Synthesis method of broad-spectrum and high-efficiency crude oil demulsifier

The invention relates to the field of chemical treatment agents of oil field development produced liquid and particularly relates to a synthesis method of a broad-spectrum and high-efficiency crude oil demulsifier. According to the technical scheme, the method comprises the following steps: reacting higher aliphatic acid with alcohol amine to prepare alkanolamide, then carrying out ring-opening polymerization via alkanolamide, epoxypropane and oxirane according to a certain sequence and ratio, carrying out terminal group modification on the polymerized product by using quantitative polybasic organic acid, TDI or unsaturated low molecular acid, then compounding to prepare the product. The demulsifier prepared by the method has the beneficial effects that the defects of high consumption, poor effect and high content of oil in dehydrated water of the conventional water-soluble demulsifier can be overcome, the demulsifier has high interfacial activity, high wettability and infiltrability and high flocculation performance and coalescence performance, and the demulsifier has the advantages of low consumption, high adaptability, low content of oil in produced water and excellent demulsification effect.