-30 carbon atoms, a group —(CH2)zNR5R6 or —(CH2)zN+R5R6R7, wherein each of R5, R6, and R7 is, independently, an
alkyl group with 1-22 carbon atoms or —CH2CH2OH, and z is 2 or 3, provided that at least one of the groups R2, R3, and R4 comprises at least one block of at least on then average 4 alkyleneoxy groups with 3 and / or 4 carbon atoms, and provided that if Y is
hydrogen, then at least one of n and m is a number of 1-100, or a di- or polycondensate of the
polymer via free hydroxyl groups in R2, R3 or R4.