Лития бромид химические свойства, назначение, производство
Химические свойства
White cubic crystals; hygroscopic; refractive index 1.784; density 3.464 g/cm3; melts at 550°C; vaporizes at 1,265°C; highly soluble in water (145g/100g at 4°C), much greater solubility in hot water (254g/100g at 90°C); soluble in methanol, ethanol and ether; slightly soluble in pyridine; vapor pressure of aqueous solutions at 52 and 68% concentrations at 25°C are 5 and 0.7 torr, respectively.
Физические свойства
White cubic crystals; hygroscopic; refractive index 1.784; density 3.464 g/cm3; melts at 550°C; vaporizes at 1,265°C; highly soluble in water (145g/100g at 4°C), much greater solubility in hot water (254g/100g at 90°C); soluble in methanol, ethanol and ether; slightly soluble in pyridine; vapor pressure of aqueous solutions at 52 and 68% concentrations at 25°C are 5 and 0.7 torr, respectively.
Использование
As humectant, in air-conditioning systems. An aqueous solution of lithium bromide containing about 50 % lithium bromide is used as an absorbent in large-scale absorption air conditioning equipment. Lithium bromide is also used in limited amounts by the pharmaceutical industry for dehydrobromination of organic compounds to form olefins.
Определение
ChEBI: A lithium salt in which the counterion is bromide. The anhydrous salt forms cubic crystals similar to common salt.
Подготовка
Lithium bromide may be prepared by the reaction of lithium hydroxide monohydrate or lithium carbonate with hydrobromic acid. The resultant solution of lithium bromide may be evaporated and cooled to crystallize a hydrate of lithium bromide, the composition of which depends on the final temperature. The lithium bromide hydrate may be filtered from the mixture and carefully dried by the application of heat in a vacuum desiccator to avoid melting the hydrate.
Общее описание
LiBr/Chlorotrimethylsilane reagent participates in the conversion of alcohols to bromides.
Методы очистки
Crystallise it several times from water or EtOH, then dry it under high vacuum for 2 days at room temperature, followed by drying at 100o. Its solubility in H2O is 167% at ~20o, and 250% at ~100o. It is deliquescent and should be stored in a tightly stoppered vessel.
Лития бромид препаратная продукция и сырье
сырьё
препарат