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A simple, efficient and environmentally benign method has been discussed for the synthesis of aldehydes and ketones by the oxidative decarboxylation of phenylacetic acid under ligand free condition using simple, efficient, preparatively easy, magnetically recoverable and low cost spinel CuFe2O4 nanoparticles. The catalyst was characterised using powder-XRD, FTIR, FE-SEM, EDX, VSM and HRTEM. The recyclability was examined and the results showed that the catalyst remained almost equally active up to five consecutive cycles. Spinel Structured Copper Ferrite is a very efficient nano catalyst for Oxidative decarboxylation of Phenyl acetic acids and can be reused up to five cycles without significant loss in catalytic activity.

To explore the synergism between two metal centers we have synthesized graphene oxide (GO) supported Pd/Cu@GO, Pd@GO and Cu@GO nanoparticles through bio-reduction of Pd(NO3)2 and CuSO4·5H2O using Tulsi (Ocimum sanctum) leaf extract as the reducing and stabilizing agent. The graphene oxide (GO) was obtained by oxidation of graphite following a simplified Hummer's method. The as-prepared nanomaterials have been extensively characterized by FTIR, powder X-ray diffraction (PXRD), HRTEM, TEM-EDS, XPS, ICP-AES and BET surface area measurement techniques. The morphological study of Pd/Cu@GO revealed that crystalline bimetallic alloy type particles were dispersed on the GO layer. The activity of Pd@GO, Cu@GO and Pd/Cu@GO as catalysts for the Sonogashira cross-coupling reaction have been investigated and it was found that the Pd/Cu@GO nanostructure showed highly superior catalytic activity over its monometallic counterparts, substantiating the cooperative influence of the two metals. The inter-atom Pd/Cu transmetalation between surfaces was thought to be responsible for its synergistic activity. The catalyst showed higher selectivity towards coupling of aryl iodides with both aliphatic and aryl alkynes resulting in moderate to excellent isolated yield of the desired products (45–99%). The products have been characterized by GC-MS and 1H-NMR spectroscopic techniques and compared with authentic samples. The Pd/Cu@GO catalyst could be easily isolated from the reaction products and reused for up to at least ten successive runs effectively.

Sm3+ singly doped and Sm3+ co-doped with varying concentration of ZnS nanoparticles (ZnS NPs) in silica matrix were fabricated via sol-gel route and investigated by various structural, thermo-gravimetric and spectroscopic techniques. Structural characterizations were done by XRD, EDX, TEM and FTIR whereas thermo-gravimetric characterization was performed by TGA/DTG technique. The structural studies reveal the presence of nanosized ZnS particles in the amorphous silica matrix. Spectroscopic studies were performed through absorption, excitation, emission and decay spectra of the fabricated samples. The dependence of Judd-Ofelt and various radiative parameters of Sm3+ on the concentration of ZnS NPs in the studied matrix were evaluated. Significantly high value of Ω2 obtained for the present system reveals effective network modifying nature of the ZnS NPs. The PL behaviour showed strong concentration dependence on ZnS NPs and showed optimum for the ZnS concentration of 0.5 M. The emission transition 4G5/2 → 6H9/2 of Sm3+ corresponding to the red colour observed at 642 nm for silica matrix in the present study showed excellent radiative behaviour compared to other popular glass hosts. This indicates ZnS NPs co-doped Sm3+ sol-gel silica matrix to be a prospective candidate for laser and other optical device applications.

A new Fe(II) Schiff base complex anchored on mont-K10 (Fe@imine-mont-K10) was synthesized and extensively characterized by FTIR, powder X-ray diffraction, SEM–EDX, TEM, ESR, X-ray photoelectron spectroscopy (XPS), BET surface area measurement, solid state 29Si NMR and ICP-AES analysis. The catalytic activity of the complex was investigated for hydrogenation of ketones. The results indicated that it exhibited good catalytic activity for hydrogenation of aromatic as well as aliphatic ketones in i-PrOH/CH3CN (1:1) using Na-i-OPr as base at 80 °C resulting in moderate to excellent isolated yields (51–99%) of their corresponding products. The catalyst shows good reusability.

