http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Upare, P.P.,Lee, J.M.,Hwang, D.W.,Halligudi, S.B.,Hwang, Y.K.,Chang, J.S. Korean Society of Industrial and Engineering Chemi 2011 Journal of industrial and engineering chemistry Vol.17 No.2
Selective hydrogenation of biomass derived levulinic acid (LA) to γ-valerolactone (GVL) has been efficiently catalyzed by Ru, Pt and Pd noble metal supported on carbon under vapor phase in a continuous down flow fixed-bed reactor system. Among the catalysts, 5wt.% Ru/C gave GVL with 100% selectivity at 100% LA conversion up to 240h (10 days) without loss in its activity. The higher catalytic activity and product selectivity of 5wt.% Ru/C catalyst has been attributed to the higher dispersion of metallic Ru over carbon in nano-sizes compared to Pt and Pd catalysts.
Hydrogenation of Tetralin over Supported Ni and Ir Catalysts
Upare, Dipali P.,Song, Byung Jin,Lee, Chul Wee Hindawi Limited 2013 Journal of nanomaterials Vol.2013 No.-
<P>Selective hydrogenation and ring opening (SRO) of tetrahydronaphthalene (tetralin) was studied over nickel and iridium supported catalysts in the context of the removal of polynuclear aromatics from diesel fuel. The tetralin hydrogenation was carried out in a fixed-bed reactor at 270°C, using H2pressure of 30 bars, WHSV of 2.3 h<SUP>−1</SUP>, and H2/feed molar ratio of 40; the resultant products were analyzed by GC and GC-MS. The Ir/SiO2catalyst gave 85% of tetralin conversion and 75.1% of decalin products selectivity whereas Ni/SiO2catalyst showed an unprecedented high catalytic performance with 88.3% of tetralin conversion and 93% of decalin products selectivity. The catalysts were characterized by using different characterization techniques such as XRD, TPR, and HR-TEM to know the physicochemical properties as well as active sites in the catalysts.</P>
Catalytic selective ring opening of methylcyclopentane in the presence of CO<sub>2</sub>
Upare, D.P.,Lee, C.W. Elsevier Scientific Pub. Co 2014 Fuel processing technology Vol.126 No.-
Simple and highly efficient approach for the utilization of carbon dioxide (CO<SUB>2</SUB>) in selective ring opening (SRO) of methylcyclopentane (MCP) over 0.9wt.% Ir/USY catalyst is described. Ring opening products such as n-hexane, 2-MP and 3-MP were formed during the SRO of MCP in the presence of CO<SUB>2</SUB>. The influence of CO<SUB>2</SUB> pressure on the total conversion and ring opening (RO) product selectivity was examined, which highlights the great potential of CO<SUB>2</SUB> utilization in petroleum industry for SRO process.
Upare, P.,Yoon, J.,Hwang, D.,Lee, U. H.,Hwang, Y.,Hong, D. Y.,Kim, J.,Lee, J.,Kwak, S.,Shin, H. Royal Society of Chemistry 2016 Green chemistry Vol.18 No.22
<P>We present a continuous one-step reaction pathway for optically pure lactide under atmospheric conditions based on a novel SnO2-SiO2 nanocomposite catalyst. The new heterogeneous catalytic system gave a record high lactide yield of 94% with almost 100% enantioselectivity and long-term stability (>2500 h) from L-lactic acid.</P>
An integrated process for the production of 2,5-dihydroxymethylfuran and its polymer from fructose
Upare, Pravin P.,Hwang, Young Kyu,Hwang, Dong Won The Royal Society of Chemistry 2018 Green chemistry Vol.20 No.4
<P>We report for the first time an integrated process for the selective production of 2,5-dihydroxymethylfuran (DHMF) from fructose <I>via</I> a two-step reaction in 1-butanol (BuOH). Fructose was initially dehydrated to 5-hydroxymethylfurfural in >95% yield using Amberlyst-15, and the resulting solution was directly transformed into DHMF in >97% yield by liquid-phase hydrogenation over a Cu(50)-SiO2 nanocomposite. This nanocomposite catalyst was demonstrated to be highly stable, with no Cu leaching or catalyst deactivation observed. The obtained DHMF/BuOH mixture was then transformed successfully into poly(2,5-furandimethylene succinate) by reaction with succinic acid. Thus, from both environmental and industrial perspectives, this protocol is a novel and effective method for producing a biomass-derived polymer from fructose.</P>
Direct chemical conversion of xylan into furfural over sulfonated graphene oxide
Upare, Pravin P.,Hong, Do-Young,Kwak, Jaesung,Lee, Maeum,Chitale, Sachin K.,Chang, Jong-San,Hwang, Dong Won,Hwang, Young Kyu Elsevier 2019 CATALYSIS TODAY - Vol.324 No.-
<P><B>Abstract</B></P> <P>Graphene oxide (GO) grafted with –SO<SUB>3</SUB>H group giving a Brønsted acidic function was successfully applied for selective conversion of xylan to furfural (FA), which can be utilized as a platform chemical for a variety of value-added derivatives. The sulfonated graphene oxide (GO–SO<SUB>3</SUB>H) was, for the first time, found to be superior for the selective production of FA with 86% yield from xylan in water as a green solvent. GO–SO<SUB>3</SUB>H was successfully recycled after the reaction, and retained its catalytic activity without significant reduction. It is noteworthy that the Brønsted acid site acts as a key role in the production of furfural from xylan. Additionally, the presence of oxy-functional groups not only strengthen grafting of –SO<SUB>3</SUB>H with GO which probably prevented leaching into the reaction medium, but also helps to enhance the sorption capacity of substrate on GO-SO<SUB>3</SUB>H.