Supercritical CO2 and highly selective aromatase inhibitors: Experimental solubility and empirical data correlation

The solubility of highly selective and potent third-generation aromatase inhibitors includes the non-steroidal agents letrozole and anastrozole and the steroid exemestane in supercritical carbon dioxide (SC-CO₂) has been investigated. The experiments were carried out using the simple and static method at pressures in the range of 12.1–35.5 MPa and temperatures ranging from 308 to 348 K. The mole fraction solubilities ranged from 0.22 × 10⁻⁵ to 1.88 × 10⁻⁴. Solubility data were correlated using six empirical models (Chrastil model, dV–A model, K–J model, Bartle model, Yu model and Gordillo model). The results showed that these models can be applied to satisfactory solubility predictions at different pressures and temperatures. A comparison among the six models revealed that the K–J, and Gordillo models gave much better correlations of the solubility data with an average absolute relative deviation (AARD%) ranging from 0.2 to 2.3 and from 1.6 to 2.5%, respectively. Using the correlation results, the heat of drug–CO₂ solvation and that of drug vaporization was separately approximated in the range of −17.3 to −17.5 and 93.0–112.1 kJ mol⁻¹.     

Microporous polymelamine network for highly selective CO2 adsorption

Microporous polymelamine network was prepared through one-pot catalyst-free polymerization using the Schiff base reaction. Gas adsorption experiments indicate that the network possesses high CO₂ uptake capacity, reaching 89.0 cm³ g^?1 (17.9 wt%) at 1.0 bar and 273 K, along with high selectivity towards CO₂ over N₂ and CH₄. The porous polymeric network presents a promising potential as efficient adsorbents in clean energy applications.     

仲胺桥联共价三嗪聚合物对CO2的高选择性吸附

针对有机聚合物材料对CO2的吸附量和吸附选择性不能兼得的问题,由三(4-氰胺基苯基)胺和四(4-氰胺基苯基)甲烷设计合成了仲胺桥联共价三嗪聚合物NB-CTP-1和NB-CTP-2,通过FTIR、TGA、XRD、SEM、TEM和全自动物理吸附分析仪对制备的样品进行了结构和形貌表征.在1.01×105 Pa、273 K条件下,NB-CTP-1和NB-CTP-2的CO2吸附量分别为3.04和3.23 mmol/g.依据亨利定律法和IAST法分别对两种材料在1.01×105 Pa、273 K条件下的吸附选择性进行计算,其中,NB-CTP-1的CO2/N2吸附选择性高达113(亨利定律法)和143(IAST法),而NB-CTP-2也能达到75(亨利定律法)和89(IAST法).此外,通过Clausius-Clapeyron方程计算得出NB-CTP-1和NB-CTP-2的极限吸附热分别为35.3和37.6 kJ/mol,表明其与CO2存在较强的偶极-四极相互作用,有利于提升吸附选择性.     

超临界二氧化碳萃取大蒜油实验研究

建立了一套超临界流体萃取实验装置,系统研究了超临界二氧化碳萃取大蒜油的实验工艺,考察了萃取压力、萃取温度、流体流量以及原料厚度对大蒜油收率的影响,确定了各因素对萃取率指标影响的主次程度依次为:压力、流体流量、原料厚度、温度;确定了实验范围内的最佳萃取工艺条件为:压力25MPa、温度40℃、CO2流量0.3～0.4m3·h-1、大蒜厚度1～0.5mm。     

Modification of polystyrene properties by CO2: Experimental study and correlation

The sorption of CO₂ in polymers entails their swelling and plasticization whose study is crucial for the design of processes and further applications. The operating conditions during foaming, purification, or impregnation of polymers in CO₂ are mainly determined by the mentioned binary system. In this work, the modification of polystyrene's physical properties (glass transition temperature and viscosity) has been experimentally studied. Since plasticization phenomena are very valuable for the processing of polymers, the amount of CO₂ absorbed into the polymer is related with the changes in the described properties. Furthermore, interfacial tension is also correlated with the sorption of CO₂ from literature data. The proposed correlation fits pretty well the properties shifts in the studied working conditions. Finally, the influence of pressure and temperature on the diffusivity of the CO₂ in the polystyrene is calculated through the measurement of viscosity along time. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41696.     

