室温离子液体中乙酸钠和氯苄催化合成乙酸苄酯

在多种1,3-二烷基咪唑和烷基吡啶室温离子液体中考察了较温和条件下乙酸 钠和氯化苄作用合成乙酸苄酯反应。在反应温度下（60 ℃）,熔融的三水合乙酸 钠与离子液体相混溶,氯苄同乙酸钠作用得到乙苄酯,它与四氟硼酸1-乙基-3-甲 基咪唑离子液体不溶而分层。反应结束后产物乙酸苄酯可直接倾析得到,乙酸苄酯 产率达到90%,纯度超过99%。此离子液体催化体系简化了产物分离,离子液体可以 重复使用。     

Pd/羧基功能化离子液体选择性催化氧化苯乙烯

 利用羧基对咪唑型离子液体的阳离子进行功能化,得到一系列具有不同羧基数目及与不同阴离子搭配的N-羧基功能化咪唑离子液体(TSILs), 进而构筑PdCl2/TSILs催化剂体系. 以过氧化氢为氧化剂,将PdCl2/TSILs用于选择性催化氧化苯乙烯合成苯乙酮. 研究结果表明, PdCl2/TSILs催化体系对目标反应具有理想的催化性能,羧基功能化离子液体的阳离子及其搭配的阴离子对苯乙酮的选择性和产率均有显著的影响. 阳离子的羧基数目越多,阳离子的不对称性越高, PdCl2/TSILs催化剂体系的活性越好. 含有相同阳离子的PdCl2/TSILs催化剂体系,其催化性能按照阴离子PF-6＜H2PO-4＜Cl-＜BF-4的顺序递增且与其酸强度顺序相反. 含有三羧基的功能化离子液体与PdCl2构筑的催化剂体系具有最佳的催化性能,在55 ℃下,该催化剂体系的转换频率值达到125 h-1, 苯乙烯可以完全转化且苯乙酮的选择性为91%.     

脯氨酸离子液体催化Knoevenagel缩合反应(英文)

改进了1-丁基-3-甲基咪唑L-脯氨酸([bmim][Pro])功能化离子液体的合成路线,并将该离子液体用于催化含活泼亚甲基化合物与醛或酮的Knoevenagel缩合反应.在水介质中,室温下,该离子液体可快速催化上述Knoevenagel缩合反应,并选择性生成α,β-不饱和羰基化合物且分离收率可达到88%～97%.该脯氨酸离子液体循环重复使用6次后,催化活性没有明显的下降.此外,初步探讨了其催化过程机理.     

氯铝酸室温离子液体系中HCl促进的苯的烷基化反应研究

研究了少量HCL调变的氯铝酸室温离子液体超强酸催化体系中，苯与碳-12烯以及氯甲烷的烷基化反应，对于前一反应，以溶有HCL的氯铝酸室温离子液体为催化剂与没有HCL的相比，反应的产物分布不同，而后一反应过程中有HCL生成，与纯ALCL3作催化剂相比，催化活性显著提高，实验结果还表明，生成的烷基化产物不溶于离子液体，因而易于分离，催化剂可以重复使用。     

吗啡啉功能化酸性离子液体的合成、表征及其催化酯化性能

制备和表征了三种新型质子酸离子液体: 吗啡啉硫酸氢盐([Hnhm]HSO4)、4-甲基吗啡啉硫酸氢盐 ([Hnmm]HSO4)和SO3H-功能化的4-(3-磺丙基)吗啡啉硫酸氢盐([C3SO3Hnhm]HSO4). 以氯乙酸(CAA)和乙醇合成氯乙酸乙酯的酯化反应考察了它们的酸性和催化活性, 并与1-(3-磺酸基)丙基-3-甲基咪唑硫酸氢盐、1-(3-磺丙基)吡啶硫酸氢盐、1-(3-磺丙基)-2-吡咯烷酮硫酸氢盐等三种具有不同氮杂环的SO3H-功能化酸性离子液体以及浓硫酸相对照. 结果表明, 上述SO3H-功能化离子液体对酯化反应的催化性能比非SO3H-功能化的[Hnhm]HSO4和[Hnmm]HSO4都高, 等同甚至优于浓硫酸. 当反应条件为: n(EtOH)∶n(CAA)∶n([C3SO3Hnhm]HSO4)＝1.3∶1∶0.2, 反应温度80 ℃, 反应时间3 h, 酯收率可达93.4%. 而且离子液体经真空干燥重复使用9次, 催化活性仍无明显下降. 以[C3SO3Hnhm]HSO4催化乙酸和不同醇的酯化反应获得较高的酯收率和选择性, 离子液体跟酯产物均能自动分相. 还考察了SO3H-功能化酸性离子液体对奥氏体316不锈钢的腐蚀性. 尽管SO3H-功能化离子液体与硫酸的酸性相近, 但对钢试样的腐蚀率不到硫酸的1/3.     

