133 / 390
Silicon for the Chemical and Solar Industry XIII
Kristiansand, Norway, June 13 – 16, 2016
Copper transport in the methylchlorosilane fluidized bed reactor
Cécile ROSIER
1)
, Maxime RISS
1)
, and Michel HUET
1)
1
BLUESTAR SILICONES - 55 av Frères Perret 69190 SAINT FONS – France
Abstract
In the continuous methylchlorosilane process, the fresh silicon fed to the fluidized bed
reactor has to be activated in an efficient way in order to provide high and stable
performances in term of productivity and selectivity. Fresh silicon particles are
activated both by reaction with fresh catalyst and by transfer of catalyst from already
activated particles.
A specific experimental lab procedure was developed to get information on catalyst
transport from activated to fresh silicon particles. The effect of temperature,
cocatalyst concentration and addition of aluminium on copper transport in the
methylchlorosilane reactor and reaction performances of the catalytic sites resulting
from this transport were investigated.
It was observed that the amount of copper transported from activated to unactivated
silicon was only slightly affected by experimental conditions.
Cocatalysts transfer seemed more affected by experimental conditions: High
concentration of tin on added silicon fraction seemed correlated with transfer at high
temperature; high concentration of tin and zinc were obtained when the cocatalysts –
or zinc alone – were added during the transfer step.
The reactivity of the catalytic sites obtained by transfer was significantly higher than
the reactivity of the catalytic site obtained by reaction between silicon and fresh
catalyst. Best reactivities were achieved at relatively low concentrations of
cocatalysts.
Introduction
The synthesis of methylchlorosilanes is the first step of production in the silicone
industry [1, 2]. Direct process, discovered by Eugene Rochow in 1939 [3], involves a
heterogeneous catalytic reaction between silicon and methyl chloride. Copper is the
catalyst of direct synthesis. Zinc and tin are also used as promoters, as they improve
reaction performances when present in optimal proportions. Dimethyldichlorosilane
125