Effective Ionic Radii and Hydration Volumes for Evaluation of Solution Properties and Ionic Adsorption

Evaluation of effective ionic radii and corresponding individual hydrated-ion volumes provides data required for interpretation of various ion-specific solution properties and for understanding of specificity of ion adsorption at electrode and colloid interfaces. Principles involved in assignment of intrinsic ionic radii and hydrated-ion volumes are comparatively reviewed and examined as a basis for discussion of electrostriction volume changes. Three examples are given of applications of procedures for evaluation of individual hydrated-ion radii and volumes: (a) partial molal volumes and isentropic compressibilities of a series of oxyanions of various structures; (b) steric effects in hydration of alkylammonium and pyridinium cations; and (c) role of ion-hydration effects in specificity of chemisorption of electron donative anions at electrode surfaces.     

Ionic liquid self‐assembled monolayer and ion exchange for surface force control

Adhesion and lateral force were controlled by the formation of a self‐assembled monolayer combined with the surface ion exchange of ionic liquids on a silicon surface. In this study, the functionalized imidazolium ionic liquids were designed and synthesized with the aim of controlling surface force. N‐[3‐(Trimethoxylsilyl)propyl] ethylenediamine molecules were first self‐assembled onto a surface as an anchor layer and then 1‐propionic acid‐3‐methylimidazolium chloride were successfully grafted onto the amino‐modified surface. The surface force was changed by surface ion exchange in various anionic solutions. The self‐assembly and ion exchange processes were detected by means of attenuated total reflectance‐Fourier transform infrared spectrometry and further confirmed by X‐ray photoelectron spectra. Adhesion and friction behaviors were systematically investigated by atomic force/friction force microscope. The results indicated that anions played a great role in determining surface properties. Furthermore, surface adhesion and friction can be possibly quantitatively determined by the counter‐anions on the surface. Copyright © 2011 John Wiley & Sons, Ltd.     

Comparison Between Two Different Synthetic Routes of Pyrrolidinium Functional Polymeric Ionic Liquids

Summary: Two separate synthetic routes of preparation of new pyrrolidinium-based polymeric ionic liquids were compared. The first method utilized the modification of a commercial poly(diallyldimethylammonium) chloride via a direct anion exchange with several anions. The second route involved the anion exchange leading to several diallyldimethylammonium ionic liquid monomers having different anions and a subsequent polymerization. The latter method is particularly interesting for attaining tunable copolymers according to the desired properties of PILs. Both methods successfully resulted in ionic liquid polymers that are finding their way in a wide range of emerging applications.     

两亲性嵌段共聚物的合成及其在离子液体中的自组装行为

采用阴离子开环聚合法合成了两亲性嵌段共聚物PLA-PEG-PLA.用FT-IR,1H NMR和GPC等手段对嵌段共聚物的结构组成进行了表征.两亲性嵌段共聚物在离子液体1-丁基-3-甲基咪唑六氟磷酸盐中能自组装成胶束,用透射电子显微镜观察了聚合物在离子液体中形成胶束的纳米结构.当疏水链长固定时,胶束的自组装形状主要依赖于亲水链的长度.两亲性共聚物在离子液体中可自组装成可控制结构的纳米胶束,这种纳米结构胶束在很多领域具有广泛的应用前景.     

[BIm]Cl/CuCl离子液体脱除MTBE中硫醇机制及性能研究

以N-丁基咪唑、HCl和CuCl为原料两步法合成了离子液体[BIm]Cl/CuCl,并用傅里叶变换红外光谱FT-IR和傅里叶变换离子回旋共振质谱FT-ICR MS对其结构进行表征。采用差热扫描量热仪DSC、FT-IR以及紫外可见光谱UV-vis对吸附硫醇的[BIm]Cl/CuCl进行分析,讨论了[BIm]Cl/CuCl吸附硫醇的作用机制。以[BIm]Cl/CuCl为吸附剂,采用吸附蒸馏工艺脱除MTBE中的硫化物,MTBE硫含量可降低至5 μg/g以下,吸附剂进行多次循环使用且脱硫效果无明显降低。     

咪唑阴离子型碱性离子液体的合成及其催化Knoevenagel缩合反应

设计合成了由1-丁基-3-甲基咪唑阳离子与咪唑阴离子搭配的[bmim]Im新型碱性离子液体并对其碱性进行研究.[bmim]Im离子液体的碱性与[bmim]OH的碱性接近且强于[bmim]OAc.在水溶液及室温条件下,2%的[bmim]Im离子液体对系列芳香醛与活泼的亚甲基化合物之间的Knoevenagel缩合反应具有较好的催化性能,目标产物的收率达到86%～95%,选择性为100%.同时,该催化剂体系具有良好的循环性能.     

