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https://www.readbyqxmd.com/read/28214445/immobilization-of-aspergillus-oryzae-%C3%AE-galactosidase-in-an-agarose-matrix-functionalized-by-four-different-methods-and-application-to-the-synthesis-of-lactulose
#1
Cecilia Guerrero, Carlos Vera, Nestor Serna, Andrés Illanes
Aspergillus oryzae β-galactosidase was immobilized in monofunctional glyoxyl-agarose and heterofunctional supports (amino-glyoxyl, carboxy-glyoxyl and chelate-glyoxyl agarose), for obtaining highly active and stable catalysts for lactulose synthesis. Specific activities of the amino-glyoxyl agarose, carboxy-glyoxyl agarose and chelate-glyoxyl agarose derivatives were 3676, 430 and 454IU/g biocatalyst with half-life values at 50°C of 247, 100 and 100h respectively. Specific activities of 3490, 2559 and 1060IU/g were obtained for fine, standard and macro agarose respectively...
February 7, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28214399/magnetite-platinum-nanoparticles-modified-glassy-carbon-electrode-as-electrochemical-detector-for-nitrophenol-isomers
#2
Giles G Gerent, Almir Spinelli
A glassy carbon electrode was modified with magnetite and platinum nanoparticles stabilized with 3-n-propyl-4-picoline silsesquioxane chloride. This chemically-modified electrode is proposed for the first time for the individual or simultaneous electrochemical detection of nitrophenol isomers. Nanoparticles act as catalysts and also increase the surface area. The polymer stabilizes the particles and provides the electrochemical separation of isomers. Under optimized conditions, the reduction peak currents, obtained by differential-pulse voltammetry, of 2-, 3-, and 4-nitrophenol increased linearly with increases in their concentration in the range of 0...
February 9, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28214134/intensification-of-heterogeneously-catalyzed-suzuki-miyaura-cross-coupling-reaction-using-ultrasound-understanding-effect-of-operating-parameters
#3
Sonam V Sancheti, Parag R Gogate
Palladium-catalyzed Suzuki-Miyaura cross-coupling reaction is a significant reaction for obtaining industrially important products. The current research work deals with intensification of reaction of 4-bromoanisole and phenylboronic acid catalyzed with 5wt% Pd/C (5% by weight Pd supported on C available as commercial catalyst) using ultrasound and more importantly, without use of any additional phase transfer catalyst. Heterogeneous catalyst has been selected in the present work so as to harness the benefits of easy separation and the possible limitations of heterogeneous operation are minimized by introducing ultrasonic irradiations...
January 27, 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28213298/electroplating-sludge-derived-zinc-ferrite-catalyst-for-the-efficient-photo-fenton-degradation-of-dye
#4
Zhenbang Cao, Jia Zhang, Jizhi Zhou, Xiuxiu Ruan, Dan Chen, Jianyong Liu, Qiang Liu, Guangren Qian
A zinc-dominant ferrite catalyst for efficient degradation of organic dye was prepared by the calcination of electroplating sludge (ES). Characterizations indicated that zinc ferrite (ZnFe2O4) coexisted with Fe2O3 structure was the predominant phase in the calcined electroplating sludge (CES). CES displayed a high decolorization ratio (88.3%) of methylene blue (MB) in the presence of H2O2 combined with UV irradiation. The high efficiency could be ascribed to the photocatalytic process induced by ZnFe2O4 and the photo-Fenton dye degradation by ferrous content, and a small amount of Al and Mg in the sludge might also contribute to the catalysis...
February 14, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28213150/preparation-of-the-go-pd-nanocomposite-and-its-application-for-the-degradation-of-organic-dyes-in-water
#5
Afshan Omidvar, Babak Jaleh, Mahmoud Nasrollahzadeh
A GO/Pd nanocomposite has been successfully synthesized applying a simple method via immobilizing Pd on the surface of the graphene oxide (GO). The GO/Pd nanocomposite was characterized by X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) spectroscopy, Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. The surface morphology of Pd NPs was viewed by TEM, the particles are spherical with an average particle size of 11nm...
