超临界CO2萃取海星皂甙

用正交实验法,通过方差分析,建立并优化了超临界CO2/表面活性剂萃取海星皂甙的工艺。在以浓度为0.075 moL/L的二辛酯琥珀酸磺酸钠(AOT)/辛基酚聚氧乙烯醚(TX-10)组成的复合表面活性剂的正丁醇/乙醇/水多元溶液为助溶剂,萃取压力30 MPa,萃取温度333 K,萃取时间2 h,采取两级分离,分离器(1)的温度为328 K,压力15 MPa,分离器(2)的温度为338 K,压力5 MPa的优化工艺条件下,海星皂甙的萃取率为1.33%,萃取物中海星皂甙质量分数为59.01%,溶血指数为19 231。与乙醇〔w(CH3CH2OH)=85%〕萃取相比,超临界CO2萃取海星皂甙的萃取率提高到1.2倍,质量分数提高到2.0倍,溶血指数提高到1.5倍,所萃取的海星皂甙具有显著的细胞毒性,充分体现了超临界CO2萃取的“绿色”特性。     

不同溶液对地下水中甲基叔丁基醚溶解过程影响

采用实验室小型二维砂箱对地下水流动过程中甲基叔丁基醚(MTBE)溶解过程进行模拟实验,主要考察了非离子型表面活性剂聚乙氧基油酸山梨糖醇(Tween80)、阴离子表面活性剂十二烷基苯磺酸钠(SDBS)与助溶剂乙醇对MTBE溶解过程的影响。结果表明,Tween80在其临界胶束浓度(CMC)以上能够对MTBE起到增溶的效果而且在所研究浓度范围存在最佳增溶浓度10g/L;低于临界胶束浓度条件下的SDBS并没有增强MTBE迁移反而会延缓MTBE的溶解;乙醇可以增大MTBE的溶出浓度,而且随着含量提高增溶效果加强。通过比较各种条件下最佳的MTBE累积去除率可以得出,当MTBE去除率达到80%之前,对MTBE溶解增强效果由大到小顺序依次为:非离子型表面活性剂Tween80> 助溶剂乙醇> 水> 阴离子表面活性剂SDBS;而去除率80%以后,增溶效果的顺序则为乙醇> Tween80> 水> SDBS。     

砂生槐总碱水乳剂及微乳剂农药的研制

为了制备砂生槐生物碱乳剂和微乳剂农药，筛选了不同溶剂和助溶剂系统，考察了亲脂性总碱在不同溶剂系统下的增溶作用。在乳剂配置的基础上，通过绘制生物碱原油-混合表面活性剂-水的拟三元相图，筛选出助表面活性剂乙醇，当Km值（助乳化剂和乳化剂的质量比值）为1：1时有较大微乳区形成。所形成的微乳经过测定是O／W型微乳性质稳定，浊点在57℃。通过论文数据可以指导配置不同质量浓度的砂生槐生物碱乳剂和微乳剂农药。     

增加2,4-D在水中溶解性的方法研究

比较六种表面活性剂对2,4-D在水中溶解性的影响,并研究表面活性剂与乙醇共同作用下2,4-D的水溶性效果。结果表明,胆酸钠和乙醇同时存在对2,4-D有明显增溶作用,且10%(v/v)乙醇和10 g/L胆酸钠溶液对2,4-D溶解效果较好,静置2天后,其溶解率仍有93%。乙醇单因素作用下,使2,4-D完全溶解且不析出的最低乙醇浓度为0.05%(v/v),且先配制2,4-D乙醇溶液,后快速混合于水中,可使2,4-D在水中具有良好的水溶性和稳定性。     

一种乙醇柴油的微乳化性能研究

针对乙醇与柴油互溶性差的特点,采用添加表面活性剂脂肪醇聚氧乙烯醚（AEO3）和助溶剂正戊醇的方法,改变乙醇柴油的微乳化性能。并通过实验考察了它们的最佳复配比,通过乙醇、柴油、稳定剂体系的拟三元相图,考察了温度对其稳定性的影响。最后对乙醇柴油的主要物性进行了测定。通过一系列实验得知,醇类可以作为乙醇柴油混合燃料的助溶剂,正戊醇的助溶效果相对较好;随着温度的降低,乙醇柴油的微乳化液会逐渐变浑浊,最终会分离;乙醇、助溶剂和表面活性剂的加入会降低乙醇柴油的闪点;表面活性剂AEO3作为乳化剂,在醇类稳定剂助溶下（例如AEO3：正戊醇=1：4）制成的乙醇柴油微乳液,稳定时间可达二个月以上。     

