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1.
Over exploitation of natural resources and human activities are relentlessly fueling the emission of CO2 in the atmosphere. Accordingly, continuous efforts are required to find solutions to address the issue of excessive CO2 emission and its potential effects on climate change. It is imperative that the world looks towards a portfolio of carbon mitigation solutions, rather than a single strategy. In this regard, the use of CO2 as a C1 source is an attractive strategy as CO2 has the potential to be a great asset for the industrial sector and consumers across the globe. In particular, the reduction of CO2 offers an alternative to fossil fuels for various organic industrial feedstocks and fuels. Consequently, efficient and scalable approaches for the reduction of CO2 to products such as methane and methanol can generate value from its emissions. Accordingly, in recent years, metal-free catalysis has emerged as a sustainable approach because of the mild reaction conditions by which CO2 can be reduced to various value-added products. The metal-free catalytic reduction of CO2 offers the development of chemical processes with low cost, earth-abundant, non-toxic reagents, and low carbon-footprint. Thus, this perspective aims to present the developments in both the reduction and reductive functionalization chemistry of CO2 during the last decade using various metal-free catalysts.This review article documents the key developments in the metal-free catalytic reduction of CO2 into various energy intensive chemicals and fuels, and reductive functionalization of CO2 for the formation of new C–N bonds. 相似文献
2.
S. Vijay Kumar T. E. Musturappa S. Prasannakumar K. M. Mahadevan 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):1161-1169
Free radical copolymerization of N‐vinyl‐2‐pyrrolidone with 2‐ethoxyethyl methacrylates was carried out with 2,2′‐azobisisobutyronotrile as an initiator in 1,4‐dioxane. The resulting copolymer was characterized by FTIR, H1‐NMR and C13‐NMR spectroscopic techniques thermal properties of copolymer were determined by DSC and TGA. The reactivity ratios of the monomers were computed by the Fineman‐Rose (F‐R), Kelen‐Tudos (K‐T) and extended Kelen‐Tudos (EK‐T) method at lower conversion, using the data obtained from both FTIR and elemental analysis studies; the results are in good agreement with each other. The average reactivity ratio, Alfrey‐Price Q and e values were found to be r 1=0.769, r 2=0.266 and Q 1=0.0859, e 1=0.4508, respectively for NVP/EOEMA copolymer. The distribution of monomer sequence along the copolymer chain was calculated using a statistical method based on obtained reactivity ratio. The number average molecular weight and polydispersity were determined by GPC. 相似文献
3.
Prof. Vladimir I. Bregadze Prof. Igor B. Sivaev Ravindra Dhar Dubey Prof. Andrey Semioshkin Dr. Akim V. Shmal'ko Dr. Irina D. Kosenko Kseniya V. Lebedeva Prof. Swadhin Mandal Prasannakumar Sreejyothi Arindam Sarkar Prof. Zheyu Shen Prof. Aiguo Wu Prof. Narayan S. Hosmane 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(61):13832-13841
A series of boron-containing lipids were prepared by reactions of cyclic oxonium derivatives of polyhedron boranes and metallacarboranes (closo-dodecaborate anion, cobalt and iron bis(dicarbollides)) with amine and carboxylic acids which are derived from cholesterol. Stable liposomal formulations, on the basis of synthesized boron-containing lipids, hydrogenated soybean l -α-phosphatidylcholine and (HSPC) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG) as excipients, were prepared and then characterized by dynamic light scattering (DLS) that revealed the formation of particles to be smaller than 200 nm in diameter. The resulting liposomal formulations showed moderate to excellent loading and entrapment efficiency, thus justifying the design of the compounds to fit in the lipid bilayer and ensuring ease of in vivo use for future application. The liposomal formulations based on cobalt and iron bis(dicarbollide)-based lipids were found to be nontoxic against both human breast normal epithelial cells MCF-10A and human breast cancer cells MCF-7. 相似文献
4.
