Topic
Isopropyl alcohol
About: Isopropyl alcohol is a research topic. Over the lifetime, 3064 publications have been published within this topic receiving 27354 citations. The topic is also known as: Rubbing Alcohol & Propan-2-ol.
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TL;DR: Comparison of the activation parameters for the reactions in the two solvent systems as well as those in the i-PrOH/AN (1:1 v/v) reported earlier suggests that the AN medium promotes the reaction by activating the ground-state alcohol reactant through weak interactions with the electron pairs on alcohol O, while water and parent alcohol media facilitate the Reaction by H-bonding stabilization of the alcohol moiety of the TS.
Abstract: The rate constants of the hydride-transfer reactions from isopropyl alcohol (i-PrOH) to an NAD+ model, 9-phenylxanthylium ion (PhXn+), in acetonitrile (AN) and in water containing AN (80% H2O/20% AN) were determined over a temperature range from 36 to 67 °C. The reactions follow second-order rate laws. In the latter solution, formation of the water adduct of PhXn+ was observed as a side-equilibrium (K). The observed inverse solvent kinetic isotope effect (kH2Oobs/kD2Oobs = 0.54), the larger than unity equilibrium isotope effect (K(H2O)/K(D2O) = 2.69), and the results of acid effect on the observed rate constants of the reactions are consistent with the “side-equilibrium mechanism”. Kinetic isotope effects at all three H/D positions of i-PrOH for the net hydride-transfer process were determined in both solutions at 60 °C: KIEα-DH = 3.2(AN), 3.2(H2O); KIEβ-D6H = 1.05(AN), 1.16(H2O); KIEODH = 1.08(AN), 1.04(H2O). These KIE values are consistent with the presence of the positively charged alcohol moiety in th...
11 citations
Patent•
26 Oct 1993
TL;DR: In this article, a refined lactide having a high purity, readily polymerizing, and easily providing polylactic acid having an extremely high molecular weight was obtained by recrystallizing a lactide with a lower alcohol, then with benzene or an alkyl substituted group-containing benzene.
Abstract: PURPOSE: To obtain a refined lactide having a high purity, readily polymerizing, easily providing a polylactic acid having an extremely high molecular weight, by recrystallizing a lactide with a lower alcohol, then with benzene or an alkyl- substituted group-containing benzene CONSTITUTION: An unpurified lactide is added to a lower alcohol (eg isopropyl alcohol), heated to 70°C and completely dissolved When the solution is cooled to 30°C, a crystal is precipitated and filtered The prepared crystal is washed with water or isopropyl alcohol The prepared lactide is added to benzene or an alkyl-substituted benzene (eg toluene) and heated to 70°C to completely dissolve the lactide The solution is cooled to 30°C, a crystal is precipitated and filtered The prepared crystal is washed with a solvent and dried under reduced pressure to give the high-purity refined lactide providing a polylactic acid having an extremely high molecular weight COPYRIGHT: (C)1995,JPO
11 citations
TL;DR: In this article, the stability constants of the silver nitrate complex in solutions of various compositions have been evaluated by potentiometry using a silver electrode, and a method to produce constant ionic strength in orgnaic media of HNO3 + HClO4 was proposed.
11 citations
TL;DR: In this paper, the effects of PFAS characteristics, solvent type, water-to-organic solvent ratio, and temperature on the stability of 21 PFASs including 18 PFEAs were investigated.
Abstract: Per- and polyfluoroalkyl substances (PFASs) are widely used anthropogenic chemicals. For environmental and toxicological analysis, it is important to understand the stability of PFASs, including novel per- and polyfluoroalkyl ether acids (PFEAs), in commonly used solvents. In this study, we investigated the effects of PFAS characteristics, solvent type, water-to-organic solvent ratio, and temperature on the stability of 21 PFASs including 18 PFEAs. None of the studied PFASs showed measurable degradation in deionized water, methanol, or isopropyl alcohol over 30 days; however, nine PFEAs degraded in the polar aprotic solvents acetonitrile, acetone, and dimethyl sulfoxide (DMSO). PFEA degradation followed first-order kinetics, and first-order rate constants increased with increasing temperature and with decreasing water-to-organic solvent ratio. Monoethers with a carboxylic acid functional group adjacent to a tertiary carbon (>CF-COOH) degraded more rapidly than multiethers in which the carboxylic acid moiety was adjacent to repeating -CF2O- groups. In contrast, monoethers with a carboxylic acid moiety adjacent to a secondary carbon (-CF2-COOH) were stable in all tested solvents. Using high-resolution mass spectrometry, we determined that PFEAs with a >CF-COOH group were stoichiometrically decarboxylated in aprotic solvents and formed products with a >CFH group; e.g., hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX), HFPO-trimer acid, and HFPO-tetramer acid were stoichiometrically converted to Fluoroethers E-1, E-2, and E-3, respectively. PFEA degradation results highlight the importance of solvent choice when preparing dosing solutions and performing extractions for environmental and toxicological assessments of PFEAs.
11 citations
TL;DR: In this paper, the Gibbs free energies of transfer for [Co(CysOS)(en)2]- and S2O82− have been estimated for this ion in mixtures containing up to 40% acetone, t-butyl alcohol, isopropyl alcohol and acetonitrile.
Abstract: The kinetics of oxidation of cysteinatobis(ethylenediamine)cobalt(III) ion, [Co(CysOS)(en)2]+, by peroxodisulphate were investigated at different ionic strengths, adjusted with various electrolytes, and at different temperatures and concentrations of perchloric acid. Rate constants and activation parameters are also reported for this oxidation in mixtures containing up to 40% acetone, t-butyl alcohol, isopropyl alcohol, or acetonitrile. The solubilities of [Co(CysOS)(en)2]ClO4 and KClO4 have been determined in water and aqueous acetone and aqueous t-butyl alcohol at 298.2 K. From these values, Gibbs free energies of transfer for [Co(CysOS)(en)2]+ and S2O82– have been estimated. The solvent effects on the oxidation have been divided into their initial-state and transition-state components.
11 citations