Influence of solvent mixtures on HPMCAS-celecoxib microparticles prepared by electrospraying

Hypromellose acetate succinate(HPMCAS) microparticles containing the poorly-water soluble drug celecoxib(CEL) were prepared by electrospraying intended for oral drug delivery. Various solvent mixtures with different solubility for CEL and HPMCAS were used to induce changes in the polymer structural conformation of the microparticles. The performance of the prepared microparticles was evaluated by studying the solid state from, particle size and morphology, radial drug distribution and drug release. CEL was amorphous in all electrosprayed HPMCAS microparticles. The particle size and morphology was dependent on the solubility of HPMCAS in the solvent mixture used with poorer solvents resulting in smaller microparticles with rougher appearance. The CEL distribution on the particles surface was relatively homogeneous and similar for all microparticles. Drug release from the microparticles was observed at a higher rate depending on the solubility of HPMCAS in the solvent used for electrospraying, and in all cases an at least 4-fold higher rate was observed compared with the crystalline drug. Drug precipitation from the supersaturated solution was inhibited by HPMCAS for all microparticles based on its parachute effect while crystalline CEL did not reach supersaturation. This study demonstrated that electrospraying can be used to produce microparticles with tailored properties for pharmaceutical application by adjusting solvent selection.

Phase behavior of heavy oil-solvent mixture systems under reservoir conditions

A novel experimental procedure was proposed to investigate the phase behavior of a solvent mixture(SM)(64 mol%CH4,8 mol%CO2,and 28 mol%C3 H8)with heavy oil.Then,a theoretical methodology was employed to estimate the phase behavior of the heavy oil-solvent mixture(HO-SM)systems with various mole fractions of SM.The experimental results show that as the mole fraction of SM increases,the saturation pressures and swelling factors of the HO-SM systems considerably increase,and the viscosities and densities of the HO-SM systems decrease.The heavy oil is upgraded in situ via asphaltene precipitation and SM dissolution.Therefore,the solvent-enriched oil phase at the top layer of reservoirs can easily be produced from the reservoir.The aforementioned results indicate that the SM has promising application potential for enhanced heavy oil recovery via solvent-based processes.The theoretical methodology can accurately predict the saturation pressures,swelling factors,and densities of HO-SM systems with various mole fractions of SM,with average error percentages of1.77%for saturation pressures,0.07%for swelling factors,and 0.07%for densities.

Determination of physical properties for the mixtures of [BMIM]Cl with different organic solvents

Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of l-butyl- 3-methyl imidazolium chloride （[BMIM]CI） and different organic solvents at 298.15 K have been investigated. Ex- cess molar volumes have been calculated and obtained data has been fitted by the Redlich-Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]CI, however, excep- tions do exist as in the case of dimethyl sulfoxide （DMSO）/[BMIM]CI. For DMSO/[BMIM]CI, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in all mixtures studied. It has been observed that solubility parameters, dielectric constants and composition of the solvents used play a vital role in determining the resultant properties. The data obtained will play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.

Crystal Growth of Calcite at Conditions of Gas Processing in Solvent Mixtures of Monoethylene Glycol and Water

Growth kinetics of the most stable polymorph of calcium carbonate,calcite,has been studied in seeded stirred batch experiments in MEG-water solutions at 40 ℃ and 70 ℃,conditions relevant for the processing of natural gas.It was found that MEG changes the growth order from two in pure water to one in solvent mixtures of MEG and water.Assuming parabolic growth (growth order is equal to two),it could be shown that MEG decreases the growth rate constant for calcite from 0.52 nm/s to 0.11 nm/s (70 ℃) when the MEG-content is increased from 0 wt% MEG to 65 wt% MEG.Decreasing the temperature from 70 ℃ to 40 ℃ has a similar effect on the growth rate constant as raising the level of MEG to 65 wt%.

Water Sorption Behaviors of Novel Biohybrid Hydrogels as Effective Sorbents in Water-Solvent Binary Mixtures

Novel sorbent hydrogels containing acrylamide/sodium vinylsulfonate, carboxymethyl cellulose and zeolite were synthesized with free radical solution polymerization by using ammonium persulfate/N,N,N’,N’-tetramethylethyle-nediamine as redox initiating pair in presence of poly(ethylene glycol) diacrylate as crosslinker. It was to investigate the water uptake properties of series of the novel hydrogels, the semi IPNs and the hybrid/biohybrid composite hydrogel sorbents synthesized in this study. Water uptake studies were performed in water and in water-solvent (acetone, methanol and tetrahydrofuran) binary mixtures at 25°C, gravimetrically. Some swelling and diffusion parameters were calculated and discussed. It has been seen that the lower equilibrium swelling factor values in all solvent compositions in comparison with the equilibrium swelling factor values in water.

