Dichlor(methyl)silan

Excerpt from ERG Guide 139 [Substances - Water-Reactive (Emitting Flammable and Toxic Gases)]:

Use AFFF, powder, carbon dioxide. NO hydrous agents. NO water. In case of fire: keep drums, etc., cool by spraying with water. NO direct contact with water.

Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Give nothing to drink. Refer for medical attention .

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

Get medical attention following all exposures to this compound.

General First Aid:

The vapor is heavier than air and may travel along the ground; distant ignition possible.

Difficult to extinguish; reignition may occur. Contact with water applied to adjacent fires will generate irritating hydrogen chloride.

· Wear positive pressure self-contained breathing apparatus (SCBA).

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

Fireproof /storage/. Separated from oxidants, food and feedstuffs, incompatible materials. ...Cool. Dry. Well closed. Keep under inert gas.

Store in a cool, dry, well-ventilated location. Separate from acids, alkalies, oxidizing materials, & water. Outside or detached storage is preferred.

Evacuate danger area! Consult an expert! Collect leaking liquid in sealable dry containers; do not use plastic containers. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer. NEVER direct water jet on liquid. (Extra personal protection: complete protective clothing including self-contained breathing apparatus.)

Eliminate all ignition sources. Stop or control the leak, if this can be done without undue risk. Use water spray to cool & disperse vapors & protect personnel. Control runoff & isolate discharged material for proper disposal.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

TERRESTRIAL FATE: All silicon chlorides are immediately and completely hydrolyzed by water(1); therefore, methyldichlorosilane is expected to instantaneously hydrolyze to methyl dihydroxysilane upon contact with moist soil. Absorption to moist soil surfaces is not expected to be an important environmental fate process(SRC) due to this rapid hydrolysis(1). Methyldichlorosilane is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 429 mm Hg(2).

AQUATIC FATE: All silicon chlorides are immediately and completely hydrolyzed by water(1); therefore, methyldichlorosilane is expected to immediately hydrolyze to methyl dihydroxysilane upon contact with water(1). Due to the rapid hydrolysis, bioconcentration and biodegradation are not important environmental factors for methyldichlorosilane(SRC) .

AQUATIC FATE: In water, chlorosilanes are hydrolyzed rapidly, releasing hydrochloric acid. /Chlorosilane/

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methyldichlorosilane, which has a vapor pressure of 429 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methyldichlorosilane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 107 days (SRC), calculated from its rate constant of 1.5X10-13 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Methyl silanes are transparent to UV radiation >290 nm(4) and therefore methyldichlorosilane is not expected to undergo direct photolytic degradation(SRC).

For more Environmental Fate (Complete) data for METHYLDICHLOROSILANE (6 total), please visit the HSDB record page.

Burning sensation. Cough. Sore throat. Laboured breathing. Shortness of breath. Symptoms may be delayed.

Redness. Blisters. Pain. Skin burns.

Redness. Pain. Severe deep burns.

Burning sensation. Abdominal pain. Shock or collapse.

All silicon chlorides are immediately and completely hydrolyzed by water therefore methyldichlorosilane is expected to immediately hydrolyze to methyl dihydroxysilane upon contact with water(1). Soil adsorption and mobility are negligible when compared to the immediate hydrolysis(SRC).

The Henry's Law constant for methyldichlorosilane is estimated as 1.3X10-2 atm-cu m/mole(SRC) using a fragment constant estimation method(1). Methyldichlorosilane's Henry's Law constant indicates that volatilization from moist soil surfaces may occur however hydrolysis from water(2) is expected to occur at a more rapid rate than volatilization from moist surfaces(SRC). All silicon chlorides are immediately and completely hydrolyzed by water therefore methyldichlorosilane is expected to immediately hydrolyze to methyl dihydroxysilane upon contact with water(2). Methyldichlorosilane is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 429 mm Hg(3).

The high volatility of /chlorosilanes/ suggests that they will move freely into the atmosphere. /Chlorosilanes/

/LABORATORY ANIMALS: Acute Exposure/ Tests by application of a drop to rabbit eyes have been made on tetrachlorosilane, dichloridimethyl silane, dichlorodiethylsilane, methyltrichlorosilane, & ethyl trichlorosilane. All the chlorosilanes were found to cause severe damage of the cornea & lids. More severe damage was caused by the alkylchlorosilanes than by tetrachlorosilane (silicone tetrachloride). The principal danger is from splash contamination. /Chlorosilanes/

/LABORATORY ANIMALS: Acute Exposure/ Corrosive to skin /of animals/ due to liberation of hydrochloric acid.

/LABORATORY ANIMALS: Acute Exposure/ All these compounds, even in very low doses ... caused severe burns of cornea and eyelids. ... /After/ application to the skin of the rabbit the region attacked by chlorosilanes blanches and then blisters appear ... /Chlorosilanes/

The rate constant for the vapor-phase reaction of methyldichlorosilane with photochemically-produced hydroxyl radicals has been estimated as 1.5X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 107 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). All silicon chlorides are immediately and completely hydrolyzed by water therefore methyldichlorosilane is expected to immediately hydrolyze to methyl dihydroxysilane upon contact with water(2). Methyl silanes are transparent to UV radiation >290 nm(3) and therefore methyldichlorosilane is not expected to undergo direct photolytic degradation(SRC).

Methyldichlorosilane

A Commercial Grade

A Placarded Amount

Chemical or material that can be mixed with readily available materials.