乙醇提高水/表面活性剂体系对石墨烯剥离效率的研究

本研究采用液相剥离法以水/乙醇/表面活性剂三元体系为介质剥离石墨烯。当混合溶剂中乙醇的体积分数在50%左右时,石墨烯的浓度达到最大值。石墨烯剥离效率的提高归因于乙醇对溶剂表面能的降低,以及表面活性剂与石墨烯之间的疏水作用力。采用透射电子显微镜、原子力显微镜、拉曼光谱及X射线光电子能谱等对石墨烯的形貌及结构进行了表征。结果表明剥离所得的石墨烯大多数为缺陷很少的少层石墨烯。研究将为石墨烯的绿色高效制备提供一些借鉴。     

溶剂气浮法分离甲基异丁基酮模拟废水

采用溶剂气浮法对含弱疏水性、有一定挥发性甲基异丁基酮(MIBK)的模拟废水(0.20%, j)进行了分离研究. 考察了气浮时间、氮气(N2)体积流速、油水相体积比、共溶质及表面活性剂等对MIBK溶剂气浮分离效率的影响,获得了各参数的优化结果. 结果表明,当N2流速为40 mL/min、油水相体积比为1:30、氯化钠浓度为0.50%(w)、乙醇浓度为1.0%(j)时,溶剂气浮法对模拟废水中MIBK的分离效率可以达到25%~30%左右,而表面活性剂对提高溶剂气浮分离效率作用非常有限,仅在-10%~5%范围内.     

以AEC和MES为主的复配型超浓缩 洗衣液研究

以脂肪醇醚羧酸钠(AEC)和脂肪酸甲酯磺酸盐(MES)为主表面活性剂配制超浓缩洗衣液。通过吊环法研究了AEC与AES复配体系不同比例下静态表面张力和临界胶束浓度,通过单因素和正交试验研究了助溶剂、洗涤助剂、抗再沉积剂的种类及用量对去污力的影响。结果表明,n(AEC)∶n(AES)为8∶2时复配体系cmc最小,助溶剂为乙醇,水溶助长剂为尿素,抗再沉积剂为聚乙烯吡咯烷酮,质量分数分别为10%、1%和0.2%时,超浓缩洗衣液流动性和去污力最好。     

基于表面活性剂增溶技术的薯蓣皂苷萃取研究

采用超声波辅助表面活性剂增溶技术进行薯蓣皂苷的萃取,研究了表面活性剂的种类、碳链长度、HLB值、临界胶束浓度(cmc)等对薯蓣皂苷萃取效果的影响。结果表明,主链长度为12,HLB值不小于15,cmc较小的阴离子表面活性剂对薯蓣皂苷的萃取作用大。进一步研究得到浓度为2.58×10-2mol·L-1的十二烷基硫酸钠溶液宜作为薯蓣皂苷的萃取剂,薯蓣皂苷得率为9.51%。     

泡沫分离法提取乙醇水体系中甲基橙

采用泡沫分离法对含甲基橙的乙醇水溶液进行了提取研究. 考察了乙醇体积分数、气体流量、pH、甲基橙浓度和表面活性剂浓度对提取效果的影响,并对泡沫分离乙醇-水体系中提取中药有效成分的可行性进行了探讨. 结果表明,以十六烷基三甲基溴化铵(CTAB)为表面活性剂,在乙醇体积分数25%的乙醇-水体系中,在pH 6.0、气速80 mL/min、甲基橙浓度35 mg/L及CTAB浓度80 mg/L的操作条件下,甲基橙的富集比为14.38,回收率在98.5%以上. 在一定范围内提高表面活性剂浓度或加入稳泡剂以削弱乙醇的消泡作用,从而将泡沫分离技术应用于乙醇-水体系中中药有效成分的提取是可能的.     

