二苄基硫醚和二苄基二硫醚中硫的热迁移机理

HEAT TRANSFER MECHANISM OF SULFUR IN DIBENZYL SULFIDE AND DIBENZYL DISULFIDE

以二苄基硫醚(DBS)和二苄基二硫醚(DBDS)为有机含硫模型化合物,以二苯甲烷(DPM)亚甲基作为活性氢源,研究了反应温度对DBS中C烷—S键及DBDS中C烷—S和S—S键断裂以及硫的热迁移的影响.结果表明:200℃以下,DBS中C烷—S键未断裂;225℃以上,DBS中C烷—S键能够发生有效热断裂.而模型化合物DBDS在200℃时C烷—S和S—S键可发生有效热断裂.两种化合物热断裂反应遵循自由基型反应机理,两种模型化合物中硫的热迁移历程基本相同,主要产物是甲苯(PhMe)、二苯乙烯(DPE)、二苯乙烷(DPEA)和三苯乙烯(TPE),有机含硫化合物很少,说明温和条件下化合物DBS中C烷—S键及DBDS中的C烷—S和S—S键能有效热断裂,热断裂硫能有效以气体H2S形式迁出,少量转化为其他形态有机硫.

Dibenzyl sulfide （DBS） and dibenzyl disulfide （DBDS） were selected as the model sulfur-containing organic compounds, and diphenylmethane （DPM） methylene was em- ployed as the active hydrogen source, the effects of reaction temperature on the breaking of Cakyi--S bound in DBS and Calkyl-S and S S bonds in DBDS and on the heat transfer of sulfur were investigated. The results show that the Calkyl--S bond in DBS doesn＇t break below 200℃, whereas it can effectively break above 225℃. For the model compound DBDS, Calkyl--S and S--S bonds can effectivley break at 200℃. The reaction mechanism is considered as radical reac- tion, the heat transfer paths of sulfur in two kinds of compounds are very similar. The main heat breaking products are toluene （PhMe）, diphenylethene （DPE）, diphenylethane （DPEA） and triphenylethene （TPE）, and there are very little amount of other orgnic sulfur-containing compounds. This work indicates that the Calkyl-S bond in DBS and Calkyl-S and S--S bonds in DBDS can effectively break under relatively mild conditions, the thermally breaking sulfur can mainly move out in the form of H2S and another little amount of sulfur is transferred to other sulfurcontaining orgnic compounds.