改性Y型分子筛对硫醇硫醚的吸附脱除研究

通过液相离子交换法制备了Cu(I)Y、Ni Y、Ce Y分子筛,以XRD、低温N2吸附-脱附、NH3-TPD、吡啶红外Py-FTIR等方法对其进行物性表征。利用固定床技术、WK-2D微库伦仪及硫化学发光检测GC-SCD色谱评价了改性分子筛对于硫含量300μg/g模拟油(含硫化合物二丙硫醚、环己硫醇和1-庚硫醇与壬烷配制)及HDS汽油的吸附脱硫性能。结果表明,吸附剂对模拟油和HDS燃料油品中硫醇硫醚具有吸附效果,且改性后的分子筛在吸附脱硫过程中,强的B酸对于吸附脱硫有负作用,会使油品中硫醇硫醚发生催化反应,聚合的大分子硫化物遮盖及阻塞吸附活性位点,从而使吸附剂不能够完全地吸附硫化物,造成吸附硫容较小,而弱L酸无催化活性对吸附脱硫有正面影响。     

Coke removal of the HZSM-12 zeolite with different silica/alumina ratio

The coke removal of HZSM-12 zeolite deactivated in the reaction of n-heptane cracking was studied by thermogravimetry using two multiple heating rate integral kinetics models proposed by Ozawa-Flynn-Wall and Vyazovkin to obtain the activation energy of process of thermoxidation of coke. The results obtained by both models presented excellent accordance with the related literature. This revised version was published online in August 2006 with corrections to the Cover Date.     

离子液体催化脱除芳烃中微量烯烃的研究

以室温离子液体为催化剂,对芳烃中的微量烯烃杂质进行深度脱除。考察了离子液体种类、用量、温度等不同因素对烯烃脱除效果的影响。结果表明,[bmim]Br-AlCl₃离子液体显示了优良的催化性能,在离子液体的质量分数为5%、室温、反应10min下,溴指数从原料的773.5下降到10以下,芳烃中微量烯烃脱除率达到99%以上,离子液体可重复使用,并对反应机理进行了研究。     

Ionic and dipolar solvation dynamics in liquid water

The solvation time correlation function for solvation in liquid water was measured recently. The solvation was found to be very fast, with a time constant equal to 55 fs. In this article we present theoretical studies on solvation dynamics of ionic and dipolar solutes in liquid water, based on the molecular hydrodynamic approach developed earlier. The molecular hydrodynamic theory can successfully predict the ultrafast dynamics of solvation in liquid water as observed from recent experiments. The present study also reveals some interesting aspects of dipolar solvation dynamics, which differs significantly from that of ionic solvation. Dedicated to Prof. C N R Rao on his 60th birthday     

Synthesis of La-incorporated chitosan beads for fluoride removal from water

In this study, lanthanum incorporated chitosan beads (LCB) were synthesized using precipitation method and tested for fluoride removal from drinking water. The effect of various parameters like complexation and precipitation time, lanthanum loading and ammonia strength on fluoride removal have been studied. It is observed that the parameters for the synthesis of LCB have significant influence on development of LCB and in turn on fluoride removal capacity. The optimal condition for synthesis of LCB includes lanthanum loading: 10 wt%, complexation time: 60 min, precipitation time: 60 min, drying temperature: 75 °C for 72 h. The maximum fluoride adsorption capacity of LCB was found to be 4.7 mg/g and negligible release of lanthanum ion was observed. XRD analysis shows the presence of lanthanum hydroxide and amorphous nature of LCB. SEM of LCB shows the presence of oval lanthanum hydroxide particles spread over the chitosan matrix. Fluoride adsorption capacity has been calculated by applying Langmuir and Freundlich isotherms. The comparative study suggests that LCB shows four times greater fluoride adsorption capacity than the commercially used activated alumina.     

