Nitrogen-phosphorus compound and application thereof in preparation of high/ultra-high molecular weight polyisobutene

The invention relates to a nitrogen-phosphorus compound and application thereof to preparation of high/ultra-high molecular weight polyisobutene, belongs to the field of preparation of high-molecular compounds, and provides the nitrogen-phosphorus compound which has a structural general formula (I) shown in the specification, and groups represented by R1-R5 are described in the claims and the specification. The method is used for preparing high/ultra-high molecular weight polyisobutene, and comprises the following steps: under the catalysis of a three-component composite catalyst, carrying out slurry polymerization reaction on an isobutene solution at-90 DEG C to-30 DEG C to obtain the high/ultra-high molecular weight polyisobutene, the three-component composite catalyst comprises a main initiator, a co-initiator and the nitrogen-phosphorus compound. By adding the nitrogen-phosphorus compound, the weight-average molecular weight of the obtained polyisobutene can be as high as 95000000 g/mol, and the molecular