Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer

Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1 ), high surface area (90.44 m2 g -1 ) and mesoporous nature of the catalyst effectively promoted the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98 %) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst was investigated up to 5 successive cycles and it showed great stability towards the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields

Widely used catalysts in biodiesel production: a review.

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an eco-friendly alternative to fossil fuel for being renewable, non-toxic, biodegradable, and carbon-neutral. Although the homogeneous catalyst has its own merits, much attention is currently paid toward the chemical synthesis of heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement and easily recovered, thus enhancing reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Furthermore, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area, and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlights the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details

Biosynthesis of Triangular-Shape ZnO Nanoparticles Using Tecoma Stans and Its Antimicrobial Activity

The present work reports the first green synthesis of zinc oxide nanoparticles (ZnO-NPs) using Tecoma stans leaf extract. The ZnO-NPs have been investigated by X-Ray Diffraction (XRD), Ultra Violet-Visible (UV-Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD investigation confirms the crystalline structure of ZnO. The TEM images show triangular shape ZnO-NPs with sizes running from 15-20 nm. The XPS spectrum revealed the presence of Zn and O in the sample. Photoluminescence studies of ZnO-NPs displayed a sharp emission of blue band at 447 nm which is attributed to the defect structures in ZnO crystal. The presence of alcoholic, phenolic amide groups in the plant extracts is responsible for the formation of ZnO-NPs. The synthesized ZnO-NPs showed a very high antibacterial property against five bacterial strains such as Bacillus cereus,Acinetobacter johnsonii, Achromobacter xylosoxidans, Achromobacter spanius and Chromobacterium pseudoviolaceum, with the highest zone of inhibition (ZOI) of 24 mm being shown against Achromobacter spanius strain. Further, the synthesized nanoparticles displayed excellent activities against four fungal strains, where a highest ZOI of 30 mm was observed against Penicillium citirinum, hence proving its high efficacy as antimicrobial agents.</div

Biomass waste-derived catalysts for biodiesel production: Recent advances and key challenges

Biomass-derived catalysts are being intensively studied as potential replacements for traditional chemical catalysts in the sustainable generation of biodiesel because of their unique combination of characteristics; catalytic activity, low-cost, plentiful supply and ecologically friendly and efficient manufacturing procedures. This critical review discusses the recently reported approaches that have been used (mostly since 2016) towards cost-effective and environmentally benign solid base/acid/acid-base catalysts from a range of biomass. Sources include shells, animal bones, and plants. Outlined alongside the push for optimized conversion and yield is the increasing trend for enhanced catalyst reusability and recyclability. Outstanding technical problems associated with catalyst preparation or stability, or waste generation are considered individually. The outlook for solving each of these is discussed, as is the potential of biomass-derived catalysts and the biodiesel they produce to develop the fields of fuel synthesis and energy use. Overall, this review aims to assess the viability of biomass-derived catalysts in the commercial sector and the most promising routes for transferring new technologies from the academic environment to industry

Utilization of Biowaste-derived Catalyst for Biodiesel Production: Process Optimization Using Response Surface Methodology and Particle Swarm Optimization Method

In this experimental and optimization study, banana (Musa acuminata) flower petals ash has been considered as an effective catalyst in the room temperature (28 °C) assisted transesterification to produce biodiesel from waste cooking oil (WCO). The transformation of Musa acuminata flower petals to ash catalyst has been performed by simple conventional open-air burning process. Three important parameters (catalyst concentration, methanol/oil (M/O) molar ratio and time) that play significant role in conversion of WCO to waste cooking methyl ester (WCME) were investigated. In order to maximize the conversion rate these key transesterification parameters were optimized using central composite rotatable design (CCRD) of response surface methodology (RSM). A metaheuristic algorithm popularly known as Particle swarm algorithm (PSO) has been used to observe a clear picture of the global optimum points scattered around the search domain. PSO has also been used to validate the results obtained from CCRD. The chemical composition and morphology of ash catalyst has been investigated using several analytical techniques such as X-Ray Diffraction (XRD), Fourier Transformation Infrared Spectroscopy (FTIR), X-Ray Fluorescence Spectroscopy (XRF), X-ray Photoelectron Spectroscopy (XPS), Thermal Gravimetric Analysis (TGA), Energy Dispersive Spectroscopy (EDS), Brunauer-Emmett-Teller (BET), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Hammett Indicator method. It was observed that the catalyst remained active till 4th reaction cycle. The catalyst’s reusability, renewability and robust activity in the reaction makes it efficient, economic, green and industrially applicable