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The demand of Rare Earth Elements (REEs) has increased for the development of clean and green technologies. Conventional geological sources of REE are insufficient to overcome the high demand of REE; hence, the secondary resources are being actively explored. Coal ashes (CAs), a potentially hazardous material, is one of the best secondary sources containing high concentration of REE. The present study aims to explore the abundance of REE in coal and coal ash from different Thermal Power Stations (TPS). The mineralogy and surface morphology of all samples have been determined. The coals mostly consist of quartz and kaolinite, whereas CAs predominantly contain quartz and mullite. Both coal and CAs are dominated by LREE elements, followed by MREE and HREE. The outlook coefficient (Cout) is close to “1” and the critical percentage (Cp) is more than 30%. Coal ash from some of the TPS is identified as secondary source for REE. Fractionation study of REE from coal to CA is carried out to understand the feasibility of CA. A Pearson correlation has been plotted for individual REE elements with other parameters to understand the affinity of REE to different phases of CA.

Experiments were undertaken to develop a sustainable, process intensified membrane integrated crystallization technique for the extraction of lactose from cheese whey. The study explored concentrative mode of membrane crystallization and its possible integration with conventional evaporative crystallization. Effects of the membrane module, mass transfer coefficient, nucleation rate, pressure drop and their interdependence were studied through modelling and system design. This was followed by exhaustive experimental investigations and parameter optimization. The effect of antisolvent addition on membrane crystallization was also explored. Following this, the membrane integrated technique was employed for selective lactose recovery from real cheese whey sourced from sweetmeat manufacturers. Competitive lactose crystal yields of 3.8- 4.96 g per 100 ml of cheese whey (from which fat & protein content was isolated) were obtained. The presence of membrane lowered the total crystallization times as compared to evaporative crystallization. Addition of antisolvent reduced crystallization times in the range of 13.5% - 23.1% for membrane integrated & chemical precipitation techniques. In the alcohol series of antisolvent dosing , a progression from methanol to butanol demonstrated enhanced reduction in crystallization. Crossflow NanoFiltration (NF) showed a higher concentration than crossflow UltraFiltration (UF). The membrane integrated crystallization technique successfully demonstrated waste valorization with competitive lactose yields from cheese whey.

This chapter exposes lignocellulose as the most abundant feedstock for hydrocarbon biofuel production. It introduces sugar fermentation biofuels (ethanol, butanol, and acetone) and sugar dehydration molecules (levulinic acid, furfural, and 5-hydroxymethylfurfural) as intermediates to hydrocarbon biofuels. It first highlights the gap in terms of properties between these intermediates and conventional transportation fuels. The chapter then deals with techniques to close the gap through C C bond formation and hydrodeoxygenation. It focuses on functional group transformations for achieving C C bond formation and hydrodeoxygenation. Aldol condensation is a ubiquitous reaction that affords the C C coupling of the intermediates and their derivatives. Reaction conditions for achieving hydrodeoxygenation varied from ambient to severe temperature and pressure depending on the functional groups. The condensed products thus synthesized require varied levels of hydrodeoxygenation before they can be useful as drop-in fuels. The chapter also discusses catalyst selections for achieving hydrodeoxygenation of the condensed molecules.

Coal and coal-based products (by-products), along with other fossil fuels should be used with caution because of their impact on human health and the global climate. In the light of the environmental impact these fossil fuels cause, it's essential to understand the elemental configuration of coal-derived samples and their impact on the ecosystem. Some reports in past have described, geochemical and mineralogical physiognomies of fly-ash and their impact on the environment. However, a comprehensive investigation of various aspects of fly ash like geochemistry, mineralogy, morphology, and toxicological effects has been very sparse and the present study reports the above aspects. The ICP-OES studies confirm the presence of various elements (Al, Ca, Fe, Mg, Na, P, S, Si, and Ti) in the samples. The XRD analysis exposed the presence of minerals like Quartz, H-Hematite, Anatase, Muscovite, and Rutile, in addition to the various phases such as amorphous and crystalline in the fly-ash. Specific samples also possessed Ilmenite which is uncommon in many other samples. Chromium and lead, the well-known heavy metals to cause soil and water pollution in the neighbourhood were found to be existing in higher concentrations in the fly-ash samples, whereas cadmium was found to be the least among the toxic elements found in the samples. The samples were subjected to FE-SEM analysis, which reveals the presence of irregularly shaped minerals and unburnt carbon known to reduce the burning efficiency of coal, especially in power plants. Toxicology studies reported in the work suggested that fly-ash is toxic to the environment at higher concentrations than at lower concentrations.

