SO_3H-功能化离子液体催化4,4'-MDC合成反应

The synthesis of methylene diphenyl dimethylcarbamate (4,4′-MDC) from methyl N-phenyl carbonate (MPC) and formaldehyde (HCHO) was conducted in the presence of sulfonic acid-functionalized ionic liquids (ILs) as dual solvent-catalyst. The influences of the kind of anion in the ionic liquids, reaction conditions and the recycle of the ionic liquid on 4,4′-MDC synthesis reaction were investigated. In addition, the acid strength of ILs was determined by the Hammett method with UV-visible spectroscopy, and the acid strength-catalytic activity relationship was correlated. The activity estimation results showed that [HSO3-bmim]CF3SO3 was the optimal dual solvent-catalyst. Under the suitable reaction conditions of 70°C, 40 min, molar ratio of nMPC/nHCHO 10/1 and mass ratio of WILs/WMPC 4.5/1, the yield of 4,4′-MDC based on HCHO was 89.9 % and the selectivity of 4,4′-MDC with respect to MPC was 74.9%. Besides, [HSO3-bmim]CF3SO3 was reused four times after being purified and no significant loss in the catalytic activity was observed.     

Brφnsted酸功能化离子液体催化环己醇脱水制备环己烯

B rφnsted酸离子液体可催化烷基化、酯化、醚化、缩合、重排等反应,为了降低离子液体的成本及筛选新的离子液体催化剂,设计合成了B rφnsted酸功能化离子液体N,N,N-三甲基-N-磺丙基-硫酸氢铵(TMPSHSO4),其结构经IR,1HNMR,13CNMR和MS的确证。以TMPSHSO4作为催化剂,对环己醇脱水制备环己烯的反应进行了研究。最佳反应条件为m(催化剂)∶m(环己醇)=1∶50,反应时间2 h,反应温度170~180℃,产品收率达87.2%,GC/MS分析结果表明,产品质量分数达99.04%,产品选择性为99.3%,离子液体可以回收并重复使用,催化活性保持不变。     

Brφnsted酸性功能化双核离子液体制备及催化合成醋酸丁酯研究

采用两步法制备了功能化Brφnsted酸性双核咪唑离子液体催化剂,并用1H-NMR、FT-IR对催化剂的结构进行了表征,系统考察了其在醋酸与丁酯催化酯化高选择性地合成醋酸丁酯反应中的催化性能。结果表明,功能化Brφnsted酸性双核咪唑离子液体具有很好的催化活性,其催化活性与阴离子的种类有关,其中双-(3-甲基-1-咪唑)亚丁基双硫酸氢盐(MTEIMHS)的催化活性最好,在最佳催化剂用量为1.6%(wt),反应在90℃的温度下反应4 h,醋酸转化率可达到82%,且选择性接近99.9%。由此可见MTEIMHS双核离子液体有望成为一种有潜力的酯化催化剂。     

三乙胺离子液体用于催化衣康酸酯化反应研究

制备了多种Brφnsted酸性离子液体,分别将其作为催化剂用于衣康酸酯化反应,考察其催化性能与结构的关系.筛选对比表明三乙胺类离子液体具有较好的催化性能及重复使用性,由FT-IR、NMR对其进行了表征测定.以离子液体[HSO3-pTEA]pTSA为催化剂合成衣康酸二正丁酯,在重复使用7次后催化所得酸转化率为96.5%.优化工艺条件下得酸转化率为98.8%,酯收率为96.7%;以离子液体[HSO3-pTEA]HSO4为催化剂合成衣康酸二异辛酯,在重复使用7次后催化所得酸转化率为95.2%.优化工艺条件下得酸转化率为98.7%,酯收率为96.3%.     

具有羧酸官能团的功能性离子液体萃取分离钇的研究(英文)

A new kind of hydrophobic ionic liquids [1-alkyl-3-(1-carboxylpropyl)im][PF6] has been synthesized,and their extraction properties for Y(III) in the nitric acid medium was also investigated.The effects of extractant concentration,equilibrium pH of aqueous phase,salt concentration,temperature etc.were discussed.The results show that this kind of Task-Specific Ionic Liquid(TSIL) needs to be saponified before being used for the Y(III) ex-traction,and the extraction is acid dependent,and the extraction efficiency increases with the aqueous phase acidity decreasing.Furthermore,the loaded organic phase is easy to be stripped;more than 95% Y(III) could be stripped from the loaded organic phase when the stripping acidity is higher than 0.07 mol?L?1.The slope analysis technique is used to investigate the extraction mechanism,and a possible cation-exchange extraction mechanism is proposed in the present extraction system.     

