Production of polyamides

Emissions and consumptions from the production processes are summarised in Table 9.3, Table 9.5, Table 9.6, Table 9.7 and Table 9.8. 

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Two additional aromatic monomers have become commercially available for the production of polyamides y -xylylenediamine and... 

Of equally high industrial potential as intermediate chemicals are the various HMF-derived products for which well-worked-out, large-scale adaptable production protocols are available. Of these, the 5-hydroxymethyl-furoic acid, the 2,5-dicar-boxylic acid, the 1,6-diamine, and the respective 1,6-diol (framed in Scheme 2.12) are the most versatile intermediate chemicals of high industrial potential, as they represent six-earbon monomers that could replace adipic acid, alkyldiols, or hexamethy-lenediamine in the production of polyamides and polyesters. 

J. Bozi, Z. Czeg ny, and M. Blazs6, Conversion of the volatile thermal decomposition products of polyamide-6,6 and ABS over Y zeolites, Thermochim. Acta, 472(l-2) 84-94, June 2008. 

The use of certain vanadium compounds as catalysts has been increasing. Vanadium oxy trichloride is a catalyst in making ediylene-propylene rubber. Ammonium metavanadate and vanadium pentoxide aie used as oxidation catalysts, particularly in the production of polyamides, such as nylon, in the manufacture of H>S04 by the contact process, in the production of phdialic and maleic anhydrides, and in numerous other oxidation reactions, such as alcohol to acetaldehyde, anthracene to anthraquinone, sugar to oxalic acid, and diphenylamine to carbazole. Vanadium compounds have been used for many years 111 die ceramics field for enamels and glazes. Colors are produced by various combinations of vanadium oxide and silica, zirconia, zinc, lead, tin, selenium, and cadmium. Vanadium intermediate compounds also are used in the making of aniline Mack used by the dye industry... 

As any of the degradation reactions depends on the presence of a strong base, it is evident that neutralizing the base supports to the stabilization of the polymer. Thus, after having extracted the polymer either by water or by diluted acids, and after having dried the polymer, the decrease of the viscosity is much slower than in the case of non extracted polymer (103) (fig. 4). This makes it possible to apply the base catalysed polymerization for the production of polyamides for extruding and molding purposes. 

Leemann M, Hildebrandt V, Thiele H, Espig S. Production of polyamides by reactive distillation. WO 9943732, BASF AG, 1999. 

The selected scenario comprises the conceptual design of a polymerization process for the production of Polyamide-6 (PA6) from caprolactam [99, 104]. PA6 is a thermoplastic polymer with a world production capacity of more than 4 million tons per year (as of 2006). The most frequent use of PA6 is the production of fibers, which are used in home textiles, bath clothing and for carpet production. In addition, PA6 is used as an engineering construction material if high abrasion resistance, firmness, and solvent stability are required. Glass-fiber reinforced and mineral material-filled PA6 is a preferred construction material if a combination of rigidity, elasticity and refractory quality characteristics are required. 

Interfacial and solution polycondensations are commercially important. For example, an unstirred interfacial poly condensation reaction is utilized in the production of polyamide fibers. Another important application of interfacial polycondensation is the enhancement of shrink resistance of wool. The wool is immersed first in a solution containing one of the reactants and subsequently in another solution containing the other reactant. The polymer resulting from the interfacial reaction coats the wool and improves its surface properties. 

The commercial production of polyamide fibers began in the late 1930s in the United States and Europe. They are now produced worldwide. Nylon fiber producers in the United States in 2004 include Fiber Innovation Technology, Inc., Honeywell Nylon Inc., Invista Inc. (formerly DuPont Textiles Interiors), Nylstar, Inc., Palmetto Synthetics, Polyamide High Performance, Inc. (formerly Acordis), Solutia Inc., Unifi-Sans Technical Fibers, LLC, Universal Fiber Systems LLC, and Wellman, Inc. 

Phenol is a key industrial chemical however, the output of phenol from coal tar is exceeded by that of synthetic phenol. Phenol is used for the production of phenol-formaldehyde resins, while other important uses in the plastics field include the production of polyamides such as nylon, of epoxy resins, and polycarbonates based on bisphenol A and of oil-soluble resins from p-t-butyl and p-octyl phenols. Phenol is used in the manufacture of pentachlorophenol, which is used as a fungicide and in timber preservation. Aspirin and many other pharmaceuticals, certain detergents, and tanning agents are all derived from phenol, and another important use is in the manufacture of 2,4 dichlorophenoxyacetic acid (2,4-D), which is a selective weed killer. 

The use of water-containing miniemulsions (as described above) is Hmited to particular monomers for anionic polymerization. Since, in many cases, the initiator and active species are sensitive to water, the polymerization caimot be carried out in either water-in-oil or oil-in-water miniemulsions. The anionic polymerization of e-caprolactam in a non-aqueous miniemulsion was first reported in 2005 [103]. As the e-caprolactam monomer is hydrophilic, it was necessary to conduct the polymerization in an inverse miniemulsion. Unfortunately, the molten e-caprolactam-in-oil miniemulsions could not be stabilized efficiently, in contrast to dimethyl sulfoxide (DMSO)-in-oil miniemulsions. Therefore it was necessary to dissolve the e-caprolactam directly in DMSO, to form the dispersed phase. This synthetic strategy, which permitted the production of polyamide-6 nanoparticles, paved the way for a variety of water-sensitive reactions to be performed in miniemulsion nanodroplets, including the creation of hydrophihc polyurethane capsules and particles (see below). Subsequently, poly(e-caprolactone)... 

Etchells III AW, Mallon FK. Continuous process for the production of polyamides. US patent 7009028, assigned to E.I. du Pont de Nemours and Company, Wilmington, DE 2006. 

The Cg, Cio and C12 dibasic acids, as their butyl, hexyl, 2-ethylhexyl and octyl esters, are used as plasticizers for PVC, as engine lubricants and as intermediates in the production of polyamides, polyesters and polyurethane adhesives, coatings, fibres, inks and resins. The C2i-diacid is used primarily as a surfactant. By condensation with diamines, dimer acids are used extensively to furnish polyamide resins. Their major applications are printing inks, hot-melt adhesives and coatings. Reactive polyamides are used as curing agents for epoxy resins. 

More recently, some other monomers have been studied. The attraction of production of well-known materials from renewable feedstock led to studies of the use of ethanol for the production of bio-based polyethylene (PE), of caprolactam and muconic acid for the production of polyamides (PA) and of isobutylene for the synthesis of polyisobutylene. 

Adipic acid [ISV] (1877). (hexanedioic acid, 1.4-butanedicarboxylic acid) n. A dicar-boxylic acid used in the production of polyamides, alkyd resins, and urethane... 

Any nucleating agent conventionally used in the production of polyamides having a fine crystalline structure is suitable for polyphthalamide. ... 

In contrast to Achhammer [15, 16] and Straus and Wall [17, 18], many authors have detected not only carbon dioxide among the gaseous destruction products, but also large amoimts of ammonia [8-10, 20]. Ammonia can be formed [10] in the reaction of the terminal amino groups, this reaction proceeding even in the production of polyamides ... 

The yellow destruction products are apparently the result of interaction of amino groups with the oxidation products of polyamides, resulting in the formation of various p3rrrole derivatives [36]. 

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