Asian Journal of Green Chemistry
Volume:4 Issue: 2, Spring 2020

1-amidoalkyl-2-naphthols were prepared via one-pot multi-component reaction of 2-naphthol, aldehydes, and amides in the presence of nickel nanoparticles as a solid phase acidic catalyst, under solvent-free condition at 100 °C. The recent literature survey reveals that the nano nickel was used as heterogeneous catalyst and received noteworthy attention because of its inexpensive, non-toxic, low corrosion, waste minimization, easy transport and disposal of the catalyst. Short reaction times, high yields, and easy work-up are the advantages of this protocol.

Hippuric hydrazones 4–8 were prepared starting from treating the corresponding acid with ethanolic HCl forming the corresponding ester 2. The formed ester was then converted to ethyl hippurate 3 by treating the ester with hydrazine hydrate. The formed ethyl hippurate was then irradiated with various substituted aromatic aldehydes under solvent-free conditions forming new series of hippuric hydrazones 4–8. Developing clean synthetic route for synthesizing hippuric hydrazones is the main point of this work which is environmentally and economically desirable. The synthesized compounds were confirmed by spectral NMR, mass, IR and CHN analysis data.

This paper presents an innovative, green and organic electro synthesis in order to prepare Schiff base product by the reduction of 5-methoxy-5,6-bis (3-nitropheyl-4,5-dihydro-1,2,4-triazine-3(2H))-thione followed by the condensation on zinc cathode in aqueous alkaline ethanol media in the presence of salicylaldehyde at room temperature. The main characteristic of this proposal is the electro-reduction and electro-condensation. The bulk electrolysis at constant potential was performed in a three-electrode undivided cell in order to prepare Schiff base. In this sense, good yields and easy purification were achieved. Results indicate that thereduction produced high current in the cell and succeeded a green chemistry process. Products were characterized by IR, NMR (1H, 13C), and SEM.

A novel and green synthesis of 1-phenyl isoquinoline derivatives has been developed using [Ru(p-cymene)Cl2]2, as a homogeneous recyclable catalyst, with Cu(OAc)2 and AgSbF6 as oxidant and additive respectively, in PEG-400 biodegradable and green solvent via C-H/N-N functionalization of 1-(diphenylmethylene) hydrazine and aryl substituted acetylene. This protocol gives a simple extraction procedure, biodegradable and green solvent, high atom economy, reusable catalytic system and wide substrate scope with high yield of the product for the synthesis of isoquinoline derivatives.

In this work, N,N,N',N'-tetramethylethylene-diaminium-N,N'-disulfonic acid chloride {[TMEDSA][Cl]2} has been utilized as a highly effective catalyst in order to promote the following organic transformations under green, solvent-free and mild conditions: (i) the synthesis of 4H-pyrano[2, 3-c]pyrazoles from aromatic aldehydes, 3-methyl-1-phenyl-2-pyrazolin-5-one and malononitrile, (ii) the preparation of α-carbamatoalkyl-β-naphthols from arylaldehydes, β-naphthol and alkyl carbamates, and (iii) the production of α-amidoalkyl-β-naphthols from arylaldehydes, β-naphthol and amides.the formula is not displayed correctly!

An efficient and eco-friendly procedure for the synthesis of 1-amidoalkyl-2-naphthols by the one-pot three-component reaction of various aldehydes, 2-naphthol and acetamide catalyzed by nano-graphene oxide under solvent-free conditions has been described. The presented method has several advantages such as high yields, easy purification, mild reaction conditions, easy work-up, survival of different functional groups, and short reaction times. Moreover, nano-graphene oxide is an easily synthesized, cheap, air and moisture stable, heterogeneous and green catalyst.The catalyst could simply be separated and recovered from the reaction mixture and reused in subsequent reactions without significant loss in activity.

