The reaction of the OH radicals with 4-hydroxy-2-butanone was investigated in the gas phase using an absolute rate method at room temperature and over the pressure range 10-330 Torr in He and air as diluent gases. The rate coefficients were measured using pulsed laser photolysis (PLP) of H(2)O(2) to produce OH and laser induced fluorescence (LIF) to measure the OH temporal profile. An average value of (4.8 ± 1.2) × 10(-12) cm(3) molecule(-1) s(-1) was obtained. The OH quantum yield following the 266 nm pulsed laser photolysis of 4-hydroxy-2-butanone was measured for the first time and found to be about 0.3%. The investigated kinetic study required accurate measurements of the vapor pressure of 4-hydroxy-2-butanone, which was measured using a static apparatus. The vapor pressure was found to range from 0.056 to 7.11 Torr between 254 and 323 K. This work provides the first absolute rate coefficients for the reaction of 4-hydroxy-2-butanone with OH and the first experimental saturated vapor pressures of the studied compound below 311 K. The obtained results are compared to those of the literature and the effects of the experimental conditions on the reactivity are examined. The calculated tropospheric lifetime obtained in this work suggests that once emitted into the atmosphere, 4H2B may contribute to the photochemical pollution in a local or regional scale.

No abstract

Vapor pressures of five saturated fatty acid ethyl esters (FAEEs), ethyl hexanoate (or ethyl caproate), ethyl octanoate (or ethyl caprylate), ethyl decanoate (or ethyl caprate), ethyl dodecanoate (or ethyl laurate), and ethyl tetradecanoate (or ethyl myristate), were measured at pressures from 1 Pa to 180 kPa and temperatures from (253.15 to 463.15) K using a static apparatus. These esters are a light fraction present in biodiesel derived from palmist oil and copra oil (Ballerini and Alazard-Toux, Les biocarburants; IFP Publications: Paris, 2006). The experimental data (P–T) were smoothed using the Antoine equation and compared with the available literature values. The molar enthalpies of vaporization at the mean temperature of the experimental range were derived from the Clausius–Clapeyron equation. From these results the standard enthalpies of vaporization at T = 298.15 K were calculated.

Vapor−liquid equilibria of two compounds, glycerol (or 1,2,3-propanetriol) and 1,3-propanediol, and two mixtures, glycerol + water and glycerol + 1,3-propanediol, were determined using a static apparatus. The obtained pressure values range from 6 Pa to 45 kPa for the compounds and from (32 to 163) kPa for the mixtures. From the temperature dependence of the vapor pressures, the molar enthalpies of vaporization at the mean temperature of the experimental range were derived from the Clausius−Clapeyron equation. From these results the standard enthalpies of vaporization at T = 298.15 K were calculated. The experimental data of the mixtures were correlated using the nonrandom two-liquid (NRTL) model. ■ INTRODUCTIONPetroleum reserves reduction and the increase of environmentally friendly comportment promote the development of new green energy research. Fatty acid methyl ester, commonly known as biodiesel, is derived from the triglyceride transesterification. The reaction generates glycerol as a byproduct in high quantities (1 mole of glycerol for every 3 moles of methyl esters synthesized, about 10 wt % of the total product). Glycerol valorization is crucial for the viability of biodiesel plant. One way for glycerol valorization could be its transformation in 1,3-propanediol which is a valuable chemical used in polyethylene and polyurethane production. 1−4 The development of the chemical processes (design and optimization) requires knowledge of physicochemical properties such as vapor pressures, the boiling point, and the vaporization enthalpy for all of the compounds and mixtures involved in the process. These data are often scarce or not available. So, predictive models such as the universal functional activity coefficient (UNIFAC) are largely used. 5,6 But when the systems present a weak nonideality the obtained results are not reliable. In this work, we were interested in the vapor pressures of two compounds and two mixtures, respectively: glycerol, 1,3-propanediol, water + glycerol, and 1,3-propanediol + glycerol. Experimental results were fitted by the Antoine and Clapeyron equations and compared with the available literature data. The two mixtures were correlated using the nonrandom two-liquid (NRTL) equation. ■ EXPERIMENTAL SECTIONMaterials. Glycerol (or 1,2,3-propanetriol) and 1,3-propanediol were purchased from Aldrich. Their purity was 99 %. Ultrapure water with a resistivity of 18 MΩ·cm, obtained with a Milli-Q system, was used.Apparatus and Procedure. Vapor pressure measurements were carried out using two static apparatuses: "low pressure" and "middle pressure" measurement apparatuses. The low pressure apparatus has been described in several articles, and the details of the experimental procedure can be found elsewhere. 7,8 Shortly, the apparatus is equipped with a differential manometer from MKS, type 670 model 616A, and a Rosemount pressure sensor (model 1151 DPE 22S2). The measurement range of the apparatus is comprised between 0.5 Pa and 200 kPa for the pressure and between 233 K and 463 K for the tem...

In this study, we reported experimental vapor pressures of several amines presenting different molecular structures, 2-phenylethylamine, benzylamine, triethylamine and cis-2,6-dimethylpiperidine, using a static apparatus. The pressure range is comprised between 0.2 Pa and 75 kPa, and the temperature range is between (273 and 365) K. From the temperature dependence of the vapor pressures, the molar enthalpies of vaporization at the mean temperature of the experimental range were derived from the Clausius−Clapeyron equation. From these results, the standard enthalpies of vaporization at T = 298.15 K were calculated and compared with the open literature values.