反气相色谱法测定有机溶剂型木质素的溶解度参数

采用反气相色谱法(IGC),于333.15～373.15 K温度范围内测定了有机溶剂型木质素的溶解度参数(δ2)及相关指标。以正辛烷(n-C8)、正癸烷(n-C10)、正十二烷(n-C12)和正十四烷(n-C14)为探针溶剂,计算了探针溶剂的特性保留体积(V0g)、摩尔吸收焓(ΔHs1)、无限稀释摩尔混合焓(ΔH∞1)、摩尔蒸发焓(ΔHv)、无限稀释活度系数(Ω∞1)以及探针溶剂与有机溶剂型木质素的Flory-Huggins相互作用参数(χ∞12)。结果表明,上述4种探针溶剂在测定的温度范围内均为有机溶剂型木质素的不良溶液;在同一温度下,参数χ∞12随着探针溶剂碳数的增加而降低。测得的有机溶剂型木质素的δ2为19.03 (J\5cm-3)1/2。     

Homogeneous catalysis,heterogeneous recycling: a new family of branched molecules with hydrocarbon or fluorocarbon chains for the Friedländer synthesis of quinoline under solvent-free conditions

A new family of branched catalysts with hydrocarbon or fluorocarbon chains was used to catalyze Friedländer reaction between 2-aminoarylketones and α-methylene ketones under solvent-free conditions in good to excellent yields. The catalysts exhibit temperature-dependent solubility and such a thermomorphic character allows them to be recovered by filtration conveniently at room temperature and reused at least five times. To some extent, the branched catalysts with hydrocarbon chains are superior to those with fluorocarbon chains, as they are cheaper and more biodegradable.     

Fully imidized soluble polyimides based on a novel dianhydride: 2,2′-dichloro-4,4′,5,5′-benzophenone tetracarboxylic dianhydride

We have synthesized a novel dianhydride, 2,2′-dichloro-4,4′,5,5′-benzophenone tetracarboxylic dianhydride (DCBTDA). Polyimides were synthesized with DCBTDA or 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and several relatively rigid meta- and para- substituted mononuclear diamines. The BTDA based systems were insoluble in dipolar, aprotic solvents whereas the DCBTDA based polymers displayed enhanced solubility in these solvents. The thermal stability of these polyimides was excellent as measured by 5% weight loss decomposition. The T_g's of the polymers were all above 290°C.     

A convenient preparative method for anionic tris(substituted pyrazolyl)methane ligands

The synthesis of tris[3-(6-carboxypyridin-2-yl)pyrazol-1-yl]methane is described in a linear multi-step protocol. The pyridyl-pyrazolyl arms are first constructed before being condensed with chloroform. Careful study of the condensation reaction shows the presence of an isomeric form of the tris(pyrazolyl)methane derivative in which one of the pyrazolyl substituents is linked through the nitrogen atom at the 2 position of the pyrazol. After acid-catalysed isomerisation to the desired isomer, the intermediate compound was subjected to a carboalkoxylation reaction and a subsequent hydrolysis. These are some rare examples of reactions directly occurring on the tris(pyrazolyl)methane platforms.     

不同浓度KCl和NH4Cl溶液中H3BO3介稳区的性质

测定了H3BO3在0~25 ℃内于不同浓度KCl和NH4Cl溶液中的溶解度和超溶解度, 得到了H3BO3的介稳区宽度, 并推算出表观成核级数m, 给出了成核速率方程. 研究了KCl和NH4Cl对H3BO3介稳区性质的影响, 并对影响的机理进行了探讨. 结果表明, KCl使H3BO3介稳区向低温方向移动; NH4Cl使H3BO3介稳区向高温方向移动; 根据所得结论分析了KCl和NH4Cl在柴达木西部油田水析硼过程中的影响, 认为KCl和NH4Cl在蒸发过程中浓度的变化是造成硼分散析出而不能富集的因素之一.     

Structural modification of BODIPY: Improve its applicability

BODIPY has been considered a potential scaffold because of their neutral total charge, sharp absorption,and emission with high fluorescence quantum yield. However, the drawback of emission wavelength at less than 600 nm and hydrophobicity limit its application. One of the extremely interesting properties of BODIPY is that small modifications to their structures could be able to tune their properties, mainly including the absorption/emission wavelength and the hydrophilicity. This review focuses on the modification at different positions of BODIPY to improve the water-solubility and emission wavelength that describe their spectral, photophysical properties and applicability, which is helpful for the researchers to rationally design BODIPY dyes to adapt a wide range of applications.     

