Nylon basic hydrolysis

Patty acids can be determined easily by GC and HPLC. Hydrolysis of polysorbate 80 will release oleic acid. Thus, if a suitable hydrolysis procedure can be established to release oleic acid quantitatively, eitlier a GC or an HPLC technique can be performed to determine tlie amount of polysorbate 80 in Nasonex. Approximately 9 g of Nasonex and an equivalent amount of polysorbate 80 standard were transferred into two separate flasks, followed by the addition of 1.0 mL of 1 N NaOH, and mixed well. The mixture was heated in a water batli at 70°C for 3 h. The sample and standard solutions were removed from tlie water batli and cooled to room temperature. An equal volume of acetonitrile was added to tlie solutions, mixed well, and centrifuged. The supernatant portion is filtered tlirough a 0.2-ttm nylon syringe filter. The hydrolysis can also be carried out under acidic conditions. Most of the procedures in tlie acidic conditions were similar to basic hydrolysis. The only difference was adjustment of tlie filial H2SO4 concentration to 1 A and extending the hydrolysis tune to 24 h. 

In the case of nylon-6,6, basic hydrolysis is the preferred treatment. Depolymerization occurs by reaction with sodium hydroxide, hexamethylene diamine and sodium adipate being the initially formed products. In a second step, the latter is converted into adipic acid via acidification with HC1. 

Chemical depolymerization of polyamides is mainly carried out by hydrolysis. Acid hydrolysis of nylon-6 allows the starting monomer, e-caprolactam, to be recovered. Likewise, basic hydrolysis of nylon-6,6 leads to hexamethylene diamine and adipic acid. Degradation of polyamides by ammonolysis has also been reported as an interesting alternative for the chemical recycling of nylon-6 and nylon-6,6 mixtures. 

Pure xylan is not employed in industry. but crude xylan or pentosans are of industrial importance. Xylan has been proposed as a textile size but is not employed as yet for this purpose.130 Perhaps the largest use of pentosans is in their conversion to furfural, which has many applications and serves as the source of other furan derivatives. At the present time, large quantities of furfural are used in the extractive purification of petroleum products, and recently a large plant has been constructed to convert furfural by a series of reactions to adipic acid and hexamethylene-diamine, basic ingredients in the synthesis of nylon. In commercial furfural manufacture, rough ground corn cobs are subjected to steam distillation in the presence of hydrochloric acid. As mentioned above, direct preferential hydrolysis of the pentosan in cobs or other pentosan-bearing products could be used for the commercial manufacture of D-xylose. 

---