Search

The catalytic photodegradation of diclofenac, which is a non-steroidal anti-inflammatory drug, from synthetic waste water was investigated under a 254 nm ultra-violet light using MgO nanoparticle as a photocatalyst. The kinetics of the catalytic photodegradation of DF was followed in batch system. It was found that DF degrades to form by-products which are in turn degrades further with slower rates to other by-products and /or CO2 and H2O. The reaction was found to be of consecutive type with the observed pseudo first-order rate constants for the overall catalytic photodegradation (kobs1 = 0.1191, 0.0411, 0.0127 and 0.0052 min−1 for the initial concentrations of DF = 10, 20, 50 and 100 mg L−1). 100% degradation efficiency was obtained in 60 min for 10 mg L−1 DF. The pseudo-first order rate constant for the adsorption (kAds) of DF on 0.1 g MgO-NPs was measured as 0.00762 min−1 and the photolysis rate constant (kp) (0.0069 min−1). [ABSTRACT FROM AUTHOR]

Described herein is an organoborane‐catalysed consecutive borylative reduction of quinolines and isoquinolines to furnish tetrahydro(iso)quinolines bearing a C(sp3)−B bond β to the nitrogen atom. The installed C−B bond is oxidatively transformed to the hydroxy group in one pot. The present double hydroboration is proposed to proceed via a stepwise ionic mechanism involving a boronium ion. The stereo‐outcome was found to be dependent on the position (C2 vs C4) of the substituents in quinolines. [ABSTRACT FROM AUTHOR]

In this study, we developed a strategy for using the Scoggins procedure in the synthesis of acetamidines as novel CO2-triggered switchable surfactants via acetimidates by effectively tuning the chemical equilibrium. The as-synthesized N'-alkyl-N,N-diethylacetamidines exhibit excellent CO2/N2 switchability and their bicarbonate salts have the ability to emulsify oil–water mixtures. [ABSTRACT FROM AUTHOR]

Abstract: The sequential substitution of aqua ligands from [Pt{2‐(phenylthiomethyl)quinoline}(H2O)2]CF3SO3, Pt(L1), [Pt{2‐(4‐tert‐butylphenylthiomethyl)quinoline}(H2O)2]CF3SO3 Pt(L2), and [Pt{2‐(4‐fluorophenylthiomethyl) quinoline}(H2O)2]CF3SO3 Pt(L3) by thiourea nucleophiles (Nu) was studied under pseudo–first‐order conditions as a function of concentration and temperature using stopped‐flow and UV‐visible spectrophotometric techniques. The observed pseudo–first‐order rate constants for the substitutions can be described by the rate law: kobs(1/2) = k2(1/2)[Nu], where the subscript denotes the consecutive substitution steps. The first aqua ligand was substituted opposite to the strong σ‐trans‐directing thioether followed by the aqua ligand opposite to the quinoline or pyridine moieties. Second‐order rate constants, k2(1st), for the substitution of the first aqua ligand by thiourea nucleophiles ranged between 9 and 22 M−1 s−1 for Pt(L1), 86 and 326 M−1 s−1 for Pt(L2), and 58 –287 M−1 s−1 for Pt(L3). The ranges of the second‐order rate constant, k2(2nd), were always lower than the k2(1st)’s and are 0.3‐9 M−1 s‐1 for Pt(L1), 2‐20 M−1 s−1 for Pt(L2), and 0.3‐5 M−1 s−1 for Pt(L3). Aqua substitution from Pt(L2) is slower for both steps than from Pt4, its pyridyl derivative from our previous study. A Job's method of continuous variation plot suggests a species with a metal‐to‐nucleophile ratio of 1:3 as the ultimate product of the chloride substitution from the Pt(II) complexes by the incoming thiourea nucleophiles. The high and negative activation entropy and low and positive activation enthalpy values support an associative mechanism of activation, characteristic of substitution reactions occurring in square‐planar complexes. [ABSTRACT FROM AUTHOR]

