Hydrocarbons destructive hydrogenation

Several methods, involving solvent extraction or destructive hydrogenation, can accomplish the removal of aromatic hydrocarbons from naphtha. By destructive hydrodegation methods, aromatic hydrocarbon rings are first ruptured and then saturated with hydrogen, which converts aromatic hydrocarbons into the odorless, straight-chain paraffinic hydrocarbons required in aliphatic solvents. 

Studies of hydrogenation, including destructive hydrogenation (Nemtsov, Prokopets, Dyakova), reported in the 1930 s, may have been utilized by now for industrial processes. A. V. Frost has been conducting research on the kinetics of catalytic reactions and on catalytic cracking. Frost and M. D. Tilicheev are co-editors of a series of publications on physical constants of hydrocarbons which may be used as a source of information on the synthesis of individual hydrocarbons. Other Russian groups have contributed (N. D. Zelinskii, A. D. Petrov) to this field. Some of this work involves catalytic reactions however, in this review mere mention of it may suffice. 

For industrial hydrogenation of vegetable and animal oils in Russia a Raney type nickel was prepared by Bag and co-workers (64). Preparation of detergents from hydrogenated fats has been reported (11). Reviews of these so-called skeleton catalysts were published by Russian investigators, for instance, by Lel chuk and co-workers (197). These catalysts have also been discussed with reference to hydrocarbon synthesis from water gas (148). Lel chuk (197) states that Raney nickel is more drastic for water gas synthesis than are the skeleton nickel catalysts prepared by Bag, and that Bag s copper-nickel skeleton catalysts approach nickel in their activity. Destructive hydrogenation under mild conditions was said to be possible with Bag s skeleton catalyst as described by Lel chuk. 

It must be remembered that an important step in the destructive hydrogenation process is a reduction in the molecular weight of the hydrocarbons. This involves rupture of a C—C bond. 

Although his governmental duties occupied much of Ipatieff s time, he still was able to continue his scientific work and to study the destructive hydrogenation of hydrocarbons. 

Any polymer with unsaturated hydrocarbon groups, either in the main chain or as side groups, can be hydrogenated. Early research on the hydrogenation of elastomers focused on destructive hydrogenation with consequent... 

In the case of cracking of fuel oil by hydrogen under pressure (destructive hydrogenation), the commercial products discharged from the plant are petrol, kerosene, methane, butane and higher hydrocarbons, while the unreacted raw material and the hydrogen are returned as recycle material to the plant for cracking the ethane and propane formed are passed on to be... 

Continued addition of 02 beyond one-half the stoichiometric value with the hydrocarbons present encourages a net destruction of the hydrocarbon radicals. For the temperature range 1200-1300 K, production of the hydrocarbon radicals via hydrogen abstraction by 02 is rapid, even assuming an activation energy of 520kJ/mol, and more than adequate to provide sufficient radicals for NO reduction in the stay time range of 125 ms. 

In the late 1980s, however, the discovery of a noble metal catalyst that could tolerate and destroy halogenated hydrocarbons such as methyl bromide in a fixed-bed system was reported (52,53). The products of the reaction were water, carbon dioxide, hydrogen bromide, and bromine. Generally, a scmbber would be needed to prevent downstream equipment corrosion. However, if the focus of the control is the VOCs and the CO rather than the methyl bromide, a modified catalyst formulation can be used that is able to tolerate the methyl bromide, but not destroy it. In this case the methyl bromide passes through the bed unaffected, and designing the system to avoid downstream effects is not necessary. Destruction efficiencies of hydrocarbons and CO of better than 95% have been reported, and methyl bromide destructions between 0 and 85% (52). 

Chlorinated hydrocarbons (CHCs) are widely used in industry but bring both environmental and health risks 5,120 catalytic oxidation is a low cost method for their destruction. The most active catalysts are the platinum group metals supported on alumina, but high temperature is needed to obtain a satisfactory rate and to overcome chloride poisoning,121 but hydrogen chloride attacks the alumina support, so the use of other supports that... 

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