Research On Synthesis Process Of Di-sec Butyl Disulfide With Sec-butyl Chloride As The Raw Material

As an important fine chemical intermediate, di-sec butyl disulfide has a wide range of uses in pesticide, biology, materials,petroleum chemical industry, dyestuff food science and so on. In recent years, with the development of downstream products, the market demand of di-sec butyl disulfide has been increasing year by year, which causes the widespread attention both at home and abroad. Commissioned by Sanmenxia Aoke Chmical Engineering Co. Ltd, a new synthesis process of di-sec butyl disulfide was carried out in our study. With the sec-butyl chloride as the raw material, the synthesis technology, mechanism, kinetics and triphase phase transfer catalysis for the synthesis of the di-sec butyl disulfide was studied, which has the important application prospect and theoretical significance.In this experiment, we explored a new synthesis technology of di-sec butyl disulfide starting from the sec-butyl chloride, sodium sulfide and sublimed sulfur under the mild conditions and phase transfer catalysis. The product was characterized and confirmed by FTIR, GC-MS and1H NMR. Through the single-factor experiment, we got the optimal technology conditions:the amount of catalysis was4%, n(S):n(Na2S)=0.794:1,n(S):n(C4H9Cl)=0.547:1, the amount of water was6g, the reaction temperature was45℃, the recation time was10hours.Then it was further optimized by orthogonal designs, we got the optimal technology conditions:the amount of catalysis was3.5%, the amount of water was7g, n(S):n(Na2S)=0.775:1, n(S):n(C4H9C1)=0.53:1, the reaction temperature was49℃, the recation time was10.5hours.Then under the optimized conditions obtained by the orthogonal designs,the average yield was84.95%. The experiment were repeated three times with the industrial sodium sulfide as the raw material, and the average yield could reach84.3%, which is much closer to the actual industrialized production.Mechanism and Kinetics of the synthesis process were studied in this experiment. Through the experiment results, we could see that the reaction was in accordance with the single-molecule nucleophilic substitution reaction mechanism, and the reaction rate was only associated with the concentration of sec-butyl chloride. By fitting the experimental data and the the Arrhenius equation, we deduced the the apparent kinetic equation of the reaction:rA=-dCA/dt=4709867exp(-5153.99/T)CA.And through the verification, the reliability of this equation was confirmed.In order to solve the problem of catalyst recovery, we used the triphase phase transfer catalytic technology for the synthesis of di-sec butyl disulfide.With the sodium montmorillonite, chlorine and silica as the carrier, we loaded various phase transfer catalytic active center to prepare a series of triphase phase transfer catalyst. Through the characterization analysis and confirmation of FTIR, TG and XRD,the triphase phase transfer catalyst was initially applied to the study on the synthesis of di-sec butyl disulfide.To our satisfication, the catalyst could be recovered by simplefiltration and showed a good recyclability.