A series of new carboxyl-functionalized benzimidazolium based ionic liquids (CFBILs) were synthesized and characterized by FT-IR, NMR and HR-MS (EI). Catalytic activities of CFBILs were evaluated towards the solvent free, one-pot synthesis of 1-amidoalkyl naphthol derivatives and found comparable to those of imidazolium based ionic liquids. Hammett values (H0) of the synthesized CFBILs have been determined using UV-vis spectroscopy and correlated with their catalytic activity. The catalytic activities were found to increase with the acidity of the CFBILs which reveal the formation of hydrogen bonding of CFBILs with aldehydes and this could play a crucial role to facilitate the product formation. The catalyst has shown excellent stability over wide range of temperature and good recyclability for several runs. © 2013 Elsevier B.V. All rights reserved.

Senthilkumar S

Department of Chemistry

School of Advanced Sciences

Vellore Campus

Pundlik Rambhau Bhagat

Muskawar P.N

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Molecular Catalysis A: Chemical

Owing to the importance of hydrogen peroxide (H2O2) in environment and biological systems, selective and sensitive detection of this key analyte has gained a large interest in the area of electroanalytical chemistry. Herein, we have synthesized highly water-insoluble phosphonium based carboxyl functionalized ionic liquid (TPP-HA[TFSI]) and characterized using various spectral techniques and single crystal X-ray diffraction. The synthesized TPP-HA[TFSI] was deposited over a multiwalled carbon nanotube (MWCNT) coated glassy carbon electrode (GCE). Thus obtained TPP-HA[TFSI]/MWCNT/GCE was used as a host matrix for the covalent immobilization of water soluble protein cytochrome c (Cyt c) through EDC/NHS coupling reaction to form a stable amide bond between free [sbnd]COOH groups of TPP-HA[TFSI] and -NH2 groups of Cyt c (Cyt c/TPP-HA[TFSI]/MWCNT/GCE). Electrochemical characterization of the fabricated electrode by cyclic voltammetry revealed distinct redox peaks corresponding to the heme active sites of Cyt c (FeIII/FeII) with a cathodic and anodic peak at −0.39 V and −0.27 V. Further, the modified electrode exhibited excellent performance towards electrochemical reduction of H2O2. A stable catalytic response was observed at an operating potential of −0.45 V using amperometry. The linear range, sensitivity and detection limit for the determination of H2O2 at Cyt c/TPP-HA[TFSI]/MWCNT/GCE were found to be 20 to 892 μM, 0.14 μA μM−1 cm−2 and 6.2 μM, respectively. Notably, the proposed modified electrode demonstrated excellent selectivity and sensitivity towards the determination of H2O2 along with remarkable stability and reproducibility. © 2019 Elsevier B.V.

Applied Surface Science

Electrochemical biosensor for the detection of hydrogen peroxide using cytochrome c covalently immobilized on carboxyl functionalized ionic liquid/multiwalled carbon nanotube hybrid

In this work, two Brønsted acidic ionic liquid (IL) catalysts containing benzimidazolium and imidazolium cation and two basic IL catalysts, i.e. 3-(2,3-dihydroxypropyl)1-methyl-1H-imidazole-3-ium hydroxide (DFImIL-OH−) and poly(3-benzyl-1-(4-(sec-butyl)benzyl)-1H-benzimidazole-3-iumhydroxide) (PIL(OH−), have been prepared. Developed catalyst was then characterized by NMR and FT-IR spectroscopy, and the acidity of BBAIL and ImBAIL was measured by the Hammett method using 4-nitroaniline as an indicator. Among all synthesized catalysts, benzimidazolium based Brønsted acid ionic liquid catalyst (BBAIL) was found to be best for the transesterification of castor oil in terms of biodiesel yield. Biodiesel yield was found to have affected significantly by castor oil to methanol molar ratio, reaction temperature and catalyst amount. Maximum yield of the biodiesel (i.e. 96%) was obtained using 1:12 M ratio of castor oil to methanol at 40 °C and 5 mol% of the catalyst loading in 14 h. Obtained results indicated that BBAIL could be an efficient catalyst for the synthesis of much-desired biodiesel synthesis. Major highlights of this work are moderate reaction temperature, easy catalyst separation and catalyst recyclability up to 3 cycles with little loss of yield. © 2018 Elsevier Ltd