Two copper complexes [(PPh3)2Cu(S2COC2H5)] (A) and [(C3H4N2)2Cu(S2COC2H5)] (B) have been synthesized by the insertion of CS2 in (PPh3)2CuCl2 and (C3H4N2)2CuCl2, respectively in mixed solvent of dichloromethane and ethanol at room temperature. The complexes have been characterized by FTIR and ESR spectroscopy. Both the complexes have been found to be air-stable and are distorted square planar geometry.

The iron oxide was successfully supported on activated clay/carbon through an experimentally viable protocol for both hydrations of nitrile to amide and reduction of nitro compounds to amines. The as-prepared catalyst has been extensively characterised by XPS, SEM-EDX, TEM, TGA, BET surface area measurements and powdered X-ray diffraction (PXRD). A wide variety of substrates could be converted to the desired products with good to excellent yields by using water as a green solvent for both the reactions. The catalyst was recyclable and reusable up to six consecutive cycles without compromising its catalytic proficiency. Activated Mont K10 carbon-supported Fe2O3 is a very efficient and versatile heterogeneous catalytic system for hydration of nitriles to amides and reduction of nitro compounds to amines and can be reused up to six consecutive cycles without significant loss in catalytic activity.

To explore the synergism between two metal centers we have synthesized graphene oxide (GO) supported Pd/Cu@GO, Pd@GO and Cu@GO nanoparticles through bio-reduction of Pd(NO

An efficient heterogeneous photocatalyst composed of Au nanoparticle supported on TiO 2 (anatase) is prepared by sol-gel method. This prepared nanocomposite showed good catalytic activity in the oxidation of various alcohols to aldehyde and ketone under irradiation of visible light. Various spectroscopic techniques including UV–Visible absorption spectral studies and photoluminescence study are employed to characterize the catalyst. It was also characterized by XRD, TEM, BET, XPS and ICP-AES analysis. In contrast to air and H 2 O 2 , use of TBHP as oxidant gave good yield. The reaction conditions with respect to solvent and amount of catalyst are optimized.

Nucleophilic substitution in nitroarenes to form biaryl ethers is of fundamental importance in organic synthesis. Under non-catalytic conditions, this can occur when a highly activated nitroarenes are used, or the nucleophile is activated by strong stoichiometric base. We have established a new method, using ligand-free palladium on carbon (Pd/C) catalyst, for the cross-coupling of activated nitroarenes with relatively non-nucleophilic phenol derivatives, including naphthol, in the absence of harsh bases. Control experiments, hot-filtration, three-phase test and ICP-AES analysis reveals that the catalysis proceeds via a usual oxidative addition step of nitroarene to Pd/C and releases active palladium particles having an extremely high catalytic activity. DFT calculations were made to realize the origin of selectivity of activated nitroarenes.

Monodispersed palladium nanoparticles (PdNp) have been synthesized by a green rapid bio-reduction method under room temperature and pressure. The reducing agents mainly involved in these processes are the various water soluble plant metabolites, polyphenols as well as co-enzymes present in the leaf extract of Tulsi (Ocimum sanctum). An active and stable montmorillonite K-10 supported heterogeneous catalyst was prepared using these PdNp for oxidation of alcohols to their corresponding carbonyl compounds with efficient yield and having good reusability. These are characterized by TEM, XRD, BET surface area and UV–Vis absorption spectroscopy.

