The New Process Research On Synthesis Of N-octyl Mercaptan By Cyclic And Clean Methods

N-octyl mereaptan is mainly used for synthetic rubber production as polymerization regulators and vulcanization modifier, pharmaceuticals, dyes, pesticides and other organic synthesis intermediates. In addition, n-octyl mereaptan is still used as metal surface enhancer, organic additives, modifiers, metal corrosion inhibitor.N-octyl mercaptan was synthetized by using NaHS and n-octyl bromide which was synthesized by n-octanol, NaBr as raw materials under the phase transfer catalyst TBAB. The inorganic by-products NaBr was used to synthetize the n-octyl bromide after purification, the organic by-products octyl disulfide was reduced to the target product n-octyl mercaptan through the zinc power. The main research work is as follows:(1) N-octyl bromide was synthesized by using n-octanol, NaBr as raw materials,98%H2SO4and TBAB were as catalyst. The material ratio of NaBr to n-octanol, water,98%H2SO4and reaction temperature, reaction time, and the amount of TBAB were discussed for the reaction. The conditions were obtained through the single factor and orthogonal experiments: n(C8H17OH):n(NaBr):n(H2O):n(H2SO4)=0.8:1.0:0.85:1.15, the amount of TBAB was2%of the mass of n-octanol, the reaction temperature was130℃, the reaction time was4h, the yield was about93%, the purity was about98.5%.(2) N-octyl bromide was synthesized by using n-octanol,40%HBr as raw materials, Solid super acid SO42-/ZrO2-ZnO as the catalyst which was synthesized by ZrOCl2and Zn(NO3)2through the precipitation immersion method. The preparation conditions of solid super acid SO42-/ZrO2-ZnO were:n(ZrOCl2):n(Zn(NO3)2)=2:1, the concentration of H2SO4was0.5mol/L, the calcinations temperature was650℃, the calcinations time was4h. The solid super acid was used to prepare the n-octyl bromide, to get the conditions of the process: n(C8H17OH):n(HBr)=1:3, the reaction time was7h, the temperature was130℃, the amount of SO42-/ZrO2-ZnO was8%of the mass of n-octanol, the yield was up to 70.22%. In addition to use the IR, XRD, DSC-TG to characterize and research and determine the structure of solid super-acid SO4~2-/Zr02-ZnO, which had the solid super acid nature, and the activity of catalyst was not reduced significantly after reused six times.(3) N-octyl mercaptan was synthesized by using n-octyl bromide and70%NaHS as the raw materials under the phase transfer catalyst TBAB. The material ratio of n-octyl bromide to NaHS, the reaction temperature, the reaction time, the concentration of NaHS and the amount of TBAB were discussed for the reaction. The conditions were obtained through the single factor and orthogonal experiments: n(C8H17Br):n(NaHS)=1:1.5, the reaction temperature was60℃, the reaction time was4h, the concentration of NaHS was12.5mol/L, the amount of TBAB was1%of the mass of n-octyl bromide, the yield can reach71%. In addition to use the GC-MS, IR to characterize and research the structure of n-octyl mercaptan and determine it was the target product n-octyl mercaptan.(4) Etnanol was used as the solvent, the inorganic by-products NaBr was cycled to reuse by recrystallization, after two times recrystallization, the recovey rate of NaBr was about70%, the octyl disulfide was reduced to the target product n-octyl mercaptan. The material ratio of octyl disulfides to zinc power, HCl and the concentration of HCl, the reaction temperature, the reaction time were discussed for the reaction. The conditions were obtained through the single factor experiments: n(C8H17SSC8H17):n(Zn):n(HCl)=1:1.4:1.8, the concentration of HCl was36%, the temperature was50℃, the reaction time was2h, the octyl disulfide can be reduced to n-octyl mercaptan.(5) The material and economic cost accounting were counted on the n-octyl mercaptan for the whole process.1.05t n-octanol,0.3t NaBr,1.19t concentration H2SO4,0.025t TBAB,1.l NaHS,0.25t ethanol,0.063t zinc power and0.2t HC1were consumed to produce It n-octyl mercaptan. The material cost of n-octyl mercaptan was about31,489yuan after cost accounting.