Tetralin mechanisms

We propose, therefore, that the operative mechanisms of coal conversion in both Tetralin-like media and our strongly basic systems may be the same, involving hydride donation by the H-donor... 

H2 + CH4, D2, P2 + Tetralin, GO + H2O were selected and reduction was conducted by varying the reaction time. Each isolated fraction was subjected to ultimate analysis, H-NMR, C-13 NMR, molecular weight measurement and the structural parameters were calculated. The results of the study of these structural parameters in the course of the reactions were evaluated and the reaction mechanisms thereof are discussed below. 

Mechanisms of the formation of the decal ins in the recovered solvent were based on their isotopic contents. The cis-Decalin-die had a greater protium content than the recovered Tetralin-di2-This suggested that hydrogen transfer from the coal to the tetralin is involved in the formation of cis-Decalin. 

To summarize the exchange and donation mechanisms of Tetralin, pathway 1 in Figure 2 is the predominant pathway of exchange and donation as determined by preferential incorporation of protium into the a-position of Tetralin. Tetralin-di2 loses a deuterium atom from the a-position, and a protium atom is incorporated into the a-position. This equilibrium is the exchange pathway. Continued loss of deuterium from the a-Tetralinyl radical eventually leads to naphthalene, and this reaction is the donation pathway. 

The isotopic composition of the Decal ins in the spent solvents is indicative of the mechanisms of their formation. A total of 6 hydrogen atoms are added to the Tetralin to form Decal in. In E10, during the course of the experiment, the average protium concentration in the Tetralin increased from 2.3 to 21.3 atom % 1H. The protium content of 34 atom % 1H in the cis-Decalin was greater than the protium content in the Tetralin. Likewise in El9, the protium content in the Tetralin increased from 1.0 to 12.3 atom% H, while the cis contained 18.8 atom % 1H. This increase of pro-... 

Pt(II)(8-quinolinolate), Tb(III)(TTFA)3(o-phen) with TTFA = thenoyltrifluoroacetonate and o-phen = 1.10— phenanthroline, Tb(III)(TTFA) , and Eu(III)(TFFA)3 (o-phen). An eel of Re(o-phen)(CO)3C1 occured during the electrolysis of tetralin hydroperoxide in the presence of the rhenium compound. The mechanism of these electrochemical reactions is discussed. 

Partial reduction of polyarenes has been reported. Use of boron trifluoride hydrate (BF3 OH2) as the acid in conjunction with triethylsilane causes the reduction of certain activated aromatic systems 217,262 Thus, treatment of anthracene with a 4-6 molar excess of BE3 OH2 and a 30% molar excess of triethylsilane gives 9,10-dihydroanthracene in 89% yield after 1 hour at room temperature (Eq. 120). Naphthacene gives the analogously reduced product in 88% yield under the same conditions. These conditions also result in the formation of tetralin from 1-hydroxynaphthalene (52%, 4 hours), 2-hydroxy naphthalene (37%, 7 hours), 1-methoxynaphthalene (37%, 10 hours), 2-methoxynaphthalene (26%, 10 hours), and 1-naphthalenethiol (13%, 6 hours). Naphthalene, phenanthrene, 1-methylnaphthalene, 2-naphthalenethiol, phenol, anisole, toluene, and benzene all resist reduction under these conditions.217 Use of deuterated triethylsilane to reduce 1-methoxynaphthalene gives tetralin-l,l,3-yielding information on the mechanism of these reductions.262 2-Mercaptonaphthalenes are reduced to 2,3,4,5-tetrahydronaphthalenes in poor to modest yields.217 263... 

Alkylaromatic hydrocarbons, such as tetralin, ethylbenzene, and cumene, are oxidized in a solution of acetic acid in the presence of cobalt acetate by a different mechanism. In these... 

During the chain oxidation of hydrocarbons, sulfides and disulfides terminate chains by reacting with peroxyl radicals [40,42,44], which, as opposed to phenols, are weak inhibitors (see Table 17.6). The mechanism and stoichiometry of the termination reaction by sulfides remain yet unclear. Since sulfenic acid is an efficient scavenger of free radicals, the oxidation of tetralin in the presence of dialkylsulfoxide occurs only if the initiation rate v > vimin is proportional to the concentration of sulfoxide [5], so that the rate of oxidation is... 

