Ammonium bromide application

Experiments pertaining to a new system for the application of bromine to flame retardant polypropylene and foamed polystyrene are described. The FR compound, ammonium bromide, is formed in the amorphous regions of the polymer phase by the interaction of bromine sorbed on the polymer and ammonia, sorbed subsequently. Gaseous nitrogen which is also produced, expands and brings about the rearrangement of the chains to produce a porous structure. The ammonium bromide produced is finely divided and imparts FR properties to the polymer. 

When a surfactant is injected into the liquid beneath an insoluble monolayer, surfactant molecules may adsorb at the surface, penetrating between the monolayer molecules. However it is difficult to determine the extent of this penetration. In principle, equilibrium penetration is described by the Gibbs equation, but the practical application of this equation is complicated by the need to evaluate the dependence of the activity of monolayer substance on surface pressure. There have been several approaches to this problem. In this paper, previously published surface pressure-area Isotherms for cholesterol monolayers on solutions of hexadecy1-trimethyl-ammonium bromide have been analysed by three different methods and the results compared. For this system there is no significant difference between the adsorption calculated by the equation of Pethica and that from the procedure of Alexander and Barnes, but analysis by the method of Motomura, et al. gives results which differ considerably. These differences indicate that an independent experimental measurement of the adsorption should be capable of discriminating between the Motomura method and the other two. 

Aluminum bromide AlBr3 is used as a catalyst and parallels AICI3 in this role. Strontium and magnesium bromides are used to a limited extent m phamiacentical applications. Ammonium bromide is nsed as a flame retardant in some paper and textile applications potassium bromide is used in photography. Phosphorus tribromidc PBr3 and silicon tetrabromide SiBi4 are nsed as intermediates and catalysts, notably in the production of phosphite esters. 

Generation of HOBr can be effected by the activation of sodium bromide or (by-product) ammonium bromide, by rapid intimate mixing with chlorine gas or, more usually, sodium hypochlorite. This method is widely used in general industrial cooling systems (as well as other applications, such as brewery pasteurizers, where it provides an alternative to BCDMH chemistry). 

Cotton Ammonium phosphates are the most effective FRs for cotton as first identified by Gay-Lussac in 1821 and still widely used. All phosphates on heating release phosphoric acid, which catalyses dehydration reactions of cellulose to yield char at the expense of volatiles formation reactions.50 However, ammonium phosphates like mono- or diammonium phosphates are water soluble, hence applicable as nondurable treatments only. Ammonium bromide can be used in combination with ammonium phosphates to provide some vapor-phase FR action. Other examples include borax and boric acid, ammonium sulfamate, and sulfates. These nondurable finishes are useful for disposable fabrics, insulation, wall boards, theatrical scenery, packaging material, paper, etc. Ammonium polyphosphates (APPs) are used in combination with urea to provide semidurable finishes and by curing at 160°C, when some phosphorylation can occur. Semidurable finishes are very useful for materials that may not need frequent washings, e.g., mattresses, drapes, upholstery, carpets, etc. Some commercial examples of semidurable finishes include Flammentin FMB (Thor Specialities), Pyrovatim PBS (Ciba, now marketed by Huntsman), etc.26... 

Wool Wool, though not as flammable as cotton, still needs flame retardation for specific applications, e.g., carpets, upholstered furniture in transport, etc. Ammonium phosphates and polyphosphate, boric acid-borax, and ammonium bromide can be successfully used in nondurable FR finishes for wool. Various commercial products have been reviewed by Horrocks.3 The most successful durable treatment for wool is Zirpro, developed by Benisek, which involves exhaustion of negatively charged complexes of zirconium or titanium onto positively charged wool fibers under acidic conditions at 60°C. The treatment can be applied to wool at any processing stage from loose fiber to fabric using exhaustion techniques. 

Ooi T, Kameda M, Maruoka K (2003) Design of N-spiro C2-symmetric chiral quaternary ammonium bromides as novel chiral phase-transfer catalysts synthesis and application to practical asymmetric synthesis of a-amino acids. J Am Chem Soc 125 5139-5151... 

