By Action of Iodine on Hydrogen Sulfide

Hydrazine dihydrochloride, 92 Hydrazine residues, recovery of, 92 Hydrazine sulfate, 90, 92 Hydrazoic acid, 77, 78 Hydriodic acid, 157, 159 by action of iodine on hydrogen sulfide, 157 constant boiling, 158 fuming, 162 stabilization of, 159 Hydrobromic acid, 151, 152, 155 constant boiling, 155... 

Hydriodic acid, 1 157, 159 by action of iodine on hydrogen sulfide, 1 157 constant-boiling, 1 158 fuming, 1 162... 

Derivation (1) By passing hydrogen with iodine vapor over warm platinum sponge and absorption in water. (2) By the action of iodine on a solution of hydrogen sulfide. 

All A-halo compounds can be readily determined by analysis based on their oxidizing action. They liberate two equivalents of iodine from acidified potassium iodide solution almost instantaneously (1 mmole of A-monohalo compound is equivalent to 20 ml of O.In-thiosulfate solution). The liberation of iodine from hydrogen iodide involves production of the amine or amide parent of the halo compound. Sodium sulfite and hydrogen sulfide also reduce N-halo compounds. UV and IR spectroscopic methods have been worked out for determination of JV-halo compounds.399... 

As already oudined, inhibition is essentially complete when caused by reagents that react with sulfhydryl groups (for example, p-chloro-mercuribenzoate, p-mercuribenzoate, o-iodosobenzoate, L-ascorbic acid silver, cupric, and mercuric ions iodine, and ferricyanide) this inactivation can be reversed to some extent by hydrogen sulfide and by cysteine. Lineweaver—Burk graphs have shown that the action of L-ascorbic acid is noncompetitive, and L-ascorbic acid acting in the presence of cupric ions probably causes formation of an inactive cuprous-enzyme. The action of p-chloromercuribenzoate on barley beta-amylase has been shown to be a competitive inhibition. In contrast, the soya-bean p-chloromercuribenzoate inhibition is noncompetitive, and the extent of inhibition is inversely related to the concentration of acetate ion. The latter exhibits a protective effect, and there... 

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