双酸位SO42-/ZrO2-SiO2固载离子液体催化剂的构筑及性能

采用一步共缩合-水热法合成酸性载体SO₄^2-/ZrO₂-SiO₂,化学法接枝酸性离子液体磺酸功能化咪唑硫酸氢盐（[Ps-im]HSO₄）,构筑拥有Brönsted与Lewis双酸位的离子液体固载型催化剂SO₄^2-/ZrO₂-SiO₂-IL。采用X射线衍射、傅里叶红外、N₂吸附-脱附、X射线光电子能谱、热重以及透射电镜对催化剂的结构进行表征,结果表明：锆原子和酸性结构SO₄^2-被成功引入纯硅材料,所合成的载体具有一定酸性;离子液体成功固载于酸性介孔材料SO₄^2-/ZrO₂-SiO₂,且固载后的催化剂保持其介孔结构。以大豆油和甲醇的酯交换反应为探针,考察了SO₄^2-/ZrO₂-SiO₂-IL催化剂的催化性能。在反应温度为150℃、反应时间为4 h、催化剂量5%（w/w）、醇油物质的量之比为24：1的反应条件下,生物柴油的收率超过92%,且回收利用5次后,生物柴油的收率仍达86%。     

酸性离子液体催化合成三吲哚甲烷化合物

在酸性离子液体催化下,通过吲哚及其衍生物和吲哚甲醛反应合成了一系列三吲哚甲烷化合物。[hmim]HSO₄/EtOH 对于该反应来说,是一个高效、绿色的催化体系。     

离子液体/水混合溶剂促进芳醛与罗丹宁的缩合反应

在室温条件下, 离子液体1-正丁基-3-甲基咪唑四氟硼酸盐([bmim]BF₄)与水组成的混合溶剂能有效催化一系列芳醛与罗丹宁反应, 以80%～93%的产率生成相应的5-芳亚甲基-2,4-噻唑二酮. 离子液体[bmim]BF₄催化活性高, 反应在10～120 min内完成. 实验结果表明该法反应条件温和、产率高、反应时间短、后处理简单、离子液体可重复使用.     

无溶剂条件下离子液体[Hnmp]HSO4催化一锅法合成2 -氨基苯并噻唑-芳甲基-2-萘酚

以离子液体[Hnmp]HSO₄为催化剂, 在无溶剂条件下催化芳香醛、2-氨基苯并噻唑和2-萘酚合成一系列的2 -氨基苯并噻唑-芳甲基-2-萘酚. 该方法条件温和, 反应时间短, 产率高和对环境友好. 此外催化剂可以方便地回收, 且循环使用四次其催化活性并没有显著降低. 目标产物经过了¹H NMR, IR, MS和元素分析确证.     

新型苯并噻唑离子液体的合成及其催化蓖麻油酸酯化研究

以价格低廉的苯并噻唑为原料,合成了4种新型功能化布朗斯特酸性离子液体:苯并噻唑硫酸氢盐([HBth]-HSO_4)、苯并噻唑磷酸二氢盐([HBth]H_2PO_4)、苯并噻唑高氯酸盐([HBth]ClO_4)、苯并噻唑硝酸盐([HBth]NO_3),其结构经FT-IR、HRMS、NMR表征得到确认.考察了4种酸性离子液体在蓖麻油酸和乙二醇丁醚(EGBE)酯化反应中的催化活性,并与以浓硫酸为催化剂的催化体系相对照.结果表明:当n(蓖麻油酸)∶n(乙二醇丁醚)=1∶1.15,离子液体催化剂用量为蓖麻油酸重量的2%,反应温度90℃,反应时间5 h,酯化率可达98.8%,离子液体催化剂经真空干燥重复使用10次后,仍具有较高的催化活性.还考察了以苯并噻唑硫酸氢盐为催化剂催化合成系列蓖麻油酸二元醇醚酯和短链脂肪酸酯,也获得了较高的酯化率,且离子液体均能与酯产物自动分相.与传统硫酸催化酯化相比,此类离子液体催化酯化具有生产成本低、过程清洁、使用周期长等优点,完全可以替代传统浓硫酸催化蓖麻油酸酯化反应.     

