Unsaturated hydrocarbon facilitated

The presence of electronegative groups in unsaturated hydrocarbons facilitates their reduction. For example, the presence of a nitrile group adajcent to a single olefinic bond or benzenoid ring enables those systems to accept an electron within the potential range available in the usual solvents. In DMF, benzonitrile forms a radical aniou. Phthalo-nitrile behaves similarly but can be reduced further with the elimination of one cyanide ion... 

Nickel-catalyzed cyclizations, couplings, and cycloadditions involving three reactive components have been an active area of research for the past decade [39,40]. Central to these reactions is the involvement of a low-valent nickel capable of facilitating oxidative coupling of an unsaturated hydrocarbon (such as an alkyne, allene, or alkene) and a carbonyl substrate (such as an aldehyde or ketone). The use of NHCs as ligands has been evaluated for couplings of aldehydes. Such reactions typically afford O-protected allylic alcohols in good yields. 

Besides facilitating such displacement reactions THF and other solvents aid the reaction of metals with organic compounds. The preparation of unsaturated hydrocarbon-metal adducts is immeasurably more rapid in such ethers. Thus, although lithium and biphenyl react very slowly in diethyl ether to form a 1 1 adduct (several days), the same reaction in THF proceeds momentarily (compare Section II.G). 

Strained square planar structure of the PSiP-linkage would facilitate structural change to a trigonal bipyramidal geometry, which might allow coordination of CO2 for facile carboxylation. (iii) The pincer structure would enable a catalytic cycle based on Pd(II) without liberation of Pd(0), which causes side reactions through oxidative cyclization of unsaturated hydrocarbons. 

The investigation into thiyl-catalyzed isomerization of olefins eventually resulted in the measurement of relative rate coefficients for several CH3S + olefin reactions. These early relative rate studies relied on the interpretation of complex chemical systems to arrive at rate coefficients for the elementary reactions involving CH3S attack on the olefin double bond. More recently, the characterization of the CH3S laser induced fluorescence (LIF) spectrum [90,91] has led to direct measurements of rate coefficients for methyl thiyl radical reactions with unsaturated hydrocarbons. Reported relative rate coefficients are tabulated along with the recent direct measurements of Balia et al. [92] (see Table 6). This has been done to allow for observation of any reactivity trends that may be present and to facilitate qualitative discussion of proposed CH3S+olefin reaction mechanisms. 

Facilitated Transport of Unsaturated Hydrocarbons in Perfluorosulfonic Acid (Nafion) Membranes... 

Due to their extensive use in the polymer industry and as solvents, there is a continuing need for better separation processes for alkenes and other unsaturated organic compoimds from alkanes. Perfluorosulfonic acid (PFSA) membranes, such as Nafion (1), that have been ion-exchanged with silver(I) ion exhibit large transport selectivities for many unsaturated hydrocarbons with respect to saturates with similar physical properties. These selectivities are the result of reversible complexation reactions between the unsaturated molecules and Ag+ (2-4), which results in facilitated transport through the membranes (5). 

Medium-chain fatty acids are saturated fatty acids because of the relatively shorter hydrocarbon chain, which does not facilitate unsaturation. The safety of medium-chain triacylglycerol (MCTs) in dietary oil has been debated, and associated effects on cholesterol metabolism remain unclear. Although some studies have shown that... 

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