不饱和脂肪酸甲酯的绿色催化环氧化研究

选用氧化钼/叔丁基过氧化氢/阴离子离子液体{MoO3/TBHP/[bmimPF6]}(I)和氧化钼/过氧化氢/阴离子离子液体{MoO3/H2O2/[bmimBF4]}(II)两种绿色催化体系,探索了反应时间、反应温度、氧化剂/不饱和双键摩尔比和催化剂/不饱和双键摩尔比4个因素对不饱和脂肪酸甲酯环氧化转化率的影响。研究表明,实验条件下催化体系Ⅰ比催化体系Ⅱ具有更高的活性,MoO3可重复使用3次。     

在双磺酸基官能化Brφnsted酸性离子液体/[bmim]Br中均相合成山梨醇类成核透明剂

以脂肪多胺四甲基乙二胺、五甲基二乙烯三胺、1,3-丙烷磺内酯为起始原料,经季铵化、酸化两步反应,合成了两种阳离子结构中具有双磺酸基官能团的Brφnsted酸功能化离子液体二(3-磺酸基)丁基四甲基乙二铵硫酸氢根盐、二(3-磺酸基)丁基五甲基乙二烯三铵硫酸氢根盐,离子液体的结构经红外光谱、核磁共振氢谱得到确认,以4-硝基苯胺为指示剂测定离子液体的Hammett酸函数,两种离子液体酸强度均高于硫酸。以合成的离子液体与1-丁基-3-甲基咪唑溴化物构成的二元离子液体体系为反应体系,应用于山梨醇与苯甲醛、对甲基苯甲醛、3,4-二甲基苯甲醛的缩合反应中,结果表明,当离子液体的摩尔分数为15%(以山梨醇计),n(山梨醇)∶n(醛)=1∶2.05,于70℃反应4 h时,反应即可在无溶剂均相反应条件下顺利完成,体系中加入水,目标化合物即可析出,分离产率77.6%⁸4.8%,产物熔距≤5℃,二元离子液体经旋蒸除水,乙醚洗涤、真空干燥后可循环使用,循环使用5次催化活性基本保持不变。     

固载化BrФnsted酸离子液体催化合成环状碳酸酯的研究

制备了一系列聚苯乙烯树脂(PS)固载的系列BrФnsted酸性离子液体,并对其结构进行了表征。考察了固载化离子液体在二氧化碳与环氧化合物环加成反应中的催化性能,并对其反应条件进行了优化。在固载化离子液体PS-羧基异丁基-咪唑溴盐(PS-HBIMBr)的催化作用下,在反应温度为120℃、反应压力2.0 MPa的优化条件下反应3 h,碳酸丙烯酯的收率高达92.7%,该催化剂对二氧化碳与环氧化合物环加成反应具有良好的重复使用性能。     

固载化Br(o)nsted酸离子液体催化合成环状碳酸酯的研究

制备了一系列聚苯乙烯树脂(PS)固载的系列Br(o)nsted酸性离子液体,并对其结构进行了表征.考察了固载化离子液体在二氧化碳与环氧化合物环加成反应中的催化性能,并对其反应条件进行了优化.在固载化离子液体PS-羧基异丁基-咪唑溴盐(PS-HBIMBr)的催化作用下,在反应温度为120℃、反应压力2.0 MPa的优化条件下反应3h,碳酸丙烯酯的收率高达92.7％,该催化剂对二氧化碳与环氧化合物环加成反应具有良好的重复使用性能.     

磺酸功能化咪唑类离子液体催化丁二酸与丁二醇预聚酯化的过程研究

采用咪唑、1,3-丙磺酸内酯、1,2-二溴乙烷、1,4-二溴丁烷和聚乙二醇-200等为原材料合成了四种功能性磺酸类咪唑离子液体,考察了这四种离子液体催化剂酯化合成丁二酸丁二醇酯的性能,研究了催化剂用量、醇酸摩尔比、反应时间等因素对酯化反应的影响,并与钛酸正丁酯及钛酸异丙酯催化剂进行对比,得出其较佳工艺条件为:使用双-(3-丙烷磺酸-1-亚丁基咪唑)磺酸功能化离子液体为催化剂,用量为丁二酸摩尔质量的0.40%,醇酸比为1.3:1,反应温度160℃,反应时间为2 h,酯化率最高达到94.2%.     

Synthesis of high molar mass poly(12-hydroxydodecanoic acid) in brønsted acid ionic liquids

An easy and fast direct polyesterification method using Brønsted acid ionic liquids (BAILs) as both reaction medium and catalyst was investigated. High molar mass polyesters of 12-hydroxydodecanoic acid (up to ) were obtained in good yields at atmospheric pressure and low temperature (90-130 °C) after 10-120 min reaction and without any added catalyst, reaction conditions that are much milder than conventional ones. Ionic liquids composed of an acidic cation bearing sulfonic acid groups and an acidic anion, such as 3-alkyl-1-(butyl-4-sulfonyl)imidazolium hydrogen sulfates, gave better results than ionic liquids containing only an acidic anion, such as 1-alkyl-3-methylimidazolium hydrogen sulfates. The 1/1 BAIL/12-hydroxydodecanoic acid molar ratio was found to yield polymers of the highest molar mass.     

