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The paper proposes a method that exhibits operational simplicity for the indirect spectrophotometric determination of oxalate ion. We developed Reactive Blue 4 (RB4) as a sensor by complexation with copper ion as a simple, inexpensive yet selective colorimetric chemosensing ensemble for the recognition of oxalate over other available competitive analytes via indicator displacement assay (IDA) in both solution (aqueous medium) and solid state (paper-based experiment). The addition of oxalate to RB4-Cu2+ complex changed the colour from sky blue to dark blue due to the regeneration of RB4 by the chelation of oxalate as the competitive analyte with Cu2+. The absorbance band increase is linear with oxalate concentration from 1.76 to 49.4 µmol/L with a detection limit of 0.62 µmol/L. This measurement mode did not show any influence of interferences (available anions and ascorbic acid). This approach eliminated the need for the separation stages, enzymatic multiple-step reactions, sample preparation, organic solvent mixture, chemical modifications and equipment developed to a high degree of complexity. The oxalate determination gave results in different real samples such as urine, mushroom and spinach, which demonstrated the applicability of the existing method. Furthermore, this colorimetric system can serve as IMPLICATION molecular logic gate using Cu2+ and oxalate (C2O42-) as inputs and UV-Vis absorbance signal as the output with potential monitoring applications. [ABSTRACT FROM AUTHOR]

This paper presents a preliminary scientific investigation of pigments used by Martiros Sarian, a prominent Armenian artist known for his vibrant and evocative paintings. The study focuses on five of Sarian's paintings from different periods of his career, namely, Morning in Stavrino, Arabian Dancer, Caravan, Yerevan Zangu River, and Kirovakan, dated between 1909 and 1948. Non-destructive techniques, including micro-attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging and X-ray fluorescence (XRF), were employed to characterize the pigments in the samples extracted from these paintings. The results reveal the presence of various pigments, including ultramarine blue, cobalt blue, cobalt cerulean blue, viridian, emerald green, cobalt green, celadonite green, cadmium yellow, chrome yellow, Venetian red, yellow ochre, red ochre, lead white, zinc white, and calcium carbonate. Additionally, metal carboxylates and oxalates, degradation products associated with the paint layers, were observed and discussed. The findings contribute to a better understanding of Sarian's artistic technique and provide valuable insights for the conservation and restoration of his artworks. [ABSTRACT FROM AUTHOR]

Blue dyes are relatively uncommon in nature, and a novel dithiophene dye (RanB) is reported in this paper. This dye is derived from an old anti-osteoporotic drug and is a metal ion complexing agent, displaying a planar molecular structure, with two sets of carboxylate, isonitrile, thiophene, and iminodiacetate groups. The blue color originates from a strong absorption peak at 648 nm, accompanied by an unusual fluorescence at 555 nm, with higher energy compared to the main absorption band. RanB forms complexes with lanthanoid ions through the iminodiacetate groups and serves as an effective sensitizer for Tb3+ ions, heightening their emission and improving their use as luminescent agents. Its photo-physical properties and the interaction with Tb3+ have been investigated using absorption spectroscopy, steady-state and time-resolved fluorescence spectroscopy, along with computational methods (ZINDO/S and DFT). The RanB toxicity in human umbilical vein endothelial cells has also been tested, showing a lack of toxicity, holding promising prospects for application as a luminescent and coloring agent in pharmaceuticals and food. [ABSTRACT FROM AUTHOR]

The ancient lacquer films excavated from Dongshan Han tomb M6 of the Western Han Dynasty in Taiyuan City, Shanxi, China, were found sensitive to pH variation. This paper aims to demonstrate the pH-dependent warping behaviors of the ancient lacquer film and discuss their mechanism. The samples were analyzed by surface analytical techniques including attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray photoelectron spectrometry. The results suggest that the outer layer of the lacquer film is more oxidized than the inner layer and contains more carboxylates, with calcium ions and possibly ammonium cations as counter ions. The carboxylates are speculated to be formed by oxidative cleavages in the urushiol side chains and hydrolysis of glycerides of drying oils. The shrinkage and swelling of the lacquer film can be regulated by the type of cations (H+, Ca2+, Na+) of carboxylates through hydrogen bonds, coordination bonds and static forces. Due to the higher content of carboxylates in the outer part, it shrinks more at low pH causing warping outward and swells more at high pH causing warping inward. This paper may provide an important reference for pH control and help resolve the warping problem during conservation or restoration of ancient lacquerware. [ABSTRACT FROM AUTHOR]

Coordination bonding of Ni(II) tetraazamacrocyclic (TAMC) complexes to carboxylic groups of organic polymers and graphene oxide paper (GOP) is proposed for a facile generation of paramagnetic centers by combining two diamagnetic components. The coordination functionalization occurs under basic conditions in water solution at room temperature. The coordination configuration of central Ni(II) changes from tetracoordinated square-planar to hexacoordinated pseudooctahedral, which implies the conversion from low-spin to high-spin nickel centers. In the case of organic polymers, the coordination bonding of Ni(II) macrocycles gives rise to characteristic changes in coloration (from yellow-orange to violet-blue), as well as clearly manifests itself in UV–visible, FTIR and EPR spectra. In the case of GOP, in addition to evident changes in FTIR spectra, morphological alterations in the mat surface and an increase in the mat thickness are observed in SEM images, which can be explained by an intercalating effect of voluminous macrocyclic cations, as well as by partial disintegration of GOP structure due to the liquid-phase treatment. The effective magnetic moments of tetraazamacrocycles attached to organic polymers vary from 0.88 to 1.47 BM, whereas for GOP considerably higher values of 2.10 and 2.87 BM were obtained. [ABSTRACT FROM AUTHOR]

