The invention relates to a preparation method of
cyclobutane tetracarboxylic dianhydride, and belongs to the technical field of
organic synthesis. The method comprises the steps of photochemical reaction, acidification reaction and anhydridation reaction. In the photochemical reaction,
dimethyl fumarate is refined and then added into deionized water, the photochemical reaction is carried out through a UV lamp tube, and
cyclobutane tetramethyl tetraformate is generated; the acidification reaction comprises the following steps: adding tetramethyl
cyclobutane tetraformate into a
hydrochloric acid solution, and carrying out
hydrolysis reaction to generate cyclobutane tetracarboxylic acid; the anhydride reaction comprises the following steps: adding
acetic anhydride and a PVP (
Polyvinyl Pyrrolidone)
crystallization aid into cyclobutane tetracarboxylic acid, and carrying out anhydride reaction to generate cyclobutane tetracarboxylic dianhydride; finally, through operations such as
crystallization,
filtration and pulping, the product purity is improved; the PVP
crystallization auxiliary agent is prepared from an N-vinyl pyrrolidone
monomer, 4-vinyl
benzocyclobutene, allylidene
triphenylphosphine and azodiisobutyronitrile, and the PVP crystallization auxiliary agent is prepared from the N-vinyl pyrrolidone
monomer, the 4-vinyl
benzocyclobutene, the allylidene
triphenylphosphine and the The cyclobutane tetracarboxylic dianhydride prepared by the method is high in purity and high in total yield, and can meet the requirements of industrial large-scale production.