The highly selective catalytic hydrogenation of CO2 to CO over transition metal nitrides

Three transition metal-like facet centered cubic structured transition metal nitrides, γ-Mo₂N, β-W₂N and δ-NbN, are synthesized and applied in the reaction of CO₂ hydrogenation to CO. Among the three nitride catalysts, the γ-Mo₂N exhibits superior activity to target product CO, which is 4.6 and 76 times higher than the other two counterparts of β-W₂N and δ-NbN at 600 ℃, respectively. Additionally, γ-Mo₂N exhibits excellent stability on both cyclic heating–cooling and high space velocity steady state operation. The deactivation degree of cyclic heating–cooling evaluation after 5 cycles and long-term stability performance at 773 and 873 K in 50 h are all less than 10%. In-situ XRD and kinetic studies suggest that the γ-Mo₂N itself is able to activate both of the reactants CO₂ and H₂. Below 400 ℃, the reaction mainly occurs at the surface of γ-Mo₂N catalyst. CO₂ and H₂ competitively adsorbe on the surface of catalyst and CO₂ is the relatively stronger surface adsorbate. At a higher temperature, the interstitial vacancies of the γ-Mo₂N can be reversibly filled with the oxygen from CO₂ dissociation. Both of the surface and bulk phase sites of γ-Mo₂N participate in the high temperature CO₂ hydrogenation pathway.     

超临界二氧化碳萃取生姜油实验研究与数值模拟

1 INTRODUCTION Supercritical fluid extraction (SFE) as an alter- native to conventional processes, such as solvent ex- traction and steam distillation for obtaining essential oils, is a novel technique especially attractive to the food, cosmetics and Pharmaceuticals industries. The extracts from SFE are free of solvent residues. In ad- dition, the process can be conducted at low tempera- ture, which is very important to preserve the quality of heat-sensitive products[1,2]. Ginger (Zing…     

枸杞籽油超临界二氧化碳萃取方法的实验研究

建立了一套超临界流体萃取枸杞籽油实验流程．以CO2为萃取剂,考察了萃取压力、操作温度、CO2流量及原料颗粒度等因素对枸杞籽油萃取率的影响,确定了较佳的萃取工艺条件：压力30MPa,温度313-318K,枸杞籽颗粒40-50目,CO2流量0．3—0．4m^3/h时枸杞籽油萃取率最高,可达155％.     

Accelerating CO2 capture of highly permeable polymer through incorporating highly selective hollow zeolite imidazolate framework

The implementation of high-performance membranes in large-scale CO₂ capture has the potential to significantly decrease the capture cost and reduce the environmental footprints. However, highly permeable polymers rarely have sufficient selectivity for energy-efficient carbon capture. In this study, zeolite imidazolate framework hollow nanoparticles (ZIF-HNPs) were synthesized and embedded into highly permeable polymers as versatile fillers to prepare mixed matrix membranes (MMMs). The interior hollow architecture minimizes transport resistance of gas diffusion through the fillers while its molecular-sieving shell provides high selectivity. With 28 vol% loading of ZIF-HNPs, the membrane exhibits CO₂ permeability of 7,128 Barrer and CO₂/CH₄ selectivity of 16.4 (57.7% and 31.4% higher than these of pristine membrane), which surpass the upper bound of the state-of-the-art reported polymeric membranes. Meanwhile, we proposed a modified Maxwell model based on the hierarchical structure of the MMM to analyze the effects of cavity size and loading on gas transport behaviors within membranes.     

