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Asphaltene
Published in Jon Steinar Gudmundsson, Flow Assurance Solids in Oil and Gas Production, 2017
Saturates are non-polar hydrocarbons without double bonds, including straight-chain, branched alkanes and cycloalkanes (naphthenes). Cycloalkanes contain one or more rings, which may have several alkyl side chains. An alkyl is an alkane with one hydrogen molecule removed. For example, methyl has the reduced methane formula - $ - $ CH3 $ _{3} $ . The saturates are the lightest fraction of petroleum, their proportion (% wt.) decreasing with increasing molecular weight and density of crude oil.
Feedstock Composition
Published in James G. Speight, Refinery Feedstocks, 2020
By definition, the saturate fraction consists of paraffins and cycloparaffin derivatives (naphthene derivatives). The single-ring naphthene derivatives, or cycloparaffin derivatives, present in crude oil are primarily alkyl-substituted cyclopentane and cyclohexane rings. The alkyl groups are usually quite short, with methyl, ethyl, and isopropyl groups the predominant substituents. As the molecular weight of the naphthenes increases, the naphthene fraction contains more condensed rings with six-membered rings predominating. However, five-membered rings are still present in the complex higher-molecular-weight molecules.
Benzene, Aromaticity, and Benzene Derivatives
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
Virtually any functional group can be attached, but some appear more often. Several of the common functional groups are halogen, hydroxyl, amino, cyano, carboxylic acid, ester, aldehyde, ketone, methoxy, ethoxy, sulfonic acid, alkene, alkyne, and nitro. In addition, alkyl groups can be attached to a benzene ring such as methyl or ethyl. What is a representative structure for each of the functional groups from the preceding question when attached to a benzene ring? Name each one!
Synthesis and surface activity of novel high energy nitrate surfactants
Published in Journal of Dispersion Science and Technology, 2023
Haiyan Li, Rui Yang, Zhen Dong, Yifei Liu, Zhiwen Ye
In this work, 4-amino-1,2,4-triazole that has one of the highest nitrogen contents among triazole compounds, high enthalpy of formation and good detonation performance is used as the raw material. The synthesis of energetic surfactants is illustrated in Scheme 1. 4-amino-1,2,4-triazole is the hydrophilic group in the surfactant, and the long carbon chain is the hydrophobic group. The synthesis of triazole nitrates was designed and carried out. First, 4-amino-1-alkyl-1,2,4-triazole was produced by alkylation. Then, by converting the halide into nitrate anion, the product salts were prepared. This reaction process is stable and obtains a high yield. The physical and chemical properties of the product salts were investigated. In addition, another high energy surfactant was synthesized using this approach (Scheme 2). Compared to the product obtained by Scheme 1, the product obtained by Scheme 2 has high energy and high stability. Using methylimidazole as the hydrophilic group in the surfactant, 1-(12-hydroxy dodecyl)-3-methyl imidazolium bromide was generated through alkylation. Finally, by nitrating the halide, it was converted to 1-(12-nitrooxy dodecyl)-3-methyl imidazolium nitrate. The products were characterized by 1H-NMR, 13C-NMR, MS and IR spectroscopies.
Particle volatility, size distribution and PAH/alkyl-PAH profiles during toluene pyrolysis in a flow reactor
Published in Aerosol Science and Technology, 2022
Pengcheng Zhao, Tie Li, Ang Li, Yongzhi Ma, Mingming Fang, Xinling Li
Concentrations of alkyl-PAHs were 1–2 orders of magnitude less than the corresponding parent PAHs, suggesting that methyl radicals make a limited contribution to the growth of PAHs. The results can also be explained by the fact that primary pyrolysis pathways of toluene are hydrogen and methyl radical scission reactions (Klippenstein, Harding, and Georgievskii 2007). Once hydrogen and methyl radicals are formed, they will attack unreacted toluene, which accelerates the consumption of toluene (Zhang et al. 2010). Additionally, methyl-Nph may also be attacked by methyl radicals until a more stable structure such as Acy, a PAH with high abundance, is formed, even though other intermediate species can also contribute to the formation of Acy (Jin et al. 2021). As the temperature increased above 1250 °C, alkyl-PAHs almost disappeared regardless of residence times, which can be ascribed to the rapid substitution reaction of the methyl group by a hydrogen atom. Prior studies (Colket and Seery 1994; Gleason et al. 2021) have observed the decrease of methyl-Nph concentration above 1227 °C, and attributed it to cracking of methyl-PAH or rapid dimerization. Therefore, methyl radical addition to benzenoid PAHs may contribute little to the formation of alkyl-PAHs as substitution and dealkylation reaction are more significant above 1250 °C.
Influence of multifluorophenyloxy terminus on the mesomorphism of the alkoxy and alkyl cyanobiphenyl compounds in search of new ambient nematic liquid crystals and mixtures
Published in Liquid Crystals, 2021
Kunlun Wang, Mohammad S. Rahman, Tibor Szilvási, Jake I. Gold, Nanqi Bao, Huaizhe Yu, Nicholas L. Abbott, Manos Mavrikakis, Robert J. Twieg
In the case of 27–28 incorporating ether connectivity to the biphenyl ring and alkyl connectivity to the halogenated terminating ring were synthesised to compare the mesogenic properties with the alternative mono ether analogues 19–24. Compound 27 was synthesised by following reaction path in Scheme 4, wherein Mitsunobu reaction was performed to obtain the alkyne precursor followed by Sonogashira reaction with pentafluoroiodobenzene and hydrogenation. The analogous compound 28 was synthesised using a different synthetic approach as shown in Scheme 4. In this case, the hydroxy tail-terminated alkylpentafluorophenyl precursor was prepared by Sonogashira reaction and then hydrogenation. Later, the target compound 28 was prepared by Mitsunobu reaction with 4-hydroxy-4ʹ-cyanobiphenyl. In addition, the known dialkoxycyanobiphenyl 26 [10] in Table 3 is synthesised according to the reaction Scheme 2 to better understand its mesogenic properties and to compare with mono alkoxycyanobiphenyl analogue 28.