BUTYL RUBBER PRODUCTION PROCESS Russian patent published in 2004 - IPC

FIELD: rubber industry.

SUBSTANCE: butyl rubber is produced via isobutylene/isoprene copolymerization in diluent and/or solvent medium. Isobutylene is obtained through hydration of isobutylene contained in starting isobutylene-containing fractions obtained by pyrolysis of hydrocarbon feedstock, catalytic cracking, isobutane dehydrogenation, isomerization of linear butanes via intermediate trimethylcarbinol, which is dehydrated into isobutylene followed by isolation of trimethylcarbinol dehydration products by compression and rectification. Thus obtained isobutylene is used for blending with isoprene and return diluent and/or solvent containing unreacted isobutylene. Blend is then copolymerized with isoprene in presence of catalyst. Process also includes deactivation of catalyst, degassing of rubber, processing of return products distilled off in the course of degassing by condensation, compression, and rectification, recovery and drying of rubber. Process is characterized by that isobutylene from water-washed trimethylcarbinol dehydration products is subjected to two-step rectification: first under mild conditions of temperature 45-50^оС in bottom section of the first column and reflux-to-product ratio 3.0-4.0 and then, after mixing first-step still residue with condensate isobutylene-containing blowings obtained during isobutylene-into-trimethylcarbinol hydration process, under sever condition of temperature 90-135^оС in bottom section of the second column and reflux-to-product ratio 0.7-1.2. Isobutylene distilled of in the first rectification stage is conveyed, after azeotropic drying, to isobutylene/isoprene copolymerization zone and isobutylene distilled of in the second rectification stage is conveyed, as starting isobutylene-containing fraction, to isobutylene-into-trimethylcarbinol hydration process and/or to synthesis of 4,4-dimethyl-1,3-dioxan, optionally in combination with methyl tert-butyl ether.

EFFECT: increased productivity, increased homogeneity of rubber, and reduced specific consumption of raw materials.

3 cl, 1 dwg, 6 ex