Eicosane, structure

Cold-water frsh like salmon are rich in omega-3 fatty acids, which have a double bond three carbons in from the noncarboxyl end of the chain and have been shown to lower blood cholesterol levels. Draw the structure of 5,8,11,14,17-eicosapentaenoic acid, a common example. (Eicosane = C20H42)... 

Another cobalt derivative with CoN6 coordination is [Co(sep)]3+. This is the complex formed by Co(III) with the ligand 1,3,6,8, 10,13,l,6,19-octaazabicyclo[6.6.6]eicosane, which is related to the diamino-sarcophagine seen for the chromium complexes, and is called sepulcrand . Figure 90 shows the octahedral structure of this complex.135... 

In order to investigate the structure of crosslinked polyethylene by, 3C NMR the model compound l,l,2,2-tetra(tridecyl)ethane, i.e. two molecules of n-C27H56 linked at the C-14 atoms, was prepared. The tertiary 13C-14 atoms give rise to a resonance signal at 39.5 ppm. Spectra of long chain n-paraffins eicosane (C20H42) and hexacosane (C26H54) exposed to 5 MGy y-radiation above their respective... 

In the past several years organic chemists have attempted to synthesize some unusual cycloalkanes not found in nature. Dodecahedrane, a beautifully symmetrical compound composed of 12 five-meinbered rings, is one such molecule. It was first prepared at Ohio State University in 1982. The lUPAC name for dodecahedrane is undecacyclo[9.9.9.0 .a - .(f V 0. 0 0 ° ". 0 .0 ]eicosane, a name so complex that few trained organic chemists would be able to identify its structure. 

They have a different structure, although they both have the same molecular formula. One is called normal butane, abbreviated to -butane the other may be called isobutane or 2-methylpropane - the latter name describes the structure of the compound, as you will see later. These compounds are isomers of one another. They are not the same compounds and have different melting points, boiling points and solubilities. Isomers are compounds which have the same moiecuiar formuia, but different moiecuiar structures. After butane, the longer the carbon chain of an alkane, the more structurai isomers are possible for a particular molecular formula. For example, there are 75 decanes (C10H22) and over three-hundred-thousand eicosanes (C20H42) ... 

Since Cjo eicosane is very similar to the n-octoxymethyl group in chemical structure, there should be an interaction between Cjo eicosane and the C,2 side branch. This can be confirmed by the upper curve of Figure 7. This curve of Figure 7 reveals that below about 110°C, the layer spacing of the 1 1-mixture does not change practically, but at about 110°C it jumps far more than the lower cuive without C20 eicosane. This phenomenon indicates that at that temperature C20 eicosane starts to penetrate into the C,2 side chain phase and the side chains phase increase in volume and hence in the layer spacing. 

The simulations described above were performed at constant density, i.e., a volume was imposed on the system irrespective of the resulting pressure or chemical potential. MD simulations performed at constant chemical potential, where the confined liquid is in equilibrium with a vapor or bulk liquid phase, have also been performed. Simulations with free surfaces, i.e., with vapor/polymer interfaces, allow for the study of the equilibrium liquid-vapor interface structure and the calculation of the surface tension, a thermodynamic property fundamental to the understanding of the behavior of a material at interfaces. An MD study of the equilibrium liquid-vapor interface structure and surface tension of thin films of n-decane and n-eicosane (C20H42) has been performed in Ref. 26. The system studied consisted of a box with periodic boundary conditions in all directions. The liquid polymer, however, while fully occupying the x and y dimensions, occupied only a fraction of the system in the z direction, resulting in two liquid-vapor interfaces. The liquid phase ranged from about 4.0 to 7.0 nm in thickness. Simulations were performed at 400 K for both decane and eicosane, with additional decane simulations at 300 K. A similar system of tridecane molecules, using a well calibrated EA force field, has been studied at 400 K and 300 K in Ref 32. 

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