Polyethyleneimine (PEI), a potent architecture backbone was explored for the synthesis of novel polymeric ionic liquids (PolyE-ILs) with protagonist properties. The simple quaternization of PEI dendrimer with Bronsted acids (H 2 SO 4 , H 3 PO 4 , CH 3 SO 3 H, CF 3 COOH and TsOH) leads to formation of series of protic PolyE-ILs with corresponding counter anions [HSO 4 ] À , [H 2 PO 4 ] À , [CH 3 SO 3 ] À , [CF 3 COO] À and [TsO] À. The physicochemical properties of synthesized PolyE-ILs were studied by using TGA, Hammett acidity, hydrodynamic radii, solubility, and elemental analysis. PolyE-ILs showed characteristic Hammett acidity (0.94-1.78), good thermal stability (< 250°C) and enhanced hydrodynamic radii. However, use of PolyE-IL can be promoted for their wide applications as an acid catalysts. The reported PolyE-IL-1 with sulfonic acid counter ion was explored as catalyst for esterification of (E)-cinnamic acids and it showed good catalytic activity. The enhanced hydrodynamic radii due to the branched architecture of PEI dendrimers facilities the separation process via Nanofiltration (NF) membrane with no membrane fouling. Thus, PolyE-ILs can be highly active, easily recoverable, and reusable catalyst for esterification reactions with superior sustainability and economics. In addition to this the present one pot PolyE-IL synthesis process is non-complex and simple as compared to conventional post polymerization, ion exchange, and nucleophilic addition etc., strategies for synthesis of PILs.

Triethyl amine was successfully examined as a potent N-base surrogate for Knoevenagel condensation to produce cinnamic acids without compromising product yield.

Monophasic microwave assisted dehydration of fructose to 5-hydroxymethyl furfural (HMF) catalyzed by p-toluene sulphonic acid (PTSA) was studied in non-aqueous organic solvents.

Microwave‐assisted cyclodehydration of fructose to 5‐hydroxymethylfurfural (5‐HMF) was studied herein over polyvinyl alcohol (PVA)‐functionalized solid acid catalyst DICAT‐1 in low‐boiling green solvents. Of the tested solvent systems [isopropanol (IPA), tert‐butyl alcohol, THF, acetone, CH3CN, DMF, and DMSO], IPA was the preferred low boiling point (LBP) reaction medium, resulting in 95 % fructose conversion and 85 % 5‐HMF yield in 120 s. The characteristic dispersibility and swelling properties of DICAT‐1 in IPA had a significant effect on 5‐HMF yield. The catalyst DICAT‐1 was stable and robust under the reaction conditions and easily recycled. The structural and morphological characteristics of the catalyst were elucidated by FTIR spectroscopy, SEM/energy‐dispersive X‐ray spectroscopy, X‐ray fluorescence spectroscopy, XRD, and N2 sorption analysis. DICAT‐1 has covalently bonded −SO3H active sites, an amorphous nature, and mesoporous surface morphology; these features result in excellent performance in IPA. Estimated values of turnover number, turnover frequency, E‐factor, and process mass intensity categorize the overall process as environmentally safe for the production of 5‐HMF. A catalytic mechanism for 5‐HMF formation on DICAT‐1 is proposed.

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