超临界二氧化碳-共溶剂体系与聚醋酸乙烯酯相互作用

采用多尺度模拟和实验结合研究了乙醇、丙酮、正庚烷等共溶剂的加入对超临界二氧化碳（CO₂）溶剂体系的影响,通过改善溶剂-溶剂和溶剂-溶质相互作用增强聚醋酸乙烯酯（PVAc）与CO₂的相容性。量子力学从头算结果表明,3种共溶剂中乙醇与CO₂的相互作用最强,丙酮次之,正庚烷最弱。分子动力学模拟也表明在相同共溶剂含量下,乙醇对溶剂体系溶解度参数的改善最为明显,超临界CO₂-乙醇体系与PVAc链的相互作用更强,有助于提高PVAc与溶剂的相容性。这是由于乙醇本身的溶解度参数较大,且与CO₂形成氢键作用,从而大幅增强了其与CO₂的相互作用。浊点压力实验证实了共溶剂的加入增强了超临界CO₂体系与PVAc的相容性,乙醇的加入对PVAc浊点压力的降低最为有效,且随着共溶剂含量的增加,PVAc在溶剂中的溶解能力增强。     

The action mechanism of ethanol in preparation of supported nano-sized Ru catalyst via supercritical fluid deposition

Ru catalysts supported on activated carbon (AC) were prepared by supercritical fluid deposition (SFD) with ethanol added and their catalytic performance in butanone hydrogenation was investigated. The effects of ethanol amount on Ru particle size were systematically studied. As the amount of ethanol increased, Ru mean particle sizes always decreased firstly, then increased. And the minimum mean particle size of Ru was obtained at 10 ml ethanol. The catalysts with smaller Ru mean particle size presented higher catalytic activity. These results demonstrated that the role of ethanol may not be only co-solvent but also anti-solvent and extractant during the preparation of Ru/AC.     

Continuous production of soybean biodiesel with compressed ethanol in a microtube reactor using carbon dioxide as co-solvent

This work investigates the production of fatty acid ethyl esters (FAEE) from the transesterification of soybean oil in supercritical ethanol in a continuous catalyst-free process using carbon dioxide as co-solvent. The experiments were performed in a microtube reactor in the temperature range of 523 K to 598 K, from 10 MPa to 20 MPa, oil to ethanol molar ratio from 1:20 to 1:40, and co-solvent to substrates mass ratio from 0.05:1 to 0.2:1. Results showed that ethyl esters yield obtained increased with increasing addition of carbon dioxide to the system. Considerable reaction yields were achieved at 598 K, 20 MPa, oil to ethanol molar ratio of 1:20 and using a CO₂ to substrate mass ratio of 0.2:1.     

Selective extraction of phosphatidylcholine from lecithin by supercritical carbon dioxide/ethanol mixture

Selective extraction of phosphatidylcholine (PC) from deoiled soybean lecithin using supercritical fluid (SCF) mixtures of carbon dioxide (CO₂) and ethanol was studied at moderate pressures. Temperature was varied between 60 and 80°C at pressures of 17.2 and 20.7 MPa. Ethanol was added as co-solvent to supercritical CO₂ at the levels of 10 and 12.5 wt%. Constant rate of extraction of the individual phospholipids (PL) was observed for 150 min during which the extractions were carried out. Pressure and ethanol fraction had a positive effect on the selective extraction of PC, whereas temperature had a negative effect. Under all the conditions studied, the extracts were mainly composed of PC while the extraction of the other PL was very low. Extraction at 60°C and 20.7 MPa with 10 wt% ethanol/90 wt% CO₂ SCF mixture resulted in 95% selectivity to PC.     

Study on supercritical extraction of lipids and enrichment of DHA from oil-rich microalgae

The present study aims to isolate the lipids from microalgae by supercritical CO₂ (SC-CO₂) extraction followed by a further enrichment of crude lipids to produce high-purity docosahexenoic acid (DHA) by an urea complexation method. Our systematic approach indicates the optimum conditions of supercritical CO₂ extraction were obtained as follows: 35 MPa, 40 °C, ethanol (95%, v/v) as the co-solvent, and the mass ratio of material to co-solvent 1:1. Under these conditions, 33.9% of lipid yield and 27.5% of DHA content were achieved. Despite the relatively low lipid yield, supercritical CO₂ extraction has exhibited many advantages over the Soxhlet extraction for the DHA enrichment such as high DHA purity and superb product quality. Furthermore, urea complexation method on DHA enrichment considerably increased the DHA purity from 29.7% to 60.4% with an enrichment ratio of 60.6%, under the optimum complexation conditions of urea/fatty acid 2:1, complexation time 8 h, and the complexation temperature of −10 °C.     

