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مرکز اطلاعات علمی SID1
مرکز اطلاعات علمی SID
اسکوپوس
مرکز اطلاعات علمی SID
ریسرچگیت
strs
نویسنده: 

RASTAGHI NAJMEH | ADIBMEHR ZAHRA

اطلاعات دوره: 
  • سال: 

    2016
  • دوره: 

    0
  • شماره: 

    22
تعامل: 
  • بازدید: 

    1050
  • دانلود: 

    0
چکیده: 

SULFONIC ACIDS ARE USED AS CATALYSTS. THE SIMPLEST EXAMPLES AREMETHANESULFONIC ACID, CH3SO2OH ANDP -TOLUENESULFONIC ACID, WHICH ARE REGULARLY USED IN ORGANIC CHEMISTRY AS ACIDS THAT ARE LIPOPHILIC (SOLUBLE IN ORGANIC SOLVENTS) [1]...

آمار یکساله:  

بازدید 1050

دانلود 0
نویسنده: 

BENVIDI ALI | JAHANBANI SHAHRIYAR

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    0
  • شماره: 

    18
تعامل: 
  • بازدید: 

    1785
  • دانلود: 

    0
چکیده: 

BACKGROUND: ORGANIC AZO DYES ARE APPLIED IN MANY INDUSTRIAL PROCESSES THEREFORE, THEY ARE FOUND IN INDUSTRIAL WASTEWATER, WHICH POSES A SERIOUS ENVIRONMENTAL PROBLEM [1]. THE acidity constants PLAY A KEY ROLE IN MANY ANALYTICAL PROCEDURES SUCH AS ACID-BASE TITRATION, SOLVENT EXTRACTION...

آمار یکساله:  

بازدید 1785

دانلود 0
نویسنده: 

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    0
  • شماره: 

    16
تعامل: 
  • بازدید: 

    1575
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

RANK ANNIHILATION FACTOR ANALYSIS (RAFA) IS AN EFFICIENT CHEMOMETRICS TECHNIQUE BASED ON RANK ANALYSIS FOR TWO-WAY SPECTRUM DATA AND CAN BE EMPLOYED TO QUANTITATIVELY ANALYZE THE GRAY SYSTEM WITH UNKNOWN BACKGROUND. IN THIS WORK, RANK ANNIHILATION FACTOR ANALYSIS METHOD WAS PROPOSED FOR DETERMINATION OF THE acidity constants OF DIPROTIC ACID OF 4- (2-THIAZOLYLAZO) -RESORCINOL (TAR). AFTER RECORDING THE ELECTRONIC ABSORBANCE SPECTRA OF THE ACIDS AT DIFFERENT PH, THE CONTRIBUTIONS OF BOTH H2A AND A2- WERE ANNIHILATED FROM THE ABSORBANCE DATA, WHICH MADE FEASIBLE THE DETERMINATION OF TWO SUCCESSIVE acidity constants. EXTRA TITRATION OF STANDARD AND AUGMENTATION WITH SAMPLE MATRIX AND ALSO THE MATRIX EFFECTS ARE AVOIDED IN THE PROPOSED METHOD. IN THIS ARTICLE, WE WILL SHOW THAT THE DETERMINATION OF THE SUCCESSIVE ACID DISSOCIATION constants OF DIPROTIC ACIDS CAN BE FEASIBLE BY RAFA IF THE CONTRIBUTIONS OF BOTH ACIDIC AND BASIC FORMS ARE ANNIHILATED FROM THE ORIGINAL DATA [1-4].

آمار یکساله:  

بازدید 1575

دانلود 0
گارگاه ها آموزشی
نویسنده: 

ASHRAF GANJOUEI T.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    0
  • شماره: 

    20
تعامل: 
  • بازدید: 

    2205
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

THE ACCURATE DETERMINATION OF acidity AND STABILITY constants VALUES ARE FUNDAMENTAL TO UNDERSTANDING THE BEHAVIOR OF LIGANDS AND THEIR INTERACTION WITH METAL IONS IN AQUEOUS SOLUTION. SUCH AN UNDERSTANDING IS IMPORTANT IN A WIDE VARIETY OF AREAS, SUCH AS METAL IONS IN BIOLOGY, IN BIOMEDICAL APPLICATIONS, METAL IONS IN THE ENVIRONMENT, EXTRACTION METALLURGY, FOOD CHEMISTRY AND METAL IONS IN MANY INDUSTRIAL PROCESSES. VARIOUS METHODS FOR THE DETERMINATION OF DISSOCIATION constants, SUCH AS POTENTIOMETRIC, SPECTROPHOTOMETRIC, CONDUCTOMETRIC, AND SPECTROSCOPIC METHODS, HAVE BEEN REPORTED.SPECTROPHOTOMETRIC METHOD IS APPLICABLE TO THE COMPOUNDS WHOSE CONCENTRATIONS OR EXTINCTION COEFFICIENTS ARE NOT DETERMINED. IT PROVIDES MORE EXACT DISSOCIATION constants THAN OTHER METHODS, EVEN FOR POLYPROTIC COMPOUNDS WITH ALMOST EQUAL PKA, VALUES AND COMPOUNDS WITH EXTREMELY ACIDIC OR EXTREMELY BASIC PROPERTIES. THE MOST WIDELY USED PROGRAMS AND ALGORITHMS FOR THE DETERMINATION OF acidity constants FROM SPECTROPHOTOMETRIC DATA ARE SQUAD, SPECFIT, DATAN AND KINFIT.IN THIS INVESTIGATION, SPECTROPHOTOMETRIC DATA WAS USED FOR THE DETERMINATION OF DISSOCIATION constants OF SOME DYES INCLUDING EOSIN Y, FAST GREEN FCF, 4- (2-PYRIDYLAZO) RESORCINOL (PAR) AND AMINO HYDROXY NAPHTHALENESULFINIC ACID IN AQUEOUS SOLUTION BY MEANS OF HYPSPEC PROGRAM AS A NEW VERSION OF PHAB PROGRAM. ALSO THE DISTRIBUTION DIAGRAMS WERE DEPICTED BY HYSS2009. THE OBTAINED RESULTS SHOW THE GOOD AGREEMENT WITH THOSE FROM LITERATURE.

