Silicone compounds are divided into two categories, one is a low molecular compound of silicone, namely a silane monomer and its derivatives; the second is a silicone polymer compound, including a siloxane intermediate and a polysiloxane product ( Such as silicone oil, silicone rubber and silicone resin, etc.). They are introduced separately below.

1.1 Current silicone monomers
In 1863, C. Friedel and J. M. Crafts first produced an organosilicon compound (monomer) containing Si-C bonds. In 1872, A. Ladenburg was reacted with HgPh2 and SiCl4 to prepare organochlorosilane (PhSiCl3). In 1904, F.S.Kipping synthesized RnSiCl4-n using the Grignard method. In 1941, EGRochow invented the direct synthesis of RnHmSiCl4-(n+m) technology. Because of the easy availability of raw materials, simple process, no solvent, high space-time yield, and easy to realize large-scale production, it has been available. It quickly replaced the Grignard method. It is still the only method for synthesizing methylchlorosilane at home and abroad, and it also plays an important role in the synthesis of ethyl and phenylchlorosilane. Today, MenHmSiCl4-(n+m) accounts for about 90% of all silicone monomers, of which Me2SiCl2 is the largest, and the latter accounts for about 85% of all MenHmSiCl4-(n+m). This is mainly due to the fact that in the production of polysiloxanes at home and abroad, the main products are silicone rubber and silicone oil, and they must be made of high-purity Me2SiCl2. Therefore, we must strive to improve the selectivity of Me2SiCl2 in the direct synthesis of methylchlorosilane. Of course, how to obtain methyl chlorosilane more, faster, better and better, that is, how to increase the monomer production capacity, contact yield or space-time yield, reduce the consumption quota of raw materials and public works, and finally reduce the production cost. purpose.

At present, the direct fluidized bed synthesis of MenHmSiCl4-(n+m) is carried out at home and abroad. However, compared with the advanced level of foreign countries, our gap is objective and some places are obvious. It is known that there are many factors affecting the production level of direct fluidized bed synthesis of MenHmSiCl4-(n+m). The main points are as follows:
(1) Composition of silica powder and its particle size distribution
We must use the first grade chemical silicon as the raw material, under the protection of dry oxygen-enriched nitrogen, through the rough breaking and grinding process, and then through the sieve to obtain the silicon powder with a certain particle size distribution. After that, whether or not to dry again depends mainly on the water content of the silicon powder.
(2) MeCl
From domestic experience, it is possible to use MeCl prepared by gas-liquid phase method from MeOH and HCl, or MeCl by-produced by glyphosate. However, it is necessary to ensure a purity of >99.9%, and impurities such as H2O, MeOH, Me2O, HCl, EtCl and organophosphorus compounds contained in MeCl are <40 ppm, preferably <20 ppm.
(3) Copper catalyst and cocatalyst
It is preferable to use a high-fine three-Cu powder (Cu-Cu2O-CuO) catalyst (such as Chenguang Institute and SCM Company of the United States). In addition to the Cu catalyst, a small amount of cocatalyst is added. It is reported that the multi-cofactor provided by Chenguang Institute in China is effective. US SCM can also provide a multi-system cocatalyst. It is known that Zn, Al, Sb, Sn, P, Mn, and the like are all effective.
(4) Reaction temperature
The reaction temperature of the direct fluidized bed synthesis of MenHmSiCl4-(n+m) is preferably 270-320 °C. When the reaction is started, the lower limit is preferred, and the reaction can be carried out at ≥300 ° C in the later stage of the reaction.
(5) Reaction pressure
The system pressure of the direct fluidized bed synthesis of MenHmSiCl4-(n+m) is preferably 0.3-0.5 MPa.
(6) MeCl line speed
The linear velocity of the MeCl empty column of the direct fluidized bed synthesis of MenHmSiCl4-(n+m) is preferably 0.2~0.4m/s.
(7) Type and structure of fluidized bed
The hammer type or the upper enlarged type below the bed type is good, and the height to diameter ratio (H/ф) is preferably 6~12. The internal heat dissipation structure of the fluidized bed is critical, and it is necessary to ensure the rapid loss of the reaction heat, especially to ensure the touch. The free flow above and below the body maintains good mass transfer heat transfer effect. The bed temperature of the heat transfer oil is preferably slightly lower than (~5 °C) reaction temperature, and the reaction temperature at each point of the dense phase zone should be <±5 °C.
(8) Filtration and dust removal of reaction products
Mainly adopting external cyclone dust removal method, it can also be used with internal cyclone dust removal device, but domestic use is not very successful, and should be further tested until it passes. Really not, you can temporarily use the external two-rotation to replace the effect of internal rotation.
(9) MeCl distribution plate structure
Multi-tube structure can be used, paying great attention to the degree of opening and line speed to ensure good contact and flow of MeCl and Si-Cu contacts.
(10) Consumption quota of main raw materials (t crude methylchlorosilane monomer)
Si powder ≤ 0.25t, MeCl ≤ 0.86t, Cu powder ≤ 0.005t.
(11) Contact yield (production capacity)
~ 150g crude monomer / kg silicon-copper contact, X h (to pass), ~ 200g / kg · h (better); ~ 250g / Kg · h (very good).