Bronsted酸性离子液体催化酯化反应研究

合成了以2-吡咯烷酮和N-甲基咪唑为阳离子([Hnhp] [Hmim] ),HSO4-,H2PO4-和BF4-为阴离子的一系列Br(o)Pnsted酸性离子液体.考察了这些离子液体的热稳定性和酸性.以乙酸和异戊醇酯化合成乙酸异戊酯的反应考察了不同离子液体分别在不分水与分水条件下的催化效果,结果表明.不分水时,当醇/酸/[Hnhp]HSO4物质的量比为1.2∶1∶0.2,100℃下回流反应2 h,酯收率可达93.6%,反应结束后[Hnhp]HSO4体系可以顺利分相,[Hnhp]BF4则不能;分水时,[Hnhp]BF4可与酯自动分相,当醇/酸/[Hnhp]BF4物质的量比为1.2∶1∶0.01,120℃下回流反应1.5 h时,酯收率可达96.8%,比相同条件下[Hnhp]HSO4的略高.这两种体系中的离子液体均具有良好的重复使用性能.实验中还探讨了不同离子液体的酸性和催化酯化反应后与酯产物的分相效果对其催化活性的影响,结果表明,离子液体的酸性和与酯的不可混溶性对其在不同体系中酯化反应的催化活性有不同程度的影响.此外,在上述不分水酯化条件(醇∶酸∶催化剂物质的量比均为1.2∶1∶0.2,100℃油浴)下回流浸渍6 h比较离子液体[Hnhp]HSO4/BF4,[Hmim]HSO4/BF4和硫酸对奥氏体316不锈钢的腐蚀性,测得离子液体腐蚀率比硫酸低;除了[Hnhp]BF4,离子液体[Hnhp]HSO4,[Hmim]HSO4和[Hmim]BF4的腐蚀性呈现随酸性递减而下降的趋势.所测离子液体中[Hnhp]BF4腐蚀性最高.[Hnhp]BF4和硫酸中试样的腐蚀率分别为20.1和41.8g/(m2·h).     

离子液体催化合成对羟基苯甲酸乙酯

采用酸性离子液体[C3SO3 Hmim] HSO4、[C4SO3 Hmim] HSO4和[C3SO3 Hnhm] HSO4代替浓硫酸为催化剂合成对羟基苯甲酸乙醇.考察了反应温度、反应时间、催化剂用量、酸醇摩尔比对该反应产率的影响及离子液体的重复使用性能.选择了最佳反应条件,以[C3SO3 Hnhm] HSO4作为催化剂...     

Brönsted酸性离子液体催化酯化反应研究

合成了以2-吡咯烷酮和N-甲基咪唑为阳离子([Hnhp]＋和[Hmim]＋), , 和 为阴离子的一系列Brönsted酸性离子液体. 考察了这些离子液体的热稳定性和酸性. 以乙酸和异戊醇酯化合成乙酸异戊酯的反应考察了不同离子液体分别在不分水与分水条件下的催化效果, 结果表明, 不分水时, 当醇/酸/[Hnhp]HSO4物质的量比为1.2∶1∶0.2, 100 ℃下回流反应2 h, 酯收率可达93.6%, 反应结束后[Hnhp]HSO4体系可以顺利分相, [Hnhp]BF4则不能; 分水时, [Hnhp]BF4可与酯自动分相, 当醇/酸/[Hnhp]BF4物质的量比为1.2∶1∶0.01, 120 ℃下回流反应1.5 h时, 酯收率可达96.8%, 比相同条件下[Hnhp]HSO4的略高. 这两种体系中的离子液体均具有良好的重复使用性能. 实验中还探讨了不同离子液体的酸性和催化酯化反应后与酯产物的分相效果对其催化活性的影响, 结果表明, 离子液体的酸性和与酯的不可混溶性对其在不同体系中酯化反应的催化活性有不同程度的影响. 此外, 在上述不分水酯化条件(醇∶酸∶催化剂物质的量比均为1.2∶1∶0.2, 100 ℃油浴)下回流浸渍6 h比较离子液体[Hnhp]HSO4/BF4, [Hmim]HSO4/BF4和硫酸对奥氏体316不锈钢的腐蚀性, 测得离子液体腐蚀率比硫酸低; 除了[Hnhp]BF4, 离子液体[Hnhp]HSO4, [Hmim]HSO4和[Hmim]BF4的腐蚀性呈现随酸性递减而下降的趋势. 所测离子液体中[Hnhp]BF4腐蚀性最高. [Hnhp]BF4和硫酸中试样的腐蚀率分别为20.1和41.8 g/(m2•h).     