The combination of nanoparticles and polycarboxylate ether superplasticizers is expected to simultaneously improve the durability and mechanical properties of mortar and concrete. However, the uniform dispersion of nanoparticles in cement materials has always been a difficult challenge. In this paper, nanoparticles are modified with surfactants to provide a research direction for better dispersion of nanoparticles in cementitious materials. Modified allyl ether polycarboxylate superplasticizer with short-branched chains was synthesized from acrylic acid and allyl glycidyl ether. Nano-silica/polycarboxylate ether was obtained by grafting nano-silica onto polycarboxylate ether molecular chains through intermolecular dehydration, thus achieving a homogeneous dispersion of nano-silica in the cementitious material. The results show that nano-silica/polycarboxylate ether has better dispersibility in cement matrix and strong clay resistance, which compensates for the poor dispersion of polycarboxylate ether synthesized from conventional polyethylene glycol graft chains in the presence of clay impurities. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, modified polyurethane prepolymer was synthesized by the segmental synthesis method using isophorone diisocyanate (IPDI), hydroxyl-terminated silicone, and polyether glycol dimethylolpropionic acid as raw materials. After that, pectiniform polycarboxylate, of which side chains were in roughly the same polymerization degree and main chains were in different lengths, was synthesized at normal temperature in the complex initiation system of H2O2, APS, sodium bisulfite, and Vc. Then, compared with commercial Sika polycarboxylate, their applications in ultrahigh-performance concrete (HUPC), including flowability, strength, drying shrinkage, and autogenous shrinkage, were investigated. The results showed that, due to the molecular structure of polyorganosiloxane, the synthesized polycarboxylate could be better dispersed. Dosage of silica fume could effectively improve the compressive strength of UHPC, while slag had a certain negative impact on its strength. Incorporation of slag and silica fume could effectively reduce the dry shrinkage of UHPC. [ABSTRACT FROM AUTHOR]

Solar-driven evaporation as a sustainable water purification technology exhibits great potential in solving the global water crisis. In this paper, a novel solar evaporator was successfully prepared with the reduced graphene oxide (rGO) and silver (Ag) nanowires as photothermal conversion media which were loaded into the sodium alginate (SA) hydrogel. It was found that the evaporation rate of the prepared evaporator reached 2.02 kg m−2 h−1 and the solar energy efficiency was 91% under one sun irradiation intensity. Furthermore, this novel solar evaporator exhibited expectant evaporation performance in the treatment of seawater and heavy metal sewage with excellent ion removal ability, with the removal efficiency of various ions higher than 99.9%. The ion-crosslinked SA hydrogel contained in the evaporator ensured the rejection of multivalent ions based on the distribution of carboxylate anions, and the three-dimensional porous channel of the super-hydrophilic hydrogel provided the convenient path for the transport of water molecules and the escape of water vapor. The binary composition of rGO and silver nanowires enhanced the photothermal conversion and the thermal conductivity, which was beneficial to the stable supply of thermal energy for evaporation. The purpose of this paper is to provide reference for promoting the practical application of solar evaporation. [ABSTRACT FROM AUTHOR]

Phosphate (P) is the plant macronutrient with, by far, the lowest solubility in soil. In soils with low P availability, the soil solution concentrations are low, often below 2 [µmol P/L]. Under these conditions, the diffusive P flux, the dominant P transport mechanism to plant roots, is severely restricted. Phosphate is sorbed into various soil solids, Fe/Al oxides, clay minerals and, sometimes overlooked, humic Fe/Al surfaces. The immobilization of P in soil is often the result of the diffusion of P into the internal surfaces of oxides or humic substances. This slow reaction between soil and P further reduces the availability of P in soil, leading to P fixation. The solubilization of soil P by root-released carboxylates is a promising way to increase the acquisition and uptake of P from P-fixing soils. Citrate and, sometimes, oxalate are effective with respect to additional P solubilization or P mobilization, which may help increase the diffusive P flux into the roots by increasing the P solution concentrations in the rhizosphere. The mobilization of humic-associated P by carboxylates may be an effective way to improve soil P solubility. Not only orthophosphate anions are mobilized by root-released carboxylates, but also higher phosphorylated inositol phosphates, as the main part of P esters in soil are mobilized by carboxylates. Because of the rather strong bonding of higher phosphorylated inositol phosphates to the soil solid phase, the mobilization step by carboxylates appears to be essential for plants to acquire inositol-P. The ecological relevance of P mobilization by carboxylates and its effect on the uptake of P by crops and grassland species are, at best, partially understood. Plant species which form cluster roots such as white lupin (Lupinus albus L.) or yellow lupin (Lupinus luteus L.) release high rates of carboxylates, mainly citrate from these root clusters. These plant species acquire fixed or low available P which is accessible to plants at rates which do not satisfy their P demand without P mobilization. And white lupin and yellow lupin make soil P available to other plants in mixed cropping systems or for subsequent plant species in crop rotations. The mobilization of P by carboxylates is probably also important for legume/grass mixtures for forage production. Species such as alfalfa, red clover or white clover release carboxylates. The extent of P mobilization and P uptake from mobilized P by legume/grass mixtures deserves further research. In particular, which plant species mostly benefit from P mobilization by legume-released carboxylates is unknown. Organic farming systems require such legume/grass mixtures for the introduction of nitrogen (N) by forage legumes into their farming system. For this agricultural system, the mobilization of soil P by carboxylates and its impact on P uptake of the mixtures are an important research task. [ABSTRACT FROM AUTHOR]

Understanding carboxylate transport through lipid membranes under physiological conditions is critical in biomedicine and biotechnology, as it allows for the emulation of biological membrane functions and can enhance the absorption of hydrophobic carboxylate-based drugs. However, the structural diversity of carboxylates has made it challenging to study their transport, and the limited available examples do not provide a comprehensive understanding of the role of the organic moiety in this process. Here, we present an in-depth analysis of the diffusion and transport of various aliphatic and aromatic carboxylates into liposomes. We assessed the influence of their size, number of carboxylate groups, and presence of hydroxyl groups. Our findings from fluorescence assays, using lucigenin and HPTS as probes, revealed that most carboxylates can spontaneously diffuse into liposomes in their protonated state, facilitated by the efflux of HNO3 when using NaNO3 solutions at pH 7. The Cl-ISE assay showed chloride/carboxylate exchange by a synthetic anion transporter. Clear trends were observed when the organic moiety was systematically varied, with a particular enhancement of anion transport by the presence of hydroxyl groups in the aromatic carboxylates. Our findings provide insights into the processes by which carboxylates can enter liposomes, which can contribute to understanding the transport of other biologically relevant organic anions. [ABSTRACT FROM AUTHOR]

Abstract The ancient lacquer films excavated from Dongshan Han tomb M6 of the Western Han Dynasty in Taiyuan City, Shanxi, China, were found sensitive to pH variation. This paper aims to demonstrate the pH-dependent warping behaviors of the ancient lacquer film and discuss their mechanism. The samples were analyzed by surface analytical techniques including attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray photoelectron spectrometry. The results suggest that the outer layer of the lacquer film is more oxidized than the inner layer and contains more carboxylates, with calcium ions and possibly ammonium cations as counter ions. The carboxylates are speculated to be formed by oxidative cleavages in the urushiol side chains and hydrolysis of glycerides of drying oils. The shrinkage and swelling of the lacquer film can be regulated by the type of cations (H+, Ca2+, Na+) of carboxylates through hydrogen bonds, coordination bonds and static forces. Due to the higher content of carboxylates in the outer part, it shrinks more at low pH causing warping outward and swells more at high pH causing warping inward. This paper may provide an important reference for pH control and help resolve the warping problem during conservation or restoration of ancient lacquerware.

