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https://www.readbyqxmd.com/read/28110233/biobased-alkylphenols-from-lignins-via-a-two-step-pyrolysis-hydrodeoxygenation-approach
#1
P J de Wild, W J J Huijgen, A Kloekhorst, R K Chowdari, H J Heeres
Five technical lignins (three organosolv, Kraft and soda lignin) were depolymerised to produce monomeric biobased aromatics, particularly alkylphenols, by a new two-stage thermochemical approach consisting of dedicated pyrolysis followed by catalytic hydrodeoxygenation (HDO) of the resulting pyrolysis oils. Pyrolysis yielded a mixture of guaiacols, catechols and, optionally, syringols in addition to alkylphenols. HDO with heterogeneous catalysts (Ru/C, CoMo/alumina, phosphided NiMO/C) effectively directed the product mixture towards alkylphenols by, among others, demethoxylation...
January 10, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28110147/self-photodegradation-of-formaldehyde-under-visible-light-by-solid-wood-modified-via-nanostructured-fe-doped-wo3-accompanied-with-superior-dimensional-stability
#2
Chengmin Sheng, Chao Wang, Hanwei Wang, Chunde Jin, Qingfeng Sun, Song Li
In this paper, solid wood with superior self-photodegradation of formaldehyde (HCHO) under visible-light was realized through a facile method at room temperature. Spherical Fe-doped WO3 nanostructured materials deposited on the wood substrate with diameters ranging from 100 to 150nm were mainly responsible for the self-photodegradation of formaldehyde. Fe-doped WO3 nanostructured materials were strongly adhered to wood surface through electrostatic and hydrogen bonding interactions. Additionally, the dimensional stability and the inherent anisotropic thickness swelling of wood were greatly improved and eliminated, respectively...
January 16, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28110062/metal-free-hybrids-of-graphitic-carbon-nitride-and-nanodiamonds-for-photoelectrochemical-and-photocatalytic-applications
#3
Li Zhou, Huayang Zhang, Xiaochen Guo, Hongqi Sun, Shaomin Liu, Moses O Tade, Shaobin Wang
Graphitic carbon nitride (g-C3N4) has been considered as a metal-free, cost-effective, eco-friendly and efficient catalyst for various photoelectrochemical applications. However, compared to conventional metal-based photocatalysts, its photocatalytic activity is still low because of the low mobility of carriers restricted by the polymer nature. Herein, a series of hybrids of g-C3N4 (GCN) and nanodiamonds (NDs) were synthesized using a solvothermal method. The photoelectrochemical performance and photocatalytic efficiency of the GCN/NDs were investigated by means of the generation of photocurrent and photodegradation of methylene blue (MB) solutions under UV-visible light irradiations...
January 12, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28108075/catalytic-potential-of-selected-metal-ions-for-bioleaching-and-potential-techno-economic-and-environmental-issues-a-critical-review
#4
REVIEW
Ashish Pathak, Liam Morrison, Mark Gerard Healy
Bioleaching is considered to be a low-cost, eco-friendly technique for leaching valuable metals from a variety of matrixes. However, the inherent slow dissolution kinetics and low metal leaching yields have restricted its wider commercial applicability. Recent advancements in bio-hydrometallurgy have suggested that these critical issues can be successfully alleviated through the addition of a catalyst. The catalyzing properties of a variety of metals ions (Ag(+), Hg(++), Bi(+++), Cu(++), Co(++) etc.) during bioleaching have been successfully demonstrated...
