酸性离子液体催化苯胺和二氧化碳合成二苯基脲

以苯胺和二氧化碳为原料催化合成二苯基脲是一条绿色工艺路线,重点对Lewis酸类离子液体催化该反应性能进行了研究。考察了一系列碱性和Lewis酸性催化剂的催化性能,以及溶剂对该反应的影响,结果表明,以无水AlCl₃为催化剂和乙腈为溶剂组成的反应体系效果较好。以氯铝酸类离子液体为催化剂兼溶剂,考察了离子液体阴阳离子、CO₂初始压力、反应时间、反应温度以及催化剂用量等因素对二苯基脲合成反应的影响。结果表明,以［Bmim］Cl-AlCl₃离子液体为催化剂兼溶剂,在CO₂初始压力为1 MPa、反应时间为7 h、反应温度为160℃、AlCl₃/苯胺质量比为1∶1的条件下,苯胺的转化率、二苯基脲的收率及选择性分别为18.1%、17.9%和98.9%。此外,提出了［Bmim］Cl-AlCl₃离子液体催化苯胺和二氧化碳的反应机理。     

Solventless synthesis of cyclic carbonates from carbon dioxide and epoxides catalyzed by silica-supported ionic liquids under supercritical conditions

A silica-supported ionic liquid proved to be an efficient heterogeneous catalyst for solventless synthesis of cyclic carbonates from epoxides and carbon dioxide under supercritical conditions, which requires no additional organic solvents either for the reaction or for the separation of product. The effects of reaction time, temperature and other reaction parameters on the reaction are investigated. High yields with excellent selectivity were obtained. The purity of product separated directly by filtration from the reaction mixture, reached 99% without further purification process. Moreover, the catalyst can be easily recovered by filtration and reused over four times with slight loss of its catalytic activity. The process represents a simple, ecologically safer, cost-effective route to cyclic carbonates with high product quality, as well as easy product recovery and catalyst recycling.     

碱性离子液体协同配合剂催化葡萄糖异构化制备果糖

糖类是生物质的重要组成部分，可经催化转化制得一系列高附加值化学品，具有经济价值高、对环境友好和可持续性强等优点。葡萄糖异构为果糖是该过程的关键步骤。本文合成了四种碱功能性离子液体，用红外光谱、核磁共振谱仪和热重分析进行了表征，并用于催化葡萄糖异构化制备果糖，结果表明碱性离子液体具有较好的催化活性，但易使果糖进一步催化降解，同时加入硼酸钠可提高葡萄糖的转化率和果糖的产率，说明硼酸钠既起配合保护剂的作用，也有一定的协同催化作用。考察了离子液体用量、硼酸钠用量、时间、温度等因素对果糖选择性和产率的影响，结果表明，在离子液体和硼酸钠与葡萄糖的摩尔比分别为3∶1和0.08∶1、反应温度为70℃、反应时间为7 min的最佳反应条件下果糖的产率可高达64.7%，选择性为73.1%。     

Quaternary Ammonium Ionic Liquids as Bi-functional Catalysts for One-step Synthesis of Dimethyl Carbonate from Ethylene Oxide,Carbon Dioxide and Methanol

Abstract  

One kind of novel ionic liquids (ILs) with a tertiary amino moiety and a quaternary ammonium group were synthesized and identified by FT-IR, ¹H and ¹³C NMR. The elemental chemical state and basicity of ILs were determined by XPS and Hammett indicator method, respectively. Then the catalytic performance of these bi-functional catalysts was investigated in one-step synthesis of dimethyl carbonate (DMC) from ethylene oxide (EO), carbon dioxide and methanol. The best catalytic performance with 99% EO conversion and a maximum of 74% DMC selectivity was obtained using [N_111,6N11]I as catalyst under optimized reaction conditions. And the catalyst could be reused for several times. Normally, stronger basicity could be obtained by altering the anions with different nucleophilicity in ILs and a better catalytic activity could be achieved correspondingly. A mechanism that both the ring opening of epoxide through nucleophilic attacks and the transesterification play an important role in the reaction was proposed based on experimental results.     

