IODOFORM. Tri-iodomethane, CHIN was discovered by Serullas in 1822. Will formed by the interaction of ethyl alcohol and iodine in the presence of caustic alkalis. Acetone, acetaldehyde and many other compounds may also yield varying quantities of iodoform when treated with iodine and caustic alkalis or car bonates. Iodoform has also been obtained from, derivatives of acetylene; and of late years it has been formed from ammonium iodide in the presence of potassium hypoiodite, potassium carbonate and ammonia.
On a commercial scale iodoform is prepared by the addition of iodine to an aqueous solu tion of sodium carbonate in the presence of ethyl alcohol. The temperature of the reaction mixture is maintained at 70°40° C. The main portion,of the iodine is converted into iodoform, which being insoluble forms a yellow precip in tate. The remainder of the iodine dissolves n the reaction mixture as sodium iodide. From the latter the iodine is recovered by the use chlorine, and converted into iodoform with an additional quantity of sodium carbonate and alcohol. A repetition of this process will in crease the yield of iodoform. In this acetone may be substituted for ethyl alcohol, and potassium carbonate for sodium A second process, extensively employed at the present time, consists in the electrolysis of a water solution of potassium iodide, alcohol or acetone, and an alkaline hydroxide or car bonate, at a temperature of 65° C.
Iodoform crystallizes in lemon-yellow plates. It has a persistent unpleasant odor, melts at 119° C. and dissolves in absolote alcohol, ether, carbon bisulphide and other solvents. With
alcoholic potash it yields potassium formate and potassium iodide. In the presence of arsenious acid and sodium hydroxide it is converted into methylene iodide, and with phosphorus penta chloride it yields chloroform. With dry silver nitrate iodoform forms an explosive mixture.
Iodoform was first employed in the treat ment of wounds in 1880. When brought in contact with wounds or sores it acts as a good antiseptic and promotes healing. The action is probably due to the liberation of iodine and other products at the temperature of the body. It is extensively used the treatment of scrofula, goitre, cancer and in syphilitic and tuberculous ulcerations. When iodoform is taken in large doses into the system, it may pro duce symptoms of poisoning, nausea and vomit ing, headache, sleepiness, hallucinations and even death.
• The objectionable odor of iodoform has been masked by combining it with a variety of substances such as volatile oil of camphor, balsam of Peru and paraformaldehyde. A number of good iodoform substitutes have been prepared. Some of these are related to iodo form both in composition and in their mode of decomposition. Iodoformin, for example, is a compound of iodoform and hexamethylene tetramine; it liberates iodoform when it is used as a dressing on wounds. Iodol (tetra iodo-pyrrol), and aristol (dithymol di-iodide) are also more or less related to iodoform. Among other substitutes for iodoform may be mentioned euro,phen, vioform, xeroform, novi form, loretin and airol.