对称四甲基取代六元瓜环对醋酸地塞米松的增溶作用

利用微孔滤膜分离方法研究了对称四甲基取代六元瓜环(TMeQ[6])对醋酸地塞米松的增溶作用,并利用差热分析法(DTA)分析TMeQ[6]和醋酸地塞米松的包结物。结果表明,TMeQ[6]对醋酸地塞米松有一定的增溶作用,随TMeQ[6]浓度增大,醋酸地塞米松的溶解度呈增大趋势,当TMeQ[6]浓度从0.04mmol/L提高至0.28mmol/L增溶倍数可达4～17倍;当温度从10℃升至70℃,增溶倍数先下降然后趋于稳定。同时,还利用共溶剂法制备了TMeQ[6]与醋酸地塞米松的固体包结物,并对其主客体作用进行了DTA研究。     

Methane and carbon dioxide solubility in 1,2-propylene glycol at temperatures ranging from 303 to 423 K and pressures up to 12 MPa

This work reports solubility data of methane and carbon dioxide in 1,2-propylene glycol and the Henry's law constant of each solute in the studied solvent at saturation pressure. The measurements were performed at 303, 323, 373, 398 and 423.15 K and pressures up to 4.5 MPa for carbon dioxide solubility and pressures up to 12.1 MPa for methane solubility. The experiments were performed in an autoclave type phase equilibrium apparatus using the total pressure method (synthetic method). All investigated systems show an increase of gas-solubility with the increase of pressure. A decrease of carbon dioxide solubility with the increase of temperature and an increase of methane solubility with the increase of temperature was observed. From the variation of solubility with temperature, partial molar enthalpy and entropy change of the solute for each mixture were calculated.     

Solubilities of cinnamic acid esters in binary mixtures of ionic liquids and organic solvents

The solubilities of three cinnamic acid esters, namely, methyl ferulate, methyl p-coumarate, and methyl sinapate, have been measured in mixed solvent systems of tert-butanol with 1-butyl-3-methyl-imidazolium hexafluorophosphate ([BMIM][PF₆]), 1-butyl-3-methyl-imidazolium tetrafluoroborate ([BMIM][BF₄]) and 1-methyl-3-octyl-imidazolium tetrafluoroborate ([OMIM][BF₄]) at 303.15 and 321.15 K, and in mixed solvent systems of ethyl acetate with [BMIM][BF₄] and [OMIM][BF₄] at 303.15 K. In eight cases, out of the 22 data sets, an additive behaviour of the solubility was observed, positive deviations from additivity were observed in six cases, a positive synergistic effect in five cases, and, finally, negative deviations from additivity in the remaining three cases. Prediction of the solubilities of the solutes in the various ternary systems was performed with the NRTL and UNIQUAC activity coefficient models. The binary interaction parameters of the models between solute and solvent molecules were taken from the literature. When the parameters between the solvent molecules are fitted to literature data, satisfactory predictions are not always obtained. On the other hand, very good predictions are obtained when only one of the two interaction parameters between the two solvent molecules is fitted to one single point of the solubility isotherm and the other interaction parameter is set equal to zero.     

Prediction of hydrogen solubility in heavy hydrocarbons over a range of temperatures and pressures using molecular dynamics simulations

Using the method of molecular dynamics (MD), we have estimated the solubility of hydrogen in heavy hydrocarbons for a range of temperatures and pressures. Heavy hydrocarbon systems are known to be challenging not only for experimental measurements but also for reliable estimations using traditional equations of state (EOS). The simulation system used was designed with semi-permeable membranes to mimic actual experimental studies of gas solubility. Binary interaction parameters between the solute gas and the solvent (heavy hydrocarbons) components were adjusted when necessary to improve agreement with experimental results and then used in subsequent multi-component studies. Temperature and pressure ranges studied included higher temperatures and pressures which are especially difficult to investigate experimentally. Simulation results were finally used to adjust the binary interaction parameters (BIP) in simulation packages (e.g. Aspen) to enable quick and reliable predictions.