75-78-5 Usage
Description
Dichlorodimethylsilane is a tetrahedral, organosilicon compound with the molecular formula Si(CH3)2Cl2. The compound is a colorless liquid at room temperature, has a pungent odor and readily reacts with water to form both cyclic and linear Si-O chains. On an industrial scale, dichlorodimethylsilane is manufactured as the main precursor to polysilane and dimethylsilicone compounds.
History
James Crafts and Charles Friedel are American chemists who first reported organosilicon compounds in 1863 by synthesizing tetraethylsilane from silicon tetrachloride and diethylzinc. Nevertheless, major progress in organosilicon chemistry occurred when Fredrick Kipping and his students reacted tetrachloride with Grignard reagents to produce diorganodichlorosilanes (R2SiCl2), which they used for their experiments. The dpemand for silicones increased in the 1930s as many aircraft companies needed better insulators for sealing materials and electric motors for aircraft engines; therefore, there was need for efficient synthesis of dichlorodimethylsilane.
Preparation
Dichlorodimethylsilane is prepared by passing methyl chloride through a heated tube packed with copper (I) chloride and ground silicon using Cu2O as the catalyst. Methyl chloride is the passed through a reactor to produce dichlorodimethylsilane.
2 CH3Cl + Si → (CH3)2SiCl2
The other products in this reaction apart from dichlorodimethylsilane include CH3)3SiCl, CH3SiHCl2, and CH3SiCl3, which can be separated fromone another by fractional distillation.
Applications
Dichlorodimethylsilane is majorly used in the production of silicones. Moreover, it is utilized in the synthesis of polysilanes, which are the main precursors to silicon carbide. Dichlorodimethylsilane can be used to coat glass to prevent the adsorption of micro-particles.
Physical properties
mp ?76°C; bp 70–71°C; d 1.064 g cm?3.
Uses
Different sources of media describe the Uses of 75-78-5 differently. You can refer to the following data:
1. Dichlorodimethylsilane is used to prepare a resin bound siloxane with tertiary alcohols and it is also used as a reagent for synthesis of optically active ansa-mettallocene polymerization catalysts. It acts as a precursor to silicone and polysilane compounds. It is also used in the glass coating to protect it from micro particles. It is involved in the preparation of resin bound siloxane with reactivity towards tertiary alcohols.
2. Dichlorodimethylsilane can be used as additive for pinacol cyclization; protecting group for diols and
carbonyl compounds;precursor for a wide variety of siliconbased
reagents.Dichlorodimethylsilane (1) allows clean
pinacol cyclization of a keto aldehyde to occur without competition
from an aldol reaction (eq 1).
3. Dichlorodimethylsilicon is a organosilicon compound and is the precursor to dimethylsilicone and polysilane compounds.
Production Methods
Produced by the action of silicon on methyl chloride in
presence of copper catalyst, or by Grignard reaction from
methyl chloride and silicon tetrachloride.
General Description
A colorless fuming liquid with a pungent odor. Flash point 16°F. Vapor and liquid may cause burns. Denser than water. Vapors heavier than air.
Reactivity Profile
Chlorosilanes, such as Dichlorodimethylsilane, are compounds in which silicon is bonded to from one to four chlorine atoms with other bonds to hydrogen and/or alkyl groups. Chlorosilanes react with water, moist air, or steam to produce heat and toxic, corrosive fumes of hydrogen chloride. They may also produce flammable gaseous H2. They can serve as chlorination agents. Chlorosilanes react vigorously with both organic and inorganic acids and with bases to generate toxic or flammable gases.
Health Hazard
Inhalation irritates mucous membranes. Severe gastrointestinal damage may occur. Vapors cause severe eye and lung injury. Upon short contact, second and third degree burns may occur.
Fire Hazard
Vapor may explode if ignited in an enclosed area. Reacts vigorously with water to generate hydrogen chloride. Hydrogen chloride and phosgene gases may be formed upon heating or in fire. Runoff to sewer may create fire or explosion hazard.
Safety Profile
Poison by ingestion and
intraperitoneal routes. Moderately toxic by
inhalation. A skin and severe eye irritant.