用环境友好催化剂俣成丙酸苄酯的研究

应用环境友好催化剂H－β沸石催化苯甲醇与丙酸的酯化反应,合成了丙酯苄酯。研究结果表明,H－β沸石 具有较高的催化活性。考察了苯甲醇／丙酸摩尔比、催化剂用量、反应温度、反应时间和带水剂环己烷用量对酯产率的影响。在典型反应条件（苯甲醇／丙酸摩尔比＝1.15:1、10.5gH－β沸石/摩尔丙酸、反应温度160℃ 、反应时间3.5h和20mL环己烷／摩尔丙酸）下,所得丙酸苄酯的产率为77％,该催化剂易于回收且可重复使用,具有良好的活性稳定性,并研究了用某些金属阳离子改性的β沸石的催化活性。     

烷基磺酸酯基功能化离子液体的合成、性质及其在酯化反应中的应用(英文)

采用廉价易得的原料合成了阳离子含有烷基磺酸酯官能团的功能化离子液体,并考察了其热稳定性.该离子液体可催化羧酸的酯化反应,其催化活性高于阳离子非功能化的离子液体,而与磺酸功能化离子液体相当.同时采用电喷雾电离质谱考察了该离子液体在酯化反应中的作用.     

Brφnsted酸性离子液体催化合成长链脂肪酸甲酯

本文合成了以1-丁基-3-甲基咪唑为阳离子,HSO4-、H2PO4-和BF4-为阴离子的Brφnsted酸性离子液体,并以长链脂肪酸与甲醇的酯化反应考察了这些Brφnsted酸性离子液体的催化性能。实验结果表明,1-丁基-3-甲基咪唑硫酸氢根鎓盐([bmim][HSO4])离子液体具有很高的催化活性,当n(醇)∶n(酸)∶n(离子液体)=6∶1∶0.25,反应温度为70℃,不分水酯化反应2h,长链脂肪酸甲酯的产率可达到93.4%以上,选择性达到100%;且产物酯与离子液体分离容易;离子液体经干燥处理后可以循环使用5次以上,催化活性没有明显降低。     

离子液体超酸清洁催化苯的烷基化反应

研究了在具有Lewis酸性的离子液体体系中进行的苯与烯烃及卤代烃的烷基化反应.以氯化1-甲基-3-乙基咪唑(MEIC)、氯化1-丁基吡啶(BPC)、氯化l-甲基-3-丁基咪唑(MBIC)及盐酸三甲胺(TMHC)季铵盐分别与AlCl3原位合成法制备离子液体催化体系.结果表明:以上各种离子液体均有很高的催化活性,反应转化率在较短的时间内达到100%.其中TMHC-A1Cl3离子液体单烷基化选择性达98.6%.与AlCl3相比,催化活性显著提高,生成烷基化产物不溶于离子液体,因而易于分离,催化剂可重复使用.     

磺酸功能化双核离子液体催化合成双酚F

合成并表征了4种具有Brnsted酸性的磺酸功能化咪唑类离子液体催化剂,考察了其在催化苯酚、甲醛合成双酚F反应中的催化活性.结果表明磺酸功能化双核离子液体双-(3-磺酸丙基-1-咪唑)亚丁基硫酸氢盐([DPSIM][HSO4]2)不仅催化活性最佳,还提高了4,4’-双酚F异构体的含量.以[DPSIM][HSO4]2为催化剂,在苯酚与甲醛摩尔比30∶1、离子液体催化剂质量浓度6.8%、反应温度90℃、反应时间60 min的优化条件下,双酚F收率可达94.1%,同时提出了其催化合成双酚F的反应机理.该离子液体催化剂腐蚀性低,易分离回收,在重复使用6次后,双酚F收率仍在70%以上.     

