Calcium hexamine

Reduction of dibenzothiophene with sodium in liquid ammonia has been shown to be sensitive to the experimental methods employed however, the major product is usually 1,4-dihydrodibenzothiophene. 27 -28i The electrochemical reduction of dibenzothiophene in ethylene-diamine-lithium chloride solution has been shown to proceed via stepwise reduction of the aromatic nucleus followed by sulfur elimination. In contrast to the reduction of dibenzothiophene with sodium in liquid ammonia, lithium in ethylenediamine, or calcium hexamine in ether, electrolytic reduction produced no detectable thiophenol intermediates. Reduction of dibenzothiophene with calcium hexamine furnished o-cyclohexylthiophenol as the major product (77%). Polaro-graphic reduction of dibenzothiophene 5,5-dioxide has shown a four-electron transfer to occur corresponding to reduction of the sulfone group and a further site. ... 

Cyclodehydration of 2-phenylthiocyclohexanone with a variety of reagents yielding 1,2,3,4-tetrahydrodibenzothiophene (64) as an oil has been reported,and represents the simplest way of obtaining this material (88%). Alternatively, reduction of 4-keto-1,2,3,4-tetrahydrodibenzothiophene under Huang-Minlon conditions affords 64 in high yield.Trace amounts of 64 were detected in the reduction of dibenzothiophene with calcium hexamine and during electrolysis in ethylenediamine-lithium chloride solution (Section III, C,4). Peracetic acid oxidizes 64 to its sulfone (65%), which... 

In 1945, Campbell and McDermott [32] found that the reduction of diaUcylacety-lenes by calcium hexamine [CafNI-Isle] in diethyl ether yielded the corresponding trans alkenes. In 1984, Benkeser and Belmonte [33] reported results from detailed studies of the reduction of internal and terminal alkynes by calcium in a mixture of methylamine and ethylenediamine (1 1 v/v). For example, reduction of 4-oc-tyne gives a mixture of isomeric trans octenes in 75% overall yield it includes trans-2-, 3-, and 4-octenes in the ratio 1 9 88. Treatment of 1-heptyne, a terminal alkyne, with a fivefold excess of calcium produces 70% of a mixture containing 87% n-heptane, 7% tra s-2-heptene, and 3% 1-heptene. 

Procedure. Pipette 25 mL of the test solution (which may contain both calcium and lead at concentrations of up to 0.01 M) into a 250 mL conical flask and dilute to 100 mL with de-ionised water. Add about 50 mg of methylthymol blue/potassium nitrate mixture followed by dilute nitric acid until the solution is yellow, and then add powdered hexamine until the solution has an intense blue colour (pH ca 6). Titrate with standard (0.01 M) EDTA solution until the colour turns to yellow this gives the titration value for lead. 

The historical link between the use of HMT to alleviate or prevent the effects of phosgene is a long one. In designing respirators to defend against phosgene during WWI, a range of compounds was examined. For example, soda lime (a mixture of sodium hydroxide and calcium hydroxide) proved effective, while phenol and sodium phe-nolate were also effective and British Phenolate Helmet (P Helmet) was first used on December 15, 1915. This was followed by the Phenolate Hexamine Helmet (PH Helmet) from early 1916 onwards. The PH Helmets comprised a flannel sack which had been dipped in a mixture of... 

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