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1.
作为新型绿色溶剂,离子液体在油脂工业中有着广泛的应用潜力。离子液体对于许多有机小分子、生物分子以及金属离子等均具有良好的溶解性。由于离子液体具有不挥发、流动性范围广、可设计性强等优点,其能够替代部分传统有机溶剂应用于脂质的分离与富集。从离子液体的性质、在提取微藻油脂中的应用、在分离与富集油脂中各组分的应用、在富集油脂中风险物质的应用4个方面对离子液体在脂质分离与富集中的应用研究进展进行了综述,最后对离子液体在脂质分离与富集方面的研究前景进行了展望。  相似文献   

2.
离子液体合成及其应用研究   总被引:2,自引:1,他引:2  
离子液体具有很多独特的物理、化学性质,正引起人们越来越多的重视,被认为是一类可以取代传统有机溶剂对环境友好的新型绿色溶剂,在很多领域中有着诱人的应用前景。文中对离子液体的性质、合成方法以及在萃取分离、有机化学、电化学、催化反应、食品工业中的应用进行了阐述。  相似文献   

3.
离子液体作为一类极具有发展潜力的绿色溶剂,其用于酶催化反应介质有着传统有机溶剂和功能性离子液体无法超越的优势。综合对国内外近十几年公开发表的有关离子液体中酶法催化合成糖酯的文献,从常见离子液体分类,离子液体对酶活性、稳定性和选择性的影响,以及糖酯酶法催化合成的方法及研究现状进行了归纳与总结,同时指出了今后在离子液体中糖酯酶法催化合成领域值得研究的重要内容。   相似文献   

4.
This work aims to study the effect of pretreatment of wool fabrics with two imidazolium-based ionic liquids to impart durable antimicrobial properties. The used ionic liquids, cationic in nature, were ionically bonded to the anionic sites along the keratin macromolecules. These anionic sites have been enriched via treatment with the presynthesized anionic agent (AA) (sodium 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate). The effect of the treatment temperature of wool fabric with the AA, liquor ratio as well as the pH on the exhaustion percentage was studied. Antibacterial activity of the treated wool fabric towards Gram –ve bacteria (Escherichia coli), and fastness to washing were examined. The chemical structure of the synthesized AA was elucidated using liquid chromatography mass spectrometry.  相似文献   

5.
Enantioselective esterification of (±)-menthol was studied using Candida rugosa lipase (CRL) in ionic liquids (1-butyl-3-methyl-imidazolium hexafluorophosphate ([BMIM][PF6]) and 1-butyl-3-methyl-imidazolium tetraflouroborate) and organic solvents of different hydrophobicities. Propionic anhydride was employed as an acylating agent. Because the enzyme showed comparable conversion yield and enantioselectivity in [BMIM][PF6] and hexane in a 24-h reaction, more work focused on these two reaction media. Comparison of the activity, stability and enantioselectivity of CRL was carried out by examining the effects of the mole ratio of substrates, temperature, incubation time and enzyme recycling. It was found that temperature control was more crucial in the ionic liquid than in hexane to reach high conversion and enantioselectivity. The ionic liquid system showed an advantage of using less acid anhydride to achieve higher (±)-menthol conversion yield and better enantioselectivity. Moreover, during an incubation of 4–60 days in the ionic liquid, CRL activity was 2.5 times higher than its initial value, while that in hexane decreased to less than 60% in 2 days. In addition, the enzyme showed potentiality of recycled use in the ionic liquid. These advantages of the ionic liquid suggest that it would be used as a green alternative to organic solvents for the enantioselective esterification of (±)-menthol.  相似文献   

6.
为了解纤维素在咪唑类离子液体中的降解行为,用正交试验法分析了温度、转速、时间对纤维素降解程度的影响,并比较了纤维素在四种离子液体中的降解行为。结果表明,纤维素在1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)中的最佳溶解条件为,温度80℃,时间1h,转速230r/min。温度对纤维素降解程度影响最大,其次为时间和转速。同条件下,纤维素在[EMIM]Ac中的降解最轻,在1-烯丙基-3-甲基咪唑氯盐([AMIM]Cl)中降解最严重。没食子酸丙酯可显著缓解纤维素在离子液体中的降解程度。[EMIM]Ac、1-丁基-3-甲基咪唑醋酸盐([BMIM]Ac)遇没食子酸丙酯显紫红色,并在纤维素溶解后颜色消失。  相似文献   

