Combination of supercritical fluid extraction with dispersive liquid-liquid microextraction for extraction of organophosphorus pesticides from soil and marine sediment samples

Supercritical fluid extraction (SFE) coupled with dispersive liquid-liquid microextraction (DLLME) and followed by gas chromatography-flame ionization detection (GC-FID) was applied for extraction and determination of ultra-trace amounts of seven organophosphorus pesticides (OPPs) (o,o,o-triethyl phosphorothioate, thionazin, sulfotepp, disulfoton, methyl parathion, parathion, and famphur) in soil and marine sediment samples. Supercritical CO₂ at 150 bar, 60 °C, 10 min static and 30 min dynamic extraction times was used to extract the pesticides. The extracts were collected in 1.0 mL of acetonitrile. Seventeen μL of carbon tetrachloride was dissolved in the collecting solvent and the mixture was then injected rapidly into 5.0 mL of aqueous solution. About (5.0 ± 0.2 μL) of sediment phase was collected after centrifuging and finally 2.0 μL of it was injected into gas chromatography (GC) injection port for analyses. The extraction recoveries for the target analytes were in the range of 44.4% and 95.4% and relative standard deviation (RSD%) for four-replicate measurements was below 7.5%. The limit detections of the method for determining the pesticides were in the range of 0.001-0.009 mg kg⁻¹. The method was successfully applied for analysis of OPPs in real soil and marine sediment samples and satisfactory results were obtained.     

Supercritical fluid extraction combined with dispersive liquid-liquid microextraction as a sensitive and efficient sample preparation method for determination of organic compounds in solid samples

The supercritical fluid extraction (SFE) followed by the dispersive liquid-liquid microextraction (DLLME) has been developed for extraction and determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. PAHs were employed as model compounds to assess the extraction procedure and were determined by gas chromatography-flame ionization detection (GC-FID). SFE of PAHs was performed at 313 K and 253.2 bar, at static and dynamic times 10 and 30 min, respectively. The extracted PAHs were collected in 1 mL of acetonitrile. Subsequently, 16 μL of chlorobenzene (as extraction solvent) was added to collecting solvent (1.0 mL of acetonitrile). Then, the resulted mixture was injected into 5.0 mL of aqueous solution, rapidly. After centrifugation, the PAHs in the sedimented phase were analyzed by GC-FID. Effects of significant parameters on the extraction in SFE and DLLME methods were investigated. Under the optimum conditions, the calibration plots were linear in the range of 0.4-41.6 mg kg⁻¹ and the limits of detection (LODs) were 0.2 mg kg⁻¹ for all of the analytes. Analysis of PAHs in different solid samples showed that the improved technique has great potential for PAHs analysis in marine sediments. SFE-DLLME leads to high preconcentration factor, easy use of DLLME in solid samples and solving the main problem of SFE that is the extra step (vaporization of large volume of toxic organic solvent) after extraction needed prior to final analysis.     

桑葚果渣花色苷的低共熔溶剂提取与分离

以桑葚果渣为原料,在低共熔溶剂(DESs)中,经DESs提取与大孔树脂分离两步,回收了果渣中花色苷.测试了不同类型DESs与提取方法对花色苷提取率的影响,通过不同型号大孔树脂作为吸附载体对花色苷进行回收以脱除DESs.采用HPLC、HPLC-MS对花色苷进行定量与定性分析.结果表明,DESs中草酸-氯化胆碱〔n(草酸)...     

低共熔溶剂用于萃取分离的研究进展

作为一种新型的绿色溶剂,低共熔溶剂（DES）拥有与离子液体媲美的优良特性,如挥发性小、可设计性等,且具有成本低廉和制备简单的优势,使得DES正逐步替代传统有机溶剂,在萃取分离应用方面得到广泛的关注。本文综述了近年来国内外有关DES在萃取分离方面的研究报道,阐述了DES直接用于液液萃取、在线生成DES的缔合萃取和通过DES分解完成萃取的应用,并分析比较了各过程的特点和存在的问题;介绍了DES在不同萃取体系中的稳定性和DES的回收方法;总结了DES萃取分离体系的理论发展和萃取机理的研究进展;展望了DES用于萃取分离的工业化前景,指出了目前面临的DES理论、萃取机理、循环稳定性等方面的挑战,分析了进一步的研究趋势。     