A bis-N-heterocyclic carbene (NHC) functionalized with chloropropyltriethoxysilane over silica was used to synthesize a well-defined immobilized palladium complex. This complex is a suitable and easily retrievable catalyst for Suzuki-Miyaura cross-coupling reactions under mild aqueous conditions. Excellent yields and conversions were obtained with low palladium loadings (down to 0.03 mol% Pd). The catalyst can be reused up to six cycles without the loss of its activity. The catalytic role of the NHC complex of palladium during coupling between bromobenzene and phenylboronic acid was investigated theoretically. The oxidative addition step is predicted to be endothermic in agreement with the experimental conditions.

An eco-friendly method for the oxidative transformation of alcohols to their corresponding carbonyl compounds by using $$\hbox {g-C}_{3}\hbox {N}_{4}@\hbox {CuO}$$ as a photoactive heterogeneous catalyst has been developed. The catalyst was characterized by SEM-EDX, TEM, BET surface area measurements, powder XRD, FTIR, photoluminescence and UV-Vis spectroscopy. It was found to be very effective for the conversion of both primary and secondary alcohols into aldehydes and ketones with excellent yields using tert-butyl hydrogen peroxide (TBHP) as oxidant at room temperature in the presence of visible light in aqueous medium. The catalyst can be separated from the reaction mixture by simple centrifugation and reused up to five cycles without significant loss in activity. Hybrid composite of CuO with $$\hbox {g-C}_{3}\hbox {N}_{4}$$ is a very efficient photocatalyst for oxidation of alcohol in aqueous media at room temperature and can be reused up to five cycles without significant loss in catalytic activity. To the best of our knowledge, this is the first example of a photoactive $$\hbox {g-C}_{3}\hbox {N}_{4}@\hbox {CuO}$$ catalyst for the oxidative transformation of alcohol.

Herein, we report a facile methodology for the Suzuki-Miyaura coupling in water. The method involved use of gallic acid (a natural and abundant phytochemical) reduced palladium(0) nanoparticles (PdNPs) formed in situ. The catalyst acts efficiently at low loading with short reaction time, further can be reused effectively till four recycles. Importantly, a wide range of functional groups were found to be compatible with the given reaction conditions. The use of gallic acid influenced both rate of the catalytic reaction and size distribution of the PdNPs. The size, morphology and distribution of the in situ-formed nanoparticles were determined by UV-Vis, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) patterns, Scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) analysis, which showed a uniform gallic acid coated aggregation of palladium particles. Since gallic acid is a non-toxic phytochemical, the present method highlights an efficient alternative for the utilization of natural feedstock.

Silica-immobilized benzamide palladium complex was prepared and characterized. The complex exhibits excellent catalytic activity and stability for Suzuki–Miyaura cross-coupling reaction under mild aqueous reaction condition. Various aryl bromides were coupled with arylboronic acids in i-PrOH/H2O, under open air at room temperature, in the presence of 0.22 mol% of the catalyst to afford corresponding cross-coupled products in high yields. Furthermore, the novel heterogeneous catalyst can be conveniently recovered by simple filtration and reused several times without significant loss in activity.

Department of Chemistry, Dibrugarh University, Dibrugarh-786 004, Assam, India E-mail: dr.pradip54@gmail.com, geetikachem@yahoo.co.in Manuscript received 01 July 2018, accepted 16 July 2018 Biaryls are an important class of organic compounds that occur in many natural products and they have a wide variety of applications in drugs, agrochemicals, dyes, semi-conductors, and asymmetric syntheses. A versatile, eco-friendly, recyclable, heterogeneous catalyst has been developed for the efficient synthesis of symmetric biaryls from aryl boronic acids. The de­veloped protocol for homocoupling of aryl boronic acid to symmetric biaryls is based on copper acetate supported on acid activated Mont K-10 which is ligand free, mild, inexpensive and compatible with wide range of functional groups and exhibit excellent yields. The catalyst is characterised by FTIR, ESR, XRD, SEM-EDX, BET surface area measurement and the cata­lyst can be separated from the reaction mixture by simple centrifugation and reused upto five cycles without significant loss in activity

Silver nanoparticles (AgNPs) of homogeneous size distribution were rapidly synthesized by treating leaf extract of Phlogacanthus thyrsiformis, as reducing agent with aqueous solution of AgNO3, employing a simple, eco-friendly and green synthetic technique. The formed AgNPs were characterized using UV–Vis absorption spectroscopy, SEM and XRD pattern. These AgNPs showed good antibacterial activity against human pathogen Escherichia coli. An active and stable Montmorillonite K-10 (Mont K-10) supported catalyst was prepared using these AgNPs, for oxidation of alcohols with efficient yield and good reusability.

