Solubility of benzilic acid in select organic solvents at 298.15 K

Experimental solubilities are reported for benzilic acid dissolved in ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 2-propanol, 2-butanol, 2-methyl-1-propanol, diethyl ether and methyl tert-butyl ether at 298.15?K. Results of these measurements reveal that the observed solubilities in the nine alcohol solvents fall within a fairly narrow mole fraction range of each other. Benzilic acid is also very soluble in the two ether solvents studied.     

Phase equilibria in the binary mixtures formed by ethylbenzene with some aliphatic alcohols at 95.8 kPa

Phase equilibria are determined over the entire composition range, through measurements on the bubble points of the binary mixtures of ethylbenzene with methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol and tert-butanol. A Swietoslawski-type ebulliometer is used for the measurements. The liquid phase composition versus temperature measurements, found to be well represented by the Wilson model, are used to establish the phase equilibria.     

Determination of Oxygenates in Gasoline by GC×GC

Comprehensive two‐dimensional gas chromatography (GC×GC) has been applied to the quantitation of oxygenates in reformulated gasoline. Target oxygenates were C₁–C₄ alcohols, tert‐pentanol, methyl tert‐butyl ether (MTBE), diisopropyl ether (DIPE), ethyl tert‐butyl ether (ETBE), and tert‐amyl methyl ether (TAME). These were separated from the gasoline matrix using a volatility‐based selectivity in the first chromatographic dimension, followed by a mixed‐phase polarity/shape selectivity in the second dimension. The high resolving power of this stationary phase combination completely separated all oxygenates except DIPE, ETBE, and TAME, which exhibited coelution with other nonpolar gasoline components. Oxygenates quantitation was achieved with the use of an internal standard, an FID detector, and calibration curves. Quantitation results are in good agreement with ASTM and EPA standard methods. When coupled with our previous method for BTEX and aromatics, a single GC×GC method can now quantitate MTBE, alcohols, BTEX, and aromatics in a one‐hour analysis.     

Excess molar enthalpies at 298.15 k of the binary mixtures

We have determined the excess molar enthalpies H _m ^E at 298.15 K and normal atmospheric pressure for the binary mixtures containing tert-butyl methyl ether (MTBE)+(methanol, ethanol, 1-propanol, 1-pentanol) using a Calvet microcalorimeter. This revised version was published online in July 2006 with corrections to the Cover Date.     

Activity coefficients of the binary mixtures of n-decane with some aliphatic alcohols at 95.8 kPa

Activity coefficients at 95.8?kPa (over the whole composition range) are evaluated from the measurements on the bubble point temperatures of the binary mixtures of n-decane with: iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol and active amylalcohol. A Swietoslawski-type ebulliometer is used for the measurements. The Wilson model, found to represent the liquid phase composition versus temperature data well, is used for the calculations.     

Grafting onto polypropylene II. Solvent effect on graft copolymerization of acrylonitrile by preirradiation method

Acrylonitrile (AN) has been graft copolymerized onto isotactic polypropylene (IPP) by the preirradiation method using Co⁶⁰ as the source of gamma rays in the presence of ethanol, n-propanol, isopropanol, n-butanol, tert. butyl alcohol, and n-pentanol. Alcohols vary in their ability to influence grafting of AN onto IPP and the following reactivity order was found: n-pentanol > n-butanol > tert.-butanol > n-propanol > ethanol > isopropanol. An attempt has been made to explain the observed reactivity pattern shown by different alcohols. Thermal behavior of the graft copolymer has been compared with that of IPP and irradiated IPP and it was observed that grafted IPP is thermally more stable than IPP and irradiated IPP.     

