Кобальт карбонил химические свойства, назначение, производство
Химические свойства
Cobalt carbonyl is a pyrophoric (spontaneously flammable in air), red-orange (when pure) to dark-brown crystalline solid.
Физические свойства
Orange crystals; density 1.78 g/cm3; melts at 5l°C; decomposes above this temperature; insoluble in water; soluble in most organic solvents including alcohol, ether, carbon disulfide.
Использование
- Cobalt carbonyl [Co2(CO)8] is commonly used as a catalyst in the hydroformylation (oxo reaction) of alkenes.
- Along with pyridine, it can be used as a catalyst in the carboxylation of alkenes into corresponding acids and esters.
- It is employed as a key precursor in the preparation of cobalt platinum (CoPt3), cobalt sulfide (Co3S4) and cobalt selenide (CoSe2) nanocrystals.
- It is also used as a reagent in Pauson-Khand cyclizations and Nicholas reaction.
Подготовка
Cobalt octacarbonyl is prepared by the reaction of finely divided cobalt with carbon monoxide under pressure:
2Co + 8CO → Co2(CO)8
The compound may be prepared in a similar way from cobalt(II) iodide. Also, it may be prepared by thermal decomposition of cobalt carbonyl hydride:
2HCo(CO)4 → Co2(CO)8 + H2
Опасность
Toxic by ingestion and inhalation.
Угроза здоровью
Dicobalt octacarbonyl exhibits moderate toxicityby inhalation route and somewhatlower toxicity by intraperitoneal and oralroutes. However, it is much less toxicthan nickel tetracarbonyl or iron pentacarbonyl.A 2-hour LC50 value in mice isreported as 27 mg/m3 (Lewis 1996). Anoral LD50 value in rats is within the rangeof 750–800 mg/kg. It decomposes, evolvingtoxic carbon monoxide.
Профиль безопасности
Poison by inhalation
and intraperitoneal routes. Questionable
carcinogen. Decomposes in air to form a
product that ignites spontaneously in air.
"hen heated to decomposition it emits
acrid smoke and fumes. See also
CARBONYLS and COBALT
COMPOUNDS.
Возможный контакт
This material is used as a catalyst for a number of reactions. It is also used in antiknock gasoline and for high-purity cobalt salts.
Перевозки
UN3124 Toxic solids, self-heating, n.o.s., Hazard Class: 6.1; 6.1-Poisonous materials, 4.2-Spontaneously combustible material. Technical Name Required. UN3190 Self-heating solid, inorganic, Hazard Class: 4.2; Labels: 4.2-Spontaneously combustible material, Technical Name Required. UN1325 Flammable solid, organic, n.o.s. Hazard Class: 4.1; Labels: 4.1-Flammable solid
Методы очистки
It forms orange-brown crystals on recrystallisation from n-hexane under a carbon monoxide atmosphere [Ojima et al. J Am Chem Soc 109 7714 1987; see also Hileman in Preparative Inorganic Reactions, Ed. Jolly, Vol 1 p 101 1987].
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. Decomposes on exposure to air or heat (@ ~52°C) producing toxic fumes of cobalt and oxides of carbon
Кобальт карбонил препаратная продукция и сырье
сырьё
препарат