Doping effects of ZnO quantum dots on the sensitive and selective detection of acetylene for dissolved-gas analysis applications of transformer oil

Park, Min Sun,Lee, Jun Ho,Park, Yunji,Yoo, Ran,Park, Seungryol,Jung, Hwaebong,Kim, Wonkyung,Lee, Hyun-Sook,Lee, Wooyoung Elsevier 2019 Sensors and actuators. B, Chemical Vol.299 No.-

<P><B>Abstract</B></P> <P>We report on the doping effect on the sensing properties of ZnO quantum dots (QDs) for the detection of acetylene. We found that In-doped ZnO (IZO) QDs exhibited a better sensing performance to 10 ppm acetylene than undoped ZnO (ZO) QDs and Al-doped ZnO (AZO) QDs. The higher sensing response of IZO QDs can be attributed to a greater number of reactive sites for detecting acetylene, which is likely to originate from the increased number of oxygen vacancies, and the larger optical band gap and surface area of IZO. This is due to a higher valence dopant and a smaller particle size. The sensing properties of IZO QDs to 10 ppm acetylene was also found to be superior to previously reported acetylene sensors that are based on semiconducting metal oxides. Furthermore, we demonstrated that 10 ppm of acetylene can be selectively detected in air within ∼100 s using a recently developed miniaturized gas chromatography (GC) integrated with the IZO QDs sensor. In addition, we found that the device can detect the major fault gases of hydrogen and acetylene separately within ∼100 s. Our study demonstrates that the device can be utilized in the GC-based on-line dissolved gas analysis to detect small amounts of acetylene gas in transformer oil.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We report the doping effect on the sensing properties of ZnO quantum dots for acetylene. </LI> <LI> Doping of ZnO quantum dots modified oxygen vacancies and optical band gaps. </LI> <LI> In-doped ZnO quantum dots exhibited a better sensing performance to 10 ppm acetylene. </LI> <LI> 10 ppm acetylene could be selectively detected using a miniaturized gas chromatography. </LI> <LI> The device can detect the major fault gases of hydrogen and acetylene separately within ∼100 s. </LI> </UL> </P>

Microporous Magnesium and Manganese Formates for Acetylene Storage and Separation

Samsonenko , Denis ,G.,Kim, Hyunuk,Sun, Yinyong,Kim, Ghyung-Hwa,Lee, Heung-Soo,Kim, Kimoon WILEY-VCH Verlag 2007 Chemistry, an Asian journal Vol.2 No.4

<P>Acetylene sorption of microporous metal formates M(HCOO)<SUB>2</SUB> (M=Mg and Mn) was investigated. Measurements of acetylene sorption at 196, 275, and 298 K showed a Type I isotherm with quick saturation at low pressures, and 50–75 cm<SUP>3</SUP> g<SUP>−1</SUP> uptake at 1.0 atm. The single-crystal X-ray structure analysis of the acetylene-adsorbed metal formates revealed that acetylene molecules occupy two independent positions in the zigzag channels of the frameworks with a stoichiometry of M(HCOO)<SUB>2</SUB>⋅1/3C<SUB>2</SUB>H<SUB>2</SUB>, which is consistent with the gas sorption experiments. No specific interaction except van der Waals interactions between the adsorbed acetylene molecules and the walls of the frameworks was found. Sorption properties of other gases, including CO<SUB>2</SUB>, CH<SUB>4</SUB>, N<SUB>2</SUB>, O<SUB>2</SUB>, and H<SUB>2</SUB>, were also investigated. When the temperature was increased to 298 K, the amount of adsorbed acetylene was still above 60 cm<SUP>3</SUP> g<SUP>−1</SUP> for Mg(HCOO)<SUB>2</SUB> and 50 cm<SUP>3</SUP> g<SUP>−1</SUP> for Mn(HCOO)<SUB>2</SUB>, whereas the uptake of other gases decreased substantially. The microporous metal formates may thus be useful not only for the storage of acetylene but also its separation from other gases at room or slightly higher temperatures.</P> <B>Graphic Abstract</B> <P>Exclusive entry: Microporous magnesium and manganese formates show not only a high capacity for acetylene sorption but also remarkable selectivity over CO<SUB>2</SUB>, CH<SUB>4</SUB>, N<SUB>2</SUB>, O<SUB>2</SUB>, and H<SUB>2</SUB> at room temperature. The single-crystal X-ray structure analysis of the acetylene-adsorbed metal formates reveals two acetylene sorption sites. <img src='wiley_img/18614728-2007-2-4-ASIA200600390-content.gif' alt='wiley_img/18614728-2007-2-4-ASIA200600390-content'> </P>

A highly efficient catalyst for direct synthesis of methyl acrylate via methoxycarbonylation of acetylene

Cong-Ming Tang,Xin-Li Li,Gong-Ying Wang 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

A non-petroleum approach for the catalytic synthesis of methyl acrylate via methoxycarbonylation of acetylene with carbon monoxide and methanol as nucleophilic reagent has been studied under various conditions. Pd(OAc)2/2-PyPPh2/p-tsa was found to be a highly efficient catalytic system. The types of phosphorus ligands and their concentration was a determinative factor for catalytic activity. Mono-dentate phosphorus ligand such as triphenylphosphine has no activity while 2-(diphenylphosphino)pyridine with a mixed N-P bidentate structure has an excellent activity. Catalytic performance of acids depends on their acidic strength and coordinative property. Among all acidic promoters, p-toluenesulfonic acid displayed an excellent performance. Other parameters such as solvent polarity and initial pressure of carbon monoxide have also important influences on the hydroesterification of acetylene. It is beneficial for the reaction that the solvents have a high polarity. At low pressure of carbon monoxide, to high active palladium catalyst, the reaction easily proceeded. However, at high pressure of carbon monoxide, acetylene will transfer from solution to gas phase,resulting in lower conversion of acetylene. In addition, due to steric hindrance of alcohols, methanol has a highest activity in hydroesterification of acetylene in low carbon alcohols. Under the optimal reaction conditions, 99.5% of acetylene conversion and 99.7% of selectivity toward methyl acrylate as well as 2,502 h−1 TOF were achieved.

