Methylamine, adsorption

Carman A, Zhang L, Liswood JL, Casey SM (2003) Methylamine Adsorption on and Desorption from Si(100), J. Phys. Chem. B 107 5491-5502... 

The presence of methylamine on quartz (lOl 1 stabilized the surface more as compared with those in the presence of water and methanoic acid (Table 3.4). The adsorption energy for an amine molecule was more negative than for water and methanoic acid (Table 3.5), indicating that in an equilibrium condition methylamine will adsorb preferentially on this surface by displacing water and methanoic acid molecules. Methylamine adsorption did not induce any noticeable surface reconstruction. Nitrogen of amine oriented itself at the bump distance (2.52 A with 70% of the sum of covalent radii) from the three-coordinated surface silicon, and the methyl group of the amine molecule was located away from the surface (Figure 3.10a). 

FIGURE 3.17 (a) Side view of methylamine adsorption on wollastonite 100 surface, (b) Perspective view... 

SBA-15 samples with diameters from 5 to 10 nm have been prepared by tuning the temperature of the first step of the synthesis [5], MCM-41 has been prepared in the presence of hexadecyl trimethyl ammonium by using methylamine as pH-controlling agent [6], The pore size from N2 adsorption at 77 K has been evaluated by the Broekhoff and de Boer method, shown to correctly evaluate the pore size of ordered mesoporous silicas [7]. 

The effects of chemisorption on the two spectral doublets further elucidate the nature of Fe2+ in the zeolite framework. Ammonia, which is small enough to enter both the main channels and the side pockets of the zeolite, is expected to affect both spectral doublets, as experimentally observed. Of the molecules methylamine, dimethylamine, trimethylamine, and piperidine, only the first has any effect on the Mdssbauer spectrum after room temperature adsorption (resulting in decreased spectral area for both doublets). At 340 K, however, dimethylamine adsorption resulted in a spectral area de-... 

Furan itself can be used as the starting material for the synthesis of 1-methylpyrrole <2002MI179>. 7-AI2O3 was found to be an effective catalyst for the dehydration reaction between furan and methylamine to afford 1-methylpyrrole. A yield of 57.6% was achieved under the experimental conditions of a reaction temperature of 400 °C, a methylamine/ furan molar ratio of 1.5, and the molar flow rate of furan approximately 3-3.5 mmol/h. Furan was adsorbed onto Bronsted acid sites on the catalyst, while the methylamine was adsorbed onto Lewis acid sites. With this heterogeneous catalyst, the rate determining step of the mechanism was suggested to be the adsorption of furan on the Bronsted acid sites to form a ring-opened species, which is followed by the insertion of the adsorbed methylamine to form secondary amine intermediates. Further dehydration at the Lewis acid sites would yield 1-methylpyrrole. 

Pong B-K, Lee J-Y, Trout BL (2005) First principles computational study for understanding the interactions between ssDNA and gold nanoparticles adsorption of methylamine on gold nanoparticulate surfaces. Langmuir 21 11599... 

MIC may be released to the environment as a result of its manufacture and use as a chemical intermediate. If MIC is released to soil, it will be expected to rapidly hydrolyze if the soil is moist, based upon the rapid hydrolysis observed in aqueous solution. If released to water, it will be expected to rapidly hydrolyze with half-lives of 20 and 9 min at 15°C and 25°C, respectively, calculated from measured overall hydrolysis rate constants. The products of hydrolysis may include N-carboxymethylamine, methylamine, carbon dioxide, and N,N -dimethylurea. Since it rapidly hydrolyzes, bioconcentration, volatilization, and adsorption to sediment and suspended solids are not expected to be significant processes. No data were located concerning biodegradation, but MIC will probably abiotically hydrolyze significantly faster than it will biodegrade. If released to the atmosphere, it will be expected to exist almost entirely in the vapor phase based upon its vapor pressure. It will be susceptible to photooxidation via vapor phase reaction with photochemically produced hydroxyl radicals. Hydrolysis of MIC in moist air may be significant based upon its rapid hydrolysis in aqueous solution. 

Perez-Mendoza, M., Domingo-Garcia, M., and Lopez-Garzon, FJ. (2000). Adsorption of methylamines on carbon materials at zero surface coverage. Langmuir, 16, 7012-18. 

These considerations are strikingly demonstrated by the volcano-shaped pattern of variation of catalytic activity as shown schematically in Figure 7.3. While the heat of adsorption is steadily decreasing from left to right, the catalytic reaction rates peak at the group VIII metals in the periodic table. Figure 7.3 shows the pattern of variation of catalytic reaction rates across the series of transition metals Re, Os, Ir, Pt, and Au for the hydrogenolysis of the C—C bond in ethane, the C —N bond in methylamine, and the C —Cl bond in methyl chloride. 

Metal cations Metal cation reduction Metal cations in MeAPO synthesis Metal corrosion prevention Metallocene, supported catalyst 24-0-05 Metallosilicates, microporous Methanol adsorption Methanol amination Methanol conversion Methanol dehydrogenation Methanol formation Methanol in alkylation 15-0-03 25-0-03 Methanol to hydrocarbons Methanol, reagent Methanol, steam reforming Methylamine in MFI synthesis N-Methylation, aniline Methylation, 4-methylbiphenyl Methylation, toluene, model 4-methylbiphenyl, methylation Methylcyclohexane cracking Methylcyclopentane hydroconversion Methylene silanes... 

Kaesche and Hackerman (13) have investigated the inhibition of several aliphatic and aromatic amines on pure iron corroding in IN hydrochloric acid. These authors observed in thirteen out of fourteen cases that the inhibition was both anodic and cathodic, albeit predominantly anodic. The exception was methylamine which acted only cathodically. In the case of the corrosion inhibition on pure iron by B-naphthoquinoline in sodium sulfate/sulfuric acid solution (13). one observes a simple parallel shift of the anodic and cathodic Tafel lines towards smaller values of current density. Here the effect is almost symetrical, indicating that this inhibitor acts to the same extent upon anodic and cathodic reaction rates. Therefore, the effect of B-naphthoquinoline can be explained on the basis that its adsorption blocks a fraction 0 of the metal surface for all electrode reactions. If equation 9 describes the external polarization behavior in terms of a function of the partial current potential relationship for the anodic and cathodic reactions in the usual terms ... 

It is not always easy to find direct correlations between the heats of adsorption and the catalytic behaviour (activity and/or selectivity). Various attempts at establishing such correlations have been reported in the literature. For instance, a comparison of microcalorimetric measurements with kinetic studies performed over acidic zeolites for methylamine disproportionation reactions, methanol dehydration, and reactions of methanol and dimethylether with methylamines, suggests that acid sites are required in these reactions for the strong adsorption of ammonia and methylamines, while weak adsorption sites are required to facilitate desorption of adsorbed amine species from the acid sites [147]. 

The observed oscillations in both types of oscillators appear to be non-periodic, sometimes chaotic and noisy. This is probably due to random adsorption of amine and pheromone vapours. However, it has been reported that periodicity increases in case of methylamine and pheromones. 

Adsorption Energies (kj/mole) for Water, Methanoic Acid, and Methylamine on Quartz Surfaces... 

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