The effect of individual nanometals (Co, Fe, Cu, Ge) carboxylates (NMC) as components of the suspension for seeds inoculation with rhizobia on the nitrogen fixation rate and the parameters of CO2 and H2O gas exchange in soybean plants grown under different water conditions was investigated. The scheme of trials included the following variants: 1 - seeds + strain B1-20; 2 - seeds + (strain B1-20 + nano-cobalt carboxylate); 3 - seeds + (strain B1-20 + nano-ferrum carboxylate); 4 - seeds + (strain B1-20 + nano-cuprum carboxylate); 5 - seeds + (strain B1-20 + nano-germanium carboxylate). The results showed that during the flowering period, drought (30% field capacity) significantly reduced the rates of nitrogen fixation (Nfx), CO2 net assimilation (An), and transpiration (Tr) in soybean plants. Inoculation of seeds by rhizobia with NMC before sowing reduced the negative effect of drought on these physiological processes. Close correlations were found between the rates of Nfx and An and the stomatal conductance for CO2 and An rates. It was concluded that pre-sowing treatment of seeds by rhizobia with NMC mitigates the negative effect of drought on the main components of soybean-rhizobia symbiosis productivity formation - nitrogen fixation and CO2 assimilation, and also contributes to their recovery after the removal of the stressor. The most effective for this was the use of Ge and Fe nanoparticle carboxylates. [ABSTRACT FROM AUTHOR]

The micellar shape of octyl ether octaethylene oxide carboxylic acid ([H+][C 8 E 8 c−]) is restricted to spheres. A classical core–shell micellar regime (L 1) at lower surfactant concentrations transitions into a regime of head-group interdigitated micelles (L 1 ′) at higher concentrations. In the surfactant's sodium or calcium salts the micelles are deformed from spherical to slightly prolate spheroidal. The formation of a hexagonal (H 1) phase within the transition regime between L 1 and L 1 ′ is possible by a reduction of the area per molecule by counterion bridging. An increase in temperature decreases the influence of ion bridging and 'melts' the H 1 phase into a nematic phase (N) consisting of shorter chains of prolate micelles with a preferential orientation (grey arrow). [Display omitted] In a recent paper, we determined the phase behavior of an aqueous solution of octyl ether octaethylene oxide carboxylic acid ([H+][C8E8c−], Akypo™ LF2) and with partial replacement of H+ by Na+ and Ca2+. It was found that even the neat surfactants are liquid at room temperature and that they form only direct micelles for any aqueous content and over large temperature ranges. The aim of the present work was to find an explanation for the clouding in these systems as well as for the coacervation observed at very low surfactant content. We expected that very similar phase diagrams would be found for a full replacement of H+ by the mentioned ions. We established the respective phase diagrams of the above-mentioned salts in water and determined the structures of the occurring phases in detail with small-and wide-angle X-ray scattering, small-angle neutron scattering, dynamic light scattering, heat flux differential scanning calorimetry, as well as surface tension, ESI-MS, and NMR experiments. To our surprise, we discovered a new type of nematic phase between an isotropic and a hexagonal phase. Based on the complete description of all occurring phases both in the acidic and the charged surfactant systems, we were able to design a coherent and unified picture of all these phases, including the auto-coacervation at low surfactant concentration, the non-conventional clouding at high temperatures, the unusual liquid crystalline phases in a small domain at high surfactant concentrations, and the L β phase at low temperatures and at very low water content. It turned out that all phenomena are a consequence of the subtle interplay between a) the packing constraint due to the very large head-group, b) the relatively small hydrocarbon chain and c) the tunable electrostatic interactions versus entropy. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Education & Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• The single and binary adsorption of amoxicillin and doripenem on HKUST-1 was evaluated. • Interpretation of the single and binary adsorption mechanisms at different temperatures. • Description the competitive effect via statistical physics model. • Simulation of the adsorption process via DFT. The adsorption of amoxicillin (AMX) and doripenem (DRPNM) on copper benzene-1,3,5-tricarboxylate (HKUST-1) in single and binary systems is analyzed in this paper. The experimental results showed that the adsorption capacities of this MOF for the removal of these pharmaceuticals reduced from single to binary solutions. A monolayer adsorption model and its extended competitive version were successfully applied to analyze the adsorption data. The modeling results showed that the reduction of AMX and DRPNM adsorption capacities was explained by a competitive effect of these adsorbates generating an antagonistic behavior for both molecules where the same adsorption site was involved during their removal. The statistical physics model was also utilized to estimate the AMX and DRPNM adsorption orientation on the HKUST-1 surface. Adsorption energies were calculated confirming an exothermic removal process for both molecules and DFT simulations allowed to determine the role of hydrogen bonding in the adsorption mechanism. It was concluded that the interactions for the adsorption of DRPNM on this MOF were higher than those for AMX removal. Particularly, the oxygens linked to the cupper ions on MOFs structure played a crucial role during the adsorption mechanisms of these organic compounds. Overall, this paper presents a combination between experiment results and two different theoretical approaches to provide a new explanation of the mechanism of adsorption of two relevant antibiotics on HKUST-1 MOF. [ABSTRACT FROM AUTHOR]

Gold magnetic nanoparticles (GoldMag) have attracted great attention due to their unique physical and chemical performances combining those of individual FeO and Au nanoparticles. Coating GoldMag with polymers not only increases the stability of the composite particles suspended in buffer but also plays a key role for establishing point-of-care optical tests for clinically relevant biomolecules. In the present paper, poly(4-styrenesulfonic acid-co-maleic acid) (PSS-MA), a negatively charged polyelectrolyte with both sulfonate and carboxylate anionic groups, was used to coat the positively charged GoldMag (30 nm) surface. The PSS-MA-coated GoldMag complex has a stable plasmon resonance adsorption peak at 544 nm. A pair of anti-D-dimer antibodies has been coupled on this GoldMag composite nanoparticle surface, and a target protein, D-dimer was detected, in the range of 0.3-6 μg/mL. The shift of the characteristic peak, caused by the assembly of GoldMag due to the formation of D-dimer-antibody sandwich bridges, allowed the detection. [ABSTRACT FROM AUTHOR]

