Methane, addition

The dephlegmator process recovers a substantially higher purity C2+ hydrocarbon product with 50—75% lower methane content than the conventional partial condensation process. The C2+ product from the cryogenic separation process can be compressed and further separated in a de-ethanizer column to provide a high purity C3+ (LPG) product and a mixed ethylene—ethane product with 10—15% methane. Additional refrigeration for the deethanization process can be provided by a package Freon, propane or propylene refrigeration system. 

We came up with the idea of using a dummy ligand, as shown in Scheme 1.23 [34]. Reaction of dimethylzinc with our chiral modifier (amino-alcohol) 46 provided the methylzinc complex 62, which was subsequently reacted with 1 equiv of MeOH, to form chiral zinc alkoxide 63, generating a total of 2 moles of methane. Addition of lithium acetylide to 63 would generate an ate complex 64. The ate complex 64 should exist in equilibrium with the monomeric zincate 65 and the dimer 66. However, we expected that the monomer ate complex 64 and the mono-... 

Biochemical waste transformation occurred at low waste concentrations, resulting in the production of methane. Additional microbial degradation of the waste resulted in the reduction of sulfates to sulfides and ferric ions to ferrous ions. 

Horita and Berndt (1999) studied the abiogenic formation of methane under conditions present at hydrothermal vents. Solutions of bicarbonate (HCO3 ) were subjected to temperatures of 470-670 K and a pressure of 40 MPa. Under these conditions, CO2 was reduced only very slowly to methane. Addition of a nickel-iron alloy, which corresponds closely to the minerals in the Earth s crust, led to a clear increase in the reaction rate of methane synthesis. The following reaction is assumed to occur ... 

On treatment of glutaraldehyde with 2-hydroxy-3-nitropropionic acid, only 2-nitrocyclohexane-l,3-diol could be isolated in 10% yield, indicating that, under the conditions used, a retro-aldol degradation takes place with liberation of nitromethane. However, when using methyl 2-methoxy-3-nitropropionate, which cannot undergo a retro-nitro-methane addition", products (101) and (102) are obtained in yields of 7 and 13% respectively... 

Figure 3.1 (a) H NMR spectra of the reaction of with methane (addition at room temp., heating at 7 = 150°C for 720min) (i) starting 1 before and after CH4 addition,... 

Fluorotris(trimethylsilyl)methane addition reactions. Synthesis of... 

In the dimeric system c s,cis-[Pt2Me4(p-dmpm)2] (dmpm=bis(dimethylphosphino) methane), addition of iodomethane takes place sequentially at each metal center (the dppm analogue does not react with Mel) ... 

In the Canadian context there need not be a restriction on biomass conversion processes to be self-sufficient and therefore be required to sacrifice carbon to drive the processes, Natural gas and hydro/nuclear electricity are likely to be available on a large scale through to the early decades of the next century. One or all of the following options have been discussed in the context of biomass conversion and in the specific case of methane additions to alter hydrogen to carbon monoxide ratios in syn gas work is presently under way to combine oxygen blown wood gasification with the reforming of natural gas, (5),... 

Initial experiments performed at the INL compared different catalysts, fluids, and operating conditions to determine the effect of SCF on solid acid catalyst alkylation (5). Three sets of studies were performed a catalyst comparison using six different catalysts (i.e., two zeolites, two sulfated metal oxides, and two Nafion catalysts) with methane as a cosolvent an exploration of the effect of varying methane addition on alkylation using a USY zeolite catalyst and a study of the effect of seven cosolvents (i.e., three hydrocarbons, two fluorocarbons, carbon dioxide, and sulfur hexafluoride) at L, ML, NC-L, and SCF conditions on the USY catalyst performance. 

Methylcobalamin also participates as a substrate for an enzymatic reaction in the formation of methane in certain methanogenic bacteria. In this reaction, which can be considered as a model for the second half-reaction of methionine synthetase, the cobalt-bound methyl group is transferred to 2-mercaptoethanesulfonic acid (coenzyme M) [39], the 5-methyl sulfide of which is subsequently reduced to yield methane. Additionally, methylcobalamin participates in the rather obscure process of acetate synthesis in certain bacteria in which it can be shown that the cobalt-bound methyl group becomes the acetate methyl carbon. The details of the involvement of methylcobalamin in this process are, however, unknown. 

The activation of methane in the presence of ethylene effects methane addition to the olefin with the formation of propane. This reaction is catalyzed by the system Ti(OBu)4 + AlEt3 2 ... 

Assuming steric effects are not important, only the bond strengths change, so these are in the order Me—Me < M-Ph < M-H < M—SiR3, favoring silane addition and disfavoring methane addition. 

We can compare the stabilizing effects of substituents on radicals by comparing their effect on the strengths of, e.g., the CH bonds in methane. Addition of a vinyl or a carbonyl substituent to methane decreases the bond strength of the CH bond by approximately 13 kcal/mole. The effect is virtually independent of whether the substituent is of the or -t- type. 

Hill, S. J., Ford, M. J., and Ebdon, L. (1992) Investigations into the application of methane addition to the nebulizer gas in inductively coupled plasma mass-spectrometry for the removal of polyatomic interferences. J. Anal. At. Spectrom., 1,1152. 

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