酸性离子液体催化油酸酯化合成生物柴油简

酸性离子液体具有催化活性好、选择性高及易于回收等优点,是一种应用前景非常好的环境友好的酸性催化剂,在生物柴油合成反应中具有重大的理论意义和应用价值. 本文以油酸和甲醇为原料,探讨了7种不同酸性离子液体在生物柴油合成反应中的催化效应. 研究表明,离子液体酸性越强,催化酯化活性越高;引入磺酸基团可大大增强离子液体Brönsted酸性,使其在酯化反应中发挥溶剂/催化剂的双重作用,促进酯化反应向产物方向进行,达到高产率,因而1-丁基磺酸-3-甲基咪唑硫酸氢盐（[BHSO₃MIM]HSO₄）催化效果最好. 此外,系统研究了[BHSO₃MIM]HSO₄催化油酸与甲醇酯化反应,并采用响应面法优化了反应条件. 结果发现,该反应的最适醇酸摩尔比、催化剂用量、反应温度及反应时间分别为4：1,10%（基于油酸的质量）,130 ℃和4 h;在此条件下,生物柴油产率为97.7%. [BHSO₃MIM]HSO₄连续使用10批次后,仍能保持初始催化活性的95.6%,表现出极好的操作稳定性. 另外,利用该离子液体催化游离脂肪酸含量为72%的废油脂生产生物柴油,反应6 h可获得产率94.9%. 可见,[BHSO₃MIM]HSO₄在酯化生产生物柴油方面具有巨大的应用潜力.     

新型酸性离子液体[hmim]hso4中合成乙酸酯

制备了一种新型B rφnsted酸性离子液体[Hm im]HSO4,用于乙酸与醇的酯化反应,通过简单的相分离就可以实现产物乙酸酯与离子液体的分离。考察了温度、时间、物料配比、离子液体用量等因素对乙酸与正丁醇的反应的影响,得出反应的最佳条件为:反应温度110℃,反应时间2 h,酸醇摩尔比为2,酸性离子液体[Hm im]HSO4与醇的体积比为1,乙酸正丁酯的产率为97%。离子液体重复使用5次,乙酸正丁酯的产率均大于94%。利用核磁共振、红外和元素分析测试技术对酸性离子液体[Hm im]HSO4的结构进行了表征,是以一水合物的形式存在。测定了不同浓度[Hm im]HSO4水溶液的酸强度数据,结果表明,其酸性明显高于酸性离子液体[Hm im]CF3COO的酸性。     

己内酰胺对甲基苯磺酸离子液体中甲苯的选择性硝化反应

制备了一种低毒性的新型Brφnsted酸性离子液体己内酰胺对甲基苯磺酸([CP]PTSA)作为催化剂和溶剂,用于催化甲苯与等摩尔的体积分数为67%HNO3的硝化反应,用核磁共振、红外光谱对[CP]PTSA的结构进行了表征。考察了不同的反应温度、反应时间及催化剂用量等因素对甲苯硝化反应的产率和对位选择性的影响。得出最佳反应条件为:温度55℃,时间24h,离子液体用量占甲苯摩尔分数的20%,产物硝基甲苯中邻与对位异构体质量比为1.2,较硝-硫混酸硝化的相应比值(1.6)显著降低,硝基甲苯的产率达37.1%。离子液体重复使用4次仍表现出较好的催化活性及对位选择性。用质谱分析对回收的离子液体的结构进行了表征。结果表明,该离子液体的结构稳定。     

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.     

铌酸催化液相合成乙酸乙酯

报道了铌酸催化乙醇与乙酸的液相酯化反应考察了反应温度、催化剂用量、酸醇比、反应时间对产品乙酸乙酯经的影响。在优化条件下,产品收率棕达８８．０％,选择性为１００％,同时我们采用自制间式反应,对催化剂的稳定性进行了考察,发现铌酸在该实验条件下,能保持较高的稳定性和较高的催化活性。     

Importance of the diamine reactant in the production of polyphosphonamides by the interfacial technique