Silver nanoparticles of average sizes ~18-21 nm in diameter were prepared by a green approach via chemical reduction of silver nitrate (AgNO3) using Asiatic Pennywort and Bryophyllum leaf extracts as reducing and capping agents. The bio-reduced silver nanoparticles were characterized by UV-Vis spectroscopic, XRD and TEM techniques. The characteristic surface plasmon band of colloidal solutions of AgNPs synthesized from Asiatic Pennywort and Bryophyllum leaf extracts were found at 445 nm and 405 nm respectively. The results of XRD and SAED pattern showed that the biosynthesized AgNPs have a crystalline structure with cubic phase (fcc). The antimicrobial activities of the as synthesized AgNPs were investigated against gram negative bacteria Pseudomonas Fluorescens and gram positive bacteria Staphylococcus Epidermidis. It was observed that silver nanoparticles obtained from Asiatic Pennywort was more effective on gram positive bacteria Staphylococcus Epidermidis while AgNPs obtained from Bryophyllum was more effective on gram negative bacteria Pseudomonas Fluorescens indicating size dependent activity of AgNPs. Copyright © 2015 VBRI press.

A silica supported palladium catalyst, Pd@imine–SiO2 was prepared by immobilizing Pd(OAc)2 onto silica gel through coordination of imine, generated via Schiff-base condensation between 3-aminopropyltriethoxysilane (APTES) functionalized silica gel and salicylaldehyde. The prepared catalyst was characterized by FT-IR, BET surface area measurements, XRD, SEM-EDX, EDS-mapping and ICP-AES analysis. The imine-based catalyst exhibited excellent activity in the Suzuki–Miyaura cross-coupling reactions of aryl bromides with arylboronic acids in iPrOH/H2O (1 : 1) at room temperature. The reaction proceeds under mild reaction conditions and the catalyst is recyclable, thus offering an environmentally benign alternative to the existing protocols.

We have developed a heterogenized catalyst of Cu(II) complex immobilized onto nanosilica obtained from rice husk (RH), through coordination of imine, generated via Schiff-base condensation between 3-aminopropyltriethoxysilane (APTES) functionalized nanosilica and acetamide. The synthesized catalysts were characterized by FT-IR, XRD, BET surface area measurements, ESR, SEM-EDX and ICP-AES. The synthesized catalyst showed excellent activity towards controlled oxidation of different primary and secondary alcohols in the presence of tert-butyl hydrogen peroxide (TBHP). Furthermore, the catalysts could be recovered by simple filtrations and can be reused upto many consecutive cycles without loss in activity.

An ecofriendly and highly efficient protocol for aerobic oxidative hydroxylation of aryl and heteroaryl boronic acids catalyzed by Ru(III) imine complex immobilized on nanosilica, derived from rice husk, has been developed. The main significance of this protocol is the base free and aerobic reaction condition at room temperature, short reaction time, aqueous reaction medium, and excellent yield of the product. This heterogeneous catalyst is reusable up to sixth cycle without loss in activity.

The easily available montmorillonite clay is treated with phosphoric acid and 10 wt.% is found to be the optimum concentration of phosphoric acid that can be adsorbed chemically on the surface of the clay. Acidity of this phosphoric acid treated montmorillonite clay (PAM) is determined by volumetric as well as potentiometric titration and characterized. Catalytic efficacy of PAM in nitration of various aromatic compounds is reported.