Novel Brønsted acidic ionic liquids based on benzimidazolium cation: Synthesis and catalyzed acetalization of aromatic aldehydes with diols

In this article, a new group of Brønsted acidic task-specific ionic liquids based on benzimidazolium cation was synthesized and used as environmentally benign catalysts for acetalization of aromatic aldehydes with diols. Hammett method had been used to determine the acidity order of these ionic liquids, which was consistent with the catalytic activities observed in acetalization reaction. Maximum substrate conversion of 98% and product selectivity of 100% were obtained using [PSebim]HSO₄ as catalyst, which could be reused at least 10 times without obvious loss of catalytic activity.     

Effect of cocatalyst and carbon dioxide pressure on the synthesis of polycarbonate from phenyl glycidyl ether and carbon dioxide

The copolymerization of phenyl glycidyl ether (PGE) and carbon dioxide was performed in the presence of ionic liquid catalyst. 1-Butyl-3-methyl imidazolium chloride, tetrabutylamouim chloride and 1-n-butylpyridinium chloride were used as catalyst for this reaction carried out in a batch reactor. All the ionic liquid catalysts showed good catalytic activity for the synthesis of polycarbonates with very low polydispersity, close to 1. The carbonate content, turnover number (TON), and average molecular weight of the copolymer were affected by the structure of the ionic liquid. High carbon dioxide pressure enhanced TON and carbonate content because of the increase of carbon dioxide absorption in PGE solution. ZnBr₂ and a Zn-Co cyanide complex were also tested as a catalyst and/or cocatalyst for this reaction to compare their catalytic performance with the imidazolium salt ionic liquids.     

Convergent Activation Concept for CO2 Fixation in Carbonates

Concepts to facilitate the conversion of epoxides with carbon dioxide to the corresponding cyclic carbonates commonly focus on the activation of the epoxide. Herein we report a catalytic system which allows the simultaneous activation of carbon dioxide and the epoxide. This convergent activation concept is realized by combining a suitable carbene as catalyst for the carbon dioxide activation with a second catalytic system based on potassium iodide for epoxide activation. Initial experiments showed synergistic effects and thus proving the feasibility of this activation concept. Moreover a standard protocol was developed and the substrate scope under these conditions has been studied. Under mild and solvent‐free conditions 14 epoxides could be converted. The respective cyclic carbonates were obtained in good to excellent yields with selectivities ≥ 99 % after simple filtration.

     

Lewis酸离子液体催化合成对甲氧基苯乙酮

合成并表征了Lewis酸离子液体,用于催化合成对甲氧基苯乙酮。通过考察各种离子液体的催化活性及重复使用性能,选定Lewis酸离子液体[Bmim]Cl-AlCl3为催化剂,研究了醇酸摩尔比、反应时间、反应温度等因素对酰化反应的影响,得到其较佳工艺条件:醇酸摩尔比1∶1.5,反应温度60℃,反应时间6 h。此条件下,酯化率达到78.8%。分离后的离子液体经真空干燥后重复使用5次,催化活性基本不变。     

离子液体催化的芳烃氯甲基化反应

Ionic liquids have been used as catalysts for Blanc reaction of toluene. The effects of reaction temperature, reaction time and dosage of the ionic liquid catalyst have been investigated, and the catalytic performance of different ionic liquid catalysts for toluene chloromethylation was also studied. The reaction was found to proceed under mild conditions with excellent conversion （up to 90%） in the absence of Lewis acids. The ionic liquids could be recycled and reused without loss of their catalytic activities.     