Fuel

Transesterification of castor oil using benzimidazolium based Brønsted acid ionic liquid catalyst

The synthesis of polymer supported zinc–salen complex (PS-Zn–salen) is described. The mononuclear zinc(II)–salen complex was characterized by Fourier-transform NMR spectroscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrophotometry (FT-IR), thermogravimetric analysis, scanning electron microscopy, surface area and pore size distribution by Brunauer–Emmett–Teller. The synthesized PS-Zn–salen complex used as a recyclable heterogeneous catalyst for the efficient synthesis of hydantoins, thiohydantoins and Schiff bases in an aqueous medium. The isolated yields of hydantoins, thiohydantoins and Schiff bases achieved up to 89, 95 and 94%, respectively. In spite of conventional heterogeneous catalysts, current PS-Zn–salen complex shows thermal stability up to 280 °C. Moreover, the catalyst could be recovered easily by simple filtration and reused for next run with slightly declining its activity up to six successive runs. The FT-IR spectrum of recycle catalyst after 6th run confirmed that the catalyst was stable during the course of a reaction. The leaching of metal from the PS-Zn–salen is negligible, which was confirmed by AAS and hot filtration test. © 2017, Springer Science+Business Media B.V., part of Springer Nature.

Research on Chemical Intermediates

Facile access to polymer supported zinc–salen complex: highly efficient heterogeneous catalyst for synthesizing hydantoins, thiohydantoins and Schiff bases in aqueous medium

Abstract: Carboxyl-functionalized poly(ionic liquid) (CFPIL) was easily synthesized from its starting material and characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis and elemental analysis. The synthesized CFPIL was used as an efficient heterogeneous catalyst for the synthesis of β-amino ketones by three-component one-pot Mannich reaction between various aromatic aldehydes with amines and acetophenone at room temperature under solvent-free condition. The effect of the amount of catalyst and reaction time were investigated. The results showed that CFPIL has good to moderate catalytic activity and reusability. The catalytic process was simple and the catalyst could be easily recovered by filtration and washed with ethanol to reuse for the next experiment without significant loss of catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]. © 2017, Springer Science+Business Media B.V.

Solvent-free synthesis of β-amino ketones using carboxyl-functionalized poly(ionic liquid) at room temperature

Fulltext

Resource-Efficient Technologies

Deep-desulfurization of the petroleum diesel using the heterogeneous carboxyl functionalized poly-ionic liquid

Journal of Molecular Liquids

Aggregation behavior of COOH-functionalized imidazolium-based surface active ionic liquids in aqueous solution

Tetrahedron Letters

Influence of –SO3H functionalization (N-SO3H or N-R-SO3H, where R=alkyl/benzyl) on the activity of Brönsted acidic ionic liquids in the hydration reaction

Synthetic Communications

Zinc Benzenesulfonate–Promoted Eco-Friendly and Efficient Synthesis of 1-Amidoalkyl-2-naphthols

Silica gel supported –SO3H functionalised benzimidazolium based ionic liquid as a mild and effective catalyst for rapid synthesis of 1-amidoalkyl naphthols

RSC Advances

Ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate: a novel and highly efficient catalyst for the preparation of 1-carbamatoalkyl-2-naphthols and 1-amidoalkyl-2-naphthols

Carboxyl-functionalized ionic liquids based on Benzimidazolium cation: Study of Hammett values and catalytic activity towards one-pot synthesis of 1-amidoalkyl naphthols

Journal	Data powered by TypesetJournal of Molecular Catalysis A: Chemical
Publisher	Data powered by TypesetElsevier BV
ISSN	1381-1169
Open Access	0