No abstract

Recently Vaughn and Danehy7 have shown that calcium acetylide may be used in this synthesis in place of sodium acetylide with comparable results.The principal reaction occurring in this synthesis of alkynes and the only * Paper XIX on the chemistry of alkyl acetylenes and their addition compounds; previous paper,

The absorption of sodium hydroxide by cotton has been shown to take place very rapidly, and to change only slightly over a period of two or three days.2. Previous treatment of the cotton by sodium hydroxide solution of concentration greater than 5% increases its power of absorption. The maximum effect is produced when the concentration of the modifying solution is 20% or greater.3. The absorption curves indicate that the action of sodium hydroxide solution of concentration 4 to 5% is the formation of the compounds (C6Hio06)u-NaOH from native cotton and (06 05) 2•2 from mercerized cotton.Grand Falls, Newfoundland

Catalysis of the water-gas reaction thus being excluded from consideration, it has been shown that the acceleration of the reaction C + C 0 2 = 2 CO, and therefore the acceleration of the reaction, C + 2 H2O = COZ + 2 Hz, may be ascribed to increased adsorption of carbon dioxide by the carbon surfaces in presence of active catalytic agents. 6. Adsorption measurements have been shown to confirm this view. 7. The results obtained have been considered in view of the proposed existence of a surface complex C,O,, and have been found to agree with this conception. PRINCETON, NEW JERSEY. [(!ONTRTBUTION FROM THE CHEMICAL LABORATORY OF THE UNIVERSITY OF NOTRE DAME.]

HE chief methods of estimating the peroxides in un-T saturated organic compounds are based on the oxidation of either potassium iodide or a ferrous salt by the peroxides. For example, Marks and Morrell (2) use a solution of potassium iodide in glacial acetic acid. After the iodine is liberated, the solution is diluted with water and the free iodine titrated with standard sodium thiosulfate. A considerable error may be introduced by the addition of iodine to the unsaturated linkage, particularly since the rate of addition in many cases is greatly accelerated by the presence of peroxides.Yule and Wilson (3) estimate peroxides in cracked gasoline by shaking it with an acidified solution of ferrous sulfate and ammonium thiocyanate in a 50 per cent acetone-water mixture. The ferric thiocyanate which is formed is titrated with a standard titanous chloride solution. Several improvements in this method are desirable. Instead of using as the solvent 50 per cent acetone, in which most hydrocarbons have a limited solubility, it is preferable to use a solvent which is miscible with hydrocarbons. It is also desirable to estimate the ferric thiocyanate formed by the peroxides by some means other than standard titanous chloride, in order to avoid the difficulties inherent in the use of this reagent. Since minute quantities of ferric thiocyanate produce an intense coloration when in solution, it is possible and advantageous to determine the ferric thiocyanate colorimetrically. The convenience and rapidity of colorimetric procedures are well known.In selecting a solvent there are two important factors to be considered :(1) the solvent should dissolve an appreciable quantity of the inorganic salts used, and (2) the solvent should be miscible with the organic compounds which are to be analyzed. Absolute methyl alcohol meets these requirements. Preparation of the ReagentThe reagent is prepared by dissolving 5 grams of ammonium thiocyanate and 5 cc. of 6 N sulfuric acid in 1000 cc. of absolute methyl alcohol, and then saturating the solution with pure ferrous ammonium sulfate. Shaking the solution with the finely pulverized salt for a few minutes is sufficient. The faint pink color which is formed may be evaluated by comparing it with a suitable color standard. The results of analyses may then be corrected for the trace of ferric thiocyanate present in the reagent. The faint pink color in the reagent does not deepen appreciably over a period of an hour or so. The usefulness of the reagent may be extended to much longer periods by keeping the reagent in an inert atmosphere. Preparation of the Color StandardSolutions of ferric thiocyanate in absolute methyl alcohol are used as color standards. In order to make the colorimetric comparisons conveniently and accurately, the concentration of the standard solution should not differ more than two-or threefold from that of the solution whose color is being determined. Furthermore, since solutions of ferric thiocyanate in methyl alcohol fade slowly on standing, the standard solutions should be...