酸性离子液体中铂纳米粒子的制备、表征及应用

基于功能化离子液体的特性,开发出不使用聚合物保护剂制备铂纳米粒子并同时获得具有金属和酸活性中心双功能催化剂的新方法。首先,设计并合成出了一种新型季铵型质子(Br?nsted)酸性离子液体(N, N, N-三甲基-N-磺丁基硫酸氢铵([HSO₃-b-N(CH₃)₃]HSO₄)),然后,利用化学还原方法在该离子液体中制备了金属铂纳米粒子,并采用紫外光谱、傅立叶红外光谱、X-光电子能谱、透射电子显微镜和X射线衍射等方法对所制备的金属铂纳米粒子进行了结构表征。结果表明,所制备的铂纳米粒子具有面心立方结构,离子液体作为修饰剂修饰在铂纳米粒子的表面,有效地阻止了铂纳米粒子的团聚;将该含有铂纳米粒子的酸性离子液体作为双功能催化剂,直接用于硝基苯加氢合成对氨基苯酚反应,发现其具有良好的催化性能,在85 ℃、4 h、0.4 MPa条件下,硝基苯转化率为98.6%,对氨基苯酚收率为75.8%,回收的酸性离子液体纳米铂双功能催化体系中铂纳米粒子依然具有很好的分散性和稳定性。     

离子液体促进四氟硼酸铜催化芳醛和乙酸酐合成1,1-二乙酸酯

在室温条件下, 离子液体1-正丁基-3-甲基六氟磷酸盐([bmim]PF₆)能促进四氟硼酸铜催化一系列芳醛和乙酸酐反应, 以83%～97%的产率生成相应的1,1-二乙酸酯. 在离子液体[bmim]PF₆存在情况下, 催化剂活性远远高于无离子液体存在下的活性. 催化剂用量仅需 0.2 mol%就能使反应顺利进行, 远远少于文献报道的其它催化剂的用量, 反应在3～20 min内完成. 实验结果表明该法催化剂用量少、产率高、反应时间短、离子液体可重复使用、对环境友好.     

酸性离子液体催化脂肪酸甲酯聚合制备二聚酸甲酯

 以 Brönsted-Lewis 酸性离子液体为催化剂, 用于催化生物柴油中不饱和脂肪酸甲酯聚合制备二聚酸甲酯反应, 考察了催化剂种类、催化剂用量、反应温度和时间等因素对聚合反应性能的影响, 得到较佳的反应条件. 结果表明, 当以 1-(3-磺酸)-丙基-3-甲基咪唑氯锌酸盐[HO3S-(CH2)3-mim]Cl-ZnCl2 (ZnCl2 摩尔分数为 0.67) 为催化剂, 生物柴油 15 g, m(生物柴油):m(离子液体) = 15:1, 于 240 oC 下反应 6 h 时, 二聚酸甲酯收率为 63.2%, 其中三聚体含量小于 5%. 另外, 该催化剂重复使用 5 次后, 二聚酸甲酯收率仍超过 63%, 表明其具有较好的重复使用性能. 离子液体的 Brönsted 和 Lewis 酸位的协同效应显著提高了其催化活性.     

微波促进酸性离子液体催化水杨酸酯化

用自制的硫酸氢1-甲基-3-(3-磺酸基丙基)咪唑([MIMPS]HSO4)酸性离子液体作为水杨酸与醇的酯化反应催化剂,考察了温度、时间、物料配比和离子液体用量等因素对酯化反应的影响,优化的最佳反应条件为: 微波辐射时间20 min,反应温度95 ℃,醇与酸摩尔比3∶1(水杨酸的量为0.02 mol),[MIMPS]HSO4用量10 mmol,水杨酸甲酯的产率和选择性分别为91.9%和99.0%。 离子液体回收循环使用4次,催化效率不变。 与热催化酯化反应相比,微波辐射可缩短反应时间;水杨酸与不同碳链醇的酯化产率随着碳链的增加而降低,同碳链的伯醇酯化率比仲醇高。     

高活性离子液体催化棉籽油酯交换制备生物柴油

 制备了五种对水稳定性好、带-SO3H 官能团的Bronsted酸离子液体,并用它们催化棉籽油酯交换反应制备生物柴油. 结果表明,磺酸类Bronsted酸离子液体具有很好的催化活性,其催化活性与阳离子中的含氮官能团和碳链长度有关,吡啶丁烷磺酸硫酸氢盐离子液体的催化活性最好,其活性接近于浓硫酸催化剂. 离子液体容易同产物分离,具有很好的稳定性,可以循环使用,对环境友好,是制备生物柴油的较理想催化剂.     

Magnetic Solid Base Catalyst Fe3O4@Gly Used as Acid‐Resistant Catalyst for Biodiesel Production

Fe₃O₄@Gly nanoparticles were synthetized by coprecipitation and studied in the transesterification of soybean oil and methanol to determine its performance for biodiesel synthesis. The magnetism and catalytic performance of Fe₃O₄@Gly alkaline catalyst were investigated in detail. With a catalyst dosage 1.5 wt %, methanol/soybean oil ratio of 15:1, reaction temperature of 65 °C, and a reaction time of 3 h, the highest yield of biodiesel was 95.8%. The strong base catalyst CaO was used as comparison, from which it was seen that Fe₃O₄@Gly was more hydrophobic than the former. Moreover, because of the complete dissolution of oleic acid in methanol, Fe₃O₄@Gly could make better contact with oleic acid, which made it perform far better than pure CaO in oleic acid. In addition, after four times recycling, the yield of biodiesel was still 86.6%. The results show that Fe₃O₄@Gly possesses excellent properties of acid resistance and recyclability. The catalyst can be a high‐efficiency alkaline heterogeneous catalyst for biodiesel production.     