The stirred interfacial polycondensation of phenylphosphonic dichloride and 1,6-hexanediamine has been studied as a function of several reaction variables. The reaction is rapid, being completed in less than 1 min. When organic solvent is varied and reactant molar ratio is varied with an excess of the acid chloride, yield is constant. When reactant molar ratio is varied polymer yield increases with increase in amine concentration. When reactant concentration is increased yield increases. With the addition of a soluble salt in the aqueous phase yield is increased. The above indicates that the diffusion of the amine to the reaction zone is of primary importance in determining polymerization rate and that the diffusion of the acid chloride is relatively unimportant. Polymer yield was found to be dependent on the pH of the amine in the aqueous phase. The observed trend is related to the apparent solubility of the amine in the aqueous phase such that the greater the apparent solubility of the amine, the less the polymer yield. Polymer molecular weight is found to be independent of reaction variables tested. Polymer was also formed from the condensation of phenylphosphonic dichloride with p-phenylenediamine, H₂N-D-NH₂ (where D is a 36-carbon hydrocarbon chain), 1,3-di-4-piperidylpropane, and 4-aminomethylpiperidine; phenyl phosphorodichloridate with 1,6-hexanediamine; chloromethyl phosphonic dichloride with 1,6-hexanediamine.     

NaHSO4·H2O催化合成苯甲酸甲酯

以 Na HSO4 · H2 O催化苯甲酸与甲醇的酯化反应 ,合成了苯甲酸甲酯。研究结果表明 ,Na HSO4 · H2 O具有较高的催化活性。考察了苯甲酸 /甲醇摩尔比、催化剂用量及反应时间对酯产率的影响。在优化反应条件 [n(苯甲酸 )∶n(甲醇 )∶n( Na HSO4 ·H2 O) =1∶ 2∶ 0 .2 9,回流8h]下 ,苯甲酸甲酯产率达 85.3 %。     

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。     

二苯胺甲烷磺酸盐催化合成丙酸异戊酯

以二苯胺甲烷磺酸盐为催化剂,合成了丙酸异戊酯,考察了反应时间、催化剂用量、醇酸摩尔比等因素对酯化率的影响。结果表明,在最佳条件下,酯化率可达97．7％。     

Aerobic and Electrochemical Oxidative Cross‐Dehydrogenative‐Coupling (CDC) Reaction in an Imidazolium‐Based Ionic Liquid

The ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate [BMIm][BF₄] has demonstrated high efficiency when applied as a solvent in the oxidative nitro‐Mannich carbon? carbon bond formation. The copper‐catalyzed cross‐dehydrogenative coupling (CDC) between N‐phenyltetrahydroisoquinoline and nitromethane in [BMIm][BF₄] occurred with high yield under the described reaction conditions. Both the ionic liquid and copper catalyst were recycled nine times with almost no lost of activity. The electrochemical behavior of the tertiary amine substrate and β‐nitroamine product was investigated employing [BMIm][BF₄] as electrolyte solvent. The potentiostatic electrolysis in ionic liquid afforded the desired product with a high yield. This result and the cyclic voltammetric investigation provide a better understanding of the reaction mechanism, which involves radical and iminium cation intermediates.     

Novel Surfactant for the Reduction of CO2/Brine Interfacial Tension

The synthesis of novel CO₂ philic surfactant using maleic anhydride and dipropylene tertiary butyl alcohol is reported. The synthesis involved the esterification of maleic anhydride to produce bis(2-(2-(tert-butoxy)propoxy)propyl) maleate and subsequent sulfonation of the esterified product. Para toluene sulfonic acid was employed as catalyst for the esterification reaction. The esterification reaction was optimized for the maximum yield of 98% of bis(2-(2-(tert-butoxy)propoxy)propyl) maleate. The esterification reaction kinetics employing heterogeneous catalyst were also studied. Although this is a bimolecular reaction, a first order reaction kinetics with respect to acid has been observed. The activation energy was found to be 58.71 kJ/mol. The diester was followed by the sulfonation process and a yield of 85% of surfactant was achieved. The synthesized surfactant successfully lowered down the IFT between CO_2/brine to 1.93 mN/m. This surfactant has a great potential to be used for CO₂-EOR applications.     

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.     

A novel facile synthesis of carbamoylmethylphosphine oxides in ionic liquids

A convenient access to carbamoylmethylphosphine oxides (CMPO) in up to 96% isolated yield is developed via direct amidation of diphenylphosphoryl acetic acid in an ionic liquid as a recyclable reaction medium in the presence of triphenyl phosphite. The influence of the nature of the amine and anion and cation structure in the ionic liquid on the reaction rate and yields of the products are also investigated. 1-Butyl-3-methylimidazolium bromide [bmim]Br and trihexyltetradecylphosphonium chloride [P(C₆H₁₃)₃(C₁₄H₂₉)]Cl proved to be the best media for carrying out this reaction.     

