Liquid-liquid Equilibria of ([C2mim][EtSO4] + Thiophene + 2,2,4-Trimethylpentane) and ([C2mim][EtSO4] + Thiophene + Toluene): Experimental Data and Correlation

Liquid + liquid equilibrium data for (1-ethyl-3-methyl imidazolium ethyl sulfate + thiophene + 2,2,4-trimethylpentane) and (1-ethyl-3-methyl imidazolium ethyl sulfate + thiophene + toluene) have been determined at 298.15 K and atmospheric pressure. The ionic liquid has a great capacity to dissolve not only thiophene but also the toluene, being practically immiscible with 2,2,4-trimethylpentane. Equilibrium data of systems with toluene have been fairly well correlated with the NRTL and UNIQUAC equations but for the system with 2,2,4-trimethylpentane high deviations have been found with both equations.     

CeO2-Y2O3涂层和负载型Pd催化剂催化燃烧VOCs

制备了一种粘附在堇青石蜂窝陶瓷载体上的CeO_2-Y_2O_3(CeY)复合氧化物新涂层.以二氧化铈和柠檬酸钇为前驱体,制备过程中无有害物质产生,对环境友好.CeY涂层和Pd/CeY催化剂通过SEM、EDX、XRF和Raman光谱等表征.结果表明,此涂层的粘结强度高,对活性组分的吸附性能好,适合用来负载钯催化剂.Y_2O_3大部分进入了峰窝陶瓷的孔道内,CeO_2和Pd物种则富集在载体的表面.以CO、甲苯和乙酸乙酯的催化燃烧来评价Pd/CeY催化剂的性能,此催化剂具有较好的催化活性和热稳定性.500℃焙烧的催化剂,CO、甲苯和乙酸乙酯的T_(99)(转化率99%以上所需的最低反应温度)分别为150、220和310℃;1050℃焙烧的催化剂,它们的T_(99)分别为180、250和330℃.高温焙烧的催化剂,活性物种PdO的晶粒增大,这可能导致催化剂的活性下降.     

Volumetric Properties of Toluene with Ethyl Acrylate, Butyl Acrylate, Methyl Methacrylate, and Styrene at 25°C

Densities of the binary systems of toluene with ethyl acrylate, butyl acrylate, methyl methacrylate, and styrene have been measured as a function of the composition, at 25°C and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densitometer. The calculated excess volumes were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. The excess volumes are negative for systems toluene + (ethyl acrylate, butyl acrylate, and styrene) and positive for the system toluene + methyl methacrylate.     

气相色谱法分离和测定溶剂型木器涂料中正丁醇与苯系物

在气相色谱法测定溶剂型木器涂料中正丁醇及苯系物(包括苯、甲苯及二甲苯)时采用了VF-200MS型号的毛细管色谱柱。由于此型号的毛细管柱具有较强极性,不仅能达到正丁醇与苯系物之间的有效而满意的分离,而且还能使苯系物(包括苯、甲苯、乙苯、二甲苯)之间和二甲苯的同分异构体之间的有效分离。测定中采用正戊烷作内标和用火焰离子检测器检测。此方法的检出限(2S/N)在1.7~3.5 ng之间。用一含有正丁醇的硝基漆样品按所提出的方法进行多次重复测定,并在此样品的基础上加入各被测化合物的标准后进行测定,从而对方法的回收率和精密度作了测试,测得其回收率在87.8%~100.0%之间,测定值的相对标准偏差(n=6)均小于2.5%。     

Small-angle neutron scattering of dilute polystyrene chains at the protein limit of a colloid-polymer mixture

The present work investigates the structure of large polystyrene (PS) chains in solutions of small poly(ethyl methacrylate) (PEMA) microgel particles in toluene. Toluene is a good solvent for the PS chains. The PEMA colloids have an outer radius of R=11 nm which is much smaller in size than the radius of gyration Rg=58 nm of the PS chains. The system is considered to represent the protein limit of polymer-colloid mixtures. Structural investigation is performed by small-angle neutron scattering (SANS) using an appropriate contrast matching. This could be achieved by dissolving fully deuterated PS chains (D8-PS) in solutions of hydrogenated PEMA colloids in hydrogenated toluene (H-toluene). It is first demonstrated that PEMA colloids are satisfactorily contrast matched for SANS in H-toluene if the PEMA concentration does not exceed 200 g/l. Based on these findings, D8-PS is investigated by SANS in pure H-toluene and three different PEMA concentrations in H-toluene. The results indicate a drastic shrinking of D8-PS chain dimensions with increasing PEMA content. Comparison with model curves of star-branched Gaussian chains and Gaussian rings suggest a striking similarity of the respective density-density correlation of those models with the shrunken D8-PS chains. Along with this, a shrinking as large as 0.5 was estimated when the PEMA content reached 200 g/l.     

