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Alkanes, Isomers, and Nomenclature
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
Alkanes are non-polar molecules and generally insoluble in water or other highly polarized liquids. They have no functional group and, therefore, associate in the liquid phase only by van der Waals forces, leading to low boiling points relative to other organic molecules. Once the mass of the alkane is sufficiently large, however, the boiling point also becomes rather high. Indeed, very large alkanes are solids. Linear alkenes do not pack into a crystal structure very well due to conformational mobility (see Section 5.1), and the melting points tend to be rather low relative to other organic molecules, or relative to alkanes that are highly branched. The first number for the following alkanes is the boiling point and that in brackets [ ] is the melting point: propane = −42.1°C [−187.7°C]; pentane = +36.1°C [−129.7°C]; decane = +174.1°C [−29.7°C]; icosane = +343.8°C [+36.4°C]. What is the IUPAC name for the eleven-carbon linear alkane?
Asphalt Chemistry: An NMR Investigation of the Benzylic Hydrogens and Oxidation
Published in Arthur M. Usmani, Asphalt Science and Technology, 1997
R. W. Jennings, Jacqueline Fonnesbeck, Jennifer Smith, J.A.S. Pribanic
The assignments of the aliphatic carbon types in the solid-state spectra of the asphalt were made from the high-resolution liquid-state spectrum of the asphalt. Figure 7 shows a comparison of the aliphatic region of the solid-state spectrum of asphalt AAC-I with that of a high-resolution liquid-state spectrum of the asphalt [16]. In turn, the assignments of the carbon types in the liquidstate spectrum of an asphalt (Figure 8a) can be made by comparing the 13C NMR spectrum with that of a mixture of famesane and n-decane as shown in Figure 8b. Normal decane is a straight-chain alkane having eight methylenes and two terminal methyl groups. Famesane is an isoprenoid with five methyl groups (CH3), seven methylene carbons (CH2), and three methine carbons (CH). Both compounds are representative of common compound types in petroleum. This mixture was used by Netzel et al. [ 17] to assign the carbon types in the saturate fraction of shale oil (Figure 8c). As shown in Figure 8, the saturate components in asphalt and shale oil are very similar, that is, a mixture of isoprenoids and n- alkanes. This fact is not surprising because the biogenetic origins of the two materials are the same. It is not to be construed that the saturate components of asphalts (or shale oil) contain only famesane and //-decane, rather they contain a complex mixture of isoprenoids, other branched alkanes, and //-alkanes of different carbon numbers.
Influences of interconnection structure on the flow and heat transfer behaviors of the hydrocarbon fuel in parallel SCRamjet regenerative cooling channels
Published in Numerical Heat Transfer, Part A: Applications, 2023
Yuguang Jiang, Qi Wang, Qilin Zhou, Aijuan Wang, Wei Fan
n-Decane is used as the classic hydrocarbon fuel. In regenerative cooling, fuel experiences a wide range in temperature, from liquid to supercritical state under supercritical pressure. Three-parameter RK-PR equation of state is used to predict fuel density, considering its wide range of validity and ease of implementation [62]. δ1 is added beside parameters and b. δ2 is a function of δ1. or b is constant to each certain fluid.