Hydrogen cyclohexene

Y Okada, N Ohta. Amino acids and peptides. VII. Synthesis of methionine-enkephalin using transfer hydrogenation, (cyclohexene) Chem Pharm Bull (Jpn) 30, 581, 1982. 

Nitrogen ligands have played a minor role in homogeneous hydrogenation compared with those of phosphorus, but some such catalysts are known. The 1,10-phenanthroline complex (37) has been shown to hydrogenate cyclohexene.140... 

A highly dispersed Pd on ZrC>2 catalyst was prepared by activating an amorphous Pd35Zr65 alloy by oxidation at 543 K. Almost complete conversion in the hydrogenation of cyclohexene (523 K, hydrogen/cyclohexene = 9) was achieved with the catalyst prepared by a 10-h oxidation207. The conversion with the as-received sample was only... 

The major products of the radiolysis of liquid cyclohexane are hydrogen, cyclohexene and bicyclohexyl with G-values of 5.55, 3.27 and 1.95 respectively . The reactions involved are given in the general mechanism outlined by Dyne , viz. 

Assume that you are in a laboratory carrying out the catalytic hydrogenation ( cyclohexene to cyclohexane. How could you use a mass spectrometer to deter when the reaction is finished ... 

The yields of hydrogen, cyclohexene, and bicyclohexyl decrease markedly on adding C02 or SF6 to cyclohexane (56, 57), and these decreases can be qualitatively accounted for in this way. The energy taken up by XY in Reaction 7 may result in formation of products derived from the solute. 

Table I. Radiolytic Yields of Hydrogen, Cyclohexene, and Bicyclohexyl from Cyclohexane...

Pure Cyclohexane. The major products from the radiolysis of cyclohexane are hydrogen, cyclohexene, and bicyclohexyl. Dewhurst (4) proposed that these could be formed by the production of hydrogen atoms and cyclohexyl radicals, followed by abstraction by hydrogen atoms and recombination and disproportionation of the cyclohexyl radicals. Dyne and Jenkinson (5) showed that part of the hydrogen yield is unimolecu-larly formed. It was suggested that excited cyclohexane molecules give... 

Figure 4. Hydrogen, cyclohexene, bicyclohexyl yields from molar solutions of benzene in cyclohexane...

Cyclohexane and Nitrous Oxide. The effect of nitrous oxide on the yields of hydrogen, cyclohexene, and bicyclohexyl at conventional dose rates has been studied by Sagert and Blair (12), and their results are included in Figures 7 and 8. These authors explain their results by the replacement of Reaction lb, (C6Hi2+ + e C6Hi2 ), by Reactions 10 to 12. 

Cyclohexane and SF . Sulfur hexafluoride reacts rapidly with electrons, and its effect on the hydrogen, cyclohexene, and bicyclohexyl yields has been explained (12) by the replacement of Reaction lb by Reactions 14 and 15. 

We can get a quantitative idea of benzene s stability from the heats of hydrogenation. Cyclohexene, an isolated alkene, has AHtyiinv — — 118 kJ/mol (-28.2 kcal/mol), and 1,3-cyclohexadiene, a conjugated diene, has =... 

RhCl3-3H20] in presence of (31) was shown to hydrogenate cyclohexene in 1 1 mixtures of... 

The yields of hydrogen, cyclohexene and bicyclohexyl have been taken from Reference 39, those of the other products from References 18 and 40. 

Hydrogen, cyclohexene, and bicyclohexyl are the major products from radiolyses of cyclohexane. Scission of a CH bond is a major reaction mode. At high doses, polymeric species are formed upon secondary reaction of cyclohexyl radicals with cyclohexene molecules. 

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