This paper focuses on the obtaining of carboxylate precursors through the redox reaction of cobalt nitrate and ethylene glycol, in different stoechiometric ratios, as well as the decomposition of precursors into cobalt oxides. The influence of the NO3−:C2H6O2 stoichiometric ratio on the formation of the precursors is studied through thermal analysis, FTIR spectroscopy and acido-basic analysis (conductometric/potentiometric titrimetry). Phase analysis by XRD and FTIR of the powders obtained at the decomposition of the precursors at 400°C has evidenced the formation of CoO for a high NO3-: C2H6O2 synthesis ratio and of Co3O4 for a low NO3−:C2H6O2 ratio. The Scherrer equation and scanning electron microscopy (SEM) were used to determine the dimensions of the nanoparticles obtained. [ABSTRACT FROM AUTHOR]

Carboxylates are ideal directing groups because they are widely available, readily cleavable and excellent linchpins for diverse follow-up reactions. However, their use in meta-selective C−H functionalizations remains a substantial unmet catalytic challenge. Herein, we report the ruthenium-catalyzed meta-C–H alkylation of aromatic carboxylic acids with various functionalized alkyl halides. A bidentate N-ligand increases the electron density at the metal center of ortho-benzoate ruthenacycles to the extent that single-electron reductions of alkyl halides can take place. The subsequent addition of alkyl radicals is exclusively directed to the position para to the CAr–Ru bond, i.e., meta to the carboxylate group. The resulting catalytic meta-C−H alkylation extends to a wide range of (hetero)aromatic carboxylic acids including benzofused five-membered ring heteroarenes but no pyridine derivatives in combination with secondary/tertiary alkyl halides, including fluorinated derivatives. It also allows site-selective C5−H alkylation of 1-naphthoic acids. The products are shown to be synthetic hubs en route to meta-alkylated aryl ketones, nitriles, amides, esters and other functionalized products. Carboxylates are ideal directing groups for aryl C–H functionalizations, given their wide availability and relative ease of functional group interconversion; however, their potential in meta-selective functionalizations has not been fully realized. Here, the authors use carboxylates for meta-selective alkylations via ruthenium catalysis. [ABSTRACT FROM AUTHOR]

A series of 4-ferrcenylbutyl carboxylate esters with different alkyl chain length (C2-C4) of carboxylic acids were synthesized using Fe3O4@SiO2@(CH2)3-Im-bisEthylFc[I] nanoparticles as catalyst and have been characterized with FT-IR, 1H NMR, and 13C NMR. Ferrocenyl-based esters were used as corrosion inhibitors of mild steel in the 1M HCl solution as corrosive media. The corrosion inhibition efficiency of the synthesized ferrocenyl-based esters has been assessed by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The 4-ferrocenylbutyl propionate showed a more effective corrosion inhibition behavior among the studied esters with 96% efficiency after immersion in the corrosive media for 2 weeks. The corrosion inhibition mechanism is dominated by formation of passive layer of inhibitor on the surface of the mild steel by adsorption. Moreover, the adsorption characteristics of 4-butylferrcenyl carboxylate esters on mild steel were thoroughly explored using density functional theory calculations. It was found that the Fe atoms located around the C impurity in the mild steel are the most efficient and active sites to adsorb 4-butylferrcenyl carboxylate esters. [ABSTRACT FROM AUTHOR]

This review presents an overview of the biological applications of coordinative compounds based on unsaturated carboxylates accompanied by other ligands, usually N-based heterocyclic species. The interest in these compounds arises from the valuable antimicrobial and antitumor activities evidenced by some species, as well as from their ability to generate metal-containing polymers suitable for various medical purposes. Therefore, we describe the recently discovered aspects related to the synthesis, structure, and biological activity of a wide range of unsaturated carboxylate-containing species and metal ions, originating mostly from 3d series. The unsaturated carboxylates encountered in coordinative compounds are acrylate, methacrylate, fumarate, maleate, cinnamate, ferulate, coumarate, and itaconate. Regarding the properties of the investigated compounds, it is worth mentioning the good ability of some to inhibit the development of resistant strains or microbial biofilms on inert surfaces or, even more, exert antitumor activity against resistant cells. The ability of some species to intercalate into DNA strands as well as to scavenge ROS species is also addressed. [ABSTRACT FROM AUTHOR]

Interaction of the pre-organized complex of iron(II) trimethylacetate and 1,10-phenanthroline (phen) [Fe2(piv)4(phen)2] (1) (piv = (Me)3CCO2−)) with 1,6-diaminohexane (dahx) in anhydrous acetonitrile yielded a 1D coordination polymer [Fe3O(piv)6(dahx)1.5]n (2) and an organic salt of pivalic acid (H2dahx)(piv)2 (3). The structure of the obtained compounds was determined by single-crystal X-ray diffraction analysis. The phase purity of the complexes was determined by powder X-ray diffraction analysis. According to the single-crystal X-ray analysis, coordination polymer 2 is formed due to the binding of a triangular carboxylate core {Fe3(μ3-O)(μ-piv)6} with an aliphatic diamine ligand. Thermal behavior was investigated for compounds 1 and 2 in an argon atmosphere. [ABSTRACT FROM AUTHOR]

Although the term nanozymes was coined by us in 2004 to highlight the enzyme-like properties of gold nanoparticles passivated with a monolayer of Zn(II)-complexes in the cleavage of phosphate diesters, systems resembling those metallo-nanoparticles, like micelles and vesicles, have been the subject of investigation since the mid-eighties of the last century. This paper reviews what has been done in the field and compares the different nanosystems highlighting the source of catalysis and frequent misconceptions found in the literature. [ABSTRACT FROM AUTHOR]