Continuous catalyst-free production of fatty acid ethyl esters from soybean oil in microtube reactor using supercritical carbon dioxide as co-solvent

This work reports the transesterification of soybean oil in supercritical ethanol in a continuous catalyst-free process in microtube reactor using carbon dioxide as co-solvent. For this purpose it was employed two microtube reactors with different internal diameter, 0.775 and 0.571 mm. The experiments were performed in the temperature range of 523-598 K, pressure of 10 MPa and 20 MPa, oil to ethanol molar ratio of 1:20 and 1:40, and co-solvent to substrates mass ratio from 0.05:1 to 0.2:1. Results demonstrated that temperature, pressure and co-solvent to substrate mass ratio had a positive effect on fatty acid ethyl esters (FAEE) production, with appreciable yields achieved at 598 K, 20 MPa, oil to ethanol molar ratio of 1:20, using a CO₂ to substrate mass ratio of 0.2:1. The micro-reactor with the smallest inner diameter led to slightly higher FAEE yields at the specified reactions conditions compared to the micro-reactor with greater internal diameter. A semi-empirical kinetic model was proposed in attempt to represent the experimental data with satisfactory fitting results found.     

Study on Oleuropein Extraction from Olive Tree (Olea europaea) Leaves by means of SFE: Comparison of Water and Ethanol as Co-Solvent

The present study focuses on developing methods for olive leaf extraction and deals with obtaining extract, rich in oleuropein, which is the most abundant phenolic compound in olive leaves. Supercritical fluid extraction (SFE) was applied to the dried and ground olive leaves by using CO₂ as supercritical (SC) fluid in the presence of water and ethanol as co-solvent. The influences of operating parameters by means of co-solvent content (0-1 mL/min), temperature (50 and 100°C) and pressure (100-300 bar) on both extract and oleuropein yields were investigated. Quantitative analysis was performed by using a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) technique. The experimental results obtained by using SC-CO₂ alone were not satisfactory, and it was seen that addition of a polar modifier is necessary in order to improve yield and selectivity of the process. It was observed that CO₂ modified by water and ethanol showed nearly the same extract performance, where CO₂ modified by water is better for high oleuropein yield.     

Surface properties in binary mixtures of aerosol OT and nonionic surfactants

The surface tensions of the mixed systems consisting of sodium di-2-ethylhexyl sulfosuccinate (Aerosol OT) and homogeneous polyoxyethylene glycol-n-dodecyl ether (nED; n=5 to 8) were measured in the absence and presence of sodium chloride (NaCl) by a modified Wilhelmy plate method. In the case of the system containing nED and Aerosol OT, the nED concentrations were fixed at various amounts, and all the surface tension curves approached 32 or 33 mN/m as the concentration of Aerosol OT approached 1 × 10⁻³ mol/l. On the other hand, when the Aerosol OT concentration was fixed at 1 × 10⁻³ mol/l, the surface tension curves for the mixed system showed a flat portion in the range where mixed micelle in the solution and the two dimensional ones on the water surface were formed. Further, molecular interaction parameter B was calculated by the Rosen extension of the regular solution treatment of Rubingh. The average values of B in the nED-AOT systems increased as the value of n increased. The values of B increased with increasing activity of AOT. In the case of the system containing 6ED, AOT and NaCl, the surface tension curves showed inflection points shifted to higher concentrations of AOT as the concentration of nED increased.     

Continuous production of soybean biodiesel with compressed ethanol in a microtube reactor

This work investigates the production of fatty acid ethyl esters (FAEEs) from the transesterification of soybean oil in supercritical ethanol in a continuous catalyst-free process. Experiments were performed in a microtube reactor in the temperature range of 523 K to 598 K, from 10 MPa to 20 MPa, varying the oil to ethanol molar ratio from 1:10 to 1:40, and evaluating the effects of addition of carbon dioxide as co-solvent. Results showed that ethyl esters yield obtained in the microtube reactor (inner diameter 0.76 mm) were higher than those obtained in a tubular reactor (inner diameter 3.2 mm) possibly due to improved mass-transfer conditions attained inside the microtube reactor. Non-negligible reaction yields (70 wt.%) were achieved along with low total decomposition of fatty acids (< 5.0 wt.%). It is shown that the use of carbon dioxide as co-solvent in the proposed microtube reactor did not significantly affect the ethyl esters yield within the experimental variable ranges investigated.