General Description
A colorless gas with a faint sweet odor. Shipped as a liquid under its vapor pressure. A leak may either be liquid or vapor. Contact with the liquid may cause frostbite by evaporative cooling. Easily ignited. Vapors heavier than air. Can asphyxiate by the displacement of air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. Used to make other chemicals and as a herbicide.
Reactivity Profile
METHYL CHLORIDE(74-87-3) can react vigorously with oxidizing agents. May react explosively with sodium, potassium, sodium-potassium alloy, magnesium, zinc. Reacts with aluminum powder in the presence of catalytic amounts of aluminum chloride to form pyrophoric trimethylaluminum. When heated to decomposition, METHYL CHLORIDE(74-87-3) emits highly toxic fumes of chlorine [Bretherick, 5th ed., 1995, p. 176].
Air & Water Reactions
Highly flammable.
Hazard
Flammable, dangerous fire risk, explosive
limits in air 10.7–17%. Narcotic. Psychic effects.
Central nervous system impairment; liver, kidney and testicular damage, and teratogenic effects.
Questionable carcinogen.
Health Hazard
Inhalation causes nausea, vomiting, weakness, headache, emotional disturbances; high concentrations cause mental confusion, eye disturbances, muscular tremors, cyanosis, convulsions. Contact of liquid with skin may cause frostbite.
Potential Exposure
Methyl chloride is used as a methylating and chlorinating agent in organic chemistry; Used in
production of silicones and tetramethyl lead. In petroleum
refineries it is used as an extractant for greases, oils, and
resins. Methyl chloride is also used as a solvent in the synthetic rubber industry; as a refrigerant; and as a propellant
in polystyrene foam production. In the past it has been used
as a local anesthetic (freezing). It is an intermediate in drug
manufacture.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit. If
frostbite has occurred, seek medical attention immediately;
do NOT rub the affected areas or flush them with water. In
order to prevent further tissue damage, do NOT attempt to
remove frozen clothing from frostbitten areas. If frostbite
has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water. Medical observation is
recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for
pulmonary edema, a doctor or authorized paramedic may
consider administering a drug or other inhalation therapy
Shipping
UN1063 Methyl chloride, or Refrigerant gas
R 40, Hazard Class: 2.1; Labels: 2.1-Flammable gas.
Cylinders must be transported in a secure upright position,
in a well-ventilated truck. Protect cylinder and labels
from physical damage. The owner of the compressed gas
cylinder is the only entity allowed by federal law (49CFR)
to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without
the express written permission of the owner
Incompatibilities
Violent reaction with chemically active
metals, such as potassium, powdered aluminum; zinc, and
magnesium. Reaction with aluminum trichloride, ethylene.
Reacts with water (hydrolyzes) to form hydrochloric acid.
Attacks many metals in the presence of moisture
Description
Methyl chloride is a colorless, flammable gas
with a faintly sweet, nonirritating odor at room
temperature. It is shipped as a transparent liquid
under its vapor pressure of about 59 psig at
70°F (407 kPa at 21.1℃).
Methyl chloride burns feebly in air, but forms
mixtures with air that can be explosive within its
flammability range.
Dry methyl chloride is very stable at normal
temperatures and in contact with air. In the
presence of moisture, it hydrolyzes slowly,
which results in the formation of corrosive hydrochloric
acid. At temperatures above 700°F
(371℃), methyl chloride may decompose into
toxic end-products (hydrochloric acid, phosgene,
chlorine, and carbon monoxide). It is
slightly soluble in water and very soluble in
alcohol, mineral oils, chloroform, and most organic
liquids.
Chemical Properties
Methyl chloride is a colorless gas with
a faint, sweet odor which is not noticeable at dangerous
concentrations. The odor threshold is 10 ppm. Shipped
as a liquefied compressed gas.
Chemical Properties
Methyl chloride,CH3CI, is a flammable, narcotic,colorless compressed gas or liquid with a faintly sweet odor.Slightly soluble in water and soluble in alcohol this gas boils at -23.7℃ and freezes at -97.6℃ and is used as a refrigerant, catalyst carrier, and methylating agent. Also known as chloromethane.
Waste Disposal
Return refillable compressed
gas cylinders to supplier. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant
(≥100 kg/mo) must conform to EPA regulations governing
storage, transportation, treatment, and waste disposal.
Controlled incineration with adequate scrubbing and ash
disposal facilities
Physical properties
Colorless, liquefied compressed gas, with a sweet, ethereal odor. Volatile flammable gas. An
experimentally determined odor threshold concentration of >100 ppmv was reported by Leonardos
et al. (1969).
Definition
ChEBI: A one-carbon compound that is methane in which one of the hydrogens is replaced by a chloro group.