January 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28107973/high-precision-measurement-of-silicon-in-naphthas-by-icp-oes-using-isooctane-as-diluent
#5
M F Gazulla, M Rodrigo, M Orduña, M J Ventura, C Andreu
An analytical protocol for the accurate and precise determination of Si in naphthas is presented by using ICP-OES, optimizing from the sample preparation to the measurement conditions, in order to be able to analyze for the first time silicon contents below 100µgkg(-1) in a relatively short time thus being used as a control method. In the petrochemical industry, silicon can be present as a contaminant in different petroleum products such as gasoline, ethanol, or naphthas, forming different silicon compounds during the treatment of these products that are irreversibly adsorbed onto catalyst surfaces decreasing its time life...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107933/graphene-like-carbon-nanosheets-as-a-new-electrode-material-for-electrochemical-determination-of-hydroquinone-and-catechol
#6
Hongmei Jiang, Shuqin Wang, Wenfang Deng, Youming Zhang, Yueming Tan, Qingji Xie, Ming Ma
We report here graphene-like carbon nanosheets (GCN) as a new electrode material for the electrochemical determination of hydroquinone (HQ) and catechol (CC). The GCN were prepared from maltose using ammonia chloride as a blowing agent and cobalt nitrate as a graphitization catalyst precursor. The as-prepared GCN material shows high graphitization degree, abundant porosity, and large specific surface area. Two well-separated anodic peaks for HQ and CC are obtained at GCN modified glassy carbon electrode (GCE) with a peak-to-peak separation of 118mV...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107756/photocatalytic-reduction-of-cs-i-ions-removed-by-combined-maghemite-titania-pva-alginate-beads-from-aqueous-solution
#7
Zohreh Majidnia, Mohamad Ali Fulazzaky
The presence of Cs(I) ions in nuclear wastewater becomes an important issue for the reason of its high toxicity. The development of adsorbent embedded metal-based catalysts that has sufficient adsorption capacity is expected for the removal of Cs(I) ions from contaminated water. This study tested the use of maghemite, titania and combined maghemite-titania polyvinyl alcohol (PVA)-alginate beads as an adsorbent to remove Cs(I) ions from aqueous solution with the variables of pH and initial concentration using batch experiments under sunlight...
January 17, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28107616/superhydrophilic-antireflective-periodic-mesoporous-organosilica-coating-on-flexible-polyimide-substrate-with-strong-abrasion-resistance
#8
Jing Wang, Cong Zhang, Chunming Yang, Ce Zhang, Mengchao Wang, Jing Zhang, Yao Xu
Superhydrophilic antireflective periodic mesoporous organosilica (PMO) coating was prepared on flexible polyimide substrate via solvent-evaporation-induced self-assembly (SEISA) method, in which tetraethoxysilane (TEOS) and a special bridged silsesquioxane were used as reactants. The bridged silsesquioxane, EG-BSQ, was synthesized through the stoichiometric reaction between 3-glycidoxyporpyltrimethoxysilane (GPTMS) and ethylene diamine (EDA) at 60 (○)C with no catalyst. Under the influence of surfactant, TEOS and EG-BSQ co-condensed and enclosed the ordered mesporous in the coating...
January 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28107509/development-of-combining-of-human-bronchial-mucosa-models-with-xposeali%C3%A2-for-exposure-of-air-pollution-nanoparticles
#9
Jie Ji, Anna Hedelin, Maria Malmlöf, Vadim Kessler, Gulaim Seisenbaeva, Per Gerde, Lena Palmberg
BACKGROUND: Exposure to agents via inhalation is of great concerns both in workplace environment and in the daily contact with particles in the ambient air. Reliable human airway exposure systems will most likely replace animal experiment in future toxicity assessment studies of inhaled agents. METHODS: In this study, we successfully established a combination of an exposure system (XposeALI) with 3D models mimicking both healthy and chronic bronchitis-like mucosa by co-culturing human primary bronchial epithelial cells (PBEC) and fibroblast at air-liquid interface (ALI)...
2017: PloS One
https://www.readbyqxmd.com/read/28107003/fast-initiating-ruthenium-based-catalysts-for-improved-activity-in-highly-e-selective-cross-metathesis
#10
Tonia S Ahmed, Robert H Grubbs
Ruthenium-based olefin metathesis catalysts bearing dithiolate ligands have been recently employed to generate olefins with high E-selectivity (>99% E) but have been limited by low to moderate yields. In this report, (1)H NMR studies reveal that a major contributing factor to this low activity is the extremely low initiation rates of these catalysts with trans olefins. Introducing a 2-isopropoxy-3-phenylbenzylidene ligand in place of the conventional 2-isopropoxybenzylidene ligand resulted in catalysts that initiate rapidly under reaction conditions...