Simson Prasannakumar Revanasiddappa Manjunatha C. Nethravathi Gurukar Shivappa Suresh Micheal Rajamathi Thimmappa Venkatarangaiah Venkatesha 《Journal of Solid State Electrochemistry》2012,16(10):3189-3199
Through layer-by-layer adsorption (LBL) technique, the positively charged multiwalled carbon nanotubes (MWCNTs) and negatively charged graphene multilayer film were formed on graphite-poly(diallyldimethylammoniumchloride)-polystyrenesulphonate (Gr/PDDA/PSS) modified electrode. Due to large surface area and remarkable electrocatalytic properties of MWCNTs and graphene, the Gr/(PDDA/PSS-[MWCNTs-NH 3 + -graphene-COO?]5) electrode exhibits potent electrocatalytic activity towards the electro-oxidation of nicotinamide adenine dinucleotide (NADH). A substantial decrease in the overpotential was observed at modified electrode, and the electrode showed high sensitivity to the electrocatalytic oxidation of NADH. The modified electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The diffusion coefficient was calculated by chronocoulometry. Chronoamperometric studies showed the linear relationship between oxidation peak current and the concentration of NADH in the range 25–250?μM (R?=?0.999) with the detection limit of 0.1?μM (S/N?=?3). Further, dopamine, uric acid, acetaminophen and hydrogen peroxide do not interfere in the detection of NADH. The ability of MWCNTs and graphene to promote the electron transfer between NADH and the electrode exhibits a promising biocompatible platform for development of dehydrogenase-based amperometric biosensors. Alcohol dehydrogenase (ADH) was casted on Gr/(PDDA/PSS-[MWCNTs-NH 3 + -graphene-COO?]5) electrode; the resulting biosensor showed rapid and high sensitive amperometric response to ethanol with the detection limit of 10?μM (S/N?=?3). 相似文献
5.
V.S. Sivasankarapillai S.S. Das F. Sabir M.A. Sundaramahalingam J.C. Colmenares S. Prasannakumar M. Rajan A. Rahdar G.Z. Kyzas 《Materials Today Chemistry》2021
The route of a specific drug carrier system is always a significant platform of development that combines the principles of biomedical technology, nanotechnology, and pharmaceutical drug design. Transdermal (TD) drug delivery involves the release of the drug via the stratum corneum of the tissue membrane into the sustained release by diffusion across the epidermal layer. This method (often known as topical drug delivery) has increased noteworthy research enthusiasm in the course of recent decades due to its relatively simpler and non-invasive administration. Over the past few decades, considerable advancement was achieved in TD delivery and a number of drugs are now successfully reported. In this review, we focus on the progress regarding applications of important biopolymers described for the TD drug release applications and related aspects. Three mostly reported plant and animal-derived polymers (such as natural rubber, chitosan, and cellulose for the development of TD carrier system) were extensively analyzed. The general principle of TD drug delivery, advantages, and limitations of the works reported were also discussed. 相似文献
6.
M. P. Ajithkumar S. Prasannakumar T. V. Sruthi V. B. Sameer Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2018,55(4):362-368
Synthesis of Poly (N-vinyl pyrrolidone-maleic anhydride-methyl methacrylate) terpolymer using azobisisobutyronitrile in 1,4-dioxan is described. The polymers with different composition were synthesized and characterized using FTIR, 1HNMR, 13NMR, TGA and DSC techniques. The monomer-monomer interactions were studied using Finemann-Ross and Kelen-Tudos methods by calculating the reactivity ratio. The reactivity ratio r1 and r2 with respect to methyl methacrylate and N-vinylpyrrolidone-maleic anhydride complexomer are found to be 6.05 and 0.06 respectively. The study showed methyl methacrylate have higher reactivity than N-vinyl-2-pyrrolidone-maleic anhydride complex, i.e., the terpolymer contained methyl methacrylate in higher ratio. The thermal stability of poly (N-vinyl pyrrolidone-maleic anhydride-methyl methacrylate) was 165°C and the glass transition temperature was found to increase from 153°C to 182°C as MMA concentration increase. The studies indicate the activity of the polymer to inhibit bacterial growth is very poor. 相似文献
7.
B.J. Gireesha C.S. Bagewadi B.C. Prasannakumar 《Communications in Nonlinear Science & Numerical Simulation》2009,14(5):2103-2110
The geometry of laminar flow of an unsteady viscous fluid with uniform distribution of dust particles through a rectangular channel under the influence of pulsatile pressure gradient has been considered. Initially the fluid and dust particles are at rest. The analytical expressions for velocities of fluid and dust particles is obtained by solving the partial differential equations using variable separable method and Laplace transform technique. The skin friction at the boundary plates are also calculated. Finally the changes in the velocity profiles with s and n are shown graphically. 相似文献
8.