A heterogeneous montmorillonite K-10-supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross-coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross-coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd.

A mild and efficient methodology has been developed for the ipso-hydroxylation of arylboronic acids using montmorillonite K-10 supported silver nanoparticles (AgNPs) as catalyst and aqueous H2O2 as oxidant. The reactions were performed at room temperature within short reaction time under solvent- and base-free conditions. This catalyst shows good reusability.

In this study, we report the development of a new route for the synthesis of polymer–PbS nanocomposite thin film by a novel solar irradiation-induced reaction which is completely free from any complexing agents and toxic chemicals. The as synthesised polymer–PbS thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis absorption spectroscopy. The optical studies showed a direct allowed band gap of PbS lying in the range 1.78–2.2 eV. The XRD pattern shows the cubic structure of PbS with a lattice parameter of 5.927 A. The SEM micrograph of the as-synthesised PbS thin films shows clusters in a relatively loose compact structure in the poly(vinyl alcohol) matrix and separated by voids, which are clearly observed in the surface. However, after annealing, most of the voids disappear in the PbS surface and it is likely that the clusters coalesce giving rise to an homogeneous and compact film. The PbS thin film after annealing is almost pinhole free and as such suit...

An ecofriendly and highly efficient protocol for aerobic oxidative hydroxylation of aryl and heteroaryl boronic acids catalyzed by Ru(III) imine complex immobilized on nanosilica, derived from rice husk, has been developed. The main significance of this protocol is the base free and aerobic reaction condition at room temperature, short reaction time, aqueous reaction medium, and excellent yield of the product. This heterogeneous catalyst is reusable up to sixth cycle without loss in activity.

We have developed a heterogenized catalyst of Cu(II) complex immobilized onto nanosilica obtained from rice husk (RH), through coordination of imine, generated via Schiff-base condensation between 3-aminopropyltriethoxysilane (APTES) functionalized nanosilica and acetamide. The synthesized catalysts were characterized by FT-IR, XRD, BET surface area measurements, ESR, SEM-EDX and ICP-AES. The synthesized catalyst showed excellent activity towards controlled oxidation of different primary and secondary alcohols in the presence of tert-butyl hydrogen peroxide (TBHP). Furthermore, the catalysts could be recovered by simple filtrations and can be reused upto many consecutive cycles without loss in activity.

CdS/PVA nanocomposite thin films have been deposited on glass substrates by in situ thermolysis of precursors dispersed in polyvinyl alcohol (PVA). The synthetic technique reported in this study is free from complexing agent and hence no need to control the pH of the solution as in the case of conventional CBD. The as-prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), UV–vis spectroscopy, and photoluminescence (PL) spectra. The XRD and SAED results indicated the formation of CdS nanoparticles with hexagonal phase in the PVA matrix. The photoluminescence and UV–vis spectroscopy revealed that CdS/PVA films showed quantum confinement effect. From the shift in optical band gap, particle sizes were calculated using effective mass approximation (EMA) method and it was found to be in agreement with the results obtained from TEM observations. The SEM results indicated that as grown films were homogeneous with no visible pinholes and cracks. The film prepared at100 °C was found to be suitable for application as a window layer in solar cell.

The reaction of [Rh(CO)2(µ-Cl)]2 with two molar equivalents of a chiral ligand, (R)-N,N-bis(2-diphenylphosphinoethyl)-1-phenylethylamine(PNP*) yield a mono-carbonyl complex, [Rh(CO)Cl(η2-P,P-PNP*)] (1), in which the potentially tridentate PNP* ligand coordinates in a bidentate fashion through P,P bonding. The complex was characterized by elemental analysis, FAB mass, IR, UV-Vis, 1H- and 31P{1H}-NMR spectroscopy. Variable temperature (223–298 K) 31P{1H}-,NMR spectra of 1 showed a mixture of cis and trans isomers in the solution with the trans predominating at room temperature and the cis at lower temperature. Complex 1 was immobilized on silica through axial coordination of amine from 3-aminopropyltriethoxysilane functionalized silica. The immobilized materials were characterized by elemental analysis (N2), FTIR, DTA–TGA, N2-adsorption, XRD, and SEM analysis.

