A Cost-Effective Slag-based Mix Activated with Soda Ash and Hydrated Lime: A Pilot Study

This study investigates the cost-effective binder material of silica fume blended slag mix using industry grade soda ash and hydrated lime as solid activators. The study followed a "just add water" methodology, observing paste rheology and strength development. Microstructural analysis and TGA-DTA studies were conducted to validate the results. A side-by-side comparison was conducted with other mixing procedures. The study found that using pre-mixed analytical grade Na2CO3 in water can cost up to 60% more than using a mixture activated by NaOH pellets. Using industrial-grade chemicals could save 94.5 percent of the budget. For a 10% SF addition and a 10% targeted NaOH content at a w/s ratio of 0.45, the mixes showed the highest strength development and commendable rheology. The mix demonstrated 35.1 MPa after 28 days and 41.33 MPa after 120 days, making it suitable for use as a structural material. The presence of magnesian calcite, magnesite, and hydrotalcite was detected in the XRD analyses. SEM images showed a denser microstructure developed at 28 days. The TG-DT analysis provided insights into phase transitions and bound water associated with hydration products. The higher strength was attributed to calcite transitioning into magnesian calcite and portlandite supplanting CNASH and CSH

Analysis of buried pipelines subjected to reverse fault motion

Presently available simplified analytical methods and semi-empirical methods for the analysis of buried pipelines subjected to fault motion are suitable only for the strike-slip and the normal-slip type fault motions, and cannot be used for the reverse fault crossing case. A simple finite element model, which uses beam elements for the pipeline and discrete nonlinear springs for the soil, has been proposed to analyse buried pipeline subjected to reverse fault motion. The material nonlinearities associated with pipe-material and soil, and geometric nonlinearity associated with large deformations were incorporated in the analysis. Complex reverse fault motion was simulated using suitable constraints between pipe-nodes and ground ends of the soil spring. Results of the parametric study suggest that the pipeline's capacity to accommodate reverse fault offset can be increased significantly by choosing a near-parallel orientation in plan with respect to the fault line. Further improvement in the response of the pipeline is possible by adopting loose backfill, smooth and hard surface coating, and shallow burial depth in the fault crossing region. For normal or near normal orientations, pipeline is expected to fail due to beam buckling at very small fault offsets.by Amit Prashant and Sudhir Kumar Jai

Analysis of buried pipelines subjected to reverse fault motion

Presently available simplified analytical methods and semi-empirical methods for the analysis of buried pipelines subjected to fault motion are suitable only for the strike-slip and the normal-slip type fault motions, and cannot be used for the reverse fault crossing case. A simple finite element model, which uses beam elements for the pipeline and discrete nonlinear springs for the soil, has been proposed to analyse buried pipeline subjected to reverse fault motion. The material nonlinearities associated with pipe-material and soil, and geometric nonlinearity associated with large deformations were incorporated in the analysis. Complex reverse fault motion was simulated using suitable constraints between pipe-nodes and ground ends of the soil spring. Results of the parametric study suggest that the pipeline's capacity to accommodate reverse fault offset can be increased significantly by choosing a near-parallel orientation in plan with respect to the fault line. Further improvement in the response of the pipeline is possible by adopting loose backfill, smooth and hard surface coating, and shallow burial depth in the fault crossing region. For normal or near normal orientations, pipeline is expected to fail due to beam buckling at very small fault offsets.by Amit Prashant and Sudhir Kumar Jai

Oxidative trifluoromethylation of unactivated olefins: an efficient and practical synthesis of α-trifluoromethyl-substituted ketones.

An economical approach to α-CF3-substituted ketones, which are important intermediates in synthetic and medicinal chemistry, employs olefins and the readily available Langlois reagent (CF3SO 2Na). The reaction is operationally simple, proceeds at room temperature, and exhibits an excellent tolerance toward a wide variety of functional groups. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst

A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)2. A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger

Palladium-Catalyzed Aryl C–H Olefination with Unactivated, Aliphatic Alkenes

Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki–Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct olefination of aryl carbon–hydrogen (C–H) bonds (Fujiwara–Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C–H bond olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C–H olefination for synthesizing divinylbenzene derivatives

Cu(II) catalysed chemoselective oxidative transformation of thiourea to thioamidoguanidine/2-aminobenzothiazole

2-Haloaryl-sec-alkyl unsymmetrical thioureas (Tu) (halo = –F, –Cl) with a catalytic amount of Cu(II) salt get oxidised in situ to their disulfide intermediates followed by an imine-disulfide rearrangement to give thioamidoguanidino (Tag) moieties at room temperature. During this process Cu(II) gets reduced to Cu(I) and forms a complex with the Tag moiety from which Tag moiety can be isolated upon treatment with ammonia. However, when the same reaction was performed at an elevated temperature with a catalytic quantity of Cu(II) salt, Tu bearing o-halogens (–F, –Cl) gave 2-aminobenzothiazoles via a dehalogenative heteroarylation path and not by the Hugerschoff path involving an electrophilic substitution reaction. For thioureas containing reactive ortho halogens (such as –Br, –I) the reaction proceeds at room temperature giving 2-aminobenzothiazoles via a dehalogenative path requiring a catalytic quantity of Cu(II). No transformation of thiourea (Tu) to Tag was observed with Cu(I) salts suggesting the requirement of an oxidising Cu(II) salt for this oxidative transformation. Mild reaction conditions, environmentally benign reagents and solvent, high yields, tolerance of various functional groups are some of the essential features of this methodology

Palladium-Catalyzed Aryl C–H Olefination with Unactivated, Aliphatic Alkenes

Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki–Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct olefination of aryl carbon–hydrogen (C–H) bonds (Fujiwara–Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C–H bond olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C–H olefination for synthesizing divinylbenzene derivatives

Detailed Mechanistic Studies on Palladium-Catalyzed Selective C–H Olefination with Aliphatic Alkenes: A Significant Influence of Proton Shuttling

Directing group-assisted regioselective C–H olefination with electronically biased olefins is well studied. However, the incorporation of unactivated olefins has remained largely unsuccessful. A proper mechanistic understanding of olefination involving unactivated alkenes is therefore essential for enhancing their usage in future. In this Article, detailed experimental and computational mechanistic studies on palladium catalyzed C–H olefination with unactivated, aliphatic alkenes are described. The isolation of Pd­(II) intermediates is shown to be effective for elucidating the elementary steps involved in catalytic olefination. Reaction rate and order determination, control experiments, isotopic labeling studies, and Hammett analysis have been used to understand the reaction mechanism. The results from these experimental studies implicate β-hydride elimination as the rate-determining step and that a mechanistic switch occurs between cationic and neutral pathway. Computational studies support this interpretation of the experimental evidence and are used to uncover the origins of selectivity