碱性离子液体碱化制备N-十六烷基化壳聚糖

合成了1-甲基-3-丁基咪唑醋酸盐([Bmim]OAc)、1-甲基-3-丁基咪唑碳酸盐([Bmim]2CO3)及1-甲基-3-丁基咪唑氢氧化物([Bmim]OH)离子液体,由FT-IR、1HNMR、13CNMR和元素分析对结构进行了确证。首先用离子液体对壳聚糖碱化,再令碱化后壳聚糖与溴代十六烷进行烷基化反应,制备高取代度的N-十六烷基化壳聚糖。用FT-IR、XRD对烷基化产物进行了表征。考察时间、温度及物料配比对N-十六烷基壳聚糖取代度的影响,得到较佳的反应条件:n([Bmim]OH)∶n(壳聚糖原料)=3∶1,40℃碱化1 h,n(溴代十六烷)∶n(碱化后壳聚糖)=2∶1,烷基化反应温度85℃,反应时间3.5 h,在该条件下十六烷基壳聚糖的取代度达到75%以上。离子液体具有重复使用性,反应后的离子液体重复使用3次后,N-十六烷基壳聚糖的取代度仍>75%。     

碱性离子液体碱化制备N-十二烷基化壳聚糖

合成了1-甲基-3-丁基咪唑醋酸盐([Bmim]OAc)、1-甲基-3-丁基咪唑碳酸盐([Bmim]2CO3)及1-甲基-3-丁基咪唑氢氧化物([Bmim]OH)离子液体,由FTIR、1HNMR和元素分析对其结构进行了确证。首先,用离子液体对壳聚糖碱化,再用碱化后壳聚糖与溴代十二烷进行烷基化反应,制备了高取代度的N-十二烷基化壳聚糖。用FTIR、1HNMR、XRD对烷基化产物进行了表征。考察了时间、温度及物料配比对N-十二烷基壳聚糖取代度的影响,得到较佳的反应条件:n([Bmim]OH)∶n(壳聚糖原料)=3∶1,45℃碱化1 h,n(溴代十二烷)∶n(碱化后壳聚糖)=2∶1,烷基化反应温度80℃,反应时间3 h,在该条件下十二烷基壳聚糖的取代度达到81%以上。离子液体重复使用3次后,N-十二烷基壳聚糖的取代度仍大于80%。     

Properties and mechanism of a poly(ionic liquid) inhibitor contained bi-functional groups for bentonite hydration

Present polymer inhibitors depend on a major inhibitory group to restrain bentonite hydration, and monomer design is concerned to improve the inhibition and stability through complex copolymerization. Conveniently, a homopolymer (PIL-NH₂) that contained primary amine and cationic imidazolium as bi-functional groups was proposed, aiming to provide two synergistic inhibitory modes. Comprehensive methods were conducted to characterize the chemical structure and inhibitory performance of PIL-NH₂. The ζ potential absolute value of bentonite suspension was decreased by PIL-NH₂ from 28.7–33.3 mV to 4–7 mV, and the increment of bentonite particle size d₅₀ was observable from 1.83892 μm to over 200 μm. With water squeezed out, the lattice spacing d₀₀₁ of hydrated bentonite was reduced from 1.9070 to 1.2683 nm due to PIL-NH₂ intercalation. The ESEM images revealed that inhibited bentonite showed a tight structure with classical dehydration phenomenon, and the hydrogen bond between PIL-NH₂ and bentonite was further confirmed according to the FT-IR result. In mechanism analysis, the electrostatic attraction and hydrogen bond existed simultaneously for PIL-NH₂ to adsorb bentonite. The two adsorption modes from bi-functional groups were synergistic to improve inhibition remarkably. PIL-NH₂ maintained high performance during the whole hydration process, including crystalline hydration, osmotic hydration, and hydrated dispersion.     

Preparation and antimicrobial activity of sulfopropyl chitosan in an ionic liquid aqueous solution

To improve the solubility and antibacterial activity of chitosan and expand its applications, we synthesized sulfopropyl chitosan (SP‐CS) with various degrees of substitution (DSs) under mild and green reaction conditions in the aqueous solution of an ionic liquid by a green process. The chemical structures of the polymers were verified by Fourier transform infrared spectroscopy and ¹H‐NMR, and the thermal stability was studied by thermogravimetric analysis. After modification, the water solubility of chitosan was improved significantly, and SP‐CS showed excellent solubility in water at neutral pH. The antibacterial activities of the SP‐CSs with various DSs were systematically studied for the first time by the Oxford cup method and optical density method. The results suggest that the antimicrobial properties of SP‐CS were enhanced by the introduction of sulfopropyl and increased with increasing DS. The application of chitosan could be expanded, and SP‐CS has the potential to be used as a water‐soluble antimicrobial. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44989.     