Acid mine water was treated with fly ash zeolite (FAZ), followed by different active chemicals to know its suitability for crops. Acid mine drainage (AMD) was obtained from Gorbi abandoned opencast mines of Singrauli, Northern Coalfields (NCL), India. The AMD was treated with 20 g/l dosing of fly ash zeolite, followed by different precipitating chemicals, using different doses of Ba(OH)2, BaCO3 and Ca(OH)2. The doses of 1.0 g/l Ba(OH)2, 1.5 g/l BaCO3 and 0.5 g/l Ca(OH)2 were used. The treatment with FAZ, followed by 1.0 g/l of Ba(OH)2, converted the water quality of AMD to the permissible level. The electrical conductivity (EC), percentage of sodium and metals found at the permissible level indicated the suitability of mine water for agriculture use. AMD treated directly with 1.0 g/l of Ba(OH)2 was found unsuitable for agriculture use. The treatment with FAZ and followed by BaCO3 (1.5 g/l) explained that the water quality was not at the permissible level and unsuitable for agriculture use. AMD treated directly with 1.5 g/l of BaCO3 was also found unsuitable for agriculture. The treatment with FAZ, and followed by 0.5 g/l dosing of Ca(OH)2, also showed water quality not at the permissible level. The conductivity, total salt content (as TDS) and sulfate values increased or decreased minimally, and there was an increase in the concentrations of total hardness and calcium hardness in the final treated mine water. The direct dosing with 0.5 g/l of Ca(OH)2 made AMD unsuitable for agriculture use. Treatment with 20 g/l FAZ followed by 1.0 g/l of Ba(OH)2 produced the treated AMD suitable for agriculture use.

Four coal samples from Jharia basin, India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical, petrographic and spatial structure of the organic mass by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques.X-ray parameters of coal like interlayer spacing (d002), crystallite size (Lc), aroamticity (fa), average number of aromatic layers (Nc), and coal rank (I26/I20) have been determined using profile-fitting software. Considerable variation is observed in treated coals in comparison to the demineralized coals. The d002 values of treated coals have increased in both the media showing increase in disordering of organic moieties. A linear relationship has been observed between d002 values with the volatile matter of the coals. Similarly, the d002 values show linear relationship with Cdmf contents for demineralized as well as for the treated coals in both the media. The Lc and Nc values have decreased in treated coals corresponding to demineralized coals. The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity (fa) increases with increase in rank and shows a linear relationship with the vitrinite reflectance. The corresponding I26/I20 values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium.FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals (SMCs) in both the media, the corresponding bands at 1550 – 1490 cm-1 and 1355 – 1315 cm-1 respectively. FTIR study confirms that nitration is the predominant phenomenon, though, oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs. In comparison to raw coals, the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

A series of silica doped alumina (SDA) [Si-Al2O3] having high surface area and narrow pore size distribution are synthesized with varying amount of silica and used as a support material to facilitate incorporation of Co, Mg and Zr into it. These supported Co-Mg-Zr/SDA materials are used as catalysts for selective synthesis of middle distillate through Fischer-Tropsch synthesis (FTS) reaction. Trace quantity (∼0.05 wt %) of ruthenium (Ru) has also been used as a promoter for Co -Mg-Zr/SDA catalyst to improve the reducibility, selectivity towards middle distillate and increasing the catalyst life. The detail characterizations of catalysts indicate that Ru promotion and narrow pore size distribution facilitate CO conversion and middle distillate selectivity. Synthetic syngas of composition (H2 = 28.63%, CO = 14.27%, CO2 = 9.25%, CH4 = 1.0%, and N2 = 46.85%), which may be obtained after coal gasification and H2 enrichment process by water gas shift (WGS) reaction has been used as a reactant for middle distillate synthesis. The role of Ru and silica proportion on Co-Mg-Zr/SDA is investigated through Low Temperature Fischer-Tropsch (LTFT) synthesis at 220 °C temperature and 30 bar pressure. The surface acidity of the Ru/Co-Mg-Zr/SDA catalyst plays an important role for middle distillate selectivity and CO conversion. To determine the durability of catalysts, 300 h continuous experimental run has been conducted at Gas Hourly Space Velocity (GHSV) of 500 h−1. Among the catalysts in the present study, Ru/Co-Mg-Zr/SDA(7.5) catalyst shows highest CO conversion (94.2%) with 85% selectivity of C6-C19 hydrocarbon.

Biochar fuel (CH0.50O0.19N0.06) was prepared from Leucaena leucocephala bark (CH2.80O0.53N0.03) through the slow pyrolysis process adopting design of experiments technique. Modelling and optimization of the slow pyrolysis process was respectively carried out implementing five level central composite design and numerical technique under response surface methodology. Pyrolysis temperature and time were taken as independent parameters while biochar fuel yield, bulk density, higher heating value, energy density and energy yield were chosen as dependent parameters. The optimal pyrolysis temperature and time were estimated to be 367.47 °C and 135.38 min respectively. These optimum values of temperature and time gave biochar yield 47.29%, bulk density 319.73 kg/m3, higher heating value 23.30 MJ/kg, energy density 1.21, and energy yield 56.55%. The developed quadratic models were checked using ANOVA (analysis of variance) technique for their validity and degree of fitness. The high values of ‘Adequate precision’,R2 and its negligible difference with ‘AdjustedR2’ as well as ‘PredictedR2’ for each model indicated that the fitted empirical models can be used for prediction with reasonable precision. The quadratic models revealed strong interaction between pyrolysis temperature and time towards preparation of biochar fuel. It was further observed that desirability of pyrolysis temperature (0.91) is more than pyrolysis time (0.63). Comparison of Van Krevelen diagram of present biochar fuel with several other biochar fuels and coals showed that prepared biochar has better fuel properties in comparison to raw bark.