Use of the sulfide minerals pyrite and chalcopyrite as electrochemical sensors in non-aqueous solutions. The potentiometric titration of weak acids in alcohols

Natural monocrystalline pyrite and chalcopyrite were examined as new indicator electrodes for the potentiometric titration of weak acids in tert-butanol and iso-propanol. The electrodes investigated demonstrated a linear dynamic response for p-toluenesulfonic acid concentrations in the range from 0.1 to 0.001 M, with a Nernstian slope of 48 mV per decade for pyrite in tert-butanol. Sodium methylate, potassium hydroxide and tetrabutylammonium hydroxide (TBAH) proved to be suitable titrating agents. The response time was less than 12 s and the lifetime of the electrodes was higher than 1 year. The advantages of the electrodes are long-term stability, rapid response, reproducibility, easy preparation and low cost.      

Simultaneous measurement of methyl tert‐butyl ether and tert‐butyl alcohol in human serum by headspace solid‐phase microextraction gas chromatography–mass spectrometry

The abundant production of methyl tert‐butyl ether (MTBE) and its widespread use have led to an increase in the potential for human exposure. This work described a simple, fast, sensitive, reliable and low‐cost method for the simultaneous measurement of MTBE and its metabolite, tert‐butyl alcohol (TBA) in human serum by headspace solid‐phase microextraction gas chromatography–mass spectrometry. Extraction conditions were optimized and 40 °C, 10 min, 250 rpm and 0.3 g NaCl for a 1 mL sample were the optimal conditions. This method showed good analytical performance in terms of sensitivity with limits of detection in serum (1 mL) of 0.03 µg/L for MTBE and 0.05 µg/L for TBA, accuracy (mean recovery values) from 75.8% to 85.8%, precision (relative standard deviations) <10% and sample stability (biodegradation) <10% after 28 days. A verification experiment proved the reproducibility and stability of this method as well. Finally the method was used to detect 212 specimens, and the internal dose levels for MTBE in human serum were presented in China. Copyright © 2015 John Wiley & Sons, Ltd.     

Henry’s law constants and infinite dilution activity coefficients of cis-2-butene,dimethylether, chloroethane,and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol,isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol,and 2-methyl-2-butanol

Henry’s law constants and infinite dilution activity coefficients of cis-2-butene, dimethylether, chloroethane, and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol in the temperature range of 250 K to 330 K were measured by a gas stripping method and partial molar excess enthalpies were calculated from the activity coefficients. A rigorous formula for evaluating the Henry’s law constants from the gas stripping measurements was used for the data reduction of these highly volatile mixtures. The uncertainty is about 2% for the Henry’s law constants and 3% for the estimated infinite dilution activity coefficients. In the evaluation of the infinite dilution activity coefficients, the nonideality of the solute such as the fugacity coefficient and Poynting correction factor cannot be neglected, especially at higher temperatures. The estimated uncertainty of the infinite dilution activity coefficients includes 1% for nonideality.     

Catalytic activity of carbon nanotubes in the conversion of aliphatic alcohols

Carbon nanotubes (CNTs) obtained via the catalytic pyrolysis of hexane at 750°C were studied as the catalysts in conversion of C₂–C₄ alcohols. The efficiency of CNTs as catalysts in dehydration and dehydrogenation of ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and tert-butanol was studied by means of pulse microcatalysis. The surface and structural characteristics of CNTs are investigated via SEM, TEM, DTA, BET, and XPS. CNTs are shown to be effective catalysts in the conversion of alcohols and do not require additional oxidative treatment. The regularities of the conversion of aliphatic alcohols, related to the properties of the CNTs surface and the structure of the alcohols are identified.     

Abraham model correlations for describing the solubilising character of 3-Methoxy-1-butanol and 1-tert-Butoxy-2-propanol solvents

Experimental solubilities are measured for 18 crystalline organic nonelectrolyte solutes dissolved in 3-methoxy-1-butanol and for 23 crystalline organic nonelectrolyte solutes dissolved in 1-tert-butoxy-2-propanol. The measured experimental data, combined with published literature data, are used to determine Abraham model correlations for the two alkoxyalcohol solvents. The derived Abraham model correlations back-calculated the observed solubilities to within 0.12 log units.     

