Introduction
In recent years Nano sized materials are playing significant role in science and technology, due to their unique shape, size, peculiar properties and potential applications. Metal nanoparticles show significant electronic (1), chemical (2), optical (3) properties which are different from those of the bulk materials.
Among the several metal nano particles gold (Au) nanoparticles have attracted rigorous consideration for their numerous applications in catalytic(4), sensing(5), imaging(6), diagnostics(7), tunable surface plasmon resonance(8), surface enhanced Raman scattering(9),higherFermipotential(10),electrical(11), magnetic(12),thermal conductivity chemical and bio stability(13) , anti-bacterial activityanti(14) malarial agent(15), optoelocronics(16), Gold nano particles have been wildly used as the platform materials in the field of drug(17) and DNA delivery systems(18).
Most of the available methods for synthesis of gold nano particles by chemical and physical methods involve photo chemical reduction (19), chemical reduction (20), heat vaporization (21) and electro chemical reduction (22). The reagents can be inorganic compounds such as Na/KBH4, Hydrazine, salts of tartrate, organic compound like sodium citrate, ascorbic acid and amino acids which are capable of being oxidized.However it is unavoidable the usage of chemical reagents in the AuNPs which are ecologically injurious and toxic (23).Hence, non ecofriendly nature of the chemical methods has the inherent drawbacks.
Replacement of the chemical synthesis with clean, nontoxic and globally acceptable green chemistry methods (24) are the present day need in the synthesis of AuNPs. Many biological systems such as bacteria, fungi gums and plants can actively redu...
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...cing a drop of aqueous AuNPs dispersion on the copper girds and subsequently evaporating water naturally overnight at ambient condition. The size of the AuNPs was determined by a JEOL 2000 FX-II TEM.
The crystallinity of the AuNPs was studied by XRD (rigaku, miniflex) with Cuka radiation
Catalytic reduction of p-nitrophenol
As a model reaction we selected the reduction of p-nitro phenol to p-aminophenol by NaBH4. The reduction occurred in aqueous solution in a standard quartz cell with a 1cm path length. The reaction process was as follows.1.7 mL of 0.2mM p-nitro phenol was mixed with 1.0mL of 0.015M NaBH4 in the cell for UV-Visible measurements. Immediately colour change occurred light yellow to deep yellow.0.3mL of AuNPs solution was added to the above mixture. The UV-Visible absorption spectra were recorded with a time interval in a scanning range of 200-700nm.
This experiment was conduct to investigate the fluorescent behaviour of Leucophor PAF and to investigate the quenching of QBS with NaCl. It was found that the Leucophor PAF indeed satisfied the characteristic to act as whitening agent. It was also found that the quenching of QBS with NaCl was a diffusion-controlled collision process.
They have a larger surface area in proportion to their volume. This enables them to interact with different types of biological systems and provides a wide variety of possibilities (Nuruzatulifah, Nizam, & Ain, 2015). The nanoparticles can be seen by transmission electron microscopy (TEM). When there is one nanoparticle, it is called a primary particle. When there is more than one, it is called a secondary particle. In order to measure these particles, they need to be suspended in a solution (Pruneanu, Coros & Pogacean, 2015). Dyed nanoparticles or internally fluorescent nanoparticles barely interact with cellular proteins which is what the study requires. They are also quite easy to manipulate. They can be easily internalized into cells and can be programmed to go to specific sites (Wolbeis,
Michael P. Broadribb, C. (2006). Institution of Chemical Engineers . Retrieved July 26, 2010, from IChemE: http://cms.icheme.org/mainwebsite/resources/document/lpb192pg003.pdf
Very recently, the efficient green methodology for the synthesis of substituted 4H-pyrido[1,2-a]pyrimidines 5.7, by utilising 2-aminopyridine, cyclohexane carbaldehyde 5.8 and 2-phenylacetaldehyde 5.9 under admicellar catalysis by sulphur nanoparticles (Scheme
Add aluminum amalgam in to acetic acid with water and mix. Wait for about 3-5 minutes, while solution will turn grey. Then add P2NP solution and wait 5-10 minutes while stormy reaction starts. Let the flask to stay for about 20-25 minutes.