February 9, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28212513/simultaneous-removal-of-no-and-hg-0-over-ce-cu-modified-v2o5-tio2-based-commercial-scr-catalysts
#6
Guilong Chi, Boxiong Shen, Ranran Yu, Chuan He, Xiao Zhang
A series of novel Ce-Cu modified V2O5/TiO2 based commercial SCR catalysts were prepared via ultrasonic-assisted impregnation method for simultaneous removal of NO and elemental mercury (Hg(0)). Nitrogen adsorption, X-ray diffraction (XRD), temperature programmed reduction of H2 (H2-TPR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. 7% Ce-1% Cu/SCR catalyst exhibited the highest NO conversion efficiency (>97%) at 200-400°C, as well as the best Hg(0) oxidation activity (>75%) at 150-350°C among all the catalysts...
February 12, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28212489/direct-single-enzyme-biomineralization-of-catalytically-active-ceria-and-ceria-zirconia-nanocrystals
#7
Christopher D Curran, Li Lu, Yue Jia, Christopher J Kiely, Bryan W Berger, Steven McIntosh
Biomineralization is an intriguing approach to the synthesis of functional inorganic materials for energy applications whereby biological systems are engineered to mineralize inorganic materials and control their structure over multiple length scales under mild reaction conditions. Herein we demonstrate a single enzyme mediated biomineralization route to synthesize crystalline, catalytically active, quantum confined ceria (CeO2-x) and ceria-zirconia (Ce1-yZryO2-x) nanocrystals for application as environmental catalysts...
February 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/28212316/succinimide-formation-from-an-ngr-containing-cyclic-peptide-computational-evidence-for-catalytic-roles-of-phosphate-buffer-and-the-arginine-side-chain
#8
Ryota Kirikoshi, Noriyoshi Manabe, Ohgi Takahashi
The Asn-Gly-Arg (NGR) motif and its deamidation product isoAsp-Gly-Arg (isoDGR) have recently attracted considerable attention as tumor-targeting ligands. Because an NGR-containing peptide and the corresponding isoDGR-containing peptide target different receptors, the spontaneous NGR deamidation can be used in dual targeting strategies. It is well known that the Asn deamidation proceeds via a succinimide derivative. In the present study, we computationally investigated the mechanism of succinimide formation from a cyclic peptide, c[CH₂CO-NGRC]-NH₂, which has recently been shown to undergo rapid deamidation in a phosphate buffer...
February 16, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28212043/cbr4-as-a-halogen-bond-donor-catalyst-for-the-selective-activation-of-benzaldehydes-to-synthesize-%C3%AE-%C3%AE-unsaturated-ketones
#9
Imran Kazi, Somraj Guha, Govindasamy Sekar
CBr4 has been employed as a halogen bond donor catalyst for the selective activation of aldehyde, to achieve an efficient solvent- and metal-free C═C bond forming reaction in the presence of strong acid sensitive groups such as methoxy, cyanide, ester, and ketal for the synthesis of α,β-unsaturated ketones. This unique capability of CBr4 to act as a halogen bond donor has been explored and established using UV-vis as well as IR spectroscopy. Moreover, this unprecedented methodology enables the synthesis of the pharmaceutically important molecule licochalcone A...
February 17, 2017: Organic Letters
https://www.readbyqxmd.com/read/28212042/chiral-calcium-phosphate-catalyzed-asymmetric-alkenylation-reaction-of-arylglyoxals-with-3-vinylindoles
#10
Xiao-Yun Li, Wen-Qiang Yuan, Sheng Tang, Yi-Wei Huang, Jia-Hui Xue, Li Na Fu, Qi-Xiang Guo
A highly efficient alkenylation reaction of arylglyoxals with 3-vinylindoles catalyzed by chiral calcium phosphate is described. Structurally diverse allylic alcohols bearing indole and carbonyl units are prepared in excellent yields, good diastereoselectivities, and high to excellent enantioselectivities. These products are good building blocks for the synthesis of polysubstituted chiral tetrahydrocarbozol-2-ones. The mechanism study indicates that the most likely role of the catalyst is to activate the hydrate of arylglyoxal and control the stereoselectivity via desymmetric coordination...
