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2-萘酚与苯甲酸在含夹带剂的超临界流体中溶解度的研究 总被引:7,自引:0,他引:7
在自建的超临界流体溶解度实验装置中,测定了固体溶质2—萘酚、苯甲酸在超临界CO2中的溶解度,实验对该类物质的超临界萃取提供了基础数据。对数据的分析讨论表明,随着压力的升高,物质的溶解度增高;随着温度的升高,溶解度的变化比较复杂,在低于特定压力(转变压力)时,温度升高,溶解度增高;在高于特定压力时,温度升高,溶解度降低;夹带剂可以大大提高固体溶质的溶解度,不同的夹带剂,所起作用大小不同;夹带剂的极性、氢键作用对溶解度的提高起着很重要的作用。 相似文献
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以70%的岩白菜素为原料,采用超临界CO2萃取重结晶岩白菜素,考察了甲醇、乙醇、丙酮和乙酸乙酯4种夹带剂对超临界CO2萃取重结晶岩白菜素的结晶率、纯度、形貌和IR图谱等的作用规律.结果表明,在萃取结晶压力为15 MPa、萃取温度为55℃、萃取时间为50 min、CO2流量为15 L·min-1的条件下,乙醇作夹带剂时重结晶纯化岩白菜素的综合效果最好,结晶率达60%以上、重结晶纯度达92%以上,且能保持晶体的优良晶型和结晶品质,综合评价后优选乙醇为夹带剂. 相似文献
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测定了2-羟基苯甲酸在308.15K和328.15K,10.0-25.0MPa条件下,在含和不含夹带剂的超临界CO2中的溶解度数据;分析了夹带剂对超临界流体中固体溶质溶解度的作用机理,得到选择夹带剂的一般原则。 相似文献
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超临界CO2流体萃取大黄游离蒽醌的研究 总被引:10,自引:0,他引:10
研究了带夹带剂的超临界流体萃取大黄中的五种有效蒽醌类物质(大黄酚、大黄素、芦荟大黄素、大黄酸和大黄素甲醚)的工艺,考察了萃取条件(温度和压力)、CO2流量、萃取时间、夹带剂种类等对大黄游离蒽醌萃取率的影响.通过正交实验对萃取釜条件(萃取压力、温度和夹带剂用量)进行了优化;采用液相色谱对萃取产物进行了分析.结果表明,分离釜的温度和压力、CO2流量等对萃取效率影响较小;最佳工艺条件为静萃取时间为60 min、动萃取时间为30 min、以乙醇作夹带剂、乙醇用量300 mL·(100g大黄)-1、萃取温度45℃、萃取压力45 MPa.在此条件下大黄游离蒽醌的萃取量达1.15%. 相似文献
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在200 mL高压萃取釜内,对含夹带剂的超临界CO2萃取回收SBA-15中有机模板剂P123(EO20PO70EO20)的最佳工艺条件进行了研究,考察了夹带剂种类、萃取温度、萃取压力、夹带剂流量对回收率的影响,确定最佳萃取工艺条件为:甲醇作夹带剂,温度45℃,压力27 MPa,夹带剂流量4 mL/min,萃取时间1.5 h,在此条件下P123回收率可达73.7%. 对不同方法脱除P123后的SBA-15进行了表征,结果表明,含甲醇夹带剂的超临界CO2萃取法是一种高效环保的方法,且得到的SBA-15保留了很好的骨架有序性,不会造成骨架硅羟基脱除,克服了高温焙烧脱除模板剂造成的孔道收缩问题. 相似文献
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Analysis of cosolvent effect on supercritical carbon dioxide extraction for α-pinene and 1,8-cineole
Yusuke Shimoyama Hiroki Tokumoto Takumi Matsuno Yoshio Iwai 《Chemical Engineering Research and Design》2010,88(12):1563-1568
The solubilities of α-pinene and 1,8-cineole in supercritical carbon dioxide with and without cosolvent were measured by using a circulation type apparatus coupled with an on-line Fourier transform infrared (FT-IR) spectroscope at 323 K and 8.0 MPa. The cosolvents interested in this work were ethanol, water, acetone and hexane. The solubilities were measured under vapor–liquid two phases. The effects of cosolvents on the solubilities and selectivities of α-pinene and 1,8-cineole in supercritical CO2 were investigated. The selectivities at feed concentration of cosolvent of 0.056 mol L−1 were increased 1.23 times by ethanol and decreased 0.82 times by hexane. Peng–Robinson equation of state with a quadratic mixing rule was used for correlations of the solubilities for α-pinene and 1,8-cineole in supercritical CO2 with and without cosolvent. The correlated results reproduce the experimental data of cosolvent effects on the solubilities and selectivities of α-pinene and 1,8-cineole in supercritical CO2. 相似文献
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Min Jeong Noh Tae Gyun Kim In Kwon Hong Ki-Pung Yoo 《Korean Journal of Chemical Engineering》1995,12(1):48-55
A new transparent microscale circulation-type high pressure equilibrium cell with on-line sampling was devised. With this
apparatus, experimental solubility of molecularly complex species such as steroids (cholesterol, stigmasterol and ergosterol)
and fatty acids (palmitic acid and stearic acid) in supercritical carbon dioxide(sc-C02) were measured. Also, to find an appropriate substance for enhancing both the polarity and the solubility power of the SC-CO2 solvent, we arbitrarily selected three polar substances such as acetone, methanol and water and the effect of these cosolvents
on the solubility of solutes in SC-CO2 are examined. The supercritical phase equilibrium data of solute-cosolvent-sc-CO2 systems were quantitatively correlated using a new equation of state based on the lattice fluid theory incorporated with