Copyright of Chemie Ingenieur Technik (CIT) is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The actual temperature control for consecutive reaction problem is a complex optimization problem. Genetic algorithms (GA) is a metaheuristic inspired by imitating the processes observed during natural evolution. It has a strong global search ability and less computation time, but it exists the premature convergence and poor stability. Ant colony optimization (ACO) is a metaheuristic inspired by imitating the behavior of real ants. It has the robustness and parallel computation, but it exists the slow convergence speed and stagnation phenomenon. In this paper, a new genetic and ant colony self-adaptive hybrid (NGASAH) algorithm based on the chaotic searching strategy, multi-populations and self-adaptive parameter control strategies is presented. In the proposed NGASAH algorithm, the chaotic searching strategy is used to avoid the optimal solution. The strategy of the multiple populations is used to avoid to converge to a local extreme point of all particles. The strategy of self-adaptive parameter control is used to dynamically balance the local search ability and the global ability, and improve the convergence speed. The actual temperature control of consecutive reaction problem is used to test the validity of the NGASAH algorithm. The experiment results show that the NGASAH algorithm can obtain the global search ability and the faster convergence speed in solving the complex optimization problems. [ABSTRACT FROM AUTHOR]

Novel 5-amino-1H-1,2,3-triazoles were synthesized by a new synthetic route that involves consecutive tandem cycloaddition between nitriles and azides [ABSTRACT FROM AUTHOR]

A model of a flow ideal mixing reactor for a consecutive two-stage exothermic first-order reaction was considered. The presence of a region of multiplicity of stationary states was established. This multiplicity region can contain regions of three and five stationary states; the region of five states always appears inside the region of three stationary states. Changes in the type of stationary state stability in each of these regions are analyzed. Numerical calculations of phase trajectories in the regions of stationary state stability and instability were performed. A mechanism of the creation of a stable limiting cycle was suggested for the case of three stationary states. [ABSTRACT FROM AUTHOR]

The reaction between dichloro{l-alkyl-2-(arylazo)imidazole)palladium (II), Pd(N,N')CI2 [N,N'= 1-alkyl-2-(arylazo)imidazole ≡ R'aaiR ≡ p- R'-C6H4-N=N-C3H2N2-1-R; where R' = H (a)/Me (b)/CI (e) and R = Ethyl ≡ Et (1)/Benzyl ≡ Bz (2)] and cytosine (C) has been studied spectrophotometrically in acetonitrile-water (1:1; v/v) medium at 465 nm. The product has been isolated and characterized as [Pd(N,N')C2]CI2 . The kinetics of the nucleophilic substitution reactions has been studied under pseudo-first-order conditions at 298 K. This reaction follows two-step consecutive path (A,→B→C); each step follows first order kinetics with respect to each complex and C and follows the rate laws: Rate - I = k'obs[Pd(N,N')CI2]; k'obs= k'0 + k'2[C]0 and Rate - II = k"obs[[Pd(N,N')(C)CI]+]; k"obs= k"0 + k"2[C]0; with first-step-second-order-rate constant (k'2) greater than second-step-second-order-rate constant (k"2). The rate data supports a nucleophilic association path. External addition of CI (LiCI) suppresses the rate. Increase in π-acidity of the ligand (R'aaiR) increases the rate and follows the order: (i) (b) < (a) < (c) and (ii) (1) < (2). The reactions have been studied at different temperatures (298 - 313 K) and the activation parameters (Δ‡ H° and Δ‡S°) of each step of different reactions were calculated using the Eyring plot. [ABSTRACT FROM AUTHOR]

The kinetical parameters of 1-phenyl-1-hydroxy-2,2,2-trichloro-ethane and 1,1-diphenyl-2,2,2-trichloro-ethane production and the simultaneous sulphonation reaction were determined, taking into account the alteration of the reaction rate constants caused by the dilution of the sulphuric acid catalyst. [ABSTRACT FROM AUTHOR]

Abstract: A highly general, efficient and simple methodology for the regioselective synthesis of aryl tetrazole amines has been explored. The present method involves consecutive desulphurization and C-N cross-coupling reaction. Cheap, readily available and air stable cobalt catalyst has been used for this methodology. In addition, the substrate scope has been demonstrated.Graphical Abstract: A highly general, efficient and simple methodology for the regioselective synthesis of aryl tetrazole amines has been explored. The present method involves consecutive desulphurization and C-N cross-coupling reaction. [ABSTRACT FROM AUTHOR]