Violent reaction on contact with water.
When heated to decomposition it emits
toxic fumes of Cl-. See also
CHLOROSILANES.
Purification Methods
Other impurities are chlorinated silanes and methylsilanes. Fractionate it through a 3/8in diameter 7ft Stedman column (p 11) rated at 100 theoretical plates at almost total reflux. See purification of MeSiCl2. Solutions in heptane, 1,1,1-trichloroethane or 1-chloronaphthalene are used for the silanization of glassware and pipettes. [Sauer & Hadsell J Am Chem Soc 70 3590 1948, Beilstein 4 IV 4110.]
Check Digit Verification of cas no
The CAS Registry Mumber 75-78-5 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 7 and 5 respectively; the second part has 2 digits, 7 and 8 respectively.
Calculate Digit Verification of CAS Registry Number 75-78:
(4*7)+(3*5)+(2*7)+(1*8)=65
65 % 10 = 5
So 75-78-5 is a valid CAS Registry Number.
InChI:InChI=1/C2H6Cl2Si/c1-5(2,3)4/h1-2H3
75-78-5Relevant articles and documents
PROCESS FOR THE STEPWISE SYNTHESIS OF SILAHYDROCARBONS
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Page/Page column 54; 58, (2021/12/08)
The invention relates to a process for the stepwise synthesis of silahydrocarbons bearing up to four different organyl substituents at the silicon atom, wherein the process includes at least one step a) of producing a bifunctional hydridochlorosilane by a redistribution reaction, selective chlorination of hydridosilanes with an ether/HCI reagent, or by selective chlorination of hydridosilanes with SiCI4, at least one step b) of submitting a bifunctional hydridochloromonosilane to a hydrosilylation reaction, at least one step c) of hydrogenation of a chloromonosilane, and a step d) in which a silahydrocarbon compound is obtained in a hydrosilylation reaction.
Method for preparing methylchlorosilanes
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Paragraph 0040-0056, (2020/10/29)
The present invention relates to a method for producing methylchlorosilane by a direct synthesis method and, more specifically, to a method for preparing dimethyldichlorosilane with an improved output of methylchlorosilane (M2) and trimethylchlorosilane (M3). According to the present invention, the method for preparing methylchlorosilane comprises the step of reacting a contact composition including metal silicon, aluminum, a catalyst and a cocatalyst with methyl chloride, wherein the contact composition includes 0.1 to 0.2 parts by weight based on 100 parts by weight of metal silicon.(AA) MCS+ECM+Unreacted MC(BB) ECM+Unreacted MC(CC) FBR(MCS Reactor)(DD) ECM(By-product)(EE) Unreacted MCCOPYRIGHT KIPO 2021
Synthesis of Functional Monosilanes by Disilane Cleavage with Phosphonium Chlorides
Santowski, Tobias,Sturm, Alexander G.,Lewis, Kenrick M.,Felder, Thorsten,Holthausen, Max C.,Auner, Norbert
supporting information, p. 3809 - 3815 (2019/02/13)
The Müller–Rochow direct process (DP) for the large-scale production of methylchlorosilanes MenSiCl4?n (n=1–3) generates a disilane residue (MenSi2Cl6?n, n=1–6, DPR) in thousands of tons annually. This report is on methylchlorodisilane cleavage reactions with use of phosphonium chlorides as the cleavage catalysts and reaction partners to preferably obtain bifunctional monosilanes MexSiHyClz (x=2, y=z=1; x,y=1, z=2; x=z=1, y=2). Product formation is controlled by the reaction temperature, the amount of phosphonium chloride employed, the choice of substituents at the phosphorus atom, and optionally by the presence of hydrogen chloride, dissolved in ethers, in the reaction mixture. Replacement of chloro by hydrido substituents at the disilane backbone strongly increases the overall efficiency of disilane cleavage, which allows nearly quantitative silane monomer formation under comparably moderate conditions. This efficient workup of the DPR thus not only increases the economic value of the DP, but also minimizes environmental pollution.
