Kinetics of thermal decomposition of ammonium persulfate

Kinetics of thermal decomposition of ammonium persulfate was studied by calorimetry and Raman spectroscopy. The values of activation energies of the overall reaction and its individual stages were estimated.     

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.     

Kinetic features of ammonium persulfate decomposition in aqueous medium

Russian Chemical Bulletin - Decomposition of ammonium persulfate in an aqueous medium (353–368 K) is limited by decomposition of persulfate ions with a rate constant logk 2 =...     

瓜尔胶及其衍生物的过硫酸铵氧化降解研究

通过考察90℃,0.5‰过硫酸铵对瓜尔胶、羟丙基瓜尔胶及其羧甲基羟丙基瓜尔胶不同时间的氧化降解反应,发现开始时瓜尔胶主链主要是以糖苷键断裂的降解为主,当降解到一定程度后,才出现糖链上糖环的氧化。瓜尔胶的结构对降解反应有着很大的影响,而且降解速度:羧甲基羟丙基瓜尔胶羟丙基瓜尔胶瓜尔胶。形态观测结果表明氧化降解对微观结构有一定的影响。     

Concentration and temperature controlled oxidation and cutting of single-walled carbon nanotubes by ammonium persulfate

Science China Chemistry - SWNTs were oxidized by a simple wet chemical method involving treatment in aqueous ammonium persulfate (APS) solution at a certain temperature. Fourier transform infrared...     

Kinetic studies of photoelectrocatalytic degradation of Ponceau 6R dye with ammonium persulfate

Kinetic degradation of Ponceau 6R dye using oxidation with ammonium persulfate (APS) as oxidant, and catalyzed by electro, photo, and photo-electro at pH 1.0 was investigated. Ammonium persulfate (APS) proved to be a better oxidant of dye with photoelectrocatalytic degradation (PECD). The influence of various pH of the solution on the efficiency of degradation of dye was investigated. The results were observed that the dye decolorization was enhanced using PECD at pH 2.0. The rate of degradation of dye with APS followed pseudo-first order kinetics in the dye concentration. Also, it can be seen that increasing the concentration of oxidant (APS) led to a higher rate of dye decolorization.     

Mesoporous soft solid electrolyte-based quaternary ammonium salt

Journal of Solid State Electrochemistry - A novel mesoporous soft solid electrolyte was successfully prepared from tetrabutylammonium hexafluorophosphate, propylene carbonate, and...     

Antibacterial cotton treated with N-halamine and quaternary ammonium salt

Quaternary ammonium salts and N-halamines are widely used as biocides in antimicrobial coatings, and have been extensively studied over the past two decades. In this work, 5,5-dimethyl-3-(3′-triethoxysilylpropyl)hydantoin (SPH), and 3-(trimethoxysilylpropyl) octadecyl dimethyl ammonium chloride (SPODA) were synthesized and coated onto cotton fibers using a pad-dry process (PD) and the traditional pad-dry-cure process (PDC). The coated cotton swatches were characterized by FT-IR and SEM. The quaternary ammonium salt showed a relatively lower inactivating bacteria efficacy than did the N-halamine compounds. The chlorinated swatches coated with both SPH and SPODA using the PD process could inactivate about 7 logs of the Staphylococci aureus within 5–10 min and 7 logs of Escherichia coli O157:H7 within 10–30 min, respectively. The addition of quats in N-halamine coatings improved antimicrobial activity against Gram-negative bacteria E. coli O157:H7. However, this result was not observed when the PDC process was applied in coatings because of the increasing hydrophobicity of the coated samples under high coating temperature.     

三烷基季铵盐阳离子表面活性剂的合成与性能测定

用柠檬酸、十二烷基二甲基叔胺与环氧氯丙烷反应合成了柠檬酸三酯三烷基季铵盐阳离子表面活性剂。实验结果表明,在异丙醇溶剂中,反应体系在80℃,反应时间12h,产物的收率为91.5%。用红外光谱、元素分析、高效液相色谱对其结构进行了表征,通过测定其临界胶束浓度、Krafft点及泡沫性能,对产物表面活性进行了分析。     

Interaction of datolite concentrate with ammonium hydrodifluoride

The interaction of datolite concentrate with ammonium hydrodifluoride were studied. Under heating, ammonium hydrodifluoride fluorinates datolite to form complex fluoroammonium salts of boron, silicon, and impurity metals. The activation energy and rate constants were calculated for the reaction of datolite concentrate with ammonium hydrodifluoride in the range 100–150°C. The composition of the volatiles formed upon the heating of the fluorinated concentrate was studied, the temperature parameters of the evolution of boron and silicon to the gas phase were determined, and a process for separating these elements was proposed.     

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.     

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.     

Synthesis and antimicrobial activity of a perfluoroalkyl-containing quaternary ammonium salt

A novel perfluoroalkyl-containing quaternary ammonium salt 5 was designed and synthesized. Consequently, the antimicrobial activities of compound 5 were measured with Escherichia coli 8099 as a Gram-negative strain and Staphylococcus aureus ATCC 6538 as a Gram-positive strain. Both the minimum inhibitory concentration (MIC, the lowest concentration of compound 5 that inhibits microbial growth) values of quaternary ammonium salt 5 against Escherichia coli 8099 and Staphylococcus aureus ATCC 6538 were 7.8 μg/ml.     