Low-melting mixture solvents:extension of deep eutectic solvents and ionic liquids for broadening green solvents and green chemistry

Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast development in the past two decades.In this contribution,DESs are reviewed critically and the concept is extended to lowmelting mixture solvents(Lo MMSs),which cover all kinds of materials including ionic compounds,molecular compounds,and metals.Six classes of Lo MMSs are proposed as the new classification system and examples are given.Finally,several thermodynamic issues concerning Lo MMSs are discussed.Two new concepts,robustness of Lo MMSs and high-entropy Lo MMSs,are proposed.

COSMO-RS模型在离子液体/低共熔溶剂筛选中的应用研究进展

离子液体(ILs)和低共熔溶剂(DESs)作为一类新型的绿色溶剂,由于其独特的物理化学性质,在混合物分离方面已经受到了研究者的广泛关注,因此逐渐成为绿色化学领域的研究重点。针对特定的分离过程,选择合适的溶剂是非常重要的,然而,由于ILs和DESs种类较多,结构复杂,通过实验的方法逐一进行筛选费时费力、成本高,且几乎不可能找到最优选择,因此应用理论计算模型对ILs和DESs进行筛选是非常有必要的。真实溶剂类导体屏蔽模型(COSMO-RS模型)是一种由量子化学计算与统计热力学方法相结合的预测模型,它可以在不需要实验数据的情况下预测液体混合物的热力学性质,已经被研究者广泛用作各种分离问题的快速筛选工具。整理了应用COSMO-RS模型筛选ILs/DESs用于各种油中酚类、含氮化合物、含硫化合物、萜类化合物、天然维生素E的萃取分离,以及CO_(2)捕获和共沸混合物等的分离过程,表明COSMO-RS模型用于特定混合物萃取溶剂的筛选是快速有效的,可为难分离混合物分离过程中ILs/DESs的预筛选提供有价值的参考。

Thickness Uniformity Adjustment of Inkjet Printed Light-emitting Polymer Films by Solvent Mixture

In this paper, thickness uniformity of poly（9,9-di-n-octylfluorene） films patterned by inkjet printing was im- proved by the use of solvent mixtures （a solvent with higher volatility, higher surface energy and lower viscosity, with another solvent with lower volatility, lower surface energy and higher viscosity）. The average thickness of inkjet printed poly（9,9-di-n-octylfluorene） films was increased from ca. 30 nm to ca. 100 nm when solvent mixtures were used instead of pure chlorobenzene. More flat PFO films were formed instead of the original films with con- cave-lens like cross-section formed by coffee ring effect. This improvement was explained by combination of in- tense Marangoni flow at early drying process and weak complementary flow at the later drying process formed in the solvent mixture. Patterned poly（9,9-di-n-octylfluorene） films were used for fabrication of electroluminescence devices with improved electronic property. Array of pixels with about 80% effective light-emitting area was ob- tained.

混合二元酸结晶分离技术研究进展

混合二元酸(DBA)中戊二酸(GA)、丁二酸(SA)、己二酸(ADA)均具有较高的市场价格和应用价值,对DBA进行分离提纯可获得高额附加值。介绍了DBA的分离方法,系统对比了DBA结晶分离GA、SA技术中,水、混合芳烃、正丁醇等溶剂体系的特点及该体系下操作控制参数、结晶方式等技术研究进展,提出了技术改进方向,为DBA的资源化、高附加值利用提供了参考。

Design of solvent mixtures for removal of phenol from wastewater using a non-linear programming model with a multi-start method

The optimization-based design of solvent mixtures used for phenolic wastewater treatment was investigated in this work.A nonlinear programming(NLP)model was formulated based on the concepts of computer-aid molecule design(Computer-Aided Molecular Design,CAMD)to select solvent mixtures with the best extraction performance considering the constraints of extraction process and the environmental impact.Due to the complexity of the NLP model,multi-start method was adopted to solve this problem in order to get near global optimal solution.The results of the calculations suggested that the optimal mixture consisted of 70.1%n-octanol and 29.9%2-octanone(molar fraction).The 119 sets of experimental results showed that the extraction ability of the optimal solvent mixture identified by CAMD technique was among the top 6 sets compared to the experiment results.The results suggested that the developed NLP model could be able to screen the optimal solvent mixture in phenolic wastewater treatment.

