The alcoholysis of acetonitrile prompted by Brфnsted acidic ionic liquid [HSO_3-pmim]HSO_4

Br(?)nsted acidic ionic liquids based on imidazolium cation were employed as a series of environmentally benign catalysts and mediums in the alcoholysis of acetonitrile to synthesize ester.The results showed that Br(?)nsted acidic ionic liquid [HSO_3- pmim]HSO_4 was an efficient catalyst and medium for the alcoholysis of acetonitrile which could be recycled easily without obvious decline in catalytic activity,the highest yield could reach 85%.     

BrФnsted Acidic Ionic Liquids as Efficient Catalysts and Mediums for the Synthesis of Half-esters: Structure-catalytic Selectivity Relationship

BrФnsted acidic ionic liquids based on imidazolium cation were employed as efficient catalysts and mediums for the ring opening of phthalic anhydride to synthesize half-esters. Good yields, short reaction time and mild reaction condition were achieved. Lower acidity of ionic liquid resulted in higher catalytic selectivity in the synthesis of half-esters. The minimum-energy geometries of sulfonic acid-functionalized ionic liquids based on imidazolium cation revealed that their acidities and catalytic selectivity in the synthesis of half-esters were related to their structures.     

硅花园法合成硅酸铝质子酸

A series of aluminasilicate Br?nsted acid catalysts were synthesized with the “silica garden” method, and characterized with XRD, XPS and NH₃-TPD technique. Acid center concentration was measured using ionic ex-change method. The catalytic activities for cumene cracking of the silica garden Br?nsted acid catalysts were ob-served and compared to that of zeolite HY and traditional acidic aluminasilicate catalysts. It was found that the 6-coordinate and 4-coordinate aluminum atoms were in silica garden Br?nsted acid catalysts. There were two kinds of acid centers and a little of crystal in silica garden Br?nsted acid catalysts. And it was also found that the crystal increased the acidities of the catalysts. The catalytic activity and strong acid center concentration of the silica garden Br?nsted acid catalysts were between that of zeolite HY and traditional acidic aluminasilicate catalysts.     

Novel BrФnsted Acidic Ionic Liquid Based on a Cyclic Guanidinium Cation： a Green, Efficient, and Recyclable Dual Slovent-catalyst System for Fisher Esterification

A novel Brфnsted acidic ionic liquid(IL)based on the cyclic guanidinium cation has been synthesized.This IL,as a strong Brфnsted acid catalyst or solvent,shows high catalytic activity and biphsaic behavor in the esterifications of carboxylic acids and alcohols.The produced esters as a separate phase can be conveniently decanted out from the IL and the IL is recyclable without any loss of catalytic activity.     

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.     

3-甲基-1-磺酸咪唑硫酸氢盐催化剂用于四组分一锅法合成不对称聚羟基喹啉衍生物(英文)

3-Methyl-1-sulfonic acid imidazolium hydrogen sulfate has been used as an efficient, halogen-free,and reusable Brnsted acidic ionic liquid catalyst for the synthesis of ethyl-4-aryl/heteryl- hexahydro-trimehtyl-5-oxoquinoline-3-carboxylates via the one-pot condensation of dimedone with aryl/heteryl aldehydes, ethyl acetoacetate, and ammonium acetate under solvent-free conditions. This method has the advantage of being clean and simple, as well as providing the desired product in high yield over a short reaction time. Furthermore, the catalyst could be recycled and reused four times without any discernible reduction in activity.     

Brønsted酸性离子液体中电化学合成树枝状聚苯胺

BrФnsted acid ionic liquids were successfully applied to the electrochemical synthesis of polyaniline films on platinum electrode surfaces by using cyclic voltammetry. The scanning electron micrographs showed distinct changes in morphological structures. The films exhibited quite dense packing and good ordering of polymer dendrite as compared with those prepared using conventional hydrochloric acid, indicating that Bronsting acid ionic liquids might be promising alternatives to dual medium-dopants in the synthesis of conducting polymers.     