the concept of multibody interaction. We found that the addition of tracer amount of acetone or methanol to SC-CO2 enhances the solubility of all solutes about thirty to sixty times when compared with the case of pure sc-CO2 However, for the case of cosolvent water, no further enhancement of the solubility of solutes was realized. Also, the versatile
fittability of the equation of state proposed in this work was demonstrated with the newly measured ternary supercritical
equilibrium data. 相似文献
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Julin García Francisco Rodríguez Juan A Revenga 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2000,75(3):245-251
A Response Surface Methodology approach to correlate the solubility data of solids in supercritical fluids directly to the pressure and temperature is described. Published data for 2,6‐dimethylnaphthalene, 2,3‐dimethylnaphthalene, phenanthrene and benzoic acid in both supercritical carbon dioxide and supercritical ethylene were correlated by means of quadratic models, with R2 statistics greater than 0.99 at more than a 99.9% confidence level. With the developed quadratic models, the solubility for the above‐mentioned solids in both supercritical fluids was predicted with average absolute percentage errors less than 5%. So, this approach to estimate solubility provides a possible guide for saving experimental effort and then giving simple models that could be used for industrial design purposes. © 2000 Society of Chemical Industry 相似文献
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Poongunran Muthukumaran Ram B. Gupta Hwan-Do Sung Jae-Jin Shim Hyo-Kwang Bae 《Korean Journal of Chemical Engineering》1999,16(1):111-117
The use of supercritical carbon dioxide is emerging as a potential method for achieving pollution-free dyeing. An important
factor in supercritical fluid dyeing is the solubility of the dye in supercritical carbon dioxide. Our measurements show that
the solubility of C. I. Disperse Red-60 dye in supercritical carbon dioxide is significantly enhanced upon addition of polar
csolvents : ethanol and acetone. The solubility enhancement is attributed to the formation of hydrogen bonds between cosolvent
and dye molecules. Observed solubility behavior is correlated using dilute-solution theory with lattice-fluid-hydrogen-bonding
model. Needed physical and hydrogen-bonding molecular parameters are estimated using the experimental data. 相似文献
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Solubility of the silver nitrate in the supercritical carbon dioxide containing ethanol and ethylene glycol as double cosolvents was measured under certain pressure and temperature range(10–25 MPa, 323.15–333.15 K). The impact of the pressure and temperature on the solubility was also investigated. Based on the experiment data,a correlation model concerning solid's solubility in supercritical fluids was established by combining the solubility parameter with the thermodynamic equation when a binary interaction parameter and a mixed solvent solubility parameter were defined. Experiments show the solubility of AgNO_3 increases with the pressure at a certain temperature. However, the influence of temperature is related to a pressure defined as the turnover pressure(12.3 MPa). When the pressure is higher(or lower) than this turnover pressure, silver nitrate's solubility shows increasing(or decreasing) trend as the temperature rises. Satisfactory accuracy of our presented model was revealed by comparing experimental data with calculated results. 相似文献