In the era of sustainable chemistry the development of nanocatalysis has drawn special attention. Here we report the preparation of nanocrystalline, mesoporous cerium-tin oxide solid solutions and tested for selective oxidation of benzyl alcohol, cinnamyl alcohol, 4-methylbenzyl alcohol, 2-octanol, and geraniol using molecular oxygen as an oxidant. Among different mesoporous supports with Ce/Sn compositions (98/2, 95/5, 90/10 and 80/20, the highest activity was found for the Ce-Sn mixed oxide (Ce/Sn = 95/5) supported gold nanoparticles. The microkinetic study shows that there was no mass transfer limitation in three phase catalytic system. The supports and the corresponding gold catalysts were extensively characterized by N2 physisorption, XRD, H2-TPR, NH3-TPD, TEM, XPS, RAMAN and XAFS techniques. The nanocrystalline solid solution of CexSn1-xO2 was detected by XRD analysis. The presence of oxide vacancy was confirmed by XPS and RAMAN studies. The reducibility of Ce-Sn mixed oxide support increased upon gold deposition which was confirmed by H2-TPR techniques. The TPD study indicates the alteration of acid-basic sites of the CeO2 oxide upon incorporation of tin and gold nanoparticles. The cooperative role between the gold species and the ceria-tin support has been observed while correlating the catalytic activity results with the characterization studies.

The present study focuses on the catalytic conversion of syngas (CO + H2) through Fischer–Tropsch (FT) route using two identically prepared 0.1 wt.% palladium promoted Mesoporous Alumina (MA) and SBA–15 supported Co (15 wt.%) catalysts. The Fischer–Tropsch activity is performed in a fixed bed tubular reactor at temperature 220 °C and pressure 30 bar with H2/CO ratio ~2 having Gas Hourly Space Velocity (GHSV) of 500 h−1. Detail characterizations of the catalysts are carried out using different analytical techniques like N2 adsorption-desorption, Temperature-programmed reduction with hydrogen (H2-TPR), Temperature-programmed desorption with NH3 (NH3-TPD), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). The results show that the SBA–15 supported catalyst exhibits higher C6–C12 selectivity (57.5%), and MA supported catalyst facilitates the formation of higher hydrocarbons (C13–C20) having a selectivity of 46.7%. This study attributes the use of both the support materials for the production of liquid hydrocarbons through FT synthesis.

Temperature programmed reduction (TPR) is one of the techniques for obtaining information about phases or bulk species in heterogeneous catalysts. Information from TPR analysis can give insights about phase-support interaction and extent of reduction of the phases at different temperatures. TPR technique is a common tool in the characterisation of cobalt based Fischer-Tropsch (FT) catalysts. However, interpretation of TPR profiles of γ-alumina supported cobalt FT catalysts had been characterised with different views on the nature of phases and reduction processes involved. In this report, we use reduction behaviour of unsupported Co3O4 to gain insight for more explicit analysis of TPR profiles of γ-alumina supported Co3O4 catalysts. The transition Co3O4 → CoO → Co in γ-alumina supported catalysts prepared with wet impregnation with aqueous cobalt nitrate and calcined at temperatures ≤ 350°C gave reduction peaks at 300 to 350°C. Reduction peaks at 500 to 600°C were due to Co-Al mixed oxide phases; most likely Co2AlO4 and probably routes formation of the mixed oxide were also discussed. Consideration of tendency of dissolution of γ-alumina during the impregnation of metal salt is instructive toward achieving higher reducibility of Co3O4 in the design of cobalt based Fischer-Tropsch catalysts. Key words: Temperature programmed reduction (TPR) profile, calcinations, Co3O4, γ-Al2O3, Fischer-Tropsch catalyst.

In the present study, a mesoporous silica (SBA-15) encapsulated TiO2 nanoreactor is used as a support for MnOx and this MnOx/TiO2@SBA-15 acts as a catalyst for the one-pot synthesis of imine by oxidative coupling between benzyl alcohol and aniline in the presence of atmospheric air. To understand the properties, the catalysts were characterized by several analytical techniques, namely, N2 adsorption–desorption isotherm, small angle X-ray scattering (SAXS), wide angle X-ray diffraction, high resolution transmission electron microscopy (HRTEM), H2-temperature programmed reduction (H2-TPR), O2-temperature programmed oxidation (O2-TPO) and NH3-temperature programmed desorption (NH3-TPD). The pore encapsulation process by SBA-15 causes TiO2 to be in a highly dispersed state, and this highly dispersed TiO2 makes maximum contact with the MnOx species as well as the reactant molecules. The reaction was carried out at atmospheric pressure with equimolar amounts of substrates without additives in the presence of atmospheric air. The yield and selectivity of imines vary with the MnOx and TiO2 loading. The 7.5 wt% MnOx loaded TiO2@SBA-15 (5 wt% TiO2) nanoreactor showed the highest catalytic activity. With the increase in weak acid sites and the oxygen activation ability of the prepared catalyst, the conversion and selectivity of the desired product reached 96% and 97%, respectively. The investigation of the reaction mechanism suggests that there is a synergistic effect between highly dispersed TiO2 and MnOx, which improves the reactant conversion and the selectivity of the desired product (N-benzylideneaniline) and also the prepared catalyst shows excellent recyclability up to the 10th cycle. The recyclability and hot filtration study confirms the true heterogeneity of the prepared catalyst during imine synthesis. The heterogeneity of the prepared catalyst, the avoidance of any noble metal and the utilization of air as an oxidizing agent represent an efficient, green reaction pathway for imine synthesis.