During the examination of two 19th century oil paintings by Swiss artists, the Reading pastor (ca. 1885) by Ferdinand Hodler (1853-1918) and Portrait of a young girl (ca. 1888) by Filippo Franzoni (1857-1911), it was observed that in particular locations, the surface had an unusually granular texture, given by the application of metallic particles and the presence of large translucent green agglomerates. In this paper we investigate the composition and origin of the metal particles and green agglomerates. A combination of bulk analysis (GC-MS and FTIR) and analytical microscopy techniques (X-ray tomographic microscopy, light microscopy, ATR-FTIR-FPA imaging and SEM-EDX) were used. It was concluded that the metal particles are composed of a lower quality brass (copper/zinc alloy) and ground from foil. The current appearance resulted from the reaction of the brass and its corrosion products with the fatty acids in the surrounding paint/varnish matrix. This has lead to the formation of agglomerates of zinc and copper carboxylates, the latter responsible for their green colour. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are fascinating clay-like materials that display versatile properties, making them an extremely fertile playground for diverse applications, ranging from bio-compatible materials to the pharmaceutical industry to catalysis and photocatalysis. When intercalating organic and bio-organic species between the inorganic layers, such materials are named hybrid LDHs. The structure–property relation in these systems is particularly relevant, since most of the properties of the materials may be fine-tuned if a comprehensive understanding of the microscopic structure in the interlamellar space is achieved, especially with respect to the reorganization under water uptake (swelling). In this work, we combined experiments and simulations to rationalize the behavior of LDHs intercalating three carboxylates, the general structure of which can be given as [ Mg 4 Al 2 (OH) 12 ] A 2 − · XH 2 O (with A 2 − = succinate, aspartate, or glutamate and X representing increasing water content). Following this strategy, we were able to provide an interpretation of the different shapes observed for the experimental water adsorption isotherms and for the evolution of the infrared carboxylate band of the anions. Apart from small differences, due to the different reorganization of the conformational space under confinement, the behavior of the two amino acids is very similar. However, such behavior is quite different in the case of succinate. We were able to describe the different response of the anions, which has a significant impact on the isotherm and on the size of the interlamellar region, in terms of a different interaction mechanism with the inorganic layer. [ABSTRACT FROM AUTHOR]

In the title compound, C20H17BrO5S, molecules are connected by intermolecular C--H...S hydrogen bonds with R22(10) ring motifs, forming ribbons along the baxis direction. C--H...π interactions consolidate the ribbon structure while van der Waals forces between the ribbons ensure the cohesion of the crystal structure. According to a Hirshfeld surface analysis, H...H (40.5%), O...H/H...O (27.0%), C...H/H...C (13.9%) and Br...H/H...Br (11.7%) interactions are the most significant contributors to the crystal packing. The thiophene ring and its adjacent dicarboxylate group and the three adjacent carbon atoms of the central hexene ring to which they are attached were refined as disordered over two sets of sites having occupancies of 0.8378 (15) and 0.1622 (15). The thiophene group is disordered by a rotation of 180° around one bond. [ABSTRACT FROM AUTHOR]

This paper describes acid-catalysed reactions of 5,7-dimethoxy-1-methylindole and methyl 5,7-dimethoxyindole- 2-carboxylate with a range of aldehydes and ketones. The former indole reacts selectively at C3, whereas the latter reacts preferentially at C4 but also at C3 depending on the reaction conditions. Reactions of indoles with 2,2-dimethoxypropane and triethyl orthoformate are also reported. A range of di- and triindolylmethanes are described, together with an indolo-triptycene of novel structure. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the formation and decomposition of silica embedded metal carboxylates obtained using Co-, Fe- and Ni- nitrates and polyols with different structure and molecular weight (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2,3-propanetriol). The thermal behavior of carboxylate precursors (oxalic, malonic, lactic, hydroxymalonic and succinic) is similar for all used polyols, both the formation and decomposition of precursors occurring in two stages. However, the mass loss slightly increases with increasing of the diol chain length and significantly increases with the presence of a supplementary, nonreactive secondary hydroxyl group. X-ray diffraction shows the formation of NiO single phase or NiO and CoFe 2 O 4 mixtures below 750 °C, and of mixed Co-Ni ferrite single phase at 1000 °C, while Fourier transformed infrared spectroscopy confirms the formation of silica matrix and the formation and decomposition of carboxylate precursors. Transmission electron microscopy shows spherical nanoparticles of different size. The Ni 0.5 Co 0.5 Fe 2 O 4 nanocrystallites size (4.3–28.1 nm) and relative crystallinity (4–100 a.u.) increase with the annealing temperature, the diol chain length and the distance between hydroxyl groups. The coercive field (0.015–0.6 T) and saturation magnetization (21.5–25 emu/g) of gels annealed at 1000 °C also increase for longer chain length diols. [ABSTRACT FROM AUTHOR]

Hydrothermal reactions of 2-(2',4'-dicarboxylphenoxy) benzoic acid (H3L) with 1,4-di(pyridin-4-yl)benzene (dpb) and 1,4-bis(2-methylimidazol-3-ium-1-yl)benzene (bimib) in the presence of Mn(OAc)2⋅4H2O and Zn(NO3)2⋅6H2O yielded three new coordination polymers, [Mn1.5(L)(dpb).H2O].H2O (1), [Zn3(L)2( bimib)]n (2) and [Zn3(L)2( bmimb)]n (3), complex 1 has a three dimensional structure formed by the combination of mono and binuclear chains, complexes 2 and 3 have identical structures with one only different in the length of the auxiliary ligands, both complexes have 3D structure. All the complexes were characterized by IR, XRD, PXRD, and thermal gravemetric analysis (TGA), furthermore the magnetic bevior of complex 1 was studied; which showed antiferromagnetic behavior. [ABSTRACT FROM AUTHOR]

This paper presents a preliminary scientific investigation of pigments used by Martiros Sarian, a prominent Armenian artist known for his vibrant and evocative paintings. The study focuses on five of Sarian’s paintings from different periods of his career, namely, Morning in Stavrino, Arabian Dancer, Caravan, Yerevan Zangu River, and Kirovakan, dated between 1909 and 1948. Non-destructive techniques, including micro-attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging and X-ray fluorescence (XRF), were employed to characterize the pigments in the samples extracted from these paintings. The results reveal the presence of various pigments, including ultramarine blue, cobalt blue, cobalt cerulean blue, viridian, emerald green, cobalt green, celadonite green, cadmium yellow, chrome yellow, Venetian red, yellow ochre, red ochre, lead white, zinc white, and calcium carbonate. Additionally, metal carboxylates and oxalates, degradation products associated with the paint layers, were observed and discussed. The findings contribute to a better understanding of Sarian’s artistic technique and provide valuable insights for the conservation and restoration of his artworks.

