Drying by distillation

Commercial carbon tetrachloride is dried by distilling and rejecting the first 10 per cent, of the distillate. 

Technically pure toluene can be conveniently dried by distilling 350 ml. from a litre flask and rejecting the first 50 ml. 

The chloroform is dried by distillation, and the fraction boiling at 60-61° is used. 

The benzene can be dried by distilling on a steam bath until the distillate is no longer milky. About r 5 per cent of the benzene is distilled. 

The benzene is dried by distilling the first 10% and using the residue directly. 

Commercial ethanolamine (Carbide and Carbon Chemicals Corporation) was dried by distillation with a small amount of benzene and redistilled b.p. 70-72°/12 ram. 

Chloral [75-87-6 302-17-0 (hydrate)] M 147.4, b 98°, pK 10.04. Distd, then dried by distilling through a heated column of CaS04. 

It is preferable to use ether subjected to final drying by distillation from lithium aluminum hydride. 

A good commercial grade of ethylene chloride, b.p. 83-84°, was used. It is dried by distilling a portion. 

Formamide is distilled under vacuum before use. /-Butyl alcohol may be dried by distillation from sodium or calcium hydride (3 g/100 ml). All other reagents should be dry. 

Dried by distillation under reduced pressure and storage for several days over Linde Molecular Sieves Type 4A. 

Dried by distillation from, and storage over, calcium hydride. 

No difference in yield is noticed in using the ordinary pure grade of carbon tetrachloride and (he sulfur-free C.P. grade. It is easily dried by distilling the commercial product and rejecting the first 10 per cent of the distillate. 

The nitrobenzene is dried by distillation under atmospheric or reduced pressure, by rejecting the first 5 per cent of the distillate. 

The benzene was dried by distillation, the first portion of the distillate being discarded. 

Triethylamine was dried by distillation from phosphorus pentoxide at atmospheric pressure. The checkers used reagent-grade material available from Eastman Organic Chemicals. 

Dimethyl sulfoxide (supplied by Aldrich Chemical Company, Inc.) was dried by distilling over calcium hydride at 5 mm. 

Toluene (99.9%) is purchased from Fisher and dried by distillation under argon from sodium benzophenone ketyl. 

Pentane was dried by distillation from aluminum chloride. 

B. Di-tert-hutyl malonate. A 1-1. three-necked flask is fitted with a thermometer, a mercury- or rubber sleeve-sealed mechanical stirrer, a reflux condenser protected by a calcium chloride guard tube, and a dropping funnel (either pressure-equalized or protected by a calcium chloride guard tube). A mixture of 100 ml. (about 1 mole) of tert-butyl alcohol, dried by distillation from sodium,2 and 80 ml. (0.63 mole) of dry dimethylanilinc (Note 5) is placed in the flask, the stirrer is started, and a solu-... 

A 5-1. three-necked flask is fitted with a mechanical rubbersleeved stirrer, a dropping funnel, and a reflux condenser capped with a calcium chloride tube leading to a gas-absorption trap.2 The system is flame-dried, and the flask is charged with 308 g. (1 mole) of dibromohydrocinnamic acid (Note 1) and 800 ml. of dried (by distillation) thiophene-free benzene. While the dibromohydrocinnamic acid is maintained in suspension by stir-... 

The toluene is dried by distillation the first 10 per cent is discarded and the remainder is stored over sodium until used. 

Tne recovered benzene and excess iso-propyl alcohol may be dried by distillation and used in a subsequent run. 

Commercial nitrobenzene is dried by distillation under reduced pressure until the distillate is clear. The residue is suitable for use without other treatment. 

Nitromethane was dried by distillation of a 10 1 mixture of nitromethane and trifluoroacetic anhydride and collection of the center fraction that distilled at 100°C. 

Dichloromethane was dried by distilling from calcium hydride. The checkers used dichloromethane (reagent grade) kept over 4 A molecular sieves for 2 days to obtain the same results. 

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