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GO-SO<SUB>3</SUB>H was found to be greater for the production of furfural (87%) from xylan without undesired char formation. </LI> <LI> GO-SO<SUB>3</SUB>H was offered its reusability without significant loss in catalytic activity. </LI> <LI> Oxy-functional groups in GO-SO<SUB>3</SUB>H strengthen the -SO<SUB>3</SUB>H and helps to enhance the substrate sorption capacity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Upare, D.P.,Park, S.,Kim, M.S.,Jeon, Y.P.,Kim, J.,Lee, D.,Lee, J.,Chang, H.,Choi, S.,Choi, W.,Park, Y.K.,Lee, C.W. THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2017 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.46 No.-
<P>Cobalt promoted Mo/beta (Beta zeolite) catalysts were prepared with different metallic loadings (0.5-1.5) by a co-impregnation method. The catalytic activities of the synthesized catalysts were investigated for the selective hydrocracking of tetralin and pyrolysis fuel oil (PFO) into mono-aromatic hydrocarbons (MAH) such as benzene, toluene and xylene (BTX) in a fixed-bed reactor system. Prior to using the CoMo/beta catalyst for crude PFO hydrocracking, different reaction parameters (including metallic loading, temperature, H-2 pressure, and LHSV) were investigated for the hydrocracking of a model feed, tetralin, to determine the best conditions for maximum BTX yield. The CoMo(0.5)/beta catalyst with a Co/Mo ratio of 0.5 produced the highest MAH yield of 62.6% at 99.5% conversion of tetralin, continuously for 140 h of reaction time without any deactivation. Furthermore, the CoMo(0.5)/beta catalyst was found to be superior among the tested CoMo/beta catalysts for hydrocracking real feed PFO, and it produced a maximum MAH yield of 54.8% at 99.1% conversion of PFO. The synthesized catalysts were characterized using different characterization techniques, including BET, NH3-TPD, SEM-EDS and ICP, to evaluate their physiochemical properties and determine the active sites present in the catalysts. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>
Upare, P.P.,Jeong, M.G.,Hwang, Y.K.,Kim, D.H.,Kim, Y.D.,Hwang, D.W.,Lee, U.H.,Chang, J.S. Elsevier 2015 Applied Catalysis A Vol.491 No.-
Highly active, thermally stable nickel-promoted copper-silica nanocomposite catalysts were prepared via a deposition-precipitation method and used for hydrogenation of levulinic acid (LA) using formic acid (FA) as H<SUB>2</SUB> feeder. Ni(20)Cu(60)-SiO<SUB>2</SUB> (3:1 weight ratio of Cu to Ni, 80wt% metal content) showed better activity for vapor-phase formation of γ-valerolactone (GVL) from LA with FA as a hydrogen source. The catalyst selectively converts 99% of LA into 96% of GVL; the remaining 4% is angelica-lactone (AL). The effect of different concentrations of Ni promoted on Cu-silica and different LA to FA molar ratios on the catalyst activity affecting the hydrogen-free hydrogenation of LA was studied. The catalyst Ni(20)Cu(60)-SiO<SUB>2</SUB> exhibited long-term stability (200h) without loss in activity. Characterization using TEM, XPS, TPR, XRD and N<SUB>2</SUB>O titration was performed to find the most active phase for LA hydrogenation to GVL and the reason for the long-term stability. It was found that Ni-promoted well-dispersed metallic Cu species were the most active phases in hydrogenation, and the nanocomposite nature of the catalyst helped in providing long-term stability to the active phase.
Upare, P.P.,Lee, M.,Lee, S.K.,Yoon, J.W.,Bae, J.,Hwang, D.W.,Lee, U.H.,Chang, J.S.,Hwang, Y.K. Elsevier Science Publishers 2016 CATALYSIS TODAY - Vol.265 No.-
<P>Ruthenium nanoparticles supported on graphene oxide (GO) catalysts have been evaluated for bio-based levulinic acid (LA) hydrogenation to produce vapor-phase cyclic ethers in a fixed-bed reactor. It was found that using the GO supported Ru nanoparticles (Ru/GO) produced additional hydrogenation products cyclic ethers (54%) and gamma-valerolactone (GVL; 41%), while Ru on carbon (Ru/C) catalysts gave only GVL with 100% LA conversion. To improve the yield of cyclic ethers, an additional two-step hydrogenation of LA via GVL was successfully carried out. This provided GVL as a second feedstock from which the Ru/GO catalyst could produce cyclic ethers such as methyltetrahydrofuran (MTHF) and tetrahydrofuran (THF). Ru on GO catalysts showed a 92% selectivity of predominantly cyclic ethers, including a 77% selectivity of MTHF through two steps process. Such a remarkable enhancement in activity and selectivity of LA hydrogenation over Ru/GO can be attributed to the well-dispersion of Ru nanoparticles, as well as favorable interaction with GO in the presence of oxy-functional groups of GO. In order to evaluate the active sites on the catalyst, they were characterized using different characterization techniques such as Raman, XRD, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), temperature-programmed desorption of NH3 (TPD), electron microscopy (TEM and SEM) and H-2-chemisorption and N-2 adsorption. (C) 2015 Elsevier B.V. All rights reserved.</P>