The application of a new combined gravimetric and volumetric method to the determination of the ratio of silver to ammonium chloride and also to ammonium bromide furnished Stas 5 in 1882 with another... 

The vast majority of miniemulsion polymerizations reported in the literature have been stabilized with anionic surfactants, probably because of the widespread application of anionic surfactants in macroemulsion polymerization, and due to their compatibility with neutral or anionic (acid) monomers and anionic initiators. However, Landfester and coworkers [70, 71] have used the cationic surfactants cetyltrimethyl ammonium bromide (CTAB) and cetyltri-methyl ammonium tartrate for the production of styrene miniemulsions. They report that these surfactants produce similar particle sizes to anionic surfactants used at the same levels. Bradley and Grieser [72] report the use of dodecyltrimethyl ammonium chloride for the miniemulsion polymerization of MMA and BA. 

However, this method is not always possible and in those cases some approximation must be used. A common and successful approach is to assume that the value of changes little across the region of a transition and its observed wing intensity. The integrated intensity across this region is then taken to be the total intensity, as corrected for wing effects. In the case of ammonium bromide the application of Eq. (5.10) is reasonable and Weff Hv The intensities are integrated over 310 to 380... 

Let us now discuss some applications of microemulsions in catalytic processes. It has been shown in [298] that the use of microemulsions instead of organic solvents for electrochemical reactions is advantageous from both economical and ecological reasons. The electrode/fluid interface in microemulsions probably consists of a dynamic layer of surfactant molecules packed more loosely on the electrode than in aqueous solutions. Microemulsions provide good yields of carbon-carbon addition products in reactions catalysed by cobalt complexes when preparing vitamin B 2. Excellent stereo-selective control in microemulsions made with the cationic surfactant cetyl trimethyl ammonium bromide was demonstrated for the catalytic cyclisation of 2-(4-bromobutyl)-2-cycIohexene-l-one to 1-decalone. Electrochemical synthesis may be a viable future approach to environmentally friendly chemical methods. 

The application of a 11-ferrocenylundecyl-ammonium bromide/hexa-decylammonium bromide surfactant mixture as structure-directing agent resulted in a lamellar mesostructured silica film, which showed electronic conductivity due to electron transport in the ferrocenyl chains. Lyotropic lithium triflate-silicate liquid crystals have been utilized as supramolecular templates in the synthesis of ionically conducting nanocomposite films. ... 

Halides of some hydrocarbons, containing multiple carbon-carbon bonds as well as other functionalities, have also been phosphorylated via the Michaelis-Becker procedure [361-363]. The modem tendency in the application of the Michaelis-Becker synthesis is to carry out a one-pot synthesis without the necessity of intermediate isolation of the dialkyl phosphite salt. It has been shown that the Michaelis-Becker reaction can be carried out in the presence of potassium carbonate and a phase-transfer catalyst (tetrabutyl ammonium bromide— TBAB) [364]. 

In this research, cetyl trimethyl ammonium bromide (CTAB), as an arrtimicrobial ent is applied on polyester, polypropylene and viscose non-woven fabrics alone and in combination with a Fluorochemical (FC 1112). The antimicrobial, water and blood repellency of the treated samples were investigated. To reveal the antimicrobial properties of the treated samples, the zone of inhibition and reduction of bacteria were measured with S. aureus, E. coli and P. aeroginosa. The results showed a good antimicrobial property on different concentration of CTAB solutions (1%, 2%, 4% and 8%). Application of CTAB with concentration of (0.5%, 1% and 2%) on polyester, polypropylene and viscose nonwoven fabrics indicated a reasonable antimicrobial effect Co-application of CTAB with fluorochemical on different samples also showed a good antimicrobial, water and blood repellency properties. 

Applications related to vanadium determination and micellar media can also be found. Different oxidation states of vanadium have been determined at pH 5 using gallic acid in a cationic micellar solution of cetyltrimethyl ammonium bromide (CTAB). 

Formulations of ammoniiun phosphates and ammonium bromide, sometimes with wetting and softening agents, are sold for use on cellulosic-S5mthetic fiber blends. A large-volume use in the United States for ammonium phosphate is in forest fire control, usually by aerial application and often combined with ammonium sulfate. 

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