A thermal characterization of two coal samples from Ledo and Tikak collieries of Makum coalfield, Assam, India using XRD, FT-IR, and TGA was reported in this paper. The coal samples were heated for 20, 40 and 60 min in a 1000-watt heater (temperature ∼ 250 °C) in presence of air and characterized by XRD and FT-IR spectroscopy. Both the coals contain amorphous and crystalline phases. The raw coals also contain very small peaks due to quartz, calcite, gypsum, pyrite, and chlorite. The XRD patterns were found to change upon heating. In the coals heated for 20 and 40 min, it was observed that both amorphous and crystalline parts are common in them; crystalline part being the major one in the 40 min heated samples. The XRD patterns of the samples heated for 60 min indicate the presence of major quantities of α-quartz, hematite, and chlorite in them. They also show some new peaks, which are assigned to be kaolinite, illite, magnetite and very small in comparison to the amorphous portion in raw coals. α-quartz was found to be most stable crystalline phase of silica in the coals. The crystallinity % (X-ray) of the coals heat-treated for different times was determined and found to be increasing with time of heating. The FT-IR spectra of raw and heat-treated coal samples at 250 °C were also recorded and compared. The spectra were observed to be almost similar and it was observed that few functional groups disappear on heating at 250 °C. The same coal samples were also characterized by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. On heat treatment in air atmosphere up to 800 °C, 20–27% weight loss occurs due to removal of various volatile materials. DTA results indicate the chemical reactivity of the coal sample initially at 80–110 °C due to loss of water, and two other major reactions at around 420 and 530 °C due to primary and secondary volatization.

The so-called turbostatic structure of carbons in coal with randomly oriented stacking of the lamellae (graphene) produces intense peaks, which are the dominant features in its X-ray diffraction profiles. The diffractogram may be conveniently divided into two regions of reciprocal space, the medium S region (1 3 A) where S = 4πλ −1sinθ. To better understand the molecular level structure of high sulphur Assam coal, two coal samples (Tirap-1 and Tirap-2) from Tirap colliery of Makum coalfield, Assam (India) has been interpreted in this study by using the X-ray diffraction profiles. Random layered (graphene) structural parameters of these coals were determined by using X-ray diffraction technique, which showed that the L a and L c are 64·99 A and 22·63 A for Tirap-2 and 55·54 A and 23·80 A for that of Tirap-1 coals respectively. The position of γ band was found to be at 4·34 A and 4·13 A for Tirap-2 and Tirap-1 coals respectively. The number of layers and average number of carbon atoms (N) per aromatic graphene were found to be 21 and 8 for both the coal samples. Proximate, ultimate and ash analysis of the two coal samples were also carried out in this investigation.

High sulphur coal sample from Ledo colliery of Makum coalfield, Assam, India was studied using FT-IR and XRD methods. FT-IR study shows the presence of aliphatic -CH, -CH2 and -CH3 groups, aliphatic C-O-C stretching associated with -OH and -NH stretching vibrations and HCC rocking (single and condensed rings). XRD pattern of the coal shows that it is amorphous in nature. Function of Radial Distribution Analysis (FRDA) indicates that coal is lignite in type and there is no evidence of graphite-like structure. The first maximum in the G(r) plot of FRDA at r = 0.14 nm relates to the aliphatic C-C bond (Type C-CH=CH-C), the second maximum at r = 0.25 nm relates to the distance between carbon atoms of aliphatic chains that are located across one carbon atom. The curve intensity profiles obtained from FRDA show quite regular molecular packets for this coal. The coal was found to be lignite in nature.

