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Oxidation of 5-Hydroxymethyl-2-furaldehyde (HMF) using resin supported transition metals
( Huynh Thanh Thien Nhan ),조진구 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
5-Hydroxymethyl-2-furaldehyde (HMF), a product formed by the dehydration of certain sugars, is a versatile bio-based building block. Its molecular structure contains both aldehyde and alcohol functional group, which allows for various structural reformations into toxin-free and biodegradable furan-monomers. In this research, we focused on the oxidation of 5-Hydroxymethyl-2-furaldehyde (HMF) using transition metals deposited on ion exchange resin. Several metal catalysts and solvents were screened for the reaction. Results show that oxidation was achieved and HMF was completely converted to products such as 2,5-Furandicarboxaldehyde (DFF), 5-Formyl-2-furancarboxylic acid (FFCA), and 2,5 Furandicarboxylic acid (FDCA).
Direct synthesis of 2,5-dibutyl furandicarboxylates from galactaric acid
( Huynh Thanh Thien Nhan ),( Vanesa Teijeiro Seijas ),조진구 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
2,5-Furan dicarboxylic acid (FDCA) is considered one of the top 12 building block compounds derived from biomass that can lead to a sustainable development of a new chemical platform. In this research, a onepot synthesis of 2,5-dibutyl furandicarboxylates - a diester of FDCA - was studied. Due to differences in physical properties, 2,5-dibutyl furandicarboxylates are easier to manipulated than FDCA. This can be an advantage for later processes. The synthesis was conducted directly from galactaric acid, also known as mucic acid, with several catalysts and solvents. For the best reaction condition, a study of sufficient catalyst amount and kinetic changes of the main compounds was done. As a result, reaction mechanism and purification method for the interested products was proposed.
( Huynh Thanh Thien Nhan ),이경원,문다솜,박석규,조진구 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
2,5 Furandicarboxylic acid (FDCA) is considered one of the top 12 building block compounds derived from biomass that can lead to a sustainable development of a new chemical platform. FDCA has a potential as the replacement for terephthalic, isophthalic, and adipic acid, which are widely used components in the polymer industry. In this research, we focused on the homogeneous oxidation of 5-Hydroxymethyl-2-furaldehyde (HMF) using N-Hydroxyphthalimide (NHPI) or N-Hydroxysuccinimide (NHSI) together with metal co-catalyst. The desired product, FDCA, is achieved through 3 steps of oxidation as shown in the scheme below. Several metal co-catalysts and solvents were screened and optimized for the reaction. Results show that partial oxidation was achieved and the major product was 2,5-Furandicarboxaldehyde (DFF). New experimental conditions are being tested to further push the oxidation of DFF in order to achieve higher selectivity of FDCA.
Mental Health Among Healthcare Workers During the COVID-19 Pandemic in Vietnam
Nhan Phuc Thanh Nguyen,Ha Phan Ai Nguyen,Cao Khoa Dang,Minh Tri Phan,Huynh Ho Ngoc Quynh,Van Tuan Le,Chinh Van Dang,Tinh Huu Ho,Van Trong Phan,Van Trong Phan,Thang Phan,Dang Thi Anh Thu 대한예방의학회 2024 예방의학회지 Vol.57 No.1
Objectives: The objective of this study was to characterize mental health issues among Vietnamese healthcare workers (HCWs) and to identify related factors.Methods: A cross-sectional study was conducted with 990 HCWs in 2021. Their mental health status was measured using the Depression, Anxiety, and Stress Scale.Results: In total, 49.9%, 52.3%, and 29.8% of respondents were found to have depression, anxiety, and stress, respectively. The multivariable linear regression model revealed that factors associated with increased anxiety scores included depression scores (β, 0.45; 95% confidence interval [CI], 0.39 to 0.51) and stress scores (β, 0.46; 95% CI, 0.41 to 0.52). Factors associated with increased depression scores included being frontline HCWs (β, 0.57; 95% CI, 0.10 to 1.10), stress scores (β, 0.50; 95% CI, 0.45 to 0.56), and anxiety scores (β, 0.41; 95% CI, 0.36 to 0.47), while working experience was associated with reduced depression scores (β, -0.08; 95% CI, -0.16 to -0.01). Factors associated with increased stress scores included working experience (β, 0.08; 95% CI, 0.00 to 0.16), personal protective equipment interference with daily activities (β, 0.55; 95% CI, 0.07 to 1.00), depression scores (β, 0.54; 95% CI, 0.48 to 0.59), and anxiety scores (β, 0.45; 95% CI, 0.39 to 0.50), while age was associated with reduced stress scores (β, -0.12; 95% CI, -0.20 to -0.05).Conclusions: Specific interventions are necessary to enhance and promote the mental health of HCWs so they can successfully cope with the circumstances of the pandemic.
