微波辐照合成固载咪唑鎓离子液体中间体:1-甲基-3-(3-三乙氧硅基丙基)咪唑氯鎓

采用家用微波炉,在无溶剂的状态下,以1-甲基咪唑和3-氯丙基三乙氧基硅烷为原料,合成了固载咪唑鎓离子液体中间体:1-甲基-3-(3-三乙氧硅基丙基)咪唑氯鎓。考察了微波辐照方式、辐照时间、微波功率以及投料比对产物收率的影响。与传统加热方法相比,微波辐照法不仅大大缩短了反应时间,而且提高了收率;为中间体1-甲基-3-(3-三乙氧硅基丙基)咪唑氯鎓离子液体的合成提供了一个快速、高效、环保绿色的方法。     

1-己基-3-甲基咪唑六氟磷酸盐离子液体的微波辅助合成与结构表征

采用1-溴代己烷和N-甲基咪唑为原料,微波辅助快速合成了溴化1-己基-3-甲基咪唑([HMIM]Br)中间体,此步反应产率可达到95%。通过将中间体和六氟磷酸钾进行离子交换,制备了离子液体1-己基-3-甲基咪唑六氟磷酸盐([HMIM]PF6),产率约为48%。与传统方法相比,反应时间极大地缩短。产物的结构经傅立叶变换红外光谱(FT-IR)、超导脉冲傅立叶变换核磁共振氢谱(1HNMR)和超导脉冲傅立叶变换核磁共振碳谱(13CNMR)确认,纯度经高效液相色谱法(HPLC)分析达到99.0%以上。     

溴化1-乙基-3-甲基咪唑氯化锌离子液体的合成、表征及催化性能

采用溴代乙烷与N-甲基咪唑为原料合成了中间体溴化1-乙基-3甲基咪唑,并与氯化锌反应制备了1-乙基-3-甲基溴化咪唑氯化锌盐。分别经1 HNMR、FT-IR、TG、DSC对离子液体进行了结构表征及热分析。将该离子液体用于尿素醇解合成碳酸二乙酯反应体系,考查了[EMIM][Br][Zn2Cl4]离子液体的催化性能,碳酸二乙酯的收率超过25%。     

D-生物素中间体酰亚胺的合成工艺研究

酰亚胺即顺-1,3-二苄基-5-[（1S,2S）-（＋）-苏式-1羟甲基-2-（对硝基苯基）-2-羟乙基]四氢-4H吡咯并[3,4-d]咪唑-2,4,6-三酮,系合成生物素的中间体.     

1,4-二叠氮-2,3-二叠氮甲基-2,3-二硝基丁烷的合成

以硝基甲烷为原料合成了1,4-二叠氮-2,3-二叠氮甲基-2,3-二硝基丁烷,总收率为37.8%。采用1HNMR﹑IR和MS对目标产物及中间体的结构进行了表征。在三羟甲基硝基甲烷的合成中,结合反应机理确定了氢氧化钙的用量为:n(CH3NO2)n(Ca(OH)2)=1001;通过对催化剂浓硫酸﹑三氟化硼—乙醚络合物和对甲苯磺酸的比较,得出对甲苯磺酸为中间体2,2-二甲基-5-羟甲基-5-硝基-1,3-二氧杂环己烷合成的较优催化剂;分别采用2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四硝酸酯和2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四对甲苯磺酸酯与NaN3反应,发现磺酸酯基易离去,叠氮化反应更易进行,收率较高;叠氮化反应的较优溶剂为DMSO。DSC分析表明,1,4-二叠氮-2,3-二叠氮甲基-2,3-二硝基丁烷的分解峰温为223.46℃。     