آمار یکساله:  

بازدید 2205

دانلود 0
نویسندگان: 

BALUJA SH. | Ramavat p. | Nandha k.

اطلاعات دوره: 
  • سال: 

    2016
  • دوره: 

    27
  • شماره: 

    4
  • صفحات: 

    321-328
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    19846
  • دانلود: 

    8180
چکیده: 

The acidity constants of some synthesized protonated pyrazolo quinazoline compounds were determined potentiometrically at ionic strength of 0. 1 M in DMF: water (60: 40 v/v) system at different temperatures (298. 15 K to 318. 15 K). The pKa values have been found to increase with increasing electron-donating nature of substitutions. Some thermodynamics parameters such as enthalpy (Δ H° ), Gibb’ s free energy (Δ G° ) and entropy (Δ S° ) of reactions have also been evaluated at different temperatures for these systems. The thermodynamic parameters indicate that dissociation process is not spontaneous and exothermic.

آمار یکساله:  

بازدید 19846

دانلود 8180 استناد 0 مرجع 0
نویسنده: 

BENVIDI ALI | JAHANBANI SHAHRIYAR

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    0
  • شماره: 

    18
تعامل: 
  • بازدید: 

    945
  • دانلود: 

    0
چکیده: 

BACKGROUND: ORGANIC AZO DYES ARE APPLIED IN MANY INDUSTRIAL PROCESSES THEREFORE, THEY ARE FOUND IN INDUSTRIAL WASTEWATER, WHICH POSES A SERIOUS ENVIRONMENTAL PROBLEM [1]. THE acidity constants PLAY A KEY ROLE IN MANY ANALYTICAL PROCEDURES SUCH AS ACID-BASE TITRATION, SOLVENT EXTRACTION, COMPLEX FORMATION AND ION TRANSPORT.

آمار یکساله:  

بازدید 945

دانلود 0
strs
اطلاعات دوره: 
  • سال: 

    2018
  • دوره: 

    5
  • شماره: 

    1
  • صفحات: 

    67-79
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    17206
  • دانلود: 

    9222
چکیده: 

Recently, solution scanometry, as a new, simple, fast, portable, and economic method has been introduced for determination of acidity constants of indicators and dyes. In this study, a method was applied for the determination of the acidity constant of p-Rosolic acid (RA) and Bromoxylenol blue (BXB) indicators. The method is based on scanning of Plexiglas® sheet containing colored solutions with a flatbed scanner. The obtained images were analyzed to red, green, and blue (RGB) values using software written in visual basic 6. For comparison, the acidity constants of the indicators were determined by spectrophotometric method using the Hypspec program. The corresponding distribution diagrams were also drawn through the Hyss2009 program. The comparison between the presented and traditional UV-Vis spectrophotometric method was performed, and similar trends were observed in the results of both methods. The obtained values of pKa by solution scanometric and spectrophotometric methods showed a good agreement with the corresponding values reported in the literature.

آمار یکساله:  

بازدید 17206

دانلود 9222 استناد 0 مرجع 0
نویسنده: 

ZAREI T. | JAHANBANI S. | BENVIDI A.

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    0
  • شماره: 

    5
تعامل: 
  • بازدید: 

    1050
  • دانلود: 

    0
چکیده: 

IN THIS WORK, WE INTRODUCE A SIMPLE, SELECTIVE, SENSITIVE AND LOW COST PROCEDURE FOR DETERMINATION OF acidity constants OF CINNAMIC ACID AND CINNAMIC ACID DERIVATIES IN BINARY MIXTURES OF SOLVENT-WATER AT 25°C BY APPLYING RAFA AND TRAFA METHODS TO PH GRADUAL CHANGE-UV-VIS SPECTRAL DATA. ...

آمار یکساله:  

بازدید 1050

دانلود 0
نویسندگان: 

GOUDARZI MOHAMMAD | GOUDARZI T.

اطلاعات دوره: 
  • سال: 

    2008
  • دوره: 

    27
  • شماره: 

    4
  • صفحات: 

    15-20
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    17785
  • دانلود: 

    11711
چکیده: 

In this work the acidity constants of Thiamine in water and water-Triton X-100 micelle media solutions, at 25oC, have been determined spectrophotometrically. To evaluate the pH- absorbance data, a resolution based on the combination of soft-and hard-modeling is applied. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program was applied for determination of acidity constants. Results showed that the pKa values of Thiamine were influenced as the percentages of a nonionic surfactant, such as triton X-100, added to the solution of this reagent increased. Effect of surfactant on acidity constants and pure spectrum of each component are also discussed.

آمار یکساله:  

بازدید 17785

دانلود 11711 استناد 0 مرجع 0
نویسنده: 

MAHDAVI A. | MALEKSHAHIAN M.

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    0
  • شماره: 

    5
تعامل: 
  • بازدید: 

    1680
  • دانلود: 

    0
چکیده: 

A COMPARATIVE STUDY ABOUT ADVANTAGES AND LIMITATIONS OF NET ANALYTE SIGNAL (NAS) AND DATA ANALYSIS (DATAN) PROGRAM IN CONSTANT ACID ANALYSIS HAS BEEN PERFORMED. ...

آمار یکساله:  

بازدید 1680

دانلود 0
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