Ammonia interactions

In the absence of alcohol solvents, hydrogen peroxide is thought to coordinate with Ti by displacing an Si-O bond as shown in Fig. 6.11. This sets the stage for ammonia interaction to form hydroxylamine and subsequent ammoximation of ketones to oximes.20,56 57... 

Although no high resolution studies have been reported for ammonia interaction with iron surfaces, two main states of adsorption were recognized. At 80 K adsorption is entirely molecular with a characteristic N(ls) binding energy of 400 eV, but on warming the adlayer to 290 K the N(ls) intensity is mainly at 397 eV, typical of chemisorbed nitrogen adatoms with only a small contribution at 400 eV. 

The selectivity of the ammoxidation of molecules like toluene and xylene is much higher than that of the oxidation of these compounds to aldehydes. The selectivity difference is more pronounced here than in case of propene. The initial selectivities of the propene oxidation and ammoxidation are practically the same, and the selectivity difference is mainly due to the high stability of acrylonitrile compared with acrolein. For aromatic (amm)oxidation, however, the initial selectivities also differ. Apparently, ammonia interacts with the catalyst in such a way that the activity for oxidation of the aromatic nucleus is reduced. 

Methylated 1,4-dihydropyrazines (1,2,4-tri-, 1,2,4,5-tetra-, and 1,2,4,6-tetramethyl) as well as imidazolines have been isolated from the reaction of sucrose with methylamine at high temperatures (120°-260°), for prolonged reaction periods (18 hours) and in the presence of ammonium phosphate as catalyst. 1,4-Dihydropyrazines are also isolated from the reaction of sucrose and ethanolamine sucrose-ammonia interaction yields a wide range of pyrazines and imidazoles.369-372... 

Ammonia interacting with a surface, as sketched in Fig. 4.57, will form NH4 ions coordinated to the bridging oxygen atom. Most oxide surfaces behave very similarly to the MgO surfaces. An exception is the surface generated on silica. In Si02 the Si cations are tetrahedrally coordinated. This coordination can be restored on the surface when the Si02 surface becomes exposed to H2O. Silanol groups develop, as sketched in Fig. 4.58. 

Zieve, L., Lyftogt, C., Draves, K. (1983). Toxicity of a fatty acid and ammonia interactions with h poglycemia and Krebs cycle inhibition. J. Lab. Clin. Med. 101 930-9. 

It is an obvious corollary, from the discussiom given here concerning the influence of the solvent, that in a highly basic, i.e., protophilic, medium, even acids that are normally regarded as weak would be highly ionized. It is probable that in liquid ammonia interaction with a weak acid, such as acetic acid, would occur to such an extent that it would appear to be as strong as hydrochloric acid. 

Norenberg, M.D. Astrocytic-ammonia interactions in hepatic encephalopathy. Semin. Liver Dis. 1996 16 245-253... 

Frequency / Hz Figure 4. The FR spectra of the (A) isobutane and (B) ammonia interaction with parent (solid symbols) and ground (open symbols) H-ZSM-5. Spectra were recorded using about 50 mg of sample Z23 at 373 K and 133 Pa. 

D-Fructose 6-phosphate and ammonia interact to produce hexosamine when they are added to a fraction of pig-kidney protein together with catalytic amounts of A -acetyl-n-glucosamine 6-phosphate. Neither L-glutamine nor L-asparagine can replace ammonium sulfate as a nitrogen source in this system, and D-fructose 6-phosphate cannot be replaced by D-fructose, n-xylose, n-glucose, or D-ribose. The presence of N-acetyl-D-glucosamine is also essential for this reaction. 

Ammonia may be present in air in both the vapor and particulate phase as ammonia gas and as ammonium salts. While analytical methods may distinguish between these phases, most standard methods do not. Methods have been developed that determine gaseous ammonia alone or gaseous and particulate forms of ammoniacal nitrogen separately. These methods use filter packs or sampling tubes coated with a selective adsorbent (denuder tube) to separate the phases (Dimmock and Marshall 1986 Knapp et al. 1986 Rapsomanikis et al. 1988). In these methods, gaseous ammonia is trapped by an adsorbent (e.g., citric acid, oxalic acid, phosphoric acid) on a coated filter or denuder tube (Kirchner et al. 1999). In filter methods, errors may arise due to ammonia interactions occurring on the filter and volatilization of retained ammonium salt (Dimmock and Marshall 1986 Rapsomanikis et al. 1988). 

Low energy electron diffraction investigation of NH3 adsorption and decomposition has been concerned with the three densest faces of W. Most attention has been paid to W(112) and W(IOO), with some preliminary experiments on W(llO) also. Ammonia interacts strongly with W(IOO), as shown by Estrup and Anderson (301), and May et al. (205) discovered similar behavior for NH3 on W(112). In contrast, NH3 apparently does not chemisorb on W(llO), which shows inertness (205) parallel to the resistance of this plane to chemisorption of N2. 

Cyanogen chloride is a colorless, very poisonous liquid, which boils at 15.5 . It was used to a limited degree as a war-gas cyanogen bromide was also tried but did not come into general use. Cyanogen chloride polymerizes readily to cyanuric chloride, C3N3CI3, a solid which melts at 146 . Cyanogen chloride and ammonia interact and form cyanamide —... 

COCI2 + 2HOC2H5 - C0(0C2H5)2 + 2HC1 Carbonyl chloride and ammonia interact to form urea —... 

Feng, X., Irle, S., Witek, H., Morokuma, K., Vidic, R. and Borguet, E. (2005), Sensitivity of ammonia interaction with single-walled carbon nanotube bundles to the presence of defect sites and functionalities , JACS, 127, 10533-8. 

We have illustrated the model predictions by evaluating two-phase ammonia clouds released in dry and moist air. The numerical test cases are identical to those in Kukkonen et al. (1993), which presents a comparison of the model AERCLOUD and the thermodynamical submodel of the heavy cloud dispersion program DRIFT (Webber et al., 1992). DRIFT embodies the homogeneous equilibrium model, while AERCLOUD allows also for thermodynamic nonequilibrium effects. Both models will cope with ammonia interactions with moist air as well as with the simpler dry air problem. 

When ytterbium dissolved in liquid ammonia interacts with cyclopentadiene along with Cp2Yb the complex of Yb(III) containing NH3 is formed [11, 124]. A base-free product is obtained by the sublimation of the complex in vacuum ... 

The electron-ion and electron-ammonia interactions were treated using pseudopotentials. For Li we used a bare coulomb potential truncated at a radius (Rq) that yields essentially the correct spectroscopic term value for the 2s electron. The electron-solvent molecule potential consisted of electron-charge site contributions but with Rq = 1.0 A for the protons. No allowance was made for polarization or exchange contributions. Our crude potential is justified a posteriori since it yields a reasonable description of an electron in liquid ammonia. ... 

Ammonia interacts with sodium hypochlorite to produce hydrazine, which is also used to produce ADC blowing agent. 

A comparative evaluation of the van der Waals forces for molecules of same type is shown in Table 2.3. It can be seen that the van der Waals forces are important in all cases and they cannot be ignored, not even for highly polar and hydrogen bonding molecules. For example, the dispersion contribution of water is 15% of the total van der Waals forces at 0 °C and 24% at 298 K. The dispersion forces account for over 80% for water-methane and 60% for ammonia-ammonia interactions. 

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