Purification of Commercial Ether

The chief impurities in commercial ether are alcohol and water, with traces of aldehyde, methyl alcohol, acetone, due to it being made from methylated spirit. It may be purified as above. The presence of alcohol may be proved by shaking with a spirit soluble dye, e.g., aniline violet. If alcohol is present a blue solution is obtained. Water is detected by the cloudiness formed on mixing with carbon disulphide. 

—Ether, which is kept in air and light, develops peroxides which are explosive and remain in the residue after distillation. These can usually be removed by shaking with permanganate solution or with silver nitrate and caustic potash solutions. Ether, therefore, should always be distilled from a water bath to avoid heating the residue to a high temperature. 

Reaction LXXVIH. Action of Alkyl Halides on Alkali Alcoholates or Phenates. (P. R. S., 7, 135 J. C. S 2, 198 A., 78, 226 152, 164 B., 12, 116.)—This method is of importance as indicating the structure of ethers. It is applicable both in the aromatic and aliphatic series and can be used to obtain the ethers corresponding to the hypothetical di-and tri-hydric-alcohols, in which more than one hydroxyl group is attached to one carbon. 

A 500-c.c. round flask containing 200 c.cs. (excess) of absolute ethyl alcohol is attached to a reflux condenser, and 8 gms. (1 mol.) of sodium in thin slices or in small pieces of wire are added. When it has completely dissolved 31 gms. (1 mol.) of phenol and 75 gms, (excess) of dry ethyl iodide are added, and the whole refluxed on a water bath until the solution 

It should be noted that owing to the great affinity of the phenol for sodium, no sodium alcoholate remains to react with the ethyl iodide. Diethyl ether, however, may be prepared in a similar manner, using the same quantities of sodium, alcohol and ethyl iodide as above. The ether and excess of alcohol are distilled off and the ether separated from the alcohol by the addition of salt solution. Anisole (phenylmethyl ether, B.P. 154°, see p. 218) can also be prepared in a similar way, using corresponding quantities of methyl alcohol and methyl iodide. The alkyl iodides give the best yields, but alkyl chlorides can also be employed. 

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Purification of commercial ether. Divide the contents of a Winchester bottle of ether into approximately two equal volumes and shake each in a large separatory funnel with 10-20 ml of the above iron(n) sulphate solution diluted with 100 ml of water. Remove the aqueous solution and combine the two ether portions in a clean dry Winchester bottle and add 100-200 g of anhydrous calcium chloride. Allow this mixture to stand for 24 hours with occasional shaking the water and ethanol are largely removed during this period. Filter the ether through a large fluted filter paper into another clean dry Winchester... 

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