Covalently Functionalized Nano-Graphene Oxide for Fine Chemical Synthesis

Nano‐graphene, which is entirely composed of aromatic carbon atoms is relatively a new material, with two dimensional periodic structures and possess amazingly interesting chemical and mechanical properties. Graphene and graphene oxide (GO) materials have been explored widely as supports due to their tunable electrical properties and high surface area as well as different functional groups. The covalent modification of surface oxygen of carbon based materials, like graphene oxide and nano graphene oxide (NGO) with organo amine and other functional groups is very opt for various applications. Covalent immobilization of various organic functional moieties and metal modified organo functionalized species on nano‐graphene oxide surface enables a robust immobilization of the reactive catalytic sites through strong binding on the support surfaces. Such materials prevent the leaching of active metals and improve their recyclability, when used as catalysts in solution phase. As the stability of metal depends also on the functionalization of the NGO support, metal modified/ covalently functionalized nano‐graphene oxide materials are widely used in fine chemical synthesis. The functional group of NGO also prevents the aggregation of the catalytically active metal species during the reaction time. Both amine functionalized and metal (Pd) modified amine functionalized nano graphene oxide exhibit excellent activity towards fine chemical synthesis, such as with multicomponent reactions, oxidation reactions and C‐C coupling reactions

Antioxidant activity of the bioactive compounds from the edible fruits and leaves of Ficus sur Forssk. (Moraceae).

Ficus sur Forssk. (Moraceae) is a medicinal plant species found in Africa and the leaves are used in traditional medicine as a blood builder to boost iron levels for the treatment of anaemia, skin disorders and sexually transmitted diseases. In this study, a phytochemical investigation was conducted on F. sur and the antioxidant properties of the isolates and extracts were evaluated. The major secondary metabolites that were isolated from the fruits and leaves were the triterpenoid (lupeol), sterol (β-sitosterol), phaeophytin (phaeophytin a) and flavonoid (epicatechin). The findings reveal significantly higher (p<0.05) antioxidant activity for the methanol extract of the fruits (IC50 9.06 μg/mL), which may be attributed to the higher phenolic content and presence of epicatechin. The results show the species to be rich in pharmacologically active compounds that are documented to exhibit haematinic effects, stimulate reconstruction and cell proliferation in skin, and inhibit the growth and proliferation of pathogenic agents of sexually transmitted infections. This study therefore validates the ethnomedicinal use of the plant, and its consumption could have a profound influence on nutrition and health, especially amongst indigenous people of Africa.Significance:• In South Africa, the use of indigenous plants for food and medicine, especially by rural populations, has increased due to availability and accessibility.• This study highlights the benefits of the edible fruits of Ficus sur as a nutraceutical.• Ficus sur is shown to contain biomolecules with well-known therapeutic value, which lends scientific credence and validity to its ethnomedicinal use

The effect of synthesis method on the structure, and magnetic and photocatalytic properties of hematite (α-Fe2O3) nanoparticles

Samples of hematite (α-Fe2O3) nanoparticles have been synthesized through the co-precipitation route in cetyltrimethylammoniumbromide (Hem_PR), via a citric acid sol-gel method (Hem_SG) and a modified sol-gel method inTween20 (Hem_TW), and each were annealed at three different temperatures (400, 500 and 600 °C). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission and high-resolution electron microscopy (TEM and HRTEM), Mössbauer spectroscopy and by means of a vibrating sample magnetometer (VSM). In addition, the photocatalytic behaviour of each sample was tested on the degradation of rhodamine B (RhB) in solution. All the characterization techniques showed the formation of phases of pure hematite nanoparticles with improved crystallinity after higher temperature annealing. However, the nanoparticles synthesized in Tween 20 showed the smallest particle size and highest BET surface area, saturation magnetization and photocatalytic activity. Of particular note was the ability of Tween 20 to control the growth of the particles so that grain sizes well below 10 nm were obtained. Thus, Tween 20, when used as a surfactant in the sol-gel route, can serve to improve the physical properties of synthesized hematite nanoparticles.Keywords: Hematite, nanoparticles, Mössbauer spectroscopy, magnetic properties, Tween 20, photocatalysi

Degradation of o-Chloranil Using NanocrystallineCellulose/TiO2 Composites via a Solar Photocatalytic Route

Water pollution by organic pollutants is a continuous and increasing problem of global concern. In this paper, we developed a nanocrystalline cellulose  (NCC) and titania (TiO2 ) based nanocomposite for the photocatalytic degradation of o-chloranil via aqueous wet impregnation. Different NCC loadings  (10, 20, 40, and 80%) were used, and several analytical and microscopy techniques characterised the NCC/TiO2 catalyst. The efficiency of TiO2 as a photo-  catalyst was enhanced through the chiral nematic nature and potential charge carrier capacity of NCC, which lowered the rate of electron  recombination.The NCC/TiO2 material was used in the solar-driven photo-degradation of o-chloranil (3,4,5,6-tetrachloro-1,2-benzoquinone), a by-product  of a commonly used pesticide. The successful decomposition of o-chloranil led to the successful identification of three breakdown products, namely 2,3-  dichloro-4,5-dioxohex-2-enedoic acid (DCA), 2,3-dioxosuccinic acid (DSA) and oxalic acid (OA). The 20% NCC/TiO2 catalyst was found to be optimum and  showed excellent degradation and mineralisation of o-chloranil within 2 hours (~90% degradation after 2 hours or 0.00920 mols of the total 0.0102 mols).  The degradation products were analysed and identified using GC-MS. The photo-catalyst offers many benefits, including ease of preparation, a low cost-  factor, and high stability with no loss of activity