Preparation and Characterization of a Novel Benzimidazolium Bronsted Acid Ionic Liquid and Its Application in the Synthesis of Arylic Esters

A novel Brφnsted acid task specific ionic liquid 1-ethylbenzimidazolium tetrafluoroborate （[Hebim]BF4） with functional benzimidazolium cation was synthesized and characterized by ^1H NMR, IR, MS spectra and elemental analysis. This novel ionic liquid was successfully used as dual solvent-catalyst for the synthesis of arylic esters. Higher yields were obtained in the presence of [Hebim]BF4 in comparison with other imidazolium ionic liquids because of the good solubility of the aromatic alcohols and aromatic carboxylic acids in [Hebim]BF4. The product could be separated conveniently from the reaction system, and the ionic liquid could be easily reused after removal of water under vacuum. After 10 times reuse, the selectivity of the ester was still 100%.     

Enhancing the Deactivation Durability of Nano-sized HZSM-5 for Aromatization by Adjusting its Ratio of Lewis／BrФnsted Acid Sites

Ratio of Lewis/BrФnsted acid sites (C1/Cb) on the surface of nano-sized HZSM-5 was successfully manipulated by means of steaming and acid leaching. Significant enhancement of the deactivation durability of nano-sized HZSM-5 in the aromatization of fluid catalytic cracking (FCC) gasoline olefins seems to be closely related to the increase of Lewis/BrФnsted acid sites ratio.     

BrФnsted Acidic Ionic Liquids: Novel Efficient,Cost-effective and Reusable Solvent-catalysts for Ritter Reaction

Several Brnsted acidic ionic liquids(ILs) were synthesized and used as dual solvent-catalysts for the Ritter reaction of benzonitrile with tert-butanol. In particular, IL11([NSPTEA][OTF]) showed excellent catalytic activity for the Ritter reaction. In the presence of IL11, various nitriles and tertiary alcohols as well as secondary alcohols were converted smoothly to the corresponding amides in good to excellent yields. In addition, this cost-effective ionic liquid [NSPTEA][OTF] was easily separated from the reaction mixture by extraction with a small amount of water, and was recycled five times without any significant loss in activity.     

Synthesis of N-（α-Alkoxyalkyl）benzotriazoles Catalyzed by Acidic Ionic Liquid at Room Temperature

N-（α-Alkoxyalkyl）benzotriazoles were synthesized via the condensation of benzotriazole with various aldehydes and alcohols catalyzed by acidic ionic liquid [hmim]HSO4 at room temperature. The yield was up to 99%. This novel method was effective when triethoxymethane was utilized instead of alcohols. Moreover, acidic ionic liquid could be reused easily with no significant degradation of its catalytic activity.     

The hydrogen sulfate recognition properties of azo-salicylaldehyde schiff base receptors

Azo-salicylaldehyde Schiff base-typed receptors containing an acidic H-bond donor moiety were syn-thesized and characterized. The UV-Vis data indicate that these receptors could act as selective col-orimetric sensors for basic anions and acidic species hydrogen sulfate by different color changes in a water-containing medium. The experiment of Brφnsted acid-base reaction by adding the sodium hy-droxide or perchloric acid revealed that the mechanism of recognition of anions might be deprotona-tion/protonation of the OH fragments by interacting with different anions and that the deprotona-tion/protonation process is fully reversible. The deprotonation/protonation of the receptors is respon-sible for the dramatic color change.     

无溶剂条件下离子液体催化香豆素衍生物的绿色合成(英文)

Brnsted acidic ionic liquids, namely 2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium hydrogen sulfate, N-methyl-2-pyrrolidonium dihydrogen phosphate, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate, and triphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate, catalyzed efficient Pechmann condensation of phloroglucinol with β-keto ethyl/ methyl esters. 5,7-Dihydroxy-4-methylcoumarin and 5,7-dihydroxy-4-phenylcoumarin were prepared in good to excellent yields under mild, ambient, and solvent-free conditions. Pyrano[2,3-h] coumarins were then prepared by one-pot three-component reactions of 5,7-dihydroxy-4-subsituted coumarin, malononitrile, and aldehydes in the presence of catalytic amounts of Br nsted basic ionic liquids, namely 2-hydroxyethylammonium formate, 3-hydroxypropanaminium acetate, 1-butyl-3-methylimidazolium hydroxide, pyrrolidinium formate, and pyrrolidinium acetate, under thermal solvent-free conditions. The catalysts are environmentally benign and can be easily prepared, stored, and recovered without significant loss of activity.     