双磺酸基功能化多酸类离子液体的制备及其催化合成乙酸正丁酯

制备了四种多酸类离子液体,并应用于乙酸与正丁醇的酯化反应,发现双磺酸基功能化的多酸类离子液体[BS_2DABCD]HPW_(12)O_(40)呈现出最高的催化活性.研究了反应温度、催化剂用量、乙酸与正丁醇的物质的量的比和反应时间等因素对乙酸正丁酯产率的影响.在最佳反应条件下,乙酸正丁酯的产率达到82%.催化剂重复使用4次后,乙酸正丁酯的产率没有明显降低,显示出良好的重复利用性.     

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。     

酸性离子液体HSO4催化合成乙酸异戊酯

乙酸和异戊醇在酸性离子液体[Hmim]HSO4的催化下反应生成乙酸异戊酯。在优化的反应条件下离子液体用量2.5mL,异戊醇与乙酸的物质的量比为1:2.25,回流时间40min,收率可达到79%;催化剂可重复利用,易纯化,对环境无污染。     

Brønsted酸性离子液体中的二甘醇脱水环化反应

首次报道了Brønsted酸性离子液体介质中的二甘醇的脱水环化反应,考察了不同的离子液体、离子液体/二甘醇摩尔比、反应温度和时间对反应的影响。结果表明,Brønsted酸性离子液体作为反应介质能够促进脱水环化反应的有效进行,且在离子液体1-(3-磺酸根丙基)-3-甲基咪唑硫酸氢盐([SPmim]HSO4)中,二甘醇的转化率和1,4-二氧六环的选择性更高。采用Hammett指示剂法测定了离子液体的酸度函数H0,其酸性强弱顺序为[SPmim]HSO4 > [Bmim]HSO4 > [Amim]HSO4 > [Hmim]BF4> [Bmim]H2PO4 >[Amim]H2PO4 > [Hmim]Tsa,这与离子液体在脱水环化反应中的催化效果一致。当温度为170 ˚C,离子液体/二甘醇摩尔比为1:1时,二甘醇在[SPmim]HSO4中反应2 h,转化率可达到97.0%,1,4-二氧六环的选择性为89.3%。     

酸功能化离子液体催化合成聚缩醛二甲醚

对以酸功能化离子液体[Hnmp]HSO4、[Hnmp]H2PO4、[Hnmp]PTSA和[PyN(CH2)3SO3H]HSO4催化三聚甲醛和甲醇缩合制备聚缩醛二甲醚(PODEn,n1)的反应进行了研究,考察了催化剂用量、物料配比、温度和时间等对反应活性的影响。结果表明,离子液体的催化活性与其酸性相关。[PyN(CH2)3SO3H]HSO4具有较高的催化活性;当[PyN(CH2)3SO3H]HSO4的用量为2.0%、甲醇和三聚甲醛的物质的量比为2.0、反应温度110℃、反应压力2.0 MPa、反应时间6 h时,三聚甲醛的转化率和PODE3~8的选择性分别为97.69%和32.54%。反应结束后,[PyN(CH2)3SO3H]HSO4与产物可自动分成两相。     

酸性离子液体的合成和光谱表征

合成了基于N-甲基咪唑、2-吡咯烷酮阳离子的两个Br nsted酸性离子液体系列:[Hmim]HSO4/BF4、[Hnhp]HSO4/BF4以及两种—SO3H功能化酸性离子液体1-(3-磺酸基)丙基-3-甲基咪唑硫酸氢盐([C3SO3Hmim]HSO4)、N-(3-磺酸基)丙基吡咯烷酮硫酸氢盐([C4SO4Hnnp]HSO4)。其中,[Hnhp]HSO4/BF4,[C4SO4Hnnp]HSO4是本实验设计合成的新型酸性离子液体,而咪唑类离子液体用于对照。上述6种离子液体均以核磁共振、电喷雾质谱、红外光谱和紫外光谱分析法对结构加以表征并确认;并以它们作为溶剂和催化剂对乙酸、乙醇酯化反应进行初步试验,结果表明所合成的新型酸性离子液体(尤其是引入磺酸基的)是酯化反应较理想的绿色液体酸催化剂。     

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.     

Imidazolium ionic liquid-supported sulfonic acids: efficient and recyclable catalysts for esterification of benzoic acid

Several imidazolium ionic liquid（IL）-supported sulfonic acids with different anions,[C₃SO₃Hmim]HSO₄,[C₃SO₃Hmim]BF₄, [C₃SO₃ Hmim]PF₆,and[C₃SO₃Hmim]CF₃SO₃,were synthesized and applied as catalysts for esterification reaction of benzoic acid. The experimental results indicate that imidazolium IL-supported sulfonic acid containing anion of HSO₄^- shows the best catalytic activity.Only when less[C₃SO₃Hmim]HSO₄（0.3 equiv.） applied,was the product obtained with high yield of 97%.Furthermore, the produced esters could be separated by decantation,and the catalyst could be reused after the removal of water.     