Molecular and crystal structures of bis-tetrazolate ammonium salt and bis-tetrazole monohydrate

The title compounds bis-tetrazolate ammonium salt (I) and bis-tetrazole monohydrate (II) are synthesized and studied by single crystal and powder X-ray diffraction, IR and elemental analyses. Compound I crystallizes in the monoclinic space group C2/m, a = 8.8862(17) Å, b = 11.2334(21) Å, c = 3.7269(7) Å, β = 99.4(6)°, V = 367.03 ų (12), Z = 2. Compound II crystallizes in the monoclinic space group P2₁/c, a = 5.1701(9) Å, b = 4.7506(8) Å, c = 15.2197(24) Å, β = 107.2(7)°, V = 357.09(10) ų, Z = 2. In the structure of I, both ammonium cation and bis-tetrazolate counter-anion are located on twofold crystallographic axes, moreover, the bis-tetrazolate anion has a mirror plane passing through the ’C1-C1a bond. In the crystal structure of (II), the bis-tetrazole molecule sits on the twofold axis (bisecting the C1-C1a bond), whereas the solvent water molecule occupies a general position. In the crystal structure of (I), the molecules are packed via N-H…N intermolecular interactions. In the crystal structure of (II), the molecules are packed via N-H…O and O-H…O intermolecular interactions. In addition, the crystal packing of both structures is further strengthened by π-π stacking interactions.     

A novel silica aerogel microspheres loaded with ammonium persulfate gel breaker for mid-deep reservoirs

Sol–gel based transparent functional coatings such as easy-to-clean coatings, anti-glare coatings, anti-reflective coatings, and anti-fingerprint coatings have been developed and commercialized for display applications. These coatings can be applied by a spray process on the glass substrates followed by a low temperature curing at 100° to 150?°C. Hydrophobic easy-to-clean coatings exhibit high water contact angles at ≥115°, with an excellent wear durability by passing 10,000 cycles using #0000 steel wool under 1?kg load. In addition, easy-to-clean coatings show a silky touch feel with a coefficient of friction of less than 0.03. Anti-glare coatings without particles have a gloss value between 50 to 100 gloss units, an adhesion of 5B, a pencil hardness ≥8?H, and no sparkling issues on touch screen displays. A combination of easy-to-clean coatings on top of anti-glare coatings significantly increases the stylus pen durability. Single-layer anti-reflective coatings show a transmittance increase of 1.5% to 2.0% by spray coating on a single side of the glass substrate, or a transmittance increase of more than 4.0% by dip-coating on a polycarbonate substrate. Anti-fingerprint coatings show less obvious fingerprints on the coated glass surface compared to those on uncoated glass surface. These coating solutions have been scaled up to 1000?kg batch in PPG’s Tianjin plant, China.

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Anti-glare coatings with irregular surface microstructures formed during a spray process have a gloss value between 50 to 100 gloss units, a pencil hardness ≥8H, and no sparkling issues on touch screen displays. Optical profiler image (with ×50.3 magnification) of the anti-glare coating surface (70 gloss units) shows irregular microstructure patterns which are random locally but uniform in large area. The light scattering on the anti-glare coating surface is caused by these irregular surface microstructures. Thus the specular reflection is significantly reduced, causing glare reduction, gloss decrease, and haze increase.

     

Synthesis and properties of new polymeric surfactant with quaternary ammonium salt

The polymeric surfactant with quaternary ammonium salt (PQ) was synthesized by cationic ring-open polymerization using boron trifluoride diethyletherate as cationic catalyst. The chemical structure and aggregation behavior of PQ were studied by ¹H NMR, surface tension, static light scattering, dynamic laser light scattering, electrical conductivity, and fluorescence measurement. The results show the surface tension (γ_cmc) and critical micelle concentration (cmc) of PQ decrease with increasing of sodium chloride concentration. The cmc and γ_cmc values of PQ measured by electrical conductivity and fluorescence measurements mainly identify with that obtained by surface tension measurements. The thermodynamic parameters (DG_m⁰ \Delta G_m^0 ,DH_m⁰ \Delta H_m^0 ,DS_m⁰ \Delta S_m^0 ) from electrical conductivity indicated that the micellization of PQ was mainly the process of entropy-driven. In addition, the results from the viscosity stability between hydrolyzed polyacrylamide (HPAM) and PQ showed that the viscosities of mixed system for HPAM and PQ are higher than the viscosity of HPAM.     

Spectrophotometric determination of aluminium with ferron and a quaternary ammonium salt

The reproducibility of the ferron method for aluminium has been greatly improved by the addition of cetyltrimethylammonium chloride (CTMAC). The improvement is attributed to reduction of the reagent blank and increased stability of Al(ferron)(3-)(3). The aluminium-ferron complex formed in the presence of CTMAC has an absorption peak at 385 nm. The interference from iron can be eliminated by application of a correction based on measurement at two wavelengths.     

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.