XAD-2 HPTLC Method of Identification and Determination of Some Synthetic Food Colourings

Abstract

An HPTLC method for identification and determination of 12 synthetic dyes (Amaranth, Allura red, Brilliant black BN, Brilliant blue E, Carmoisine, Erythrosine, Indigotine, Patent blue V, Ponceau 4R, Quinoline yellow, Sunset yellow, Tartazine) has been developed. Amberlite XAD-2 was used as a stationary phase for column chromatography. Elution was performed with various acidified alcohols (i-propanol, n-propanol, n-butanol) and recoveries between 81.5 - 100.2% were obtained. The low limit of detection is in the range of 4 – 10 ng. The method was tested on commercial products as: carbonated soda, candies, chewing gum, identical natural flavours, etc.     

H4SiW12O40 as the catalyst for the hydration and alcohol addition to 2-methylpropene

Catalytic hydration of 2-methyl-2-propene to tert-butanol (TBA) and alkylation with methanol to methyl-tert-butyl ether (MTBE) with dodecatungstosilicic acid H₄SiW₁₂O₄₀ as catalyst were investigated in a constant flow reactor at 40–80 °C. The catalyst is active in both reactions and exhibits high selectivities. The mechanisms of both reactions involving protonated intermediates were proposed.     

Experimental excess molar volumes of the ternary mixture and comparisonwith several empirical methods

Experimental excess molar volumes for the ternary system {x₁MTBE+x₂1-propanol+(1–x₁–x₂)nonane} and the three involved binary mixtures have been determined at 298.15 K and atmospheric pressure. Excess molar volumes were determined from the densities of the pure liquids and mixtures, using a DMA 4500 Anton Paar densimeter. The ternary mixture shows maximum values around the binary mixture MTBE+nonane and minimum values for the mixture MTBE+propanol. The ternary contribution to the excess molar volume is negative, with the exception of a range located around the rich compositions of 1-propanol. Several empirical equations predicting ternary mixture properties from experimental binary mixtures have been applied.     

Monomeric tert-Butanol in Benzene and Cyclohexane Solutions: A Fourier-Transform Infrared Spectroscopy Study

The dependence of the hydroxyl stretching frequency of monomeric tert-butanol in cyclohexane and benzene solutions on concentration was studied at different temperatures. The –OH group in the monomeric form of the alcohol appears to experience very small or negligible alcohol concentration effects. This is attributed to the ability of tert-butanol to form dimers by hydrogen bonding, which in turn shield their polar groups from monomeric tert-butanol. As a result, the environment that the latter interacts with consists of weakly polar or nonpolar species (cyclohexane or benzene), and the nonpolar (methyl) groups of dimeric tert-butanol.     

Study on volumetric measurement and correlations for MTBE+1-propanol+decane at 298.15 K and atmospheric pressure

Summary Experimental densities for the ternary mixture x₁MTBE+x₂1-propanol+(1-x₁-x₂)decane and the binary mixtures xMTBE +(1-x)1-propanol and x1-propanol+(1-x)decane have been measured at 298.15 K and atmospheric pressure, using a DMA 4500 Anton Paar densimeter. Excess molar volumes were determined from the densities of the pure liquids and mixtures. Attending to the symmetry of the studied mixtures, suitable fitting equations have been used in order to correlate adequately the experimental data. For the ternary mixture, experimental data were also used to test several empirical expressions for estimating ternary properties from experimental binary results.     

Synthesis and Structure of 1-tert-Butyl-3-R-tetrazolium Salts

An effective method was developed for the synthesis of 1,3-disubstituted tetrazolium salts by the quaternization of 2-monosubstituted tetrazoles, including functionally substituted compounds, with tert-butanol in 72% perchloric acid. An X-ray diffraction investigation of examples of this series of salts - 1-tert-butyl-3-(1-methylvinyl)- and 1,3-di-tert-butyltetrazolium perchlorates - was carried out.