Hexamethylenetetramine, formation

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. 

Reaction of alkyl halides 1 with hexamethylenetetramine 2 (trivial name urotropine) followed by a hydrolysis step, leads to formation of primary amines 3 free of higher substituted amines. This method is called the Delepine reaction, a comparable method is the Gabriel synthesis. 

Tracer Studies on the Nitro lysis of Hexamine to RDX and HMX. The formation of RDX and/or HMX molecules from the nitration or nitrolysis of Hexamethylenetetramine (Hexamine) is a complex process and has been postulated to take place via two separate paths. One involves the selective cleavage of the Hexamine molecule to the appropriate cyclic nitramine (RDX, HMX or both) depending on the specific... 

This chapter emphasizes the recent mechanistic and kinetic findings on phenolic oligomer syntheses and network formation. The synthesis and characterization of both novolac- and resole-type phenolic resins and dieir resulting networks are described. Three types of networks, novolac-hexamethylenetetramine (HMTA),... 

Normally the reaction Is useful for the conversion of alkyl halides to primary amines without concomitant formation of secondary amines.29 Treatment of polymer 17 with hexamethylenetetramine in a mixture of ethanol/THF afforded an insoluble resin. Using diazabicyclooctane (DABCO), we demonstrated that the reaction could be limited to attack by a single nitrogen in a multifunctional amine, so we did not anticipate crosslinking via bis-quat salt formation. Hydrolysis of 2 with anhydrous HC1 in ethanol generated free amino groups as evidenced by a positive ninhydrin test, but quantitative hydrolysis could not be achieved and the product remained insoluble. One would have expected a simple bis-quat to hydrolyse and open the crosslinked structure. 

Hexamethylenetetramine this ammonia precursor does not cause fibre swelling and the unfixed dyes are removed efficiently at pH 6.5, compared with pH 8.5 with ammonia, thus causing less damage to the wool. However, the hydrolysis of this compound (Scheme 12.6) results in the formation of formaldehyde and this can modify the hue of certain dyes [2]. 

The early addition of Dimedon is reported234 to depress the formation of hexamethylenetetramine from formaldehyde in the presence of ammonia. O Dea282 found that the activated methylene center, sometimes formed in periodate oxidations of carbohydrates, reacts appreciably with the formaldehyde formed, thus giving low yields of apparent formaldehyde. He was able to depress this side reaction by the use of lowered temperatures and by the addition of benzaldehyde or of p-hydroxybenzaldehyde. The analyses for formaldehyde have often been more successful at a pH of 7.5 than at lower pH values.57, 68 59a 60 264... 

The reaction mixture is dehydrated at temperatures as high as 160°C (higher temperatures can be tolerated than with resoles). The prepolymer is cooled, crushed, blended with 5-15% hexamethylenetetramine, (CH2)6N4, and sold to the fabricator. Hexamethylenetetramine, referred to as hexa, is the product of the reaction of 6 mol of formaldehyde and 4 mol of ammonia. Curring occurs rapidly on heating with the formation of both methylene and ben-zylamine crosslinking bridges between benzene rings. The crosslinked network is pictured as... 

Compound Name Ammonium Hydroxide Hexamethylenetetramine Ammonium Acetate Ammonium Bifluoride Ammonium Sulfamate Ammonium Sulfamate Ammonium Benzoate Ammonium Bicarbonate Ammonium Dichromate Ammonium Bifluoride Ammonium Carbonate Ammonium Chloride Ammonium Citrate Ammonium Citrate Ammonium Pentaborate Ammonium Dichromate Nickel Ammonium Sulfate Ferric Ammonium Citrate Ferric Ammonium Oxalate Ferrous Ammonium Sulfate Ammonium Fluoride Ammonium Silicofluoride Ammonium Formate Ammonium Gluconate Ammonium Bicarbonate Ammonium Bifluoride Ammonium Sulfide Ammonium Hydroxide Ammonium Thiosulfate Ammonium Thiosulfate Ammonium Iodide Ferrous Ammonium Sulfate Ammonium Lactate Ammonium Lactate Ammonium Lauryl Sulfate Ammonium Molybdate Ammonium Chloride Nickel Ammonium Sulfate Ammonium Nitrate Ammonium Nitrate-Urea Solution Ammonium Oleate... 

According to Singh [45] under the influence of the nitracidic ion (H2NOf)), hexamethylenetetramine first undergoes hydrolysis identical to that leading to the formation of (VI). On hydrolysis the ion (Via) would be formed or on further heterolysis the ion (VIb), then (Vic). The latter would undergo nitrolysis to form cyclonite, methylnitramine (Villa) and formaldehyde ... 

The solvent influences on the complex formation and stability have been reviewed by Golub et al.194 Several monomeric complexes of Hg(SCN)2 with N, O, P, As and S donor ligands are known with terminal Hg—SCN bonds.224-2 Some thiocyanate-bridged dimeric complexes of mercury(II) are also known.225,226 Recently the isolation of a mercury(II) thiocyanate complex with hexamethylenetetramine with exclusively N-bonded SCN groups has been published (Figure 9).233 The compounds (CH2)6N4-Hg(SCN)2 and (CH2)6N4-2Hg(SCN)2 exhibit covalently bonded Hg—s.394,595... 

Butlerov, Alexander M.(1828-1886). Russian chemist known for his numerous works in organic chemistry. He discovered formaldehyde in 1859 and studied its reactions with ammonia, including the formation of hexamethylenetetramine Refs l)H.M.Leicester, JChemEduc 17, 203 9 (1940) 2)Walker, Formaldehyde(1953), 2... 

Methanal and ammonia react by a different course with the formation of a substance known as hexamethylenetetramine ... 

Acetic Anhydride, Hexamethylenetetramine Acetate, and Nitric Acid. Explosive mixture due to formation of acetyl nitrate.4... 

The most important reaction examples for the formation of IVW-acetals involve formaldehyde because it tends more than most other carbonyl compounds to undergo additions (Section 9.1.1). With ammonia formaldehyde gives hexamethylenetetramine (Figure 9.24). This compound contains six lYW-acetal subunits. 

Fig. 9.24. Mechanism for the formation of hexamethylenetetramine from ammonia and formalin.

Bimethylamine absorbs nitrogen, splitting off water in ratios that likewise indicate the formation of hexamethylenetetramine. 

Ethylamine does not react with nitrogen, but it gives off a quantity of hydrogen which indicates the formation of a body homologous to hexamethylenetetramine. 

Alternatively, we could attempt to re-estimate the enthalpy of formation of 1,1-dipiper-idinobutane, the purported contaminant in l-(l-butenyl)piperidine. However, since this gem-diamine is present in a thermochemically ill-defined amount (4-6%) and the only other gem diamines for which there are chronicled enthalpies of formation are bis(dimethylamino)methane, hexamethylenetetramine (1,3,5,7-tetraazaadamantane) and the fluorinated CFn(NF2)4 (n — 0,1 and 2), this re-estimation hardly seems advisable. Our prejudice is thus to disregard the enthalpy of formation data for l-(l-butenyl)piperidine altogether. 

The reaction of alkenes with hexamethylenetetramine in anhydrous hydrogen fluoride results in the formation of 1,3,5-trisubstituted hexahydro-1,3,5-triazines. These hexahydrotriazines are readily hydrolyzed under mild conditions to yield y-fluoroalkylaniines. " " ... 

---