氯铝酸离子液体催化苯与1-己烯的烷基化反应

研究了在具有 Lewis酸性的氯铝酸离子液体体系中进行的苯与 1 -己烯的烷基化反应。以溴化 1 -乙基 - 3 -甲基咪唑 (emim Br) ,溴化 1 -丁基 - 3 -甲基咪唑 (bmim Br) ,盐酸三乙胺 (Et3NHCl) ,溴化四丁基铵 (C4 H9NBr) ,十六烷基三甲基溴化铵 (C19H4 2 Br N)分别与 Al Cl3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 ,反应转化率在短时间内达到1 0 0 %。其中 Et3NHCl- Al Cl3离子液体单烷基选择性达到 98.1 %。而且催化剂易于分离并能重复使用 ,反应转化率没有明显降低     

新型Br鴑sted-Lewis双酸性离子液体的合成及其催化松香二聚反应

以盐酸为B酸供体将N-甲基咪唑(mim)质子化得到Brønsted酸性离子液体mim•HCl,继续与Lewis酸供体FeCl3反应合成了一族Brønsted-Lewis双酸性离子液体氯化-1-氢-3-甲基咪唑氯铁酸盐(1-x)[mim•HCl]x[FeCl3],式中x为Lewis酸所占的摩尔分数。分别用吡啶和乙腈探针红外光谱表征和比较了其酸性,并将其应用于催化松香的二聚反应。所合成的一族双酸性离子液体中, (1-x)[mim•HCl]x[FeCl3](x=0.64)催化松香二聚反应时,二聚产物的软化点比空白样品提高了15 oC;其催化活性在重复利用5次后才开始下降。     

Synthesis of cyclic carbonate from vinyl cyclohexene oxide and CO2 using ionic liquids as catalysts

Synthesis of cyclic carbonate from 4-vinyl-1-cyclohexene-1,2-epoxide (VCHO) and carbon dioxide was investigated without using any solvent in the presence of ionic liquid as a catalyst. Ionic liquids based on 1-alkylmethylimidazolium salts of different alkyl groups (ethyl, butyl, hexyl, octyl) and different anions (Cl⁻, BF₄⁻, PF₆⁻) were used as catalysts. The conversion of VCHO was affected by the structure of the imidazolium salt ionic liquids; the ones with the cations of bulkier alkyl chain length and with more nucleophilic anion showed better reactivity. Reaction temperature, carbon dioxide pressure, and zinc halide cocatalyst enhanced the addition of CO₂ to VCHO. Semi-batch operation with continuous supply of carbon dioxide showed higher VCHO conversion than batch operation did.     

Brønsted Acidic Ionic Liquids Mediated Metallic Salts Catalytic System for the Chemical Fixation of Carbon Dioxide to Form Cyclic Carbonates

Abstract  

The catalysts of COOH- and SO₃H-functionalized ionic liquids mediated metallic salts had been developed for the coupling of carbon dioxide and epoxides to form cyclic carbonates under mild reaction conditions without using additional organic solvents. The effects of different ionic liquids, metallic salts, varying the molar ratio of ionic liquid to metallic salt and reaction conditions were examined. The excellent yield of cyclic carbonates and the high turnover frequencies (TOF) were obtained at the optimum reaction conditions. In addition, the catalytic system offered high stability and reusability.     

Acylation of salicylamide to 5-acetylsalicylamide using ionic liquids as dual catalyst and solvent

The Lewis acidic ionic liquids, 1-butyl-3-methylimidazolium chloroaluminate ([BMIM]Cl-nAlCl₃) and N-butylpyridinium chloroaluminate ([BPy]Cl-nAlCl₃), were used as both catalyst and solvent in Friedel–Crafts acylation of salicylamide with acetyl chloride to 5-acetylsalicylamide. The Lewis acidic ionic liquids, substituting for the conventional carcinogenic nitrobenzene solvent and anhydrous AlCl₃ catalyst, showed excellent catalytic activity in the acylation of salicylamide to 5-acetylsalicylamide. When [BMIM]Cl-2AlCl₃ was used as the catalyst, the yield of 5-acetylsalicylamide reached 81.3%. When [BPy]-2AlCl₃ was used as the catalyst, the maximum yield of 5-acetylsalicylamide was 89.2%. The content of AlCl₃ and the structure of the cations in the ionic liquids had synergistic effect on the acylation reaction.     