Greener approach: Ionic liquid [Et3NH][HSO4]-catalyzed multicomponent synthesis of 4-arylidene-2-phenyl-5(4H)oxazolones under solvent-free condition

We have developed simple, greener, safer multicomponent synthesis series of 4-arylidene-2-phenyl-5(4H) oxazolones 4(a-r) catalyzed by Bronsted acid ionic liquid as triethylammonium hydrogen sulfate [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate with excellent yields (90–99%). The protocol offers economical, environmentally benign, solvent-free conditions, and recycle–reuse of the catalyst and easily available starting as benzoyl chloride 1, amino acid 2 and a variety of aldehydes 3. The cyclization followed by condensation of benzoyl chloride, amino acid, and a variety of aldehydes catalyzed by ILs [Et₃NH][HSO₄] and catalytic amount of acetic anhydride and sodium acetate. The final products were confirmed by their characterization data such as FTIR, ¹H-NMR, ¹³C-NMR, Mass, high-resolution mass spectra and were compared with its reported method.     

Performance and Mechanism of Alkylimidazolium Ionic Liquids as Corrosion Inhibitors for Copper in Sulfuric Acid Solution

The addition of corrosion inhibitors is an economic and environmental protection method to prevent the corrosion of copper. The adsorption, performance, and mechanism of three 1-alkyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO₄, [HMIM]HSO₄, and [OMIM]HSO₄) ionic liquids (ILs) on the copper surface in 0.5 M H₂SO₄ solutions were studied by quantum chemical calculation, quantitative structure-activity relationship (QSAR), and molecular dynamics simulation. It is found that the main reactive site is located on the imidazolium ring (especially the C2, N4, and N7 groups). When the alkyl chain of the imidazolium ring is increasing, the molecular reactivity of the ILs and the interaction between the ILs inhibitor and copper surface are enhanced. The imidazole ring of the ILs tends to be adsorbed on Cu (111) surface in parallel through physical adsorption. The order of adsorption energy is [Bmim]HSO₄ < [Hmim]HSO₄ < [OMIM]HSO₄, which is in agreement with the experimental order of corrosion efficiency. On the imidazole ring, the interaction between the copper surface and the C atom is greater than that between the copper surface and the N atom. It is found that ILs addition can hinder the diffusion of corrosion particles, reduce the number density of corrosion particles and slow down the corrosion rate. The order of inhibition ability of three ILs is [Bmim]HSO₄ < [Hmim]HSO₄ < [OMIM]HSO₄,which agree well with experimental results. A reliable QSAR correlation between the inhibition corrosion efficiency and molecular reactivity parameters of the ILs was established.     

Aza‐Crown Ether Complex Cation Ionic Liquids: Preparation and Applications in Organic Reactions

Aza‐crown ether complex cation ionic liquids (aCECILs) were devised, fabricated, and characterized by using NMR spectroscopy, MS, thermogravimetric differential thermal analysis (TG‐DTA), elemental analysis and physical properties. These new and room‐temperature ILs were utilized as catalysts in various organic reactions, such as the cycloaddition reaction of CO₂ to epoxides, esterification of acetic acid and alcohols, the condensation reaction of aniline and propylene carbonate, and Friedel–Crafts alkylation of indole with aldehydes were investigated carefully. In these reactions, the ionic liquid exhibited cooperative catalytic activity between the anion and cation. In addition, the aza‐[18‐C‐6HK][HSO₄]₂ was the best acidic catalyst in the reactions of esterification and Friedel–Crafts alkylation under mild reaction conditions.     

Sol–Gel Entrapped Lewis Acids as Catalysts for Biodiesel Production

Replacing fossil fuels with biodiesel enables the emission of greenhouse gases to be decreased and reduces dependence on fossil fuels in countries with poor natural resources. Biodiesel can be produced by an esterification reaction between free fatty acids (FFAs) and methanol or by transesterification of triglycerides from oils. Both reactions require homogeneous or heterogeneous catalysis. Production of biodiesel catalyzed by heterogeneous catalysts seems to be the preferred route, enabling easy product separation. As we have previously shown, the Lewis acids AlCl₃ and BF₃ can serve as highly efficient catalysts under ultrasonic activation. The present study focused on the development of oleic acid (OA) esterification with methanol by the same catalysts immobilized in silica matrices using the sol–gel synthesis route. During the course of immobilization, AlCl₃ converts to AlCl₃ × 6H₂O (aluminite) and BF₃ is hydrolyzed with the production of B₂O₃. The immobilized catalysts can be reused or involved in a continuous process. The possibility of biodiesel production using immobilized catalysts under ultrasonic activation is shown for the conversion of FFAs into biodiesel in batch and continuous mode.     