Isobaric (vapour+liquid) equilibria data for the binary systems (toluene+acetic acid) and (toluene+methyl ethyl ketone) at atmospheric pressure

Isobaric vapour–liquid equilibrium data have been measured for the binary systems toluene (1) + acetic acid (2) and toluene (1) + methyl ethyl ketone (2) at atmospheric pressure. An all-glass Fischer–Labodest-type apparatus, capable of handling pressures from 0.25 to 400 kPa and temperatures up to 523.15 K was used. The data were correlated by means of the NRTL, UNIQUAC, WILSON models and the applied UNIFAC model with satisfactory results; the relevant parameters are given and results were tested with regard to thermodynamic consistency using the methods of a modified Redlich–Kister and Herington equations.     

Adsorption of toluene-soluble polymers at the toluene–water interface

The adsorption of several toluene-soluble polymers at the toluene–water interface has been investigated by using the duNouy ring method of measuring interfacial tension γT /W . Polystyrene and poly(ethylene-co-vinyl acetate) (11.1 mole-% vinyl acetate) have little affinity for this interface at 29°C, but poly(methyl methacrylate) (PMMA) (M?_n = 420,000) and ethyl cellulose (EC) (M?_n = 50,100; 49.1% ethoxyl) adsorb significantly at concentrations as low as 1.0 × 10^?4 g/100ml. A plot of interfacial tension lowering versus initial logarithm of initial bulk phase polymer concentration is linear from 1.0 × 10^?4 to 1.0 × 10^?1 g/100 ml for EC and 1.0 × 10^?4 to 1.0 × 10^?2 g/100 ml for PMMA. When the PMMA concentration increases to 1.15 × 10^?1 g/100 ml, its adsorption behavior changes markedly. Prolonged time effects occur and adsorption becomes dependent upon dissolved water content of the toluene prior to formation of the toluene/water interface. Such effects are not observed with the other solutions studied. Increasing temperatures have variable effects on values of γT /W for the polymer solutions studied. Experiments with various polymer mixtures indicate that the polymer lowering T /W the most is preferentially adsorbed at the toluene–water interface and rapidly displaces less strongly adsorbed polymers.     

Thermodynamics of molecular interactions in ethyl iodide+toluene mixtures

The excess Gibb's free energy of mixing, G^E, for ethyl iodide+toluene at 25°C have been obtained from the measured vapor pressuure data. The H^E and G^E values for ethyl iodide+toluene are positive throughout the ethyl iodide concentration range and G^E>H^E. The results have been analyzed in terms of Flory and ideal associated model theory of nonelectrolyte solutions. It has been observed that the ideal associated model approach which assumes the presence of AN and A₂B molecular species describes well (within±10 J-mol^–1 in the worst case) the general dependence of H^E on X_A (mole fraction of ethyl iodide) over the whole composition range for ethyl iodide+toluene mixtures. The equilibrium constants for A+A AB and 2A+BA₂B reactions along with the enthalpies of formation of AB and A₂B molecular species have been calculated.     

Equilibrium desorption isotherms of water,ethanol, ethyl acetate,and toluene on a sodium smectite clay

Desorption isotherms for water, ethanol, ethyl acetate and toluene from a sodium smectite clay have been determined by both dynamic vapor sorption (DVS) measurements and Knudsen thermogravimetry (KTGA), at the exception of toluene that was measured only by the DVS method. The results obtained using these two methods were in satisfactory agreement, providing reliable insight into the desorption process, with certain lack of precision for ethyl acetate. The observed desorption behaviour suggests a liquid like phase at high volatile load, and a sorbed state in which molecules interact with the counter ions, at low volatile contents. However, the isotherms for water determined at various temperatures nearly superposed when plotted as a function of water activity, indicating the strength of the interactions in the clay–water system to remain of the same order of magnitude as that in bulk water, consistent with previous ab initio calculations.     

