Determination of Isopropyl Alcohol in Presence of Acetone, and of Methylethylketone in Presence of Secondary Butyl Alcohol

1927 ◽  
Vol 19 (9) ◽  
pp. 1061-1062 ◽  
Author(s):  
H. A. Cassar
Keyword(s):  
Isopropyl Alcohol ◽  
Butyl Alcohol

A new method for the determination of the relative acidities of alcohols in alcoholic solutions. The nucleophilicities and competitive reactivities of alkoxides and phenoxides

1979 ◽  
Vol 57 (20) ◽  
pp. 2747-2754 ◽  
Author(s):  
Wilkins Reeve ◽  
Charles M. Erikson ◽  
Patrick F. Aluotto
Keyword(s):  
Isopropyl Alcohol ◽  
Butyl Alcohol ◽  
New Method ◽  
Butyl Bromide ◽  
Tert Butyl ◽  
Ether Mixture ◽  
Tert Butyl Alcohol ◽  
Relative Nucleophilicity ◽  
Semiquantitative Method

A new semiquantitative method has been developed for measuring the relative acidities of methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol in mixed hydroxylic solvents. A solution of the alkoxides of two alcohols in an excess of the two alcohols is allowed to react with n-butyl bromide to form a mixture of two ethers. The composition of the ether mixture is a measure of the "competitive reactivity" of thetwo alkoxides. This can be measured directly, and in theory can be factored into two components: the relative nucleophilicity and the relative basicity of the two alkoxides. Relative nucleophilicities are determined by using solutions in which phenol is one component. Knowing the competitive reactivities and nucleophilicities, the relative acidities of methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol in alcoholic media are shown to be 4.4, 1.0, 0.24, and 0.21, respectively. The relative nucleophilicities of hydroxide, methoxide, ethoxide, isopropoxide, tert-butoxide, phenoxide, and m-cresoxide are 0.08, 0.82, 1.0, 0.4, 0.04, 0.46, and 0.57 respectively.

Solubility and Thermodynamic Transfer Functions of Cesium Dianilinetetraisothiocyanatochromate(III)

1998 ◽  
Vol 63 (3) ◽  
pp. 293-298
Author(s):  
Vladislav Holba
Keyword(s):  
Experimental Data ◽  
Isopropyl Alcohol ◽  
Transfer Functions ◽  
Butyl Alcohol ◽  
Aqueous Methanol ◽  
Gibbs Energies ◽  
Gibbs Energy Of Transfer ◽  
Energy Of Transfer ◽  
The Given ◽  
Reference Electrolyte

The solubilities of cesium dianilinetetraisothiocyanatochromate(III) in water as well as in aqueous methanol, isopropyl alcohol, tert-butyl alcohol and acetonitrile were measured as a function of temperature and solvent composition. The Gibbs energies, enthalpies and entropies of transfer of the salt from water to the given solvents have been evaluated from experimental data. The contribution of [Cr(C6H5NH2)2(NCS)4]- ion to the Gibbs energy of transfer of the investigated salt has been calculated using the tetraphenylarsonium tetraphenylborate (TATB) reference electrolyte assumption.

A Headspace Gas Chromatographic Method for Determination of Formic acid Content in Isosulfan Blue and in Various Drugs

2021 ◽  
Vol 37 (2) ◽  
pp. 321-329
Author(s):  
Nilesh Takale ◽  
Neelakandan Kaliyaperumal ◽  
Gopalakrishnan Mannathusamy ◽  
Rajarajan Govindasamy
Keyword(s):  
Sulfuric Acid ◽  
Formic Acid ◽  
Chromatographic Method ◽  
Isopropyl Alcohol ◽  
Class Iii ◽  
Drug Substances ◽  
Headspace Gas ◽  
Concentrated Sulfuric Acid ◽  
Gas Chromatographic Method

The Pharmaceutical industry uses formic acid in the manufacturing of various drug substances or API. At the time of manufacturing of API formic acid is use as an oxidizing agent. Formic acid is the simplest carboxylic acid. It also called methanoic acid.Formic acid present in API at high concentrations is very hazardous but in low concentrations is very beneficial. The developed and validated method was short, precise, cost effective and reproducible with FID detector and easy to use. The method is a selective and superficial analytical method for determination of formic acid in different drug substances. We report here the development and validation study of headspace gas chromatographic method to determine formic acid in different drug substances we are reported here. As per this method, the drug sample was dissolved in 0.1% (v/v) of concentrated sulfuric acid in isopropyl alcohol (IPA) in a GC headspace vial and 0.1% (v/v) of concentrated sulfuric acid in isopropyl alcohol used as a diluent. A AB-Inowax capillary column (30 m x 0.32 mm I.D. and 0.5 µm film thickness) was used under gradient conditions with FID. The formic acid peak was well separated from all other solvents that are used in synthesis of particular drug substance. The LOD and LOQof the method for formic acid are 82 ppm and 249 ppm respectively. Formic acid are low toxic class-III solvent as per ICH guideline.

scholarly journals The multivariate calculation of material balances of flowsheets for separating ternary mixtures of different physical-chemical nature