Meeting the ever-growing demand of global energy in an eco-friendly manner necessitates the evaluation of coal and its combustion residues. For management of coal combustion and its residues on sustainable basis, characterization of trace elements and polycyclic aromatic hydrocarbons (PAHs) is imperative. The feed coal, fly ash, and bottom ash from a power plant (Unchahar, India) were evaluated. Feed coal is low grade high volatile sub-bituminous. Quartz and kaolinite are the predominant minerals in the coal, whereas quartz, mullite, and anhydrite in the ashes. Si > Al > Fe > Ca are the major elements in coal and it ashes. As compared to coal, most of the elements are enriched in the ashes; especially As, Cu, Ni, Pb, and Zn are highly enriched (enrichment factor > 5.0) in fly ash. Cluster analysis showed that As, Co, and Cd are associated with the ash forming elements like P–Mg–Ca–S; Ni, V, Cu, Pb, Zn, and Cr with Al-silicate minerals. Leaching study revealed that the trace elements are within the permissible limits for industrial effluents. The total PAHs content was much higher in coal (4542 μg kg −1 ) than fly ash (32.4 μg kg −1 ) and bottom ash (10.1 μg kg −1 ). High molecular weight PAHs were predominant in coal and fly ash, low molecular weight PAHs in bottom ash.

The present study demonstrates the effect of zirconium promotion on Fe-Zn-based catalysts to boost the active sites of Fischer-Tropsch (FT) catalysts. The catalysts are also promoted by Cu and Ca and the active sites are examined using Temperature-Programmed Reduction (TPR) with H2 and CO and Temperature-Programmed Desorption (TPD) with NH3 and CO2 . The results are presented as a comparative study between Fe-Zn- and Fe-Zn-Zr-based catalysts. The results show that addition of Zr to Fe-Zn catalysts increases the availability and dispersion of the precursor to the active sites and promotion with Cu and Ca independently and synergistically enhances reduction of Fe-Zn-Zr-based catalysts. The presence of Ca promotes carburisation, while Cu inhibits carburisation. The impact of the Ca and Cu on the surface acidity/basicity is governed by the nature of the interaction between the phases in the catalysts. The extent of reduction reflects the availability and dispersion of the precursor to the active phase, while the extent of carburisation will impact on the selectivity of the catalysts.

Activation of molecular O2 by metal or metal oxide nanoparticles is an area of recent research interest. In this work, for the first time, we report that indium oxide nanoparticles of

A simple and one pot process for the synthesis of flavanones in the presence of SO 4 2 - / ZrO 2 , a reusable, heterogeneous catalyst has been described. The reactions were conducted both with and without solvent (using toluene as solvent) at 140 °C with reaction times of 3–4 h. Under these conditions several examples were found with very good yields (73–87%) and up to 83% selectivity. The catalyst was easily recycled and reused without loss of its catalytic activity. The present synthetic method is a simple, clean and environment friendly alternative for synthesizing substituted flavanones.

Air is a very essential part for the existence of humans and other living organisms. To know the quantum of atmospheric dust fall and their mineral and morphological characteristics, dust samples were collected at monthly intervals from three different sites (commercial, residential, and control) of the Jharia coal mining area, India. Samples were analysed for heavy metals, minerals, and morphological features by ICP-AES, XRD, and SEM respectively. The yearly average dust fall was higher for the commercial site (15.5 t/km2/month) than the residential site (10.7 t/km2/month) of Jharia coal mining area. The dust deposition rate was highest during summer (March–June), followed by winter (October–February) and lowest in the monsoon season (July–September). The elemental fall was higher for Zn followed by Pb > Sr > Cu > V > Cr > Ni > Co. The major minerals in dusts from Jharia mining area were quartz, kaolinite, pyrite, albite, and magnesiohornblende. The SEM-EDS analysis showed the dust in commercial sites has contributions from coal, and soil. In the residential site, soot particles from domestic coal burning; and in control site, soot particles from biomass burning were observed in SEM. Overall the intensity of dust pollution is more in the commercial sites of the coal mining area.

Atom efficient synthesis of various value added products has been focused as an intense research area after Kyoto protocol. Styrene epoxidation is a challenging reaction as styrene epoxide is an important monomer for large number of polymers. It has been found that surface acidity and redox property of the catalyst has a major contribution to the catalytic activity for oxidation reaction. In this study Co-HMS-X catalyst was prepared and characterized by BET surface area and porosity measurement, SAXS, SANS, FESEM, HRTEM, UV–vis spectra, FTIR, 29Si NMR, H2-TPR and NH3-TPD techniques. It is observed that 5 mol% Co-HMS-X showed highest catalytic activity for styrene epoxidation reaction using molecular O2 as an oxidant. Interestingly it is found that among three different dopant (Al, Ga, Tl), the Ga promoted Co-HMS-X catalyst (Si:Co:Ga = 100:5:1.25) showed highest catalytic activity in terms of styrene conversion (100%) and styrene epoxide selectivity (68%). The unusual trend of Al, Ga and Tl towards the activity of Co-HMS-X (5 mol%) catalyst has been discussed from the results obtained in the H2-TPR and NH3-TPD study.