苯酚型低共熔溶剂中硫酸钛作为催化剂高效氧化脱硫

低共熔溶剂广泛应用于氧化脱硫过程,开发新型的低共熔溶剂并进一步提升脱硫效果具有重要的意义。 以氯化胆碱为氢键受体,苯酚为氢键供体合成了ChCl/2Ph型低共熔溶剂。通过FT-IR和¹H NMR证实了苯酚和氯化胆碱之间存在氢键作用。以苯酚型低共熔溶剂为萃取剂,双氧水为氧化剂,硫酸钛为催化剂氧化脱除模拟油中的二苯并噻吩。考察了反应温度、V(ChCl/2Ph)/V(Oil)、n(H₂O₂)/n(S)、催化剂用量以及硫化物类型对脱硫率影响。实验表明最佳反应条件如下：模拟油量为5 ml,V(ChCl/2Ph)/V(Oil)=2∶10, n(H₂O₂)/n(S)=6,催化剂用量为0.01 g,反应温度为40℃,反应时间180 min。在此条件下脱硫率可以达到98.2%。求得体系的表观活化能为41.9 kJ/mol。含有催化剂的低共熔溶剂相可以重复使用5次且活性没有明显降低。机理研究表明形成钛的过氧化物和Br?nsted酸性是具有较高脱硫活性的关键。     

Bifunctional imidazole-PTSA deep eutectic solvent for synthesizing long-chain ester IBIBE in reactive extraction

The traditional production of long-chain organic esters like isobutyl isobutyrate (BIBE) suffers from severe problems due to the homogenous catalyst in process and complex system thermodynamics. In this work, an innovative bifunctional deep eutectic solvent (DES) is introduced, playing as both reaction catalyst and extraction solvent, to intensify the esterification process. The DES was formed by imidazole (Im) and p-toluenesulfonic acid (PTSA), which was for the first time found acid–base tunable, represented by weak basic DES [3Im:PTSA] and strong acidic DES [Im:2PTSA]. The formation mechanisms of [3Im:PTSA] and [Im:2PTSA] were illustrated by Fourier-transform infrared spectroscopy (FTIR) and COnductor-like Screening MOdel for Real Solvent (COSMO-RS) combined with the Im-PTSA phase diagram. The dual functions of the acidic [Im:2PTSA] in reactive extraction were evaluated by σ-potential analysis and esterification experiments. The high conversion, easy product separation, and good solvent reusability confirm the excellent catalytic and solvent effect of [Im:2PTSA]. © 2018 American Institute of Chemical Engineers AIChE J, 65: 675–683, 2019     

A sensitive and selective deep eutectic solvent-based ultrasound-assisted liquid phase microextraction procedure for separation-preconcentration and determination of copper in olive oil and water samples

ABSTRACT

A green and simple deep eutectic solvent-based ultrasound-assisted liquid phase microextraction method has been developed for the preconcentration of copper as 2-(5-bromo-2-pyridylazo)-5-(diethylamino) phenol chelates. The effects of pH, ligand concentration, DES volume, sample volume, and tetrahydrofuran volume were investigated. Analytical performance parameters like limit of detection, limit of quantification, preconcentration factor, and relative standard deviation were determined as 6.6 μg L^?1, 21.8 μg L^?1, 15, and <5%, respectively. Validation of the developed method was checked by the analysis of certificated reference materials. The procedure was successfully applied to determination of copper in olive oil and water samples.     

深度共熔溶剂预处理木质纤维素生物质研究进展

木质纤维素生物质转化为生物燃料或化工产品一般需经历预处理、酶解及发酵过程,因其复杂的化学结构,在酶解前通常进行预处理以破坏其致密结构,提高酶与纤维素的可及性。深度共熔溶剂（DES）是一类新型的“绿色”溶剂,具有制备简单、价格低廉、性质可调、可生物降解、可循环使用等优势,可有效去除木质素组分,同时保留大部分纤维素,在生物质预处理方面具有巨大的潜力。本文介绍了DES的构成、分类及理化性质,总结了DES预处理对生物质组分的影响,并对预处理效果的影响因素如底物和DES的类型、溶剂黏度、温度、生物载量、微波及超声波辅助工艺和两阶段处理工艺等方面进行分析,探讨了DES和生物的相容性,最后针对DES存在的问题及缺点,提出了理性设计和大规模利用DES的机遇与挑战,本文可为实现生物质的低成本预处理和高价值利用提供新的思路。     