Production Methods
Methyl chloride has been used in rubber adhesives and other
rubber solutions; in the pharmaceutical industry; as a paint
and varnish remover; in solvent degreasing; in aerosol
2 JON B. REID AND CUSTODIO V. MUIANGA formulations; in food and drug processing; in the plastics
industry; in hair sprays, insecticides, and spray paints; as a
cosolvent or vapor pressure depressant; as a blowing agent
for flexible polyurethane foams; as a cleaning solvent for
printed circuit boards; as a stripper solvent for photoresists;
as a solvent for cellulose acetate fiber; in plastic film; in
protective coatings; in chemical processing; as a carrier
solvent for herbicides and insecticides; to extract heatsensitive,
naturally occurring substances such as cocoa,
edible fats, spices, and beer hops; for decaffeinating coffee;
as a refrigerant; in oil dewaxing; as a dye and perfume
intermediate; in the textile industry; as a postharvest fumigant
for strawberries; as a grain fumigant; for degreening
citrus fruits; as an industrial solvent; in low-temperature
extraction; as a solvent for oil, fats, bitumen, esters, resins,
and rubber; in coating photographic films; as a food additive;
in synthetic fibers and leather coatings; as a spotting agent;
and in organic synthesis.
Production Methods
Methyl chloride is also commercially produced by reaction of HCl on methanol in the presence of zinc chloride. Methyl chloride is mainly used in the production of silicone resins and rubbers. Silicon is reacted with an excess of methyl chloride at 300 °C in the presence of a copper catalyst. The product includes mono-, di-, and trichloromethyl silanes. Hydrolysis of the chloro groups converts them into the corresponding hydroxymethylsilanes.
Fire Hazard
Flammable gas, burns with a smoky flame;
autoignition temperature 632°C (1170°F).
Methyl chloride forms explosive mixtures
with air within the range 7.6–19.0% by
volume in air. It reacts explosively with
alkali metals, potassium, sodium, or lithium;
sodium–potassium alloy; and with magnesium, aluminum, or zinc in powder form.
Materials Uses
Dry methyl chloride may be contained in such
common metals as steel, iron, copper, and
bronze, but it has a corrosive action on zinc,
aluminum, die castings, and possibly magnesium
alloys. Methyl chloride must not be used
with aluminum, since in the presence of moisture
it forms spontaneously flammable methyl
aluminum compounds upon contact with that
metal. No reaction occurs, however, with the
drying agent, activated alumina.
Gaskets made of natural rubber and many
neoprene compositions should be avoided because
methyl chloride dissolves many organic
materials. Pressed fiber gaskets, including those
made of asbestos may be used with methyl chloride.
Polyvinyl alcohol is unaffected by methyl
chloride, and its use is also recommended. Medium-
soft metal gaskets may be used for applications
where alternating stresses such as those resulting from large temperature changes do not
lead to "ironing out" and consequent leakage.
Physiological effects
Methyl chloride is toxic, and areas where it is
handled must be adequately ventilated. It is
particularly dangerous in that it has no pronounced
odor to serve as a warning.
It acts as an anesthetic about one-fourth as
potent as chloroform, and also acts as a narcotic.
Inhalation must be avoided. Mild cases of
methyl chloride poisoning usually suffer from ataxia, lightheadedness, confusion, tremors,
nausea and vomiting, and frequently from anorexia
after a latent period of one-half to several
hours. Hiccough and constricting pain in the
neck may also be experienced. Visual disturbances
such as double vision are frequently reported.
Severe nonfatal poisonings are also characterized
by a latent period of several hours between
exposure and the onset of the first signs
or symptoms. This varies with individual susceptibility
and the intensity of exposure. Exposure
to high concentrations of several hundred
ppm or more leads successively to dizziness,
headache, vertigo, loss of coordination, nausea
and vomiting, abdominal pain, tremors, extreme
nervousness, mental confusion, convulsion,
unconsciousness, coma, and eventually death.
Rapid pulse, lowered blood pressure, elevated
body temperature, and rapid respiration are
among additional signs of exposure that may be
present. Some victims may show signs of liver
injury associated with jaundice and porphyrinuria,
and renal disturbances characterized by
albuminuria and oliguria, which may pass into
anuria. Complete recovery from severe
methyl chloride poisoning may take weeks or
months.
Fatal methyl chloride poisoning can have
symptoms similar to those of severe nonfatal
poisoning. Apparent recovery from what seems
a mild exposure through inhalation may be followed
by serious, prolonged or even fatal aftereffects
within a few days or weeks as a result of
cerebral and pulmonary edema and circulatory
failure. Repeated exposures are dangerous because
methyl chloride is eliminated slowly from
the body, where it is converted into hydrochloric
acid and methyl alcohol (wood alcohol).
