Interaction of loparite concentrate with ammonium hydrodifluoride

Results obtained in a study of the interaction between the loparite concentrate and ammonium hydrodifluoride are reported. It was found that the reactions of the main components of the concentrate with NH₄HF₂ yield complex ammonium fluorometallates. It was shown that water leaching of the fluorinated product makes it possible to transfer niobium and tantalum into solution together with fluoroammonium salts of titanium and silicon and to concentrate rare-earth elements in the insoluble residue in the form of complex salts of general formula NaLnF₄.     

Reaction of niobium pentoxide with ammonium hydrodifluoride

The reaction between Nb₂O₅ and NH₄HF₂ is studied by thermogravimetric analysis, IR spectroscopy, and crystal-optical analysis. Intermediates and their formation temperatures are determined.     

Reaction of magnesium oxide and magnesium silicates with ammonium hydrodifluoride

The reactions of magnesium oxide and magnesium silicates (forsterite and serpentines) with ammonium hydrodifluoride is studied using DTA, X-ray powder diffraction, and IR spectroscopy. The conditions for the formation of intermediate phases are determined. The structure of the silicate mineral does not significantly affect the fluorination.     

Interaction of heavy metal ions with ammonium humates

Sorption properties of ammonium humates with respect to Fe(III), Cu(II), Al(III), Ni(II), Pb(II), and Zn(II) are studied. The effect of the metal ion concentration on the ammonium humate consumption is examined and the corresponding dependences are analyzed using regression equations. The IR spectra of brown coal humic acids, ammonium humates, as well as Fe, Cu, Ni, Zn, Pb, and Al humates are presented.     

Interaction of water-insoluble quaternary ammonium salts with the hydrated silica surface

PMR spectroscopy of adsorbed molecules upon freeze-out of the liquid phase was used to study the interaction of high-molecular-weight quaternary ammonium salts differing in the structure of the hydrophilic part of the molecule and the distance between the nitrogen atoms with the hydrated aerosil surface. This approach not only yields data on the change in the hydration shell of the adsorbents upon insertion of complex organic molecules with several types of reaction sites but also permits evaluation of the efficiency of the adsorption interactions.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 32, No. 6, 376–379, November-December, 1996.     

Interaction of polysilicic acid with monolayers of substances containing quaternary ammonium groups

The action of polysilicic acid on monolayers of a quaternary ammonium salt and a phospholipid spread on substrates of various pH values was studied. The films of benzyl dimethyl hexadecyl ammonium chloride were considerably affected above pH 2. No interaction was observed, at any pH, between silicic acid and dipalmitoyl phosphatidyl serine.The results support the existence of ionic interactions between dissociated silanol groups and tetra-alkylammonium groups. The involvement of hydrogen bonds is ruled out.     

m-6-m型Gemini双季铵盐表面活性剂与DNA的相互作用

合成了5种m-6-m型Gemini双季铵盐表面活性剂,在对产物结构和表面活性进行分析的基础上,分别采用紫外分光光度法和荧光分光光度法考察了m-6-m型Gemini双季铵盐表面活性剂与DNA的相互作用.结果表明,m-6-m型Gemini表面活性剂的CMC随烷基疏水链的增长呈逐渐下降趋势.几种表面活性剂均没有使DNA的紫外吸收峰发生红移或蓝移现象,说明复合物无嵌插作用或氢键形成,表面活性剂与DNA作用后的吸光度随表面活性剂浓度的增大而增强,当表面活性剂的浓度相同时,吸光度随疏水链的增大而逐渐减弱.Gemini表面活性剂浓度增大导致荧光强度降低,表面活性剂与DNA作用时的猝灭为静态猝灭,随着疏水链长度的增长,荧光猝灭常数降低,表面活性剂与DNA之间的作用力减弱.     

Interaction of nickel hydroxocarbonate,ammonium paramolybdate,and ammonium metatungstate under mechanical activation

The interaction of nickel hydroxocarbonate, ammonium paramolybdate, and ammonium metatungstate (Ni: Mo: W = 3: 1: 1) is reported. Under mechanical activation conditions, nickel hydroxocarbonate particles undergo comminution and ammonium paramolybdate and ammonium metatungstate particles soften and aggregate. It is demonstrated by DTA, X-ray diffraction, and IR spectroscopy that heat treatment of the mechanically activated mixture at 400–450°C yields the salts NiMoO₄ and NiWO₄.     

Interaction between quaternary ammonium ions and dipeptides: positive anion allosteric effect

The binding properties of dipeptides possessing aromatic residues towards quaternary ammonium ions have been investigated by 1H-NMR spectroscopy. The intermolecular hydrogen bonding between exchangeable protons (OH and NH) of aromatic residues of dipeptides and the counter anion of ammonium ion is the primary force. After the formation of the intermolecular hydrogen bonding, two aromatic residues of dipeptides can provide pi-base cavity to interact with the quaternary ammonium moiety.     

