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Methyl bromide

Methyl bromide structure

CAS No:
74-83-9
Formula:
CH3Br
Chemical Name:
Methyl bromide
Synonyms:
Methane,bromo-;Bromomethane;Embafume;Iscobrome;Methyl bromide;Monobromomethane;Terabol;Haltox;Halon 1001;Curafume;R 40B1;1-Bromomethane;Brom-O-Gas;Methybrom;F 40B1;1361252-19-8;1519044-64-4
Categories:
Organic Chemistry > Hydrocarbons and Derivatives

Description

Methyl bromide (Bromomethane) is an odorless, sweetish, colorless gas that has been used as a soil fumigant and structural fumigant to control pests across a wide range of agricultural sectors. Methyl bromide is soluble in ethanol, benzene, carbon disulfi de, and sparingly in water. During the 1920s, methyl bromide was used as an industrial fi re extinguishing agent. The current uses of methyl bromide include the fumigation of homes and other structures for the control of termites and other pes

Methyl bromide Basic Attributes

Molecular Weight：

94.94

Exact Mass：

94.94

EC Number：

200-813-2

HScode：

2903399020

Characteristics

PSA：

XLogP3：

1.19

Appearance：

Methyl bromide appears as colorless highly toxic volatile liquid or a gas. Boiling point 3.56°C (38.41°F). Usually odorless, but has a sweetish chloroform-like odor at high concentrations. Used as an insecticide, a rodenticide, a fumigant, a nematocide, a chemical intermediate and as a fire extinguishing agent. (EPA, 1998)

Density：

1.7 g/cm³

Melting Point：

-93.66 °C

Boiling Point：

3.5 °C

Flash Point：

-34 °C

Refractive Index：

1.4432

Water Solubility：

H2O: 1.522 g/100 mL

Storage Conditions：

2-8°C

Vapor Pressure：

1420 mm Hg ( 20 °C)

Vapor Density：

3.3 (20 °C, vs air)

Toxicity：

Inhalation-Rat LC50: 302 PPM/ 8 hours; Oral-Rat LD50: 214 mg/kg

Flammability characteristics：

Combustible in case of high temperature, open flame and aluminum powder; burning produces toxic bromide fumes

Explosive limit：

~16%

Odor：

Usually odorless; sweetish, chloroform-like odor at high concentrations

Taste：

Burning taste

Safety Information

Hazard category：

2.3

Transport codes：

UN 1062 2.3

wgk germany：

hazard class code：

23/25-36/37/38-48/20-50-59-68-38-20/22-11-67-66-19-12-39/23/24/25-23/24/25

safety instructions：

15-27-36/39-38-45-59-61-36/37-26-24-16-7

RTECS Number：

PA4900000

Marks：

T,N,Xn,F,F+

Storage features：

The warehouse is ventilated, low temperature and dry; lightly loaded and unloaded; stored separately from the combustion-supporting gas

Explosive characteristics：

Explosive when heated or exposed to sunlight; leaking emits highly toxic fumes; explosive when mixed with air

Stability/Shelf Life：

Stable. Incompatible with oxidizing agents, strong acids. This is an ozone-depleting chemical, and its use is restricted in many countries.

Precautionary statement(s)：

P210-P273-P281-P305 + P351 + P338

Hazard Statements：

H225-H302 + H332-H315-H319-H341-H373-H400-H420

Toxicity

Toxicity class：

highly toxic

Methyl bromide Use and Manufacturing

Methods of Manufacturing

There are two production processes for its preparation. (1) Sodium bromide method: Add sodium bromide and methanol sulphate to the reactor, and heat it with jacketed steam. When the reaction temperature is 60 ℃, control the reaction rate, distill off methyl bromide, and wash it off with alkali water (5% NaOH). The acid is dried and dehydrated by the drying tower, and then compressed to obtain the finished product. The CH3OH+NaBr+H2SO4→CH3Br+NaHSO4+H2O(2) bromine method reacts sulfur, methanol and bromine in the reaction kettle, and the reaction temperature is preferably 45 to 100°C. 4CH3OH+Br2+S→4CH3Br+SO2+2H2O

Uses

In ionization chambers.For degreasing wool.Extracting oils from nuts, seeds, flowers.Soil or space fumigant for insects, fungi, rodents.Methylating agent.Has been used as fire extinguishing agent.

Computed Properties

Molecular Weight:94.94
XLogP3:1
Exact Mass:93.94181
Monoisotopic Mass:93.94181
Heavy Atom Count:2
Complexity:2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes

Material

p-Xylene

m-Xylene

Sodium hydroxide

Trimethyl phosphate

o-Xylene

Downstream Products

Dimethyl disulfide