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Surfactants are one of the materials recommended for the cleaning of movable cultural properties. These substances are widespread in other fields - medicine, cosmetics, household appliance industry, etc. Quaternary ammonium compounds are particularly prevalent due to their cleansing and disinfectant properties. Initial studies have shown that surfactants, including quaternary ammonium compounds, have a positive effect on preserved/restored cultural properties. Using relatively low concentrations of aqueous solutions of these substances, it is possible to obtain sufficiently good results to wash out from the restoration of the document or textiles dirt, acidification of the object and colour changes that cause aging and decomposition processes - hydrolysis and oxidation. [ABSTRACT FROM AUTHOR]

A new starch-based adhesive with high solid content, high binding force, and low viscosity was prepared via hydrolysis of cassava starch with α-amylase using glycerol as a plasticizer and Ammonium Zirconium Carbonate (AZC) as a crosslinker. The adhesive was applied to coated paper as a partial substitute for SBR latex. The effects of α-amylase, glycerol, AZC, and temperature on the starch adhesive and its performance in application were investigated. The prepared crosslinking cassava starch adhesive showed a significant effect when the starch slurry concentration was 50% (w/w), the dosages of glycerol and α-amylase were 15% and 0.075%, respectively, and the enzymolysis starch was crosslinked with 12% AZC at 50 °C. The modified starch improved the paper in terms of surface strength, gloss, whiteness, and smoothness when 20% SBR latex was substituted into the coating formulation. Statistical analysis indicated that the crosslinking temperature and AZC had significant effects on the performance of the paper, while glycerin and α-amylase had little effect on it. Spectral analysis of the product showed that the crosslinking reaction took place between AZC and cassava starch. The average particle size was 528.6 nm. Scanning Electron Microscope (SEM) images of the paper surface were consistent with the other measured surface properties. [ABSTRACT FROM AUTHOR]

Ammonium polyphosphate (APP)-diatomaceous earth (DE) composite prepared by in situ polymerization was modified with silane coupling agent (KH550) and was applied as filler to prepare flame-retardant paper. Fourier transfer infrared, X-ray diffraction and thermogravimetry were used to characterize the structure and properties of the fillers, and limiting oxygen index (LOI), cone calorimeter and field-emission scanning electron microscope were used to investigate the flame-retardant properties of the filled paper. Results showed that chemical bonds occurred between APP-10 % DE filler and KH550, and APP-10 % DE filler had lower water solubility and better crystallization and thermostability after it was modified with KH550. Paper filled with modified APP-10 % DE filler had higher LOI value and lower heat release rate and mass loss at the same filler loading, and its charred residue collected after cone calorimeter test was more compact and strong. Surface modification of APP-10 % DE filler with KH550 improves its flame-retardant effect on paper. [ABSTRACT FROM AUTHOR]

A straightforward photo-annealing approach was developed for building functional polymer layers on paper. Conducting polyaniline with the ability for photothermal conversion can be readily annealed by near-infrared light. The annealed polymers become both insulating and hydrophobic. Selective photo-annealing produces a functional layer with patterned conductive arrays. This material exhibits real-time response to ammonium gas. Complete photo-annealing preserves the porous structure but changes the wettability of the polyaniline-nanofiber film. [ABSTRACT FROM AUTHOR]

Abstract: The effects of the addition of ammonium magnesium phosphate (AMP) to the paper of an electrically heated cigarette (EHC) prototype on smoke composition and toxicity were quantified and the underlying mechanisms investigated. Smoke from EHC prototypes with and without AMP and from conventional cigarettes, i.e. the University of Kentucky Standard Reference Cigarette 1R4F and eight American-blend market cigarettes, was compared. Endpoints for comparison were smoke chemistry, where toxic constituents were measured, cytotoxic activity, as measured in murine fibroblasts embryo cells by the Neutral Red Uptake Assay, and genotoxic activity, as measured in bacteria by the Salmonella Reverse Mutation Assay and in murine lymphoma cells by the TK Assay. The addition of AMP to the EHC led to a reduction of toxic substances and toxicological activity of approximately 30% compared to the EHC without AMP. Compared to the conventional cigarettes, the EHC with AMP showed reductions of 75–90%. Smoke from the EHCs generated in nitrogen atmospheres supplemented with different concentrations of ammonia and oxygen was assayed for its in vitro cytotoxicity and genotoxicity. The results indicate that the ammonia released by AMP at the heating site of the EHC is responsible for the reductions in cytotoxicity and mutagenicity for the EHC with AMP compared with the EHC without AMP. Thus, while the EHC approach distinctly reduces toxic smoke constituents compared to conventional cigarettes, the use of AMP in the paper of an EHC leads to further distinct reductions. In the study presented here, in vitro assays were used as quantitative tools to investigate toxicity-related mechanisms. [Copyright &y& Elsevier]

In this paper, we present the synthesis of new selenoloquinoxaline derivatives starting from 2‐chloroquinoxaline‐3‐carbonitrile 1. The compound 1 was subjected to a reaction with selenium metal in the presence of NaBH4 as a reducing agent in ethanol, under a nitrogen atmosphere. This reaction resulted in the formation of the sodium salt of 3‐cyanoquinoxaline‐2‐selenolate, which was subsequently reacted with α‐halogenated carbonyl compounds in situ. This reaction produced a series of newly synthesized 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐substituents. Ethyl 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐carboxylate 3a was hydrolyzed by sodium hydroxide to give the corresponding sodium salt 9. This salt was then refluxed with acetic anhydride to produce oxazinone compound 10. The reaction of compound 10 with ammonium acetate afforded pyrimidoselenolo[2,3‐b]quinoxaline derivative 11. Compound 11 was then chlorinated using phosphorous oxychloride to give the corresponding chlorocompound. [ABSTRACT FROM AUTHOR]

