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Titolo:
Crystal structure of wax lamellar interfaces - A residual petroleum fraction characterized by electron crystallography
Autore:
Rademeyer, M; Dorset, DL;
Indirizzi:
Hauptman Woodward Med Res Inst Inc, Electron Crystallog Lab, Buffalo, NY 14203 USA Hauptman Woodward Med Res Inst Inc Buffalo NY USA 14203 alo, NY 14203 USA Rand Afrikaans Univ, Dept Chem & Biochem, ZA-2006 Auckland Pk, South Africa Rand Afrikaans Univ Auckland Pk South Africa ZA-2006 nd Pk, South Africa
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 22, volume: 105, anno: 2001,
pagine: 5139 - 5143
SICI:
1520-6106(20010607)105:22<5139:CSOWLI>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
INFRARED-SPECTROSCOPY; PARAFFIN; POLYETHYLENE; SCATTERING; DISORDER;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Dorset, DL Hauptman Woodward Med Res Inst Inc, Electron Crystallog Lab, 73High St, Buffalo, NY 14203 USA Hauptman Woodward Med Res Inst Inc 73 High St Buffalo NY USA 14203
Citazione:
M. Rademeyer e D.L. Dorset, "Crystal structure of wax lamellar interfaces - A residual petroleum fraction characterized by electron crystallography", J PHYS CH B, 105(22), 2001, pp. 5139-5143

Abstract

After a multicomponent paraffin assembly was constructed to model a petroleum residue wax (M-w/M-n = 1.009), its structure was characterized by electron crystallography. Consistent with a single lamellar spacing, two endotherms in a DSC scan are typical of paraffin chain solid solutions and represent the premelt transition to a "rotator" phase and the true melt. The average chain packing in the crystal structure is that of the paraffin n-C32H66,in space group Pca2(1) with a = 7.42, b = 4.96, and c = 85.0 Angstrom. An attempt to account for the lamellar disorder with a chain-end occupancy model based on the chemical distribution of chain lengths is only partially successful. A better fit is found when lower chain-end occupancies are used. This discrepancy could be due to conformational defects in which the chain end atoms do not lie on strict methylene subcell lattice sites.

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Documento generato il 01/04/20 alle ore 20:10:36