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 DIMETHYLDICHLOROSILANE, 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.
Chemical Properties
Colorless to brown liquid
Physical properties
mp ?76°C; bp 70–71°C; d 1.064 g cm?3.
Uses
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).
Uses
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.
Potential Exposure
PrimaryIrritant. Used as an intermediate in the manufacture of silicone polymers.
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. If victim is conscious, administer water ormilk. Do not induce vomiting. Medical observation isrecommended for 2448 h after breathing overexposure, aspulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consideradministering a corticosteroid spray.
storage
(1) Color Code—Red: Flammability Hazard: Storein a flammable liquid storage area or approved cabinetaway from ignition sources and corrosive and reactivematerials. (2) Color Code—Blue: Health Hazard/Poison:Store in a secure poison location. Dimethyldichlorosilanemust be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates, chlorates, andnitrates), since violent reactions occur. Before entering confined space where this chemical may be present, check tomake sure that an explosive concentration does not exist.Store in tightly closed containers in a cool, well-ventilatedarea away from water, steam, or moisture, because toxicand corrosive hydrogen chloride gas can be produced. Donot store at temperatures above 50℃/122°F. Sources ofignition, such as smoking and open flames, are prohibitedwhere dimethyldichlorosilane is handled, used, or stored.Metal containers involving the transfer of 5 gallons or moreof dimethyldichlorosilane should be grounded and bonded.
Shipping
Dimethyldichlorosilane requires a shipping labelof “FLAMMABLE LIQUID, CORROSIVE.” It falls inHazard Class 3 and Packing Group II
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.]
Incompatibilities
Forms explosive gas mixture with air.Water, steam, and moisture forms toxic and corrosivehydrogen chloride gas. Incompatible with acetone, amines,ammonia, alcohols, strong oxidizers, caustics. Attacks mostmetals. Do not store in temperatures above 122°F/50℃.