In the present paper, investigations of CdSe loaded poly(diallyl dimethyl ammonium chloride) (PDADMAC) nanocomposites and pure PDADMAC synthesized by wet chemical technique have been carried out. Fourier transform infrared and X-ray diffraction analysis have been performed to reveal the structural details of pure polymer and polymer nanocomposite (PNC). The dielectric behavior of pure polymer and PNC has been recorded, which results in higher value of the real and imaginary part of dielectric constant for PNC, as compared with pure PDADMAC. The increase is attributed to the addition of CdSe quantum dots to the pure polymer. The contribution of ionic and electronic polarization has been observed at higher frequency. The theoretical fitting of Cole-Cole function to the experimental data of dielectric constant of PNC and pure PDADMAC results in the determination of relaxation time and conductivity of space charge carriers. The CdSe loaded polymer nanocomposite has been used as an electrolyte in the battery fabrication with configuration Al/PNC/Ag2O. The ac conductivity measurements have been carried out for both samples in a frequency window of 1 kHz-5MHz and at different temperatures varying from 298K to 523 K. Activation energy (Ea) has been determined for pure polymer as well as PNC and is found to be less for PNC, as compared with pure polymer. Further, impedance measurement at different temperatures results in two frequency ranges corresponding to ionic conduction and blocking electrode effect. The value of bulk resistance for pure polymer and PNC has been found to be 3660Ω and 442Ω, respectively, at 298K temperature. Electric modulus has been determined and is observed to support the dielectric constant data; it further reveals the deviation from Debye behavior at a higher frequency. [ABSTRACT FROM AUTHOR]

The article discusses the development of a new synthesis that increases the performance of MFI, a zeolite. Researchers have done it through reducing the thickness of the zeolite crystal, thereby decreasing the lengths of the diffusion paths. They used a surfactant containing a quaternary ammonium group at one end to direct the synthesis of MFI. They found that when the zeolite was used to transform methanol into gasoline, the catalytic longevity has greatly increased.

Abstract: In this paper, the APP-modified reconstituted tobacco sheet (RTS) was prepared by a paper-making process. Thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR) had been used to investigate the influences of APP on the thermal degradation and the formation of evolved volatile products of RTS. TG-FTIR results illustrated that the incorporation of APP into RTS could retard the thermal degradation of the major components of RTS and meanwhile lead to the formation of more thermally stable char. Moreover, the main gases released during the pyrolysis of RTS and APP-modified RTS were H2O, CO2, CO, NH3, carbonyl compounds, alcohols and alkanes. The presence of APP changed the formation of evolved volatile products of RTS obviously. The effects of APP on the combustion behavior of RTS were studied by micro-scale combustion calorimetry (MCC), cone calorimetry (CCO) and infrared thermography (IRT). Results demonstrated that the formation of combustible gases was mainly determined by the thermal decomposition stage occurred in the temperature range of 150–600°C. The incorporation of APP into RTS influenced the release of fuel gases and the char formation in the process of the thermal decomposition of RTS, and eventually retarded the flammability of RTS. In addition, it had been found that the maximum firecone temperature of untreated RTS was higher than that of APP-modified RTS. [Copyright &y& Elsevier]

Graphical abstract Highlights • Enhancement of thermophysical properties of ADP crystal is demonstrated. • It is achieved by loading shock waves on the crystal. • It enhances the applicability of a crystal in high power laser devices. • Shock waves does not alter the thermophysical properties of KDP crystal. • KDP is better crystal to be used in fast moving and vibrating devices. Abstract Ammonium Dihydrogen Phosphate (ADP) and Potassium Dihydrogen Phosphate (KDP) crystals are grown by slow evaporation method at ambient temperature. The said crystals are utilized as a test specimen and subjected to one-dimensional 'loading of shock waves' generated by rupturing a paper diaphragm with Mach number of 1.9 using supersonic low energy table-top shock tube. Thermal diffusivity of crystal is measured using Photoacoustic spectrometer (PAS) for the normal and shock loaded crystals, thermal conductivity and thermal effusivity are computed for the given volumetric specific heat capacity of the crystals. XRD characterization studies reveals that KDP crystal has better immunity to shock wave than ADP crystal. [ABSTRACT FROM AUTHOR]

This paper focuses on the analysis and synthesis of two new gemini or bis-quaternary ammonium dimethacrylate compounds (bis-QAC) with different spacer lengths (DMBB and DMBH) for the first time. These innovative quaternary ammonium-based resin monomers can be employed as effective dental adhesives, due to their antibacterial properties against the Streptococcus mutans bacteria (bacteria in dental plaque). In this research, this blend of monomers is incorporated into a commercial adhesive (1 wt% bis-QAC and 99 wt% Tetric N-Bond). The chemical structures and thermal behavior of all prepared compounds are confirmed by FTIR, 1H-NMR, 13C-NMR and TGA/DTG. Moreover, mechanical properties, degree of conversion (monomer to polymer) and cell cytotoxicity of the samples containing an antibacterial agent are compared to commercial adhesives. Finally, experimental results illustrate that the minimum inhibitory concentration of adhesives with new bis-QAC is significantly lower than samples without an antimicrobial monomer. Moreover, the mixture of gemini QAC with adhesive does not demonstrate any adverse effect on the degree of conversion and bond strength of the experimental adhesive. Furthermore, specimens of DMBH indicate a higher antibacterial characteristic, despite the reduction in the cell viability. [ABSTRACT FROM AUTHOR]

The rotational potential function of the ammonium ion in the ammonium hexachlorides and the disordered phases of NH4Cl and α-NH4HgCl3 are derived from atom–atom potentials of the Buckingham (exp-6) type. The parameters in the atom–atom potentials are determined by matching computed and observed values of the librational and tunneling frequencies of NH4Cl, (NH4)2SnCl6, and (NH4)2PdCl6. The procedure presented in this paper is particularly useful in the determination of the potential function of noncubic ammonium compounds, where there are a large number of parameters in the potential function. The volume dependence of the parameters in the potential function is easily computed when atom–atom potentials are used to derive the rotational potential function. [ABSTRACT FROM AUTHOR]