超临界CO2萃取生姜油实验研究与数值模拟

利用自建的超临界流体萃取实验装置,以CO2为萃取剂,考察了萃取压力、温度、流体流量及原料颗粒度等因素对生姜油累积萃取率的影响,由此确定了较佳的萃取工艺条件。基于萃取器微分单元质量守恒原理,建立了数学模型,并利用直线推动力近似理论拟合了总传质推动力及平衡吸收常数,对实验结果进行了数值模拟。     

Experimental measurements and modeling of CO2 solubility in sunflower,castor and rapeseed oils

In this work solubility measurements of CO₂ in three vegetable oils, a high oleic sunflower oil (HOSO), a castor oil and a rapeseed oil, for mole fractions ranging from 0.32 to 0.93 in the temperature range 298–363 K and up to 75 MPa were performed. Moreover, the densities and viscosities of these oils are reported from 278.15 to 373.15 K at atmospheric pressure. These data were used to evaluate the predictive ability of the fragment based approach. Solubility data were modeled by means of the SRK EoS and predicted employing the Carvalho and Coutinho correlation. Global average deviations inferior to 6% in CO₂ mole fraction composition were achieved with the SRK EoS and maximum percentage absolute average deviations of 13% in pressure were obtained using the Carvalho and Coutinho correlation.     

Measurement and correlation solubility of cefixime trihydrate and oxymetholone in supercritical carbon dioxide (CO2)

The equilibrium solubilities of cefixime trihydrate and oxymetholone in supercritical carbon dioxide (CO₂) were measured using a “static method”. Cefixime trihydrate is a cephalosporin antibiotic drug and Oxymetholone is a 17alpha-alkylated anabolic-androgenic steroid drug. The experimental measurements for cefixime trihydrate were performed at temperatures of 308, 318 and 328 K as well as pressure range from 183 to 335 bar. The solubility of oxymetholone was determined at 308, 318 and 328 K and pressure range from 121 to 305 bar. The experimental solubility data (mole fraction) for cefixime trihydrate and oxymetholone was greater than 1.6 × 10⁻⁷ and 1.6 × 10⁻⁵ and less than 3.02 × 10⁻⁷ and 1.49 × 10⁻⁴, respectively. The solubilities for two drugs in CO₂ were correlated by using four semi-empirical models such as Bartle, Kumar and Johnstone (K–J), Mendez-Santiago and Teja (M–T) and Chrastil models. The results obtained from the semi-empirical models show that there is good agreement between the experimental data and the results of semi-empirical models. By using the correlation results, the heat of drug–CO₂ solvation and heat of drug vaporization for cefixime–CO₂ and oxymetholone–CO₂ systems may be approximately estimated. Also, the Peng–Robinson (PR) cubic equation of state (CEOS) along with the van der Waals combining rule was applied to correlate the drugs solubilities in supercritical CO₂. The average absolute deviation between the experimental data and the results of PR equation for cefixime trihydrate and oxymetholone was 11.92% and 11.74%, respectively.     

超临界CO2萃取工艺及装置

超临界流体萃取技术是近20年来国际上取得迅速发展的化工分离高新技术,在食品、香料、药物和化工等领域有着广泛的应用前景,并已取得一系列工业应用成果.在国内,历经十余年的实验研究和应用开发工作,超临界CO2萃取技术已从研究阶段逐步走向工业化,其应用前景受到广泛关注.     

超临界二氧化碳技术与绿色化工过程

介绍了超临界二氧化碳的有关知识,说明了它在萃取分离、反应分离、多相反应以及清除环境污染物中的重要作用。指出了其目前存在的问题并对其应用前景进行了展望。     

Supercritical extraction of sunflower seed oil: Experimental data and model validation

In this work experimental results of sunflower seed oil extraction using supercritical CO₂ are presented, together with the outcome obtained by applying to the same data a theoretical model recently developed and further improved here.We performed extraction tests utilizing a supercritical extraction equipment having a volumetric capability of 100 ml; the seeds were milled to obtain different particle sizes (mean diameter between 0.19 and 1.2 mm); the range of pressure investigated was 280–550 bar, the temperature and solvent flow rate were maintained constant at about 40 °C and 10 g/min, respectively.The model accounts for the distinction between broken and intact oil-bearing cells and describes the extraction kinetics similar to the shrinking core models: it allowed satisfactory fitting of the experimental data and permitted to calculate the effective diffusivity of the oil in the seed, which resulted equal to 3 × 10⁻¹¹ m²/s. The reliability of the model is demonstrated by the fact that the value of the effective diffusivity, resulting from model optimization procedures, is similar for the various experimental tests.     

