نتایج جستجو برای: acidity and stability constants

تعداد نتایج: 16875693  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1389

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز - دانشکده کشاورزی 1389

abstract: since sugar consumption is directly related to diabetes and other illnesses such as obesity, the issue that will most heavily dominate the health food market is blood sugar management and low glycemic foods. using calcium chloride and gums such as sodium alginate and low ester pectin as thikener and a high-potency sweetener aspartame we were able to reduce sugar content of sour cherry...

Farrokh Gharib

The formation constants of the species formed in the systems fr + glycine + dioxovanadium(V) + and H+ + glycine have been determined in aqueous solutions of methanol at 25 °C and constant ionicstrength, using spectrophotometric and potentiometric techniques. It was shown thatdioxovanadium(V) forms two mononuclear 1 : land 1:2 complexes with glycine. The formationconstants in various media were ...

Journal: :Environmental science & technology 2004
Jianmin Wang Xinjun Teng Hao Wang Heng Ban

The surface physical-chemical characteristics of a class F coal fly ash were studied in an effort to establish a quantitative understanding of metal adsorption. The ash surface acidity (acid site density and acidity constant), surface electrical characteristics, and adsorption constants for selected heavy metal ions were determined using a batch titration method, an electrophoretic method, and ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1389

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

2014
Ali Yeganeh Faal Tavakol Heidary Shayeste Maryam Bordbar Bahare Jamalyan

Article history: Received March 28, 2013 Received in Revised form August 28, 2013 Accepted 27 November 2013 Available online 28 November 2013 In this work, acidity constants protonated form of 4.4'-bis astilbene-2,2'-disulfonic-disodium salts (TRIAZ) have been determined spectrophotometrically and spectrofluorimetrically at 25C and ionic strength of 0.1M KNO3. A program based on MCR-ALS applied...

Journal: :Organic & biomolecular chemistry 2006
Bernd Knobloch Helmut Sigel Andrzej Okruszek Roland K O Sigel

The dinucleotide d(pGpG) is an often employed DNA model to study various kinds of interactions between DNA and metal ions, but its acid-base properties were not yet described in detail. In this study the six deprotonation reactions of H4[d(pGpG)]+ are quantified. The acidity constants for the release of the first proton from the terminal P(O)(OH)2 group (pKa = 0.65) and for one of the (N7)H+ si...

2001
FREDERICK G. BORDWELL

The first acidity scale to be established in a pure solvent other than water was the result of the pioneering work of Conant, Wheland, and McEwen in ether or ben~ene .~ During the past 20 years an ion-pair acidity scale covering an "effective pKa rangefrom about 15 to 40 has been developed in cyclohexylamine (CHA),6 and similar studies in other low-dielectric-constant solvents including 1,2-dim...

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