scholarly journals PREPARATION OF CHITOSAN-GOLD NANOPARTICLES: PART 2. THE ROLE OF CHITOSAN

2010 ◽  
Vol 8 (3) ◽  
pp. 320-326 ◽  
Author(s):  
Adlim Adlim ◽  
Mohamad Abu Bakar
Keyword(s):  
Gold Nanoparticles ◽  
Acetic Acid ◽  
Colloidal Particles ◽  
Acetic Acid Solution ◽  
Molar Ratio ◽  
Plasmon Band ◽  
Gold Particles ◽  
Chitosan Matrix ◽  
Metal Colloid

Colloidal gold nanoparticles prepared by employing chitosan as the stabilizer in solvent of methanol-acetic acid solution were stable for months without precipitation. The mole ratio of chitosan-gold ions of 5:1 - 30:1 gave dispersed and fine gold particles in range of 9.4-10.4 nm. Gold reduction in chitosan matrix was faster at higher chitosan concentration, and molar ratio of chi : Au, from 5:1 to 40:1. Higher acidity of acetic acid (pH 2-6) led to faster reduction of gold ions. The intensity of gold metal colloid plasmon band increased at higher concentration of acetic acid. Chitosan functioned both as a stabilizer and a reducing agent for gold ions. Gold colloidal particles immobilized on chitosan coated TiO2 as the solid support gave more dispersed and smaller particles (4.6 nm) compared with gold particles supported on TiO2 without chitosan coating.   Keywords: gold nanoparticles, chitosan, chitosan coated TiO2

scholarly journals Role of the environment in the stability of anisotropic gold particles

2015 ◽  
Vol 17 (9) ◽  
pp. 6305-6313 ◽  
Author(s):  
Robinson Cortes-Huerto ◽  
Jacek Goniakowski ◽  
Claudine Noguera
Keyword(s):  
Gold Nanoparticles ◽  
Gold Particles ◽  
The Stability

We highlight the conditions under which energy differences between isotropic and elongated gold nanoparticles are reduced, thus prompting their thermodynamic coexistence.

CsPr2(CH3COO)7, ein caesiumarmes wasserfreies ternäres Caesium-Praseodym-Acetat / CsPr2(CH3COO)7, a Cesium Poor Anhydrous Ternary Cesium Praseodymium(III) Acetate

1993 ◽  
Vol 48 (7) ◽  
pp. 886-892 ◽  
Author(s):  
Adalbert Lossin ◽  
Gerd Meyer
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Acid Solution ◽  
Single Crystals ◽  
Acetic Acid Solution ◽  
Three Dimensional ◽  
Molar Ratio ◽  
Triclinic System ◽  
Dimensional Network ◽  
Oxygen Atoms

Single crystals of CsPr2(CH3COO)7 were obtained from an acetic acid solution of Pr(CH3COO)3 • H2O and Cs2CO3 in a molar ratio of 4:1 at 120°C. It crystallizes in the triclinic system, PĪ (no. 2), Z = 2, a = 1028.1(5), b = 1034.6(5), c = 1199.4(6) pm, α = 84.82(2), β = 67.07(3), γ = 76.01(2)°, Vm = 343.3(3) cm3/mol, R = 0.031, Rw = 0.027. The crystal structure contains infinite chains, 1∞[Pr2(CH3COO)6], running along the [110] direction. The chains are built up by bridging acetate ions coordinated to two crystallographically different Pr3+ ions which are both surrounded by 9 oxygen ligands. These chains are linked by “intercalated” Cs(CH3COO) to layers parallel (100). Cs+ has contacts to oxygen atoms of neighbouring layers, such that a three-dimensional network is formed.

HYDROGEN EXCHANGE REACTIONS OF PHENOL ETHERS IN ACETIC ACID SOLUTION. PROMOTIVE AND INHIBITORY EFFECTS OF STERIC ORIGIN

1949 ◽  
Vol 27b (4) ◽  
pp. 398-407 ◽  
Author(s):  
Weldon G. Brown ◽  
Kenneth E. Wilzbach ◽  
Wilbert H. Urry
Keyword(s):  
Acetic Acid ◽  
Sulphuric Acid ◽  
Hydrogen Exchange ◽  
Acetic Acid Solution ◽  
Side Reactions ◽  
Exchange Reactions ◽  
Inhibitory Effects ◽  
Hydrogen Deuterium ◽  
Iodide Solution

