The invention relates to a preparation method of an efficient
crude oil desalting
demulsifier. The preparation method comprises the following specific steps: (1) performing
isocyanic acid esterification modification on methoxy
polyethylene glycol; (2) preparing glycidyl dimethyl alkylammonium
chloride; (3) preparing quaternized carboxyalkyl
chitosan; (4) modifying the methoxy
polyethylene glycol and the quaternized carboxyalkyl
chitosan for reaction to obtain a target product, namely, methoxy
polyethylene glycol-grafted quaternized carboxyalkyl
chitosan. By taking chitosan type natural
macromolecular compounds as raw materials, the efficient
crude oil desalting
demulsifier has many advantages of wide availability, nature, nontoxicity,
sustainability, high
biocompatibility, degradability and the like. The prepared
demulsifier is good in demulsifying and
dehydration effect; meanwhile, molecules of the demulsifier contain a large quantity of carboxy
alkyl groups and
quaternary ammonium salt groups, so that the demulsifier is extremely high in combination capacity for negatively charged ions such as
metal cations and
naphthenic acid radicals, and particles with
electronegativity on the surfaces, and can remove oil-soluble salt during dehumidification.