Microalgae Coelastrella sp. could remove nutrients from anaerobically digested swine wastewater (ADSW) effectively, while its responses to the stress of Cu(II) were not well understood. In this paper, nutrients removal and growth of Coelastrella sp. were investigated at the presence of Cu(II) in ADSW. Results showed ammonium nitrogen concentration in ADSW decreased with culturing duration, while increased with an increased Cu(II) concentration. Total phosphorous concentration decreased with time, while did not drop in 4 days at Cu(II) concentration ≥1.0 mg/L. Microalgal growth was inhibited at all the Cu(II) concentrations, and ceased in about 6–8 days at Cu(II) concentration ≥1.0 mg/L. With an increased Cu(II) concentration, the contents of chlorophyll a and proteins decreased, those of malondialdehyde and superoxide dismutase, and ratios of octadecanoic acid (C18:0), hexadecanoic acid (C16:0) and octadecenoic acid (C18:1) to fatty acids in Coelastrella sp. increased, while octadecatrienoic acid (C18:3) gradually disappeared. [ABSTRACT FROM AUTHOR]

Cellulose paper and cotton swabs have been tested as sampling, reaction and measurement media for quaternary ammonium compounds (QACs) using the reagent Chromo Azurol S in the presence of aluminum cations (CAS-Al). On the basis of the results obtained a new method is proposed for the analysis of QACs in water samples which only entails the successive immersion of swabs into 1 mL of the samples, 1 mL of a solution of CAS-Al for the formation of a ternary blue complex, and 1 mL of water to remove the excess of reagent. The method can be used for the visual on site detection of QACs in effluents, as well as for their quantification within the 3.62–36.2 mg/L range through the direct measurement of the reflectance diffuse of the cotton tips. The proposed approach has been validated for the identification and quantification of QACs in water, and applied to effluents generated by the dairy industry. Moreover, the proposed methodology can be also adapted to the on-site detection of residues of QACs in surfaces at sub μg/cm 2 levels. [ABSTRACT FROM AUTHOR]

Electronics systems for space application always demand higher performance, weight saving and volume diminution etc. without sacrificing their reliability. As part of this stringent requirement, a few circuit blocks which are repeatedly used in various inertial systems are being realized in Hybrid Micro Circuits (HMCs). Recently, a few batches of HMCs fabricated by a specific vendor showed low electrical isolation between the HMC package body and other functional pins at ambient temperature. However, the electrical isolation values were found to be normal at elevated temperatures. The low electrical isolation was causing leakage current between pins or package body to other pins. This makes the performance of the HMCs unpredictable during its operational period. In this paper, study and analysis conducted with respect to the low electrical isolation observed in HMCs are discussed. Root cause of the problem was analyzed by conducting methodical and systematic tests based on a formulated Ishikawa model. The major tests conducted in this analysis include external visual inspection, isolation measurements, Scanning Electron Microscopy (SEM), leak tests, Residual Gas Analysis (RGA), internal visual inspection etc. Based on the test results, root cause of the isolation problem was narrowed down to process related, which was one of the primary causes as stipulated in Ishikawa model. The real cause of the problem was the formation of ammonium hydroxide inside the HMC due to the presence of ammonia and moisture. The defective HMCs showed very large quantity of these conducting residues inside the HMCs during the RGA test. These residues emanated from the epoxy material used to attach the alumina substrate in the HMC. These faulty HMCs have not undergone vacuum baking properly before being sealed due to faulty functioning of the chamber. Hence residual gases and moisture could not be outgassed completely before sealing. Internal visual inspection of the HMCs revealed spill over of substrate attach epoxy to the Glass To Metal Seal (GTMS) thereby bridging the package pin and HMC body. Ammonium hydroxide present in this bridged epoxy was causing the low electrical isolation at ambient condition. The electrical isolation that resulted from the ammonium hydroxide is quantified and the results were found comparable with the measured values. At elevated temperatures, the ammonium hydroxide again decomposes to ammonia and water vapor and loses its conductivity and the isolation values become normal. [ABSTRACT FROM AUTHOR]

In this paper, we report an easy route for preparing new metal nanorod-polymer composites consisting of gold nanorods, Au NRs, and temperature responsive copolymer "microgel" particles. The microgel particles of ~200 nm in size, which contain carboxylic acid groups, were prepared by surfactant-free emulsion polymerization of a selected mixture made of N-isopropylacylamide and acrylic acid in the presence of a cross-linker N,N0-methylenebisacrylamide. The electrostatic interactions between the cationic cetyltrimethylammonium bromide (CTAB) stabilized Au NRs and anionic microgel particles were expected to occur in order to prepare stable Au NRs-microgel composite particles. The optical and structural characterization of the composite was achieved using UV-Vis spectroscopy, Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and dynamic light scattering (DLS). TEM image shows that Au NRs are attached on the surface of the microgel particles. Dynamic light scattering measurements prove that the composite particles are temperature responsive, which means the particles undergo a decrease in size as the temperature increases above its phase transition temperature. In vitro cytotoxicity of the composite materials were tested by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Lactate dehydrogenase (LDH), and hemolysis assay, which showed non-toxicity (biocompatibility). [ABSTRACT FROM AUTHOR]

The paper by Gershoni-Poranne and Chen (R. Gershoni-Poranne, P. Chen, Chem. Eur. J. 2017, 23, 4659) gives an incorrect definition of covalent bonding. Furthermore, the assignment of so-called charge shift bonds in ammonium compounds has no physical foundation and is conceptually redundant. [ABSTRACT FROM AUTHOR]

A response to the comment by Gernot Frenking, outlining common ground, as well as differences, with regard to a recent paper on charge-shift bonding in quaternary ammonium cations. [ABSTRACT FROM AUTHOR]

Oxidized chitin nanocrystals (ChNCs) were isolated from crab shell chitin using ammonium persulfate (APS) method. The oxidized ChNCs were in needle shape with a diameter of 15 nm, the length of 400–500 nm, and crystallinity index of 93.5%. Carboxymethyl cellulose (CMC)-based films reinforced with the ChNCs (0, 1, 5, and 10 wt.%) were flexible and transparent. The mechanical strength of the CMC film increased significantly ( p < 0.05) after blending with the ChNCs. The tensile strength (TS) and elastic modulus (EM) increased by 88% and 243% when 10 wt.% of ChNCs were incorporated. Water vapor barrier property of the composite films decreased and the hydrophilicity increased compared with the neat CMC film. The oxidized ChNCs obtained using the APS method have a high potential for being used as a reinforcing filler to improve the mechanical properties of nanocomposite films for the application in food packaging, nano-papers, hydrogels as well as biomedical applications. [ABSTRACT FROM AUTHOR]

