Reaction of ethane

The relative rates of reaction of ethane toluene and ethylbenzene with bromine atoms have been measured The most reactive hydrocarbon undergoes hydrogen atom abstraction a million times faster than does the least reactive one Arrange these hydrocarbons in order of decreasing reactivity... 

Ethyl 2,3,4-tri-O-acetyl-l-thio-a-L-rhamnopyranoside was synthesized by applying the reported method based on the BF3-Et20-catalyzed reaction of ethane... 

Suitable dialdehydes can also undergo intramolecular hydride transfer, as in the Cannizzaro reaction of ethan- 1,2-dial (55, glyoxal ) — hydroxyethanoate ( glycollate, 56) anion,... 

Figure 2. Variations of products as a function of the thermal desorption program following the reaction of ethane with 0 on MgO at 25°C. (BD indicates butadiene)(17).

Figure 3. Infrared spectra following the reaction of ethane with OJ (a) MgO background (b) after the reaction at 25°C (c) after thermal treatment under vacuum at 150°C ...

The effect of pH on the periodate oxidation of seven anilines has been investigated. " The kinetics of periodate oxidation of aromatic amines have been studied. " - " Periodate oxidation of oxalic acid is catalysed by Mn(II). " The reaction of ethane-1,2-diol with periodate has been investigated under a variety of conditions and the results compared with those of earlier work and analogous studies on pinacol. " The 104 ion is the primary reactant, with H5IO6 as a secondary reactant the reverse is true for pinacol. The complex observed in previous work is shown not to be an intermediate, but rather to deactivate the reactants. 

Fig. 26. Geometries of the two transition states for zeolite-catalyzed cracking reactions of ethane obtained from a density functional study on a zeolite cluster model. The distances are in angstroms and angles in degrees. (Reprinted with permission from Blaszkowski et al. (134). Copyright 1996 American Chemical Society.)...

A comparison of C—C and C—H bond reactivities in protolytic reactions indicated that under the conditions of alkylation C—H cleavage is much more pronounced (in the reaction of ethane, the relative ratio of C—C C—H cleavages is 9 1 in the absence of benzene and 1 10 in the presence of benzene). This indicates that overall alkylation can also involve the attack of protonated benzene (benzenium ion) on the C—H bond of the alkane [Eq. (5.48)] or interaction of benzene with the five-coordinate alkonium ion prior to its cleavage to the trivalent cation ... 

Even methane, the least reactive alkane, was shown to undergo carboxylation under superacidic conditions.115,176 The formation of carboxylated products (acetic acid and methyl acetate) from methane was first observed by Hogeveen and coworkers by trapping methyl cation formed in SbF5 (60°C, 50 atm CO pressure) followed by quenching with H20 or MeOH. The intermediate methylcarboxonium ion (CH3CO+) and CH3CH2CO+ formed in a similar reaction of ethane were identified by NMR spectroscopy.176,177... 

Activation Energies and Rate Constants of Some Gas-Phase Reactions of Ethane, Ethene, Propane, and Propene (Derived from Ref. 7)... 

It is interesting to note that the catalysts that show good selectivities at the higher temperatures generally do not contain easily reducible metal ions, such as V, Mo, or Sb. Many of the catalysts for the lower-temperatures operation, on the other hand, contain these reducible cations. In a study using a Li-Mg oxide, it was established that gas-phase ethyl radicals could be generated by reaction of ethane with the surface at about 600°C (17). These radicals could be trapped by matrix isolation and identified by electron spin resonance spectroscopy. 

The substantial difference in the heats of reaction of ethane, ethene, and ethyne with bromine is reflected in a very important practical consideration in handling ethyne (acetylene), namely its thermodynamic stability relative to solid carbon and hydrogen gas. Unlike ethane, both ethene and ethyne can be shown from bond energies to be unstable with respect to formation of solid carbon and gaseous hydrogen ... 

The products of aldol addition are /3-hydroxy aldehydes (ald-ols) or /3-hydroxy ketones (ket-ols). A typical example is the reaction of ethanal with base and, if the conditions are reasonably mild, the product is 3-hydroxybutanal ... 

Exercise 17-16 When the aldol reaction of ethanal is carried on in D20 containing OD , using moderate concentrations of undeuterated ethanal, the product formed in the early stages of the reaction contains no deuterium bound to carbon. Assuming the mechanism discussed in this section to be correct, what can you conclude as to which step in the reaction is the slow step What then would be the kinetic equation for the reaction What would you expect to happen to the kinetics and the nature of the product formed in D20 at very low concentrations of ethanal ... 

The pulsed electron beam MS technique was also used by Hiraoka and Kebarle842 to study the C4H + cations. In the ion-molecule reaction of ethane and the ethyl cation, two species were observed and identified as the 2-//-n-butoniu m cation 469 and the 2-C-w-butonium cation 470. C—C protonated ion 470 formed first rearranges to C—H protonated ion 469 (energy barrier = 9.6 kcal mol-1) and then dissociation to sec-C4H9+ + H2 takes place. 

Initial distributions of products from reactions of ethane and higher alkanes in excess D2 show that step (c) in Scheme 1 is reversible. Thus, interconversion of monoadsorbed and aj3-diadsorbed species can be very rapid especially on Pd and Rh before desorption of alkane. This interconversion is now referred to as the a(3 process. 

Often, it is desirable to conduct an aldol condensation in which the nucleophile and the electrophile are derived from different compounds. In general, such mixed aldol condensations, involving two different aldehydes, result in the formation of several products and for this reason are not useful. For example, the reaction of ethanal and propanal results in the formation of four products because there are two possible enolate nucleophiles and two carbonyl electrophiles ... 

Calculations are presented here for model molecules which resemble ethane (or ethyl radical) and butane (or butyl radical). The models are not identical with the real molecules, since our principal purpose is to vary certain energetic, structural, and frequency parameters in order to display their effects on the reaction rate and its characteristics. Thus, the results have a more general connotation than the special reactions of ethane, ethyl, butane, and butyl but, at the same time, certain cases correlate quite directly with the latter, although such connections have not been optimized. 

The kinetics of alkane hydrogenolysis, that is, the dependence of rate on reactant concentration, have been the subject of numerous studies, and much effort has been devoted to devising rate expressions based on the Langmuir-Hinshelwood formalism to interpret them. Reactions of ethane, propane, and n-butane with H2 on EUROPT-3 and -4 have been carefully studied, with the surfaces in either as clean a state as possible, or deliberately carbided [21, 22] kinetic measurements at different temperature permitted adsorption heats and true activation energies to be obtained. There were two surprises (but like all surprises they were obvious afterwards) ... 

Write the formula of the compound that is formed by the reaction of ethane with nitric acid at high temperature ... 

Once established the appropriate level of calculation, a systematic study was conducted for the dehydrogenation reaction of ethane, propane and isobutane, using the B3LYP functional along the 6-3IG and 6-31IG basis sets and both the 3T and 5T clusters to... 

Table 6. Relevant parameters for the transition states of the dehydrogenation reactions of ethane, propane and isobutane with clusters T3 and T5.

The macroscopic mass balance model by Tsotsis et al. [1992], when applied to the reaction of ethane dehydrogenation, compares well with experimental data and both show higher conversions than the corresponding equilibrium values based on either tube-or shell-side conditions (pressure and temperature). This is clearly a result of the equilibrium displacement due to the permselective membrane. The conversion, as expected, increases with increasing temperature. 

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