Hexamethylenetetramine Chemical reactions

Lastly, the KA-process (Bachmann process) is based on the reaction between hexamethylenetetramine dinitrate and ammonium nitrate with a small amount of nitric acid in an acetic anhydride solution. The chemical reaction is presented in Reaction 7.15. 

For example, novolacs are phenolic resins obtained by the condensation of phenol (trifunctional monomer) and formaldehyde (bifunctional monomer), using a stoichiometric excess of phenol so that formaldehyde is completely consumed without leading to gelation. In a second step, instead of directly adding the necessary formaldehyde, the polymer network is formed by reaction with hexamethylenetetramine (a condensation product of formaldehyde and ammonia usually called hexa), through a complex set of chemical reactions (Chapter 2). 

Fe(N03)3 solutions. Precipitates formed from 6.25 x I0 and 6.25 x lO M Fe(N03)3 solutions at 24 and 55 C showed the characteristic pattern of a-FeOOH, whereas in 6.25 x lO M, Fe(N03)3 solution at 24°C an amorphous precipitate was formed. a-Fe203 precipitated at 90 °C. The same authors proposed (Fig. 23.2) the mechanism of hydrolysis-precipitation from Fe(N03)3 solutions, consisting of the hydrolysis to monomers (A) and dimers (B), reversible, rapid growth of small polymers (C), the formation of slowly reacting large polymers (D), and polymerization and oxolation with the formation of a solid phase (E). XRD, FT-IR, and Mbssbauer spectroscopies were used to characterize hydrolytical solid products obtained by the hydrolysis of O.l M Fe(N03)3 aqueous solutions at 90°C in the presence of hexamethylenetetramine (HMTA) [24,25]. HMTA generates OH ions at an elevated temperature in accordance with the chemical reactions... 

Two-Stage Resins. The ratio of formaldehyde to phenol is low enough to prevent the thermosetting reaction from occurring during manufacture of the resin. At this point the resin is termed novolac resin. Subsequently, hexamethylenetetramine is incorporated into the material to act as a source of chemical cross-links during the molding operation (and conversion to the thermoset or cured state). 

Sommelet process org chem The preparation of thiophene aldehydes by treatment of thiophene with hexamethylenetetramine.. so-mal ya, pra-s3s ) Sonnenschein s reagent analychem A solution of phosphomolybdicadd that forms a yellow precipitate with alkaloid sulfates. z6n-3n,shTnz r5,a-j3nt) sonocatalysis chem 1. Initiation of a catalytic reaction by irradiation with sound or ultrasound. 2. Use of sound to impart catalytic activity to a chemical compound. san-3-k3 tal-3-s3s)... 

Hexamethylenetriperoxidediamine is the only organic peroxide which has been considered seriously as an explosive. Its explosive properties commend it, but it is too reactive chemically and too unstable to be of practical use. It is most conveniently prepared by treating hexamethylenetetramine with hydrogen peroxide in the presence of citric acid which promotes the reaction by combining with the ammonia which is liberated. 

Phenylethylamine has been made by a number of reactions, many of which are unsuitable for preparative purposes. Only the most important methods, from a preparative point of view, are given here. The present method is adapted from that of Adkins,1 which in turn was based upon those of Mignonac,2 von Braun and coworkers,3 and Mailhe.4 Benzyl cyanide has been converted to the amine by catalytic reduction with palladium on charcoal,5 with palladium on barium sulfate,6 and with Adams catalyst 7 by chemical reduction with sodium and alcohol,8 and with zinc dust and mineral acids.9 Hydrocinnamic acid has been converted to the azide and thence by the Curtius rearrangement to /3-phenyl-ethylamine 10 also the Hofmann degradation of hydrocinnamide has been used successfully.11 /3-Nitrostyrene,12 phenylthioaceta-mide,13 and the benzoyl derivative of mandelonitrile 14 all yield /3-phenylethylamine upon reduction. The amine has also been prepared by cleavage of N- (/3-phenylethyl) -phthalimide 15 with hydrazine by the Delepine synthesis from /3-phenylethyl iodide and hexamethylenetetramine 16 by the hydrolysis of the corre-... 

When Jacobsen s epoxidation was fully described in 1998-99, the Casiraghi method was abandoned in favour of an even older method discovered in the 1930s by Duff. The remarkable Duff reaction uses hexamethylenetetramine, the oligomer of formaldehyde and ammonia, to provide the extra carbon atom. The now otherwise unknown Duff worked at Birmingham Technical College. Later in 1972, a William E. Smith, working in the GEC chemical laboratories... 

The initial process for creating plastic is very complex. Plastic is made from synthetic resins. The atoms that make up the molecules of synthetic resins are composed of carbon, hydrogen, oxygen, and nitrogen. Process technicians make synthetic resins by combining chemical compounds such as ammonia, benzene, hexamethylenetetramine, or a variety of other hard-to-pronounce chemicals. The reaction that takes place creates synthetic links between molecules called monomers. 

Schuphan, L., Westphal, D., Haque, A. and Ebing, W., 1981. Biological and chemical behaviour of perhalogenmethylmercapto fungicides Metabolism and in-vitro reactions of dichlofluanid in comparison with captan. Am. Chem. Soc., Symposium Series, 158, 85-96. Schweinfurth, H. A. and Giinzel, P., 1987. The tributyltins Mammalian toxicity and risk evaluation for humans. Proc. Oceans, 87, 1421-37. Scott, C. R. and Wolf, P. A., 1962. Antibacterial activity of a series of quaternaries prepared from hexamethylenetetramine and halohydro-carbons. Appl Microbiol. 10, 211-16. 

Hexamethylenetetramine (Chapter X TII), which is produced by the reaction of formaldehyde and ammonia, must receive special consideration in any discussion of formaldehyde substances. Although this compound, (CHileXi, is a distinct chemical entity, it plays an important industrial role as a special form of formaldehyde. Chemically it is an aimiiono analogue of the cyclic formaldehyde polymers in which trivalent nitrogen has replaced bivalent oxygen. 

Phenolic resins are obtained by polymerizing phenol with formaldehyde. When polymerized at low pH (i.e., acidic reaction medium), the resultant material is a straight-chain polymer, normally called novolac. However, under basic conditions, a higher-branched polymer called resole is formed. To cure novolac, a cross-linking agent, hexamethylenetetramine, is required, which has the following chemical formula ... 

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