Entanglement network of chitin and chitosan in ionic liquid solutions

Concentrated solutions of a chitin from squid pens and of two commercial samples of chitosan were successfully prepared by using an ionic liquid 1‐butyl‐3‐methylimidazolium acetate as a solvent. The dynamic viscoelasticity data for the solutions exhibited rubbery plateaus, indicating the existence of entanglement network of chitin and chitosan in the solutions. To characterize the network, the values of the molecular weight between entanglements (M_e) for chitin and chitosan in the solutions were determined from the plateau moduli. Then the values of M_e in the molten state (M_e,melt), a material constant reflecting the inherent nature of polymer species, for chitin and chitosan were estimated to be 1.7 × 10³ and 3.0 × 10³, respectively. It was found that there was a significant difference in M_e,melt between chitin and chitosan. Compared with other polysaccharides such as cellulose and agarose in terms of the number of monosaccharide units between entanglements (N_unit), chitin had significantly smaller N_unit of 8, while chitosan had equivalent N_unit of 19. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2439–2443, 2013     

Highly porous catalytic materials with Pd and ionic liquid supported on chitosan

Chitosan was used to immobilize phosphonium‐based ionic liquids, combined with silica particles, to prepare catalytic materials in the form of highly porous monoliths. These catalytic materials were studied for the hydrogenation of 4‐nitroaniline into p‐phenylenediamine in the presence of formic acid as hydrogen donor in a column reactor. Experimental conditions for the elaboration of the materials were evaluated by their impact on palladium sorption, on the structure of the materials, and on their catalytic efficiency. The concentration of chitosan in the initial solution and the size and concentration of silica particles had to be carefully chosen to elaborate homogeneous materials, with good mechanical resistance and stability in water. The chitosan characteristics and the type of ionic liquid immobilized in the material did not significantly affect the structure of the materials but proved to be crucial for their catalytic efficiency. Higher catalytic performances were obtained using materials prepared from chitosan of high‐deacetylation degree and with Cyphos IL‐101. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Using ionic liquid catalyst for conversion of waste polyethylene terephthalate and soybean oil to polyester polyol

An imidazolium ionic liquid was synthesized, characterized and used as a catalyst for conversion of polyethylene terephthalate (PET) and soybean oil to polyester polyol (PE polyol). The degradation of PET waste was carried out using glycerol and low cost soybean oil that resulted in the formation of PE polyols. Formed PE polyols were characterized using Fourier transform infrared (FT‐IR) and mass spectra method, thermo gravimetric and differential thermal analysis and gel permeation chromatoghraphy. The first step in the overall process is proposed to be the transesterification of soybean oil with glycerol to form monoglyceride or/and diglyceride of soybean oil fatty acids. In the second step, the obtained glycerides can react with PET to form PE polyol. Both steps could be combined in one process and acidic catalyzed by an ionic liquid. Ionic liquid can be used as active catalyst and show a high reusability. The influence of some factors such as amount of glycerol used in transesterification of soybean oil with glycerol, PET degradation time, and temperature on PET conversion were investigated to find the suitable conditions for the process. Under suggested optimum parameters (mass ratio of soybean oil to glycerol of 2:1, a time of 8 h and a temperature of 180 °C for PET degradation), a PET conversion of 87.3% was reached. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43920.     

Functionalization of chitosan via single electron transfer living radical polymerization in an ionic liquid and its antimicrobial activity

In this work, single electron transfer living radical polymerization (SET‐LRP) was used to functionalize chitosan in a well‐controlled manner. The chitosan‐based macroinitiator was first synthesized and then initiated the SET‐LRP of methacryloyloxyethyl trimethylammonium chloride (DMC) in ionic liquid system, using Cu⁰/N,N,N′,N′,N′′‐pentamethyldiethylenetriamine as a catalyst. The grafting of PDMC brushes on chitosan was confirmed and analyzed by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. Transmission electron microscopy reveals that the chitosan copolymer showed self‐assembled behavior in acetone. Surface properties of the copolymer have been investigated by environment scanning electron microscopy analysis. The linear relationship between the ln([M]₀/[M]_t) and time, the linear increase of number‐average molecular mass with conversion as well as the low polydispersity index of the polymer confirmed the “living/controlled” features of the polymerization of DMC through SET‐LRP. Finally, the chitosan copolymer demonstrates its potential antibacterial application, showing excellent inhibitive capability against Escherichia coli. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42754.     