Labelling experiments provided the evidence that the Fe1- and Co1-mediated losses of H2 and 2H2 from tetralin are extremely specific. Both reactions follow a clear syn- 1,2-elimination involving C(i)/C(2) and C(3)/C(4), respectively. In the course of the multistep reaction the metal ions do not move from one side of the rr-surface to the other. The kinetic isotope effect associated with the loss of the first H2 molecule, k( 2)/k(Y)2) = 3.4 0.2, is larger than the KIE, WFLj/ATHD) = 1.5 0.2, for the elimination of the second H2 molecule. A mechanism of interaction of the metal ion with the hydrocarbon n-surface, ending with arene-M+ complex 246 formation in the final step of the reaction, outlined in equation 100, has been proposed241 to rationalize the tandem MS studies of the unimolecular single and double dehydrogenation by Fe+ and Co+ complexes of tetraline and its isotopomers 247-251. 

The conversion of tetralin to a-tetralone may be achieved under aqueous biphasic conditions in the presence of 02, using NiCl2 as a catalyst, as shown in Scheme 9.3 [7], It is necessary to use tetraethylene pentamine (TEPA) as a surface-active ligand, as well as an emulsifier, dodecyl sodium sulfate. Some alcohol and naphthol by-products were also observed, and a radical chain mechanism has been proposed for this reaction. 

Stewart, J., Supercritical Pyrolysis of the Endothermic Fuels Methylcyclohexane, Decalin, and Tetralin, Ph.D. Thesis, Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 1999. 

Direct Liquefaction Kinetics Hydrogenation of coal in a slurry is a complex process, the mechanism of which is not fully understood. It is generaly believed that coal first decomposes in the solvent to form free raclicals which are then stabilized by extraction of hydrogen from hydroaromatic solvent molecules, such as tetralin. If the solvent does not possess sufficient hydrogen transfer capability, the free radicals can recombine (undergo retrograde reactions) to form heavy, nonliquid molecules. A greatly simplified model of the liquefaction process is shown below. 

The kinetics of the zinc diisopropyl dithiophosphate-in-hibited oxidation of cumene at 60°C. and Tetralin at 70°C. have been investigated. The results cannot be accounted for solely in terms of chain-breaking inhibition by a simple electrow-transfer mechanism. No complete explanation of the Tetralin kinetics has been found, but the cumene kinetics can be explained in terms of additional reactions involving radical-initiated oxidation of the zinc salt and a chain-transfer step. Proposed mechanisms by which zinc dialkyl dithiophosphates act as peroxide-decomposing antioxidants are discussed. 

The present paper reports the results of a kinetic study of the inhibition of the azobisisobutyronitrile-initiated autoxidation of cumene at 60 °C. and of Tetralin at 70 °C. by zinc diisopropyl dithiophosphate, undertaken to test the validity of the chain-breaking inhibition mechanism proposed above. In addition, the effectiveness of several metal dialkyl dithiophosphates as antioxidants in the autoxidation of squalane... 

From these results, it is clear that neither Equation A nor B represents the kinetics of the zinc diisopropyl dithiophosphate-inhibited autoxi-dation of cumene or Tetralin. This does not immediately indicate that the mechanism in Scheme 1 is wrong since it is highly idealized and takes no account of possible side reactions. A similar situation occurs in the inhibition of hydrocarbon autoxidation by phenols (AH), for which a basic mechanism similar to that in Scheme 1 is accepted. Termination occurs via Reactions 7 and 8 instead of Reactions 5 and 6. 

Vacuum distillation of the benzyl derivative 77 gave a mixture of equal amounts of four products (Scheme 19) stilbene was also formed, again suggesting a radical mechanism.7 A dilute solution in boiling tetralin, however, gave only 76 (60%) and 78 (18%).13 In the case of 59 both a methyl and a phenyl group were observed to migrate.13... 

The Jones reagent851 and < rt-BuOOH in the presence of chromium(VI) complexes852,853 were found to be particularly useful in the oxidation of tetralins and indans. Oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) occurs with an exceptional mechanism.854 In contrast with the radical processes observed in other oxidations DDQ generates a carbocation by hydride abstraction that is trapped by water to form an alcohol ... 

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