Tetramines

Hydrolysis. Warm 0 5 g. with a few ml. of dil. HCl. The pungent odour of formaldehyde, produced by the hydrolysis of the tetramine, is readily detected ... 

Polyquinoxalines (PQ) have proven to be one of the better heat-resistant polymers with regard to both stabiUty and potential appHcation. The aromatic backbones are derived from the condensation of a tetramine with a bis-glyoxal, reactions first done in 1964 (61,62). In 1967, a soluble, phenylated version of this polymer was produced (63). The chemistry and technology of polyquinoxalines has been reviewed (64). 

Synthesis and Properties. A number of monomers have been used to prepare PQs and PPQs, including aromatic bis((9-diamines) and tetramines, aromatic bis(a-dicarbonyl) monomers (bisglyoxals), bis(phenyl-a-diketones) and a-ketones, bis(phenyl-a-diketones) containing amide, imide, and ester groups between the a-diketones. Significant problems encountered are that the tetraamines are carcinogenic, difficult to purify, and have poor stabihty, and the bisglyoxals require an arduous synthesis. 

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. 

Diamine curatives were the first cross-linking agents for fluorocarbon mbbers. They are corrosive to mild steel molds and have been replaced in many appHcations by the bisphenol or other more recent cure systems. Nevertheless, some diamines are stiU used for food-contact appHcations of fluorocarbon mbbers and in zinc-free cures of halobutyl mbbers for pharmaceutical stoppers. Methylene dianiline and triethylene tetramine are cross-linking agents for ethylene—acryflc elastomers. 

Polyamide Resins. Another class of polyamide resins, in addition to the Hquid resins used as epoxy hardeners, are the thermoplastic type, prepared generaHy by the condensation reaction of polyamines with polybasic fatty acids. These resins find use in certain hot-melt adhesives, coatings, and inks. Diamines, typicaHy EDA (233), are the principal amine reactant however, tri- and tetramines are sometimes used at low levels to achieve specific performance. 

Formylation of phenols and anilines with hexanethylane tetramine. 

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

Dinitrosopentamethylene- tetramine (II) Nitrosoamine N2 N0,H20, CH,NH2 160-200 210 Widely used in natural and synthetic rubbers. Some use in polyolefins. 

Modification of urea resins with certain organic bases, e.g. triethylene-tetramine, will give resins with basic groups which form ionisable salts in the presence of acids ... 

It will be noted here that such polymers have few single bonds in the repeating unit and contain a substantial proportion of linked ring structures. This has been taken further by the reaction of tetramines with tetra-acids, as indicated in Figure 29.18. 

Using a mononuclear tetramine a polycondensation very similar to that used with BBB can occur which leads to a ladder polymer of high structural perfection (BBL) Figure 29.20). 

Copper amine azide Copper tetramine nitrate Crotonaldehyde, stabilized Cyanogen bromide Cyanuric triazide... 

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. 

Ref 17). It reduces Fehling s soln (Refs 14 15) is decompd with Iron turnings in basic soln with loss of nitro groups (Ref 5) is hydrolyzed with K hydroxide in et ale to give K nitrite (Ref 15). The action of ammonia in eth gives a mixt of a pentanitrate, a tetrani-trate, and a mannitan tetramine,... 

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