Catalytic Conversion of Glucose into Levulinic Acid Using 2-Phenyl-2-Imidazoline Based Ionic Liquid Catalyst.

Komal Kumar,Sreedevi Upadhyayula,Mukesh Kumar

doi:10.3390/molecules26020348

Komal Kumar, Sreedevi Upadhyayula + Show 1 more

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https://doi.org/10.3390/molecules26020348

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Abstract

Levulinic acid (LA) is an industrially important product that can be catalytically valorized into important value-added chemicals. In this study, hydrothermal conversion of glucose into levulinic acid was attempted using Brønsted acidic ionic liquid catalyst synthesized using 2-phenyl-2-imidazoline, and 2-phenyl-2-imidazoline-based ionic liquid catalyst used in this study was synthesized in the laboratory using different anions (NO3, H2PO4, and Cl) and characterized using 1H NMR, TGA, and FT-IR spectroscopic techniques. The activity trend of the Brønsted acidic ionic liquid catalysts synthesized in the laboratory was found in the following order: [C4SO3HPhim][Cl] > [C4SO3HPhim][NO3] > [C4SO3HPhim][H2PO4]. A maximum 63% yield of the levulinic acid was obtained with 98% glucose conversion at 180 °C and 3 h reaction time using [C4SO3HPhim][Cl] ionic liquid catalyst. The effect of different reaction conditions such as reaction time, temperature, ionic liquid catalyst structures, catalyst amount, and solvents on the LA yield were investigated. Reusability of [C4SO3HPhim][Cl] catalyst up to four cycles was observed. This study demonstrates the potential of the 2-phenyl-2-imidazoline-based ionic liquid for the conversion of glucose into the important platform chemical levulinic acid.

Highlights

Fossil fuel resources such as crude-oil, coal, and natural gas are currently used for liquid fuels and fulfill the demand for energy for the majority of the world population [1,2]
Lignocellulosic biomass derived from non-food crops and agricultural waste is a renewable and clean alternative energy source that can be catalytic converted into different types of commodity chemicals that can be used as fossil-fuel alternatives [8,9]
The [C4SO3HPhim][Cl] FT-IR spectrum displayed a broad peak at 3a3re00s–h3o6w0n0 icnmF−i1g, uwrehi1cah–cr.epTrheese[Cnt4sSOO3–HHPhsitmre]t[cChl]inFgT-oIRf tshpeecsturulfmondicispalcaiyded(–a broad SO3H) functionapleagkroaut p33i0n0–t3h6e00cactmal−y1s,t.wAhicphearekparepspeenatsreOd–Hin stthreetcrhainnggeoof fth2e81su0–lf3o0n2ic0accmid−1(–SO3H) which may be aftutnricbtiuotneadl gtorotuhpeiCn –thHe csatrtaeltycshti.nAgpveiabkraatpiopneasroedf tihnethaelirpahnagteicofb2u8t1y0l–c3h02a0incmat−-1 which tached to the immidaayzboeliantetrriibnugte[d40to]. tAheppCe–aHrasntrceetcohfinagstvriobnragtipoenaskofinthtehealripanhagteicobfu1t5y8l0c–h1a6in06attached cm−1 was attributotetdhetoimthideaCzo=lCinestrrientgch[4i0n]g

Summary

Introduction

Fossil fuel resources such as crude-oil, coal, and natural gas are currently used for liquid fuels and fulfill the demand for energy for the majority of the world population [1,2]. There is a need to explore clean and renewable energy alternative resources that can substitute these fossil fuels [4,5]. Lignocellulosic biomass derived from non-food crops and agricultural waste is a renewable and clean alternative energy source that can be catalytic converted into different types of commodity chemicals that can be used as fossil-fuel alternatives [8,9]. The use of the mineral acid catalyst in the production of LA poses some challenges such as separation, purification of LA, handling of the homogeneous acid catalyst and their high toxicity, and the generation of the acidic waste [25,26,27]

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