微波加热和常规加热下功能化离子液体催化合成丁二酸二辛酯

分别在微波辐射和常规加热下,以具有丙烷磺酸基功能基团的离子液体为催化剂催化丁二酸和正辛醇 合成丁二酸二辛酯,考察了其阴、阳离子对催化剂活性的影响.相比常规加热,微波加热提高了反应效率,缩短了反应时间.以[ PyPS]HSO4为催化剂,研究了催化剂用量、醇酸比和反应时间对酯化率的影响.结果表明:当催化剂用量为丁二酸的3wt％,酸醇比(丁二酸∶正辛醇)1∶4,反应温度150℃,反应时间15 min,功率400W时,酯化率达到95.74％.此外,微波辐射下[PyPS]HSO4催化剂重复使用6次后活性没有明显降低,酯化率仍有93.58％.     

Determination of benzyl alcohol and its metabolite in plasma by reversed-phase high-performance liquid chromatography.

A study undertaken following recent reports of deaths in neonatal children associated with the use of benzyl alcohol resulted in the development of a stability-indicating high-performance liquid chromatographic assay of benzyl alcohol in plasma using benzocaine as internal standard. Thawed plasma samples were diluted and subjected to solid-phase extraction using Extrelut and eluted with ethyl acetate. The evaporated eluate was reconstituted with mobile phase and chromatographed on a C18 column with water-acetonitrile-glacial acetic acid as mobile phase and detection at 254 nm. Baseline separation was achieved within 12 min for benzyl alcohol, benzaldehyde, benzoic acid, hippuric acid and benzocaine. Peak-height ratios were linear over 80-640 ng of benzyl alcohol injected (r = 0.998) and over 10-80 ng of benzoic acid injected (r = 0.999). Benzaldehyde and hippuric acid were not quantitated because these compounds were not detectable in actual dog plasma. Validation studies by spiking dog plasma with benzyl alcohol and benzoic acid gave overall percent recoveries (+/- relative standard deviation, n = 4) of 98.3 +/- 3.0 and 101.4 +/- 7.6%, respectively. The method was applied to the assay of actual plasma samples. Since benzyl alcohol is very susceptible to oxidation to benzaldehyde and benzoic acid, its purity in bulk liquid samples can be determined by this method.     

Determination of acetic acid in aqueous samples, by water-phase derivatisation, solid-phase microextraction and gas chromatography

The direct derivatisation of acetic acid with n-hexyl chloroformate and with benzyl bromide in water was evaluated. With n-hexyl chloroformate, acetic acid did not give the n-hexyl acetate derivative, but the reaction of acetic acid with benzyl bromide in aqueous solution resulted in the formation of benzyl acetate. The derivatisation of acetic acid with benzyl bromide and the headspace solid-phase microextraction (SPME) of benzyl acetate were optimised. Under optimum conditions, the limit of detection for acetic acid was 260 nM, and the relative standard deviation of the overall procedure at 1.10(-4) M acetic acid was 15.6% (n = 10). A linear response was obtained in the 1 x 10(-4) to 5 x 10(-6) M concentration range (R2 = 0.993, n = 6). Although Carbowax-divinylbenzene (CW-DVB)-coated fibres exhibited a higher extraction capacity for benzyl acetate, polyacrylate (PA) was selected, because its mechanical stability was better than that of CW-DVB fibres. Moreover, the relative standard deviation of the SPME was better with PA (1.5%, n = 10 at 1 x 10(-5) M) than with CW-DVB-coated fibres (8.0%, n = 10 at 1 x 10(-5) M). Thus, a new analytical method for the quantitative determination of micromolar concentrations of acetic acid in the aqueous phase was developed. This method is based on water-phase derivatisation with benzyl bromide, headspace SPME with PA fibres and GC-FID. It was observed experimentally that benzyl alcohol formed by hydrolysis of the reagent affected the fibre-gas phase partitioning of benzyl acetate.     

N-酯基取代吡啶功能化离子液体的合成与表征

合成了系列新型N-酯基取代吡啶功能化离子液体, 采用NMR、FTIR、ESI-MS、TG-DSC等表征手段, 对其结构组成和物理性质进行了全面的表征. 结果表明, 阴离子相同的N-酯基功能化离子液体与常规溶剂的相溶性基本相同, 由于酯基的引入, 这类离子液体与乙酸乙酯的相溶性降低. 含有相同阴离子的N-酯基吡啶功能化离子液体的熔点随着取代基碳链的增长逐渐下降, 阴离子为BF4、PF6的功能化离子液体具有较好稳定性, 热分解温度在300 ℃左右. 通过酯基对离子液体阳离子进行功能化, 可以对离子液体的物理、化学性能进行调变.     

