X-ray structural parameters of some Indian coals

Five Indian coals of different ranks (C% ~ 73.6-92.8) have been demineralized by chemical method. Very slow scan X-ray scattering studies have been performed and coal structural parameters determined by a semi-quantitative method. The present study reveals that coal consists of a semi-crystalline turbostratic structure. Also, the high background of the diffraction profiles clearly shows that coal has amorphous carbon in tis structure. D002 value decreases and fa increases with increase in coal rank. There is a strong linear relationship between C% and volatile matter content with d002 values of coal

A coastal groundwater management model with Indian case study

The complexity of the hydrogeological setup in coastal areas calls for the adoption of scientific groundwater management techniques. Excessive withdrawal of groundwater in coastal zones will lead to depression of the water table, with associated hazards such as putting the well out of use, rendering abstraction uneconomic with increased lift. A sustained regional groundwater drawdown below sea level runs the risk of saline water intrusion, even for confined coastal aquifers. Uncontrolled groundwater development may lead to reversal of the freshwater gradient, thereby resulting in saline water ingress into coastal aquifers. There are, however, several established methodologies to control and minimise the problems associated with groundwater extraction followed by saline water intrusion. This study developed a convenient and easily implementable analytical model for coastal groundwater management aimed at the control of saltwater intrusion. The technique includes withdrawal of coastal freshwater by means of qanat-well structures associated with artificial recharge through rainwater harvesting aided by percolation ponds and recharge wells. The proposed methodology is suitable specifically for not highly urbanised coastal areas with significant annual precipitation, good hydraulic conductivity of the aquifer and a low depth of fresh groundwater. As a case study, the model is applied to a coastal zone of the Purba Medinipur district of West Bengal, India. Adequate quantifications of the efficiency of the methodology are incorporated and relevant conclusions are drawn

Changing profile of GAD and IA-2 antibody positivity in Indian children with recently diagnosed type 1 diabetes mellitus

Introduction. Published literature on type 1 diabetes (T1DM) patients from India suggests that a substantial number of them are negative to GAD 65 and IA-2 an­tibodies. Antibody positivity rates have been linked to dietary and socio-economic factors and more recently, to changes in the enterobiome. Our anecdotal evidence indicated that antibody positivity rates among newly diagnosed T1DM children were rising. In this presen­tation we have formally collated our data on these antibodies, a first, we believe, in the Indian pediatric population. Material and methods. T1DM was diagnosed by stand­ard clinical criteria advocated by American Diabetes Association including in all patients, the presence of diabetic ketoacidosis (DKA). We used plasma blood glucose rather than A1C to diagnose the acute onset of type 1 diabetes in individuals with symptoms of hy­perglycemia. All patients with this diagnosis had GAD (glutamic acid decarboxylase) and IA-2 (insulinoma antigen 2) antibodies measured as a routine procedure from 2007. Data on patients between the ages of 1 and 16 years as on 31st August 2016 were collected for this study. The antibodies were measured by standard RIA kits from the same manufacturer and performed in the endocrinology laboratory of one of the institutions. Results. We included 694 T1DM cases from 2007 till 2016, out of which 296 were antibody positive. A total of 172 were GAD antibody positive, 62 were IA-2 anti­body positive and 90 exhibited dual antibody positivity (GAD positive + IA-2 positive). The chi-square test for trend analysis showed a significant rising trend for IA-2 antibody alone positive (p < 0.001, chi-square for trend = 17.437, df = 1) and either antibody positive percentages (p < 0.001, chi-square for trend = 22.71, df = 1), but not in the GAD antibody positivity (p = 0.059, chi-square for trend = 3.567, df = 1) and in dual antibody positive percentages (p = 0.486, chi-square for trend = 0.485, df = 1) over a period of 9 years i.e. from 2007 to 2016. Conclusion. Antibody positivity rates in recently di­agnosed T1DM children have changed fairly rapidly over the last nine years. This surge in autoimmunity may also be a significant contributing factor towards the recent increased incidence of T1DM in India

A review on conversion of triglycerides to on-specification diesel fuels without additional inputs

Dependence on fossil fuels for global energy supply has continued to generate concerns about climate change and sustainable development. It has motivated the search for carbon-neutral alternative resources for the production of transportation fuels to replace crude oil. Although biodiesels have recently emerged as a close substitute to petrol diesel, their use in compression ignition engines designed to run on petro-diesel fuels are linked to adverse effects on the engines' performance and life span. This informed efforts at upgrading biodiesel or direct conversion of triglycerides to hydrocarbon mixtures that are identical or similar to that of petro-diesel through hydrodeoxygenation. Moreover, it seems that commercial methods for the conversion of triglycerides to diesel fuels depends on inputs (methanol and hydrogen) derived from fossil fuels. However, it will be desirable to do so without inputs from fossil fuels. Hence, reaction paths for direct conversion of triglycerides to on-specification hydrocarbons fuels without hydrogen gas input are discussed and suggested strategies are in cognisance of green chemistry principles

Towards the conversion of carbohydrate biomass feedstocks to biofuels via hydroxylmethylfurfural

This review appraises the chemical conversion processes recently reported for the production of hydroxylmethylfurfural (HMF), a key biorefining intermediate, from carbohydrate biomass feedstocks. Catalytic sites or groups required for the efficient and selective conversion of hexose substrates to HMF are examined. The principle of concerted catalysis was used to rationalise the dehydration of fructose and glucose to HMF in non-aqueous media. A survey of reported reaction routes to diesel-range biofuel intermediates from HMF or furfural is presented and self-condensation reaction routes for linking two or more HMF and furfural units together toward obtaining kerosene and diesel-range biofuel intermediates are highlighted. The reaction routes include: benzoin condensation, condensation of furfuryl alcohols, hetero Diels–Alder reaction and ketonisation reaction. These reaction routes are yet to be exploited despite their potential for obtaining kerosene and diesel-range biofuel intermediates exclusively from furfural or hydroxylmethylfurfural

Discovery of 3,3'-diindolylmethanes as potent antileishmanial agents

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 againstLeishmania 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 compound

Role of acidity for the production of carvacrol from carvone over sulfated zircona

A simple and eco-friendly process for the isomerization of carvone to carvacrol in the presence of SO42-/ZrO2 catalyst has been described. The reaction is conducted without solvent at moderate temperature with reaction times of 1 to 2 h. In most istances, nearly quantitative yield of carvacrol is obtained without any be-products. The total acidity, different acid concentration, zirocona phases and crystallites size were co-related with the catalytic activity. Activation energy is found to be 11.317 kJ/mol using 8% SO42- ions modified zircona. The bulk and surface properties of the prepared catalysts are examined by X-ray powder diffraction, BET surface area and ammonia – TPD

Temperature Programme Reduction (TPR) Studies of Cobalt Phases in Y-alumina Supported Cobalt Catalysts

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

Lower alkanes dehydrogenation: Strategies and reaction routes to corresponding alkenes

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 C2 and C3 alkanes are particularly of interest as alternatives to steam cracking and fluid catalytic cracking for obtaining C2 and C3 alkenes. This review highlights developments in non-oxidative, autothermal and oxidative dehydrogenation of C2 and C3 alkanes.We examine reaction routes to dehydrogenation of lower alkenes, and analyze the C–H activation mechanismof commercial catalysts in order to gain insight into rational design of improved catalysts for C2 and C3 alkane dehydrogenation at lower temperatures