Transcript Polydimethylsiloxane

化工四
B95504048 彭子軒
B95504050 劉邦彥
B95504052 林文翔
Solid transport to reactor in
Rochow synthesis process
Screw 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
Bed
hight=?
Mass flow
rate=?
Trying to
estimate the
packed height
and the reactor
volume are both
our goals.
PDMS synthesis
 Target: linear PDMS
Origin ,functionality ,and
field of application of
silicone structural units
Previous step
 Hydrolysis:
Cyclic D4~7
linear Dn
(n=4~100,molarcular
weight distribution is
very wide.)
BUT…
:
This is a BAD news!!!
The monomer synthesis and
polymerization process
D4 and D5 are main
products
1. 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
Flow chart
DMDCS
Hydrolysis
Rochow
synthesis
Cyclization
DMDCS
Si
Methanolysis
D4 +D5
CH3Cl
( We have another choice.)
Ploymerization
The Methanolysis process is:
DMDCS + CH3OH --> Dn + H(Dn)OH + CH3Cl + H2O
PDMS
(CH3)2SiCl2  2CH3Cl + Si/Cu2O
Methanolysis or Hydrolysis
 Methanolysis:
DMDCS + CH3OH  Dn + H(Dn)OH + CH3Cl + H2O
 Hydrolysis:
Easy to saparate.
DMDCS + H2O  Dn + H(Dn)OH +HCl
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
To transport this strong
acid is so expansive.
Raw material cost is
saved at least 30%
The flow chart becomes…
Rochow
synthesis
Si
DMDCS
Methanolysis
CH3Cl
CH3OH
Cyclization
D4 +D5
Ploymerization
The Methanolysis process is:
DMDCS + CH3OH --> Dn + H(Dn)OH + CH3Cl + H2O
The Rochow synthsis process is :
2CH3Cl + Si/Cu2O → (CH3)2SiCl2
PDMS
Previous Question
Cyclone: centrifugal settling
Axial velocity
Big particles are
settled down
Axis
Wall(r=R)
Future work
 Methanolysis process design
 Cyclization process analysis
 Polymerization process analysis
 Polymer transportation
References