Asian Journal of Green Chemistry
Volume:7 Issue: 2, Spring 2023

On the basis of reaction rates, chemical equilibrium positions, competitive reaction mechanisms, chemoselectivity, and stereoselectivity, various solvent effects can be categorized. Most organic reactions fall into one of several categories, including dipolar transition state, isopolar transition state, nonpolar transition state, and others, depending on how sensitive to solvents they are. In this instance, kinetic considerations were made for the formation of substituted piperidine 8</strong> from the reaction between 4-methylbenzaldehyde 1</strong>, aniline 2</strong>, and ethyl acetoacetate 3</strong> in the presence of oxalic acid dihydrate at room temperature in both methanol and ethanol media. In addition to being an excellent catalyst, oxalic acid dihydrate is a substance that is kind to the environment. To investigate the kinetics and mechanism of the aforementioned reaction, UV-vis spectrophotometry was used. The data from the experiment indicate that there are two steps in the reaction overall. The reaction was carried out multiple times at various temperatures and the relationship between the overall rate constant, Ln kove</sub></em>, or (Ln kove</sub></em>/T), and the reciprocal temperature was well supported by the Arrhenius and Eyring equations, respectively. This gave the necessary plots to calculate the reaction's parameters (Ea</sub></em>, ΔS</em>ǂ</sup>, ΔH</em>ǂ</sup>, and ΔG</em>ǂ</sup>). Methanol was previously recognized as a desirable solvent in the synthesis of piperidine. However, in a kinetic investigation, ethanol had good effects on accelerating the reaction rate compared with methanol. Ethanol is classified as an environmentally preferable green solvent because it is available by fermenting renewable sources, including sugars, starches, and lingo cellulosics, while, methanol is a toxic alcohol. Herein, we have shown ability of ethanol as a solvent to synthesis of substituted piperidines. The outcomes demonstrated that step k1</sub> is a rate-determining step (RDS) in the reaction mechanism. The obtained results and the steady state approximation supported the proposed mechanism.

Environmental pollution caused by toxic contaminants specially heavy metals is a remarkable issue which directly related to all human activities and mainly has negative effects on human health. Bioremediation is one of the reliable green techniques used for the removal of contaminants form ecosystems. In particular, phytoremediation method is considered as one of the potential approaches for the removal of heavy metals such as the toxic lead metal from environment. We have designed a simple experiment utilized for the removal of lead metal from its solutions. In this phytosorption (biosorption) technique, a dried fava beans powder (Vicia faba</em> L.) was used to take up the lead ions (Pb2+</sup>) from their solutions. It was found that the fava beans biomass have removed up to 96.6% of the lead ions from lead nitrate solutions prepared in different concentrations.

Carbohydrazide and its derivatives are regarded as potential pharmacologically active substances. In particular, they are discussed as important anticancer, antibacterial, anti-inflammatory, anti-tuberculosis, antiviral, as well as antibacterial agents. Owing to their wide-spectrum substantial biological activity, this scaffold has called great attention to assess its skeleton synthetically and biologically. This brief review underlines the various synthetic protocols and the biological properties of carbohydrazide-containing compounds.

In present work, orange peel derived activated carbon (OPAC) loaded into poly (styrene-co-butyl acrylate) green composites were synthesized with different weight fractions of (OPAC) viz.,0, 2, 5, 8, and 10 wt% filler in the biocomposites. </strong>The effect of different water activity (aw</sub>) on the moisture sorption of Orange Peel Activated Carbon (OPAC) filled poly (styrene-co-butyl acrylate) green composites was investigated. Moisture sorption was carried out by exposing the composite specimens to different water activity (aw</sub>) from 0.1 to 0.9 at 25 </strong>°C. The obtained sorption data were used to fit five different sorption isotherm models; namely, Braunauer-Emmet-Teller (BET), Smith, Halsey, Caurie, and Oswin proposed in the literature. The model constants were determined by linear fitting of the sorption equations. The value of the coefficient of determination (R2</sup> = 0.99) confirms the linear fitting of the equations studied.

In this study, L-Proline as an organo-catalyst </strong>has been used for the synthesis of highly functionalized tetrahydropyridines derivatives in good to excellent yields by one-pot multicomponent reaction (MCR) of aniline, methyl acetoacetate, and aromatic aldehydes in ethanol under reflux conditions. The use of green solvents, eco friendliness, mild reaction conditions, and low catalyst loading are advantages of current study.

Electricity generator emission is a silent and rampant epidemic due to its chemical constituents which are known to be toxic and carcinogenic to humans. Reports of death through electricity fume and other environmental pollutants have indeed become almost a daily staple in our country, Nigeria. The unreliable and epileptic power supply by the electric power companies has made many people rely heavily on power-generating sets of all kinds with dire implications. Air quality assessment needs to be carried out in both cities and rural areas to make the environment free from toxic contaminants. This work reviews the electricity generator emission and its impacts on air quality to the environment which has caused a growing number of deaths through inhalation of toxic contaminants from the electricity generator.

The proposed idea in this article is initially to select the best seed layer in terms of spectral properties, and then to place the next nanostructured layers of ZnO on it. If the UV-Visible spectrum of the seed layer is suitable and desirable, the ZnO nanorod layer formed on it will have a better spectral quality. The result </em></strong>of this article shows that the formation of ZnO layer by layer and the selection of the best layer which is obtained by the change in the precursors’ concentration lead to a ZnO thin layer with high absorption range from in infrared to ultraviolet range. In this way, ZnO nanostructures are selected step by step based on UV-Visible spectroscopic properties which were based on the difference in the concentration of precursors and absorption value, and threshold. The study of FESEM image of ZnO thin layer indicates the formation of diagonal nanorods, which have a coral-like appearance with high ratio of length to diameter. XRD studies confirm the growth of diagonal nanorods when concentration of precursors increases. These properties have a good match with high and wide absorption in coral-like ZnO nanostructures.