Catalytic performance of acidic ionic liquid-functionalized silica in biodiesel production

Acidic ionic liquid ([BsAIm][OTf]) was immobilized on sulfhydryl-group-modified SiO₂ (MPS-SiO₂) via free radical addition reaction. The [BsAIm][OTf] loading on acidic ionic liquid-functionalized silica ([BsAIm][OTf]/SiO₂) was controlled through tuning the sulfydryl (SH) content of MPS-SiO₂. All the samples were characterized by FT-IR, elemental analysis, N₂ adsorption-desorption measurements and TG-DTA. The catalytic performance of [BsAIm][OTf]/SiO₂ in the esterification of oleic acid and the transesterification of glycerol trioleate for biodiesel production was investigated. The results showed that with the increase of [BsAIm][OTf] loading on SiO₂ the specific surface area and pore volume of [BsAIm][OTf]/SiO₂ decreased, and the pore diameter of [BsAIm][OTf]/SiO₂ narrowed. In the esterificaiton of oleic acid, the oleic acid conversion increased with the increasing [BsAIm][OTf] loading. In the transesterification of glycerol trioleate, with the increasing [BsAIm][OTf] loading the glycerol trioleate conversion decreased and the selectivities to glycerol monooleate and methyl oleate increased.     

吗啡啉碱性离子液体催化合成油酸甲酯

采用两步法合成了由阳离子N-甲基-N-丁基吗啡啉和阴离子氢氧根搭配的[Nbmm]OH新型碱性离子液体。实验利用FT-IR、元素分析和TGA分别对该离子液体的化学结构和热稳定性进行了表征。结果表明,该离子液体的热稳定性超过200℃。对该离子液体的溶解性能进行了考察, 结果表明,该离子液体能与强极性溶剂互溶,而且其水溶液的碱性较强。为了考察该离子液体对酯化反应的催化活性,实验过程中以油酸和甲醇反应生成油酸甲酯的酯化反应为模型反应,评价该离子液体的催化活性。结果表明,当反应温度60℃、酸醇比为1:6、离子液体加入量为原料总质量的15%、反应10 h时,油酸转化率达93.9%,而且该离子液体易于从反应体系中分离,可以循环使用。     

SO3H-Functionalized Ionic Liquids: Green, Efficient and Reusable Catalysts for the Facile Dehydration of Aldoximes into Nitriles

Easily synthesized aldoximes have been converted to the corresponding nitriles under very mild conditions by a simple reaction using two halogen‐free SO₃H‐functionalized ionic liquids, 3‐methyl‐1‐(4‐sulfonic acid)butylimi‐ dazolium hydrogen sulfate [MIM(CH₂)₄SO₃H][HSO₄] and 1‐(4‐sulfonic acid)butylpyridinium hydrogen sulfate [PY(CH₂)₄SO₃H][HSO₄], as catalyst and reaction medium without any additional organic solvent. The method was equally effective for aromatic aldoximes bearing electron‐donating and electron‐withdrawing substituents. Taking into account environmental and economical consideration, the protocol presented here has the merits of environmentally friendly, simple operation, easy work‐up and very good yields. The catalysts could be recycled and reused for several times without noticeably decreasing in their catalytic activities.     

Alkylation of phenol with isopropanol over MCM-49 zeolites

Four novel Br?nsted acidic ionic liquids with two different acid sites on the imidazolium cations were synthesized and employed as catalysts and media in the esterification of acetonitrile with alcohols. The results showed that [HSO₃-pHim]HSO4 was the most efficient catalyst and medium which could be recycled easily without obvious decline in the catalytic activity.     

Br?nsted-acidic ionic liquid [HO3S(CH2)4MIM][HSO4] as efficient and reusable catalyst for one-pot synthesis of β-acetamido ketones

Abstract  

Efficient and convenient synthesis of β-acetamido ketones has been achieved by one-pot reaction of acetophenone, aryl aldehydes, acetyl chloride, and acetonitrile in the presence of 3-methyl-1-(4-sulfonylbutyl)imidazolium hydrogensulfate [HO₃S(CH₂)₄MIM][HSO₄], a Br?nsted-acidic ionic liquid, as a green and reusable catalyst in solvent-free media at room temperature. The catalyst could be recycled and reused without noticeable decrease in catalytic activity.