7.
Alternative solvents known as room-temperature ionic liquids (RTILs) were considered for extraction of organic soil contaminants. A hydrophobic RTIL, 1-butyl-3-methyl imidazolium hexafluorophosphate ([bmim]PF6), and a hydrophilic RTIL, 1-butyl-3-methyl imidazolium chloride ([bmim]Cl), were selected as representative imidazolium-based RTILs to assess the extraction of several organic contaminants (OCs) from two model soils. The two soils were montmorillonite (clay minerals, high surface area, and no organic matter) and glacial till (organic matter). The soils were spiked separately with DDT, dieldrin, hexachlorobenzene, and pentachlorophenol. With the exception of DDT, extractions of OCs from montmorillonite using [bmim]PF6 (79-92%) were nearly as effective as extractions with acetone and ethanol (85-100%). The extraction of OCs from glacial till with RTILs (15-61%) was less effective than extraction with organic solvents (59-100%). The [bmim]Cl was as efficient as [bmim]PF6 for extraction of OCs from glacial till, while [bmim]PF6 was more efficient than [bmim]Cl for extraction of OCs from montmorillonite. The two RTILs were most effective for the extraction of dieldrin (the heaviest OC) from both soils. The extraction results for glacial till showed dependence of OC extraction on the viscosity and melting point of RTILs.  相似文献   

8.
离子液体是一种完全由阳离子和阴离子所构成的物质,熔点低,在室温或低于室温下通常呈液态,具有诸多优良特性。离子液体可用作溶剂、光度法中的增敏剂、比色法中的显色剂、酯类化合物工业合成中的催化剂等。本文重点对离子液体在食品分离提纯、食品原料工业合成、生物技术三个方面的应用研究进展进行综述,分析了食品领域中离子液体的应用现状及存在的问题,并对发展前景做出了展望,为推动离子液体在食品工业中的应用研究和产业化提供参考。   相似文献   

9.
本文综述了纤维素在传统溶剂和新型溶剂——离子液体中的反应类型,总结了纤维素在传统溶剂和离子液体中的反应特点,着重阐述目前国内外纤维素在离子液体中各类反应的研究进展,最后总结了离子液体体系中纤维素均相反应和非均相反应机理。  相似文献   

10.
由于分子内或分子间的氢键作用,部分多糖难溶解于水或常规有机溶剂,因此限制了多糖在诸多领域的应用。而离子液体的出现则为难溶多糖的应用提供了可能。针对国内外关于离子液体溶解纤维素、甲壳素、壳聚糖等几种多糖的研究成果进行了综述,并对其溶解特性、溶解机理以及离子液体结构对多糖溶解特性的影响进行了探讨和总结,对今后利用离子液体溶解多糖的研究方向进行了展望。   相似文献   

11.
Ionic liquids are being developed as a replacement for volatile organic solvents in a range of industrial applications. These liquids have a vanishingly small vapor pressure, making them an attractive alternative to the volatile organic solvents. However, a thorough assessment of the environmental impact of the use of ionic liquids requires a more complete understanding of their fate and transport in environmental systems. Toward this end, we measured the adsorption of the ionic liquid 1-butyl, 3-methylimidazolium chloride (Bmim CI) onto a range of surfaces meant to represent those commonly found in the near-surface environment. We measured adsorption onto the Gram-positive soil bacterial species Bacillus subtilis, onto gibbsite, onto quartz, and onto Na-montmorillonite. We conducted experiments as a function of pH, solid:solute ratio, time, and ionic strength. The experimental results reveal that Bmim CI is unstable in water below pH 6 and above pH 10 and that it exhibits pH independent and ionic strength dependent adsorption onto Na-montmorillonite with 0.4, 0.8, 1.0, 1.2, and 2.0 g/L of clay. We observed no adsorption of the Bmim CI onto B. subtilis (3.95 or 7.91 g (dry weight) bacteria/L) at pH 5.5-8.5 or onto gibbsite (500 or 1285 g/L) or quartz (1000 and 2000 g/L) over the pH range 6-10. Calculated distribution coefficient (KD) values for Bmim CI onto the Na-montmorillonite change as a function of ionic strength; the 10(-4) M ionic strength KD value is 1735 +/- 269 L/Kg, and the 10(-1) M ionic strength KD is 1133 +/- 291 L/Kg. Our results suggest that the geologic retardation of this class of ionic liquid, if present as a dissolved contaminant in the subsurface, would be significant when a significant fraction of interlayer clays are present. However, adsorption onto other common geologic and biological surfaces is likely to be minimal, and the ionic liquids may travel unimpeded in groundwater systems in which these types of surfaces dominate.  相似文献   