This paper collects experimental data and mathematical modelling of Nd(III), Tb(III) and Dy(III) solvent extraction with an ionic liquid prepared from Aliquat 336 (Methyl-tri(octyl/decyl)ammonium chloride) and Oleic Acid (AliOle). Extraction experiments were carried out to evaluate the effect of chloride anion in aqueous phase, AliOle and REE concentrations over the extraction extension. Mathematical models computed with Matlab software were derived from the mass balances and chemical equilibria involved in the extraction system of Neodymium(III), Terbium(III) and Dysprosium(III) individually. The optimized equilibria parameters proposed fit accurately the experimental data and allowed us to predict the extraction extension of each metal from an aqueous mixture. [ABSTRACT FROM AUTHOR]

Primary NO x control methods used on coal fired utility boilers utilize ammonia- and urea-based processes. These processes result in some ammonia exiting the treatment zone, which can react with SO 3 /H 2 SO 4 in the coal fired flue gas to form ammonium bisulfate (ABS). This ABS formation can lead to potential balance of plant operational issues: • deposition on the SCR NO x control ammonia injection components in cases of insufficiently heated dilution air for ammonia transport • deposition on catalyst surfaces during low load operation, reducing catalyst activity • deposition in the cold end baskets of the air preheater Mitigating these impacts requires an accurate understanding of the ABS formation temperature as a function of flue gas composition. Five past studies of ABS formation temperature exhibit a very large variation. This paper provides a critical review of these studies, along with new experimental data, in order to show that ABS formation is best described by recent laboratory work, with the ABS formation temperature effectively described by the equation: (1) P NH 3 ( atm ) ∗ P SO 3 ( atm ) = 2.97 ∗ 10 13 ∗ e ( - 54 , 950 / RT ) where R is the universal gas constant (1.987 cal/K-mol) and T is the flue gas temperature in degrees Kelvin (K). With the increase in renewable fuel sources and the increasing use of natural gas for electricity generation, coal fired boilers are called upon to operate over a broader load range. Using the above expression, this work shows that the generally accepted value for ABS formation temperature is nominally 5% (14 K or 25°F) too high. While this difference may seem small, from a practical perspective it can represent substantial operating cost savings, as a large coal fired plant can operate at a lower minimum load than is currently required by the catalyst vendor‘s prescribed SCR minimum operating temperature based on ABS formation temperature from prior work. [ABSTRACT FROM AUTHOR]

The synthesis of mono-sized silica nanoparticle with mesostructures via sol-gel method by employing ammonium polycarboxylate (APC) surfactant has investigated. The major aim of this paper is to introduce APC as an appropriate surfactant to control nucleation and growth of nanoparticles during hydration and condensation steps of the sol-gel process. Dynamic light scattering (DLS) results indicated that the particle in the sol containing APC had an average particle size about 10 nm. The bonds of prepared silica nanoparticles were studied by IR spectroscopy and X-ray photoelectron spectroscopy (XPS). The result of scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM) confirmed that applying APC could sufficiently induce the mass transfer during the synthesis process, this claim have also verified according to the particle size analysis. Resulting information also approved the synthesis of spherical and mono-sized nanoparticle with an average particle size of 25 nm. Furthermore, the synthesized nanoparticles possessed a mesostructured characteristic due to leaving of APC organic components during final heat treatment. N 2 adsorption/desorption porosimetry indicated that the particles were comprised of mesopores with an average pore size of 2.5 nm and specific surface area of 1015 m 2 g −1 . This strategy could be readily applied to prepare an engineered product of silica nanoparticles with uniform spherical morphology and mesostructure. [ABSTRACT FROM AUTHOR]

Berberine and berberine chloride as quaternary ammonium salts belong to the rare 'basic natural dyes'. Berberine is e.g. found in the bark of common barberry. It is a yellow natural dye, which dyers appreciate. It is possible to dye wool or leather even without a mordant. Biosynthesis and total synthesis of berberine are described. As an alkaloid, it shows a variety of physiological effects. Formerly used in traditional medicine it is now under intensive pharmacological investigation. We describe the isolation of berberine chloride from barberry bark without chromatography, present its spectra and their interpretations. Besides, barberry fruits are a piquant delicacy of Persian cuisine. A recipe for dyeing and another one for the kitchen round this paper off. Based on a Bachelor thesis this project is a follow up of the recent book 'Classics in Spectroscopy' by S. Berger und D. Sicker (Wiley-VCH 2009). [ABSTRACT FROM AUTHOR]

• A star-shaped phosphorus-nitrogen intumescent flame retardant (BTETP) based on triazine was synthesized. • BTETP was combined with ammonium polyphosphate (APP) to form intumescent flame retardants systems (IFRs) to flame-retard polypropylene. • Flame retardancy and thermal stability improved significantly by the combination of BTETP and APP. • Excellent flame retardancy can be achieved owning to condensed and gas phase synergistic flame-retardant mechanism. In this paper, a star-shaped char forming agent BTETP containing phosphorus and nitrogen is synthesized and characterized in the paper. It is compounded with ammonium polyphosphate (APP) to form an intumescent flame-retardant system. The stable star-shaped structure is constructed, and the insulating char layer is formed on the surface of the polymer matrix by the synergistic effect between phosphorus and nitrogen, thus, the high-performance flame retardant PP is obtained. Its flame retardancy and thermal stability are studied by limiting oxygen index (LOI), vertical combustion test (UL-94), cone calorimetry (CCT), and thermogravimetric analysis (TGA). With only a 20 wt% addition of BTETP/APP (1:2), the PP composite can reach the UL-94 v-0 level, while the peak heat release rate (PHRR), total heat release rate (THR), and average mass loss rate (AV-MLR) are significantly reduced compared with pure PP, showing higher fire safety. Moreover, the residue at 800 °C can reach as high as 9%, indicating that the loading of BTETP/APP is conducive to promoting carbonization of the degradation products of PP to generate more char. In addition, the synergistic effect and the flame retardant mechanism are studied and discussed. This study provides a program for the synthesis of flame retardants with a high-performance and effectively avoids the problem existing in traditional flame retarding approaches. [ABSTRACT FROM AUTHOR]

