Adsorbates caprolactam

Reflux extraction of additives and wax from polyolefins was reported [116]. Subsequently, the additives were adsorbed onto an adsorbent (Florisil) and the wax was removed from the extract before chromatography. Boiling extractions of SBR are described in ASTM D 1416-89 1 g of rubber is extracted by boiling in two 100 mL portions of 75/25 vol% isopropyl alcohol/toluene. Reflux heating with strong solvents, such as THF, dichloromethane or chloroform has been reported [117]. Reflux extraction has also been used for the 3 h extraction of caprolactam and oligomers from PA6 in boiling methanol. 

The solution composition and the nature of particles adsorbed and reduced on the electrode, as well as e-caprolactam additive, affected the electroreduction of cadmium ions [232, 233]. 

The ammoximation of cyclohexanone to cyclohexanone oxime (Scheme 9.1) is an important industrial process, because the oxime is an intermediate for the formation of s-caprolactam, the monomer for nylon-6, that is currently manufactured on a scale of 4 Mton p.a. TS-1 catalyses the ammoximation of ketones, including cyclohexanone, in liquid phase in the presence of ammonia and hydrogen peroxide. The reaction proceeds through hydroxylamine as an intermediate, which is generated at the active site via complexes of framework titanium with ammonia and hydroperoxide. The hydroxylamine then reacts with cyclohexanone molecules that are weakly adsorbed within the pores or can diffuse out into solution. The reaction is a general one, and can be apphed to the ammoximation of a wide range of ketones. 

In the course of formation of polymers, some monomer remains in the cured adhesive. This monomer can diffuse to the boundary, plasticizing faulty surface layers of the polymer and adsorbing on the substrate surface [13]. Monomer at the boundary between the adhesive and the substrate inevitably decreases the adhesion strength. For example, by electron microscopy one can observe single crystals of caprolactam on the surface of PC-4 polycaprolactam [14], Removal of the polymer surface layer usually results in noticeable increase of the adhesion strength in the course of bonding [15],... 

Ogawa et al. have reported the cyclodehydration of 6-aminocaproic acid adsorbed on zeolite, silica gel or alumina in refluxing toluene to yield a-caprolactam [85]. 

Figure 6.2. Elution profile of lactate dehydrogenase from porcine muscle and total protein with 0.1 M KCl from a Blue Sepharose column with adsorbed poly(N vinyl caprolactam) (a thermosensitive polymer with transition temperature about 35°C). The crude extract was applied on a column at 40°C. Arrow indicates when the column was cooled to room temperature and elution was continued at this temperature. Experimental conditions column 1.3 x 0.9 cm I.D., flow rate 0.17 ml/min, fractions collected every 5 min. Redrawn from ...

---