February 17, 2017: Organic Letters
https://www.readbyqxmd.com/read/28212038/iridium-catalyzed-asymmetric-hydrogenation-of-%C3%AE-%C3%AE-unsaturated-%C3%AE-lactams-scope-and-mechanistic-studies
#11
Qianjia Yuan, Delong Liu, Wanbin Zhang
An efficient asymmetric hydrogenation of β,γ-unsaturated γ-lactams using an iridium-phosphoramidite complex is reported. The chiral γ-lactams were obtained in excellent yields and enantioselectivities (up to 99% yield and 99% ee). The mechanistic studies indicated that the reduced products were obtained via the hydrogenation of the N-acyliminium cations, generated from β,γ-unsaturated γ-lactams, which was verified by (1)H NMR analysis. The reaction was carried out at a reduced catalyst loading of 0.1 mol %, and the reduced products can be transformed to two potential bioactive compounds...
February 17, 2017: Organic Letters
https://www.readbyqxmd.com/read/28212020/a-new-reaction-pathway-induced-by-plasmon-for-selective-benzyl-alcohol-oxidation-on-biocl-possessing-oxygen-vacancies
#12
Hao Li, Feng Qin, Zhiping Yang, Ximin Cui, Jianfang Wang, Lizhi Zhang
Selective organic transformation under mild conditions constitutes a challenge in green chemistry, especially for alcohol oxidation, which typically requires environmentally unfriendly oxidants. Here, we report a new plasmonic catalyst of Au supported on BiOCl containing oxygen vacancies. It photocatalyzes selective benzyl alcohol oxidation with O2 under visible light through synergistic action of plasmonic hot electrons and holes. Oxygen vacancies on BiOCl facilitate the trapping and transfer of plasmonic hot electrons to adsorbed O2, producing •O2(‒) radicals, while plasmonic hot holes remaining on the Au surface mildly oxidize benzyl alcohol to corresponding carbon-centered radicals...
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28212008/correction-to-controlling-first-row-catalysts-amination-of-aryl-and-heteroaryl-chlorides-and-bromides-with-primary-aliphatic-amines-catalyzed-by-a-binap-ligated-single-component-ni-0-complex
#13
Shaozhong Ge, Rebecca A Green, John F Hartwig
No abstract text is available yet for this article.
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28211932/nanostructured-material-based-biofuel-cells-recent-advances-and-future-prospects
#14
REVIEW
Cui-E Zhao, Panpan Gai, Rongbin Song, Ying Chen, Jianrong Zhang, Jun-Jie Zhu
During the past decade, biofuel cells (BFCs) have emerged as an emerging technology on account of their ability to directly generate electricity from biologically renewable catalysts and fuels. Due to the boost in nanotechnology, significant advances have been accomplished in BFCs. Although it is still challenging to promote the performance of BFCs, adopting nanostructured materials for BFC construction has been extensively proposed as an effective and promising strategy to achieve high energy production. In this review, we presented the major novel nanostructured materials applied for BFCs and highlighted the breakthroughs in this field...
February 17, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28211695/synthesis-of-benzoisoselenazolone-derivatives-by-nickel-catalyzed-dehydrogenative-direct-selenation-of-c-sp-2-h-bonds-with-elemental-selenium-in-air
#15
Masayuki Iwasaki, Natsumi Miki, Yuta Tsuchiya, Kiyohiko Nakajima, Yasushi Nishihara
Nickel-catalyzed direct selenation of benzamides bearing an 8-quinolyl auxiliary with elemental selenium provides benzoisoselenazolones in good yield via carbon-selenium and nitrogen-selenium bond formation under aerobic conditions. In addition to aryl C-H bonds, the method can also be applied to alkenyl C-H bonds, constructing an isoselenazolone skeleton. Simple mechanistic analysis shows that the reaction proceeds through a rate-determining C-H bond cleavage. The obtained benzoisoselenazolones are transformed into various organoselenium compounds and utilized as the catalyst for bromolactonization of alkenoic acids...