To gel or not to gel：A prior prediction of gelation in solvent mixtures

The gelation behaviours of low molecular weight gelators 1,3：2,5：4.6-tris（3,4-dichlorobenzylidene）-Dmannitol（G1） and 2,4-（3.4-dichlorobenzylidene）-N-（3-aminopropyl）-D-gluconamide（G2） in 34 solvents have been studied.We found that sample dissolved at low concentrations may become a gel or precipitate at higher concentrations.The Hansen solubility parameters（HSPs） and a Teas plot were employed to correlate the gelation behaviours with solvent properties,but with no success if the concentration of the tests was not maintained constant.Instead,on the basis of the gelation results obtained for the G1 and G2 in single solvents,we studied the gelation behaviours of G1 and G2 in23 solvent mixtures and found that the tendency of a gelator to form a gel in mixed solvents is strongly correlated with its gelation behaviours in good solvents.If the gelation occurs in a good solvent at higher concentrations,it will take place as well in a mixed solvent（the good solvent plus a poor solvent） at a certain volume ratio.In contrast,if the gelator forms a precipitate in a good solvent at higher concentrations,no gelation is to be observed in the mixed solvents.A gelation rule for mixed solvents is thus proposed,which may facilitate decision making with regard to solvent selection for gel formation in the solvent mixtures in practical applications.

Polymer Solar Cells with Improved Power Conversion Efficiency Using Solvent Mixtures

In this paper, the effects of solvent mixtures on the morphology, charge transport, and light trapping of poly[N-900-hepta-decanyl-2,7-carbazole-alt-5,5-（40,70-di-2-thienyl-20,10,30-benzothiadiazole）]（PCDTBT） and [6,6]-phenyl C71-butyric acid methyl ester（PC71BM） based solar cells were investigated. As a good solvent for PCDTBT, o-dichlorobenzene（ODCB） was selected to mix with chloroform（CF）, chlorobenzene（eB）, and 1,2,4-Trichloroben-zene（TCB） for optimizing the morphology of the PCDTBT：PCTIBM active layer. It can be found that the device performance of polymer solar cells（PSCs） has been greatly improved when using a optimal blend ratio. Especially, the PSCs fabricated via ODCB（90%）/CF（10%, volume fraction） mixture exhibit a remarkable enhancement of photon-to-current efficiency（PCE） from 5.16% to 7.47%. The enhanced performance of the PSCs can be attributed to the higher absorption, the lower resistance, and the optimized surface morphology of the active layers modified by the solvent mixtures.

用NRTL方程计算含离子液体体系的汽液平衡

离子液体作为环境友好溶剂在反应和分离过程中具有良好的应用前景, 含离子液体体系汽液平衡的计算及模型化研究具有重要的理论和实际意义. 采用非电解质溶液NRTL 方程表示溶液的非理想性, 关联了[bmim] [PF6] H2O及[C8mim] [PF6] H2O二元体系的等温汽液平衡, 关联误差在2%之内; 预测了这些体系在其他温度下的汽液平衡, 预测的总平均误差均在5%之内. 通过关联不同温度下有机物在离子液体C8H14S2O4F6N3 和C9H16S2O4F6N3 中的无限稀释活度因子的实验数据, 得到了有关NRTL方程的二元作用参数, 在此基础上预测了离子液体对二元共沸体系汽液平衡的影响. 结果表明, 含离子液体体系的汽液平衡可以采用传统的非电解质溶液模型如NRTL方程来描述, 离子液体的“盐效应”可以显著改善组分的相对挥发度甚至消除共沸现象.

H_2ODMSO混合溶剂对丙烯腈与N-乙烯基吡咯烷酮共聚反应的影响

为得到高性能的聚丙烯腈原丝,采用H2O DMSO(二甲基亚砜)混合溶剂工艺合成了丙烯腈(AN)与N 乙烯基吡咯烷酮(NVP)共聚物。探讨了H2O DMSO混合溶剂对丙烯腈(AN)与N 乙烯基吡咯烷酮(NVP)共聚反应动力学的影响,计算了聚合反应表观活化能,并对共聚物进行了GPC元素分析、IR分析。结果表明:随混合溶剂中DMSO含量的增多,聚合反应速率降低,分子量降低且分布变宽,聚合物立构规整性变差;利用Kelen Tudos法测定出单体竞聚率:rAN=0.656±0.015,rNVP=2.11±0.18。在H2O DMSO=80 20(质量比),t=60℃条件下可得到适合纺丝的共聚物。

