Hofman reaction

The Hofman reaction on polyacrylamide is not a good method of preparing poly(vinyl amine). Nevertheless, it has been shown that with a small excess of NaOCl in a high concentration of sodium hydroxide at low temperature, it is possible to push the degree of amination of > 90%. The excess of NaOCl causes some degradation, but this is minimized if the temperature is controlled. The Mannich reaction of polyacrylamide with formaldehyde and dimethylamine has been studied with the aid of C n.m.r. Reaction rates, equilibria, and mechanism for the base-catalysed reaction were characterized. ... 

N. Hofman-Bang, The Iodine-Azide Reaction. C. A. Reitzels Forlag, Copenhagen, 1952. 

According to Hofman-Bang carbon sulfide selenide, CSSe, catalyzes the iodine-azide reaction but is at the same time decomposed with the formation of selenium. Experiments, in both this laboratory and that of Hofman-Bang have shown that carbon diselenide reacts with sodium azide (in aqueous or aqueous-alcoholic solution) with immediate precipitation of red selenium even at — 20° C. //a selena-triazole is formed in this reaction it must be extremely unstable. 

Kuznetsov (Ref 5) used Na azidodithiocarbonate and its derivs to increase the sharpness of color tests for example, in neutral soln the anhyd Na salt gives a yel color in the presence of Cu. Hofman-Bang (Ref 6) found that dil solns of Ij NaN2 were catalyzed by Na azidodithiocarbonate and proposed a chain reaction mechanism. The Na salt is used primarily to prepare the heavy... 

IV from acidic solution, Hofman-Bang and Holten were able to follow rates of formation under conditions similar to those of the catalysed reaction, and found the expression... 

However, Hofman-Bang reported a slow reaction of azide and tetrathionate. Both may be right, and reactions like (5) and (7)... 

The ammonia-oxidizing bacteria oxidize ammonia to nitrous acid via hydroxyl-amine (NH2OH) (Lees, 1952 Hofman and Lees, 1953) ammonia is first oxidized to hydroxylamine by the catalysis of ammonia monooxygenase (AMO) (Dua et al., 1979 Hollocher et al., 1981). In this reaction, molecular oxygen is utilized. Then, hydroxylamine formed is oxidized to nitrous acid by the catalysis of hydroxylamine oxidoreductase (HAO). 

Scheme 10.17. A representation of the thermal decomposition of a-chloro-A,A-dimethylamine with bond fragmentation to produce A,A-dimethylamine [(CH3)2NH], methanal (formaldehyde, H2C=0), and an alkene (2-methylpropene).The process is called the Hofinann-Lotfler-Freytag reaction (see Hofman, A. W. Chem. Ber., 1883,16, 558 and Loffler, K. Freytag, C. Chem. Ber., 1909, 42, 3427).

We selected a primary amine (octadecylamine) to improve the heat stability of our organ-oclay because primary amines do not undergo Hofman elimination reactions upon heating. Octadecylamine was protonated by HCl and dissolved in water for the eation exchange... 

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