January 20, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28106994/enzymatic-halogenation-and-dehalogenation-reactions-pervasive-and-mechanistically-diverse
#11
Vinayak Agarwal, Zachary D Miles, Jaclyn M Winter, Alessandra S Eustáquio, Abrahim A El Gamal, Bradley S Moore
Naturally produced halogenated compounds are ubiquitous across all domains of life where they perform a multitude of biological functions and adopt a diversity of chemical structures. Accordingly, a diverse collection of enzyme catalysts to install and remove halogens from organic scaffolds has evolved in nature. Accounting for the different chemical properties of the four halogen atoms (fluorine, chlorine, bromine, and iodine) and the diversity and chemical reactivity of their organic substrates, enzymes performing biosynthetic and degradative halogenation chemistry utilize numerous mechanistic strategies involving oxidation, reduction, and substitution...
January 20, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28106930/local-proton-source-in-the-electrocatalytic-co2-reduction-by-mn-bpy-r-co-3br-complexes
#12
Carlo Nervi, Federico Franco, Claudio Cometto, Luca Nencini, Claudia Barolo, Fabrizio Sordello, Claudio Minero, Jan Fiedler, Marc Robert, Roberto Gobetto
The electrochemical behavior of fac-[Mn(pdbpy)(CO)3Br] (pdbpy = 4-phenyl-6-(phenyl-2,6-diol)-2,2'-bipyridine), 1, in acetonitrile under Ar and its catalytic performances for CO2 reduction with added water, 2,2',2''-trifluoroethanol (TFE) and phenol are discussed in detail. Preparative-scale electrolysis experiments, carried out at -1.5 V vs. SCE in CO2-saturated acetonitrile solutions, reveal that the process selectivity is extremely sensitive to the acid strength, providing CO and formate in different faradaic yields...
January 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28106927/cationic-au-iii-versus-au-i-catalyst-controlled-divergent-reactivity-of-alkyne-tethered-lactams
#13
Pedro Almendros, Benito Alcaide, Sara Cembellín, Israel Fernández, Teresa Martínez Del Campo
Switchable reactivity through cationic gold-based catalyst control built on the oxidation state, namely cationic Au(III) versus Au(I), has been achieved in the direct functionalization of 2-azetidinone-tethered alkynyl indoles.
January 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28106898/desymmetrization-of-aziridine-with-malononitrile-using-cinchona-alkaloid-amide-zinc-ii-catalysts
#14
Noriyuki Shiomi, Mami Kuroda, Shuichi Nakamura
The catalytic enantioselective desymmetrization of aziridines with malononitrile has been developed. Good yield and enantioselectivity were obtained by using cinchona alkaloid amide/Zn(ii) catalysts. The obtained product can be converted to β-aminoester, β-aminoamide and triamide compounds.
January 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28106897/transition-metal-co-ni-nanoparticles-wrapped-with-carbon-and-their-superior-catalytic-activities-for-the-reversible-hydrogen-storage-of-magnesium-hydride
#15
Xu Huang, Xuezhang Xiao, Wei Zhang, Xiulin Fan, Liuting Zhang, Changjun Cheng, Shouquan Li, Hongwei Ge, Qidong Wang, Lixin Chen
Magnesium hydride (MgH2) exhibits long-term stability and has recently been developed as a safe alternative to store hydrogen in the solid state, due to its high capacity of 7.6 wt% H2 and low cost compared to other metal hydrides. However, the high activation energy and poor kinetics of MgH2 lead to inadequate hydrogen storage properties, resulting in low energy efficiency. Nano-catalysis is deemed to be the most effective strategy in improving the kinetics performance of hydrogen storage materials. In this work, robust and efficient architectures of carbon-wrapped transition metal (Co/C, Ni/C) nanoparticles (8-16 nm) were prepared and used as catalysts in the MgH2 system via ball milling to improve its de/rehydrogenation kinetics...
January 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28106856/green-synthesis-and-characterization-of-palladium-nanoparticles-using-origanum-vulgare-l-extract-and-their-catalytic-activity
#16
Mohammed Rafi Shaik, Zuhur Jameel Qandeel Ali, Mujeeb Khan, Mufsir Kuniyil, Mohamed E Assal, Hamad Z Alkhathlan, Abdulrahman Al-Warthan, Mohammed Rafiq H Siddiqui, Merajuddin Khan, Syed Farooq Adil
The synthesis of Palladium (Pd) nanoparticles by green methods has attracted remarkable attention in recent years because of its superiority above chemical approaches, owing to its low cost and ecological compatibility. In this present work, we describe a facile and environmentally friendly synthesis of Pd nanoparticles (Pd NPs) using an aqueous extract of aerial parts of Origanum vulgare L. (OV) as a bioreductant. This plant is available in many parts of the world as well as in Saudi Arabia and is known to be a rich source of phenolic components, a feature we fruitfully utilized in the synthesis of Pd NPs, using various concentrations of plant extracts...
