Adipic 2,5-diamino

Fig. 7.6. Industrial-scale processing condensation of adipic acid (B) and ammonia to adipic acid diamide (D) and its thermal dehydration to adipic acid dinitrile (C). On a very large scale, adipic acid dinitrile is hydrated to give 1,6-diamino-hexane ("hexamethylenedi-amine ), which is further processed to furnish nylon-6,6 ("nylon").

The world-wide production of PA (excluding fibers) in 1997 was 1.6x10 t, with a 75 % use of casting processed materials. For food contact articles the following can be used as starting materials straight chain u -amino acids (C6-C12) and their lactams adipic acids, azelaic acids, sebacic acids, dodecane dicarboxylic acids and heptadecane-dicarboxylic acids salts with hexamethylenediamine isophthalic acid, bis(4-aminocy-clohexyl)-methane, 2,2-bis(4 -aminocyclohexyl)-propane, 3,3 -dimethyl-4,4 -diamino-dicyclohexyl-methane, terephthalic acid or its methylester, l,6-diamino-2,2,4-tri-methylhexane, 1,6-diamino-2,4,4-trimethylhexane, l-amino-3-amino-methyl-3,5,5-tri-methylhexane. 

Nylon 6,6 and nylon 6 are polyamides. These polymers are used in carpets, in hosiery, and in certain cases as engineering plastics. Nylon 6,6 8.19, is the condensation product between adipic acid and 1,6-diamino hexane. Nylon 6 8.20 is made from caprolactam by ring-opening polymerization. 

When adipic acid (hexanedioic acid) and hexamethylenediamine (1,6-diamino-hexane) are mixed, a salt is obtained. On heating, this salt is converted into Nylon 66, a high-molecular-weight compound of formula (Ci2H2202N2)n. (a) Draw the structural formula for Nylon 66. To what class of compounds does it belong (b) Write an equation for the chemistry involved when a drop of hydrochloric acid makes a hole in a Nylon 66 stocking. 

Adipic acid and 1,6-diamino-hexane are the monomers that polymerize by condensation to iform nylon-6,6. You are probably familiar with nylon fabrics, such as those used to make tents, but nylon can be molded into solid objects too. 

Hygrine occurs in Erythroxylon truxillense Rusby leaves in extractable quantities, but not in those of other tropane-forming species. It could be equally well regarded either as an intermediate substance or an unmanageable side product. Difficulties in realizing its oxidation have led to the suggestion of yet another possible precursor of hyoscyamine in diamino-adipic acid. When this is done the difficulty of the intermediate oxidation disappears, but the origin of the diaminoacid puts another in its place. 

In recent years synthetic fibers have been made, by synthesizing long molecules in the laboratory. One of these, which has valuable properties, is nylon. It is the product of condensation of adipic acid and diamino-hexane. These two substances have the following structures ... 

This limitation is overcome when the elastomer is cast from a mixture consisting of a linear polyester or poly ether, diisocyanate and glycol or diamine. In this process, the hydroxy-terminated polymer (e.g., poly(ethylene adipate) or poly(oxytetramethylene) glycol) is treated with an excess of diisocyanate (e.g., naphthylene 1,5-diisocyanate, tolylene diisocyanate or diphenylmethane 4,4 -diisocyanate). The product is a pre-polymer which is, in effect, a mixture of isocyanate-terminated polymer and unreacted diisocyanate. The pre-polymer is then mixed with either a glycol (e.g., 1,4-butanediol or 1,6-hexanediol) or diamine (which is usually a deactivated amine such as 3,3 -dichloro4,4 -diamino-diphenylmethane (MOCA)). The mixture is poured into a heated mould where it quickly sets. After about 30 mins the casting is removed from the mould and cured at about 110°C for 24 hours. 

Synthesis of Heterocyclic Compounds. Thionyl chloride and pyridine at elevated temperatures convert diarylalkenes, styrenes, and cinnamic acids to benzo[i>]thiophenes and adipic acid to 2,5-bis(chlorocarbonyl)thiophene. Additional heterocycles which have been prepared include thiazolo[3,2-a]indol-3(2//)-ones, oxazolo[5,4- /]pyrimidines, and 1,2,3-thiadiazoles. Treatment of 1,2-diamino aromatic compounds with thionyl chloride gives good yields of fused 1,2,5-thiadiazoles. ... 

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