Acyclic hydrocarbons analysis

Carbon-13 chemical shifts lend themselves conveniently to empirical analysis, because these shifts are easily measured and tend to have well-defined substituent effects. For saturated, acyclic hydrocarbons. Grant developed the formula... 

In contrast to the other large cats, the urine of the cheetah, A. jubatus, is practically odorless to the human nose. An analysis of the organic material from cheetah urine showed that diglycerides, triglycerides, and free sterols are possibly present in the urine and that it contains some of the C2-C8 fatty acids [95], while aldehydes and ketones that are prominent in tiger and leopard urine [96] are absent from cheetah urine. A recent study [97] of the chemical composition of the urine of cheetah in their natural habitat and in captivity has shown that volatile hydrocarbons, aldehydes, saturated and unsaturated cyclic and acyclic ketones, carboxylic acids and short-chain ethers are compound classes represented in minute quantities by more than one member in the urine of this animal. Traces of 2-acetylfuran, acetaldehyde diethyl acetal, ethyl acetate, dimethyl sulfone, formanilide, and larger quantities of urea and elemental sulfur were also present in the urine of this animal. Sulfur was found in all the urine samples collected from male cheetah in captivity in South Africa and from wild cheetah in Namibia. Only one organosulfur compound, dimethyl disulfide, is present in the urine at such a low concentration that it is not detectable by humans [97]. 

In this article (Part I) we have comprehensively reviewed the structural implications of the vibrational spectroscopic results from the adsorption of ethene and the higher alkenes on different metal surfaces. Alkenes were chosen for first review because the spectra of their adsorbed species have been investigated in most detail. It was to be expected that principles elucidated during their analysis would be applicable elsewhere. The emphasis has been on an exploration of the structures of the temperature-dependent chemisorbed species on different metal surfaces. Particular attention has been directed to the spectra obtained on finely divided (oxide-supported) metal catalysts as these have not been the subject of review for a long time. An opportunity has, however, also been taken to update an earlier review of the single-crystal results from adsorbed hydrocarbons by one of us (N.S.) (7 7). Similar reviews of the fewer spectra from other families of adsorbed hydrocarbons, i.e., the alkynes, the alkanes (acyclic and cyclic), and aromatic hydrocarbons, will be presented in Part II. 

Narumi, H. and Hosoya, H. (1980). Topological Index and Thermodynamics Properties. II. Analysis of Topological Factors on the Absolute Entropy of Acyclic Saturated Hydrocarbons. Bull. Chem.Soc.Jap., 53,1228-1237. 

A very comprehensive analysis of hydrocarbons (linear, acyclic and cyclic - steranes, hopanes etc.- isoprenoids) carboxylic acids, aldehydes, ketones and amines of the Vale do Paraiba and Marau oil shales was made by Chicarelli (27). An extremely careful quantitative and qualitative analysis of hydrocarbons (n-, iso-and anteiso-paraffins, isoprenoids, steranes and triterpanes) and carboxylic acids of Irati oil shale was presented by Carvalhaes (28). Nooner Oro (29) also reported data on the hydrocarbons pres ent in the Irati Formation. Polycyclic aromatic hydrocarbons in I-rati were determined by Youngblood Blumer (40). 

Conformational analysis of acyclic and alicyclic saturated hydrocarbons... 

Conformational analysis of acyclic and alicyclic saturated hydrocarbons 121 TABLE 8. Barriers (kcal mol" to ring inversion of polymethylcyclohexanes... 

Milligan, D. B., Wilson, P. F., Freeman, C. G. et al. (2002) Dissociative proton transfer reactions of H3 +, N2H+, and H3O + with acyclic, cyclic, and aromatic hydrocarbons and nitrogen compounds, and astrochemical implications. J. Phys. Chem. A106, 9745. Spanel, R, Pavlik, M., Smith, D. (1995) Reactions of H3O+ and OH ions with some organic molecules applications to trace gas analysis in air. Int. J. Mass Spectrom. Ion Processes 145, 177. 

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