Indian Institute of Technology Guwahati

About: Indian Institute of Technology Guwahati is a education organization based out in Guwahati, Assam, India. It is known for research contribution in the topics: Adsorption & Catalysis. The organization has 6933 authors who have published 17102 publications receiving 257351 citations.

Dehydrogenation of n-Alkanes by Solid-Phase Molecular Pincer-Iridium Catalysts. High Yields of α-Olefin Product

Abstract: We report the transfer-dehydrogenation of gas-phase alkanes catalyzed by solid-phase, molecular, pincer-ligated iridium catalysts, using ethylene or propene as hydrogen acceptor. Iridium complexes of sterically unhindered pincer ligands such as iPr4PCP, in the solid phase, are found to give extremely high rates and turnover numbers for n-alkane dehydrogenation, and yields of terminal dehydrogenation product (α-olefin) that are much higher than those previously reported for solution-phase experiments. These results are explained by mechanistic studies and DFT calculations which jointly lead to the conclusion that olefin isomerization, which limits yields of α-olefin from pincer–Ir catalyzed alkane dehydrogenation, proceeds via two mechanistically distinct pathways in the case of (iPr4PCP)Ir. The more conventional pathway involves 2,1-insertion of the α-olefin into an Ir–H bond of (iPr4PCP)IrH2, followed by 3,2-β-H elimination. The use of ethylene as hydrogen acceptor, or high pressures of propene, preclude...

Googling the Guggul (Commiphora and Boswellia) for Prevention of Chronic Diseases

Abstract: Extensive research during last 2 decades has revealed that most drugs discovered today, although costs billions of dollars for discovery, and yet they are highly ineffective in their clinical response. For instance, the European Medicines Agency has approved 68 anti-cancer drugs, and out of which 39 has reached the market level with no indication of increased survival nor betterment of quality of life. Even when drugs did improve survival rate compared to available treatment strategies, most of these were found to be clinically insignificant. This is a fundamental problem with modern drug discovery which is based on thinking that most chronic diseases are caused by alteration of a single gene and thus most therapies are single gene-targeted therapies. However, extensive research has revealed that most chronic diseases are caused by multiple gene products. Although most drugs designed by man are mono-targeted therapies, however, those designed by "mother nature" and have been used for thousands of years, are "multi-targeted" therapies. In this review, we examine two agents that have been around for thousands of years, namely "guggul" from Commiphora and Boswellia. Although we are all familiar with the search engine "google," this is another type of "guggul" that has been used for centuries and being explored for its various biological activities. The current review summarizes the traditional uses, chemistry, in vitro and in vivo biological activities, molecular targets, and clinical trials performed with these agents.

Cross sections for the reactions e+e-→K+K-π+π-, K+K-π0π0, and K+K-K+K- measured using initial-state radiation events

Abstract: We study the processes e^+e^- → K^+K^-π^+π^-γ, K^+K^-π^0π^0 γ, and K^+K^-K^+K^- γ, where the photon is radiated from the initial state. About 84 000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb^(-1) of BABAR data. The invariant mass of the hadronic final state defines the e+e- center-of-mass energy, so that the K^+K^-π^+π^- γ data can be compared with direct measurements of the e^+e^- → K^+K^-π^+π^- reaction. No direct measurements exist for the e^+e^- → K^+K^-π^0π^0 or e^+e^- → K^+K^-K^+K^- reactions, and we present an update of our previous result based on a data sample that is twice as large. Studying the structure of these events, we find contributions from a number of intermediate states and extract their cross sections. In particular, we perform a more detailed study of the e^+e^- → ϕ(1020)ππγ reaction and confirm the presence of the Y(2175) resonance in the ϕ(1020)f_0(980) and K^+K^-f_0(980) modes. In the charmonium region, we observe the J/ψ in all three final states and in several intermediate states, as well as the ψ(2S) in some modes, and measure the corresponding products of branching fraction and electron width.

Optimization of crude distillation system using aspen plus: Effect of binary feed selection on grass-root design

Abstract: With an objective to supplement guidelines available as general rules of thumb for the grass-root design of crude distillation unit (CDU) using binary crude mixtures, this work presents the optimization of crude distillation unit using commercial Aspen Plus software. The crude distillation unit constituted a pre-flash tower (PF), an atmospheric distillation unit (ADU) and a vacuum distillation unit (VDU). Optimization model constituted a rigorous simulation model supplemented with suitable objective functions with and without product flow rate constraints. Three different feed stocks namely Bombay crude, Araby crude and Nigeria crude were considered in this work along with various binary combinations of these crudes. The objective function considered was profit function (subjected to maximization) for cases without product flow rate constraints and raw-materials and energy cost (subjected to minimization) for cases with product flow rate constraints. Parametric study pertaining to feed selection and composition has been conducted in this work to further benefit refinery planning and scheduling. Simulation study inferred that the product flow rate constraints sensitively affect atmospheric distillation column diameter and crude feed flow rate calculations. Based on all simulation studies, a generalized inference confirms that it is difficult to judge upon the quality of the solutions obtained as far as their global optimality is concerned.