丝素蛋白在室温离子液体中的溶解与再生性能研究

室温离子液体1-烯丙基-3-甲基氯代咪唑和1-(2-羟乙基)-3-甲基氯代咪唑是丝素蛋白的新型良溶剂.丝素蛋白在1-烯丙基-3-甲基氯代咪唑和1-(2-羟乙基)-3-甲基氯代咪唑中的溶解度分别为14.5%(质量分数)(100℃)和8.0%(质量分数)(80℃).向离子液体丝素溶液中加入乙醇或正丁醇可获得再生丝素蛋白.XRD和FT-Raman研究表明再生丝素蛋白膜的构象主要是β-折叠结构.TGA数据表明再生丝素蛋白的热稳定性比天然丝素纤维有所降低,热失重残留物有所增加.同时,机械性能和溶失率分析结果显示从离子液体中再生的丝素蛋白表现出良好的湿态机械性能和优异的稳定性.     

微波辐射合成耐盐性羟乙基纤维素高吸水性树脂

以羟乙基纤维素为原料,丙烯酰胺和马来酸酐为接枝单体,N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸胺为引发剂,采用微波辐射技术合成一种新型耐盐型羟乙基纤维素-丙烯酰胺-马来酸酐接枝共聚高吸水性树脂,探讨了微波辐射功率、混合单体AM/MAA比例、羟乙基纤维素浓度、交联剂以及引发剂用量对树脂吸盐水能力的影响.最佳合成条件为:微波辐射功率为400W且间歇加热12min、AM/MAA摩尔比为0.45,羟乙基纤维素浓度为3.0%、交联剂用量为2.0%、引发剂用量为0.15%,制得的高吸水性树脂最大吸盐水率达167g·g-1.     

微波辐射下离子液体［RMIm］PF6（R=P, B, C6）的合成及其电导率研究

在微波辐射下,1-甲基咪唑分别与有机卤盐（1-溴丙烷、1-溴丁烷、1-溴己烷）在80℃回流加热10min,可制得咪唑类离子液体的中间体溴代1-丁基-3-甲基咪唑（[BMIm]Br）、溴代1-丙基-3-甲基咪唑（[PMIm]Br）、溴代1-己基-3-甲基咪唑（[C6MIm]Br）,进一步与HPF6在室温搅拌反应4h,制得憎水性的咪唑类离子液体[BMIm]PF6,[PMIm]PF6和[C6MIm]PF6。对这3种离子液体及其在不同有机溶剂如丙酮、甲醇、乙酸乙酯中的电导率进行测定,发现离子液体的电导率受咪唑上取代基种类、溶剂种类、浓度和温度的影响,取代基的链越长,体积越大,离子液体的电导率越小。并且随温度升高和浓度的增大,离子液体的电导率也增大。     

离子液体溴代1-丁基-3-甲基咪唑盐合成的红外光谱分析

本实验建立以红外光谱法,利用特征吸收频率处的红外吸收率测得合成离子液体1-丁基-3-甲基咪唑六氟磷酸盐的中间产物溴代1-丁基-3-甲基咪唑盐的含量,应用于探索1-丁基-3-甲基溴代咪唑盐合成的最佳反应条件,结果表明反应温度为65℃,时间50分钟时产物得率高。     

离子液体溴代1-丁基-3-甲基咪唑盐合成的红外光谱分析

本实验建立以红外光谱法,利用特征吸收频率处的红外吸收率测得合成离子液体1-丁基-3-甲基咪唑六氟磷酸盐的中间产物溴代1-丁基-3-甲基咪唑盐的含量,应用于探索1-丁基-3-甲基溴代咪唑盐合成的最佳反应条件,结果表明反应温度为65℃,时间50分钟时产物得率高.     