Heterogeneous reactivity of chlorine atoms with ammonium sulfate and ammonium nitrate particles

In this laboratory study, model particles of ammonium sulfate (AS) and ammonium nitrate (AN) were exposed to chlorine atoms and uptake experiments were performed in a coated wall flow tube reactor coupled to a molecular beam mass spectrometer. The reactive surfaces were prepared by coating the inner surface of the reactor using two different methods: either by depositing size-selected particles on the halocarbon wax or by spray depositing thin films using a constant output atomizer. The observed uptake coefficients vary for (NH(4))(2)SO(4), ranging from γ(Cl)(AS)≈ 1 × 10(-3) for size-selected particles to γ(Cl)(AS)≈ 6 × 10(-2) for thin films prepared by spray. An uptake coefficient of γ(Cl)(AN)≈ 2.5 × 10(-3) of Cl˙ on size-selected NH(4)NO(3) particles was measured. A heterogeneous recombination of Cl atoms to from Cl(2) molecules was observed for the two surfaces. Furthermore, an ageing process was observed for AS particles, this phenomenon leading to the formation of new chlorine species on the solid substrate.     

Interaction between biosurfactant surfactin and cationic surfactant cetyl trimethyl ammonium bromide in mixed micelle

An anionic/cationic mixed surfactant aqueous system of surfactin and cetyl trimethyl ammonium bromide (CTAB) at different molar ratios was studied by surface tension and fluorescence methods (pH 8.0). Various parameters that included critical micelle concentration (cmc), micellar composition (X ₁), and interaction parameter (β ^m) as well as thermodynamic properties of mixed micelles were determined. The β ^m was found to be negative and the mixed system was found to have much lower cmc than pure surfactant systems. There exits synergism between anionic surfactin and cationic CTAB surfactants. The degree of participation of surfactin in the formation of mixed micelle changes with mixing ratio of the two surfactants. The results of aggregation number, fluorescence anisotropy, and viscosity indicate that more packed and larger aggregates were formed from mixed surfactants than unmixed, and the mixed system may be able to form vesicle spontaneously at high molar fraction of surfactin.     

Sintering of kaolinite with ammonium fluoride

The present work represents a study of the influence of ammonium fluoride on the thermal behaviour of kaolinite by using a derivatograph. The sintering of kaolinite with ammonium fluoride was found to be complicated. Different products of sintering are obtained, depending on the temperature and the amount of ammonium fluoride. They were identified microscopically and by using a Siemens Crystalloflex diffratometer. These include an ammonium aluminium fluoride complex, cryptohalite, aluminium fluoride, mullite, topaz and corundum. The DTA curves (using kaolinite and ammonium fluoride mixes of ratio 1:1) indicate the formation of the ammonium aluminum fluoride complex and cryptohalite at 120–280°C and the appearance of aluminium fluoride, topaz and mullite at 640°C. The intensive formation of topaz takes place at 750°C and its subsequent dissociation at 940°C with corundum formation. The very small endothermic peak at 1010°C represents the formation of mullite. In experiments using mixes of kaolinite—ammonium fluoride in the ratios 1:1 and 1:1.3 the end-product of sintering consists of corundum and mullite. When using mixes of the ratio 1:1.7, aluminium fluoride constitutes the main composition of the end-product.     

Condensation of ammonium ion with acetone

Recrystallization of ammonium anthranilate or ammonium salicylate from acetone-hexane results in conversion of the ammonium salts to diacetoneammonium salts. The reaction is general for the ammonium salts of amino- and hydroxy-substituted benzoic acids, all of which are converted at least in part to diacetoneammonium salts when treated with acetone. Under similar conditions ammonium benzoate is converted to the triacetoneammonium salt. These reactions constitute convenient laboratory procedures for the preparation of diacetoneammonium and triacetoneammonium salts, and explain the frequent incursion of diacetoneamine and triacetoneamine as artifacts when natural systems are extracted with acetone.     

Thermal decomposition of ammonium uranates precipitated from uranyl nitrate solution with ammonium hydroxide

Thermal decomposition of ammonium uranates precipitated from uranyl nitrate solutions on addition of aqueous ammonium hydroxide under various conditions has been examined by thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy and X-ray diffraction study. The TG curves of all precipitates show the weight-loss corresponding to the calculated value as UO₃·NH₃·H₂O. The DTA curves of the precipitates give the endotherms at about 130, 210 and 590 °C and the exotherms at 340–420 °C. As a result, it is found that ammonium uranates thermally decompose to amorphous UO₃ at about 400 °C, and transform to U₃O₈ via β-UO₃.     

Spectrophotometric determination of phenylhydrazine with ammonium molybdate

Summary The determination of phenyl hydrazine is done by reaction with ammonium molybdate; the pink colour procedud is extracted inton-butanol. 100–1300g of phenyl hydrazine can be determined at 510 nm. The effect of time, temperature, ammonium molybdate concentration and interferences has been studied.

---

Zusammenfassung Die Bestimmung von Phenylhydrazin erfolgt auf der Grundlage seiner Reaktion mit Ammoniummolybdat. Die rosa Färbung wird mitn-Butanol extrahiert. 0,1–1,3 mg Phenylhydrazin können bei 510 nm gemessen werden. Der Einfluß der Reaktionszeit, der Temperatur, der Reagenskonzentration sowie auftretende Störungen wurden untersucht.