ACGIH recommends a Threshold Limit
Value-Time-Weighted Average (TLV-TWA)
of 50 ppm (103 mg/m3
) for methyl chloride.
The TLV-TWA is the time-weighted average
concentration for a normal 8-hour workday and
a 40-hour workweek, to which nearly all workers
may be repeatedly exposed, day after day,
without adverse effect. ACGIH also recommends
a Threshold Limit Value-Short Term
Exposure Limit (TLV-STEL) of 100 ppm (207
mg/m3
) for methyl chloride. The TLV-STEL is
the 15-minute TWA exposure that should not be
exceeded at any time during a workday even if
the 8-hour TWA is within the TLV-TWA. Exposures
above the TLV-TWA up to the STEL
should not be longer than 15 minutes and should
not occur more than 4 times per day. There
should be at least 60 minutes between successive
exposures in this range .
OSHA lists an 8-hour Time-Weighted Average-
Permissible Exposure Limit (TWA-PEL)
of 100 ppm for methyl chloride. TWA-PEL is
the exposure limit that shall not be exceeded by
the 8-hour TWA in any 8-hour work shift of a
40-hour workweek. In addition, OSHA lists an
acceptable ceiling concentration of 200 ppm for
methyl chloride. The acceptable ceiling concentration
is the exposure limit that shall not be
exceeded at any time during an 8-hour shift.
Methyl chloride has an exception in that it has
an acceptable maximum peak above the acceptable
ceiling concentration of 300 ppm for an
8-hour shift as long as the maximum duration is
only once for 5 minutes in any hour.
Contact of methyl chloride liquid (or vapor in
a concentrated stream) with the skin or the eyes
must also be avoided, for such contact can result
in a condition resembling frostbite of the tissues.
Carcinogenicity
Methyl chloride was mutagenic to bacteria
and genotoxic in a number of mammalian cell
systems in vitro.14 It gave positive results in the
dominant lethal test in rats in vivo.
NIOSH recommends that methyl chloride
be considered a potential occupational teratogen
and carcinogen.
The IARC states that there is inadequate
evidence for the carcinogenicity of methyl
chloride to experimental animals and humans.
Source
Drinking water standard: No MCLGs or MCLs have been proposed although methyl chloride
has been listed for regulation (U.S. EPA, 1996). In addition, 100 μg/L was recommended (U.S.
EPA, 2000).
Environmental Fate
Biological. Enzymatic degradation of methyl chloride yielded formaldehyde (Vogel et al.,
1987).
Photolytic. Reported photooxidation products via OH radicals include formyl chloride, carbon
monoxide, hydrogen chloride, and phosgene (Spence et al., 1976). In the presence of water, formyl
chloride hydrolyzes to HCl and carbon monoxide, whereas phosgene hydrolyzes to hydrogen
chloride and carbon monoxide (Morrison and Boyd, 1971).
Methyl chloride reacts with OH radicals in the atmosphere at a rate of 8.5 x 10-14 cm3/sec with a
lifetime of 135 d (Cox et al., 1976).
Chemical/Physical. The estimated hydrolysis half-life at 25 °C and pH 7 is 0.93 yr (Mabey and
Mill, 1978).
The evaporation half-life of methyl chloride (1 mg/L) from water at 25 °C using a shallow-pitch
propeller stirrer at 200 rpm at an average depth of 6.5 cm was 27.6 min (Dilling, 1977).
Solubility in water
Miscible with chloroform, ether, glacial acetic acid (U.S. EPA, 1985), and other chlorinated
hydrocarbons including carbon tetrachloride.
storage
All personnel handling methyl chloride cylinders
should be fully informed about the dangers
that can arise from improper handling of methyl
chloride. The cylinder and system should be
grounded before use. Before introducing methyl
chloride into any apparatus or equipment, it
should be tested for leaks, all leaks repaired,
and the apparatus thoroughly dried. Only
nonsparking tools should be used with methyl
chloride. Chemical safety goggles and/or a
full-face shield should be used when handling
liquid methyl chloride.
Purification Methods
Bubble methyl chloride through a sintered-glass disc dipped into conc H2SO4, then wash it with water, condense it at low temperature and fractionally distil it. It has been distilled from AlCl3 at -80o. Alternatively, pass it through towers containing AlCl3, soda-lime and P2O5, then condense and fractionally distil it. Store it as a gas. [Beilstein 1 IV 28.]
GRADES AVAILABLE
Methyl chloride is available for commercial and
industrial use in various grades having much the
same component proportions from one producer
to another. Purities generally range from a
minimum of99.5 mole percent.