MDS-6制备离子液体最佳条件探索

以N-甲基咪唑,溴代正丁烷,四氟硼酸钠为原料,采用两步法合成咪唑基离子液体1-丁基-3-甲基咪唑四氟硼酸盐(bmimBF4),重点对产物的最佳合成方法、最佳反应时间、最佳反应温度进行了探索。实验结果表明,使用微波消解仪(MDS-6)能快速有效地合成离子液体,且最佳的合成条件为:当微波功率400W,甲基咪唑与溴代正丁烷的摩尔比为1∶1.1,反应时间45min,微波反应温度80℃时,中间体bmimBr的合成最理想;当bmimBr与NaBF4的摩尔比1∶1.2,微波反应温度65℃,反应时间60min时,离子液体bmimBF4产率达到90%左右。试验产物用IR进行了确认。所制备的离子液体为后面制备四氧化三铁纳米空心球做准备。     

Microwave induced in-situ active ion etching of growing InP nanocrystals

High quantum yield (47%) InP nanocrystals can be prepared without the need for post HF treatment by combining microwave methodologies with the presence of a fluorinated ionic liquid. Growing the InP nanocrystals in the presence of the ionic liquid 1-hexyl-3-methyl-imidazolium tetrafluoroborate (hmim BF4) allows in situ etching to be achieved. The optimization of the PL QY is achieved by balancing growth and etching rates in the reaction.     

Microwave hydrothermal synthesis and visible-light photocatalytic activity of γ-Bi2MoO6 nanoplates

γ-Bi₂MoO₆ nanoplates have been successfully synthesized by a microwave hydrothermal approach for the first time, by using Bi(NO₃)₃, NH₃ and MoO₃ as the starting materials. The influences of the various preparation parameters (including the pH value, reaction temperature, and holding time) on the phase formation and morphology development were investigated in detail. XRD and TEM results showed that γ-Bi₂MoO₆ nanocrystals were formed indirectly with an intermediate phase of Bi₂O₃ in the microwave hydrothermal and hydrothermal synthesis. However, the reaction condition in the microwave hydrothermal approach was milder compared with the hydrothermal method. The photocatalytic activity of the nanoplates was evaluated by the degradation of the methylene blue solution under visible-light irradiation.     

Synthesis of hierarchical ZnO nanobelts via Zn(OH)F intermediate using ionic liquid-assistant microwave irradiation method

ZnOHF nanobelts (NBs) were synthesized under microwave irradiation in the presence of ionic liquid, 1,2,3-trimethyl-imidazole tetrafluoroborate. The ranges of width, length and thickness of the NBs are ca. 500-800 nm, several micrometers and 100 nm, respectively. Porous polycrystal ZnO NBs with hierarchical structure were obtained after careful heat treatment of the intermediate ZnOHF at 400 °C for 2 h. The structural characters of the ZnO NBs were investigated by XRD, SEM, TEM, HRTEM and XPS measurements, and their absorption and photoluminescence properties were studied as well. The characterization results support the proposed reaction mechanism that the hierarchical ZnO NBs were produced via ZnOHF intermediate and subsequent removal of one of its decomposition products, ZnF₂, by hot water. This may be a facile method to fabricate porous ZnO NBs with hierarchical structure.     

The hydrothermal analogy role of ionic liquid in transforming amorphous TiO2 to anatase TiO2: elucidating effects of ionic liquids and heating method

In this study, the specific coexistence of water and ionic liquid being the lower temperature thermal annealing condition for anatase crystallization of amorphous titania at ambient pressure was found. The test ionic liquids were 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium tetrafluoroborate. After deep investigation, we found that there existed an analogy between our lower temperature thermal annealing treatment system (LTTAT) and hydrothermal treatment system. In LTTAT system, the ionic liquid played an important role in driving surface crystallization of amorphous TiO₂ to the anatase phase by retaining a suitable amount of water through a dissolution–crystallization mechanism. We could observe higher hydroxyl group ratio of hydroxylated titanium compound from X-ray photoelectron spectroscopy (XPS) data during initial thermal annealing period. The self-assembly ability of ionic liquid then lead to kinetical dehydration and crystallization of hydroxylated titanium compound around it during the following annealing process. Based upon this proposition, the effects of different types of ionic liquid and its amount, temperature effect, and heating method on anatase crystallinity, characterized by X-ray diffraction (XRD), were investigated. It was found that different temperatures and microwave heating effect were observed for different types of ionic liquid. From these observations, it was pointed out that we could get better anatase crystallinity and good photodegradation performance by using the system containing ionic liquid having higher water-adsorbing ability and microwave heating annealing.     