Framework for correlating the effect of temperature on nonelectrolyte and ionic liquid activity coefficients

A power‐law expression is proposed for correlating the temperature dependence of infinite‐dilution activity coefficients ( ) for nonelectrolyte solute–solvent binary pairs and for pairs including an ionic liquid: , where θ_ij = 0 for Lewis–Randall ideal solutions, θ_ij = 1 for classic enthalpy‐based Scatchard–Hildebrand regular solution and van Laar models, and ?5 < θ_ij < 5 for most real binaries. The exponent θ_ij is a function of partial molar excess enthalpy ( ) and entropy ( ) such that . Real binaries are classified into seven types corresponding to distinct domains of and θ_ij. The new method provides a framework for correlating phase‐equilibrium driven temperature effects for a wide variety of chemical and environmental applications. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3675–3690, 2014     

Synthesis of chitosan derivative with dual‐antibacterial functional groups and its antibacterial activity

The O‐fumaryl ester (OFTMCS) of N,N,N‐trimethyl chitosan (TMCS) has been synthesized as a water‐soluble chitosan (CS) derivative bearing dual‐functional groups, with the aim of discovering novel CS derivatives with good water solubility and enhanced the antibacterial activity compared with unmodified CS. OFTMCS was characterized by FT‐IR, ¹³C NMR, XPS, XRD and Zeta potential analyses. The XPS results indicated that the degree of substitution (DS) on the C₂‐NH₂ group of the CS was 0.78, and that the DS on its C₆‐OH group was 0.31. The TGA results showed that the thermal stability of OFTMCS was lower than that of unmodified CS. The antibacterial activities of OFTMCS were investigated by assessing the mortality rates of the representative Gram‐positive and Gram‐negative bacteria Staphylococcus aureus and Escherichia coli, respectively. The results indicated that OFTMCS exhibited superior antibacterial activity to CS at a lower dosage. The synthesis of CS derivatives bearing dual‐functional groups could therefore be used as a promising strategy to enhance the antibacterial activity of CS. The antimicrobial mechanism of action of OFTMCS was discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42663.     

Synthesis and application of dicationic ionic liquids

Ionic liquids were synthesised that consisted of two methylimidazolium rings joined by a spacer 1–12 carbon atoms in length. The bis(triflic)imides with spacer ≤C₄ were solids; the others were liquid at room temperature. The polarity of the dication liquids and their performance in the extraction of phenol from water were compared with those of similar monocationic liquids. Copyright © 2005 Society of Chemical Industry     

绿色离子液体的合成与应用

离子液体作为一种新型绿色溶剂,目前被广泛应用于有机合成、溶剂、萃取和分离、电化学等领域。本文主要介绍了离子液体的特点和几种合成方法。分析比较了不同合成方法的特点,介绍了离子液体作为溶剂的原理和应用。     

新型碱性离子液体催化蓖麻油制备生物柴油

合成了新型碱性离子液体[Bmim]OH,将其应用于催化蓖麻油制备生物柴油,并与催化剂KOH、四丁基氢氧化铵进行比较,结果好于后两者。正交实验优化的碱性离子液体[Bmim]OH催化工艺条件为:催化剂用量为1%,醇油摩尔比为6∶1,反应温度为40℃,反应时间为60 min。在该优化条件下,甲酯混合物收率高于97%,蓖麻油基本上完全转化,其中高于95%转化为产物甲酯,催化剂[Bmim]OH重复使用6次没有明显消耗,催化性能稳定。     

N-甲基-N＇-（2-羟基-3-乙酰氧基丙基）咪唑盐离子液体的合成

离子液体作为一种新型的绿色溶剂和催化剂已引起了化学家们的极大关注。以乙酸钠和环氧氯丙烷为起始原料首先合成了乙酸缩水甘油酯,并优化筛选了乙酸缩水甘油酯的合成条件;再与无机酸质子化的N-甲基咪唑反应,制备了四个N-甲基-N’-（2-羟基-3-乙酰氧基丙基）咪唑盐新型离子液体。采用^1HNMR,IR和UV对新型离子液体的结构进行了表征。测定了新型离子液体的电导率及与常用有机溶剂之间的溶解性能。优化筛选试验结果表明,乙酸缩水甘油酯最佳的合成条件为：乙酸钠与环氧氯丙烷的摩尔投料比为1：1.5,甲苯作溶剂,四丁基溴化铵为催化剂,回流反应7h。     

Dynamically controlled fibrillation under combination of ionic liquid with mechanical grinding

