Alkanes and Alkyl Aromatics

At higher temperatures, C—H and C—C bonds may be similarly broken. Thus, zeolite catalysts may be used for (i) alkylation of aromatic hydrocarbons (cf. the Friedel-Crafts reactions with AICI3 as the Lewis acid catalyst), (ii) cracking of hydrocarbons (i.e., loss of H2), and (Hi) isomerization of alkenes, alkanes, and alkyl aromatics. 

A number of ILs are hydrophobic, yet they readily dissolve many organic molecules—with the exception of alkanes and alkylated aromatic compounds (e.g., toluene). Among such ILs we find [bmim][PFg], which forms triphasic mixtures with alkanes and water. This multiphasic behavior has decisive implications for clean synthesis. For example, transition-metal catalysts can be exclusively dissolved in the ionic liquid, thus allowing products and by-products to be separated from the ionic liquid by solvent extraction with either water or an organic solvent. This is advantageous when using expensive metal catalysts, as it enables both the ionic liquid and the catalyst to be recycled and reused. Alternatively, some volatile products can be separated from the IL by distillation, as it has negligible vapor pressure. 

The occurrence of HMWHCs in crude oils has typically been determined by simulated distillation but the poor chromatographic resolution associated with this approach has been a limiting factor in understanding the complexity of the HMWHC fraction (Trestianu et al. 1985 Thomson Rynaski 1992 Neer Deo 1995 Durand et al. 1998). Routine analyses of waxy crude oils by HTGC have revealed that HMWHCs are composed of complex mixtures of alkyl-cycloalkanes, methylbranched alkanes, and alkyl-aromatic hydrocarbons, and may represent a significant fraction of the whole oil (Hsieh Philp 2001). 

Often the equilibrium position of a reversible process is such that the conversion to product is low at reasonable holding times (i.e., flow rates and reactor volumes). For example, the dehydrogenation of saturated alkanes and alkyl aromatics to produce alkenes and aryl-alkenes and hydrogen is a very important case in point ... 

Alkanes and alkyl aromatic hydrocarbons can be oxidized when heated at rather high (usually above 1(X) °C) temperatures under oxygen. A long induction period can be reduced or eliminated if a donor of free radicals is present. The formation of oxygen-containing products from hydrocarbons and molecular oxygen is always thermodynamically allowed due to the high exothermicity of oxidation reactions. However, this same fact makes these processes usually unselective. The main problem is to prevent various parallel and consecutive oxidation reactions to produce numerous byproducts. Destmction of the carbon... 

In the last two decades, hundreds of papers reported the use of NHPI for promoting the homogeneous selective oxidation of a wide range of organic substrates (including alcohols, ketones, ethers, amines, amides, silanes, alkynes, alkenes, alkanes, and alkyl aromatics) and the one-pot free-radical synthesis of complex molecules, involving molecular oxygen, directly or indirectly [4]. 

Tables S.1-S.4 list some important chemical, physical, and chromatographic properties as well as general manufiicturing specifications and safety parameters for the alkanes and alkyl aromatic solvents [84-92]. Figure S.l shows the chemical structures for the solvents listed in Tables 5.1-5.4.

---