PREPARATION of METHYL or ETHYL IODIDEfrom IODOFORM R. H. KIMBALL University of New Hampshire, Durham, New Hampshire
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in fairly rapidly,' while methyl iodide distils over through an efficient condenser and is collected under ice water. When no more methyl iodide is evolved, the product is separated from the water and run into a dry separatory funnel. Thirty cc. of concentrated sulfuric acid is added and shaken carefully but thoroughly with the crude halide; the funnel is cooled under the tap to remove the heat developed. The washing is repeated with a second portion of acid, then with a little sodium carbonate solution, the product dried over calcium chloride and distilled. The yield of colorless product boiling within 0.5' is about 336 grams or 78%. Ethyl iodide can be made by the same procedure, substituting 1040 to 1060 grams of commercial diethyl sulfate. The solution is boiled gently with a flame while running in the diethyl sulfate to distil over the ethyl iodide. The crude product should be shaken four times with 30 cc. portions of concentrated sulfuric acid, to remove the somewhat larger amounts of impurities * Dimethyl sulfate is poisonous, and corrosive on the skin. present. The yield is about 380 grams or 80% of colorlpparatus wet with it should he treated with dilute ammonia less product boiling within 0.3' range. vhich quickly destroys the substance. Disregarding the iodoform, the cost of 100 grams of R. F. WEINLAND AND &L Scmm, "Ueher eine einfache 3ildungs- und Darstellungs- Weise von Halogenalkylen." Bcr.. methyl iodide is 43 cents and ethyl iodide 57 cents by IS, 2327 (1905). this procedure.
HE iodoform which accumulates in many laboratories as a product of student preparations can be easily converted to methyl iodide or ethyl iodide ,y the following procedure. Three hundred forty grams of KOH pellets is added :o 1 liter of 95% ethyl alcohol and refluxed for a short ime; 400 grams of iodoform is added to the hot soluion in small portions. A vigorous reaction sets in Lfter each addition, the remaining KOH dissolves slowly md an abundant crystalline precipitate separates. rhe mixture is then refluxed for 3 hours, 1liter of water s added and about the same amount of alcohol is Willed off. The residue is cooled, acidified with dilute sulfuric acid, and filtered to remove considerable solid natter, which is washed free from iodide with cold water. The filtrate which should have a volume of about 2 iters is made alkaline with NaOH and heated on the steam bath. Several pieces of porous tile are added and %bout520 grams of commercial dimethyl sulfate* run
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