Alkaline or alkaline earth octahydrotriborate M(B 3 H 8 ) x and dodecahydro- closo -dodecaborate M x B 12 H 12 (M = Li, Na, Mg or Ca with x = 1 or 2) have recently attracted a lot of interest for hydrogen storage and solid electrolyte applications. Nevertheless, their syntheses are still a roadblock for large scale applications. In this paper we propose a novel approach for their syntheses starting from the cheapest borohydride NaBH 4 . The process involves first the solvothermal synthesis of tetrabutylammonium octahydrotriborate (C 4 H 9 ) 4 NB 3 H 8 (TBAB 3 H 8 ) being the basis for the syntheses of the others boranes. Starting from TBAB 3 H 8 , we have synthesized pure and unsolvated NaB 3 H 8 by salt metathesis reaction with sodium tetraphenylborate. Then, we have successfully obtained Na 2 B 12 H 12 by solvothermal decomposition of NaB 3 H 8 . This approach has shown to be quantitative and reproducible, which could lead to the development of these boranes in real life applications. [ABSTRACT FROM AUTHOR]

This paper reports the phase equilibrium temperature and dissociation heat of ionic semiclathrate hydrate formed with tetrabutylammonium butyrate (TBABu). The temperature – composition phase diagram of the TBABu hydrate was determined in the mass fraction from 0.10 to 0.44. The highest equilibrium temperature of TBABu hydrate was 15.4 °C in the mass fraction range from 0.35 to 0.37. On the dissociation heat of DSC measurements, a single heat flow peak of TBABu hydrate excluding ice melting peak was observed at all the mass fraction systems. The largest dissociation heat was 184.9 ± 3.1 kJ/kg at the mass fraction 0.36. TBABu hydrate could potentially be used as a thermal energy storage material. [ABSTRACT FROM AUTHOR]

We review recent understanding of the crystallographic phases and its relation to ferroelectricity in ammonium lithium sulphate (NH4LiSO4) using the crystal structural data reported before and present our recent idea about its ferroelectricity. In this paper, we also report phase transitions and crystal structure at room temperature of tori-ammonium lithium di-sulphate ((NH4)3Li(SO4)2) from our recent experimental results. NH4LiSO4which is one of the (NH4)2SO4family ferroelectrics and (NH4)3Li(SO4)2which is one of theA3B(XY4)2-type derived from theABXY4-type were crystallized by evaporating the aqueous solution at room temperature. The phase transition and crystal structure were studied by means of thermogravimetric analysis, differential scanning calorimetry and single-crystal X-ray diffraction. In addition, phase transitions and ferroelectricity of NH4LiSO4will be discussed from the crystal structural changes. [ABSTRACT FROM PUBLISHER]

The paper presents a technique for the synthesis of molybdenum carbide using mechanical activation of carbon black, which was impregnated with a 20% aqueous solution of ammonium heptamolybdate (AHM) using the incipient wetness technique, in an inert medium at a 100 g acceleration of milling bodies for 30 min. The mechanically activated carbide-containing composites were calcined in an inert medium at 800 °C. The composites were examined by a range of physical methods. It was shown that the mechanically activated composite consists of molybdenum carbide, iron oxide and iron carbide (about 4–8% according to AES-ICP). The phase addition method was used to determine the quantitative content of Мо 2 С, which was equal to 7.2 wt% in the calcined sample. Catalytic testing of mechanically activated molybdenum carbide in the partial oxidation of methane showed that the carbide-containing catalyst provides a 48–60% conversion of methane and an 83–85% selectivity for the target product (CO). [ABSTRACT FROM AUTHOR]

The effects of cobalt acetate (CoAc), manganese acetate (MnAc), nickel acetate (NiAc) and zinc acetate (ZnAc) as fire retardant additive in intumescent polypropylene (PP) formulations containing PP/ammonium polyphosphate (APP)/pentaerythritol (PER) are reported. The limiting oxygen index (LOI) and vertical burning (UL94) tests and cone calorimetry were used to quantify the enhancement. Environmental chamber rheometry, thermal gravimetric analysis and the morphology of the residual char were used to investigate the mechanism of enhancement. The incorporation of small quantities of metal acetates had a significant influence on the fire behaviour. As an example, 0.7 wt% MnAc improved the UL 94 rating of PP/APP + PER (mass ratio 100/25, with APP/PER = 3/1) sample from V-2 to V-0, while 1 wt% MnAc reduced the peak heat release rate and the total heat release by 18% and 12% in the cone calorimeter. Rheological data, cone calorimetry, and photographs of the residual char showed how the fire retardancy of the systems were affected by the melt viscosity, which depended on the loading of metal acetate. During thermal decomposition, the metal acetates promote the crosslinking of the polymer and the fire retardant, reinforcing the protective intumescent layer. While, the effect is most potent at the optimal metal loadings. At higher MnAc loadings, the benefit of a stronger char is overwhelmed by the adverse effect of crosslinking on the transition char layer. Thus, this paper offers a new insight into the mechanism of the intumescent fire retarded PP system. [ABSTRACT FROM AUTHOR]

In this paper the interfacial behavior of aqueous solutions of cationic gemini surfactants of the, N,N′-bis(dimethylalkyl)-α,ω-alkanediammoniumdibromide type (known as the 12-s-12 series), in the absence and presence of ZnO nanoparticles was studied. Equilibrium and dynamic interfacial tension between n- decane and aqueous surfactant solutions were investigated. It was concluded that the synergistic effect between surfactants and nanoparticles increases the surfactant efficiency with respect to reducing the interfacial tension. Moreover, the magnitude of the effect of ZnO nanoparticles on the interfacial tension decreases with increasing length of the spacer group in the gemini surfactant structure. Dynamic studies illustrate that the migration mechanism of gemini surfactants (regardless of the presence of ZnO) from the bulk to the interface was controlled by both diffusion and adsorption. The effect of spacer length on the contact angle and emulsion stability both with and without nanoparticles was also studied. [ABSTRACT FROM AUTHOR]