BrΦnsted酸性离子液体掺杂聚苯胺的无溶剂制备及其表征

首先合成了两种带—SO3H官能团的Brφnsted酸离子液体([MIMPS][HSO4]和[PYPS][HSO4]),然后分别以这两种带—SO3H官能团的Brφnsted酸性离子液体做为掺杂剂,在无溶剂条件下通过机械化学聚合反应制备了掺杂导电态聚苯胺.由于带—SO3H官能团的Brφnsted酸性离子液体中H+可以单独以离子形式存在,因此可形成质子化导电态的翠绿亚胺盐,并以红外光谱、紫外可见-近红外、X-射线衍射、循环伏安和四探针技术等测试方法对聚苯胺进行了结构和性能表征.PANI-[MIMPS][HSO4]的结晶性、电导率和电化学活性要优于PANI-[PYPS][HSO4].     

Preparation of fructone catalyzed by water-soluble Brφnsted acid ionic liquids

Fructone(2-methyl-2-ethylacetoacetate-1,3-dioxolane),a flavouring material,has been synthesized from ethyl acetoacetate and glycol using five water-soluble Br(?)nsted acid ionic liquids as catalysts for the first time.The used Br(?)nsted acid ionic liquids include [Hmim]Tfa,[Hmim]Tsa,[Hmim]BF_4,[Bmim]HSO4,[Bmim]H_2PO_4,and[Hmim]BF_4 showed the highest catalytic activity for the preparation of fructone.After reaction,the product could be isolated from the reaction system automatically,and the ionic liquid could be directly reused without dehydration.     

Direct sulfonylation of Baylis-Hillman alcohols and diarylmethanols with TosMIC in ionic liquid-[Hmim]HSO4: an unexpected reaction

A Brønsted acidic ionic liquid-[Hmim]HSO₄ promoted unexpected reaction of Baylis-Hillman alcohols and diarylmethanols with p-toluenesulfonylmethyl isocyanide (TosMIC) affording the corresponding sulfone derivatives instead of N-tosylmethyl amides is reported. After isolation of the product, the ionic liquid [Hmim]HSO₄ was easily recycled for further use.     

Immobilization of HX：[Hmim]X as Halogenating Agent, Recyclable Catalyst and Medium for Conversion of Alcohols to Alkyl Halides

HX is immobilized by reaction of halogen acid with methylimidazole, and the formed ionic liquid [Hmim]X was used as halogenating agent, catalyst as well as medium for conversion of alcohols to alkyl halides. Excellent yields were obtained. The halides produced could be easily separated from the reaction mixture via simple decantation, and the ionic liquid [Hmim]X could be regenerated conveniently by adding equivalent of halogen acids followed by removal of water.     

Synthesis of terpinyl acetate using octadecylamine ethoxylate ionic liquids as catalysts

Terpinyl acetate, an important natural flavor, can be synthesized by esterification of α-pinene with acetic acid under acidic conditions. In this work, seven acidic ionic liquids were first synthesized, using octadecylamine ethoxylates (AC 1810, AC 1815, AC 1820, and AC 1830) as the cations, and characterized by FT-IR, ¹H NMR, and ¹³C NMR spectroscopy. The ionic liquids were then used as catalysts in the synthesis of terpinyl acetate. The effect of preparation conditions on catalyst performance was examined. It was found that the acidic ionic liquid 1-(3-sulfonic acid)propyl-3-poly(ethylene glycol) octadecylamine polyoxyethylene ether tetrafluoroborate ([PAC1815]⁺[BF₄]^?) was an excellent catalyst for synthesis of terpinyl acetate. The effects of the conditions used for preparation of terpinyl acetate were examined in detail, and the optimum preparation conditions were obtained. Under the optimum conditions, the yield of terpinyl acetate reached 35.70 %. When the catalyst was reused for the 5th time, the yield of terpinyl acetate was still 32.00 %. The results showed that effective separation and recycling of catalyst could contribute to developing a new strategy for synthesis of terpinyl acetate.     

Ionic liquid [Hmim]HSO4-promoted one-pot oxidative conjugate addition of sulfur-centred nucleophiles to Baylis-Hillman adducts

The first example of the one-pot oxidative conjugate addition of sulfur-centred nucleophiles to Baylis-Hillman adducts is reported. The reaction involves oxidation of Baylis-Hillman adducts with NaNO₃ in the Brønsted acidic ionic liquid [Hmim]HSO₄ to give [E]-α-cyanocinnamaldehydes followed by conjugate hydrothiocyanation/hydrosulfenylation with NH₄SCN/PhSH to afford the corresponding β-thiocyanato (or β-phenylsulfenyl)-α-cyanohydrocinnamaldehydes diastereoselectively in 76-89% yields in a one-pot procedure. After isolation of the product, the ionic liquid [Hmim]HSO₄ could be easily recycled for further use.