| abstract |
Wax deposition inhibitors for crude oils are polymers of a monomer with structural units derived from at least one ester (1) of an aliphatic carboxylic acid with an aliphatic alcohol, wherein one of the acid and alcohol is ethylenically unsaturated and the other of the acid and alcohol has a long chain group with 14-40 carbons, and a monomer with structural units derived from a corresponding ester (3) with structural units derived from an aliphatic carboxylic acid and an aliphatic alcohol, one of the acid and alcohol being ethylenically unsaturated and the other having an aliphatic group having 1-13 carbons, so that at least 30%, preferably 50-90% of said aliphatic groups have 15-35 carbons. They are preferably prepared by transesterification. Mixtures of such polymers and / or the corresponding homopolymers or copolymers of ester (1) and / or long side chain polyalkylene amines, and optionally with monomeric polar additives, can be used as inhibitors. |