Comparison of different imidazolium supported ionic liquid polymeric phases with strong anion-exchange character for the extraction of acidic pharmaceuticals from complex environmental samples

Two imidazolium supported ionic liquid phases (SILPs) containing different anions, trifluoromethanesulphonate [CF(3) SO(3) (-) ], and tetrafluoroborate [BF(4) (-) ], were synthesized and evaluated as solid-phase extraction sorbents for extracting acidic pharmaceuticals from aqueous samples under strong anion-exchange conditions, which include an effective cleanup of the sample. The best SILP material [MI(+) ][CF(3) SO(3) (-) ] was selected and successfully applied to the determination of acidic pharmaceuticals in different types of water samples (river water and effluent wastewater). The results were then compared to the previously synthesized SILP material based on [MI(+) ][CF(3) COO(-) ] and the commercially available Oasis MAX sorbent.     

Preparation of Mesoporous Molecular Sieves AI-MSU-S Using Ionic Liquids as Template

Mesoporous molecular sieves A1-MSU-S has been prepared from the precursor of zeolite Y using ionic liquids1-hexadecane-3-methylimidazolium bromide(CMIMB)as a template in basic medium,which exhibited larger porediameter,pore volume and surface area than that synthesized using cetyl trimethyl ammonium bromide(CTAB)template.     

Ionic liquid: An efficient and recyclable medium for the synthesis of fused six-membered oxygen heterocycles

The investigation for replacement of organic solvents in chemical synthesis is a growing area of interest due to increasing environmental issues. The use of ionic liquid salts as solvents and catalysts in organic reactions has gained extensive interest. Ionic liquids provided a new environmentally benign and improved alternative to traditional methods in modern synthetic chemistry. The aim of present review is to focus on the applications of ionic liquids for the synthesis of fused six-membered oxygen heterocycles.     

丙酮+环己烷+甲醇组成的最低共沸混合物热力学性质的研究

Mesoporous molecular sieves Al-MSU-S has been prepared from the precursor of zeolite Y using ionic liquids 1-hexadecane-3-methylimidazolium bromide （CMIMB） as a template in basic medium, which exhibited larger pore diameter, pore volume and surface area than that synthesized using cetyl trimethyl ammonium bromide （CTAB） template.     

以N为中心的阴离子离子液体的合成、表征及应用

首次通过不同阴离子的钾盐和不同的季铵化的咪唑,吡咯溴盐/氯盐进行离子交换,合成了一系列含氰基官能团的阴离子功能化离子液体。通过红外、核磁共振、质谱对离子液体的结构进行表征;通过TGA对离子液体的热稳定性进行测定,结果发现功能化离子液体具有良好的热稳定性,其分解温度在224-289℃范围内。将功能化离子液体[EMIm][N(CN)COC2H5]作为配体应用于无膦配体的Suzuki偶联反应,发现在反应中加入功能化离子液体[EMIm][N(CN)COC2H5]可以使反应收率提高10-20%。     