Temperature influence on mixing properties of {ethyl tert-butyl ether (ETBE) + gasoline additives}

The densities and ultrasonic velocity of {ethyl tert-butyl ether (ETBE) + (benzene, toluene, ethylbenzene, isooctane, tert-butyl alcohol, and ethanol)} over the temperature range (288.15 to 323.15) K and atmospheric pressure, have been measured over the whole concentration range. The experimental excess volumes and deviation of isentropic compressibilities data have been analysed in terms of different theoretical models. The gathered data improve open literature related to gasoline additives, and help to understand the ETBE volumetric and acoustic trend into different chemical environment.     

Measurement of plasma vanillylmandelic acid by liquid chromatography with electrochemical detection

A liquid chromatographic method with electrochemical detection is described for measuring plasma 3-methoxy-4-hydroxymandelic acid (VMA). Plasma is deproteinized by gel filtration and VMA is extracted into ethyl acetate, which is evaporated. VMA is oxidized to vanillin, which is purified by toluene extraction and quantified by high-performance liquid chromatography. The recovery of VMA through the entire procedure is 52 +/- 10% (mean +/- S.D., n = 19). The plasma VMA concentration in healthy young volunteers varies between 4.39 and 14.6 ng/ml, a range that is in excellent agreement with data obtained with mass fragmentography.     

Concurrent esterification and N-acetylation of amino acids with orthoesters: A useful reaction with interesting mechanistic implications

The concurrent esterification and N-acetylation of amino acids has been studied with triethyl orthoacetate (TEOA) and triethyl orthoformate (TEOF). In a surprising finding, only 1 equiv of TEOA in refluxing toluene was necessary to convert l-proline and l-phenylalanine into the corresponding N-acetyl ethyl esters in good yield. The same transformation using TEOF was not effective. Stereochemical outcome and stoichiometric studies as well as structural variation of the amino acids in this reaction provided unexpected mechanistic insight.     

Formation of toluene by microorganisms from anoxic freshwater sediments

Summary In artificial anoxic lakewater that had been inoculated with anoxic lake sediment, toluene was liberated by microorganisms and accumulated in the water. Phenylalanine, phenyllactate and phenylpyruvate proved to be effective precursors. Media supplemented with phenylacetate developed toluene even in a shorter period of time than the other three compounds. 2-Phenylethanol, phenylacetaldehyde, and phenylacetic acid ethyl ester only weakly supported the formation of toluene. The effectiveness of benzaldehyde was very low, and cinnamate did not at all support the formation of toluene. The transformation of phenylalanine to toluene was complete and resulted in the formation of stoichiometric amounts. Labelling experiments with deuterated phenylalanine showed no loss of label in the toluene molecule and no dilution by unlabelled toluene. The experiments support the view that phenylalanine that has been liberated from proteinaceous matter by hydrolysis is degraded in anoxic hypolimnia of lakes and anoxic sediments of rivers only to the stage of toluene. This reaction is responsible for the accumulation of toluene in these environments.     

Tuning aggregation of microemulsion droplets and silica nanoparticles using solvent mixtures

The effect of solvent on stability of water-in-oil microemulsions has been studied with AOT (sodium bis(2-ethylhexyl)sulfosuccinate) and different solvent mixtures of n-heptane, toluene and dodecane. Dynamic light scattering DLS was used to monitor the apparent diffusion coefficient D(A) and effective microemulsion droplet diameter on changing composition of the solvent. Interdroplet attractive interactions, as indicated by variations in D(A), can be tuned by formulation of appropriate solvent mixtures using heptane, toluene, and dodecane. In extreme cases, solvent mixtures can be used to induce phase transitions in the microemulsions. Aggregation and stability of model AOT-stabilized silica nanoparticles in different solvents were also investigated to explore further these solvent effects. For both systems the state of aggregation can be correlated with the effective molecular volume of the solvent V(mol)(eff) mixture.     

On the difficulties of predicting the adsorption of volatile organic compounds at low pressures in microporous solid: the example of ethyl benzene

Adsorption isotherms of toluene and ethyl benzene, at 25 degrees C and 40 degrees C, were determined in two microporous activated carbons and one zeolite. Significant differences were found in the adsorption behavior, at low pressures, between the two vapors on the same adsorbent material. The quantities of adsorbed ethyl benzene at 25 degrees C, in the low-pressure region, were lower than what was observed at 40 degrees C in all the studied adsorbents, contrary to what was found for toluene. This fact was not related to kinetic effects at the two temperatures nor to vapor swelling of the adsorbents structure. Also, there was no molecular sieving since at high pressures the toluene and ethyl benzene occupied the same adsorption space. The differences found in the ethyl benzene adsorption at the two temperatures pose difficulties in the analysis of the adsorption data and, therefore, in the prediction of results. This is discussed in the analysis of the results with the application of the Dubinin-Astakhov equation and in the estimation of the isosteric heats of adsorption. The adsorption potentials of two possible ethyl benzene conformations were estimated for the adsorption in the pores of activated carbon from the Horvath and Kawazoe model, and the values compared with those found experimentally. The results were interpreted in terms of the ethyl benzene conformation effects when the molecule is confined in pores that are about the same size of one of the conformations.     

