Deuterated methane

In the late 1990s, the kinetics of H/D exchange between methane, deuter-ated FAU and MFI zeolites was studied by Schools et in the tem-... 

Decomposition. Acetaldehyde decomposes at temperatures above 400°C, forming principally methane and carbon monoxide [630-08-0]. The activation energy of the pyrolysis reaction is 97.7 kj/mol (408.8 kcal/mol) (27). There have been many investigations of the photolytic and radical-induced decomposition of acetaldehyde and deuterated acetaldehyde (28—30). 

Photolysis of Cp2TiAr2 in benzene solution yields titanocene and a variety of aryl products derived both intra- and intermolecularly (293—297). Dimethyl titan ocene photolyzed in hydrocarbons yields methane, but the hydrogen is derived from the other methyl group and from the cyclopentadienyl rings, as demonstrated by deuteration. Photolysis in the presence of diphenylacetylene yields the dimeric titanocycle (28) and a titanomethylation product [65090-11-1]. 

Bloom M., Bridges F., Hardy W. N. Nuclear spin relaxation in gaseous methane and its deuterated modifications, Can. J. Phys. 45, 3533-54 (1967). 

The occurrence of proton transfer reactions between Z)3+ ions and CHa, C2H, and NDZ, between methanium ions and NH, C2HG, CzD , and partially deuterated methanes, and between ammonium ions and ND has been demonstrated in irradiated mixtures of D2 and various reactants near 1 atm. pressure. The methanium ion-methane sequence proceeds without thermal activation between —78° and 25°C. The rate constants for the methanium ion-methane and ammonium ion-ammonia proton transfer reactions are 3.3 X 10 11 cc./molecule-sec. and 1.8 X 70 10 cc./molecule-sec., respectively, assuming equal neutralization rate constants for methanium and ammonium ions (7.6 X 10 4 cc./molecule-sec.). The methanium ion-methane and ammonium ion-ammonia sequences exhibit chain character. Ethanium ions do not undergo proton transfer with ethane. Propanium ions appear to dissociate even at total pressures near 1 atm. 

Such is not the case, and furthermore, the presence of NHS does not alter product ratios in favor of the more highly deuterated species as it does in the methane systems. The additional observation that C2D6 is untouched in TD/D2 C2H6/C2D6 mixtures (Table III, System III) makes the evidence against ethanium ion-ethane proton transfer conclusive. 

Scheme 12.18 (Deuterated) methane formation during immobilization of CpjAn(CH3)2 orCp An(CD3)2 on (deuterated) 7-AI2O3.950 [An =Th (67)/U (86)] and Y-Al203 75 [An = U (85)] can be used to distinguish three...

Wang, X. Schultz, A. Halpem, Y. (2002). Kinetics of methane hydrate formation from polycrystalline deuterated ice. J. Phys. Chem. B, 106 (32), 7304-7309. 

The chief discrepancy between the experimental results of Chanmugan and Burton and of Bell and Kistiakowsky (see Secs. IV-A and B) is that the latter workers found evidence for the presence of methyl in the reaction of methylene with hydrogen and with methane (or their deuterated isomers), whereas the results of Chanmugan and Burton were more consistent with the direct addition mechanism, at least at low temperatures. 

The importance of hyperconjugation in anionic fluorinated species has been questioned, 3,74 with the proposal that the effects of fluorination can be rationalized by involving polarization effects alone. A study of the relative rates of the deuteration of tris(trifluoromethyl)methane (1), l//-undecafluorobicyclo[2.2.1]heptane (2), and l//-tridecafluorobicyclo[2.2.2]octane (3) clearly illustrates that deuteration occurs much more rapidly with tris(trifluoromethyl)melhane... 

In another recent study of CO reduction using organometallic compounds of the early transition elements, Caulton et al. report that CH4 is evolved when toluene solutions of (C5H5)2Ti(CO)2 are heated at 150°C under H2 or H2 -l- CO atmospheres (55). When deuterium is used, the observed product is CD4, although some deuteration of the cyclopentadienyl rings is noted. Caulton does not report the percent yield of methane, but does state that the reaction is not catalytic. One of the most novel aspects of this investigation is the isolation of a blue Tig cluster that is inert to further reaction... 

Table 11.1. Observed resonant transfers from Na to methane and deuterated methane.0...

---