Carbon dioxide, lithium absorption

Anhydrous lithium hydroxide [1310-65-2], LiOH, is obtained by heating the monohydrate above 100°C. The salt melts at 462°C. Anhydrous lithium hydroxide is an extremely efficient absorbent for carbon dioxide (qv). The porous stmcture of the salt allows complete conversion to the carbonate with no efficiency loss in the absorption process. Thus LiOH has an important role in the removal of carbon dioxide from enclosed breathing areas such as on submarines or space vehicles. About 750 g of lithium hydroxide is required to absorb the carbon dioxide produced by an individual in a day. 

Properties oi the alkali hydroxides.—The alkali hydroxides are brittle, white, translucent solids with a more or less crystalline fracture, and fibrous texture. Sodium hydroxide deliquesces on exposure to the air, but it goes solid again owing to the formation of the carbonate by the absorption of carbon dioxide from the air. Lithium hydroxide is a little hygroscopic. Potassium hydroxide is even more deliquescent than the sodium compound but its carbonate is also deliquescent. The hydroxides are very solnble in water, and they also dissolve in alcohol. The reported numbers for the specific gravities22 of sodium hydroxide range from l-723 to 2T30 and for potassium hydroxide, from l-958 to 2 6. The best representative sp. gr. are 2"54 for lithium hydroxide 2130 for sodium hydroxide 2 044 for potassium hydroxide 3"203 (11°) for rubidium hydroxide and 3-675 (11°) for csesium hydroxide. 

In this study, the solubilities of carbon dioxide were represented by the Bunsen absorption coefficients and their values given in Table I for lithium chloride and in Table II for calcium chloride. The densities of salt solutions are... 

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