Hexamethylenetetramine Analysis

Acid—Base Chemistry. Acetic acid dissociates in water, pK = 4.76 at 25°C. It is a mild acid which can be used for analysis of bases too weak to detect in water (26). It readily neutralizes the ordinary hydroxides of the alkaU metals and the alkaline earths to form the corresponding acetates. When the cmde material pyroligneous acid is neutralized with limestone or magnesia the commercial acetate of lime or acetate of magnesia is obtained (7). Acetic acid accepts protons only from the strongest acids such as nitric acid and sulfuric acid. Other acids exhibit very powerful, superacid properties in acetic acid solutions and are thus useful catalysts for esterifications of olefins and alcohols (27). Nitrations conducted in acetic acid solvent are effected because of the formation of the nitronium ion, NO Hexamethylenetetramine [100-97-0] may be nitrated in acetic acid solvent to yield the explosive cycl o trim ethyl en etrin itram in e [121 -82-4] also known as cyclonit or RDX. 

In the third presentation, Mark, a leading expert in the area of structural analysis by X-ray crystallagraphy, expressed the opposite view. Comparing hexamethylenetetramine and cellulose, he proposed that cellulose consists of small units held together by forces "comparable by type and magnitude to the inner molecular forces". Mark concluded, "The whole crystallite appears as a large molecule" (61). 

Mark s paper, titled "Die roentgenographishe Ermittlung der Struktur organischer besonders hochmolekularer Substanzen", systematically compared the analysis of hexamethylenetetramine... 

Structures determined by X-ray analysis. Abbreviations pip = piperidine Mejpip = 2,6-dimethylpiperidine (CH NH = ethyleneimine (aziridine) (CH = hexamethylenetetramine (CH N-jH = dabconium ion. 

Rapaport and Solyanik (168) have developed a rapid method of refractometric determination of 23 mixtures containing anesthesin, barbamyl, bromcamphor, bro-misoval, camphor, antipyrine, amidopyrine, acetalsali-cylic acid, barbital, codeine, salol, terpin hydrate, hexamethylenetetramine, and phenobarbital. The method described is suitable for analysis of pharmaceutical mixtures containing compounds which are insoluble in water and soluble in ethanol. A mixture of 2 pharmaceuticals (0.1 g) is dissolved in 1 ml. ethanol and np of this solution is determined. One component is... 

Anchoring polymers are prepared from chloromethylated styrene-divinylbenzene copolymers of either 1 equiv Cl/g or 4 equiv Cl/g capacity. These resins arc stirred for 24 h in refluxing CHC13, with either 1,4-diazabicyclo[2.2.2]octane, hexamethylenetetramine, or TMEDA. The polymers are filtered off, washed with ClIClj, acetone and Et20, then dried overnight under vacuum at 25 °C. Nitrogen elemental analysis and chloride ion titration gives a value of 80-90% quaternarization. 

Two reports have been published on the sonochemical preparation of nanosized ceria, Ce02 [133, 134]. Zhu and coworkers [133] synthesized nanocrystalline ceria (Ce02) particles via sonochemical and microwave assisted heating routes from aqueous solutions containing (NH4)2Ce(N03)6, hexamethylenetetramine and poly (ethylene glycol) (PEG Mw = 19,000). Analysis of the results showed that the products had a uniform shape, narrow size distribution, and displayed conspicuous quantum size effects. 

Even relatively complex molecules may be packed together to give simple structures if they are themselves highly symmetrical in form. The structure of hexamethylenetetramine, C6H12N4, is an example of this and is also of historic interest as the first organic structure to be completely determined by X-ray analysis. The molecule of this compound has the symmetrical configuration shown in fig. 14.02a> with six... 

Some reported examples of the use of PBC analysis to predict crystal morphology include hexamethylenetetramine (Hartman and Perdok, 1955), calcium sulphate (gypsum) (van Rosmalen, Marchee and Bennema, 1976), anthracene (Hartman, 1980), magnesium hydrogenphosphate (newberyite) (Boistelle and Abbona, 1981), sodium sulphite and potassium sulphate (Follner and Schwarz, 1982), succinic acid (Davey, Mullin and Whiting, 1982), sucrose (Aquilano et al, 1983). 

A study [12] of the novolak-hexamethylenetetramine reaction by differential thermal analysis and thermogravimetric analysis supports the view that the cross-linking reaction proceeds through dibenzylamines. 

Experience in the Avriter s laboratoly indicat-es that the accuracy of this procedure is improved if the acid hexamethylenetetramine solution is not owed to boil. This may be carried out in a satisfactory manner by piac ingthe beater on a steam-heated sand bath (135 140 C) under a fume hood. The tune required for analysis may be reduced if water is not added to the evaporating solution. With an approximately 0.5 g sample of hexamethylenetetramine, the liberated formaldehyde is completely aporized in appro.rimately 2 to 3 hours. Methyl orange is recommended as a titration indicator. 

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