A kind of preparation method of diether diphthalimide

Abstract

The invention discloses a method for preparing diether bisphthalimide, comprising the step (A) making the raw material diphenol and one or more of strong base and strong base weak acid salt in a non-polar Reaction in a solvent such as toluene or o-xylene under an inert atmosphere; (B) reacting the reaction product of step (A) with phthalimide in the presence of an ionic liquid catalyst to obtain diether diphthalimide. In the invention, nucleophilic reaction is carried out in a non-polar solvent, and an ionic liquid is added as a phase transfer catalyst, thereby improving the reaction yield. After the reaction is finished, impurities are washed out by water extraction, which greatly reduces the generation of waste water. Then, the organic layer is evaporated to dryness under reduced pressure to obtain the diether diphthalimide, the process is simple, and the obtained product has high purity.

Description

technical field [0001] The invention relates to a preparation method of a diether diphthalimide, in particular to a preparation method of a bisphenol A type diether diphthalimide. Background technique [0002] Diether dianhydride is an important monomer for the synthesis of polyetherimide (PEI), and diether diphthalimide is an important intermediate for the synthesis of bisether dianhydride. The traditional method for preparing diether diphthalimide is to first prepare phenoxide in a non-polar solvent, and then synthesize diether diphthalimide by nucleophilic reaction in a polar aprotic solvent. CN1634904A, US4017511A, US4247464A etc. have all reported in aprotic polar solvents such as dimethylsulfoxide (DMSO), N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide ( In DMAC), diether diphthalimides are prepared by reacting phenoxides with phthalimide compounds substituted by benzene rings. Although such solvents can accelerate the nucleophilic substitution reaction on carbon...

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Problems solved by technology

CN1634904A, US4017511A, US4247464A etc. have all reported in aprotic polar solvents such as dimethylsulfoxide (DMSO), N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide ( In DMAC), diether diphthalimides are prepared by reacting phenoxides with phthalimide compounds substituted by benzene rings. Although such solvents can accelerate the nucleophilic substitution reaction on carbon atoms, they have high boiling points and poor thermal stability. , volatile, and miscible with water and organic phases, making it difficult to separate the product

In addition, the first step of preparing phenate usually selects non-polar solvents (such as o-xylene, toluene, etc.) to take away the water generated, and the non-polar solvent needs to be evaporated to dryness before adding the polar solvent for nucleophilic reaction. Solvent residues will affect the yield of subsequent nucleophilic reactions

In fact, evaporation of non-polar solvents is a very difficult process. During the evaporation process, phenoxides are prone to agglomeration, wall hanging, uneven heating, and solvent residues, which require high stirring.

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