박석규,( Huynh Thanh Thien Nhan ),김보라,( Tanphat Nguyen ),( Vo Thi Hoang Anh ),이홍식,김상용,이관영,조진구 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
5-Hydroxymethyl-2-furfural (HMF) is the most well-known biomass-derived platform chemical, which has the possibility to replace BTX-based aromatic compounds produced from petroleum. 5-Chloromethyl-2-furfural (CMF) has been proved to be more efficient as material for later applications. In this study, the sythesis of 5-acetoxymethyl-2-furfural (AMF) from CMF and HMF using polymer resin supported alkylammonium acetates. HMF is formed by dehydration, which have used by continuous reactor from fructose, amberlyst-15, DMSO, 1,4-dioxane. CMF is produced by biphasic continuous reactor, which have formed easily from fructose, hydrochloric acid and dichloromethane or dichloroethane. The yield of AMF reached up to 60%.
Antonyraj, Churchil A.,Huynh, Nhan Thanh Thien,Park, Seok-Kyu,Shin, Seunghan,Kim, Yong Jin,Kim, Sangyong,Lee, Kwan-Young,Cho, Jin Ku Elsevier 2017 Applied Catalysis A Vol.547 No.-
<P><B>Abstract</B></P> <P>Au-Pd alloy nanoparticles supported on basic anion-exchange resin (AER) have exceptional catalytic activity for the oxidation of 5-hydroxymethyl-2-furfural (HMF) into 2,5-furan dicarboxylic acid (FDCA) with an equimolar amount of base. SEM-EDX and TEM analyses show that 5–20nm Au-Pd alloy nanoparticles are well dispersed both on the resin surface and inside resin spheres by a simple procedure without any assistance of additives. XPS analysis reveals that Au- and Pd metals exist in an alloy form on the AER support, which is confirmed by a comparison study with a mixture of AER-supported monometallic nanoparticles (AER-supported Au and AER-supported Pd). In the presence of a 1:1 ratio of Au-Pd alloy nanoparticles over Amberlite IRA-743 resin with O<SUB>2</SUB> (10bar) at 373K in an equimolar Na<SUB>2</SUB>CO<SUB>3</SUB> aqueous solution, HMF is oxidized to FDCA with a 93.2% yield. On the other hand, mixture of AER-supported Au and AER-supported Pd affords only a 52% FDCA yield under identical conditions. This catalyst can be used 6 times without any significant loss of activity. FDCA is also obtained from HMF with an 82.9% yield in air (40bar).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Au-Pd alloy nanoparticles were simply supported on basic anion-exchange resin. </LI> <LI> The nanoparticles were dispersed both on the resin surface and inside resin sphere. </LI> <LI> HMF was oxidized to FDCA with 93.2% yield using this catalyst. </LI> <LI> This catalyst could be used 6 times without any significant loss of activity. </LI> <LI> With this catalyst, FDCA was obtained from HMF with an 82.9% in air. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Basic anion-exchange resin (AER)-supported Au-Pd alloy nanoparticles were readily prepared and successfully applied to the oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furan dicarboxylic acid (FDCA).</P> <P>[DISPLAY OMISSION]</P>
Pham Hong Quang,유성초,Do Hong Minh,Huynh Thanh Nhan,Nguyen Huy Sinh 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
Substitution of Mn by Fe, Co, and Ni ions suppresses double exchange (DE), leading to a reduction in ferromagnetic interaction, or equivalently to lower values of Curie temperature, TC. The intensity of the electron paramagnetic resonance (EPR) line decreases exponentially with temperature, and the temperature dependence of EPR linewidth undergoes a minimum near TC. The activation energy values, Ea, derived from the temperature dependence of EPR line intensity, are equal to 0.074 eV, 0.093 eV and 0.086 eV for TM = Fe, Co, and Ni, respectively. In the case of cobalt substitution, an anomaly in the thermal evolution of the EPR linewidth has been observed. We attribute the cause of this anomaly to a Jahn-Teller transition or an electronic phase separation.