An integrated membrane system for crystallization has been studied experimentally. Performance of two membrane based processes; Osmotic Crystallization (OC) and Ultrafiltration (UF) were compared by using different membrane configurations (flat sheet and hollow fibre). Possibility of reduction in crystallization time by antisolvent addition was also explored. Different process combinations were developed for comparative performance analysis. For macromolecular feeds, it was seen UF see was more viable; though FO was attractive with respective to operation at ambient temperature and pressure. Integrated membrane based antisolvent crystallization did not affect the purity of the crystals as is evident from the X-Ray Diffraction analysis of the obtained crystals. The integrated membrane system showed an energy saving of 33.33% while antisolvent addition decreased energy consumption by 16.7%. Combination of membrane based and antisolvent crystallization further lowered the energy consumption by a whopping 36%. This was accompanied with a proportional reduction of 17% of crystallization time with respect to conventional evaporative crystallization. The competitive flux and energy saving quotient makes the system techno-economically viable.

The synthesis of e-caprolactam, a demanding monomer, through a heterogeneous catalytic pathway has remained a key area of research in the last decade. The Beckmann rearrangement reaction in the vapor phase using a solid acid catalyst was found to be very effective for producing e-caprolactam. It is observed that niobium incorporated into mesoporous silica serves as a good catalyst for the Beckmann rearrangement reaction. Recently developed mesoporous silica, having an ordered honeycomb structure, is very useful as it can lead to effective diffusion of reactants and products for several reactions. In this study, Nb-doped mesoporous HMS-X nanocomposite materials with different Nb loadings were prepared by a one step hydrothermal synthesis and characterized by BET surface area and porosity measurements, wide and small angle XRD, SEM, HR-TEM, elemental mapping, FTIR, 29Si-NMR and NH3-TPD techniques. The activity of the Nb–HMS-X catalyst was evaluated for the vapour phase Beckmann rearrangement reaction. The catalyst characterization study shows that Nb is highly dispersed on the HMS-X matrix at lower Nb loadings. At higher Nb loadings it is present in the extra-framework position as revealed from XRD, HR-TEM and 29Si-NMR studies. The NH3-TPD result shows the presence of acidic sites on the catalyst surface, which are active sites for the Beckmann rearrangement reaction. Using the Nb–HMS-X catalyst (Si/Nb = 13) under vapour-phase reaction conditions [temperature = 350 °C, weight hourly space velocity (WHSV) = 15 h−1, cyclohexanone oxime in benzene, cyclohexanone oxime : benzene weight ratio of 1 : 11] gave 100% cyclohexanone oxime conversion with 100% e-caprolactam selectivity, with a space time yield of 1.4–1.6 × 10−3 mol h−1 gcat−1. The catalyst was highly recyclable up to 9 times without significant loss of catalytic activity.

In this decade intensive research was carried out to prepare mesoporous non-silicious oxide for various application. Development of mesoporous ceria based material has become most important because of its application in catalysis, solar cell and photovoltic cell. The selective aerobic oxidation of primary alcohols through an environment benign route to synthesize aldehydes is of utmost importance. The catalytic role of supported gold nanoparticles for aerobic oxidation reaction has been focused in the era of sustainable chemistry. The unique redox property of ceria is a fascination for developing Au–CeO2 catalyst in many studies on aerobic oxidation reaction. In this work, we have prepared mesoporous manganese doped ceria to examine the change of physicochemical properties due to incorporation of managnese to the ceria lattice. Deposition of gold nanoparticles and Mn-doping on ceria enhanced the redox behaviour of ceria as well as the basic properties. A thorough characterization by BET S.A., XRD, Raman, HRTEM, STEM, H2-TPR, CO2-TPD, XPS, XAFS reveal the distortion of in the doped CeO2 lattice is electronic in nature rather than structural distortion. The catalytic activity of the catalysts demonstrate the promotional role of gold nanoparticle in this study.

Hydrogen is considered as the fuel for next generation and extensive research is being pursued for search of new techniques for hydrogen production from renewable sources. There is a diverse collection of hydrogen production processes at their different stages of development. This review paper analyzes the industrial and emerging hydrogen production technologies. These processes include steam methane reformation, partial oxidation, autothermal reforming, steam iron, plasma reforming, thermochemical water splitting and biological processes. Till date, steam reformation of methane is the most used industrial technique and its efficiency can go up to 85%. It meets up to 50% of total hydrogen consumption in the world. Continuous research is going on to enhance production yield as well as to improve the process economics. Considerable work is going on about sorption enhanced reforming and membrane reactor for this purpose. Partial oxidation and autothermal reforming processes are the other two processes which are also used for industrial. The most sought process is the thermochemical water splitting using sunlight. Several research institutes are engaged in the development of hydrogen production technologies using renewable sources. Plasma reformation and biological processes are intensively worked out throughout the globe. The present article reviews the recent developments in industrial techniques which will lead to enhancement of hydrogen production. The non-conventional techniques are described in this article as emerging techniques, which are the promising approaches for hydrogen production from biomass, an abundant, clean and renewable source.

Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe–Zn-based Fischer–Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe–Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3 → Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe–Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe–Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

An efficient protocol for synthesis of 3,3′-diindolylmethanes using recyclable Fe-pillared interlayered clay (Fe-PILC) catalyst under aqueous medium has been developed. All synthesized 3,3′-diindolylmethanes showed promising antileishmanial activity against Leishmania donovani promastigotes as well as axenic amastigotes. Structure–activity relationship analysis revealed that nitroaryl substituted diindolylmethanes showed potent antileishmanial activity. The 4-nitrophenyl linked 3,3′-diindolylmethane 8g was found to be the most potent antileishmanial analog showing IC50 values of 7.88 and 8.37 μM against both L. donovani promastigotes and amastigotes, respectively. Further, a pharmacophore based QSAR model was established to understand the crucial molecular features of 3,3′-diindolylmethanes essential for potent antileishmanial activity. These compounds also exhibited promising antifungal activity against Cryptococcus neoformans, wherein fluorophenyl substituted 3,3′-diindolylmethanes were found to be most potent antifungal agents. Developed synthetic protocol will be useful for economical and eco-friendly synthesis of potent antileishmanial and antifungal 3,3′-diindolylmethane class of compounds.

The present research work is intended to synthesize a series of substituted 2,3-dihydro-2-phenylquinazolin-4(1H)-ones using clay-supported heteropolyacid as a novel heterogeneous, reusable and inexpensive catalyst. This catalyst afforded excellent yields in very short reaction times that shows high selectivity without affecting other functional groups, such as carbon–carbon double bond and heterocyclic moieties. The catalyst could be recycled at least six times and reused. The synthesis involves cyclo-condensation of anthranilamide with an aldehyde at room temperature in the presence of small amount of the catalyst. No column purification is required and products can be purified by simple crystallization.

Supported gold nanoparticles perform as a potential catalyst for CO oxidation, propylene epoxidation and hydrogenation reactions, while using them for alcohol oxidation reaction in the presence of molecular oxygen is a challenging task. Nanocrystalline ceria supported gold catalysts are suitable candidates for alcohol oxidation reaction under mild condition. In this study, ceria based mixed oxides were prepared by modified sol–gel method using triethanolamine/water mixture where the defect sites were created by doping Sm3+ cation to cerium oxide. The catalysts were characterized by XRD, FT-RAMAN, TPR, TPD, XPS, XAFS, and HRTEM techniques. Strong gold–support interaction facilitates the easy removal of capping oxygen ions present in the Sm3+ doped cerium oxide surface as observed by XPS and TPR studies. The acid–base property of the CeO2 oxide after incorporation of samarium and gold deposition was observed from TPD studies. The Au/Sm-CeO2 catalyst was active for benzyl alcohol oxidation reaction using molecular O2 under mild condition.

In the era of sustainable energy, catalysis using gold nanoparticles has drawn considerable attention from world researchers. Oxidation of benzyl alcohol by molecular O2 is an atom efficient path to synthesize benzaldehyde. Nanocrystalline ceria has been proven as a useful support to disperse gold nanoparticles since last few years, however there are a few reports on mesoporous ceria supported gold nanoparticles. In this work a systematic investigation was carried out to improve the activity of Au/CeO2 catalyst by incorporating Ba2+, Ca2+ and Mg2+ cations into the ceria lattice through a sol–gel procedure. Both the doped ceria and ceria supported gold nanoparticles are characterized by BET S.A, XRD, TEM, SAXS, XPS, TPR, CO2-TPD techniques. BET S.A measurements show the mesoporous oxides where H3 hysteresis loops are found. The decrease in the crystallite size of ceria after doping by metal cations is observed in the XRD measurement. The TEM and HRTEM characterization shows the nanocrystalline particle size around 30–50 nm and gold nanoparticles around 10–15 nm in size. Distribution in the particle size for doped ceria have been obtained using SAXS measurements where narrow distributions of ceria particles are found in the 10–20 nm range. The existence of oxide vacancies and the mixture of Ce3+/Ce4+ oxidation states are observed for doped ceria materials in the XPS investigation. The strong gold-support interaction was also evidenced by XPS characterization where oxidic gold was found on the doped ceria surface. Lowering of the reduction peak in ceria after gold nanoparticle deposition was observed from TPR investigation whereas the change in basic site distribution is observed from CO2 TPD experiment, instigating new insights into the surface properties of the catalysts. The catalytic activities of the catalysts were determined for benzyl alcohol oxidation reactions using molecular O2. The catalytic activity was in the order of Au/Ba–CeO2 > Au/Ca–CeO2 > Au/Mg–CeO2 > Au/CeO2. The synergistic effect of gold nanoparticles and dopant cations to the ceria was explained in this work.

Fischer–Tropsch technology has become a topical issue in the energy industry in recent times. The synthesis of linear hydrocarbon that has high cetane number diesel fuel through the Fischer–Tropsch reaction requires syngas with high H 2 /CO ratio. Nevertheless, the production of syngas from biomass and coal, which have low H 2 /CO ratios or are CO 2 rich may be desirable for environmental and socio-political reasons. Efficient carbon utilization in such H 2 -deficient and CO 2 -rich syngas feeds has not been given the required attention. It is desirable to improve carbon utilization using such syngas feeds in the Fischer–Tropsch synthesis not only for process economy but also for sustainable development. Previous catalyst and process development efforts were directed toward maximising C 5+ selectivity; they are not for achieving high carbon utilization with H 2 -deficient and CO 2 -rich syngas feeds. However, current trends in FTS catalyst design hold the potential of achieving high carbon utilization with wide option of selectivities. Highlights of the current trends in FTS catalyst design are presented and their prospect for achieving high carbon utilization in FTS using H 2 -deficient and CO 2 -rich syngas feeds is discussed.

