Caprolactams, conformation

C, b.p. 81"C. Manufactured by the reduction of benzene with hydrogen in the presence of a nickel catalyst and recovered from natural gase.s. It is inflammable. Used as an intermediate in the preparation of nylon [6] and [66] via caprolactam and as a solvent for oils, fats and waxes, and also as a paint remover. For stereochemistry of cyclohexane see conformation. U.S. production 1980 1 megatonne. 

Warshel, Levitt, and Lifson derived a partially optimised consistent force field for amides and lactams (25). It is composed of an alkane part and an amide-part. The former was taken over from analogous earlier calculations for saturated hydrocarbons (17). The potential constants of the amide-part were optimised with the help of a large number of experimental frequencies (taken from TV-methylform amide, acetamide, iV-methylacetamide, and several deuterated species) as well as experimental geometry data for 7V-methylacet-amide. The resulting force field was used for the calculation of vibrational and conformational properties of 2-pyrrolidone, 2-piperidone and e-caprolactam. 

Conformational analysis of hexahydro-lH-azepin-2-one (caprolactam) confirms that it, like other five- to eight-membered lactams, has the cis conformation. The 1SN NMR shift for the seven-membered lactam in CHCI3 appears at 259.7 p.p.m. (upfield from HNO3) (76JA5082). Solvent shifts for the 1SN resonance of caprolactam have been determined (78MI51601). In TFA/(15N-H) is 92.5 0.5 Hz. 

Conformational analysis of hexahydro-lH-azepin-2-one (caprolactam) confirms that it. 

No.9, 1997,p.2067-75 STUDY OF THE CONFORMATIONS OF POLY(EPSILON-CAPROLACTAM) AND POLY(EPSILON-CAPROLACTAM)-POLYBUTADIENE BLOCK COPOLYMERS BY FTIR SPECTROSCOPY WITH PHOTOACOUSTIC DETECTION AND BY MICRO-RAMAN CONFOCAL SPECTROSCOPY Schmidt P Fernandez M R Pastor J M Roda J Czech Republic,Academy of Sciences ... 

FTIR spectroscopy with photoacoustic detection and micro-Raman confocal spectroscopy were used to study the conformations of poIy(epsilon caprolactam) and poly(epsilon-caprolactam)-polybutadiene block copolymers. In the block copolymers prepared by anionic polymerisation, the fraction of the planar conformation of poly(epsilon-caprolactam) chains decreased with increasing polybutadiene content. In the surface layers formed by rapid saw cutting and in the islands formed by microtome cutting, the content of the planar conformation was lowered. This was substantially increased by water treatment, especially at elevated temperatures. 15 refs. 

PJ Treado, MD Morris. Infrared and Raman spectroscopic imaging. Appl Spectrosc 29 1-38, 1994. P Schmidt, PJ Hendra. The application of Fourier-transform Raman spectroscopy to the determination of conformation in poly( -caprolactam) chains. Spectrochim Acta 50A 1999-2004, 1994. SPS Porto. Angular dependence and depolarization ratio of the Raman effect. J Opt Soc Am 56 1585-1589, 1966. 

Overberger et al [59] reported on the polymerization of D(-)-j3-methyl-e-caprolactam (XXVIII) into a crystalline polymer. A study of solution properties of the polymer has shown that no ordered helix structure exists, that solvatation of the amide carbonyl is independent of polymer conformation, and that each mer is solvated independently. — OA a, j3, 7, and 5 methyl-e-caprolactams have been successively polymerized by Overberger et al [60] OA a-methyl-e-caprolactam racemized under polymerization conditions, i.e. in the presence of sodium hydride catalyst. 

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