Synthesis of Cationic Dumbbell-shaped Fullerene Nanostructures as Potential Photodynamic Sensitizers

A design of novel hydrophilic tetracationic dumbbell-shaped [60]fullerene nanostructures was made by balancing the hydrophilicity and hydrophobicity characteristics of the fullerene adduct for their potential application as photodynamic sensitizers in the PDT treatment. A sequential protection-deprotection reaction pathway was applied for the functional differentiation between primary and secondary amine moieties of pentaethylene hexamine. Synthesis of the target molecule involves two key steps of unsymmetrical esterification and amidation of malonic acid and subsequent fullerenation. The synthetic strategy was accomplished using mild reaction conditions in the intermediate molecule preparation and led a moderate overall product yield.     

羧基功能化离子液体催化合成1,5-苯并二氮衍生物

在无溶剂条件下,以邻苯二胺和丙酮为原料,羧基功能化离子液体CmmimBF_4(IL)为催化剂,合成了1,5-苯并二氮衍生物(2),其结构经~1H NMR和IR表征.在IL用量为10 mol%,于40 ℃反应1.5 h的条件下,2的产率达93%.IL无需再生处理,可连续循环使用5次,且活性无明显下降.     

甲酯化气相色谱法检测化妆品中防腐剂十一烯酸及其锌盐

采用硫酸催化甲酯化法检测了化妆品中的十一烯酸及其锌盐,并对甲酯化试剂、硫酸浓度、反应体系含水量、甲酯化温度、反应时间等条件进行了优化,发现反应体系的含水量对产率影响较明显。以5%硫酸甲醇溶液为甲酯化试剂,65℃水浴中反应1 h,正己烷为提取溶剂,采用GC/FID色谱法测定,外标法定量。十一烯酸甲酯产率达95%以上,该方法在0.05～1.0 mg范围内线性良好(r>0.999),检出限和定量下限分别为0.001 2%和0.004%。膏霜、乳液、化妆水和洗手液中十一烯酸的平均回收率为93%～104%,相对标准偏差为0.39%～5.1%。     

Catalysis of hydrosilylation,part XXII: Polymer-protected immobilized platinum complex catalysts for gas-phase hydrosilylation of acetylene

A platinum catalyst (hexachloroplatinic acid dissolved in ethanol) was immobilized by anchoring via amine and mercapto groups to silica followed by formation of a polymer layer which protected the catalyst against leaching. These catalysts (A and B) as well as precatalysts (S_A-Pt, S_B-Pt) which were not protected by polymer were tested in the gas-phase hydrosilylation reaction of acetylene with trichlorosilane. The catalytic parameters (yield 80%, selectivity 100%) obtained under optimal conditions prove the advantage of catalyst A over 300 h reaction time by the flow method.     

Production of acetic acid from liquid crystal display waste by use of a hydrothermal method

Because of the large quantity of liquid crystal displays (LCDs) in use, the volume of waste LCDs is ever-increasing, causing growing concern about their effective treatment. Polarizers are among the most important functional films used in LCDs and are mainly treated by incineration after being discarded. In this study, they were used to produce acetic acid under the hydrothermal conditions; this could aid development of a new environmentally sustainable process for treatment of waste polarizers. The experiment was performed in a 5.7-ml bath reactor heated by use of a salt-bath. The liquid product was analyzed by high-performance liquid chromatography. The effect of reaction temperature, reaction time, and oxidant on acetic acid production was investigated. Results showed that the yield and selectivity for acetic acid initially increased with increasing reaction temperature, reaction time, and H₂O₂ supply but then decreased within the ranges of the experiments performed. The highest acetic acid yield of 33.4 %, with selectivity of 26.7 % based on carbon, was obtained by hydrothermal treatment of waste polarizer at 350 °C for 5 min with 0.6 ml H₂O₂.     

An efficient protocol for synthesis of novel polyheterocyclic chromeno pyrimido[1,2-b]indazolone derivatives using [Et3NH][HSO4] as a reusable catalyst under solvent-free conditions

A convenient and highly efficient method for the synthesis of novel polyheterocyclic chromeno pyrimido[1,2-b]indazolone derivatives via a three-component condensation of 1H-indazol-3-amine, aldehydes and 4-hydroxycoumarin catalyzed by Bronsted acid ionic liquid [Et₃NH][HSO₄] under solvent-free reaction conditions is presented. This ionic liquid is air and water stable and easy to prepare from amine and acid. The main advantages of this protocol includes short reaction time, excellent yield, easy work-up, operational simplicity, a wide range of functional group tolerance and column chromatography-free method. The catalyst can be recovered and reused for at least four runs without any significant impact on the product yields.