从废弃油脂生物柴油中分离不饱和脂肪酸甲酯

以废弃油脂制生物柴油为原料,以95%醇为溶剂,采用尿素包合法提取不饱和脂肪酸甲酯,为生物柴油联产具有高附加值化工产品打下基础.重点考察了尿素用量、溶剂用量、包合时间和包合温度对不饱和脂肪酸甲酯分离效果的影响.结果表明,尿素包合法从生物柴油中分离不饱和脂肪酸甲酯的适宜工艺条件为:尿素,生物柴油质量比为1.4～1.7,溶剂/生物柴油质量比为4.6～6.0,包合温度为10℃,包合时间为18 h.在适宜条件下,不饱和脂肪酸甲酯含量可达93.5%,收率可达55.8%.     

Solvent-free synthesis of benzoic esters and benzyl esters in novel Brønsted acidic ionic liquids under microwave irradiation

Fischer esterifications of benzoic acid with a variety of alcohols and a variety of acids with benzyl alcohol could be promoted by four novel Brønsted acidic ionic liquids a–d that bear a benzyl on the imidazolium or pyridinium cation. The reactions were carried out smoothly without the need of added catalyst with good to excellent isolated yields (77–98.5%) under solvent-free microwave irradiation conditions in the presence of 50 mol% ionic liquids. These ionic liquids could be recovered easily and recycled three times without any significant loss in their catalytic activity.     

Diffusion coefficients of C18 unsaturated fatty acid methyl esters in supercritical carbon dioxide containing 10% mole fraction ethanol as modifier

To determine the molecular diffusion coefficients of C18 unsaturated fatty acid methyl esters in supercritical carbon dioxide (scCO₂) containing 10 mol% ethanol as a modifier, four methyl esters of C18 fatty acids, i.e., methyl oleate, methyl ricinoleate, methyl linoleate and methyl linolenate were selected as the typical solutes. The diffusion coefficients were measured at temperatures from 313.15 to 333.15 K and pressures from 15 to 27 MPa using the Taylor–Aris chromatographic peak broadening (CPB) technique. The influences of temperature, pressure, density and viscosity of the solvent mixture on the diffusion coefficients were examined. The results show that methyl oleate always diffuses faster than methyl ricinoleate at the same operating condition. Moreover, the D₁₂ values in ethanol-modified scCO₂ decrease with the increase of the number of C-C double bonds in C18-methyl ester, which is consistent with the trend reported in pure scCO₂. The diffusivity data are compared with the estimation of eleven predictive models. The modified Wilke–Chang equation is the best purely predictive model and the free volume model of Dymond with two adjustable parameter gives the least errors with average absolute deviations lower than 2.5%.     

A bulky phosphite-modified rhodium catalyst for the hydroformylation of unsaturated fatty acid esters

A series of hydroformylation experiments was performed with a high-grade and a technical-grade-derived methyl oleate (MO) and a rhodium catalyst modified by the bulky tris(2-tert-butyl-4-methylphenyl)phosphite. In the hydroformylation of pure methyl oleate, relatively high turnover numbers were obtained (400–500 mol/mol/h) under mild conditions (molar ratio MO/Rh=910, 80–100°C and 20 bar; CO/H₂=1:1, solvent toluene), leading to about 95% conversion in 3 h. Fast isomerization occurs under these conditions to produce the trans oleate. Trans oleate reacts more slowly than cis oleate. At temperatures below 50°C, isomerization does not occur. The use of technical-grade methyl oleate, containing 14% 9,12 diene, methyl linoleate (ML), results in lower reaction rates because dienes form stable π-allylic intermediates, which slowly undergo hydroformylation. More severe conditions were applied to obtain higher rates. The rate varied from 50 to 400 mol/mol/h, depending on conditions (molar ratio MO/Rh=910, T=50–120°C, P = 50–80 bar; CO/H₂=1:1–1:6, solvent, toluene). Several isomers of ML were formed during the reaction. Subsequent hydroformylation of these isomers results in a complicated mixture of products. The product mixture consists predominantly of methyl formylstearate, methyl formyloleate, methyl diformylstearate, and some yet unidentified side products. A comparison of the classic triphenylphosphine-modified catalyst and the bulky phosphite-modified catalyst has shown that the latter is several times more active.     