As a means of avoiding side reactions which were encountered in earlier studies of hydrogen-deuterium exchange of phenol ethers with ethanol-sulphuric acid mixtures, a new procedure has been devised for the study of exchange reactions in acetic acid. The analysis for deuterium in the carboxyl group of acetic acid is performed by adding methyl magnesium iodide solution to the solution of phenol ether in acetic acid, combustion of the methane so produced, and finally, by determining the density of the water formed in the combustion. As compared with the former procedure, which required fractionation of the reaction mixture to recover the pure constituents, advantages in convenience and accuracy are claimed. Results are reported for the following ethers, reacting at 90 °C. in the presence of trace quantities of sulphuric acid: anisole, o-methylanisole, m-methylanisole, 3,5-dimethylanisole, 2-methylcoumarane, veratrole, di-isobutyl catechol ether, and the cyclic mono- (di-, tri-, and tetra) methylene ethers of catechol. The observed variations in rates are interpreted in part according to whether the conditions imposed by structural alterations favor or constrain the formation of an intermediate cation for which a quinoidal configuration of bonds is required. The role of steric factors is most strikingly demonstrated in the series of cyclic ethers of catechol, constraint being evident at a critical ring size (7-membered ring) and largely absent for either smaller or larger rings.

Role of SOD in the protection of Rhizophora mangle on gastric injury induced by ethanol, ischaemia-reperfusion and acetic acid in rats

Planta Medica ◽  
2009 ◽  
Vol 75 (09) ◽  
Author(s):  
FM de-Faria ◽  
A Luiz-Ferreira ◽  
ACA Almeida ◽  
V Barbastefano ◽  
MA Silva ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Rhizophora Mangle ◽  
Gastric Injury ◽  
Ischaemia Reperfusion

Some Approaches to Viscometric Study of Chitosan in Acetic Acid Solution

2016 ◽  
Vol 10 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Valentina Chernova ◽  
◽  
Angela Shurshina ◽  
Elena Kulish ◽  
Gennady Zaikov ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Intrinsic Viscosity ◽  
Acetic Acid Solution ◽  
Conformational State ◽  
Macromolecular Coil ◽  
Degree Of Swelling ◽  
Current Value ◽  
Viscometric Study

Some ways of estimating the values of the intrinsic viscosity of chitosan were analyzed. It was shown that the method of Irzhak and Baranov for estimating the current value of the intrinsic viscosity allows to adequately estimates the conformational state of the macromolecular coil and its degree of swelling.

HPLC-UV Method for Determination of Famotidine from Pharmaceutical Products

2018 ◽  
Vol 69 (2) ◽  
pp. 297-299
Author(s):  
Adriana Nita ◽  
Delia Mirela Tit ◽  
Lucian Copolovici ◽  
Carmen Elena Melinte (Frunzulica) ◽  
Dana Maria Copolovici ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Quantitative Analysis ◽  
Linear Response ◽  
Mobile Phase ◽  
Acetic Acid Solution ◽  
Pharmaceutical Products ◽  
Quantification Limit ◽  
Validation Parameters ◽  
Hplc Analyses

The aim of this study was to develop and validate a rapid, accurate, and exact method for the quantitative determination of famotidine in pharmaceutical products. The HPLC analyses were performed by using a mobile phase containing methanol:1% acetic acid solution=30:7 (v/v), at a flow rate of 0.4 mL/min.The total time of the method was 10 min, and the retention time of famotidine was 4.16 min. The detection was evaluated at l=267 nm. The method has been validated by using different validation parameters. The linear response of the detector for famotidine peak area was observed at concentrations ranging from 0.1 to 0.0001 mg mL-1 , resulting in a correlation coefficient of 0.99998. The values of the detection limit and of the quantification limit are 0.00048 mg mL-1 and 0.00148 mg mL-1, respectively. The method proposed allowed accurate (with a relative error of less than 2%) and precise (RSD values less than 2.0%) determination of famotidine content in pharmaceutical products and can be used for its rapid quantitative analysis.

The role of acetic acid in FeCO3 scale deposition on CO2 corrosion of API X65 carbon steel under high temperatures

2021 ◽  
pp. 1-12
Author(s):  
Bernardo Augusto Farah Santos ◽  
Rhuan Costa Souza ◽  
Maria Eduarda Dias Serenario ◽  
Eugenio Pena Mendes Junior ◽  
Thiago Araujo Simões ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Carbon Steel ◽  
High Temperatures ◽  
Co2 Corrosion ◽  
Scale Deposition

Role of Indole-3-Acetic Acid in NAFLD Amelioration After Sleeve Gastrectomy

2021 ◽  
Author(s):  
Yu Wang ◽  
Geng Wang ◽  
Jie Bai ◽  
Ning Zhao ◽  
Qingbo Wang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sleeve Gastrectomy ◽  
Indole 3 Acetic Acid

scholarly journals THE RÔLE OF ACETIC ACID IN THE BIOSYNTHESIS OF HEME

1950 ◽  
Vol 184 (2) ◽  
pp. 755-767 ◽  
Author(s):  
Norman S. Radin ◽  
D. Rittenberg ◽  
David Shemin
Keyword(s):  
Acetic Acid
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