水复合溶剂体系茴脑臭氧化反应合成茴香醛新工艺

以茴脑为原料,有机溶剂与水复合溶剂为溶剂,室温下通过臭氧化分解反应制取茴香醛,并通过GC-MS、FT-IR和1H-NMR对产品进行了表征。对该溶剂体系与传统溶剂体系下茴香醛的产率进行了对比,并确定了丙酮/水体系为最佳溶剂体系。实验详细考察了溶剂用量、臭氧气流量、混合溶剂中水含量和反应时间等工艺参数。优化的工艺条件为:丙酮和水为溶剂,m(茴脑):m(混合溶剂)=1:3,臭氧气流量0.06 m3 h 1,混合溶剂中水的质量含量为15%,反应时间100 min,茴香醛产率82.70%。该反应在水的存在下实现了室温下一步法合成茴香醛,避免了茴脑臭氧化物的分离及还原步骤,工艺简单,洁净环保。

逆电渗析法热-电转换系统循环工质匹配准则

将开式逆向电渗析法浓差能发电技术原理与吸收式制冷/热泵系统循环原理相结合,提出了一种全新的闭式热-电循环转换方法,且发现工作介质(溶质与溶剂混合物)是影响该系统能量转换效率的关键因素之一。以9种溶质(一价无机盐)和17种溶剂(标准沸点温度在40~150℃)为研究对象,通过分析工质的13项关键物性参数(沸点温度、汽化潜热、比热容、溶解度、偏心因子、偶极矩、相对介电常数、电导率、黏度、热导率、燃爆极限、自动点火温度及毒性),建立了从热力学性质、电化学性质、输运特性、危险性等多角度来综合评价热-电循环转换系统工质匹配性的准则,并据此推断无机盐-溶解剂-调节剂三元混合物极具发展潜力。

低共熔法萃取分离油酚混合物过程中油的夹带

采用季铵盐与酚形成低共熔溶剂(DES)从含酚的混合物中萃取分离酚是一种有效的油酚分离方法,然而分离过程中,中性油的夹带会影响分离效率。以含苯酚200g·L-1的甲苯溶液作为模拟油酚混合物,氯化胆碱(ChCl)作为分离剂,研究了氯化胆碱的加入量、萃取温度(25~55℃)及模拟油中直链烷烃的浓度等因素对酚的萃取分离及中性油夹带的影响。结果表明,随着ChCl加入量增大,酚萃取率升高,中性油的夹带量减少;ChCl过量时,酚的萃取量恒定且达到极大值,中性油夹带量恒定且夹带量最小;萃取温度对酚的萃取率影响不大,对中性油的夹带量在ChCl加入量不足时随温度升高而增多,当ChCl加入量足量时与温度变化关系不大;模拟油中直链烷烃的浓度不影响萃取效率,浓度越高,甲苯夹带越少。以ChCl萃取含苯酚200g·L-1的甲苯溶液,在萃取温度25℃、ChCl加入量大于0.6(与酚的摩尔比)的条件下,苯酚萃取率达95%,甲苯夹带率为15%,70℃条件下氮气吹扫60min内可将DES中甲苯完全去除。

丙烯腈与N-乙烯基吡咯烷酮在H_2O/DMSO混合溶剂中共聚反应动力学研究

在水和二甲基亚砜(DMSO)混合溶剂中,以偶氮二异丁腈(AIBN)为引发剂,聚乙烯醇(PVA)为分散剂,合成了丙烯腈(AN)与N 乙烯基吡咯烷酮(NVP)共聚物,在反应温度为60℃时,建立了聚合反应速率方程Rp=kC0.651±0.123NVP ,求得聚合反应的表观活化能。并讨论了AN C1.17±0.14AIBN C1.59±0.35添加剂对苯二酚和二氧杂环己烷对共聚反应的影响。

溶剂-非溶剂法制备混合点火药

通过对目前点火药制备工艺的分析,选择了溶剂非溶剂法制备混合点火药。确定了制备混合点火药的工艺流程,并对所制备点火药的形貌和热性能进行了分析。结果表明:采用该工艺制备的药剂颗粒近似球形,流散性好;制备的混合点火药的安定性得到增强。