Hexamethylen tetramine

In the case of phenoHcs, it is possible to make linear thermoplastic polymers called novolaks, but this is done by reaction of less than one mole of formaldehyde with one mole of phenol the resulting resin has a large excess of free phenol. Usually in appHcation hexamethylene tetramine (HEXA) is added to the novolak. When heated, the HEXA breaks down into ammonia and formaldehyde and enters the reaction to form a light degree of cross-links in the final product. 

SOMMELET Aldehyde synthesis Aldehyde synthesis from primary alkyl halides with hexamethylene tetramine. 

Davey and Rutti (1976) studied the effeet of polyerystals growth on agglomeration of hexamethylene tetramine (HMT). Regular six member elusters were... 

Formic Aldehyde.—This aldehjde, H. CHO, is the lowest member of the aliphatic series. It has been found, but rarely, in the distUlation waters of a few essential oils. It can be identified by evaporation on a watsr-bath with ammonia when crystals of hexamethylene-tetramine are formed. 

The acid-catalyzed reaction occurs by an electrophilic substitution where formaldehyde is the electrophile. Condensation between the methylol groups and the benzene rings results in the formation of methylene bridges. Usually, the ratio of formaldehyde to phenol is kept less than unity to produce a linear fusible polymer in the first stage. Crosslinking of the formed polymer can occur by adding more formaldehyde and a small amount of hexamethylene tetramine (hexamine. 

Adhesion of melamine fiber to rubber matrices Rajeev et al. found that the dry bonding system consisting of resorcinol, hexamethylene tetramine and hydrated silica effectively reinforces EPDM [64], maleated EPDM [118], and nitrile mbber matrices [119]. They observed increase in tensile... 

Adamantane Hexamethylene tetramine Urea Figure 13-2. Adamantane, hexamethylene tetramine, and urea. 

Small amounts of pyridine bases increase the corrosion resistance of cement stone without any associated loss of strength [1016]. The use of nitrilo-trimethyl phosphonic acid and an adduct between hexamethylene tetramine and chlorinated propene or butene improves the adhesion to the metal, hardening times, mobility, and strength [ 1770]. The latter adducts are further claimed to be useful as additives in cementing oil and gas wells in salt-bearing strata [1768]. 

P. F. Tsytsymushkin, S. R. Khajmllin, A. P. Tamavskij, Z. N. Kudryashova, V. N. Levshin, B. V. Mikhajlov, Y. D. Morozov, and T. B. Kryukova. Plugging solution for oil and gas wells—contains plugging cement, nitrilo-trimethyl-phosphonic acid, product of reacting hexamethylene tetramine with chloro-derivatives unsaturated hydro-carbon(s) and water. Patent SU 1740629-A, 1992. 

Phenolic antioxidants in rubber extracts were determined indirectly photometrically after reaction with Fe(III) salts which form a red Fe(II)-dipyridyl compound. The method was applicable to Vulkanox BKF and Vulkanox KB [52]. Similarly, aromatic amines (Vulkanox PBN, 4020, DDA, 4010 NA) were determined photometrically after coupling with Echtrotsalz GG (4-nitrobenzdiazonium fluoroborate). For qualitative analysis of vulcanisation accelerators in extracts of rubbers and elastomers colour reactions with dithio-carbamates (for Vulkacit P, ZP, L, LDA, LDB, WL), thiuram derivatives (for Vulkacit I), zinc 2-mercaptobenzthiazol (for Vulkacit ZM, DM, F, AZ, CZ, MOZ, DZ) and hexamethylene tetramine (for Vulkacit H30), were mentioned as well as PC and TLC analyses (according to DIN 53622) followed by IR identification [52]. 8-Hydroquinoline extraction of interference ions and alizarin-La3+ complexation were utilised for the spectrophotometric determination of fluorine in silica used as an antistatic agent in PE [74], Also Polygard (trisnonylphenylphosphite) in styrene-butadienes has been determined by colorimetric methods [75,76], Most procedures are fairly dated for more detailed descriptions see references [25,42,44],... 

Hexamethylene tetramine Mercapto benzo thiazole Ortho-toluidine Para-toluidine... 

Hexamethylene tetramine (77 g., 0.55 mole) is dissolved in 200 ml. of chloroform, and 88 g. (0.5 mole) of 3-thenyl bromide (p. 96) is added as rapidly as possible with shaking (Note 1). A reflux condenser is attached, and the mixture is refluxed over a steam bath for 30 minutes. After being cooled, the mixture of chloroform and crystalline product (Note 2) is poured into 250 ml. of water and stirred until all the salt dissolves. The chloroform layer is separated and washed twice with 125-ml. portions of water, and the combined water extracts are steam-distilled. When the distillate comes over clear (about 1 1. of distillate is usually collected), it is acidified with a little hydrochloric acid (Note 3) and extracted with three 100-ml. portions of ether. After drying over Drierite, the ether is evaporated, and the residue is distilled. 3-Thenaldehyde is collected at 72-78°/12 mm. or 195-199°/744 mm., = 1.5860 (Note 4). The yield is 30-40 g. (54-71%). 

The compound, precipitated by interaction of hexamethylene tetramine and acidic 30% hydrogen peroxide, is a heat- and shock-sensitive powerful explosive when dry, much more shock sensitive than mercury fulminate. It explodes in contact with bromine or sulfuric acid. 

Zhan and Mao [60] used a simple, fast, and selective alternating current oscilloscop-ic polarographic titration method for the determination of primaquine and other alkaloid phosphate in pharmaceutical preparation. The titration was carried out with a standard lead solution in hexamethylene tetramine buffer containing 1 M sodium chlorate (pH 5.5). The results obtained by this method are comparable to those obtained by pharmacopoeial method. 

The RFK mechanism can be used with loomstate nylon and rayon fabrics, but polyesters will require a pre-treatment to achieve good adhesion. Hexamethylene tetramine should be avoided as the methylene donor when polyester fabrics are being used, as aminolysis of the ester linkages in the polyester can occur, which would cause significant degradation of fabric and adhesion to take place under severe service conditions. Hexamethylolmelamine ethyl ether should be used as the methylene donor in this case. 

Bachmann A process for making the explosive RDX. Hexamethylene tetramine is nitrated in acetic acid solution, using a mixture of ammonium nitrate and acetic anhydride. Invented by W. E. Bachmann at the University of Michigan during World War II. See also KA, Woolwich. 

Woolwich [Named after the British Government laboratory at Woolwich Arsenal, where it was invented] A process for making the explosive RDX by nitrating hexamethylene tetramine. 

Hexamethylene tetramine was made at 0°C from aqueous ammonia and formaldehyde (Meissner, Ind Eng Chem 46 724, 1954). The volume of the reactor was 1 liter. Find the order of the reaction with respect to NH3. 

Preparation of 3.5-dimethvl-4-hvdroxvbenzaldehvde. A mixture of 40.6g (0.33 mole) of 2-6-dimethylphenol and 46.2g (0.33 mole) of hexamethylene tetramine was covered with 500ml trifluoroacetic acid and the reaction mixture was refluxed overnight. After evaporation of the trifluoroacetic acid the residue was poured into 3L water and neutralized slowly with sodium carbonate. A brown oily solid was... 

---