无溶剂条件下以N-甲基-2-吡咯烷酮硫酸氢盐为离子液体催化剂高效、环境友好一锅法合成1,5-苯二氮衍生物(英文)

A powerful and environmentally benign method has been developed for the one-pot synthesis of 4-substituted-1,5-benzodiazepines via the three-component reaction of a series of aldehydes with dimedone and o-phenylenediamine using [H-NMP][HSO_4] as a Brnsted acidic ionic liquid catalyst under solvent-free conditions. The key benefits of this new method over existing techniques include high yields, the use of a green catalyst, short reaction times and facile catalyst separation.     

Oxalic acid as a simple and efficient organocatalyst for three-component synthesis ofα-amino nitriles

A simple,efficient,and general method has been developed for the synthesis ofα-amino nitriles.Oxalic acid as a BrФnsted acid promotes the addition of TMSCN to various imines(generated in situ).     

1-Butyl-3-methylimidazolium Hydrogen Sulfate [bmim]HSO4: An Efficient Reusable Acidic Ionic Liquid for the Formylation of Alcohols

1-Butyl-3-methylimidazolium hydrogen sulfate [bmim]HSO4 as an acidic ionic liquid was prepared and used as a catalyst for the formylation of alcohols with ethyl formate at room temperature with good to excellent yields. A good selectivity was observed for the formylation of primary alcohols in the presence of tertiary alcohols.     

A novel ligand-free palladium catalytic system with SO3H-functional ionic liquids as cocatalyst for amidocarbonylation reaction

Effects of Lewis acid BF3·OEt2, and BrCnsted acids TsOH, CF3COOH, H3PO4, and HCIO4 as cocatalyst respectively on the ligand-free palladium-catalyzed amidocarbonylation were investigated. SO3H-functional ionic liquids 1-methyl-3-（4-sulfonic acid）butylimidazolium hydrosulfate [MIm（CH2）4803H][HSO4] and 1-methyl-3-（4-sulfonic acid）butylimidazolium triflate [MIm（CH2）4SO3H][OTf] were firstly employed as cocatalysts instead of these Lewis acid and Brφnsted acids. By using a ligand-free and weak corrosive catalyst in situ prepared form PdBr2, LiBr.H2O, and [MIm（CH2）4SO3H][OTf], the arnidocarbo- nylation of benzaldehyde, acetamide, and CO could proceed smoothly and afford N-acetyl-α-phenylglycine with yield of 58% in [C6mim]PF6 medium.     

新型磺酸功能化吡啶盐酸盐离子液体催化剂用于六氢喹啉合成(英文)

Sulfonic acid functionalized pyridinium chloride [pyridine-SO3 H]Cl has been synthesized as a novel Brnsted acidic ionic liquid and characterized on the basis of its FT-IR,1H and 13C NMR,MS,ther-mogravimetry,and derivative thermogravimetry data.The material has also been used as a highly efficient,homogeneous,and reusable catalyst for the preparation of hexahydroquinolines according to the one-pot multi-component condensation of arylaldehydes,dimedone(5,5-dimethylcyclohexane-1,3-dione),β-ketoesters,and ammonium acetate under solvent-free conditions.     

Brφnsted acidic ionic liquid catalyzed highly efficient synthesis of chromeno pyrimidinone derivatives and their antimicrobial activity

A series of 8,9-dihydro-2-(2-oxo-2H-chromen-3-yl)-5-aryl-3/f-chromeno[2,3-(flpyrimidine-4,6(5ff,7//)-diones(5a-j) have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4#-chromene-3-carbonitrile(4a-j) with couma-rin -3-catboxylic acid under neat conditions employing Br0nsted acidic ionic liquid(4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulfate as catalyst.Structures of all the compounds were established on the basis of analytical and spectroscopic data.All the compounds were evaluated for their in vitro antimicrobial activity against different bacterial and fungal strains.     

3-甲基-1-磺酸咪唑鎓硫酸氢存在下四组分一锅法合成苯并[g]茚并[2,1-b]喹啉衍生物(英文)

A simple and facile synthesis of 12-arylbenzo[g]indeno[2,1-b]quinoline-6,11,13-trione deriv-atives was accomplished by the one-pot condensation of 2-hydroxynaphthalene-1,4-dione, aryl aldehydes, 2H-indene-1,3-dione, and ammonium acetate under solvent-free conditions in the presence of a Brnsted ionic liquid catalyst, namely 3-methyl-1-sulfonic acid imidazolium hydrogen sulfate.