Objective: Unfortunately, infectious diseases are still one of the most important health problems around the world. The resistance of pathogenic bacteria to several drugs is an important and growing problem in the treatment of infectious diseases and hospital infections. It seems necessary to identify new compounds that have inhibitory or lethal effects on this bacterium. That's why we decided antimicrobial efficacy. The newly synthesized compound (2-methyl-1,3-dioxo-',11',2',3',5',6',7'a,7-octahydrospiro] inden-'2,3-pyrrolizidine 2-carboxylate (5) on Staphylococcus aureus and Escherichia coli bacteria. Methods: At first, synthesized of methyl'2-methyl-1,3-dioxo-1',1',2',3',5',6', 7',7'a, -octahydrospiro] inden-'2,3-pyrrolizidine 2-Carboxylate was prepared by green chemistry method and with the help of microwave in one pot. Microbial culture media containing control bacteria of Staphylococcus aureus and Escherichia coli were prepared and concentrations of 70 to 110 Landa of the above compound were added to the samples. The antimicrobial property of the samples was determined after 3 days using the disk diffusion method and broth micro dilution method was determined, as well as the minimum inhibitory concentration and bacterial lethality of the samples Results: The minimum inhibitory concentration and bacterial lethality in the above combination against the same standard strain of Escherichia coli bacteria was obtained at the rate of 12.5 µg/mL. The minimum inhibitory and lethal concentration of methyl methacrylate compound against the standard strain of Staphylococcus aureus bacteria was 12.5 and 25 µg/mL, respectively. Conclusion: The use of the above combination was effective in controlling and inhibiting the tested bacteria. [ABSTRACT FROM AUTHOR]

Fumarate-alumoxane nanoparticles (Fum-ANPs) incorporated PES nanofiltration membrane was fabricated via phase inversion to achieve favorable performance as the enhancement in the dye removal and antifouling capacity. FTIR spectra of the Fum-ANPs revealed that the carboxylate and hydroxyl functional groups were created on the surface of Fum-ANPs. The strong affinity of Fum-ANPs functional groups with water molecules made the membrane surface more hydrophilic. Hence, the modified membrane sample had a higher pure water flux than the bare one. Zeta potential data showed that the Fum-ANPs blended PES membrane was negatively charged at a pH value of 6, which is favorable for negatively charged solute rejection. The antifouling behavior of the membranes was analyzed using powder milk solution (8 g/L) in a dead-end filtration system. The obtained results demonstrated that the introduction of Fum-ANPs in the membrane matrix ameliorated the antifouling behavior of the resulting membrane. To further study the performance of the Fum-ANPs incorporated PES membrane, removal of Direct red 16 dye was tested. The removal efficiency of Direct red 16 with the Fum-ANPs blended PES membrane was 99% while it was 88.2% for the bare membrane sample. [ABSTRACT FROM AUTHOR]

Nanotechnology is playing a significant role in modern life with tremendous potential and promising results in almost every domain, especially the pharmaceutical one. The impressive performance of nanomaterials is shaping the future of science and revolutionizing the traditional concepts of industry and research. Titanate nanotubes (TNTs) are one of these novel entities that became an appropriate choice to apply in several platforms due to their remarkable properties such as preparation simplicity, high stability, good biocompatibility, affordability and low toxicity. Surface modification of these nanotubes is also promoting their superior characters and contributing more to the enhancement of their performance. In this research work, an attempt was made to functionalize the surface of titanate nanotubes with carboxylic groups to increase their surface reactivity and widen the possibility of bonding different molecules that could not be bonded directly. Three carboxylic acids were investigated (trichloroacetic acid, citric acid and acrylic acid), and the prepared composites were examined using FT-IR and Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The toxicity of these functionalized TNTs was also investigated using adherent cancer cell lines and fibroblasts to determine their safety profile and to draw the basic lines for their intended future application. Based on the experimental results, acrylic acid could be the suitable choice for permanent surface modification with multiple carboxylic groups due to its possibility to be polymerized, thus presenting the opportunity to link additional molecules of interest such as polyethylene glycol (PEG) and/or other molecules at the same time. [ABSTRACT FROM AUTHOR]

High salinity has been a major challenge in oil recovery. Here, two binary systems composed of sodium fatty alcohol polyoxyethylene ether carboxylate (AECM) and cationic surfactants, cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPyCl) were developed. Their fundamental properties; namely, oil/water interfacial tension, wettability, emulsification, adsorption, and oil‐washing were investigated and compared. The results showed that both AECM–CTAB (4:6–7:3, m/m) and AECM–CPyCl (5:5–6:4, m/m) could decrease oil/water interfacial tension below 10−2 mN/m. Even the total salinity was close to 200,000 mg/L after 7 days of quartz sand adsorption, showing a good interfacial activity and excellent anti‐adsorption properties. All these compound drives could effectively change the wettability of the glass surface, which reduced the contact angle to a minimum of 54.76°. In addition, the emulsification time could reach up to 24 h at 85°C, with excellent emulsification performance at high temperatures. The oil washing efficiency could reach 74.68% after 48 h. According to our comprehensive analysis, the best formulation was obtained at AECM/CTAB ratio of 5:5. [ABSTRACT FROM AUTHOR]

Recycling of tailings in the form of cemented paste backfill (CPB) is a widely adopted practice in the mining industry. Environmental performance is an important design criterion of CPB structures. This environmental performance of CPB is strongly influenced by its saturated hydraulic conductivity (permeability). Superplasticizers are usually added to improve flowability, but there is a limited understanding of their influence on the hydraulic properties of the CPB. This paper presents new experimental results on the variations of the hydraulic conductivity of CPB containing polycarboxylate-based superplasticizer with different compositions and curing conditions. It is found that the hydraulic conductivity of the CPB decreases with the addition of superplasticizer, which is beneficial to its environmental performance. The reduction is largely attributable to the influence of the ether-based superplasticizer on particles mobility and cement hydration. Moreover, both curing temperature and time have correlations with the hydraulic conductivity of CPB containing superplasticizer. In addition, the presence of sulfate and partial replacement of PCI with blast furnace slag reduces the hydraulic conductivity. The variations are mainly due to the changes in the pore structure of the CPB. The new results discussed in this manuscript will contribute to the design of more environmental-friendly CPBs, which is essential for sustainable mining. [ABSTRACT FROM AUTHOR]

