Methane

  • Fire damp
  • Methyl hydride
Formula
CH4
Structure
Description
Colorless odorless, compressed gas. There is a separate entry for the refrigerated liquid.
Uses
Used in the production of methanol, main component of natural gas.

Registry Numbers and Inventories.
CAS
74-82-8
EC (EINECS/ELINCS)
200-812-7
EC Index Number
601-001-00-4
EC Class
Extremely flammable
RTECS
PA1490000
RTECS class
Other
UN (DOT)
1971
Merck
12,6019
Beilstein/Gmelin
1718732
Beilstein Reference
4-01-00-00003
Swiss Giftliste 1
G-2405
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
CH4
Formula mass
16.04
Melting point, °C
-182.5
Boiling point, °C
-161.5
Vapor pressure, mmHg
205000 (25 C)
Vapor density (air=1)
0.55
Critical temperature
-83
Critical pressure
45.39
Density
0.717 g/L (20 C)
Solubility in water
0.17 g/L (10 C)
Viscosity
0.00119 (-160 C)
Surface tension
13.7 g/s2 (-160 C)
Refractive index
1.1596 (-88 C)
Dipole moment
0.04 D
Dielectric constant
1.68 (-161 C)
Partition coefficient, pKow
1.09
Thermal expansion
0.0026 at-165 C
Heat of fusion
1.1 kJ/mol
Heat of vaporization
8.19 kJ/mol
Heat of combustion
-891 kJ/mol

Hazards and Protection.
Storage
Keep in a cool, dry, dark location in a tightly sealed container or cylinder. Keep away from incompatible materials, ignition sources and untrained individuals. Secure and label area. Protect containers/cylinders from physical damage.
A B1
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Self contained breathing apparatus for high concentrations; protective clothing if exposed to liquid.
Respirators
None required under normal use. An air-supplied respirator must be used in confined spaces. Respiratory protection must conform to OSHA rules as specified in 29 CFR 1910.134.
Small spills/leaks
ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. A
Stability
Stable under normal temperatures and pressures.
Incompatibilities
Oxygen, oxidizing agents, air. Mixtures with bromine pentafluoride, chlorine, yellow mercuric oxide, nitrogen trifluoride, liquid oxygen, and oxygen difluoride may explode.
Decomposition
Carbon dioxide, carbon monoxide and water.

Fire.
Flash Point,°C
-188
Autoignition, °C
595
Upper exp. limit, %
15
Lower exp. limit, %
5
Fire fighting
DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED. SMALL FIRES: Dry chemical or carbon dioxide. LARGE FIRES: Water spray or fog. Move containers from fire area if you can do it without risk. FIRE INVOLVING TANKS: 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 direct water at source of leak or safety devices; icing may occur. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn.
Fire potential
EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air.
Hazards
Vapors are initially heavier than air and spread along the ground. Vapors may travel to source of ignition and flash back. Containers may explode when heated. Ruptured cylinders may rocket.
Combustion products
Carbon dioxide, carbon monoxide and water.
Health
2
 
Flammability
4
 
 
Reactivity
0
 

Health.
Exposure limit(s)
TLV: 1000 ppm; simple asphyxiant (ACGIH 1993-1994).
Poison_Class
5
Exposure effects
Rapid breathing and rapid heart rate are common. In severe cases abnormally low blood pressure, apnea, and cardiac arrest develop. Various disturbances including headache, dizziness, mood disturbances, numbness of the extremities, sleepiness, mental confusion, poor judgement and coordination, and memory loss may occur. Prolonged or severe hypoxia results in unconsciousness. Prolonged asphyxia may produce CNS injury. Hemiparesis has been reported with volatile substance abuse. Cerebral edema with brainstem herniation may occur. Seizures have been reported following intentional inhalation.
   Ingestion
Unlikely route of exposure.
   Inhalation
Asphyxiant. Effects are due to lack of oxygen. Moderate concentrations may cause headaches, drowsiness, dizziness, excitation, excess salivation, vomiting, and unconciousness. Lack of oxygen can kill.
   Skin
Dermal exposure may cause frostbite injury. Severe tissue burns have been reported.
   Eyes
Decreases in night vision, visual acuity, and visual fields (tunnel vision) may occur. Frothy mucous may be seen.

First aid
 
   Ingestion
This compound is a gas. Ingestion is not a likely route for exposure.
   Inhalation
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used.
   Skin
CAUTION: Exposure of skin to compressed gases as they vent may result in freezing of the skin. Treatment for frostbite may be necessary. Remove the victim from the source of contamination. IMMEDIATELY wash affected areas gently with COLD water (and soap, if necessary) while removing and isolating all contaminated clothing. Dry carefully with clean, soft towels. If symptoms such as inflammation or irritation develop, IMMEDIATELY call a physician or go to a hospital for treatment.
   Eyes
First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

Transport.
UN number
1971
Response guide
Hazard class
2.1
USCG CHRIS Code
MTH
 
Std. Transport #
4905755
 
IMO Gas Code
B