12.
离子液体的合成及在萃取分离中的应用   总被引:2,自引:0,他引:2  
邵媛  邓宇 《皮革化工》2005,22(5):34-38
离子液体作为一类新型的环境友好的“绿色溶剂”,具有很多独特的性质,在很多领域有着诱人的应用前景。本文综述了离子液体的合成、检测、对高分子材料的溶解及降解性能及在萃取分离中的应用。  相似文献   

13.
The use of petroleum-derived solvents, particularly volatile organic compounds (VOCs), in the chemical industry has increased the contamination and residual effects of these solvents. Ionic liquids (ILs) can potentially replace VOCs, thereby reducing the risks of environmental contamination and toxicity. In this context, the objectives of this study were as follows: 1 — to obtain an ionic liquid for use in extracting carotenoids from tomatoes with ultrasound assistance; and 2 — to determine the stability and antioxidant activity of tomato carotenoid extracts. Ultrasound can also efficiently extract carotenoid compounds with ionic liquids in comparison with conventional VOC solvents (obtained from an all-trans-lycopene 7.5–8.0 μg·g 1 tomato sample by IL and 6.2–7.7 μg·g 1 by acetone). Similarly, the activation energies (Ea) in aqueous medium were obtained for the IL carotenoid extract (10.8 kJ·mol 1) and acetone carotenoid extract (9.4 kJ·mol 1). The antioxidant activities of the tomato carotenoid extract were 7.4 and 12.4 relative to α-tocopherol for the ionic liquid extract and acetone extract, respectively. The combination of chromatographic analysis and degradation kinetics provided data for positive assessment similarity of thermal and light stabilities of tomato carotenoids extracted by IL and extracted by acetone.  相似文献   

14.
酱油发酵酱醅中筛选到一株戊糖片球菌,对该菌的生长温度、生长pH值、食盐耐受度等生长特性进行研究。采用离子交换色谱法对该菌株产有机酸的情况进行测定;将该菌株添加到低盐固态酱油后酵过程中,以不添加乳酸菌的实验组作对照,对酱油样品理化指标、经济指标进行分析,并采用顶空固相微萃取-气相色谱-质谱法(HS-SPME-GC-MS)对酱油挥发性香气成分进行对比分析。结果表明,该乳酸菌的生长条件与酱油酱醅发酵环境相适应,其发酵产酸以乳酸和乙酸为主,与酱油中有机酸主成分相一致,将该菌株用于低盐固态酱油发酵,对酱油香气和其他指标均有不同程度的促进作用。  相似文献   

15.
The aim of this study was to examine the physicochemical surface properties and the ability to adhere to stainless steel of three strains of Listeria monocytogenes after different cultivation procedures. To this end, bacteria were cultivated at 37 degrees C after storage at two frequently used temperatures (4 degrees C or -80 degrees C) and were then transferred into the liquid medium (trypticase soy broth supplemented with 6 g liter(-1) of yeast extract, pH 7.3) between one and four times. In addition, the influence of supplementing the growth medium with lactic acid was explored, this organic acid being representative of both the dairy and cured meat industries. The hydrophobic/hydrophilic and electron-acceptor/electron-donor characteristics of the strains were evaluated by the microbial adhesion to solvents method. Using this technique, we recorded an increase in the hydrophobic properties of one strain stored at 4 degrees C, with an increasing number of transfers in the media (P < 0.05). Another plant-isolated strain appeared more hydrophobic and stuck better to stainless steel when cells were stored at 4 degrees C rather than at -80 degrees C. Preculturing L. monocytogenes in a lactic acid-supplemented medium increased the affinity of microbial cells to solvents and the bacterial attachment to stainless steel (P < 0.05).  相似文献   

16.
Abstract: In this research, a microextraction technique based on ionic liquids (ILs) termed in situ solvent formation microextraction (ISFME) was used for determination of nickel in solutions. 1‐(2‐pyridylazo)‐2‐naphtol (PAN) was chosen as a complexing agent. After preconcentration, the settled IL‐phase was dissolved in 50 μL of ethanol and aspirated into the flame atomic absorption spectrometer (FAAS) using a home‐made microsample introduction system. Injection of 50 μL volumes of analyte into an air–acetylene flame provided very sensitive spike‐like and reproducible signals. ISFME is based on phase separation phenomenon of ionic liquids in aqueous solutions. This method is simple and rapid for extraction and preconcentration of metal ions from food samples and can be applied for the sample solutions containing very high concentrations of salt. Furthermore, this technique is much safer in comparison with the organic solvent extraction because of using ionic liquid. The effective parameters such as amount of IL, salt effect, concentration of the chelating agent and ion pairing agent were inspected by a full factorial design to identify important parameters and their interactions. Next, a central composite design was applied to obtain optimum point of the important parameters. Under the optimum conditions, the calibration graph was linear over the range of 2 to 80 ng/mL. The limit of detection and relative standard deviation (n= 6) were 0.6 ng/mL and 2%, respectively.  相似文献   

