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PDMS process overview化工四
B95504048 彭子軒B95504050 劉邦彥B95504052 林文翔
Solid transport to reactor in Rochow synthesis processScrew conveyor Pneumatic conveyor
Easy to control the flow rate The material need to be fluidized
Low capacity Particle range 20~5000 μm
Transport distance is short Transport distance is long
Can be cooling or heating high energy cost
Dp of our Silicon particle is 100~6000 mesh =>Dp = 0.55~33.33 μm(1 μm = 180 mesh)
Screw conveyor
The reactor for Rochow synthesis--- fluidized bed reactor
Trying to estimate the packed height and the reactor volume are both our goals.
Mass flow rate=?
Bed hight=?
PDMS synthesisTarget: linear PDMS
Origin ,functionality ,and field of application of silicone structural units
Previous step Hydrolysis:
BUT…
Cyclic D4~7
linear Dn (n=4~100,molarcular weight distribution is very wide.)
: = 1:1This is a BAD news!!!
The monomer synthesis and polymerization process
D4 and D5 are major industrial products ,which are either marketed as such or used for the production of PDMS
D4 and D5 are main products
1. Cyclization process:
2. Ring-opening polymerization process:
Flow chartRochow synthesis
Hydrolysis
Methanolysis
Cyclization
Ploymerization
PDMS
( We have another choice.)
D4 +D5DMDCS
DMDCS
The Methanolysis process is:DMDCS + CH3OH --> Dn + H(Dn)OH + CH3Cl + H2O
(CH3)2SiCl2 2CH3Cl + Si/Cu2O
Si CH3Cl
Methanolysis or HydrolysisMethanolysis:
DMDCS + CH3OH Dn + H(Dn)OH + CH3Cl + H2O
Hydrolysis:DMDCS + H2O Dn + H(Dn)OH +HCl
To transport this strong acid is so expansive.
Don’t forget that CH3Cl ,the product in Methanolysis process ,which can be the raw material of Rochow direct synthesis.
raw material Market price
chloromethane 3.5RMB/kg
methanol 2.5RMB/kg
Easy to saparate.
Raw material cost is saved at least 30%
The flow chart becomes…Rochow synthesis
Methanolysis
Cyclization
Ploymerization
PDMS
D4 +D5
DMDCS
The Methanolysis process is:DMDCS + CH3OH --> Dn + H(Dn)OH + CH3Cl + H2OThe Rochow synthsis process is :2CH3Cl + Si/Cu2O → (CH3)2SiCl2
CH3ClSi CH3O
H
Previous QuestionCyclone: centrifugal settling
Axial velocity
Wall(r=R)Axis
Big particles are settled down
Future workMethanolysis process designCyclization process analysisPolymerization process analysisPolymer transportation
References
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