1,3-二正丁基咪唑六氟磷酸盐离子液体的微波辅助合成与结构表征

以三甲基硅烷咪唑和1-溴代正丁烷作为原料,采用未经改装的家用微波炉在无溶剂条件下经季铵化反应合成了中间体溴化1,3-二正丁基咪唑([DnBIM][Br]),此步反应产率可以达到92%.再将第一步制得的中间体与六氟磷酸钾经复分解反应,得到1,3-二正丁基咪唑六氟磷酸盐离子液体([DnBIM][PF6]),收率为68%.提...     

Microwave radiation as heating method in the synthesis of titanium dioxide nanoparticles from hexafluorotitanate-organic salts

Nanocrystalline anatase was obtained from ionic liquid-like precursors containing hexafluorotitanate-organic salts and less than 25 wt.% of water, and using boric acid as fluoride scavenger. Two alternative heating methods were explored using either a conventional oven or a domestic microwave apparatus. A significant reduction in the reaction time from 24 h to only few minutes was obtained using the microwave route. The as-prepared materials were characterized by X-ray diffraction, transmission electron microscopy, nitrogen sorption analysis, and attenuated total reflectance Fourier transformed infrared, X-ray photoelectronic and Raman spectroscopes. The convenience of using the microwave heating option was a function of the organic cation present in the precursor. Thus, organic ammonium cations containing only hydrocarbon substituents, such as diethylammonium, phenylammonium and benzyltrimethylammonium led to the precipitation of nanocrystalline anatase powder with high specific surface area (up to 120 m² g⁻¹) in a short processing time (1-3 min). Otherwise, alcohol and carboxylate functionalized cations decomposed under microwave treatment. Moreover, the choice of the organic cation allowed tuning several properties of the end material, such as particle size and pore morphology.     

Fast synthesis of nanostructured ZnO particles from an ionic liquid precursor tetrabutylammonium hydroxide

Microwave irradiation could allow a more efficient and homogeneous heating of the reaction mixture to result in a fast synthesis. We propose a facile route for the synthesis of ZnO particles from an ionic liquid precursor with the assistance of microwave heating in which the ionic liquid has multifunctions (adsorbing microwave and acting as solvent, reactant, template) in the particle formation process. It demonstrates that ZnO particles with uniform size and morphology could be synthesized from tetrabutylammonium hydroxide ionic liquid precursor by the microwave heating method. Room temperature photoluminescence spectroscopy is measured to reveal the optical property of the as-obtained products. Moreover, the photocatalytic activity of the synthesized ZnO particles for the degradation of Rhodamine B is investigated.     

Preparation of indium oxide powders by microwave plasma dehydration of indium hydroxide powders

Indium oxide was prepared from the dehydration of indium hydroxide using atmospheric-pressure microwave air plasma. Compared with the conventional thermal plasma processing that was performed with the vapor phase reaction, the solid-state reaction was attempted in this study because microwave plasma has an intermediate temperature that is comparable to the melting temperature of inorganic materials and between those of the electric furnace and the thermal plasma. The results were compared with those with the electric furnace and the thermal plasma. With both the microwave plasma and the electric furnace, the macro-morphologies of the raw material were maintained, which indicates successful dehydration. However, the micro-morphologies differed. The product of the microwave plasma had a smooth surface, whereas the product of the electric furnace had a cracked and rough surface. The cracks were regarded as the results of the poor diffusion of the dissociated water. In the microwave plasma, the high temperature and the fast heating rate enhanced the diffusion and controlled the formation of cracks. With the application of the thermal plasma, the nanoparticles were prepared due to the vaporization of the dehydrated material. Thus, the microwave plasma is considered applicable to the solid-state reaction accompanying degassing, without a change in the microstructure of the raw material.