Recent advances in noble metal free doped graphitic carbon nitride based nanohybrids for photocatalysis of organic contaminants in water: A review

Extensive contamination of water bodies by textile dyeing industries, organic pollutants and agricultural waste has emerged water pollution as one of the major global environmental crisis. The effect of this gross negligence is posing serious threats to human health therefore today; conserving water resources for the essence of life is of grave concern. Recently, advancements in photocatalytic properties of graphitic carbon nitride (g-C3N4) for wastewater treatment have gained tremendous interest in research. However, pristine g-C3N4 suffers from bottlenecks such as low surface area, rapid recombination of photo-generated electron–hole pairs and insufficient light absorption which thereby, reduces the photocatalytic degradation activity. Hitherto, noble metals have been widely utilized as dopants but are cost ineffective, rarely found and are difficult to recover. In this updated and all-inclusive review we have briefly discussed photocatalysis mechanism, primarily focused on non-precious elemental doping via various synthesis techniques of noble metal free doped g-C3N4 photocatalysts. Typically metal, non-metal, rare earth metal doping and co-doping have been explored, which demonstrates the synergistic behavior of the doped nanocomposites in modulation of electronic structure, broaden the visible light absorption range, enhancement in photocatalytic wastewater remediation ability to obtain maximum pollutant eradication. Summary remarks conclude the review with valuable knowledge of noble metal free doped g-C3N4 photocatalysts for water purification and sheds light on current challenges and crucial issues associated with its commercialization. The future aspect aims at designing of efficient solar light driven photocatalysts for application in various domains i.e. production of H2 and O2, reduction of CO2, practical use of solar cells, treatment of wastewater, air purification and environmental conservatio

Simple one-pot green method for large-scale production of mesalamine, an anti-inflammatory agent

We report a rapid and efficient synthesis protocol for mesalamine via a green approach with 2-chloro-5-nitrobenzoic acid as the starting material, for its large-scale production. This one-pot method involves the conversion of a chloro group into a hydroxyl group using aqueous KOH solution, followed by the reduction of a nitro group to amine using Pd/C. The product was characterised and confirmed by 1H-nuclear magnetic resonance (NMR), 13C NMR, IR and mass spectrometry techniques. The salient features of the method include excellent conversion (99.3%), high yield (93%), cost effectiveness and validated results for benign, large-scale production

Eco-Friendly Synthesis of Organo-Functionalized Mesoporous Silica for the Condensation Reaction

Amine-functionalised mesoporous silica was prepared by the sonication method, a green approach. The method used aminopropyl trimethoxy silane as the amine source and tetraethyl orthosilicate as a silica source. We distinguished its performance compared to the amine-functionalised mesoporous silica sample prepared by the co-condensation method. The sonication method offered better catalytic activity. The amine-functionalised material was fully characterised by different characterisation techniques such as X-ray diffraction, FTIR, CHN, and SEM. The 12.8% of amine-functionalised material (12.A-MCM-41-S) gave excellent selectivity (98%) and conversion (95%). The activity remained almost unchanged for four cycles

Antioxidant activity of the bioactive compounds from the edible fruits and leaves of Ficus sur Forssk. (Moraceae)

Ficus sur Forssk. (Moraceae) is a medicinal plant species found in Africa and the leaves are used in traditional medicine as a blood builder to boost iron levels for the treatment of anaemia, skin disorders and sexually transmitted diseases. In this study, a phytochemical investigation was conducted on F. sur and the antioxidant properties of the isolates and extracts were evaluated. The major secondary metabolites that were isolated from the fruits and leaves were the triterpenoid (lupeol), sterol (β-sitosterol), phaeophytin (phaeophytin a) and flavonoid (epicatechin). The findings reveal significantly higher (p<0.05) antioxidant activity for the methanol extract of the fruits (IC50 9.06 μg/mL), which may be attributed to the higher phenolic content and presence of epicatechin. The results show the species to be rich in pharmacologically active compounds that are documented to exhibit haematinic effects, stimulate reconstruction and cell proliferation in skin, and inhibit the growth and proliferation of pathogenic agents of sexually transmitted infections. This study therefore validates the ethnomedicinal use of the plant, and its consumption could have a profound influence on nutrition and health, especially amongst indigenous people of Africa. Significance: In South Africa, the use of indigenous plants for food and medicine, especially by rural populations, has increased due to availability and accessibility. This study highlights the benefits of the edible fruits of Ficus suras a nutraceutical. Ficus suris shown to contain biomolecules with well-known therapeutic value, which lends scientific credence and validity to its ethnomedicinal use