Ammonium bromide salts

The internal modes can be seen in Fig. 5.2(b) above 1200 cm. This region of the spectrum is very rich and again there are too many features to be explained by the two fundamentals alone. The external mean square displacement value is so big that most of the intensity arising from the internal vibrations is actually found in the phonon wings ( 2.6.5). Here the full wing is operative and includes translational and librational contributions. Indeed few of the sharp features present in this part of the spectrum are due to zero phonon transitions of the fundamentals. This is but a slightly more severe case of the analysis that will be covered in detail for benzene and we end our analysis of the pure ammonium bromide salt here. 

A few months later, Maruoka et al. reported an interesting base-free enantiose-lective PTC version of the reaction [261c]. Using very low loadings (1 mol%) of the chiral ammonium bromide salt 169 in a 10/1 mixture of H O and toluene as solvent, these authors have achieved high enantioselectivities in the Michael addition of... 

The first step can be realized both by reaction of AA with HBr or with NMI (the reaction of NMI with HBr leads to the stable methyl ammonium bromide salt which doesn t react with AA), followed by elimination of water using microwave technical. The exchange of anion using ammonium salt is rapid (10 min in acetone). The ammonium bromide resulting from the counter-anion exchange is insoluble in acetone and, as a consequence, is easily removed from reaction mixture by a simple filtration. 

Thomas TJ, Ponnusamy KE, Chang NM, Gahnote K, Minteer SD. Effects of annealing on mixture-cast membranes of Nafion and quaternary ammonium bromide salts. J Membr Sci 2003 213 55-66. 

One prevalent strategy for this involves tire use of a phase transfer agent, such as tetraoctyl ammonium bromide, to bring gold and silver salts into an organic phase [12, and. Reduction of tire metal salts... 

Mono-, di-, and trivalent bromides and iodides may be made by methods similar to the chlorides. The lower valence salts also disproportionate in water. Indium trifluoride [7783-52-0] InF., is sparingly soluble in water. It forms an ammonium double salt, SNH F TnF. [15273-84-4] which decomposes on heating to indium nitride [25617-98-5] InN. 

Sonawane et al. [90] investigated the affect of ultrasound and nanoclay for the adsorption of phenol. Three types of nanoclay tetrabutyl ammonium chloride (TBAC), N-acetyl-N,N,N trimethyl ammonium bromide (CTAB) and hexadecyl trimethyl ammonium chloride (HDTMA), modified under sonication, were synthesized which showed healthier adsorption of phenol within only 10 min in waste water. The interlamellar spacing of all the three clay increased due to incorporation of long chain quaternary salts under cavitational effect. 

An appreciable amount of a slimy solid collects on the walls of the bomb. It appears to consist of ammonium bromide together with a small amount of iron salts dissolved from the walls of the bomb by the action of the ammonia. The amount of product recovered by careful working of this material is less than 2 g. 

Hydrobromide. A complex process takes place in the first step of weight loss of melamine hydrobromide (250-400 C) as shown by the DTG curve of Figure 6. The products evolved in this step were shown to be a mixture of melamine hydrobromide (IR) and ammonium bromide (IR and X-ray). The IR spectrum of the residue (55% at 400 0 which is compared with the original salt in Figure 7, is identical with that of reference melam hydrobromide. Furthermore, the IR of the residue... 

The reaction of sodium azide with N-aryl chloroimines, obtained from benzanilides and thionyl chloride, to form 1,5-disubstituted tetrazoles is catalysed by tetra-n-butyl-ammonium bromide (Scheme 5.26, Table 5.40) [18] in variable yields, but generally <85%. 5-Butyl-2,3-diphenyltetrazolium salts have also been used as catalysts [18, 19]. 1,5-Disubstituted tetrazoles are also obtained from a one-pot sequential reaction of carbodimides with sodium azide and an aroyl chloride in the presence of tetra-n-butylammonium chloride [20]. 5-Chlorotetrazoles are obtained from the catalysed reaction of aryldichloroisocyanides with sodium azide (Scheme 5.26) [21],... 

The dehydrohalogenation of 1- or 2-haloalkanes, in particular of l-bromo-2-phenylethane, has been studied in considerable detail [1-9]. Less active haloalkanes react only in the presence of specific quaternary ammonium salts and frequently require stoichiometric amounts of the catalyst, particularly when Triton B is used [ 1, 2]. Elimination follows zero order kinetics [7] and can take place in the absence of base, for example, styrene, equivalent in concentration to that of the added catalyst, is obtained when 1-bromo-2-phenylethane is heated at 100°C with tetra-n-butyl-ammonium bromide [8], The reaction is reversible and 1-bromo-l-phenylethane is detected at 145°C [8]. From this evidence it is postulated that the elimination follows a reverse transfer mechanism (see Chapter 1) [5]. The liquidrliquid two-phase p-elimination from 1-bromo-2-phenylethanes is low yielding and extremely slow, compared with the PEG-catalysed reaction [4]. In contrast, solid potassium hydroxide and tetra-n-butylammonium bromide in f-butanol effects a 73% conversion in 24 hours or, in the absence of a solvent, over 4 hours [3] extended reaction times lead to polymerization of the resulting styrene. 

Note Examples are potassium salts of unbranched alkanoic acids, lecithin, certain polyisocyanates, cellulose derivatives with side-chains, such as (2-hydroxypropyl)cellulose, and cyanobiphenyl derivatives of alkyl(triethyl)ammonium bromide. 

Cetyltrimethyl ammonium bromide (CTAB) dodecyltrimethyl ammonium bromide (DTAB) tetradecyltrimethyl ammonium bromide (TTAB) trioctyl-methyl ammonium chloride (TOMAC) N-benzyl-N-dodecyl-hf-bis(2-hy-droxy ethyl) ammonium chloride (BDBAC) cetyl pyridinimn chloride (CPC) quaternary ammonium salt with carbon atoms of R ranging from 8-10 (CHj Rj N+ CL) (Aliquat 336)... 

In general it is found that salts of strong acids yield more stable ammines than do those of weak acids, and in most cases the stability of the amminc is parallel with the stability of the corresponding ammonium salt. For instance, both hexammino-nickel iodide, [N NH JIj, and ammonium iodide decompose at higher temperatures than hexammino-nickel bromide, [Ni(NH3)0]Br2, and ammonium bromide. The more stable ammines are also the least soluble in water. 

From the same solution, therefore, ammonium nitrate is capable of forming the diaquo-p,-amino-ol salt, whereas ammonium bromide and ammonium iodide yield respectively the bromide and the iodide of the p,-amino-diol salt.2... 

Dichloro - tetrammino - platinic Bromide, [Pt(NH3)4Cl2]Br2, is produced by treating the nitrate of the series with ammonium bromide, when the salt is precipitated as a yellow crystalline powder. Silver nitrate replaces two atoms of bromine by two nitrate radicles. 

Figure 8.10a is an example of some data in which the effect of added salt is more than a competitive ion-binding phenomenon. The reaction involved is the decarboxylation of 6-nitrobenzisoxazole-3-carboxylate, catalyzed by hexadecyl trimethyl ammonium bromide micelles ... 

The solubility of ammonium bromide in water has been measured by J. M. Eder,6 and by A. Smith and H. E. Eastlack—the values of the latter are, in grms. of salt per 100 grms. of water ... 

---