| abstract |
Inhibitors of wax deposition for crude oils are polymers of a monomer with structural units derived from at least one ester (i) 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 of 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, wherein one of the acid and alcohol is ethylenically unsaturated and the other has an aliphatic group of 1-13 carbons, such that at least 30 % preferably 50-90 % of the said aliphatic groups have 15-35 carbons. They are preferably made by transesterification. Blends of such polymers and/or the corresponding homopolymers or copolymers of ester 1 and/or polyalkylene imines with long side chains, and optionally with monomeric polar additives may be used as inhibitors. |