Reaction products sulfur distribution

The influence of electronegative additives on the CO hydrogenation reaction corresponds mainly to a reduction in the overall catalyst activity.131 This is shown for example in Fig. 2.42 which compares the steady-state methanation activities of Ni, Co, Fe and Ru catalysts relative to their fresh, unpoisoned activities as a function of gas phase H2S concentration. The distribution of the reaction products is also affected, leading to an increase in the relative amount of higher unsaturated hydrocarbons at the expense of methane formation.6 Model kinetic studies of the effect of sulfur on the methanation reaction on Ni(lOO)132,135 and Ru(OOl)133,134 at near atmospheric pressure attribute this behavior to the inhibition effect of sulfur to the dissociative adsorption rate of hydrogen but also to the drastic decrease in the... 

In addition to accelerating degradation rates for halogenated aliphatics, reaction with sulfur nucleophiles will have significant consequences with respect to reaction product distributions. Schwarzenbach et al. (1985) have observed the formation of thiols and dialkyl sulfides from the Sn2 reactions of primary alkyl bromides with HS (Figure 2.12). 

If total sulfur curve is simulated by using any model that considers total lumping or averaging any profile distribution without proper validation with experimental data, prediction of sulfur in products can be restricted to short range of reaction conditions, and reliable results cannot be expected. If a sulfur distribution is assumed by taking from the literature any correlation between sulfur content and boiling point, the use of experimental sulfur curve data to validate/derivate the model parameters is mandatory (Chou and Ho, 1988). 

It is noteworthy that 108 reacts in AcOH with benzenesulfenyl chloride to give a 1 1 mixture of the sulfur analogues of 138 and 140, but when the reaction is carried out in the presence of LiClC>4 a complex mixture of at least five products was detected. From this comparison the authors suggest that areneselenenylation is much less affected by the solvent than arenesulfenylation, and if the reaction profiles for the two product-forming processes are assumed to be similar, the difference in product distributions can be interpreted in terms of a more efficient bridging ability of selenium than that of sulfur. In the addition of selenenyl derivatives, the solvent-dependent product distribution has also... 

Hydrocracking, 30 48-52 behavior, thermal, 29 269 catalytic, 26 383 deethylation, 30 50 demethylation, 30 50 metallocarbene formation, 30 51-52 of f -decane, 35 332-333 primary coal liquids, 40 57 procedure, 40 66-67 product distribution, 30 49 reactions, over perovskites, 36 311 suppression by sulfur, 31 229 zeolite-supported catalysts, 39 181-188... 

Fig. 18. Product distribution from the reaction of cyclopropane with hydrogen as a function of sulfur coverage over a Ni(l 11) catalyst. Temperature = 550K. Total pressure = 100 torn Hj/cyclopropane = 100. From Ref. 4.)...

The production of ozone in power-plant plumes has been suggested to explain ozone spatial distributions in nonurban areas.Comparison of oxidation mechanisms competing for sulfur dioxide suggests that three reactions—... 

Besides the rearrangement of carbocations resulting in the formation of isomeric alkylated products, alkylation is accompanied by numerous other side reactions. Often the alkene itself undergoes isomerization prior to participating in alkylation and hence, yields unexpected isomeric alkanes. The similarity of product distributions in the alkylation of isobutane with n-butenes in the presence of either sulfuric acid or hydrogen fluoride is explained by a fast preequilibration of n-butenes. Alkyl esters (or fluorides) may be formed under conditions unfavorable for the hydride transfer between the protonated alkene and the isoalkane. 

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