An analytical chemistry method has been developed to quantitatively recover microgram quanties of solid uranium oxides from swipe media using ammonium bifluoride (ABF, NHHF) solution. Recovery of uranium from surrogate swipe media (filter paper) was demonstrated at initial uranium loading levels between 3 and 20 µg filter. The optimal conditions for extracting UO and UO are using 1 % ABF solution and incubating at 80 °C for one hour. The average uranium recoveries are 100 % for UO, and 90 % for UO. With this method, uranium concentration as low as 3 µg filter can be recovered for analysis. [ABSTRACT FROM AUTHOR]

This paper presents a novel methodology to recover gold from waste electrical and electronic equipment (WEEE) using ammonium persulfate ((NH 4 ) 2 S 2 O 8 ). Gold was recovered as a fine coating using substrate oxidation without shredding or grinding process. The WEEE sample was characterized giving values of Au: 1.05 g/kg, Fe: 86.00 g/kg, Ni: 73.64 g/kg, Cu: 26.65 g/kg. The effect of (NH 4 ) 2 S 2 O 8 concentration (0.22–1.10 M), oxygen (0.0–1.4 L/min) and L/S ratio (10–30 mL/g) on the main responses (substrate oxidation and Au recovery) was investigated implementing response surface methodology with numerical optimization. A quadratic model was developed and quantities greater than 98% of Au were recovered. The findings presented suggest that, optimized quantities of ammonium persulfate in aqueous highly oxygenated media could be used to extract superficial gold from WEEE. [ABSTRACT FROM AUTHOR]

Ammonium dihydrogen phosphate (NH4HPO4, ADP) crystal can be used to generate second, third and fourth harmonics. In this paper, the growth characteristics of ADP and the differences between the growth solubility and structures of potassium dihydrogen phosphate (KDP) and ADP crystal are discussed in detail. Ex situ atomic force microscopy (AFM) was applied to explore the growth morphology of ADP crystal at different supersaturation values. A series of ADP crystals were grown, and the transmission spectra of ADP crystals across the whole transmission region were measured. Laser-induced damage threshold (LDT) was measured, and was found to be higher than the average value of LDT of KDP and 70% deuterated DKDP crystals. [ABSTRACT FROM AUTHOR]

In the paper, Brandon mathematical model that describes the relationship between the essential fabrication parameters [reduction temperature (T R ), calcination temperature (T C ), calcination time (t C ) and reduction time (t R )] and specific surface area of ammonium diuranate (ADU)-derived UO 2 powder products was established. The proposed models can be used to predict and control the specific surface area of UO 2 powders prepared through ADU route. Suitable temperatures for conversion of ADU and ammonium uranyl carbonate (AUC) was examined with the proposed model through assessment of the sinterability of UO 2 powders. [ABSTRACT FROM AUTHOR]

This paper describes the Cu(OTf)2-mediated coupling of aryl and heteroaryl trifluoroborates with tetrabutylammonium or alkali metal salts to form C-O, C-N, and C-halogen bonds. The reactions proceed under mild conditions (often room temperature over 16 hours) with carboxylate, halide, and azide salts, all nucleophiles that have been underrepresented in the copper cross-coupling literature. Preliminary results show that copper salts bearing weakly coordinating X-type ligands are essential for enabling these transformations to proceed under mild conditions. [ABSTRACT FROM AUTHOR]

Abstract: Near-infrared (NIR) and mid-infrared (MIR) spectroscopy are irreplaceable methods for characterization of bentonites. The paper presents work on bentonites modified with inorganic Na+ and organic HDTMA+ (hexadecyltrimethylammonium) cations and treated by 1.5, 3, 4.5 and 6M H2SO4. The characterization was based on the assignment of the stretching (ν) and bending (δ) vibrations observed in the MIR region and the first overtone [2ν(R–H)] and combination [ν(R–H)+ δ(R–H)] modes of R–H groups (R=O, C) in the NIR region. NIR spectrum shows the characteristic OH and CH bonds for organomontmorillonite. The effect of larger alkylammonium cations on the vibrations of Si–O and OH bonds in montmorillonite layers is observed. A few key-bands in the NIR region show the change of water in the interlayer montmorillonite. The intensities of the overtone (7080 and 6840cm−1) and combination (5242cm−1) bands of H2O have considerably decreased as a result of hydrophobic character of the NaOM. Spectra of acid-treated samples show a gradual decrease in the intensities of the OH overtone (near 7100–7000cm−1) and combination bands (4600–4300cm−1) reflecting a fewer number of octahedral atoms. This paper also points out that ATR technique and the 2nd derivative spectrum enables much precise band assignment. [Copyright &y& Elsevier]

This paper presents the preparation of γ-MnS thin films from three different chemical baths having the chemicals manganese acetate, triethylamine, ammonium chloride, hydrazine hydrate and thioacetamide. The preparative parameters were optimized to obtain good quality MnS thin films. The reaction of formation of MnS was discussed in this paper. XRD analysis is employed to confirm the structure and nature of γ-MnS thin films. The calculated crystallite size ranges from 40-54 nm, indicating that the as-prepared MnS films are made up of nanocrystals. EDAX spectra enabled to identify the film as Mn1.2S0.8. SEM pictures showed the hollow spherical morphology of the prepared γ-MnS thin films. FTIR spectra of γ-MnS thin films have also been analyzed and discussed in this paper. [ABSTRACT FROM AUTHOR]

Abstract: The effect of surfactants sodium dodecyl sulphate (SDS) and cetyltrimethyl ammonium bromide (CTAB) on the surface roughness, surface morphology and surface topography of electroless nickel (EN)–phosphorus surface protective coating obtained from an alkaline bath is presented in this paper. In this study the influence of surfactant concentrations on the surface roughness of coated samples were investigated. It was observed that the surface roughness, surface morphology and surface topography of Ni–P coating were clearly influenced by the addition of surfactants SDS and CTAB. EN deposits with addition of surfactant SDS and CTAB at a concentration of 0.6g/l produce a smooth surface and the average roughness (R a) value is 1.715μm for SDS and 1.607μm for CTAB which is less than the R a value of EN deposit without surfactant addition (1.885μm). The mean average roughness (R a) value with addition of surfactant is 1.796μm. EN deposit with addition of surfactants consists of a significant fraction of particles of nickel. In the presence of SDS, fine nickel particles have dispersed uniformly on the substrate surface resulting in smoother surface finish of the deposited layers. In the presence of CTAB, at lower concentrations (upto 0.6g/l) coalescence of nickel particles have been deposited on the substrate surface and at the higher concentration (above 0.6g/l) uniformly improved surface finish of the deposited layer is resulted. The complete experimental details, results obtained and their analysis are presented in this paper. [Copyright &y& Elsevier]