疏水性低共熔溶剂氢键交互作用调控及萃取铜性能

制备了以薄荷醇为氢键受体,不同碳链长度的羧酸为氢键供体的薄荷醇-羧酸类疏水性低共熔溶剂。探索了低共熔溶剂体系的密度、黏度理化特性随温度变化的规律,利用超额摩尔性质与格伦伯格-尼桑相互作用力公式计算了过量摩尔体积、黏度偏差与相互作用力参数,分析了低共熔溶剂组分间的相互作用。通过傅里叶红外光谱表征,确定了低共熔溶剂组分间的氢键作用。以该类低共熔溶剂作萃取剂,考察了pH、组分间氢键交互作用力（氢键供体碳链长度、低共熔溶剂受供体摩尔比）对提取铜性能的影响。结果表明,薄荷醇-羧酸类疏水性低共熔溶剂中氢键交互作用更强的体系,由于羧基中氢的解离更容易实现,对铜的萃取效率更高。此外,通过对薄荷醇-羧酸类疏水性低共熔溶剂体系结构性质与组分间氢键作用的关系对铜的萃取机理进行了探讨,为揭示疏水性低共熔溶剂的构效关系与高性能低共熔溶剂的设计优化提供理论基础。     

Association extraction for vitamin E recovery from deodorizer distillate by in situ formation of deep eutectic solvent

An innovative intensified vitamin E (VE) recovery process from the methylated oil deodorizer distillates (MODDs) was proposed, where VE was in situ transferred into a deep eutectic solvent (DES) with an organic salt. To design the process, the chlorine based quaternary ammonium salts were primarily investigated, and [N_4,4,4,4]Cl was selected as an association solvent which can efficiently form DES with α‐tocopherol of the representative compound of VE. Based on the determined phase diagram of the DES freezing points, four phase regions were classified, and the effect of the [N_4,4,4,4]Cl/tocopherol ratio and temperature on the extraction performance and phase transformation was figured out. Moreover, an intensified association extraction process via in situ forming DES of α‐tocopherol with [N_4,4,4,4]Cl was designed and validated by experiments. VE products were finally obtained from both model MODD (purity of 99.63%) and practical MODDs (purity of >79.18%), which verifies the excellent extraction efficiency for the proposed recovery method. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2212–2220, 2017     

新型银基低共熔溶剂制备及其在1-己烯/正己烷分离中的应用

相同碳数的正构烯烃与正构烷烃因其结构相似,使其相对挥发度较小、分离难度较大。低共熔溶剂（DES）作为一种可设计的绿色分离介质被广泛应用于该类混合物的分离中,此外过渡金属与烯烃双键之间的化学络合作用是促进正构烯烃/烷烃分离的一个重要方法。鉴于此,开发了新型银基低共熔溶剂（Ag-DES）,并将其应用于1-己烯/正己烷的分离,系统探究了原料中烯烃浓度、银离子与烯烃摩尔比、分离温度等对1-己烯分离性能的影响,结果显示Ag-DES具有良好的1-己烯/正己烷分离选择性,选择性在3.5~18之间,并具有出色的循环稳定性。进一步通过FT-Raman表征和量化计算揭示了Ag-DES与烯烃之间的化学络合作用和较强氢键作用是实现其与烷烃分离的本质原因,表明应用Ag-DES的反应萃取分离强化方法可实现从F-T合成油中绿色高效分离C₆α-烯烃。     

基于COSMO-SAC模型的离子液体萃取剂的选择

COSMO-SAC模型是计算无限稀释活度因子的一种有效方法,只需知道分子结构,即可进行有机物或离子液体的无限稀释活度因子计算。COSMO-SAC模型中最耗时的计算步骤是产生σ-图谱(σ-profile)的量子化学计算。利用Materials Studio软件中的DMol3模块,建立了包含32种离子液体阴离子和191种离子液体阳离子的σ-图谱数据库。利用σ-图谱数据库和COSMO-SAC模型,针对离子液体液液萃取过程,提出了离子液体萃取剂的计算机辅助分子设计方法。以乙醇-乙酸乙酯体系为研究对象,选择了适宜的离子液体萃取剂,采用乙醇-乙酸乙酯-离子液体三元体系的液液平衡文献数据进行了验证。     

基于尿素/氯化胆碱低共熔溶剂体系纳米流体制备及其热物性研究

随着电子工业的快速发展,传统换热工质由于其较低的热导率已无法满足越来越高的换热需求。另一方面,传统的换热工质受限其相对较窄的液程范围而无法使用于复杂的温况或特殊的工作条件。低共熔溶剂（DESs）具有与离子液体相似的低饱和蒸气压、高沸点及强稳定性等优势,在传热领域具有巨大的潜力。制备了以尿素/氯化胆碱低共熔溶剂体系为基液,石墨烯、Al₂O₃、TiO₂三种纳米粒子填充的纳米流体,研究了黏度、热导率等热物性与纳米粒子和基液组成之间的关系,并系统地研究了纳米粒子结构对其稳定性的影响。实验结果表明,纳米粒子的填充会在一定程度上增加基液的黏度,其中石墨烯填充的纳米流体的黏度增加最大。此外,石墨烯能显著提高DESs的导热性能,其中6%（质量）石墨烯纳米流体热导率相比基液可增加29.0%。     