Parabens are compounds often added to cosmetics and pharmaceutics as preservatives for fungi and bacterial growth, but, recent studies have linked these compounds to several adverse side-effects such as cancer, miscarriage and infertility. The extraction of methyl paraben from (hand cream, body lotion, blusher, body cream, and bath foam) was studied using liquid-liquid extraction with ethyl acetate as a solvent, and double beam UV-spectrophotometer at wave length 282 nm. Calibrations are linear (correlation coefficient r>0.997) and the limit of detection was 2.358 μg/mL The concentrations of methyl paraben for the selected cosmetic samples were ranged from 0.077% to 0.451%.

In this work, the cross-linked PPMA-based dental resins scraps were applied to pyrolysis to recover MMA (Methyl methacrylate). Thermal degradation of the cross-linked PPMA-based dental resins scraps was analyzed using TG/DTG to guide the operating condition. The pyrolysis was carried out in a reactor of 143 L, at 345 °C and 1.0 atmosphere. The reaction liquid products which were obtained at 30, 40, 50, 60, 70, 80, and 110 min, were physicochemically characterized for density, kinematic viscosity, and refractive index. The chemical composition of the reaction liquid products, obtained at 30, 40, 50, 60, 70, 80, and 110 min, was determined by GC-MS. The liquid phase yield was 55.50% (wt), while that of the gas phase was 31.69% (wt). The density, kinematic viscosity and refractive index of the reaction liquid products which were obtained at 30, 40, 50, 60, 70, 80, and 110 min, varied between 0.9227 and 0.9380 g/mL, 0.566 and 0.588 mm2/s, and 1.401 and 1.414, respectively. Moreover, it shows the percentage errors at the range of 0.74-2.36%, 7.40-10.86%, and 0.00-0.92%, respectively, as compared to the standard values for density, kinematic viscosity, and refractive index of pure MMA (Methyl metaclylate) at 20 °C. The GC-MS, identified in the reaction liquid products during pyrolysis, esters of carboxylic acids, alcohols, ketones, and aromatics, shows concentrations of MMA (Methyl metaclylate) between 88.003 and 98.975% (Area). The concentrations of MMA (Methyl metaclylate) in the liquid phase, between 30 and 80 min, reach purities above 98% (Area), decreasing drastically with increasing the reaction time after 100 min. Thus, it will be possible to depolymerize the cross-linked PPMA-based dental resins scraps by pyrolysis in order to recover MMA (Methyl methaclylate).

In this study, the adsorption of 3-picrylamino-1,2,4-triazole (PATO) On the surface of fullerene (C60) was evaluated by density functional theory using, Becke, three-parameter and Lee-Yang-Parr (B3LYP). PATO as a green fuel, is such a green material and environmental friendly, because after combustion it produces excessive amounts of N2 gas. Due to the importance of these materials in protecting environmental pollution as well as protecting fossil fuel reserves, it is necessary to research in this field. For this purpose, the structures of PATO, C60, and the PATO-C60 complexes were optimized geometrically. Then, IR and Frontier molecular orbital calculations were performed on them. The calculated energies: Gibbs free energy changes (ΔGad) and adsorption enthalpy changes (ΔHad) revealed that the adsorption process of PATO-C60 complexes are experimentally feasible, spontaneous and exothermic. The specific heat capacity values (CV) showed the heat sensitivity has reduced significantly in the PATO-C60 complexes. The N‒O and C‒N bond lengths and the density values demonstrated that PATO-C60 complexes have higher explosive velocity and blasting pressure in comparison to the pure blasting materials without C60. The Frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied.

Alcohols are selectively oxidized to aldehydes using active manganese dioxide (MnO2) nanoparticles under solvent-free condition using microwave irradiation. The complete conversion of the alcohols to their corresponding aldehydes was achieved successfully within only 15 seconds of irradiation in microwave oven. The products of oxidation were characterized by TLC, IR, and Tollens' test, which showed the characteristic results of the desired aldehydes. This method is found to be fast, green, and a very easy procedure that could be applied for the oxidation of alcohols to aldehydes without further oxidation to carboxylic acids.