Methyl iodide

  • Iodomethane
Formula CH3I
Structure
Description Colorless liquid with a sweet, pungent odor. Turns yellow, red or brown when exposed to light or moisture, lachrymator.
Uses Methylating agent, in microscopy because of its high refractive index, as imbedding material for examining diatoms, in testing for pyridine. Light sensitive etching agent for electronic circuits, component in fire extinguishers.

Registry Numbers and Inventories.
CAS 74-88-4
EC (EINECS/ELINCS) 200-819-5
EC Index Number 602-005-00-9
EC Class Carcinogenic Category 3; Harmful; Toxic; Irritant
EC Risk Phrase R 21 23/25 37/38 40
EC Safety Phrase S 36/37 38 45
RTECS PA9450000
RTECS class Tumorigen; Mutagen; Primary Irritant
UN (DOT) 2644
Merck 12,6161
Beilstein/Gmelin 969135
Beilstein Reference 4-01-00-00087
RCRA U138
EPA OPP 11
Swiss Giftliste 1 G-2511
Canada DSL/NDSL DSL
US TSCA Listed
Austrailia AICS Listed
New Zealand Listed
Japan ENCS (MITI) Listed
Korea ECL Listed

Odor Threshold Odor threshold Odorless
Properties.
Formula CH3I
Formula mass 141.94
Melting point, °C -66
Boiling point, °C 42.4
Vapor pressure, mmHg 405 (20 C)
Vapor density (air=1) 2.28
Saturation Concentration 526000 ppm at 25 C (calc.)
Evaporization number No information reported, but expected to evaporate readily.
Critical temperature 254.8
Critical pressure 72.7
Density 2.279 g/cm3 (20 C)
Solubility in water 20 g/L
Viscosity 0.606 cp at 0C
Surface tension 25.8 g/s2 at 43.5 C in contact with air
Refractive index 1.5293 (20 C)
Partition coefficient, pKow 1.51
Heat of vaporization 27.97 kj/mol
Heat of combustion -81.52 kJ/mol

Hazards and Protection.
Storage Do not store in direct sunlight. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances.
WHMIS D1A E
Handling Wash thoroughly after handling. Do not breathe dust, vapor, mist, or gas. Do not get in eyes, on skin, or on clothing. Do not ingest or inhale. Store protected from light. Use only in a chemical fume hood.
Protection Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Avoid runoff into storm sewers and ditches which lead to waterways. Provide ventilation. Do not get water inside containers.
Disposal code 9
Stability Stable under normal temperatures and pressures.
Incompatibilities Oxygen, silver chlorite, sodium, and trialkylphosphines
Decomposition Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, hydrogen iodide, iodine.

Fire.
Flash Point,°C -17
Autoignition, °C 352
Upper exp. limit, % 66
Lower exp. limit, % 8.5
Fire fighting Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Substance is noncombustible. Decomposes at high temperatures, resulting in toxic and corrosive products. Containers may explode in the heat of a fire. Vapors may be heavier than air. They can spread along the ground and collect in low or confined areas. Extinguishing media: Use extinguishing media most appropriate for the surrounding fire. Do NOT get water inside containers. For small fires, use dry chemical, carbon dioxide, or water spray. For large fires, use water spray, fog or regular foam. Cool containers with flooding quantities of water until well after fire is out.
Fire potential Iodomethane is not flammable.
Combustion products Toxic and irritating gases are generated when exposed to fire or heat.
NFPA Health 3
  Flammability 1  
  Reactivity 0  

Health.
Exposure limit(s) NIOSH REL: Ca TWA 2 ppm (10 mg/m3) [skin] See Appendix A OSHA PEL: TWA 5 ppm (28 mg/m3) [skin] IDLH Ca [100 ppm]
Carcinogin CP65
Poison_Class 1
Exposure effects Chronic inhalation may cause effects similar to those of acute inhalation.
   Ingestion Harmful if swallowed. May cause irritation of the digestive tract. May cause effects similar to those for inhalation exposure. Prolonged or repeated exposure may cause CNS effects.
   Inhalation Causes respiratory tract irritation. May cause lung damage. May cause spleen and liver damage. Initial symptoms include lethargy, drowsiness, slurred speech, ataxia, muscular incoordination, visual disturbances. May progress to convulsions, coma and death. Other symptoms include giddiness, diarrhea, sleepiness, irritability, vomiting, pallor, muscular twitching and kidney effects.
   Skin Causes skin irritation. May cause irritation with pain and stinging, especially if the skin is abraded. May cause reddening of the skin.
   Eyes Causes eye irritation. Causes redness and pain. If splashed in the eye causes conjunctivitis.

First aid		  
   Ingestion Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation Get medical aid immediately. Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration.
   Skin Get medical aid. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
   Eyes Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.

Transport.
UN number 2644
Response guide 151
Hazard class 6.1
PRTC T
Packing Group I  
USCG CHRIS Code MIO  
HS Code 2903 30 80  
Std. Transport # 4921304