Eco-friendly Synthesis of Some New Benzylidene-iminothiazolyl-pyrazol-3-ol Derivatives via One-Pot Multicomponent Reaction and Evaluation of Antioxidant Activities

In present work, one-pot multicomponent reaction (MCR) route for the synthesis of benzylideneiminothiazolyl- pyrazol-3-ol derivatives (5a-p) by reacting ethyl cyanoacetate (1), substituted benzaldehyde (2a-c), thiosemicarbazide (3) and substituted phenacyl bromide (4a-g). This reaction proceeds by using bleaching earth clay (BEC) (pH 12.5) in PEG-400 as a green reaction media. All the synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral data. The pharmacological investigation of the synthesized compounds suggest that most of them showed good antioxidant activity.

Humic Acids Aggregates as Microheterogeneus Reaction Media: Alkaline Hydrolysis Reactions

The influence of humic aggregates in water solution upon the chemical stability under basic conditions of different substrates has been reviewed. The kinetic behavior of each substrate has been modelized in terms of micellar pseudophase model.

Solvent effect and Activation Parameters: A Kinetic Reaction of Ethyl Caprylate in Water-Acetone Media

The kinetic result of hydrolysis of Ethyl Caprlyate has been investigated at different composition of aqueous-organic solvent with Acetone (30-70% v/v) over the temperature range of 20 to 400c. The calculated result follows second order kinetics and is observed that the rate decreases with increasing proportion of Acetone. This behavior is attributed electrostatic nature that various solvent-solute interaction in reaction media. Linear plots of Logk against water concentration shows that equilibrium shifted from dense form to bulky form. Iso-kinetic temperature has been determined with the help of slopes of (ΔH*) versus (ΔS*). Thermodynamic parameter has been calculated with the help of Wynne-Jones and Eyring equation.

Tandem Synthesis of Ultra-High Molecular Weight Drag Reducing Poly-α-Olefins for Low-Temperature Pipeline Transportation

Ultra-high molecular weight poly-α-olefins are widely used as drag reducing agents (DRAs) for pipeline transportation of oil and refined petroleum products. The synthesis of polyolefin DRAs is based on low-temperature Ziegler–Natta (ZN) polymerization of higher α-olefins. 1-Hexene based DRAs, the most effective at room temperature, typically lose DR activity at low temperatures. The use of 1-hexene copolymers with C8–C12 linear α-olefins appears to offer a solution to the problem of low-temperature drag reducing. The present work aims to develop two-stage synthesis of polyolefin DRAs that is based on selective oligomerization of ethylene in the presence of efficient chromium/aminodiphosphine catalysts (Cr-PNP), followed by polymerization of the olefin mixtures, formed at oligomerization stage, using efficient titanium–magnesium ZN catalyst. We have shown that oligomerization of ethylene in α-olefin reaction media proceeds faster than in saturated hydrocarbons, providing the formation of 1-hexene, 1-octene, and branched C10 and C12 olefins; the composition and the ratio of the reaction products depended on the nature of PNP ligand. Oligomerizates were used in ZN polymerization ‘as is’, without additional treatment. Due to branched character of C10+ hydrocarbons, formed during oligomerization of ethylene, resulting polyolefins demonstrate higher low-temperature DR efficiency at low polymer concentrations (~1 ppm) in comparison with benchmark polymers prepared from the mixtures of linear α-olefins and from pure 1-hexene. We assume that faster solubility and more efficient solvation of the polyolefins, prepared using ‘tandem’ ethylene-based process, represent an advantage of these type polymers over conventional poly(1-hexene) and linear α-olefin-based polymers when used as ‘winter’ DRAs.

Chickpea Leaf Exudates: A Highly Efficient Natural Brønsted Acidic Medium for the Synthesis of Pyran-annulated Heterocycles

: We reported Chickpea leaf exudates (CLE) as a Brønsted acid type naturally available biodegradable, ecofriendly and reusable reaction medium for highly efficient and facile one-pot synthesis of pyran annulated heterocyclic systems like 7-aryl-benzopyrano[4,3-b]benzopyran-6,8-diones, tetrahydrobenzo[b]pyran and dihydropyrano[c]chromenes scaffolds. The analogous products were obtained via tandem Knoevengel-Michael addition and cyclocondensation reaction in ethanol at room temperature with 90-96 % yields in a short reaction time. Moreover, the reaction media containing Bronsted acids can be easily recovered and reused upto five times with a slight decrease in product yields.

Preparation and characterization of graphitic carbon nitride-supported l-arginine as a highly efficient and recyclable catalyst for the one-pot synthesis of condensation reactions

In this work, graphitic carbon nitride-supported l-arginine (g-C3N4@l-arginine) nanocatalyst was synthesized and evaluated using FT-IR, EDX, XRD, TGA, and FESEM analyses. The performance of the prepared nanocatalyst was examined in the synthesis of 1,4-dihydropyridine, 4H-chromene, and 2,3-dihydro quinazoline derivatives. The novel g-C3N4@l-arginine nanocatalyst showed high thermal stability, easy separation from reaction media, the capability to be used in various multicomponent reactions, and acceptable reusability.