Method for preparing organochlorosilanes

A process for producing organochlorosilanes in a fluidized bed reactor, comprising:

• reacting a methyl chloride-containing reaction gas with a particulate contact mass containing silicon and a catalyst, wherein the organochlorosilanes have the formula (CH3)nHmSiCl4-n-m where n=1 to 3 and m=0 or 1, wherein
• a) the reactor is described by an index,
• K
• ⁢
• 1
• =
• φ
• ·
• V
• r
• ⁢
• e
• ⁢
• a
• ⁢
• c
• ⁢
• tor
• ,
• eff
• A
• tot
• ,
• cooled
• ·
• d
• h
• ⁢
• y
• ⁢
• d
• (
• equation
• ⁢
• 1
• )
• where
• φ=fill level of the reactor,
• Vreactor, eff=effective reactor volume [m3],
• Atot, cooled=sum of cooled surface areas in the reactor [m2],
• dhyd=hydraulic reactor diameter [m],
• wherein Vreactor, eff is 1.5 to 2400 m3 and dhyd is 0.1 to 1.5 m;
• b) the constitution of the contact mass is described by an index
• K
• ⁢
• 2
• =
• R
• S
• ⁢
• i
• ·
• B
• A
• ⁢
• K
• ·
• δ
• rel
• d
• 3
• ⁢
• 2
• ,
• (
• equation
• ⁢
• 4
• )
• where
• BAK=breadth of the particle size distribution of the contact mass [μm],
• d32=particle Sauter diameter [μm],
• RSi=purity of the silicon,
• δrel=relative catalyst distribution in the contact mass,
• wherein δrel is 0.001 to 0.6, d32 is 5 to 350 μm,
• BAK is 10 to 1000 μm and RSi is 0.75 to 0.99999;
• c) the reaction conditions for the reaction of organochlorosilanes with silicon are described by an index
• K
• ⁢
• 3
• =
• u
• L
• v
• F
• ·
• 10
• 6
• ·
• p
• diff
• g
• ·
• 1
• ρ
• F
• ,
• (
• equation
• ⁢
• 7
• )
• where
• uL=superficial gas velocity [m/s],
• vF=kinematic viscosity of the fluid [m2/s],
• ρF=fluid density [kg/m3],
• pdiff=pressure drop over the fluidized bed [kg/m*s2],
• g=acceleration due to gravity [m/s2],
• wherein pdiff is 10,000 to 200,000 kg/m*s2, uL, is 0.002 to 0.4 m/s, ρF is 1 to 5 kg/m3 and vF is 3*10−6 to 2.5*10−5 m2/s;
• and wherein K1 has a value of 1 to 30, K2 has a value of 0.0005 to 2 and K3 has a value of 0.2 to 3000, and
• maintaining the values of K1, k2, and K3 within the specified values.