Anthropogenic acid precursor emissions in Asia are increasing at a significant rate and this is expected to continue for the next several years. This paper comprises of studies that included sulfate, nitrate and ammonium around Asian countries (China, Korea, Japan and Taiwan) in recent years. The paper also provides the water-soluble ionic fine and coarse particulate concentrations in these Asian countries in recent years. Fine and coarse particulates in Taiwan (Kaohsiung and Talchung) and China (Nanjing and Shanghai) were found to have higher sulfate (average 18.68 and 15.75 μg/m3) and nitrate (average 12.77 and 7.71 μg/m3) concentrations than any other Asian country. The average sulfate concentrations for Japan and Korea were 7.31 and 5.84 μg/m3, respectively. The average nitrate concentrations for Japan and Korea were 6.73 and 4.65 μg/m3, respectively during the years 1998–2001. The different sample collection devices, analysis methods and pollutant concentrations are discussed in this study. The purpose of this study is to arrange the atmospheric water-soluble ionic species (SO42- and NO3-) investigations in the Asian region. The data obtained here can also help to understand the sources, concentrations, phase distribution and health impact of atmospheric water-soluble ionic species (SO42- and NO3-) in other Asian regions. [ABSTRACT FROM AUTHOR]

Stainless steel, polymethylmethacrylate and polytetrafluoroethylene coupons were analysed for surface topographical and adhesion force characteristics using tapping mode atomic force microscopy and force-distance microscopy techniques. The two polymer materials were surface modified by polishing with silicon carbide papers of known grade. The struvite scaling rate was determined for each coupon and related to the data gained from the surface analysis. The scaling rate correlated well with adhesion force measurements indicating that lower energy materials scale at a lower rate. The techniques outlined in the paper provide a method for the rapid screening of materials in potential scaling applications. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are considered to be very promising group of chemicals and the number of their potential applications is growing rapidly. However, while these compounds were originally proposed as a green alternative to classical solvents, there are certain doubts as to whether this classification is correct. Although in recent years there have been first reports published proving the presence of some ILs in the environment and even in human blood, at this point the scale of this possible problem is not yet fully understood. However, there is no doubt that as the number of ILs applications increases, analytical capabilities for rapid detection of possible environmental contamination should be also considered. Therefore, in this review paper, recent evidences for the ILs environmental contamination as well as analytical achievements related to the extraction of ILs from various environmental matrices have been summarized and important gaps and future perspectives have been pointed out. Based on the presented data it might be concluded that there is the urgent need for further development towards risk assessment of these potential environmental contaminants. [Display omitted] • ILs are beginning to be detected in different environmental matrices. • The most commonly studied ILs are the ammonium compounds. • The number of studies on the analysis of ILs in environmental matrices is limited. • Reliable methods for the determination of ILs in environmental matrices are needed. [ABSTRACT FROM AUTHOR]

In this paper we report the synthesis, the crystal structure and the optical response of APbX 3 (A=MA, DMA, and TMA; X=I, Br) hybrid organic-inorganic materials including some new phases. We observe that as the cation group increases in size, the optical absorption edge shifts to higher energies with energy steps which are systematic and independent on the anion. A linear correlation between the optical bad gap and the tolerance factor has been shown for the series of samples investigated. [ABSTRACT FROM AUTHOR]

Aqueous waste streams of the metallurgical industry often contain considerable concentrations of metal salts. Previous research showed that the metal chloride salts of zinc(ii), manganese(ii) and iron(iii) can be recovered by solvent extraction using a sustainable and renewable fatty acid based ionic liquid as the extractant. In this paper, the extraction mechanism of Zn(ii), Co(ii) and Ni(ii) from chloride media has been studied systematically. The metal extraction performances of the precursors, sodium oleate and tetraoctylammonium chloride, were compared to the extraction performance of the ionic liquid tetraoctylammonium oleate. Slope analysis experiments were performed to determine the number of ionic liquid molecules involved in the extraction. The experimental data showed that Co(ii) and Ni(ii) were extracted in the pH range from 6 to 8 by the formation of negatively charged metal carboxylate complexes with tetraalkylammonium counter ions. In contrast, Zn(ii) gets extracted as a mixed metal chloride carboxylate anionic complex with tetraalkylammonium counter ions. This extraction mechanism was supported by EXAFS measurements. [ABSTRACT FROM AUTHOR]