离子液体催化合成乙二醇双丙烯酸酯

使用酸性离子液体［Hnmp］HSO₄作为合成乙二醇双丙烯酸酯的催化剂,考察了原料配比、反应温度、反应时间、催化剂用量和带水剂用量对反应的影响,结果表明,当n(乙二醇)∶n(丙烯酸)=1.0∶2.2、反应温度为（120～125） ℃、反应时间60 min、催化剂用量为酸醇总物质的量的2.00%和带水剂甲苯用量20 mL的条件下, 酯化率达90.9%。     

Application of Brönsted acid ionic liquids as green catalyst in the synthesis of 2-propanol with reactive distillation

Five Br?nsted acidic ionic liquids (ILs) were prepared and characterized by FT-IR, 1H NMR and 13C NMR. Their cat-alytic activities for the synthesis of 2-propanol (IPOH) via transesterification of isopropyl acetate (IPAc) with methanol (MeOH) were investigated. Among al the tested ILs, [Ps-mim]HSO4 performed best and was used as catalyst for further studies. The reaction kinetics were carried out to correlate the parameters in a homogeneous second order kinetic model. It has been found that there is close agreement between the calculated and experi-mental values. The high-pressure batch reactive distillation experimental apparatus was set up in order to en-hance the conversion of IPAc. A high conversion of IPAc of 99.4%was obtained under the optimal reaction conditions. The catalyst [Ps-mim]HSO4 can be recycled easily by a rotary evaporator and reused without any fur-ther treatment. The catalyst had been repeatedly used for four times and no obvious changes in the structure of catalyst could be observed.     

Intensified and safe ozonolysis of fatty acid methyl esters in liquid CO2 in a continuous reactor

We demonstrate a continuous reactor for performing the ozonolysis of fatty acid methyl esters (FAMEs) using liquid CO₂ as solvent. The fast reaction kinetics allows the use of small‐volume reactors to completely convert the FAMEs, forming secondary ozonides as the primary products. The short residence times also help maximize the yields of the secondary ozonides by minimizing over‐oxidation and the formation of oligomeric products. The liquid CO₂ medium promotes safe reactor operation by providing an essential fraction of overall reactor cooling and by diluting the vapor phase organics. We also demonstrate a continuous stirred reactor for the safe thermal decomposition of the secondary ozonides to their corresponding acids and aldehydes. Using a lumped kinetic model for the thermal decomposition of the ozonolysis products, we estimate activation energy values of 108.6 ± 0.6 kJ mol^?1 for the decomposition of secondary ozonides and 122 ± 3 kJ mol^?1 for the decomposition of the undesired oligomeric species. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2819–2826, 2017     

Preparation of fatty acid methyl esters for gas-chromatographic analysis of lipids in biological materials

Theoretically, preparation of fatty acid methyl esters (FAMEs) deals with reversible chemical reactions in a complex system. Methodologically, there are numerous ways, generally characterized by the type of catalysts used and steps involved. Although there are more than a half dozen common catalysts, the majority fall into either acidic (HCl, H₂SO₄ and BF₃) or alkaline types (NaOCH₃, KOH and NaOH), with each having its own catalytic capability and application limitations. In terms of steps, many conventional methods, including those officially recognized, consist of drying, digestion, extraction, purification, alkaline hydrolysis, transmethylation/methylation and postreaction work-up. Although these methods are capable of providing reliable estimates if some precautions are taken, they are cumbersome, time-consuming and cost-inefficient. A new approach has been to transmethylate lipidsin situ. Due to its simplicity, high sensitivity, comparable reliability and capability to determine total fatty acids, the method of direct transmethylation is finding a unique place in lipid determination. Regardless of which method is used, quantitative methylation requires chemists to take precautions at every step involved, particularly during FAME formation and subsequent recovery steps. Evidently, there is an urgent need for more systematic studies, guided by the chemical principle of reactions involved and physicochemical properties of regents and end products, into factors affecting these steps. Hopefully, this will lead to an improved method, which measures lipid composition in biological materials not only with high accuracy but also with high efficiency and minimum costs.     

Geometrical isomerisation of double bonds in acid‐catalysed preparation of fatty acid methyl esters

Acid‐catalysed methylation is frequently applied for the preparation of fatty acid methyl esters used for gas chromatographic analysis of fatty acids. A series of artefacts were observed in hydrochloric acid‐catalysed direct methylation of herring (Clupea harengus L.) muscle. The artefacts were identified as trans isomers of eicosapentaenoic and docosahexaenoic acid, and their levels increased with reaction time. The isomers were not found after methylation of a lipid extract of the herring muscle, even after extreme reaction times. In general, the trans isomers are only observed after methylation of certain marine tissues, indicating catalytic activity in these samples. Based on these results, it is recommended that direct methylation procedures are thoroughly validated with each matrix type analysed, and that reaction times should not be longer than necessary to complete the methylation.