Two coal samples collected from Makum coal field, Assam, India were studied by XRD and FT-IR techniques. The X-ray diffractogram shows the existence of some crystalline carbons in Assam coals as proven by the appearance of peaks. The radial distribution functional (RDF) method was applied for the determination of structural aspects of the coals. The study indicates that the coals are lignite in type and there is no evidence of graphite-like structures. The maximum in the G(r) plots of function of radial distribution of atoms (FRDA) relates to different distances between carbon atoms of aliphatic chains. The first significant maximum relates to the C-C bond (type C-CH=CH-C), the second maximum relates to the distance between carbon atoms of aliphatic chains that are located across one carbon atom. The curve intensity profiles obtained from FRDA show quite regular molecular packets for this coal. The coals were found to be lignite in nature. FT-IR study shows the presence of aliphatic carbon, C=O and C-O stretching associated with -OH and -NH stretching vibrations. Kaolinite and quartz were also found to be major minerals in Assam coals by FTIR spectroscopy. The difference in intensities of carbonyl groups of the coal samples is likely to relate with the rank.

The imine-based silica-supported palladium catalyst shows excellent activity in the Suzuki—Miyaura cross-coupling of aryl bromides with arylboronic acids under mild reaction conditions.

A mild and efficient methodology has been developed for the ipso-hydroxylation of arylboronic acids using montmorillonite K-10 supported silver nanoparticles (AgNPs) as catalyst and aqueous H2O2 as oxidant. The reactions were performed at room temperature within short reaction time under solvent- and base-free conditions. This catalyst shows good reusability.

A heterogeneous montmorillonite K-10-supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross-coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross-coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd.

Oil field effluent treatment plant (ETP) sludge contains high amounts of hydrocarbon and its disposal by land filling is a problem. Various methods to utilize the sludge and circumvent the disposal problem have been suggested. The high calorific value of the sludge may be used in calcination of clay and manufacture of ceramic materials. This communication reports the kinetics of dehydroxylation of a kaolin clay in presence of ETP sludge. Nonisothermal methods are applied to obtain the thermal curves. Nine solid-state mechanisms are applied for analysing the data obtained in the temperature range of 450–750 °C. Random nucleation is the major process of decomposition in both the clay and clay–sludge mixture at the lower temperature range (450–600 °C). At higher temperatures (600–750 °C), the thermal decomposition of the sludge follows a three-dimensional diffusion process and occurs at the phase boundary with spherical symmetry. The thermal decomposition of the clay–sludge mixture, in the temperature range of 600–750 °C, occurs at the phase boundary with cylindrical symmetry. The kinetic parameters follow the kinetic compensation effect.

The physicochemical characteristics of cocalcined kaolin and petroleum effluent treatment plant (ETP) sludge and its effect on the technological and hydration characteristics of cement have been presented. Conductivity measurements indicate that both the sludge ash (SA) and cocalcined kaolin–sludge mixtures in aqueous medium are reactive in nature. The rate of hydration was investigated by determining the combined water (CW) and Ca(OH) 2 content in the hydration products. The hydration products were characterized by FTIR spectrophotometric method and XRD analysis technique. The rates of hydration of cement containing cocalcined kaolin–sludge mixtures are comparatively higher than the others. Blended cements with improved technological properties may be prepared by replacing 20% cement with cocalcined kaolin–sludge mixtures containing up to 30% sludge.

Petroleum effluent treatment plant (ETP) sludge contains hydrocarbons and its ash is pozzolanic in character. The hydrocarbon may be utilized in the calcination of clay. The present communication reports on the hydration behaviour of lime–metakaolin mixtures produced in the presence of the sludge. The hydration products were characterized by using FTIR, TG, DTA and XRD methods. Use of sludge in metakaolin preparation increases the initial hydration rate and enhances the production of C–S–H or C–A–S–H gel.