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Using a specially created experimental setup, the crossover character of a change in solubility is determined, and the approximate pressure at the upper crossover point is found (≈19 MPa). The modification of carbon dioxide with chloroform is shown to increase its solubility by 2–2.5 times on average within the above range of conditions. The supercritical CO2 fluid extraction (SCFE) process is studied as it applies to the regeneration of LD-265 alumopalladium hydrogenation catalyst. Dimethylsulfoxide and ethanol are selected as cosolvents (modifiers). Maximum regeneration efficiency is established at a 5.5–6.5 wt % concentration of cosolvents, and dimethylsulfoxide proves to be a more efficient cosolvent than ethanol. The diene and bromine numbers and styrene and methylcyclopentadiene conversions obtained on catalysts regenerated via SCFE satisfy the requirements for catalytic systems used in the selective hydrogenation of dienes in a benzene–toluene–xylene fraction. 相似文献
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《Chemical Engineering Research and Design》2014,92(12):2970-2976
Equation of state based on hole theory with molecular surface charge density was developed for the modeling of drug solubility in supercritical carbon dioxide. In the hole theory, the density change of supercritical carbon dioxide can be represented by the number of holes in the system. The molecular interaction energy parameter was estimated using the interactions of segments on the molecular surface given by a quantum calculation using conductor-like screening model. The only one parameter, coordination number around a molecule was fitted to the experimental data of the drug solubility in supercritical carbon dioxide. The solubilities of the eighteen drugs in supercritical carbon dioxide were modeled by the equation of state with the molecular surface charge density. The effect of the molecular pair for the coordination number on the correlated results was investigated. It is found that the results using the fitted parameter of the solute–solute pair coordination number result in the modeling performance better than those of carbon dioxide–solute coordination number. The results of the modeling of drug solubility in supercritical carbon dioxide are compared with the experimental data. The average absolute relative deviation between the experimental and calculated results of the solubility for the drug composed of C, H and O atoms acetylsalicylic acid, benzoic acid, ferulic acid, (S)-naproxen, p-benzoquinone, propyl gallate, salicylic acid and vanillic acid is 0.38 smaller than those for compounds including N, F, I and S atoms, amical-48, benzocaine, caffeine, carbamazepine, (±)-flurbiprofen, methimazole, phenazopyridine, theobromine, theophylline and uracil, 0.59. 相似文献
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Ethanol was used as a cosolvent to enhance the solubility of disperse dyestuffs in supercritical fluids. In the presence of ethanol, from (1 to 5) mol%, the gas–solid equilibrium data of the Disperse Red 82 and modified Disperse Yellow 119 in supercritical carbon dioxide or nitrous oxide have been measured at temperatures from (353.2 to 393.2) K and pressures from (15.0 to 30.0) MPa. The experimental results show that the solubility increases substantially, up to (9 to 25)-fold, by adding 5 mol% of ethanol to the supercritical fluids. In the presence of cosolvent ethanol, the solubility enhancements in nitrous oxide system are much greater than that in carbon dioxide system for modified Disperse Yellow 119 at the same temperature and pressure. The solubility data were correlated with the Chrastil and the Méndez-Santiago and Teja models. The Méndez-Santiago and Teja model yields slightly better results than Chrastil model. 相似文献