Alternating copolymerization of carbon dioxide and epoxide by dinuclear zinc Schiff base complex

The successful alternating copolymerization of carbon dioxide and cyclohexene oxide was achieved by using a dinuclear zinc Schiff base complex, without forming cyclic carbonate. A remarkable effect of Lewis basic additives on the yield and selectivity of the product was demonstrated. Among the examined Lewis bases, 1,4-dioxane was the best additive, where the copolymerization with the dinuclear zinc Schiff base complex – 1,4-dioxane system produced selectively the perfectly alternating copolymer in high yield.     

Catalytic applications of immobilized ionic liquids for synthesis of cyclic carbonates from carbon dioxide and epoxides

The catalytic applicability of ionic liquids immobilized on various support materials such as silica, polystyrene and biopolymers in the cycloaddition of carbon dioxide with epoxides is reviewed in this work. Comparisons of the catalytic efficiency of these various catalysts have been done from the aspect of turnover number and reusability. The studies revealed that ionic liquids or support materials possessing hydrogen bonding capable groups exhibited enhanced catalytic activity towards cyclic carbonate synthesis. Moreover, the increased quest towards environmentally benign materials has renewed the search for biocompatible materials as support for ionic liquids.     

离子液体催化丁醇与盐酸反应制备丁基氯

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst （ZnCl2）. The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluoborate （[BMIM][BF4]） and N-butyl-N-methylimidazolium chloride （[BMIM]Cl） as well as hydrochloric salts of N-methylimidazol （[HMIM]Cl）, pyridine （[HPy]Cl） and triethylamine （[HEt3N]Cl）. It is shown that the intrinsic catalytic performance of all organic ammonium salts except [HEt3N]Cl is slightly superior to ZnCl2, while the selectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.     

功能化酸性离子液体催化合成丙酸异戊酯

研究了功能化酸性离子液体催化合成丙酸异戊酯的反应,考察了不同离子液体、反应温度、反应时间、离子液体与反应物物质的量比及催化剂重复使用次数等因素的影响。以功能化酸性离子液体［(CH₂)₄SO₃HMIm］HSO₄为催化剂,在60 ℃、n（丙酸）∶n（异戊醇）∶n（离子液体）=5∶5∶1和反应时间2 h的条件下,异戊醇转化率99.43%,丙酸异戊酯选择性100%。催化剂循环使用5次,催化活性基本不变。     

Polystyrene‐Supported N‐Heterocyclic Carbene–Silver Complexes as Robust and Efficient Catalysts for the Reaction of Carbon Dioxide and Propargylic Alcohols

Three polystyrene‐supported N‐heterocyclic carbene–silver complexes [PS‐NHC‐Ag(I)] and a polystyrene‐supported N‐heterocyclic carbene–copper complex [PS‐NHC‐Cu(I)] catalyst were synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy, inductively coupled plasma‐atom emission spectrometer, thermogravimetric analysis and scanning electron micrographs. The catalytic activity of the supported catalysts was investigated for the reaction of propargylic alcohols and carbon dioxide. PS‐NHC‐Cu(I) showed no catalytic activity to the reaction, while PS‐NHC‐Ag(I) showed a considerable high activity and selectivity for the reaction, yielding the corresponding α‐alkylidene cyclic carbonates in high to excellent yields under mild conditions. Most importantly, the supported catalysts could be separated easily from the products and reused up to 15 times without loss of their high catalytic activity, showing excellent stability. The effect of various reaction parameters such as carbon dioxide pressure, temperature, time, and catalyst loading on the reaction was also investigated.     

氯铝酸盐离子液体催化转移烷基化反应研究

制备了阳离子分别为盐酸三乙胺、1-甲基-3-丁基咪唑和N-丁基吡啶的三种氯铝酸盐离子液体,并通过27AlNMR和吡啶及乙腈吸附的红外光谱等手段对其结构和酸性进行了表征,比较了上述三种离子液体催化2-甲基萘与1,2,4,5-四甲苯转移烷基化的反应性能。结果表明,阳离子结构不同的三种离子液体具有不同的催化性能,Et3NHCl-2AlCl3离子液体具有最高的催化反应活性和较高的2,6-二甲基萘选择性,在20℃下反应8h,2-甲基萘的转化率和2,6-二甲基萘选择性分别为36.8%和62.3%。