The treatment of coal with nitric acid in aqueous and non-aqueous media introduces changes in the chemical and spatial structure of the organic mass. Four coals of different rank have been treated with nitric acid in aqueous and glacial acetic acid media for assessing the changes in the structural parameters by the X-ray diffraction (XRD) technique. Slow-scan XRD has been performed for the raw and treated coals, and X-ray structural parameters (d002, Lc, and Nc) and aromaticity (fa) have been determined by profile-fitting software. Considerable variation of the structural parameters has been observed with respect to the raw coals. The d002 values have decreased in aqueous medium but increased in acetic acid medium; however, Lc, Nc, and fa values have increased in aqueous medium but decreased in acetic acid medium. It is also observed that considerable oxidation takes place during nitric acid treatment in aqueous medium, but nitration is the predominant phenomenon in acetic acid medium. Disordering of the coal structure increases in acetic acid medium, but a reverse trend is observed in the aqueous medium. As a result, structurally modified coals (SMCs) are derived as new coal-derived substances. 15 refs., 6 figs., 3 tabs.

Advances in fossil fuel exploration have continued to drive availability of lower alkane feedstocks for the chemical industry. Lower alkanes are potential precursors to the plethora of basic organic chemicals. However, conversion of lower alkanes to valuable chemicals often involves indirect or multi-step reaction routes. Developing direct routes to obtain key organic chemicals from lower alkanes would benefit industry. Dehydrogenation of C 2 and C 3 alkanes are particularly of interest as alternatives to steam cracking and fluid catalytic cracking for obtaining C 2 and C 3 alkenes. This review highlights developments in non-oxidative, autothermal and oxidative dehydrogenation of C 2 and C 3 alkanes. We examine reaction routes to dehydrogenation of lower alkenes, and analyze the C–H activation mechanism of commercial catalysts in order to gain insight into rational design of improved catalysts for C 2 and C 3 alkane dehydrogenation at lower temperatures.

Isolongifolene and various other isolongifolene-based products are commercially important chemicals that find applications in perfumery and fragrance industry. These important commodity chemicals are generally prepared by homogeneous catalyzed reactions of longifolene in liquid phase. In the present study, role of acidity and acid distribution on montmorillonite, pillared interlayered clay and modified pillared clay catalysts have been studied for the first time in vapor phase system for the conversion of longifolene to isolongifolene. The number and strength of acid sites of montmorillonite clay mineral have been modified by steps of synthesis and by cations selection. Reaction of Al- pillared montmorillonite with Ru 3+ yielded a catalyst with significantly higher distribution of weak acid sites while fortification of montmorillonite with Ce 3+ and La 3+ had little effect on total acidity and its distribution. In the present study, an attempt has been made to correlate the activity of the catalysts with total acidity, number and strength of the acid for the conversion of longifolene to isolongifolene. NH 3 TPD determined the concentration and strength of acid sites.

The presence of potentially toxic elements in lignite and coal is a matter of global concern during energy extraction from them. Accordingly, Barsingsar lignite from Rajasthan (India), a newly identified and currently exploited commercial source of energy, was evaluated for the presence of these elements and their fate during its combustion. Mobility of these elements in Barsingsar lignite and its ashes from a power plant (Bikaner-Nagaur region of Thar Desert, India) is presented in this paper. Kaolinite, quartz, and gypsum are the main minerals in lignite. Both the fly ash and bottom ash of lignite belong to class-F with SiO2 > Al2O3 > CaO > MgO. Both the ashes contain quartz, mullite, anhydrite, and albite. As, In, and Sr have higher concentration in the feed than the ashes. Compared to the feed lignite, Ba, Co, U, Cu, Cd, and Ni are enriched (10–5 times) in fly ash and Co, Pb, Li, Ga, Cd, and U in bottom ash (9–5 times). Earth crust–normalization pattern showed enrichment of Ga, U, B, Ag, Cd, and Se in the lignite; Li, Ba, Ga, B, Cu, Ag, Cd, Hg, Pb, and Se, in fly ash; and Li, Sr, Ga, U, B, Cu, Ag, Cd, Pb, and Se in bottom ash. Hg, Ag, Zn, Ni, Ba, and Se are possibly associated with pyrite. Leaching test by toxicity characteristic leaching procedure (TCLP) showed that except B all the elements are within the safe limits prescribed by Indian Standards.

