Process method for preparing polyisobutene and polymerization device

Abstract

The invention relates to a process method for preparing polyisobutene and a polymerization device. An integrated reactor consisting of a premixer, a supergravity reactor and a tubular reactor is used as a polymerization reactor; a mixed liquid containing a monomer and diluent and a mixed liquid containing initiator and diluent are introduced to the supergravity reactor after being premixed by thepremixer according to a ratio, and cationic polymerization reaction is initiated under the condition of supergravity, and the reaction liquid enters into the tubular reactor from an outlet of the supergravity reactor to continuously finish macroscopic polymerization reaction. The average molecular weight of the polyisobutene as the obtained product is controllable and ranges from 800 daltons to 5000 daltons, the molecular weight distribution index ranges from 1.8 to 2.5, and the content of a chain end alpha-double bond can be up to over 90%. By using the supergravity polymerization process provided by the invention, the microcosmic mixing, mass transferring and heat transferring processes of a reaction is greatly enhanced; compared with the traditional stirring polymerization method, the process method ensures that the average residence time of materials in the supergravity reactor is at least shortened to over 20-30 times; and in addition, the equipment volume is greatly reduced, andthe operating cost is reduced.

Description

technical field [0001] The invention relates to a process and a polymerization device for preparing polyisobutylene by a slurry method, and also relates to the extended application of high gravity technology in polyisobutylene polymerization. Highly active polyisobutylene products with a number average molecular weight in the range of 800-5000 Daltons can be prepared by the supergravity method. technical background [0002] Polyisobutylene is an important chemical substance, which is widely used in chemical, pharmaceutical, food and other industries, and its development and utilization prospects are very broad. Polyisobutylene is usually prepared from Friedel-Crafts acid (such as AlCl 3 ) initiation, isobutene is prepared by slurry polymerization reaction in the medium of methyl chloride. Polyisobutylene is insoluble in methyl chloride and precipitates out of solution as particles, thus forming a slurry system. Polymerization is usually carried out at a temperature of abo...

AI Technical Summary

Problems solved by technology

[0005] However, due to the diversity and complexity of polymer polymerization systems, high-gravity technology is not generally applicable to the polymerization processes of different systems, and different technical solutions need to be designed according to the characteristics of different polymerization processes. Polyisobutylene polymerization systems and butyl rubber polymerization systems are both It belongs to the cationic slurry polymerization system, which requires a very high degree of microscopic mixing when the monomer initiates the polymerization

However, butyl rubber has a higher molecular weight, and the polymerization reaction is usually completed instantaneously at a lower temperature (about -100°C), and the reaction rate is faster, while the polymerization reaction of polyisobutylene needs to be carried out at a higher temperature (about -20°C). The rate is lower than that of butyl rubber, and a certain macro-mixing time must be guaranteed to complete the polymerization reaction, otherwise it is difficult to obtain high-quality products

In view of the different characteristics of the above two reaction systems, if only the known hypergravity reaction method and device are used, the residence time of the polymer material in the equipment is too short, and it is difficult to complete the polymerization process of polyisobutylene well.

In addition, studies have shown that after the polymerization raw materials enter the high-gravity rotating bed reactor, there is a phenomenon of local macro-inhomogeneity, and the initial macro-inhomogeneity will reduce to micro-mixing efficiency, which will affect the polymerization process.

Images