Recognition of anionic species plays a fundamental role in many essential chemical, biological, and environmental processes. Numerous monographs and review papers on molecular recognition of anions by synthetic receptors reflect the continuing and growing interest in this area of supramolecular chemistry. However, despite the enormous progress made over the last 20 years in the design of these molecules, the design of receptors for chiral anions is much less developed. Chiral recognition is one of the most subtle types of selectivity, and it requires very precise spatial organization of the receptor framework. At the same time, this phenomenon commonly occurs in many processes present in nature, often being their fundamental step. For these reasons, research directed toward understanding the chiral anion recognition phenomenon may lead to the identification of structural patterns that enable increasingly efficient receptor design. In this review, we present the recent progress made in the area of synthetic receptors for biologically relevant chiral carboxylates. [ABSTRACT FROM AUTHOR]

Abstract In this paper structure, thermodynamic, and dynamic properties were investigated for series of selected protic ionic liquids, methylmorpholinium ([MeMorph]+) and ethylmorpholinium ([EtMorph]+) with carboxylate formate ([For]−) and acetate ([Ace]−) anions, using quantum chemical calculations and molecular dynamics simulations. Relative geometrical structure, H atom transfer between anion-cation, charge transfer and the polarizability was calculated and studied. As a result, anion type (characterized by the alkyl chain length) has the major influence on the charge and H atom transfer with subsequent influences on physiochemical properties. Irregularity in the trend of thermodynamic properties of these ILs (observed experimentally) was described by the extent of charge transfer of atom we estimated by scanning the anion-cation distance. Molecular dynamics simulations indicated a substantially lower density for [MeMorph][Ace] than [MeMorph][For], consistent with reported experiment, and demonstrate the high impact of anion type on thermodynamic properties. Radial distribution function g (r), demonstrates cations and anions tightly bond in the first coordinate shell but bond loosely in second and third shells as the anion alkyl chain increases. Adhering to this, special distribution functions demonstrate the more compactness and higher anion distributing around cation for [MeMorph][For] than the other two ILs. As regards the accuracy of simulation of transport property (the viscosity) of ILs, the scaling down of partial-charges was found necessary to account for electrostatic interaction with the nonpolarizable force field used. Required scaling depends on the diversity of anion-cation charge transfer. These simulations, consistent highly with experiment, exclusively provide insight into the details of less impact ILs that would be obtained by larger size alkyl substituent on carboxylate anion. Graphical abstract Unlabelled Image Highlights • Protic morpholinium (with formate and acetate) ionic liquids are simulated by MD. • Charges and detailed anion-cation charge and H transfer is studied by MP2 and DFT. • Anion-cation binding is remained tight up to third shell for the short chain anion. • The reported relative low compactness of IL with long chain anion is elucidated. • Viscosity is simulated agreeably by non-polarizable FF and charges scaled down. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) is a crucial factor affecting the immobilization of heavy metal in wetlands. Recent studies have shown that the rhizosphere SOM has great ability to immobilize heavy metals. However, there existed few works on studying molecular characteristics of SOM to explore the mechanisms. Electrospray ionization–Fourier transform ion cyclotron resonance–mass spectrometry (ESI-FTICR-MS) combined with FTIR spectroscopy were applied to investigate the characteristics of SOM in rhizosphere and nonrhizosphere samples and to find out what characteristics the rhizosphere SOM embodies conducive to metal binding in this paper. The rhizosphere contained higher C, P, Mn, and other metal concentrations. The adsorption of Cr on rhizosphere SOM was greater than that on nonrhizosphere SOM. Compared to nonrhizosphere SOM, rhizosphere SOM contained less saturated and more oxidized compounds, greater overall molecular weights (MW), more condensed aromatic structures (56.59% VS 51.56% by peak intensity), less carboxylate and N-containing COO functional groups (25.98% VS 56.63% by peak intensity), more hydrophilicity, and the latter four are conducive to metal binding. This study showed that the rhizosphere SOM had unique compositional and structural characteristics. These results provided evidence for the phytoremediation technologies of heavy metal contaminated wetlands. [ABSTRACT FROM AUTHOR]

A simple two-stage method for the synthesis of isomeric esters of 2-chloroquinoline-5-, 6-, 7-carboxylic acids by successive oxidation and chlorination reactions of methyl quinoline-5-, 6-, 7-carboxylates has been developed. The target compounds have been obtained in acceptable yields using readily available reagents, simple transformations, and purification methods. Quinoline-8-carboxylic acid ester is unreactive under these conditions. The ester of 2-chloroquinoline-8-carboxylic acid has been obtained with an overall yield of 55 %, starting from 8-methylquinoline. The multi-stage process is paid off by the fact that several transformations occur in one reaction cycle. All the methods developed can be used for the synthesis of target compounds on a multigram scale. Intermediate 2(1H)-oxoquinoline carboxylates are promising compounds in the synthesis of functionalized and condensed heterocycles [ABSTRACT FROM AUTHOR]

The reactivities of various fatty monoacids and diacids on copper metal-containing surfaces were investigated through reflection–absorption infrared spectroscopy. The formation of copper carboxylates is detected on pure copper surfaces, while copper and zinc carboxylates are simultaneously formed on brass surfaces. Following the decrease of acid carbonyl and the formation of carboxylate infrared bands, it is shown that fatty monoacids C8 and C10 react with clean/polished copper and its zinc alloy within 2–4 h, while those with chains > C12 react within days. At the end of the processes, only the corresponding metal carboxylates are detected in all cases. An explanation for the above is offered on a molecular mobility and acidity basis, where the lower monoacids (liquids in room temperature), also having lower pKa values, favor higher reaction rates. Furthermore, it is argued that longer-chain fatty monoacids, when deposited from their solutions, allow for favorable orientation resulting in self-assembled monolayer-type molecular packing on the copper surface, which may additionally rationalize the slower reaction. Interestingly, fatty diacids do not form any carboxylate products under the same conditions, as it is argued that their molecules may efficiently pack as self-assembled multilayers on copper and ultimately protect it. The possible implications of the fatty monoacid and diacid behavior on the archaeological organic residues level and regarding the stability of copper alloys are discussed. [ABSTRACT FROM AUTHOR]

