Mishra D.K.,Korea Institute of Industrial Technology |
Lee H.J.,Korea University |
Kim J.,Hanyang University |
Lee H.-S.,Korea Institute of Industrial Technology |
And 6 more authors.
Green Chemistry | Year: 2017
A new class of MnCo2O4 spinel supported Ru catalyst, Ru/MnCo2O4, was exploited to afford the highest yield of FDCA (99.1%) from base-free air-oxidation of HMF in water. The catalyst Ru/MnCo2O4 having both Lewis and Brønsted acidic active sites greatly enhanced the FDCA yield. The catalyst was recyclable up to five successive runs without considerable loss of its original activity. © 2017 The Royal Society of Chemistry.
Cho H.J.,Hanyang University |
Kim S.H.,Chemicals Randnter |
Hong S.W.,Hanyang University |
Yeo Y.-K.,Hanyang University
Fuel | Year: 2012
In this work, the single step method for non-catalytic esterification of palm fatty acid distillate (PFAD), which is readily applicable to actual production of biodiesel, was investigated. In this method, the esterification reaction is accomplished in a single step by ensuring water-free reaction conditions and the acid value is reduced to below 0.5 (mg KOH/g) which has not been possible in previous methods. The reaction was completed (<0.5 mg KOH/g) within 180 min at relatively high temperature (>250 °C) enough to be above boiling point of water and at moderate pressure (0.85-1.20 MPa) without any catalyst. The effects of temperature, methanol feed rate and pressure on a semi-batch reaction were investigated and the optimal values of these variables were found (temperature: 290 °C, pressure: 0.85 MPa, feed rate: 2.4 g/min). The acid value was reduced from 191.4 to 0.36 (mg KOH/g) just in 180 min at these conditions. From the kinetic study on non-catalytic esterification of PFAD, it was found that the activation energy is 17.74 kJ/mol and the frequency factor is 2.12 min -1. © 2011 Elsevier Ltd. All rights reserved.
Park Y.-K.,University of Seoul |
Kim S.J.,Kongju National University |
You N.,Kongju National University |
Cho J.,Kongju National University |
And 3 more authors.
Journal of Industrial and Engineering Chemistry | Year: 2011
The objective of the present study is to investigate the performance of MoO3/SiO2 as a catalyst for double bond migration from 2-butene to 1-butene. The effects of MoO3 addition on catalytic properties over SiO2 were analyzed through BET surface area, XRD, ammonia-temperature programmed desorption (NH3-TPD) and FT-IR of adsorbed pyridine. The highest activity of the 10% MoO3/SiO2 catalyst in double bond migration of 2-butene can be explained by the highest number of the weak acid sites. Based on the NH3 TPD and the FT-IR of pyridine adsorption results, the increase in the overall number of acid sites can be ascribed to an increase in the number of Lewis sites by the addition of MoO3. © 2011 The Korean Society of Industrial and Engineering Chemistry.
Lee S.,Dankook University |
Kim S.,Chemicals Randnter |
Hong I.-K.,Dankook University
Polymer (Korea) | Year: 2015
Characterization of a series of bio-based terpolymers containing various amounts of ethylene glycol, 1,4-cyclohexylene dimethanol, and isosorbide units were studied by 1H NMR and 13C NMR. The NMR results revealed that they had all random microstructures and that their sequence distribution was affected by the content of isosorbide. From DSC data for the terpolymer series investigated, it was observed that the glass transition temperature increased mainly as the content of isosorbide increased. The glass transition temperatures of terpolymers were estimated from the composition by extended Fox equation. © 2015 The Polymer Society of Korea. All rights reserved.
Lee H.,Purdue University |
Lee J.,Purdue University |
Park J.,Chemicals Randnter |
Kwon T.,Chemicals Randnter |
And 2 more authors.
Polymer Degradation and Stability | Year: 2015
Abstract Poly(propylene carbonate) (PPC) is a plastic material that can be mass produced from naturally abundant carbon dioxide. This polymer is also known to decompose back to CO2 when heated above about 200 °C. Here we report that the CO2-generation temperature of PPC can be reduced down to the 40-80 °C range in aqueous environment by using a photoacid generator (PAG) as the catalyst for activating the random scission reaction of PPC. We also investigated the thermal degradation of a PPC-based amphiphilic block copolymer, poly(poly(ethylene glycol) methyl ether methacrylate)-poly(propylene carbonate)-poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA-PPC-PPEGMA). These triblock copolymers form stable small-sized (<200 nm) micelles in water. We found evidence that with the aid of added PAG these micelles can degrade under mild heating conditions (<80 °C), similarly to what is expected from PPC homopolymer experiments. The combined results suggest that PPC-based amphiphilic block copolymers might be of interest for applications in ultrasound contrast. © 2015 Elsevier Ltd.