February 17, 2017: Organic Letters
https://www.readbyqxmd.com/read/28211689/a-stable-porphyrin-based-porous-mog-metal-organic-framework-as-an-efficient-solvent-free-catalyst-for-c-c-bond-formation
#16
Wei Jiang, Jin Yang, Ying-Ying Liu, Shu-Yan Song, Jian-Fang Ma
We herein report the porous 4-fold interpenetrated mog (moganite) metal-organic framework (MOF) [Cd3(tipp)(bpdc)2]·DMA·9H2O (1·Cd; H2tipp = 5,10,15,20-tetrakis(4-(imidazol-1-yl)phenyl)porphyrin, H2bpdc = biphenyl-4,4'-dicarboxylic acid, DMA = N,N'-dimethylacetamide). The incorporation of Cd and carboxylate oxygen affords 1·Cd rich Lewis acid and basic sites. This MOF 1·Cd was then applied as an efficient heterogeneous catalyst for the important cyanosilylation of aldehydes and Knoevenagel condensation reactions...
February 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28211683/the-central-role-of-bicarbonate-in-the-electrochemical-re-duction-of-carbon-dioxide-on-gold
#17
Marco Dunwell, Qi Lu, Jeffrey M Heyes, Jonathan Rosen, Jingguang G Chen, Yushan Yan, Feng Jiao, Bingjun Xu
Much effort has been devoted in the development of efficient catalysts for electrochemical reduction of CO2. Molecular level understanding of electrode-mediated process, particularly the role of bicarbonate in increasing CO2 reduction rates, is still lacking due to the difficulty of directly probing the electrochemical interface. We developed a protocol to observe normally invisible reaction intermediates with a surface enhanced spectroscopy by applying square-wave potential profiles. Further, we demonstrate that bicarbonate, through equilibrium exchange with dissolved CO2, rather than the supplied CO2, is the primary source of carbon in the CO formed at the Au electrode by a combination of in-situ spectroscopic, isotopic labeling, and mass spectroscopic investigations...
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28211670/facile-synthesis-of-unique-hexagonal-nanoplates-of-zn-co-hydroxy-sulfate-for-efficient-electrocatalytic-oxygen-evolution-reaction
#18
Soumen Dutta, Chaiti Ray, Yuichi Negishi, Tarasankar Pal
Cost-effective, highly active water oxidation catalysts are becoming increasingly demanding in the field of energy conversion and storage. Herein, simple modified hydrothermally (MHT) synthesized zinc and cobalt based hydroxyl double salt i.e., Zn4-xCoxSO4(OH)6• 0.5 H2O (ZCS) has been exfoliated for the first time as an efficient electrocatalyst for oxygen evolution reaction (OER) in alkaline medium. Morphology investigation suggests the evolution of unique hexagonal nanoplates of ZCS material. As OER catalyst, it requires only 370 and 450 mV overpotential to achieve 10 and 100 mA cm-2 current density respectively...
February 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28211454/harnessing-catalytic-pumps-for-directional-delivery-of-microparticles-in-microchambers
#19
Sambeeta Das, Oleg E Shklyaev, Alicia Altemose, Henry Shum, Isamar Ortiz-Rivera, Lyanne Valdez, Thomas E Mallouk, Anna C Balazs, Ayusman Sen
The directed transport of microparticles in microfluidic devices is vital for efficient bioassays and fabrication of complex microstructures. There remains, however, a need for methods to propel and steer microscopic cargo that do not require modifying these particles. Using theory and experiments, we show that catalytic surface reactions can be used to deliver microparticle cargo to specified regions in microchambers. Here reagents diffuse from a gel reservoir and react with the catalyst-coated surface. Fluid density gradients due to the spatially varying reagent concentration induce a convective flow, which carries the suspended particles until the reagents are consumed...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28211337/enhanced-electrochemical-degradation-of-ibuprofen-in-aqueous-solution-by-ptru-alloy-catalyst
#20
Chiung-Fen Chang, Tsan-Yao Chen, Ching-Ju Monica Chin, Yu-Tsun Kuo
Electrochemical advanced oxidation processes (EAOPs) regarded as a green technology for aqueous ibuprofen treatment was investigated in this study. Multi-walled carbon nanotubes (MWCNTs), Pt nanoparticles (Pt NPs), and PtRu alloy, of which physicochemical properties were characterized by XRD and X-ray absorption spectroscopy, were used to synthesize three types of cheap and effective anodes based on commercial conductive glass. Furthermore, the operating parameters, such as the current densities, initial concentrations, and solution pH were also investigated...
February 6, 2017: Chemosphere
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