The aim of this paper is the characterization of pure tobelite synthesized in the system (NH 4 ) 2 O-Al 2 O 3 -SiO 2 -H 2 O, which is a first, indispensable step for accurately interpreting the data obtained in more complex chemical systems. Tobelite has been synthesized at hydrothermal conditions (200 ± 3 °C), using a solid:solution ratio (in weight) = 1:15, and reaction times from 1 to 90 days and has been characterized by X-ray diffraction; infrared and Raman spectroscopy; differential thermal analysis and thermogravimetry; and transmission-analytical electron microscopy. The average chemical composition of tobelite formed after 90 days run time, determined by combining the analytical electron microscopy data with nitrogen determination in the solid products of the reaction by elemental analysis, was [NH 4 Al 1.98 (Si 3.07 Al 0.93 )O 10 (OH) 2 ]. The refinement of the X-ray diffraction patterns indicated that the 1 M polytype predominates, and the determined cell-parameters were: a = 5.219 (0.004) Å; b = 9.021 (0.007) Å; c = 10.556 (0.009) Å; β = 101.41° (0.08); V = 487.23 (0.69) Å 3 . The infrared spectra indicated the presence of two υ 4 bands (at 1403 and 1435 cm − 1 ), which can be related to the presence of two main tobelite populations with mean particle sizes of 400 × 60 and 2000 × 200 Å. The thermal study by means of differential thermal analysis and thermogravimetry, combined with X-ray thermodiffraction suggested that the mechanisms of NH 4 loss were different in the two differently-sized tobelite populations: the thinner particles showed a low thermal stability (between 380° and 440 °C) and the NH 4 loss was coupled with dehydroxylation, leading directly to the decrease of the tobelite content. Loss of NH 4 from the thicker particles occurred between 440° and 500 °C, causing a gradual contraction of the basal spacing, which was followed by dehydroxylation. There were no previous data of Raman spectroscopy of tobelite and this study presents its most characteristic features. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP) has a much lower dissolution rate and solubility than calcite, especially in an acidic environment, so it has been proposed for the protection of marble against acidic rain corrosion. Promising results were obtained, but further optimization is necessary as the treated layer is often incomplete, cracked and/or porous. In this paper, several parameters were investigated to obtain a coherent, uncracked layer, and to avoid the formation of metastable, soluble phases instead of HAP: the role of the pH of the starting solution; the effect of organic and inorganic additions, and in particular that of ethanol, as it is reported to adsorb on calcite, hence possibly favoring the growth of the HAP layer. Finally, a double application of the treatment was tested. Results were compared to those obtained with ammonium oxalate treatment, widely investigated for marble protection. Results indicate that adding small amounts of ethanol to the formulation remarkably increases the acid resistance of treated samples, and yields better coverage of the surface without crack formation. The effectiveness of the treatment is further enhanced when a second treatment is applied. The efficacy of ethanol-doped DAP mixtures was found to be remarkably higher than that of ammonium oxalate based treatments. [ABSTRACT FROM AUTHOR]

A novel and efficient approach to sulfonamides has been developed. Using TBHP as the oxidant and NH4I (20 mol%) as the catalyst, arylsulfonyl hydrazides reacted with amines to provide sulfonamides in moderate to good yields. Possible reaction pathway for the formation of the products was also discussed in this paper. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the pressure drop and heat transfer characteristics of a coil heat exchanger in which TBAB hydrate slurry is being formed from a 36.5 wt % TBAB solution. The coil heat exchanger has a 5.6 mm internal diameter. First tests were carried out with water in order to validate the experimental method. TBAB hydrates are formed by cooling the mixture of TBAB and water at temperatures from 20 °C to 11 °C. Experimental heat transfer coefficients and pressure drop of TBAB hydrate slurry have been obtained with solid concentrations in the range of 10–45 wt %. The results are compared with values for TBAB solution and water. Existing pressure drop prediction methods can reasonably predict the experimental data. The experimental data cannot be predicted with existing heat transfer prediction methods. A method is proposed for the prediction of heat transfer under hydrate formation conditions. [ABSTRACT FROM AUTHOR]

Chitosan derivatives organic montmorillonite first prepared by stepwise assembly method, then which be used to prepare quaternised carboxymethyl chitosan of organic modified montmorillonite silver (QCOM-Ag) by complex impregnation; finally using X-ray diffraction analysis, SEM to characterise the structure and morphology of samples; antimicrobial properties of multiple samples tested by filter paper method and multiple dilution method. The results showed the synthesis of silver carboxymethyl chitosan quaternary complex solution intercalation by its intercalation into cetyltrimethyl ammonium bromide organic modified montmorillonite layer, and the layer spacing of up to 0·998 nm. With the mass ratios of quaternised carboxymethyl chitosan to organic montmorillonite increased from 1:1 to 8:1 in QCOM nanocomposites, the results also showed that the characterisation of chitosan after the silver surface is rough, there is little particulate matter evenly dispersed in the surface thereof. SEM micrographs showed that Ag NP was mainly spherical, and few had square or bar form. Compared with carboxymethyl groups, quaternary ammonium groups are more beneficial to prepare Ag NP, and silver has been loaded onto QCOM. Inhibition experiments showed that this bacteriostatic ring-controlled, sustained intermediate Gram-positive bacteria S. aureus has a good antibacterial effect; minimal inhibitory concentration of QCOM-11-Ag antibacterial liquid for B. subtilis obtained by multiple experiments was 200 μg mL−1. The antibacterial effect of QCOM-11-Ag on B. subtilis is more obvious, yet minimal inhibitory concentrations of S. aureus and E. coli are 500 and 250 µg mL−1, respectively. [ABSTRACT FROM AUTHOR]

In this paper we report the study of electric properties of bis-tetrapropylammoniumhexchlorostannte compound. The plots of − Z ʺ versus Z ′ obtained in a range of temperature (343–393 K ) and frequency (209 Hz to 5 MHz) were well fitted to an equivalent circuit formed by a parallel combination of resistance ( R ), fractal capacitance (CPE) and capacitance ( C ). The frequency dependence of A.C. conductivity has been fitted using Jonscher relation at different temperatures σ ( ω ) = σ d c + A ω s . The variation of the exponent s with temperature indicates that the CBH model is the probable mechanism for the A.C. conduction behavior. The theoretical study of A.C. electrical conduction using single polaron model has been reported. The study of the activation energy obtained from the electric modulus matches well with that obtained from conduction. [ABSTRACT FROM AUTHOR]

The mean particle size and size distribution of Ammonium Di-Uranate (ADU) particles, precipitated during the precipitation reaction of Uranyl Nitrate Pure Solution (UNPS) with ammonia play an important role on the sintered density of UO 2 pellets. The quality of precipitated ADU depends on number of process parameters viz. , pH of UNPS, concentration of uranium in UNPS, flow rate of ammonium hydroxide, temperature etc. However, the effects of the presence of free acid and entrained Tri-Butyl-Phosphate (TBP) in UNPS on the quality of ADU powder were not studied till date. Experiments were conducted to study the effect of free acidity and the presence of entrained TBP on the quality of precipitated ADU particles. It was found that as the concentration of free acid as well as the concentration of entrained TBP in UNPS increases, the particle size of precipitated ADU decreases. Based on the experimental results two correlations were developed to determine the mean particle size of ADU; one is based on the free acid content of UNPS and the other is based on the content of entrained TBP in UNPS, which is used for the precipitation. It was found that the correlated values are well fitted with the experimental data within ±3% errors for both the cases. Both these correlations are applicable when other process parameters remain constant. The experimental details and results are discussed in this paper. [ABSTRACT FROM AUTHOR]