Reactions of NH

Elementary collision-induced processes of NH radicals can be of a chemical nature or of a physical nature (change of quantum state (excitation or quenching)). Only the product analysis gives a definite answer for the interaction pathway. Many of the investigations concerning elementary processes of NH were done in the gas phase, which is significantly different from the kinetic situation in condensed media. Therefore, the two situations are described in separate sections. 

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In the direct process, NF is produced by the reaction of NH and F2 in the presence of molten ammonium acid fluoride (27). The process uses a specially designed reactor (28). Because H2 is not generated in this process, the ha2ards associated with the reactions between NF and H2 are elirninated. 

Monobromamine. In organic solvents monobromamine [14519-10-9] is dark violet. It is formed rapidly and quantitatively by reaction of NH and Br2 in organic or aqueous media = 7.4 x 10 M at 25°C. The solutions are relatively unstable, decomposing as follows ... 

Fig. 9.4 Time course of the chemiluminescence reaction of (NH SO t -activated panal at pH values 4.5, 5.0, 5.5, and 6.0, in 3 ml of 10 mM acetate buffer in the presence of lOmg of CTAB, 20 pi of 0.1 M FeSC>4, and 20 pi of 10% H2O2 and at pH 8.0, in 3 ml of 50 mM Tris-HCl buffer containing 0.18 mM EDTA, 10 mg of CTAB, lOmg of NaHCC>3, 20pi of 0.1 M FeSC>4, and 20pi of 10% H2O2. All at 25°C. From Shimomura, 1989, with permission from the American Society for Photobiology.

Dimerization. One of the principal reactions of NH is dimerization to diimide (N2H2). Azobenzenes are often obtained in reactions where aryl nitrenes are... 

We have investigated the reaction of NH phosphinous amides with diphenyl-cyclopropanone. The products were unequivocally identified as the corresponding p-phosphinyl carboxamides 27 resulting from the hydrolysis of a presumed heterocyclic intermediate (Scheme 28) These results await publication. 

Reactions of higher orders than two are less common, though some third-order reactions are encountered. Proceeding in a similar way for reaction of nh order,... 

EXAMPLE 20.1. Write an equilibrium equation for the reaction of NH, and H 0. and label each of the conjugate acids and bases. 

Figure 22.19 Biotinylated liposomes may be formed using biotinylated PE. Reaction of NHS-LC-biotin with PE results in amide bond linkages and a long spacer arm terminating in a biotin group.

Reaction of NHS-LC-Biotin with Diamine-Modified DNA Probes... 

Singlet NH inserts into the CH bonds of hydrocarbons, much like singlet methylene (see Chapter 7 in this volume). Triplet NH abstracts hydrogen atoms from hydrocarbons to form aminyl (NHp radicals and alkyl radicals in the same manner as triplet methylene, in spite of the fact that the reactions of CH2 are exothermic, whereas some reactions of NH are endothermic, depending on the alkane Absolute rate constants for many of these processes have been measured in the gas phase. However, the gas-phase chemistry of methylene is much more developed than that of imidogen. ... 

Formation of a white cloud from the reaction of NH and HCI. The cloud is NH CI salt. 

Rates of reaction of NH(/> Z + ) with CH4, C2H4, and CjHa are two orders of magnitude slower than the corresponding rates of NH( A) as shown in Table V-iOC. 

The reactions of NH formed in the flash photolysis ofNH, have been studied by several workers. Mantei and Bair (660) have obtained the rate constant for the reaction... 

In the laboratory, hvdra/iiie can be prepared by convening one-half of a given amount of NFL into chloramine. NILCI. hy sodium hy pochlorite solution in the presence ot a colloid and heating. The remaining one-hulf of the NHi reacts with chloramine to form hydrazine. The product is then cooled to 0 C and HySOj added in amount to react with the hydrazine to form hydrazine sulfate. NTh.SOj. insoluble solid. Hydra/ine hcmisulfate. tN Hsi SOj. is soluble in H 0. It can also be made by the reaction of NH i and hydroxy lamiiteO sulfonic acid. 

Just as for the reaction of Nh with CC14 [29], no ion formation could be detected as a result of luminescence quenching. This has been explained by subsequent fast recombination reactions of the ions formed. According to the estimation of ref. 34 based on the values for the added quencher concentrations, the distances of electron transfer from the triplet excited state of a TMPD molecule to PA and from HMTI to PMA are equal to about 25 A. 

Scheme 3.2 The labeling reaction of amino-modified RNA (R2) with NHS-activated dye (Rl) and a competing side reaction of NHS hydrolysis.

Anionic Complexes. The preparation of these compounds is indicated in Table III. The product of the reaction of (NH COsCle] with chlorine gas at 400°C will dissolve in dilute hydrochloric acid from this... 

Dealumination and silicon-enrichment reaction of (NH SiF6 (AHFS) with zeolites Besides the hydrothermal method for preparation of ultra-stable Y zeolite (USY), Breck and Skeels[23] in 1983 invented a new secondary synthesis method for silicon-enriched zeolites. This method uses an ammonium hexafluorosilicate solution to remove the aluminum atoms from the framework structure of Y zeolite to the solution, and to insert silicon atoms back into the Al-removal vacancies in the framework so as to form a more or less perfect Y zeolite with a high Si/Al ratio. In comparison with the USY prepared by the hydrothermal method, the framework silicon-enriched Y zeolite obtained through the current technique possesses fewer framework hydroxyl vacancies, and the resulting zeolite has an ideal crystal lattice, and hence higher structural stability. Meanwhile, there... 

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