Bromoform, decomposition

In addition to the chemicals included on the other lists, the CDC also included heavy metals such as arsenic, lead, and mercury volatile solvents such as benzene, chloroform, and bromoform decomposition products such as dioxins and furans polychlorinated biphenyls (PCBs) flammable industrial gases and liquids such as gasoline and propane explosives and oxidizers and all persistent and nonpersistent pesticides. Agents included in this volume are limited to those that are most likely to pose an acute toxicity hazard. 

Tribromoacetic acid [75-96-7] (Br CCOOH), mol wt 296.74, C2HBr302, mp 135°C bp 245°C (decomposition), is soluble in water, ethyl alcohol, and diethyl ether. This acid is relatively unstable to hydrolytic conditions and can be decomposed to bromoform in boiling water. Tribromoacetic acid can be prepared by the oxidation of bromal [115-17-3] or perbromoethene [79-28-7] with fuming nitric acid and by treating an aqueous solution of malonic acid with bromine. 

SAFETY PROFILE Moderately toxic by ingestion. Questionable carcinogen with experimental carcinogenic data. Human mutation data reported. Compounds of this type are generally irritating and narcotic. See also BROMOFORM and CHLOROFORM. When heated to decomposition it emits toxic fumes of Cl and Br . 

DOT CLASSIFICATION 6.1 Label Poison SAFETY PROFILE Poison by inhalation and intravenous routes. Moderately toxic by ingestion and subcutaneous routes. An irritant. Questionable carcinogen with experimental carcinogenic data. Flammable when exposed to heat or flame. Moderately explosive by spontaneous chemical reaction. To fight fire, use water, CO2, dry chemical. Dehalogenation by reaction with alkalies, metals, etc., will produce spontaneously explosive chloroacetylenes. Violent reaction with NaK aUoy + bromoform. Mixtures with potassium are very shock-sensitive explosives. When heated to decomposition it emits highly toxic fumes of Cl". See also CHLORINATED HYDROCARBONS, ALIPHATIC. 

TETRACHLOROETHANE or sy/n-TETRACHLOROETHANE (79-34-5) Exposure to heat, light, air, moisture causes gradual decomposition and formation of hydrogen chloride. Reacts with strong caustics such as potassium hydroxide, forming explosive dichloroacetylene gas. Reacts violently with chemically active metals, sodium amide, bromoform,... 

Radicals react at the sulfur and decomposition ensues, generating an acyloxy radical. The acyloxy radical undergoes decarboxylation. Usually the radical then gives product and another radical that can continue a chain reaction. The process can be illustrated by the reactions with tri- -butylstannane and bromoform. 

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