Solvation of Dimethyl Succinate in a Sodium Hydroxide Aqueous Solution. A Computational Study

2009 ◽  
Vol 113 (18) ◽  
pp. 6473-6477 ◽  
Author(s):  
Xiuquan Sun ◽  
Tsun-mei Chang ◽  
Yang Cao ◽  
Satomi Niwayama ◽  
William L. Hase ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sodium Hydroxide ◽  
Computational Study ◽  
Dimethyl Succinate

2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Atom Abstraction ◽  
Oh Radical ◽  
Free Energies ◽  
Intramolecular Hydrogen ◽  
Solvation Free Energies ◽  
Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

Modification of activated carbon using sodium acetate and its regeneration using sodium hydroxide for the adsorption of copper from aqueous solution

Carbon ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 1081-1084 ◽  
Author(s):  
Dan Mugisidi ◽  
Aria Ranaldo ◽  
Johny W. Soedarsono ◽  
Muhammad Hikam
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Sodium Hydroxide ◽  
Sodium Acetate

Studies on Grafting Copolymerization of Lactic Acid onto Cornstarch Catalyzed with Sodium Hydroxide

2011 ◽  
Vol 233-235 ◽  
pp. 1906-1910
Author(s):  
Ying Mo Hu ◽  
Qing Ling Wang ◽  
Jian Hua Zhu ◽  
Yang Liu ◽  
Xue Yang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Lactic Acid ◽  
Sodium Hydroxide ◽  
Convenient Method ◽  
Graft Copolymerization ◽  
Good Adhesion ◽  
Acid Copolymer ◽  
Grafting Copolymerization ◽  
Grafting Degree

A convenient method to synthesize starch/lactic acid copolymer was studied in this work. Copolymer of starch graft with lactic acid (LA) was directly prepared by reaction of cornstarch with lactic acid in sodium hydroxide (NaOH) aqueous solution as a catalyst. The product was characterized by IR and WAXD, and the good adhesion between the two components has been observed by SEM. The results showed that the highest grafting degree could reach 33.60% when the graft copolymerization was carried in 0.40 mol·L-1 NaOH aqueous for 9 h at 90°C with the 1: 5~6 ratio of starch and lactic acid.

Behaviour of scleroglucan in aqueous solution containing sodium hydroxide

1987 ◽  
Vol 9 (3) ◽  
pp. 153-157 ◽  
Author(s):  
Shuquin Bo ◽  
Michel Milas ◽  
Marguerite Rinaudo
Keyword(s):  
Aqueous Solution ◽  
Sodium Hydroxide

Synthesis and bioactivity of novel C2-glycosyl triazole derivatives as acetylcholinesterase inhibitors

2017 ◽  
Vol 23 (3) ◽  
pp. 231-236 ◽  
Author(s):  
Long Yin ◽  
Lei Wang ◽  
Xiu-Jian Liu ◽  
Feng-Chang Cheng ◽  
Da-Hua Shi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sodium Hydroxide ◽  
Acetylcholinesterase Inhibitors ◽  
Acetylcholinesterase Inhibition ◽  
Inhibition Activity ◽  
Triazole Derivatives ◽  
Inhibitory Activities ◽  
Ellman’S Method

AbstractNew C2-glycosyl triazole derivatives 6a–l were synthesized by cyclization of glycosyl acylthiosemicarbazides 5 in refluxing 3 N sodium hydroxide aqueous solution. Substrates 5 were obtained by the reaction of glycosyl isothiocyanate 3 with various hydrazides. The acetylcholinesterase (AChE) inhibitory activities of compounds 6 were tested by Ellman’s method. Compounds that exhibited over 85% inhibition were subsequently evaluated for the IC50 values. Compound 6f possesses the best acetylcholinesterase-inhibition activity with IC50 of 1.46±0.25 μg/mL.

scholarly journals SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF 7-HYDROXY-3',4'-DIMETHOXYFLAVONE