2016 ◽  
Vol 11 (3) ◽  
pp. 47-57 ◽  
Author(s):  
A. V. Frolkova ◽  
M. A. Ablizin ◽  
M. A. Mayevskiy ◽  
A. K. Frolkova
Keyword(s):  
Phase Diagrams ◽  
Chemical Nature ◽  
Material Balance ◽  
Ternary Systems ◽  
Butyl Alcohol ◽  
Ternary Mixtures ◽  
Two Phase ◽  
Physical Chemical ◽  
Alcohol Water

An approach to the determination of free variables required for calculating the material balance of the flowsheet of ternary mixtures separation is presented. Phase diagrams of the considered ternary systems are characterized by the presence of a two-phase splitting area and by the presence of different amounts of azeotropes (classes 3.1.0, 3.1.1, 3.2.1 and 3.3.1). For all the systems flowsheets containing three rectification columns and a florentine vessel for separation were suggested. The multivariance of the solution of the balance problem was shown. The approach was illustrated by the example of real ternary systems characterized by different phase diagrams (methanol - chloroform - water, butyl alcohol - water - toluene, nitromethane - hexane - water). The parameters of the rectification columns were presented.

scholarly journals Determination of the dipole moments of some polar liquids dissolved in polar solvents

1969 ◽  
Vol 47 (20) ◽  
pp. 3767-3771 ◽  
Author(s):  
H. A. Rizk ◽  
N. Youssef ◽  
H. Grace
Keyword(s):  
Dipole Moments ◽  
Butyl Alcohol ◽  
Polar Solvents ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Initial Decrease ◽  
Interacting Systems ◽  
Solvent Molecules ◽  
Onsager Equation

The application of a modified form of the Onsager equation at the condition of infinite dilution of a polar solute in a polar solvent leads to reasonable dipole moments for water, pyridine, acetone, tert-butyl alcohol, n-butyl alcohol, and β-octyl alcohol, except in the case of water in tert-butyl alcohol at 30 and 40 °C and the case of acetone in n-butyl alcohol at 30 to 50 °C. The initial decrease of the dielectric constant of solvent by addition of solute in each of these two cases is associated with a reduction in the Kirkwood g-factor of solute. In all 12 systems investigated, strong hydrogen bonding occurs between solute and solvent molecules and often between solvent molecules themselves. It is thought that this equation must fail when short-range interactions assume predominant importance, but why it works so well for those cases which are also strongly interacting systems is not clear.

Determination of Cholesterol by p-Nitrobenzoate Derivatization and Liquid Chromatography

1994 ◽  
Vol 77 (5) ◽  
pp. 1190-1196 ◽  
Author(s):  
Thomas W Hamill ◽  
Abdel M Soliman
Keyword(s):  
Dairy Products ◽  
Isopropyl Alcohol ◽  
Methylene Chloride ◽  
Limit Of Detection ◽  
Lipid Extraction ◽  
Diode Array ◽  
Gas Chromatographic Method ◽  
Certified Values ◽  
Peak Purity

Abstract The method involves direct saponification and formation of the sterol p-nitrobenzoate (PNB) derivatives or lipid extraction with methylene chloride and isopropyl alcohol, saponification, fatty acid methylation, and formation of the sterol PNB derivatives. The sterol PNB derivatives are separated on a C8 column with a mobile phase of acetonitrile-hexane-water (250 + 30 + 3) and quantitated by UV detection at 280 nm. The limit of detection for cholesterol is 2 ng. The response was linear over a range of 4 to 250 ng (r = 0.999). Assays of NIST SRM 1845 and 1563 by this method gave results that were closer to the certified values than were results obtained by the AOAC gas chromatographic method. Reproducibility was evaluated by using foods containing low, medium, and high levels of cholesterol. The % coefficient of variation ranged from 1.8 to 6.7. Studies on a wide variety of food products (using lipid extraction and saponification-methylation) gave a mean recovery of 87.5 ± 10.1%. Direct saponification of poultry and dairy products gave a mean recovery of 101.3 ± 15.8%. Peak purity was determined by diode array spectrophotometry.

Analysis of Sodium Diphenylhydantoin and Phenobarbital Combinations by Nonaqueous Titration

1968 ◽  
Vol 51 (5) ◽  
pp. 1013-1016
Author(s):  
Sura J P Agarwal ◽  
Martin I Blake
Keyword(s):  
Exchange Resin ◽  
Cation Exchange Resin ◽  
Ammonium Hydroxide ◽  
Butyl Alcohol ◽  
Dosage Forms ◽  
Direct Titration ◽  
Titration Procedure ◽  
Tert Butyl Alcohol ◽  
Preliminary Separation

Abstract A simple, nonaqueous titration procedure is described for the determination of sodium diphenylhydantoin and phenobarbital combinations. Preliminary separation of the components is unnecessary. The phenobarbital content is determined by direct titration in tert.-butyl alcohol, using sodium methoxide or triethyl n-butyl ammonium hydroxide as the titrant. The total acidity is determined by titration of the sample after passage through a cation exchange resin (Amberlite IRC-50). The sodium diphenylhydantoin content is obtained by difference. Quantitative recoveries were obtained for synthetic mixtures and commercially available dosage forms

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