SiO2-Al2O3玻纤载体负载CuO-CeO2对挥发性有机化合物催化燃烧性能研究

采用等体积共浸渍法制备了CuO-CeO₂整体式催化剂,评价了催化剂对乙酸乙酯、异丙醇及甲苯的催化燃烧性能。采用N₂吸附-脱附、X射线衍射（XRD）、氢气程序升温还原（H₂-TPR）、氨气程序升温脱附（NH₃-TPD）以及挥发性有机化合物脱附等手段对催化剂进行了表征。表征数据显示,氧化铜以高分散态均匀分散存在于载体表面,氧化铈则是小的纳米颗粒,氧化铈颗粒粒径随着Cu/Ce物质的量比的减小而增大。添加铈氧化物会显著增加总酸量,特别是路易斯酸酸位的量,同时增强了乙酸乙酯和异丙醇的吸附量,吸附量的增加提高了催化剂对乙酸乙酯和异丙醇的催化燃烧性能。从甲苯的催化燃烧实验可以看出,大量添加CeO₂稍微增加了甲苯的吸附容量,减弱了催化剂的还原性、降低了活性氧的含量,最终导致甲苯的低转化率。催化行为由氧化铜、氧化铈以及载体三者之间的共同作用决定,这三者的协同作用不仅影响着表面氧的活性同时影响着催化剂对甲苯的吸附能力。     

两种新型有机激光染料的合成、结构和上转换 发光性质

合成了两个新的有机晶体：反式-4-[4'-(N-羟乙基-N-甲基胺基)苯乙烯基]-N-甲基吡啶对甲苯磺酸盐trans-4-[4'-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridiniumtoluene-p-sulfonate(简称HMASPS)和反式-4-[4'-(N-羟乙基-N-乙基胺基)苯乙烯基]-N-甲基吡啶对甲苯磺酸盐trans-4-[4'-(N-hydroxyethyl-N-ethylamino)styryl]-N-methylpyridiniumtoluene-p-sulfonate(简称HEASPS)。用X射线衍射方法对这两个单晶进行了结构测定。测试了它们频率上转换荧光及激光性质。在1064nm的ps脉冲激光的激发下,HMASPS和HEASPS在溶液中均发出～625nm的上转荧光和激光,并且有可观的激光效率。     

Concentration dependences of the critical temperatures of binary mixtures of nonaqueous components

The critical (liquid-vapor) temperatures were determined by the ampule method for 10 binary mixtures containing aliphatic alcohols, n-octane, n-decane, methyl ethyl ketone, benzene, and toluene in various combinations. The predictive potential of several calculation methods was considered. The methods using binary interaction parameters as functions of the ratio between the critical volumes of compounds were found to correctly describe experimental data.     

Palladium-catalysed regioselective addition reaction of ethyl phenylphosphinate with terminal acetylenes: ligand- and solvent-dependent regioselectivity

Palladium-1,2-bis(diphenylphosphino)ethane complex catalyses regioselective Markovnikov addition of ethyl phenylphosphinate to terminal alkynes in toluene, while the use of tri-tert-butylphosphine as the ligand or ethanol as the solvent leads to regioselectivity reversal.     

Triphenylphosphine-Mediated Synthesis of the E/Z Isomers of Methyl 6-(1,2-Di(methoxycarbonyl))-8-(ethyl Carbamoylformyl)-2-oxo-2H-chromene-4-carboxylate

Triphenylphosphine-mediated reaction of dimethyl acetylenedicarboxylate with ethyl (2-hydroxyphenylcarbamoyl)formate in boiling toluene produces a mixture of methyl 8-(ethyl carbamylformyl)-2-oxo-2H-chromene-4-carboxylate and the E/Z isomers of methyl 6-(1,2-di(methoxycarbonyl)-8-(ethyl carbamoylformyl)-2-oxo-2H-chromene-4-carboxylate in moderate yields.