Combination of mortar grinder mill (MG) and ionic liquid (IL) treatment was employed in order to fibrillate fibers from oil palm mesocarp fiber (OPMF) in one‐step. The structural changes of OPMF before and after the treatment were examined by Thermogravimetric analysis (TGA), Fourier transformed infrared (FT‐IR) spectra, Wide‐angle X‐ray diffraction (WAXD), Dynamic light scattering (DLS) and Scanning electron microscopy (SEM). Compared with the only use of 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIM[BF₄]), combination of MG and IL helped to remove hemicellulose and lignin components partially from OPMF, and also fibrillated OPMF fibers at average particle diameter of 127 nm. Afterwards, the fibrillated fibers were utilized as reinforcement material for the purpose of enhancement of mechanical properties of poly(?‐caprolactone)(PCL). The addition of OPMF treated with the combined method led to a 64% increase in tensile strength in comparison with that of untreated OPMF. These results indicate that the combined method enables effective fibrillation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44469.     

离子液体中壳聚糖磷酸吡哆醛席夫碱衍生物的合成与表征

引言壳聚糖是自然界中唯一含有氨基的碱性多糖,具有多样的生物活性、极好的生物相容性、生物可降解性以及无毒性等特性,是一种新兴的生物功能材料[1-3]。磷酸吡哆醛是维生素B6参与多种代谢反应的一种活性形式。磷酸吡哆醛作为一种辅酶参与所有转氨基反应及一些氨基酸的脱羧及脱氢反应。研究表明,磷酸吡哆醛不但可以用于预防治疗高血压、心血管疾病及糖尿病等,还可用于治疗迟发性运动障碍和治疗难治性儿童期癫痫[4-5]。王涛等[6]以壳聚糖微球为载体,然后固定磷酸吡哆醛等制备得到了低密度脂蛋白亲和吸附剂,用于去除高脂血症患     

聚合离子液体的合成及其吸附脱硫性能

以N-甲基二烯丙基胺与金属酞菁合成的功能化离子液体为单体、硅胶球为载体,在载体表面聚合制备成硅胶球负载的聚合功能化离子液体吸附材料[(NMDA-Pc/Ni²⁺)/SiO₂]。本研究采用红外光谱、X射线衍射、扫描电镜、偏光显微镜对其进行表征。考察了吸附剂在常压室温下对二苯并噻吩(DBT)的吸附脱硫性能。结果表明,(NMDA-Pc/Ni²⁺)/SiO₂的吸附脱硫性能最好。最佳吸附条件为吸附剂用量为1.5g/10mL模型油,吸附时间为20min,DBT的最大吸附量为6.198mg/g。该吸附剂对DBT的吸附行为遵循Freundlich吸附等温模型和拟二级动力学模型。以甲醇洗涤再生,重复使用5次后,吸附性能没有明显降低。烯烃和芳烃都会影响吸附剂的吸附脱硫效果,但芳烃对DBT选择性吸附的影响小于烯烃。吸附剂对不同的硫化合物也有良好的吸附作用,去除顺序为:二苯并噻吩>苯并噻吩>噻吩。     

离子液体支撑液膜应用研究进展

离子液体作为一种新型绿色介质,受到研究学者的广泛关注。离子液体具有不易燃、无味、无污染、无蒸汽压、可循环使用等独特性质,被广泛应用于化学化工过程中。离子液体用于膜分离技术具有不易挥发、稳定性好的特点,近来对离子液体在支撑液膜方面的研究备受关注,离子液体支撑液膜在污染性气体的吸收分离方面具有高选择性、高渗透性等优势,在有机物的分离方面具有分离效果明显、耐用性强等优势,在化学反应方面具有催化效率高、可循环使用等优势,本文介绍了离子液体支撑液膜的常用制备方法和膜基材料的选择,探讨了离子液体支撑液膜的稳定性和分离选择性的影响因素,对离子液体支撑液膜在气体分离、有机物的分离、化学反应等方面的应用研究进行了综述。     

微波辅助下离子液体中水杨酸酯的合成

在微波辐射功率为250 W反应25 min的条件下,水杨酸分别与甲醇、乙醇、丙醇、异丙醇、叔丁醇在离子液体作溶剂和催化剂下顺利发生酯化反应,以85%～95%产率得到了水杨酸甲酯、水杨酸乙酯、水杨酸丙酯、水杨酸异丙酯、水杨酸叔丁酯5种重要的有机合成中间体,该方法具有操作简单,催化剂可重复使用,反应时间短,对环境友好等优点。产物结构经1HNMR和元素分析确认。