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Chemical Datasheet

METHYLDICHLOROSILANE

4.3 - Dangerous when wet 8 - Corrosive 3 - Flammable liquid
Chemical Identifiers | Hazards | Response Recommendations | Physical Properties | Regulatory Information | Alternate Chemical Names

Chemical Identifiers

The Chemical Identifier fields include common identification numbers, the NFPA diamond, U.S. Department of Transportation hazard labels, and a general description of the chemical. The information in CAMEO Chemicals comes from a variety of data sources.
CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 75-54-7   (METHYLDICHLOROSILANE)
  • Dangerous When Wet
  • Corrosive
  • Flammable Liquid
NIOSH Pocket Guide International Chem Safety Card
none
NFPA 704
Diamond Hazard Value Description
3
4 2
W
Blue Health 4 Can be lethal.
Red Flammability 3 Can be ignited under almost all ambient temperature conditions.
Yellow Instability 2 Readily undergoes violent chemical changes at elevated temperatures and pressures.
White Special W Reacts violently or explosively with water.
(NFPA, 2010)
General Description
A colorless fuming liquid with a pungent odor. Flash point: -26°F; Boiling point: 41°C (106°F) . Vapors heavier than air. Vapor and liquid may cause burns. Denser than water and decomposed by water to form hydrochloric acid, a corrosive material.

Hazards

The Hazard fields include special hazard alerts, air and water reactions, fire hazards, health hazards, a reactivity profile, and details about reactive groups assignments and potentially incompatible absorbents. The information in CAMEO Chemicals comes from a variety of data sources.
Reactivity Alerts
Air & Water Reactions
Highly flammable. May enflame spontaneously in air [NFPA 1991]. Undergoes vigorous reaction with water to generate hydrogen chloride, heat and other products. The heat may be sufficient to ignite nearby combustible material. Methyldichlorosilane reacts vigorously with water to generate gaseous HCl. Based on a scenario where the chemical is spilled into an excess of water (at least 5 fold excess of water), half of the maximum theoretical yield of Hydrogen Chloride gas will be created in 0.12 minutes. Experimental details are in the following: "Development of the Table of Initial Isolation and Protective Distances for the 2008 Emergency Response Guidebook", ANL/DIS-09-2, D.F. Brown, H.M. Hartmann, W.A. Freeman, and W.D. Haney, Argonne National Laboratory, Argonne, Illinois, June 2009.
Fire Hazard
Special Hazards of Combustion Products: Toxic hydrogen chloride and phosgene gases may be formed.

Behavior in Fire: Difficult to extinguish; re-ignition may occur. Contact with water applied to adjacent fires will generate irritating hydrogen chloride gas. (USCG, 1999)
Health Hazard
Inhalation causes irritation of respiratory tract; heavy exposure can cause pulmonary edema. Contact of liquid with skin or eyes causes severe burns. Ingestion causes burns of mouth and stomach. (USCG, 1999)
Reactivity Profile
Chlorosilanes, such as METHYLDICHLOROSILANE, 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. Impact of dichlorosilane causes mixtures to burst into flame. This is the case, when the dichlorosilane and most likely related substances are mixed with oxidants such as potassium permanganate, lead oxide, copper oxide, or silver oxide, even under inert gas atmosphere [Bretherick, 1995, pg. 193]. With METHYLDICHLOROSILANE, toxic hydrogen chloride and phosgene gases may be formed when burned.
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below. More info about absorbents, including situations to watch out for...

Response Recommendations

The Response Recommendation fields include isolation and evacuation distances, as well as recommendations for firefighting, non-fire response, protective clothing, and first aid. The information in CAMEO Chemicals comes from a variety of data sources.
Isolation and Evacuation
Excerpt from ERG Guide 139 [Substances - Water-Reactive (Emitting Flammable and Toxic Gases)]:

As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1242 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)
Firefighting
Excerpt from ERG Guide 139 [Substances - Water-Reactive (Emitting Flammable and Toxic Gases)]:

DO NOT USE WATER OR FOAM. (FOAM MAY BE USED FOR CHLOROSILANES, SEE BELOW).

SMALL FIRE: Dry chemical, soda ash, lime or sand.