M. P. Ajithkumar S. Prasannakumar T. V. Sruth V. B. Sameer Kumar 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(7):480-488
Poly(N-vinyl-2-pyrrolidone-maleic anhydride-styrene) terpolymer was prepared using AIBN initiator with acetone as solvent. The terpolymer was grafted with anti-bacterial agents para-aminobenzoic acid and 2,4-dichlorophenol to introduce bactericidal activity to the terpolymer. The terpolymer and the grafted polymers were characterized by FTIR, 1H-NMR, and 13C-NMR spectroscopic methods. Thermal properties were determined by differential scanning calorimetric technique and thermogravimetric analysis. The glass transition temperature was found to be 111°C (terpolymer), 150°C (VMS-G-PABA) and 130°C (VMS-G-DCP). Terpolymer starts degradation at 288°C and grafted terpolymers at 104°C (VMS-G-PABA) and 129°C (VMS-G-DCP), respectively. The anti-bacterial activity of grafted terpolymers were evaluated by the shake flask method against gram positive and gram negative bacteria E. coli and S. epidermidis. The grafted terpolymers showed effective inhibition against both the bacteria, the minimum inhibition concentration was observed to be 75 µg/mL and 80 µg/mL for VMS-G-PABA and 50 µg/mL for VMS-G-DCP against E. coli and S. epidermidis, respectively. The new polymers showed 90% bacterial growth inhibition at 200 µg/mL. 相似文献
9.
S. Vijay Kumar S. Prasannakumar B. S. Sherigara Boreddy S. R. Reddy Tejraj M. Aminabhavi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):821-827
The copolymers prepared in this study by free radical copolymerization of N-vinylpyrrolidone (M 2) with 4-vinylbenzylchloride (M 1) using 2,2′-azobisisobutyronotrile (AIBN) initiator in 1,4-dioxane solvent at 70°C were characterized by FTIR, 1H-NMR and 13C-NMR techniques. Polymer solubility was tested in both polar and nonpolar solvents. The thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). Copolymer compositions were established by H1-NMR spectra, while reactivity ratios of the monomers were computed using the linearization methods viz., Fineman-Ross (FR) (r 1 = 1.67 and r 2 = 0.67), Kelen-Tudos (KT) (r 1 = 1.77 and r 2 = 0.65) and extended Kelen-Tudos (EK-T) (r 1 = 1.72 and r 2 = 0.63) methods at lower conversion. Furthermore, reactivity ratios in nonlinear error-in-variables method (RREVM) also compute the reactivity ratios (r 1 = 1.76 and r 2 = 0.66); these are found to be in good agreement with each other. The distribution of monomer sequence along the copolymer chain was calculated using a statistical method based on the calculated reactivity ratios. 相似文献
10.
P. Sreejyothi Dr. Kalishankar Bhattacharyya Shiv Kumar Dr. Pradip Kumar Hota Prof. Ayan Datta Prof. Swadhin K. Mandal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(45):11656-11662
In recent years, the applications of low-valent main group compounds have gained momentum in the field of catalysis. Owing to the accessibility of two lone pairs of electrons, NHC-stabilised phosphinidenes have been found to be excellent Lewis bases; however, they cannot yet be used as catalysts. Herein, an NHC-stabilised phosphinidene, 1,3-dimethyl-2-(phenylphosphanylidene)-2,3-dihydro-1H imidazole (1), for the activation of CO2 is reported.A closer inspection of the CO2 activation process by DFT calculations along with intrinsic bond orbital analysis shows that phosphinidene is associated with phenylsilane through a noncovalent π-π interaction between two phenyl rings which activates the Si−H bond facilitating hydride transfer to the CO2 molecule. Detailed DFT studies along with spectroscopic experiments were combined to understand the mechanism of CO2 activation and its catalytic reductive functionalisation leading to the formylation of a range of chemically inert primary amides under mild reaction conditions. 相似文献