CO2 was activated and used as a reactant for the preparation of cyclic carbonates and quinazoline-2,4­(1H,3H)-dione using functionalized basic nanocrystalline zeolite Nano-ZSM-5 as catalysts. Nano-ZSM-5 was treated with aqueous NH3 solution to prepare basic Nano-ZSM-5. The surface basicity of the basic Nano-ZSM-5 was systematically varied by the surface modification with various amines and basic ionic liquids. Powder X-ray diffraction, N2 adsorption–desorption, scanning/transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, 29Si and 13C cross polarized-magic angle spin NMR, elemental analysis, and temperature-programmed desorption techniques were used to characterize the materials. Kinetic (rate constant, activation energy) and thermodynamic parameters (change in enthalpy, free energy, and entropy) were calculated for the cycloaddition reaction of CO2 to epichlorohydrin and 2-aminobenzonitrile by varying the reaction parameters. Basic Nano-ZSM-5 functionalized with methylimidazolium hydroxide exhibited remarkable high activity and selectivity in the preparation of cyclic carbonates and quinazoline-2,4­(1H,3H)-dione. The catalyst was separated and recycled with no significant loss in the activity. In this study mesoporous zeolite was made basic and then the basic property of the nanocrystalline zeolite surface was systemically tuned using various functional amines and ionic liquids under one umbrella.

Selective catalytic oxidation of carbohydrate-derived 5-hydroxymethylfurfural, furfuryl alcohol, and various aromatic and aliphatic compounds to the corresponding aldehyde is a challenging task. The development of a sustainable heterogeneous catalyst is crucial in achieving high selectivity for the desired aldehyde, especially using O 2 or air. In this study, a RuO 2 -supported Mn 3 O 4 catalyst is reported for the selective oxidation reaction. Treatment of MnO 2 molecular sieves with RuCl 3 in aqueous formaldehyde solution gives a new type of RuO 2 -supported Mn 3 O 4 catalyst. Detailed catalyst characterization using powder X-ray diffraction, N 2 adsorption, scanning and transmission electron microscopes, diffuse reflectance UV–visible spectrometer, and X-ray photoelectron spectroscopy proves that the RuO 2 species are dispersed on the highly crystalline Mn 3 O 4 surface. This catalytic conversion process involves molecular oxygen or air (flow, 10 mL/min) as an oxidant. No external oxidizing reagent, additive, or cocatalyst is required to carry out this transformation. This oxidation protocol affords 2,5-diformylfuran, 2-formylfuran, and other aromatic and aliphatic aldehydes in good to excellent yield (70–99%). Moreover, the catalyst is easily recycled and reused without any loss in the catalytic activity.

Octahedral MnO 2 molecular sieve (OMS) was prepared using hydrothermal synthesis route in the absence and in the presence of urea. OMS was also prepared by solvent free method.Catalysts were characterized by the complementary combination of X-ray diffraction, N 2adsorption, scanning electron microscope, UV-visible spectroscopy, thermo gravimetric analysis, and NH 3 & CO 2 temperature programmed desorption techniques. Catalysts were investigated in the oxidation of benzyl alcohols, hydration of aromatic/heterocyclic nitrile and condensation reactions (Knoevenagel and Aldol). Furthermore, applicability of the catalyst was extended in one-pot tandem conversion of benzyl alcohol to 2-benzylidenemalononitrile, (E)-chalcone, and 2,3-dihydro-1,5-benzothiazepine. 2-Benzylidenemalononitrile and (E)-chalcone were prepared by two steps tandem reactions from benzyl alcohol, whereas 2,3-dihydro-1,5-benzothiazepine was prepared by three steps tandem reaction from benzyl alcohol. Recycling study show that no significant decrease in the catalytic activity was observed even after five recycles. To the best of our knowledge, this is the first report, which shows that OMS materials obtained using different synthesis methods exhibited significant difference in the catalytic activity in the above mentioned reactions. flask fitted with a condenser. Product was filtered, washed with deionised water, and dried at 120 C for 8-10 h. Material is designated as OMS-2 (Yield = 80%). Synthesis of OMS-2 by solvent free methodOMS-2 was prepared under solvent free condition by following the reported procedure. 33 In a typical synthesis, 2.37 g KMnO 4 (0.06 mol) and 5.51 g (0.09 mol) of Mn(Ac) 2 .4H 2 O were mixed and grounded in a mortar. The mixed powder was kept in a Teflon lined autoclave at 120C for 12 h. The resulting black product was thoroughly washed with deionised water to remove any ions which may remain in the product, and dried at 120C for 8-10 h. Material is designated as OMS-2-SF (Yield = 56 %). Hydrothermal synthesis of OMS-2 using urea 8 mmol of KMnO 4 (1.26 g) was dissolved in 20 mL of deionised water. 28 mmol urea (1.68 g) was added (in 15 minutes) to the solution and the reaction mixture was stirred for 30 minutes at ambient condition. After 30 min, resulting solution was added drop wise to a vigorously stirred mixture of MnSO 4 .H 2 O (10.5 mmol, 1.77 g in 6 mL water) and conc. HNO 3 (0.6 mL). The reaction mixture was refluxed for 24 h in a round bottom glass flask fitted with a condenser. Product was filtered, washed with deionised water, and dried at 120C for 8-10 h. OMS-2 material prepared with urea is designated as OMS-2-U (Yield = 99 %). Catalyst characterizations X-ray diffraction (XRD) patterns were recorded in the 2θ range of 5-80° with a scan speed of 2°/min on a PANalytical X'PERT PRO diffractometer using Cu Kα radiation (λ=0.1542 nm, 40 kV, 40 mA) and a proportional counter detector. Nitrogen adsorption measurements were performed at -200C by Quantachrome Instruments, Autosorb-IQ volumetric adsorption analyzer....

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