Alkylated phenols and their derivatives are important materials in both organic synthesis and chemical manufacturing. Mono-alkylphenols and di-alkylphenols are used as raw materials for the manufacture of a wide variety of products such as resins, wire enamels, varnishes, printing inks, antioxidants, flame retardants, ultraviolet absorbers, fungicide, petroleum additives and rubber chemicals [1-17]. Friedel–Crafts alkylation of phenol with tert-butyl alcohol (TBA) produces 2-tert-butylphenol (2-TBP), 4-tert-butylphenol (4-TBP), 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP) and tert-butylphenol ether (TBPE), depending on both the catalyst and the reaction conditions. Based on previous researches, it is well known that moderate acid catalysts or high reaction temperature led to carbon alkylated products and TBPE is produced in the presence of weak acidic catalysts as a major product. 2-TBP is the jarless product of alkylation of phenol with TBA owing to the presence of phenolic (–OH) group on the aromatic ring that kinetically favours o-alkylation. However, due to steric hindrance, thermodynamically unfavoured o-isomer (2-TBP) is readily isomerized into less hindered p-isomer (4-TBP), especially in moderate acidic media. If strong acid catalysts are used in the alkylation reaction, 2,4-DTBP is a dominant product [17,18]. 2,4-DTBP is used in the manufacture of its triphosphite and benzotriazole, which are employed as a co-stabilizer for PVC or UV absorbers in polyolefins [12,13]. 2-TBP is an intermediate for pesticides, fragrances and antioxidants [14]. High selectivity toward 4-TBP is favored since this product imparts enhanced properties to the class of metallic detergents (phenates) used in lubricating oil...
... maximum decolorization of 97 and 77% was detected for Solar Blue A and Solar Flavine 5G at and temperature 50ºC and pH 4 respectively. They observed that by increasing incubation time and enzyme units, the % decolourization also enhanced. H2O2 dose of 0.7mM for Salar Flavin 5G and 0.8mM for Solar Blue A was enough for the dye degradation.
Research done by Figueroa et al. (2013) has turned up an advance in the method of non-viral gene delivery utilizing gold nanoparticles (AuNP). In their work they have developed an exceptionally efficient way of transfection by experimentally improving certain desirable traits of the gold nanoparticle polyamidoamine (AuPAMAM) c...
Gold NPs are one of the most popular NP that have been widely used in researches for their inertness, biocompatibility, easy synthesis in different sizes and shapes. Due to their small size, gold NPs are absorbed in blood circulation and they have good permeation in tumor tissue. This is called enhanced permeation and retention effect (EPR). Due to their unique optical properties and high z (z= 79), AuNPs are ideal for hyperthermia and radiation sensitization, respectively.
== § Test tubes X 11 § 0.10 molar dm -3 Copper (II) Sulphate solution § distilled water § egg albumen from 3 eggs. § Syringe X 12 § colorimeter § tripod § 100ml beaker § Bunsen burner § test tube holder § safety glasses § gloves § test tube pen § test tube method = == = =
Azo compounds are those having R-N=N-R΄ functional group, where R and R΄ can be either aryl or alkyl. It is a derivative of Diazene (Diimide) NH=NH, where both the hydrogen replaced by hydrocarbonyl group e.g PhN=NPh (Azobenzene or diphenyldiazene). The N=N is called as azo group. As a consequence of π – delocalization phenyl azo compounds have vivid colour like red, yellow and orange, due to this, it is used as a dye and known as azo dye [3]. Azo compounds have been incorporated into a wide variety of materials and molecular architectures, dendrimers, polymers and molecular glasses. Due to clean and efficient photochemical isomerisation and substantial change in material properties during light irradiation it has been investigated as an active
The main purpose of green nanotechnology has been to develop clean technologies that would minimize potential human and environmental health risk. Also, to encourage replacement of existing products with the clean technologies that is more environmentally friendly. There are many benefits of using green nanotechnologies as the new solution for energy in both their current availability and their current development. Over the new few decades, the highest growth opportunities will come from application of nanomaterials for making better use of existing resources. Nanotechnologies will help reduce weight of carbon emission in transportation utilizing nanocomposite materials that quickly diffuses across the automotive and aerospace industries. Applications of nanotechnologies will result in a global annual savings of 8000 tons of carbon dioxide, which will rise even further to over millions tons by 2020. But, let’s focus on the positive effects of Green Nanotechnology in Solar.
Photocatalysis is a rapidly developing field of research with a high potential for a wide range of industrial applications, which include mineralization of organic pollutants, disinfection of water and air, production of renewable fuels and organic syntheses.
Gold is the “noblest'; of the noble metals (gold, platinum, palladium, and rhodium), so termed because of their inertness, or reluctance to enter into chemical reactions. Gold will not react with common acids but is attacked by a three-to-one mixture of hydrochloric and nitric acids. This combination is called aqua regia because it reacts with the so-called royal metal. Gold will not combine directly with oxygen, but oxides may be formed indirectly. Gold will also combine with the halogens (fluorine, chlorine bromine, and iodine) and with the cyanides.
J. Clayden, N. Greeves, S. Warren, P. Wothers. Organic Chemistry. 8th ed. 2007, Oxford University Press, p. 1186-1191.