Phosphorus pentoxide drying agent

Drying agents may be divided broadly into (a) those which combine with water reversibly and (6) tho.se which react chemically with water by a non-revcrsible process giving rise to a new water-free compound. Sodium, calcium carbide and phosphorus pentoxide belong to the latter class and will be discussed in Section 11,39. 

Suitable drying agents are, for example, calcium chloride, silica gel, molecular sieves, calcium hydride, or phosphorus pentoxide however, their use must be adapted to the requirements and conditions of each polymerization. 

Phosphorus pentoxide is a very effective drying and dehydrating agent, also converts acids to their anhydrides. 

Which drying agent is more efficient, Drierite or phosphorus pentoxide ... 

The xylene is dried over sodium and distilled from it. The ethyl propionate is dried over phosphorus pentoxide, more of the drying agent being added from time to time until some solid phosphorus pentoxide remains. The ester is then decanted into a flask containing fresh phosphorus pentoxide and fractionated. The fraction boiling at 98 99°/745 mm. is collected. 

The absolute humidity of air refers to the mass of water vapour actually present in unit vol., and it is determined by passing a known vol. of air over a suitable drying agent—calcium chloride, phosphorus pentoxide, etc. (1. 7, 2)—and... 

Alternative drying agents for chloroform are phosphorus pentoxide, calcium sulphate, or powdered Type 4A molecular sieve. 

Fused calcium chloride and phosphorus pentoxide can also be used as a drying agents. 

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