2Solid transport to reactor in Rochow synthesis process Screw conveyorPneumatic conveyorEasy to control the flow rateThe material need to be fluidizedLow capacityParticle range 20~5000 μmTransport distance is shortTransport distance is longCan be cooling or heatinghigh energy costDp of our Silicon particle is 100~6000 mesh=>Dp = 0.55~33.33 μm(1 μm = 180 mesh)Screw conveyor
3The reactor for Rochow synthesis --- fluidized bed reactor Bed hight=?Trying to estimate the packed height and the reactor volume are both our goals.Mass flow rate=?
4PDMS synthesis Target: linear PDMS Origin ,functionality ,and field of application of silicone structural units
5: = 1:1 Previous step Hydrolysis: Cyclic D4~7 linear Dn (n=4~100,molarcular weight distribution is very wide.)BUT…:= 1:1This is a BAD news!!!
6The monomer synthesis and polymerization process D4 and D5 are main products1. Cyclization process:2. Ring-opening polymerization process:D4 and D5 are major industrial products ,which are either marketed as such or used for the production of PDMS
7Flow chart Hydrolysis DMDCS Rochow synthesis Cyclization DMDCS MethanolysisD4 +D5SiCH3Cl( We have another choice.)PloymerizationThe Methanolysis process is:DMDCS + CH3OH --> Dn + H(Dn)OH + CH3Cl + H2OPDMS(CH3)2SiCl2 2CH3Cl + Si/Cu2O
8Methanolysis or Hydrolysis Methanolysis: DMDCS + CH3OH Dn + H(Dn)OH + CH3Cl + H2OHydrolysis: DMDCS + H2O Dn + H(Dn)OH +HClEasy to saparate.Don’t forget that CH3Cl ,the product in Methanolysis process ,which can be the raw material of Rochow direct synthesis.To transport this strong acid is so expansive.raw materialMarket pricechloromethane3.5RMB/kgmethanol2.5RMB/kgRaw material cost is saved at least 30%
9The flow chart becomes… DMDCSRochow synthesisMethanolysisCyclizationCH3OHD4 +D5SiCH3ClPloymerizationThe Methanolysis process is:DMDCS + CH3OH --> Dn + H(Dn)OH + CH3Cl + H2OThe Rochow synthsis process is :2CH3Cl + Si/Cu2O → (CH3)2SiCl2PDMS
10Previous Question Cyclone: centrifugal settling Axial velocity Big particles are settled downAxisWall(r=R)
11Future work Methanolysis process design Cyclization process analysis Polymerization process analysisPolymer transportation