Hydrocarbon elimination

The mechanism proposed involves hydrogenation of the C2 C3 double bond, formation of 2-vinylthiophenol by an E2 elimination, and hydrocarbon elimination by homolysis of the S—Caryi bond. This pathway rationalizes the primary formation of (104) observed in some HDS reactions of (102) over Co/Mo/S catalysts, as well as the kinetic evidence that the rate-determining step on real catalysts is the removal of surface sulfur.158-160... 

The reaction of diphenylmethane with dibenzylbarium in THF, or barium /-butoxide with trimethylsilyldiphe-nylmethane, Ph2CH(SiMe3), in the presence of BunLi forms barium diphenylmethanide by hydrocarbon elimination and desilylation mechanisms, respectively.304 Crystallized in the form of its 18-crown-6 ether derivative 116 (Figure 60), the complex displays direct Ba-C bonds of 3.065(3) and 3.097(3) A, and a longer contact at 3.39 A. 

As an alternative to the hydrocarbon-elimination method, salt-elimination reactions involving an organometallic halide, which can be generated in situ, and an alkali-metal pnictide have also been used (Scheme 9.15a). The elimination of a volatile triorganosilyl halide is viable in cases where the steric bulk... 

More specialized reaction types are hydrocarbon elimination (Section 4.4.4.2) and condensation of species with M—M multiple bonds121 (Section 4.4.1.10). 

A number of compounds having a direct zinc transition metal bond are known for long time, that is, zinc-bis(transition metal) such as Zn[Co(C04)]2 and transition metal zinc halides such as (CO)4Fe(ZnCl)2. However, organozinc-transition metal compounds RZn-TM are comparatively more recent. They can be prepared by hydrocarbon elimination between a diorganozinc derivative and a transition metal hydride (see Hydrides) (equation 35), but dialkyl- and diarylzinc compounds usually fail to react or react very slowly. Furthermore, when they do react they give unstable products that show a very strong tendency to disproportionate and cannot be isolated (equation 36). 

So far, dibenzyl derivatives remain the only hydrocarbon source for hydrocarbon elimination reactions, especially since... 

I went to Los Angeles to get first-hand information from the authorities and learn the conditions of the automobile exhaust problem. Low cost, easy installation on every car, no effect on performance of the engine, hydrocarbon elimination above 80%—these were the principal requirements for consideration. 

The greatly diminished thermostability of homoleptic alkyl compounds of the transition metals compared to analogous complexes of the main group elements is not a result of smaller energies of metal-carbon bonds, but is due to hydrocarbon elimination processes which take place because the transition metals possess d orbitals. - ... 

Alkyl groups may be eliminated as dimers or as disproportionation products if they contain hydrogen atoms in the P position. The P elimination process affords the metal hydride, which causes hydrocarbon elimination in the protonolysis reaction of MR ... 

Fig. 9. Polycyclic aromatic hydrocarbon elimination constants for oyster (Crasso-strea virginica) and clam Mercenaria mercenaria). Bivalves were exposed for 28 d to field-contaminated sediment and then allowed to eliminate their acquired tissue concentrations for 28 d. See Appendix for chemical abbreviations. (Data from Bender et al. 1988.)...

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