January 19, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28106801/o-carboxymethyl-chitosan-supported-heterogeneous-palladium-and-ni-catalysts-for-heck-reaction
#17
Dongjun Lv, Mingjie Zhang
Two polymer catalysts (Pd-OCMCS and Ni-OCMCS) with good reusability were synthesized by coordinating Pd and Ni onto O-carboxymethyl chitosan (OCMCS). The chemical structure and thermal stability of prepared catalysts were determined by Fourier transform infrared (FT-IR) spectra, Energy Dispersive Spectrometer (EDS)analysis, X-ray diffraction (XRD), and thermogravimetric analyzer (TG-DTG), and the analysis results showed that the Pd and Ni ions coordinated onto the OCMCS and formed a ligand with the -COOH group, amino groups, and -OH group on the OCMCS, and the EDS and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis results showed that the loading amounts of Pd and Ni were approximately 8...
January 18, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28106794/a-thoroughly-validated-virtual-screening-strategy-for-discovery-of-novel-hdac3-inhibitors
#18
Huabin Hu, Jie Xia, Dongmei Wang, Xiang Simon Wang, Song Wu
Histone deacetylase 3 (HDAC3) has been recently identified as a potential target for the treatment of cancer and other diseases, such as chronic inflammation, neurodegenerative diseases, and diabetes. Virtual screening (VS) is currently a routine technique for hit identification, but its success depends on rational development of VS strategies. To facilitate this process, we applied our previously released benchmarking dataset, i.e., MUBD-HDAC3 to the evaluation of structure-based VS (SBVS) and ligand-based VS (LBVS) combinatorial approaches...
January 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28106388/mechanistic-studies-of-single-step-styrene-production-using-a-rhodium-i-catalyst
#19
Benjamin A Vaughan, Sarah K Khani, J Brannon Gary, James D Kammert, Michael S Webster-Gardiner, Bradley A McKeown, Robert J Davis, Thomas R Cundari, T Brent Gunnoe
The direct and single-step conversion of benzene, ethylene, and a Cu(II) oxidant to styrene using the Rh(I) catalyst ((Fl)DAB)Rh(TFA)(η(2)-C2H4) [(Fl)DAB = N,N'-bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA = trifluoroacetate] has been reported to give quantitative yields (with Cu(II) as the limiting reagent) and selectivity combined with turnover numbers >800. This report details mechanistic studies of this catalytic process using a combined experimental and computational approach. Examining catalysis with the complex ((Fl)DAB)Rh(OAc)(η(2)-C2H4) shows that the reaction rate has a dependence on catalyst concentration between first- and half-order that varies with both temperature and ethylene concentration, a first-order dependence on ethylene concentration with saturation at higher concentrations of ethylene, and a zero-order dependence on the concentration of Cu(II) oxidant...
January 20, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28106382/lactide-as-the-playmaker-of-the-rop-game-theoretical-and-experimental-investigation-of-ring-opening-polymerization-of-lactide-initiated-by-aminonaphtholate-zinc-complexes
#20
Dawid Jędrzkiewicz, Grażyna Adamus, Michał Kwiecień, Łukasz John, Jolanta Ejfler
A family of homo- and heteroleptic zinc complexes bearing aminonaphtholate ligands was synthesized and fully characterized. Using NMR spectroscopy and DFT calculation, bis-alkoxy-bridged complexes [LZn(μ-OR)]2 were confirmed to have dimeric structures in solution, analogous to those obtained via X-ray crystallography. Surprisingly, a detailed experimental and theoretical study of the catalytic activity of [LZn(μ-OR)]2 in the ring-opening polymerization (ROP) of lactides showed that although well-defined alkoxy dimers possess a single-site structural motif, the most active initiator is obtained during in situ alcoholysis of the alkylzinc precursor...
January 20, 2017: Inorganic Chemistry
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