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 conveyorEasy to control the flow rate The material need to be fluidizedLow capacity Particle range 20~5000 μmTransport distance is short Transport distance is longCan 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 pricechloromethane 3.5RMB/kgmethanol 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 CH3OH

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