Shin-etsu Chemical Co., Ltd.

Yoshihiro Shirota

Tadashi Amano

Susumu Ueno

Yukinori Satoh

Masaaki Furuya

Hiroyuki Kobayashi

Toshio Shinohara

Mikio Aramata

Takuya Ueda

Akio Muraida

Yoshihiko Hirai

Toshiaki Maruyama

Yasuhiro Takahashi

Shigehiro Hoshida

Kinya Ogawa

Hiroshi Nakayama

Kazuhiko Kurimoto

Akihito Tsukuno

Kenichi Ito

Hideaki Ozeki

Shigeru Arai

Norinobu Wada

Naoyuki Ida

Tomomi Narita

In the synthesis of organohalosilanes by the direct process of reacting an organic halogen with metallic silicon powder, a metallic copper catalyst in the form of a thermally active metallic copper powder having large strain energy is used.

Metallic copper catalyst and process for making organohalosilanes

A diorganodichlorosilane is prepared by subjecting organochlorosilanes to disproportionation reaction in the co-presence of a SiH group-containing compound and in the presence of a primary catalyst of AlCl or AlBr and a co-catalyst of Mg, Al, Ca, Ti, Fe, Ni, Cu, Zn or Sn or a compound thereof. The invention enables disproportionation reaction of organochlorosilanes under atmospheric pressure and at a low temperature at which no substantial sublimation of AlCl or the like occurs, thus allowing the reaction equipment to be simple and improving the safety of reaction.

Preparation of diorganodichlorosilane

Organohalosilanes are prepared by reacting an organic halide with metallic silicon particles in the presence of a metallic copper catalyst which is a metallic copper powder in flake form having a bulk specific gravity of 1-3 g/cm and a mean particle size of 10 &mgr;m to 1 mm as measured by laser diffraction particle size distribution analysis.

Metallic copper catalyst and process for the synthesis of organohalosilanes

For the continuous hydrolysis of organochlorosilane, a reaction system comprising at least three stages of hydrolysis is used. Each stage includes a reactor and a phase separator wherein hydrolysis is effected to form a hydrolysis mixture which is separated into a hydrolyzate and a hydrogen chloride-containing aqueous medium. The separated aqueous medium is circulated to the reactor. The hydrolyzate is conveyed to the reactor of the subsequent stage. The organochlorosilane is fed into the first stage reactor, the aqueous medium containing an amount of water corresponding to the consumption in one stage is fed into one stage reactor from the subsequent stage, and an amount of water corresponding to the consumption in the overall reaction system is fed in the last stage. Then the entire amount of hydrogen chloride generated in multiple stages of hydrolysis is recovered as anhydrous hydrogen chloride from the first stage. The entire amount of the aqueous media separated in the phase separators is retained in the reaction system.

Continuous hydrolysis of organochlorosilanes

Methyl chloride is prepared by effecting liquid-phase reaction between hydrogen chloride and methanol in the absence of a catalyst. The reaction is effected in divided stages including at least an early stage and a last stage. The early stage of reaction is effected in a stoichiometric excess of hydrogen chloride. The last stage of reaction is effected in a stoichiometric excess of methanol. The invention is industrially advantageous in that methyl chloride can be prepared at a high conversion of hydrogen chloride while suppressing the formation of dimethyl ether by-product.

Preparation of methyl chloride

A polymerization apparatus, comprises a polymerization vessel, a reflux condenser installed outside the polymerization vessel and a pipe connected between the reflux condenser and a wall of the polymerization vessel with an end thereof opening into a gaseous phase region inside the polymerization vessel, for returning the liquid condensate to the polymerization vessel, wherein said end projects from an inner surface of the wall of the polymerization vessel into the gaseous phase region. In polymerizing a monomer having an ethylenically unsaturated double bond using the polymerization apparatus, the quantity of heat removed by the reflux condenser is increased stepwise or continuously with progress of the polymerization, such that not less than 20% of the total reaction heat generated during the whole course of the polymerization is removed by the reflux condenser. With 100 or more repeated polymerization runs, polymer scale deposition inside the vessel is minimal even below the pipe end.

Polymerization apparatus effective in preventing polymer scale deposition

A polymerization method used, particularly, in suspension polymerization of vinyl chloride, comprising a polymerization vessel (1) having a substantially cylindrical inner space, said inner space of said polymerization vessel being provided with a plurality of baffles (5) comprising vertically extending pipes, and a vertically continuously extending coil (6), and a refrigerant being passed through said baffles and said coil. High-cooling performance can be obtained, a high-speed reaction in a large-sized polymerization vessel becomes possible, and a stable polymerization reaction can be carried out. A high-quality and uniform polymer that has few fish eyes and has a high bulk specific gravity can be obtained.

Polymerization method producing vinyl chloride polymer

A polymerization process, comprises a polymerization vessel, a reflux condenser installed outside the polymerization vessel and a pipe connected between the reflux condenser and a wall of the polymerization vessel with an end thereof opening into a gaseous phase region inside the polymerization vessel, for returning the liquid condensate to the polymerization vessel, wherein said end projects from an inner surface of the wall of the polymerization vessel into the gaseous phase region. In polymerizing a monomer having an ethylenically unsaturated double bond using the polymerization apparatus, the quantity of heat removed by the reflux condenser is increased stepwise or continuously with progress of the polymerization, such that not less than 20% of the total reaction heat generated during the whole course of the polymerization is removed by the reflux condenser. With 100 or more repeated polymerization runs, polymer scale deposition inside the vessel is minimal even below the pipe end.

Vinyl chloride polymerization with recycle return projecting into gas

An improvement is proposed in the process of suspension polymerizatiopn of vinyl chloride monomer in an aqueous polymerization medium, by which a resin product of high quality relative to the contents of foamy resin and fish-eyes can be produced in a high efficiency with little deposition of polymer scale on the reactor walls. The improvment comprises heating and keeping the surfaces of the polymerization reactor and accessory equipment coming into contact with the gaseous phase above the polymerization mixture at a temperature of 55.degree. C. or higher during a period starting from a moment when the temperature of the polymerization mixture under temperature elevation up to the polymerization temperature is still 45.degree. C. or lower to a moment when conversion of the monomer into polymer is at least 10% so that foaming on the polymerization mixture can be greatly reduced.

Suspension polymerization of vinyl chloride with heating of reactor

The unreacted gaseous vinyl chloride monomer still remaining in a polymerization reactor from which the polymerizate has been removed can be discharged by blowing steam into the reactor from its top so that the gaseous monomer is pushed downward and moved out from the bottom of the reactor, followed by a conventional treatment for condensation. This method of discharge serves to put the reactor open to the ambient atmosphere without the emission of the unreacted monomer and, as such, solve the problems of the workers' health and environmental pollution.

Method of discharging gaseous vinyl chloride monomer from a

Unreacted monomer or monomers and any other volatile organic compounds contained in an aqueous dispersion of polymerizate are removed or separated by a method comprising circulating the aqueous polymerizate dispersion from the bottom of its container to the upper part of the container located over the surface of the dispersion via an exterior conduit. The pressure in the container is maintained at a level reduced to about the saturated vapor pressure of water at the temperature of the dispersion. This manner of separation of monomer from polymer serves to improve the working environment as well as the resulting polymer quality, and the monomer or monomers thus recoverd can be advantageously recycled.

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Annaka, Japan

Yoshihiro Shirota