Chlorination Reaction And Control Of Cis-Polybutadiene

In generally, chlorination of unsaturated rubber such as cis-polybutadiene was always carried out with chlorine used as chlorinating agent. In this paper, a novel chlorinating agent,which is tert-butyl hypochlorite,was synthesized and characterized successfully. Then, the chlorination reaction behaviors of the title chlorinating agent with cis-1, 4-polybutadiene rubber (BR) were investigated in detail and the chlorination reaction must be carried out in the absence of organic acid. In order to introduce some active chlorine atoms, chloroacetic acid was selected as organic acid during the chlorination reaction.The synthesis reaction of t-butyl hypochlorite with sodium hypochlorite and tert-butanol in the absence of glacial acetic acid were studied in detail. The effects of reaction temperature, ratio of reagents, addition pattern on purity and yield of tert-butyl hypochlorite were investigated and the optimum technical condition has been gained. The purity and the kinds of impurity of tert-butyl hypochlorite were characterized by gas chromatogram-mass spectrum. The results showed that the content of tert-butyl hypochlorite is decrease and the content of impurity of tert-butanol is increase with storage time. The chlorination reaction behaviors of the agent with nickel-PB were also investigated. The above reaction mechanism and the structure were determined or characterized by 1H-NMR and IR. It can be confirmed that the reaction was carried out through addition reaction mechanism, the chlorine atom and the active chlorine was introduced to BR chain. Firstly, it can be concluded that the gel content of chlorinated BR was affected by the ratio of chlorination agents, dropping time of tert-butyl hypochlorite and post reaction time. The chlorination degree of BR can also be affected by the ratio of chlorination agents and the polarity of solvents. Secondly, the effect of kinds of anti-oxides on the gel content of chlorinated BR was also studied in order to decrease gel content. It can be confirmed that the controlling effect of anti-oxides was very different: the best one was hydroquinone, next was P-hydroxyanisole.In a word, a new kind of chlorinated BR with two kinds of chlorine had been synthesized, and the degreed and gel content of chlorination can be controlled.