低共熔溶剂与偶联剂协同改性白炭黑对胎面胶性能的影响

研究了硅烷偶联剂(TESPT)与低共熔溶剂(DES)协同改性白炭黑对作为胎面胶的天然橡胶复合材料性能的影响.用傅里叶变换红外光谱分析了 TESPT和DES与白炭黑之间的相互作用,用橡胶加工分析仪和扫描电镜分析了白炭黑之间的相互作用,并测试了复合材料的硫化特性、力学性能和耐磨性,通过动态力学分析仪考察了其滚动阻力和抗湿滑...     

Extraction of ferulic acid from oil palm pressed fiber by a choline chloride based deep eutectic solvent

Results on the extraction of ferulic acid from palm pressed fiber using deep eutectic solvent (DES) of choline chloride-acetic acid (ChCl-AA) and choline chloride-citric acid (ChCl-CA) are reported. Acetic acid was found to be a better hydrogen bond donor to choline chloride than citric acid for the extraction of ferulic acid. Influence of water content in both DES was investigated whereby ChCl-AA and ChCl-CA experienced a drop in viscosity from 9.678 to 1.429 and 22.658 ± 1.655 mm²/s, respectively as the water content in the DES increased from 0 to 50 wt%. The drop in viscosity contributed to higher extraction efficiency in which 41,155 ± 940 mg/kg ferulic acid was obtained after 6 h reflux when ChCl-AA with 30 wt% water was used for the extraction compared to 30,940 ± 621 mg/kg when neat ChCl-AA was used. Further increase in water content in the DES however, did not lead to higher extraction efficiency. Although viscosity of the DES could be improved with the addition of water, there is a threshold where the DES could tolerate the presence of water without changing its solvent behavior. Surface response model revealed that interaction between heating duration and water content in DES, as well as second order effect of both heating duration and water content in DES played important roles in the extraction of ferulic acid from oil palm pressed fiber. The optimum condition for extraction of ferulic acid from palm pressed fiber was heating for 6 h with DES containing 30 wt% water.     

甲酸/盐酸胍DES温和高效分离毛竹木质素

以毛竹为原料,采用甲酸/盐酸胍酸性低共熔溶剂（DES）温和高效分离木质素,并对其结构、热稳定性和抗氧化性进行了表征。结果表明,甲酸/盐酸胍（摩尔比为4:1）DES实现了温和短时条件下（100 ℃,2 h）高效分离木质素（得率为59.31%）,当进一步升温至120 ℃时,得率可达73.98%,其原因是该酸性体系中氢质子使木质素中大量的β-O-4、β-β、β-5连接键断裂,促使木质素大分子解聚成小分子而溶出。分离的木质素纯度高于96.6%,分子量低（Mw=1040~2040 g/mol）,多分散系数小于1.5,结构均一,热稳定性好。同时,该木质素抗氧化活性强（IC50=0.016~0.045 mg/ml）,优于商业抗氧化剂丁基羟基茴香醚（IC50=0.056 mg/ml）。     

Investigation of the effects of ternary deep eutectic solvent composition on pretreatment of sorghum stover

Biomass-derived deep eutectic solvents (DESs) have been introduced as promising pretreatment and fractionation solvents because of their mild processing conditions, easy synthesis, and green solvent components from biomass. In recent DES studies, solvent-based third constituents like water, ethanol, and others improve the processibility of typical binary DESs. However, the impacts of these components are not well understood. Here, two solvent-based constituents, including water and ethylene glycol, were applied to 3,4-dihydroxybenzoic acid (DHBA)-based DES system for improving the conversion efficiency of cellulose-rich fraction and the properties of lignin fraction. Chemical composition, enzymatic digestibility, degree of polymerization of cellulose and physicochemical properties of lignin were used to evaluate the impact of each third constituent on biomass processing. Ternary ChCl-DHBA DESs exhibited better performances in delignification, fermentable sugar production, and preservation of β-O-4 ether linkage in lignin compared with binary ChCl-DHBA DES.