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( Neha Karanwal ),김재훈 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Lignocellulosic biomass is one of the most rational carbon supplies for producing valuable chemicals and fuels. Levulinic acid (LA) has appeared as one of the most promising renewable platform molecules. Several derivatives of LA have been investigated as cellulosic fuels or fuel additives; these include γ-valerolactone, 2-methyltetrahydrofuron, and valeric acid (VA) and its esters. VA has been considered as an excellent alternative biofuel candidate for conventional liquid transportation fuels and commodity chemicals. Herein, we developed a Nb promoted Cu/Zr-porous silica (Nb-Cu/ZPS) catalyst, which was found to be highly selective toward hydrodeoxygenation (HDO) of ketonic (> C=O) group in the LA to VA with a maximum yield of >95% under mild conditions (150 °C, 3 MPa H<sub>2</sub> and 2h) in an aqueous medium. The HDO performance of Nb-Cu/ZPS catalyst is found extraordinarily high as compared to previous reports on noble or non-noble metal-based catalyst.
김재훈,( Neha Karanwal ),( Deepak Verma ),( Malayil Gopalan Sibi ) 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Herein, we presented highly selective hydrogenation of ketonic (> C=O) group in levulinic acid (LA) into 1,4-pentanediol (1,4-PDO) over ZnO-promoted Cu-Ni-H-ZSM-5 catalyst under mild reaction conditions (120 °C, 2.5 MPa and 2 h) in an aqueous medium. The 1,4-PDO selectivity was up to 93.7%. The presence of intermetallic Cu-Ni, Cu-Zn and Ni-Zn sites in the catalyst, which was confirmed by HAADF-STEM analysis, was found to be highly active sites for the reactant conversion. Not only this, the change in acid density of the catalyst proximate to the metal sites accelerated the reaction in the forward direction; the weak Lewis acid sites increased upon increasing the metal content, while both the moderate and strong acid sites decreased. The catalyst could be efficiently recycled and reused through simple treatments, offering above 90% LA conversions and high-yield 1,4-PDO in consecutive reactions.
Insyani, Rizki,Verma, Deepak,Cahyadi, Handi Setiadi,Kim, Seung Min,Kim, Seok Ki,Karanwal, Neha,Kim, Jaehoon Elsevier 2019 Applied Catalysis B Vol.243 No.-
<P><B>Abstract</B></P> <P>Tandem heterogenous catalysis of bimetallic Cu-Pd on UiO-66(NH<SUB>2</SUB>) that were incorporated into sulfonated graphene oxide (Cu-Pd/UiO-66(NH<SUB>2</SUB>)@SGO or Cu-Pd/US) was investigated for the one-pot, direct conversion of di- and polysaccharides into 2,5-dimethylfuran (2,5-DMF) without separation of reaction intermediates. In the absence of a homogeneous acidic catalyst, consecutive reactions of glycosidic bond cleavage, isomerization, dehydration, and hydrogenation/hydrogenolysis were preceded by the synergistic effect of a multifunctional Cu-Pd/US catalyst. The strength and ratio of Brønsted and Lewis acid sites by adjusting UiO-66(NH<SUB>2</SUB>) to SGO ratios resulted in high-yield 5-(hydroxymethyl)furfural (5-HMF) through sequential glycosidic bond cleavage, isomerization, and dehydration of sucrose. Unlike monometallic Cu and Pd, bimetallic Cu-Pd promoted consecutive COH hydrogenolysis and CO hydrogenation of reaction intermediates, producing 2,5-DMF with a high yield of 73.4% during the one-pot conversion of sucrose at 200 °C and 1 MPa H<SUB>2</SUB> for 3 h. When starch was converted over Cu-Pd/US, 2,5-DMF was formed with 53.6% yield. Direct cellulose conversion into 2,5-DMF with a yield of 29.8% was achieved in the presence of 0.01 M HCl and Cu-Pd/US. The presence of the amino functional group (-NH<SUB>2</SUB>) in the UiO-66 framework was beneficial for improving the feed conversion and maintaining catalyst recyclability up to five times with almost no activity loss.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cascade reactions from di- and polysaccharides to 2,5-DMF over CuPd/UiO-66(NH<SUB>2</SUB>)@SGO. </LI> <LI> Control of Brønsted and Lewis acid sites by adjusting UiO-66(NH<SUB>2</SUB>) to SGO ratio. </LI> <LI> Cu-Pd selectively promoted COH hydrogenolysis and CO hydrogenation of 5-HMF. </LI> <LI> One-pot sucrose conversion to 73.4% yield 2,5-DMF without intermediate purification. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>