不同模板剂含量MCM-49分子筛的CTAB修饰及在苯甲醚酰基化反应中的应用

芳香族化合物的Friedel-Crafts酰基化反应是制备芳香酮的一类重要反应,传统的Lewis酸(如AlCl3)和质子酸(如H2SO4)催化剂易制备,价格便宜,但存在对环境污染严重、与产物难分离等问题.因此,近年来研究者一直致力于环境友好催化剂的研发,其中分子筛因选择性好、与产物易分离、可再生和无污染等优点而日益受到人们的重视,尤其是MWW分子筛,由于具有较多的外表面酸性位,而在酰基化反应中表现出良好的抗积碳性能.本课题组曾讨论了对一系列不同模板剂(六亚甲基亚胺, HMI)含量的MCM-49分子筛进行NaOH与十六烷基三甲基溴化铵(CTAB)共处理的情况,而本文重点考察的是只用CTAB处理不同HMI含量的MCM-49分子筛时,其结构与酸性会如何变化,改性前后样品的结构与酸性借助XRD, N2吸脱附等温线测试,29Si与27Al MAS NMR, NH3-TPD, Py-IR与漫反射傅里叶变换红外光谱(DRIFTS)等技术进行表征.另外,将一系列样品用于催化苯甲醚(AN)与乙酸酐(AA)的酰基化反应,考察CTAB处理对MCM-49分子筛催化性能的影响.将含模板剂HMI的MCM-49分子筛原粉在不同温度(250,350,450或550°C)下焙烧,得到一系列不同孔道系统内保留HMI的样品,随后采用CTAB溶液(0.27 mol/L)对其在70°C下进行后处理1 h.结构表征的结果表明,在脱除模板剂HMI及CTAB处理的过程中,分子筛骨架结构基本未被破坏,同时, CTAB处理不能向分子筛中引入任何形式的介孔,无论是晶内介孔还是晶间介孔.在CTAB处理时,可以清除分子筛中部分无定形物种,尤其是无定形Al物种,同时也可能发生部分非骨架Al原子重新进入分子筛骨架的情况,造成骨架铝的比例相对提高.根据29Si与27Al MAS NMR结果可以推断,进入分子筛骨架的Al原子可能会取代T3位置上的Si原子,亦或直接进入T2或T3位置缺陷位.酸性表征的结果表明, CTAB修饰后样品Br?nsted酸量比HMCM-49明显提高,并随HMI含量的逐渐降低呈现先增加后降低的趋势,而Lewis酸量则相对于HMCM-49有所降低.将一系列CTAB修饰前后的MCM-49样品用于催化AN与AA的酰基化反应,反应条件为：压力1.0 MPa、温度110°C、总质量空速WHSV(AN+AA)为10.2 h?1及原料中AN与AA的摩尔比为5：1.反应数据表明,相对于HMCM-49样品, CTAB修饰后样品对应的AA转化率显著提高(初始转化率由51.4%最高增加至85.0%),并随CTAB处理过程中HMI含量的逐渐降低呈现先增加后降低的趋势,而产物选择性则基本没有变化.各样品的AA初始转化率与其Br?nsted酸量基本呈现正向关联.通过间二甲苯歧化反应预积碳堵塞超笼及碱性探针分子2,4-二甲基喹啉吸附覆盖表面半超笼的方法,研究CTAB修饰前后各样品的不同孔道系统对酰基化反应的催化贡献.结果表明,酰基化反应主要发生在MCM-49分子筛的表面半超笼,其次为超笼,正弦孔道的贡献很小.另外, CTAB修饰后样品催化活性的提高主要来自于不含HMI的孔道系统的贡献,进一步验证在CTAB处理过程中,改性作用主要发生在MCM-49分子筛中不含HMI的区域.结合表征和反应评价结果,提高酰基化反应活性需尽可能提高催化剂的Br?nsted酸量,这是分子筛催化剂今后改进的一个主要方向.     

离子液体-水的混和溶剂中，纳米TiO2的制备与表征

以钛酸正丁酯为前驱物，采用溶胶-凝胶低温水热方法，以离子液体(1-乙基-3-甲基咪唑醋酸盐)和水为混合溶剂，制备了锐钛矿相的纳米二氧化钛。产物经XRD，TEM，N₂吸附-脱附等表征，结果表明与纯水相比，混和溶剂中制备的二氧化钛具有较高的纯度，结晶度和热稳定性，且缩短反应时间到24 h，所得颗粒尺寸10 nm与在纯水中反应48 h所得颗粒尺寸7 nm相当，说明离子液体的存在可促进锐钛矿相二氧化钛的结晶和生长。另外，该产物表面积可达238 m²·g^-1。本文还进一步研究了该产物对甲基橙水溶液的光降解作用，结果表明，用此方法制备的TiO₂对甲基橙降解作用优于商业P25二氧化钛。     

含氰基基团的以C为中心的不对称阴离子离子液体的合成、表征及应用

首次通过不对称阴离子的钠盐/钾盐和不同的季胺化的咪唑,吡咯溴盐/氯盐进行离子交换,合成了一系列含氰基官能团的不对称阴离子功能化离子液体。通过红外、核磁共振、质谱和元素分析对离子液体的结构进行表征;通过TGA对离子液体的热稳定性进行测定,结果发现不对称功能化离子液体具有良好的热稳定性,其分解温度在219-319℃范围内。将功能化离子液体[Bmim][C(CN)2COCH3]作为弱配体应用于模型的Suzuki偶联反应,发现在反应中加入功能化离子液体[Bmim][C(CN)2COCH3]可以使反应收率提高10-15%。