硫酸氢钠催化合成羧酸苄酯

讨论了一水硫酸氢钠催化合成乙酸苄酯的条件。羧酸、苄醇和硫酸氢钠的质量比为 3∶2∶0 .1 45 ,以环己烷为溶剂 ,进行回流分水 ,合成了甲酸苄酯、乙酸苄酯、丙酸苄酯和丁酸苄酯 ,其收率为 68.5 %～ 84.1 %     

Secondary benzylation using benzyl alcohols catalyzed by lanthanoid, scandium, and hafnium triflate

The combination of a secondary benzyl alcohol and a metal triflate (e.g., La, Yb, Sc, and Hf triflate) in nitromethane was a highly effective secondary-benzylation system. Secondary benzylation of carbon (aromatic compounds, olefins, an enol acetate), nitrogen (amide derivatives), and oxygen (alcohols) nucleophiles was carried out with a secondary benzyl alcohol and 0.01-1 mol % of a metal triflate in the presence of water. Secondary benzyl alcohols and nucleophiles bearing acid-sensitive functional groups (e.g., tert-butyldimethylsilyloxy and acetoxy groups and methyl and benzyl esters) could be used for alkylation. Hf(OTf)4 was the most active catalyst for this alkylation, and trifluoromethanesulfonic acid (triflic acid, TfOH) was also a good catalyst. The catalytic activity of metal triflates and TfOH increased in the order La(OTf)3 < Yb(OTf)3 < TfOH < Sc(OTf)3 < Hf(OTf)4. A mechanistic study was also performed. The reaction of 1-phenylethanol (4a) in the presence of Sc(OTf)3 in nitromethane gave an equilibrium mixture of 4a and bis(1-phenylethyl) ether (54). Addition of a carbon nucleophile to the equilibrium mixture gave alkylated product in high yield.     

Synthesis of butyrate using a heterogeneous catalyst based on polyvinylpolypyrrolidone

A heterogeneous polyvinylpolypyrrolidone supported Brønsted acidic catalyst ([PVPP-BS]HSO₄) was used to synthesize butyrate in this paper. The prepared catalysts were characterized by FT-IR, TG, and FESEM and their catalytic activity in butyric acid esterification with benzyl alcohol was investigated. The influencing factors such as the amount of catalyst, reaction temperature, and reaction time were carefully studied. Under the optimized condition with the butyric acid to benzyl alcohol mole ratio of 1: 1.2 and the reaction temperature of 130°C, the yield of benzyl butyrate reached 96.8 % within 4 h in the presence of 8 mass % of catalyst. Moreover, the catalyst could be reused six times without noticeable drop in activity. This catalyst was also used to synthesize other kinds of butyrates achieving the butyrate yield above 90 %.     

固体磺酸促进亚硝酸异戊酯催化氧化苯甲醇反应

 以亚硝酸异戊酯为催化剂, 通过固体磺酸的促进作用原位产生亚硝酰正离子, 实现了催化氧气氧化苯甲醇制备苯甲醛. 300 oC 处理的 Amberlyst 15 表现出较高的促进效果, 在 0.5 MPa O2, 80 oC 反应 2 h, 苯甲醇转化率和苯甲醛选择性可分别达到 90% 和 97%. 通过红外、热分析及酸碱滴定研究了不同方法制得的固体酸的差别及其对反应促进效果的影响, 并利用紫外-可见光谱和衍生化方法检测了亚硝酰正离子.     

Oxidation of benzyl alcohol by K<Subscript>2</Subscript>FeO<Subscript>4</Subscript> to benzaldehyde over zeolites

A novel and green procedure for benzaldehyde synthesis by potassium ferrate oxidation of benzyl alcohol employing zeolite catalysts was studied. The prepared oxidant was characterized by SEM and XRD. The catalytic activity of various solid catalysts was studied using benzyl alcohol as a model compound. USY was found to be a very efficient catalyst for this particular oxidation process. Benzaldehyde yields up to 96.0% could be obtained at the following optimal conditions: 0.2 mL of benzyl alcohol, 4 mmol of K₂FeO₄, 0.5 g of USY zeolite; 20 mL of cyclohexene, 0.3 mL of acetic acid (36 wt %), 30°C temperature, 4 h reaction time.