LARGE FIRE: DRY sand, dry chemical, soda ash or lime or withdraw from area and let fire burn. FOR CHLOROSILANES, DO NOT USE WATER; use AFFF alcohol-resistant medium-expansion foam; DO NOT USE dry chemicals, soda ash or lime on chlorosilane fires (large or small) as they may release large quantities of hydrogen gas that may explode. Move containers from fire area if you can do it without risk.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not get water inside containers. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. (ERG, 2016)
Non-Fire Response
Excerpt from ERG Guide 139 [Substances - Water-Reactive (Emitting Flammable and Toxic Gases)]:

Fully encapsulating, vapor-protective clothing should be worn for spills and leaks with no fire. ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). Do not touch or walk through spilled material. Stop leak if you can do it without risk. DO NOT GET WATER on spilled substance or inside containers. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. FOR CHLOROSILANES, use AFFF alcohol-resistant medium-expansion foam to reduce vapors.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Dike for later disposal; do not apply water unless directed to do so.

POWDER SPILL: Cover powder spill with plastic sheet or tarp to minimize spreading and keep powder dry. DO NOT CLEAN-UP OR DISPOSE OF, EXCEPT UNDER SUPERVISION OF A SPECIALIST. (ERG, 2016)
Protective Clothing
Full protective clothing; acid-vapor-type respiratory protection; rubber gloves; chemical worker's goggles; other protective equipment as necessary to protect skin and eyes. (USCG, 1999)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
Get medical attention following all exposures to this compound.

INHALATION: remove victim from exposure; if breathing has stopped, begin artificial respiration.

EYES: flush with water for 15 min.

SKIN: flush with water.

INGESTION: do NOT induce vomiting; give large amounts of water. (USCG, 1999)

Physical Properties

The Physical Property fields include properties such as vapor pressure and boiling point, as well as explosive limits and toxic exposure thresholds. The information in CAMEO Chemicals comes from a variety of data sources.
Chemical Formula:
  • CH4Cl2Si
Flash Point: -14 ° F (USCG, 1999)
Lower Explosive Limit (LEL): 6 % (USCG, 1999)
Upper Explosive Limit (UEL): 55 % (USCG, 1999)
Autoignition Temperature: greater than 600 ° F (USCG, 1999)
Melting Point: -135 ° F (USCG, 1999)
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: 1.11 at 77 ° F (USCG, 1999)
Boiling Point: 106.7 ° F at 760 mm Hg (USCG, 1999)
Molecular Weight: 115 (USCG, 1999)
Water Solubility: data unavailable
Ionization Potential: data unavailable
IDLH: data unavailable

AEGLs (Acute Exposure Guideline Levels)

Final AEGLs for Methyl dichlorosilane (75-54-7)
Exposure Period AEGL-1 AEGL-2 AEGL-3
10 minutes 0.9 ppm 50 ppm 310 ppm
30 minutes 0.9 ppm 22 ppm 110 ppm
60 minutes 0.9 ppm 11 ppm 50 ppm
4 hours 0.9 ppm 5.5 ppm 13 ppm
8 hours 0.9 ppm 5.5 ppm 13 ppm
(NAC/NRC, 2017)

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Methyl dichlorosilane; (Dichloromethylsilane) (75-54-7) 0.9 ppm 11 ppm 50 ppm LEL = 6000 ppm
(DOE, 2016)

Regulatory Information

The Regulatory Information fields include information from the U.S. Environmental Protection Agency's Title III Consolidated List of Lists, the U.S. Department of Homeland Security's Chemical Facility Anti-Terrorism Standards, and the U.S. Occupational Safety and Health Administration's Process Safety Management of Highly Hazardous Chemicals Standard List (see more about these data sources).

EPA Consolidated List of Lists

No regulatory information available.

DHS Chemical Facility Anti-Terrorism Standards (CFATS)

RELEASE THEFT SABOTAGE
Chemical of Interest CAS Number Min Conc STQ Security
Issue
Min Conc STQ Security
Issue
Min Conc STQ Security
Issue
Methyldichlorosilane 75-54-7 ACG APA sabotage/ contamination

(DHS, 2007)

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

Alternate Chemical Names

This section provides a listing of alternate names for this chemical, including trade names and synonyms.