Fischer–Tropsch synthesis (FTS) occupies a key position in the search for alternatives to petroleum for obtaining liquid hydrocarbons. Hydrocarbons can be produced from alternative carbonaceous resources (natural gas, coal, biomass and waste) through FTS and the use of biomass is particularly attractive from a carbon footprint point of view. However, the nature of biomass resources dictates a different exploration approach compared to fossil fuel resources. Compared to coal and natural gas based FTS processes where economics of scale is an advantage, a Biomass-to-Liquid (BTL) plant is more suited for smaller scale operation. Thus, the BTL process economy will benefit from a condensed FTS processes. Moreover, considering the expected role of FTS in regional and global hydrocarbon supply in the near future, it becomes pertinent to strive towards improving the process economy. This requires molecular and process engineering and detailed knowledge of the reaction is a pre-requisite to engineering the reaction at molecular level. Syngas to hydrocarbon involves consecutive steps of CO activation, C–C coupling, hydrogenation and desorption of the hydrocarbon product. Atomic details of the dynamics of these steps are still unclear. Recently, clearer pictures about activation are now available. However, over the course of ninety years since the first report on an FTS, proposed pathway of C–C coupling has come full cycle from oxygenate to nonoxygenate and back to oxygenate intermediates. To this end, we attempted an X-ray of progress made at providing answers to issues in the chemistry of FTS. The review focuses on product distribution, macro kinetics and the mechanism of FTS. We compare FTS with other C–C coupling reactions of CO, identify catalytic entities for controlling product selectivity and finally we offer an outlook on future directions of fundamental research towards resolving the lingering questions on the mechanism of C–C coupling in FTS.

EAU:ENERGIE+AAU; Integration of electricity generation with liquid fuel production is a viable strategy towards maximising coal utilisation and hydrocarbon supply. Herein we report on catalyst design for process intensification and optimisation of electricity and hydrocarbon production from coal. Low temperature Fischer-Tropsch synthesis with Fe-Zn (Zn/Fe ratio 0.25) based catalysts using H-2-deficient syngas feed displayed unprecedented low CO2 selectivity. Promotion of the Fe-Zn with Cu and Ca afforded Fischer-Tropsch product distributions that are typical of high temperature Fischer-Tropsch synthesis. The present report provides foundation for design of iron based catalyst that can compete with cobalt based once in terms of low CO2 selectivity. (C) 2013 Elsevier Ltd. All rights reserved.

A variety of furanoses and pyranoses (14 examples) bearing a bromobenzyl and a terminal alkynyl group undergo the reaction in the presence of a heterogeneous basic alumina-supported palladium catalyst and CuI as co-catalyst to give benzannulated 10- to 13-membered macrocycles containing the carbohydrate moiety.

In the present study, samples of coal fly ash were obtained from seven major Indian thermal power plants. These samples were transformed into fly ash zeolite (FAZ) using hydrothermal activation by treatment with NaOH. All experiments were carried out at 100 degrees C, but with different solid:liquid ratios, different concentrations of alkali and different incubation times. The chemical composition, mineralogy and morphology of the fly ash and FAZ were determined by wet chemical method after Na2CO3 fusion, x-ray diffraction and scanning electron microscopy. The cation exchange capacity of fly ash and FAZ was determined using the ammonium acetate method (IS:2720). The ammonium exchange capacity was determined by the titrimetric method. The experiments demonstrate that zeolite can be synthesized at 100 degrees C using alkali. The cation exchange capacity and ammonium adsorption capacity of FAZ (up to 250 meq/100 g and 22.93 mg NH4+/g respectively) indicate that the FAZ may be potentially useful to reduce heavy metals and other pollutants from contaminated environments. Therefore, zeolitization at low temperature potentially allows waste fly ash to be used in an economically advantageous way.

Fischer–Tropsch synthesis (FTS) occupies a key position in the search for alternatives to petroleum for obtaining liquid hydrocarbons. Hydrocarbons can be produced from alternative carbonaceous resources (natural gas, coal, biomass and waste) through FTS and the use of biomass is particularly attractive from a carbon footprint point of view. However, the nature of biomass resources dictates a different exploration approach compared to fossil fuel resources. Compared to coal and natural gas based FTS processes where economics of scale is an advantage, a Biomass-to-Liquid (BTL) plant is more suited for smaller scale operation. Thus, the BTL process economy will benefit from a condensed FTS processes. Moreover, considering the expected role of FTS in regional and global hydrocarbon supply in the near future, it becomes pertinent to strive towards improving the process economy. This requires molecular and process engineering and detailed knowledge of the reaction is a pre-requisite to engineering the reaction at molecular level. Syngas to hydrocarbon involves consecutive steps of CO activation, C–C coupling, hydrogenation and desorption of the hydrocarbon product. Atomic details of the dynamics of these steps are still unclear. Recently, clearer pictures about activation are now available. However, over the course of ninety years since the first report on an FTS, proposed pathway of C–C coupling has come full cycle from oxygenate to nonoxygenate and back to oxygenate intermediates. To this end, we attempted an X-ray of progress made at providing answers to issues in the chemistry of FTS. The review focuses on product distribution, macro kinetics and the mechanism of FTS. We compare FTS with other C–C coupling reactions of CO, identify catalytic entities for controlling product selectivity and finally we offer an outlook on future directions of fundamental research towards resolving the lingering questions on the mechanism of C–C coupling in FTS.

Stern standards on the quality of hydrocarbon fuels, particularly on sulphur and aromatic content, is one of the major drivers of increasing hydrogen demand by petroleum refineries. The fuel standards are often predicated on reducing environmental pollution. However, most commercial hydrogen production processes are based on non-renewable resources which are associated with high carbon footprints. With increasing demand of hydrogen, the carbon footprint associated with hydrogen production will increase accordingly. Incentives for green hydrogen production technologies will be an impetus toward smooth succession of industrial processes from high to low carbon footprint. It will engender a shortened learning curve and facilitate entry of green reforming technologies into the hydrogen market. This review examines the potential of some emerging reforming technologies for hydrogen production from renewable resources.