Supercritical Fluid Extraction Using CO2: Main Applications and Future Perspectives

The main objective of this review is to approach and highlight the main applications of Supercritical Fluid Extraction (SFE) through the search in scientific papers and patents. The principles of the technique and the identification of the main works developed in different areas, such as food science, pharmaceuticals, chemical residues, biofuel, and polymers are presented. Additionally, it presents the new and innovative combined methods where SFE has been used, as well as the perspectives of this technology and the profile of countries that own the rights for the use of SFE through patent registration. In this review a compilation of the data extracted from 196 different scientific article and 594 patent documents, from a universe of 2.314 documents was done, showing the improvement of the technique in the last years.     

Supercritical CO2 extraction of Plumula nelumbinis oil: Experiments and modeling

Supercritical CO₂ extraction of Plumula nelumbinis oil was investigated at temperatures of 308–338 K and pressures of 15–45 MPa. The yield of the extracted oil was 0.128 g/g material at optimal conditions, in which gamma-sitosterol, unsaturated fatty acids and gamma-tocopherol had higher relative concentrations as determined by GC–MS. The broken and intact cell (BIC) model, with reduced adjustable parameters, was utilized to simulate the SFE process. The values of average absolute relative deviation (AARD) were in the range 2.34–10.9%, indicating that the improved method had a similar effect to the BIC model when three parameters were adjusted. The parameters obtained during the modeling had clear physical meanings and were used to gain an in-depth understanding of the SFE process theoretically.     

低分压CO2在有机胺水溶液中的溶解度

建立了一套用于测定低分压CO2在有机胺水溶液中溶解度的实验装置。在298、308 K下分别测定了低分压CO2在较低浓度的乙醇胺(MEA)、二乙醇胺(DEA)水溶液中的溶解度。结果表明,在较低的溶解度下,CO2在有机胺水溶液中的平衡分压接近于0;当溶解度增大到一定程度后,平衡分压随其增加而急剧增大,同时,温度的升高和有机胺浓度的增大均能增大CO2的平衡分压。通过实验数据拟合得到的理论模型参数与实验值符合较好。     

CO2捕集的吸收溶解度计算和过程模拟

为了降低CO2吸收法捕集技术的能耗和成本,以目前常用的单乙醇胺(MEA)溶液吸收CO2为例,采用电解质非随机双流体热力学模型(E-NRTL),对溶液中的CO2气体溶解度进行计算,计算过程包含了化学反应平衡和汽液平衡,计算结果和文献数据相吻合。在此基础上,建立了CO2吸收过程模拟程序和包括解吸能耗、气体压缩能耗以及液体输送能耗的过程总体能耗的计算方法,继而通过过程模拟分析了吸收塔和解吸塔压力、溶液浓度和流量等因素对吸收捕集过程的总体能耗的影响,获取了最优的工艺条件,为以后新CO2吸收捕集过程提供能耗分析方法基础。     

CO2在碳酸二甲酯中的溶解度及强化途径

采用恒定容积法测定了283.15—303.15 K CO2在碳酸二甲酯(DMC)中的溶解度。结果表明,溶解度随压力升高而增大,随温度升高而减小。与碳酸丙烯酯(PC)相比,在283.15 K及288.15 K条件下,CO2在DMC中的溶解度比在PC中平均约高50%。并且常温下DMC的吸收性能优于低温下甲醇的吸收性能。因此,DMC是一种性能更为优越的溶剂。加入1.5 g金属-有机骨架化合物(MOF)ZIF-69后,温度为283.15 K及288.15 K时对DMC吸收CO2具有增强作用,而在295.15 K及303.15 K时无影响。这种特性也有利于CO2吸收和解吸循环过程的节能。