Summary: Resource complementarity can contribute to enhanced ecosystem functioning in diverse plant communities, but the role of facilitation in the enhanced complementarity is poorly understood.Here, we use leaf manganese concentration ([Mn]) as a proxy for rhizosheath carboxylate concentration to explore novel mechanisms of complementarity mediated by phosphorus (P) facilitation.In pot experiments, we showed that mixtures involving Carex korshinskyi, an efficient P‐mobilizing species, exhibited greater biomass and relative complementarity effect than combinations without C. korshinskyi on P‐deficient soils. Compared with monocultures, leaf [Mn] and [P] of species that are inefficient at P mobilization increased by 27% and 21% when grown with C. korshinskyi (i.e. interspecific P facilitation via carboxylates) rather than next to another inefficient P‐mobilizing species. This experimental result was supported by a meta‐analysis including a range of efficient P‐mobilizing species. Phosphorus facilitation enhanced the relative complementarity effect in low‐P environments, related to a greater change in several facilitated species of their root morphological traits relative to those in monoculture.Using leaf [Mn] as a proxy, we highlight a vital mechanism of interspecific P facilitation via belowground processes and provide evidence for the pivotal role of P facilitation mediated by the plasticity of root traits in biodiversity research. [ABSTRACT FROM AUTHOR]

To establish a circular economy, waste streams should be used as a resource to produce valuable products. Biodegradable plastic waste represents a potential feedstock to be microbially recycled via a carboxylate platform. Bioplastics such as polylactic acid food packaging waste (PLA-FPW) are theoretically suitable feedstocks for producing carboxylates. Once feasible, carboxylates such as acetate, n-butyrate, or n-caproate can be used for various applications like lubricants or building blocks for making new bioplastics. In this study, pieces of industrial compostable PLA-FPW material (at 30 or 60 g/L) were added to a watery medium with microbial growth nutrients. This broth was exposed to 70 °C for a pretreatment process to support the hydrolysis of PLA into lactic acid at a maximum rate of 3.0 g/L×d. After 21 days, the broths of the hydrolysis experiments were centrifugated and a part of the supernatant was extracted and prepared for anaerobic fermentation. The mixed microbial culture, originating from a food waste fermentation bioprocess, successfully fermented the hydrolyzed PLA into a spectrum of new C2-C6 multi-carbon carboxylates. n-butyrate was the major product for all fermentations and, on average, 6.5 g/L n-butyrate was obtained from 60 g/L PLA-FPW materials. The wide array of products were likely due to various microbial processes, including lactate conversion into acetate and propionate, as well as lactate-based chain elongation to produce medium-chain carboxylates. The fermentation process did not require pH control. Overall, we showed a proof-of-concept in using real bioplastic waste as feedstock to produce valuable C2-C6 carboxylates via microbial recycling. [ABSTRACT FROM AUTHOR]

The preparations and structural characteristics of three-dimensional Zn(II) metal-organic frameworks (MOFs) with dipyridyl-olefin and tricarboxylate are reported. The solvothermal reactions of zinc(II) nitrate hexahydrate, 1,4-bis [2-(4-pyridyl)ethenyl]benzene (bpeb), and 4,4′,4″,-benzene-1,3,5-triyl-tris(benzoic acid) (H3btb) furnished three Zn(II) MOFs (1–3) with new topologies. Depending on the temperature or mole-ratio variations, self-interpenetrated [Zn2(bpeb)(btb)(OH)]·DMF·H2O (1), noninterpenetrated [Zn3(btb)2(bpeb)]·xSolvent (2), and fourfold interpenetrated [Zn2(Hbtb)2(bpeb)][Zn2(Hbtb)2(bpeb)][Zn4(Hbtb)4(bpeb)2] (3) structures were generated with different molecular building blocks. It is interesting that although all three MOFs contain the same metal cation, anion, and spacer ligand, they show different emissions due to structure and connectivity. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the adsorption behavior of polycarboxylate superplasticizers (PCE) on coarse aggregates with a property of high water consumption (above 2%). The coarse aggregates were ground into a powder to create large bibulous stone powder, and it was observed that significant amounts of the ether-based PCE were absorbed onto large bibulous stone powder. The adsorption rate immediately reached a maximum after 5 min and then gradually decreased until an equilibrium absorption was established after 30 min. Zeta potential, infrared spectroscopy, and thermogravimetric analysis (TGA) measurements confirmed that the polycarboxylate superplasticizer adsorbed on the surface of the stone powder. Hydrodynamic diameter measurements showed that the polycarboxylate superplasticizer molecules were smaller than pore size, and the surface area and pore volume were reduced by the polymer incorporation in the pores. [ABSTRACT FROM AUTHOR]

The paper presents test results of the impact of sulphate ions from calcium sulphates: Hemihydrate, dihydrate and anhydrite, on rheological properties and hydration heat of cement pastes with, and without, superplasticizers, derivatives of maleic (SP-2) and acrylic (SP-1) acids. It is demonstrated that cement pastes fluidity depends on superplasticizer chemical structure, and its effect is expressed by a hydrophilic coefficient. As maleic superplasticizers have flexible comb-like structure composed of a shorter backbone chain containing COO− carboxylate groups and very long side chains, cement pastes showed higher fluidity than with acrylic superplasticizer with ladder-like structure, longer backbone chains with shorter side chains. SP-1 showing lower hydrophilicity coefficient and fewer COO− groups was found to be less sensitive to increased sulphate ion content in pastes. However, with SP-2 with higher hydrophilicity, a gradual fluidity loss (increased paste viscosity) was observed. Plastic viscosity was approximately at the same level in SP-1-containing pastes. Tests showed that sulphates definitely changed polycarboxylate superplasticizers performance. A high concentration of sulphate ions reduced maleic superplasticizer efficiency. Under these conditions, SP-1 is more effective and therefore more suitable for fluidity of pastes containing higher SO42− ions content. Thus, sulphate ions concentration in the paste should be considered when selecting superplasticizer. [ABSTRACT FROM AUTHOR]

Copper phyllosilicates-derived catalysts (CuPS-cats) have been intensively explored in the past two decades due to their promising activity in carbonyls hydrogenation. However, CuPS-cats have not been completely reviewed. This paper focuses on the aspects concerning CuPS-cats from synthesis methods, effects of preparation conditions, and dopant to catalytic applications of CuPS-cats. The applications of CuPS-cats include the hydrogenation of carboxylates, carboxylic acids, carbonates, formyls, and CO2 to their respective alcohols. Besides, important factors such as the Cu dispersion, Cu+ and Cu0 surface areas, particles size, interaction between Cu and supports and dopants, morphologies, and spatial effect on catalytic performance of CuPS-cats are discussed. The deactivation and remedial actions to improve the stability of CuPS-cats are summarized. It ends up with the challenges and prospective by using this type of catalyst. [ABSTRACT FROM AUTHOR]