17.
为了更好的研究工业乳酸发酵中的分解代谢物阻遏效应,在实验室规模反应器对凝结芽孢杆菌混合碳源乳酸发酵进行不同通气量、p H、中和剂等条件的发酵特性研究,并研究了不同金属离子、渗透压等条件对饥饿状态下凝结芽孢杆菌自溶的影响。结果表明:凝结芽孢杆菌葡萄糖+海藻糖混合碳源乳酸发酵呈现明显的分解代谢物阻遏效应,且发酵可分为葡萄糖消耗阶段、有机酸消耗阶段和海藻糖消耗阶段。不同发酵条件在葡萄糖消耗阶段对菌体生长和乳酸生成影响较小,但对发酵后期海藻糖利用阶段菌体生长和乳酸合成有明显影响。在海藻糖消耗阶段,通气量为7.2 L/h时有较高的底物消耗速率和产酸速率;用NaOH作为中和剂在p H6.5时海藻糖消耗速率和乳酸生成速率均高于pH6.0,而p H5.5时不利用海藻糖且不生产乳酸;与NaOH作为中和剂相比,在p H6.5条件下Ca(OH)2作为中和剂使海藻糖消耗速率和乳酸生成速率分别提高21.0%和28.3%。发现Ca2+、Mg2+等二价离子确实对菌体自溶有一定的缓解作用,且Na+能在饥饿状态下维持菌体的活性,为研...  相似文献   

18.
徐永建  王皎 《中国造纸》2011,30(6):58-63
从离子液体结构、溶解反应条件对纤维素溶解的影响以及纤维素溶解前后的差异等方面总结了离子液体对纤维素的溶解能力,阐述了可能的溶解机理。从选取离子液体,确定反应条件的角度提出了提高纤维素溶解率的方法。介绍了以离子液体为溶剂制备磁性材料、吸附剂、生物膜等纤维衍生材料及其应用于相关领域的优势,展望了离子液体在制浆造纸废水处理、脱墨、制浆领域中的应用前景。提出了离子液体工业化存在的问题及离子液体的研究方向。  相似文献   

19.
Stimulatory or protective effects of organic acids at low concentrations, e.g. acetic and lactic acid, on microorganisms have previously been reported. Especially in case of Zygosaccharomyces bailii, a peculiar growth stimulation by these two acids has recently been noticed. In order to elucidate this interesting phenomenon, growth and fermentative metabolism of Z. bailii was investigated in media with low pH (pH 4.0), high sugar (15% (w/v)) and different acetic and lactic acid concentrations. At both experimental temperatures (7 and 30 °C), a growth stimulation in the presence of 2.5% (v/v) lactic acid was observed. Furthermore at 7 °C, the yeast exhibited another unusual behaviour as it grew much faster in media containing 1.25% (v/v) acetic acid than in the control (without any acid). Production of fermentative metabolites was also increased together with the enhanced growth at both temperatures. These possible stimulatory effects of acetic and lactic acid should be taken into consideration when the acids are used at low doses for food preservative purpose. Presence of the acids may stimulate Z. bailii growth and fermentative metabolism, particularly at refrigeration temperature, consequently resulting in an earlier spoilage.  相似文献   

20.
以新鲜红皮萝卜为原料,分别接种分离自自然发酵泡菜中的乳明串株菌、乳酸乳球菌、食窦魏斯氏、发酵乳杆菌、植物乳杆菌进行纯种乳酸菌发酵制作泡菜。通过测定泡菜的乳酸菌菌相、总酸度、感官评价、挥发性成分及有机酸,对分离自自然发酵泡菜中不同乳酸菌纯种发酵泡萝卜的风味进行研究。结果表明,发酵达到终点时,接种不同乳酸菌发酵的泡菜中大部分乳酸菌的活菌数相差不大,都在7.0lg CFU/m L左右,泡菜液中的乳酸菌几乎全为植物乳杆菌;大部分乳酸菌纯种发酵泡菜中总酸含量>4g/kg;不同乳酸菌发酵的泡菜挥发性成分及有机酸的种类差异不显著。   相似文献   

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