Углерод тетрабромид

Описание

Carbon tetrabromide is considered a highly toxic chemical, may be fatal if inhaled, swallowed, or absorbed through skin. It is metabolized in vitro to produce carbon monoxide but the in vivo significance has not been established. Under anaerobic reducing conditions it forms complexes with ferrous cytochrome P450. Carbon monoxide is detected as a metabolic product of the interaction. Carbon tetrabromide’s production and use in organic syntheses may result in its release to the environment through various waste streams. Carbon tetrabromide has been isolated from red algae, Asparagopsis toxiformis, found in the ocean near Hawaii. It was detected in water from treated chlorinated seawater used for drinking at oil platforms. Occupational exposure to carbon tetrabromide may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. The general population may be exposed to carbon tetrabromide via ingestion of drinking water. Acute exposures to high concentrations may cause upper respiratory tract irritation and injury to lungs, liver (hepatotoxicity) and kidneys (nephrotoxicity). Chronic exposure effects at very low levels will be almost entirely limited to liver injury. It is a potent lachrymator even at low exposure concentrations. Although carbon tetrabromide may release bromine ions during metabolism, clinical bromism is not expected to occur.

Химические свойства

Carbon tetrabromide, is a colorless powder, white crystalline solid, or yellow-brown crystals. Slight odor

Использование

Carbon tetrabromide is used to a limited extent as a chemical intermediate. It has been isolated from red algae, Asparagopsis toxiformis, found in the ocean near Hawaii.

Определение

ChEBI: A one-carbon compound substituted by 4 bromo groups.

прикладной

Carbon tetrabromide (CBr4) is a multifunctional chemical reagent widely used in chemical and pharmaceutical industries. It mainly includes:
(1) As a thiophilic reagent, it promotes the one-pot oxidative condensation of amines with N,N'-disubstituted thioureas to give a variety of guanidine derivatives^[1].
(2) As a bromine radical precursor, used in the electrochemical radical bromination and cyclisation sequence of enoic acid to prepare bromomethylated γ-lactone derivatives^[2].
(3) As a precursor of hydrogen atom transfer reagent, used to generate aromatic carbonyl compounds^[3].
(4) As raw materials or intermediates for organic synthesis. Synthesis of N-sulfonylformamidine from CBr4 and formamide under UVA irradiation. Activated imine intermediates (Vilsmeier-Haack reagent derivatives) were obtained via a photoinduced reaction between CBr4 and formamide^[4].

Общее описание

A colorless crystalline solid. Much more dense than water and insoluble in water. Toxic by ingestion. Vapors are narcotic in high concentration. Used to make other chemicals.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

Carbon tetrabromide is incompatible with the following: Strong oxidizers, hexacyclohexyldilead, lithium .

Опасность

A poison; narcotic in high concentration. Liver damage, eye, skin, and upper respiratory tract irritant.

Угроза здоровью

Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Пожароопасность

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff may pollute waterways.

Профиль безопасности

Poison by subcutaneous and intravenous routes. Narcotic in high concentration. Mixture with Li particles is an impact-sensitive explosive. Explodes on contact with hexacyclohexylddead. When heated to decomposition it emits toxic fumes of Br-. See also CHLORINATED HYDROCARBONS, ALIPHATIC.

Экологическая судьба

Carbon tetrabromide inhibits protein synthesis and causes lipid peroxidation, both of which may be involved in cell injury or death mediated by free radicals.

Перевозки

UN2516 Carbon tetrabromide, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Методы очистки

Reactive bromide is removed from CBr4 by refluxing with dilute aqueous Na2CO3, then steam distilling, crystallising from EtOH, and drying in the dark under vacuum. [Sharpe & Walker J Chem Soc 157 1962.] It can be sublimed at 70o and low pressure. [Beilstein 1 IV 85.]

Несовместимости

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, lithium and hexacyclohexyldiilead, since violent reactions may occur.

Утилизация отходов

Purify by distillation and return to suppliers.