2012 ◽  
Vol 12 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Elfi Susanti VH ◽  
Sabirin Matsjeh ◽  
Tutik Dwi Wahyuningsih ◽  
Mustofa Mustofa ◽  
Tri Redjeki
Keyword(s):  
Aqueous Solution ◽  
Antioxidant Activity ◽  
Sodium Hydroxide ◽  
Spectral Data ◽  
1H Nmr ◽  
13C Nmr ◽  
Room Temperature ◽  
Antioxidant Activities ◽  
Oxidative Cyclization ◽  
Dpph Method

Synthesis of flavones and their derivatives has attracted considerable attention due to their significant pharmaceutical effects. 7-hydroxy-3',4'-dimethoxyflavone has been synthesized and its antioxidant activity has been investigated. Flavone was synthesized by oxidative cyclization of chalcone. 2',4'-dihydroxy-3,4-dimethoxychalcone was prepared by Claisen-Schmidt condensation of 2,4-dihydroxyacetophenones with 3,4-dimethoxybenzaldehydes in the presence of aqueous solution of sodium hydroxide and ethanol at room temperature. Oxidative cyclization of 2',4'-dihydroxy-3,4-dimethoxychalcone was done by using I2 catalyst in DMSO to form 7-hydroxy-3',4'-dimethoxyflavone. The synthesized compounds were characterized by means of their UV-Vis, IR, 1H-NMR and 13C-NMR spectral data. The compound was tested for their antioxidant activities by DPPH method.

Colorimetric Determination of Oxyphenisatin and Oxyphenisatin Diacetate in Pharmaceutical Preparations

1964 ◽  
Vol 47 (4) ◽  
pp. 688-692
Author(s):  
Antoine Major
Keyword(s):  
Aqueous Solution ◽  
Organic Solvent ◽  
Silver Nitrate ◽  
Sodium Hydroxide ◽  
Column Chromatography ◽  
Sodium Hydroxide Solution ◽  
Pharmaceutical Preparations ◽  
Colorimetric Determination ◽  
Hydroxide Solution

Abstract A method is described which will quantitatively determine 0.1 mg oxyphenisatin or the diacetate in various pharmaceutical preparations. After removal of interferences by organic solvent extractions from aqueous solution and partition column chromatography, the reaction of oxyphenisatin (diacetate) with silver nitrate in alcoholic sodium hydroxide solution produces a violet solution, which follows Beer’s law (1—15 μg per ml). The method was satisfactorily applied to the assay of commercial tablets, liquids, and powders with recoveries, as per cent found of declared, in the range 95—101%.

Parameters Influences during Biodiesel Production

2010 ◽  
Vol 44-47 ◽  
pp. 4167-4175
Author(s):  
Anita Kovač Kralj ◽  
Davorin Kralj
Keyword(s):  
Aqueous Solution ◽  
Sodium Hydroxide ◽  
Diesel Engines ◽  
Renewable Resources ◽  
Batch Reactor ◽  
Methyl Esters ◽  
Alternative Fuel ◽  
Biodiesel Production ◽  
Compression Ignition ◽  
Diesel Production

Bio-diesel is a clean burning alternative fuel, produced from domestic, renewable resources. Bio-diesel can be blended at any level with petroleum diesel to create a bio-diesel blend. It can be used in compression-ignition (diesel) engines with little or no modification. Bio-diesel is simple to use, biodegradable, non-toxic, and essentially free of sulphur and aromatics. This paper presents the two following identifiable topic areas as key themes: 1. preparation of an aqueous solution of sodium hydroxide – as a catalyst, which can be activated by the most MeO- active groups, and can therefore be converted to methyl esters (biodiesel) from triglyceride. Methoxide (MeO-) was produced from sodium hydroxide (NaOH) and methanol (MeOH) in a batch reactor: NaOH + MeOH = H2O + Na+ + MeO-. During bio-diesel production, methoxide is incorrectly referred to as the product of mixing methanol and sodium hydroxide. An aqueous solution of sodium hydroxide – was prepared as a catalyst, by using different amounts of water at the same temperature. The reaction with lower water took place at the highest and quickest degrees of NaOH conversion and thus more MeO- active groups. The water was effective as an inhibitor.

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