Acetylene-bridged D-A-D type small molecule comprising pyrene and diketopyrrolopyrrole for high efficiency organic solar cells

Mun, J.W.,Cho, I.,Lee, D.,Yoon, W.S.,Kwon, O.K.,Lee, C.,Park, S.Y. Elsevier Science 2013 Organic electronics Vol.14 No.9

To explore effects of acetylene-incorporation, acetylene-bridged D-A-D type small molecules ((HD/OD)-DPP-A-PY) using pyrene as a donor and diketopyrrolopyrrole as an acceptor were successfully synthesized and characterized. (HD/OD)-DPP-A-PY exhibited planar back-bone, conjugation extension, enhanced light absorption, and low HOMO energy level. Combined with the advanced properties, solution-processed OSCs based on a blend of HD-DPP-A-PY as a donor and [6,6]-phenyl-C<SUB>71</SUB>-butyric-acid-methyl-ester (PC<SUB>70</SUB>BM) as an acceptor exhibited PCEs as high as 3.15%.

Reactions of Acetyl Radical with Acetylene - A Computational Study

Tran, Tu Anh,Schiesser, Carl H. Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.3

Ab initio and DFT molecular orbital calculations predict that acetyl radical reacts with acetylene through interactions primarily involving the SOMO of the radical and the in-plane ${\pi}$-bond of acetylene. An energy barrier (${\Delta}E_1$) of 39.6 kJ $mol^{-1}$ is predicted for the preferred anti arrangement of reactants at the CCSD(T)/cc-pVDZ//BHandHLYP/cc-pVDZ level of theory. NBO analysis reveals additional interactions between the radical SOMO and the nearby C-H ${\sigma}$-bond in acetylene worth about 10% of the total transition state interaction energy. This type of orbital interaction has not previously been observed in radical addition reactions involving C-C ${\pi}$-bonds.

Aromatic Formation from Vinyl Radical and Acetylene. A Mechanistic Study

Natalia, Debby,Indarto, Antonius Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.2

The viability of acetylene addition in each step of aromatic formation initiated by vinyl radical and acetylene also with its competition with structure rearrangement is investigated by determining optimal geometries and barrier and reaction energies using quantum mechanical methods. In principle, the addition reaction has more difficult in term of free energy and enthalpy compared to geometry arrangement. Under combustion conditions, i.e. T = 1200 K, acetylene addition is unfavorable mechanism as the barrier energy values rise much higher than that of geometry arrangement. However, in longer chain hydrocarbon case, e.g. n-CxHx+1 where x ³ 8, C-C bond rotation is rather difficult and requires high energy to form a ring structure, elongation chain is preferable.

Aromatic Formation from Vinyl Radical and Acetylene. A Mechanistic Study

Debby Natalia,Antonius Indartoa* 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.2

The viability of acetylene addition in each step of aromatic formation initiated by vinyl radical and acetylene also with its competition with structure rearrangement is investigated by determining optimal geometries and barrier and reaction energies using quantum mechanical methods. In principle, the addition reaction has more difficult in term of free energy and enthalpy compared to geometry arrangement. Under combustion conditions, i.e. T = 1200 K, acetylene addition is unfavorable mechanism as the barrier energy values rise much higher than that of geometry arrangement. However, in longer chain hydrocarbon case, e.g. n-CxHx+1 where x ³ 8, C-C bond rotation is rather difficult and requires high energy to form a ring structure, elongation chain is preferable.

Reactions of Acetyl Radical with Acetylene – A Computational Study

Tu Anh Tran,Carl H. Schiesser 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.3

Ab initio and DFT molecular orbital calculations predict that acetyl radical reacts with acetylene through interactions primarily involving the SOMO of the radical and the in-plane p-bond of acetylene. An energy barrier (DE1‡) of 39.6 kJ mol‒1 is predicted for the preferred anti arrangement of reactants at the CCSD(T)/cc-pVDZ//BHandHLYP/cc-pVDZ level of theory. NBO analysis reveals additional interactions between the radical SOMO and the nearby C-H s-bond in acetylene worth about 10% of the total transition state interaction energy. This type of orbital interaction has not previously been observed in radical addition reactions involving C-C p-bonds.

내압방폭구조에서 수소-공기와 아세틸렌-공기 혼합가스의 폭발압력과 상대습도의 상관관계 분석

김용태,정기효 대한안전경영과학회 2022 대한안전경영과학회지 Vol.24 No.4

To test a flameproof enclosure for the safety certificate, a reference pressure of explosion needs to be determined. However, the explosion pressure may be changed according to relative humidity of explosive gases. Therefore, the guideline on relative humidity should be recommended for measuring the explosion pressure for accurate and reproducible testings. This study examined the relationship of explosion pressure with relative humidity of hydrogen (31 vol %)-air and acetylene (14 vol %)-air mixture gases. The explosion pressures were measured by increasing the relative humidity of the gases by 10 % from dry state to 80 % in a cylindrical explosion enclosure of 2.3 L. on ambient temperature and atmospheric pressure (1 atm). The maximum explosive pressures were remained almost constant until the relative humidity reached 10 % for the hydrogen-air mixture and 20 % for the acetylene-air mixture. However, the maximum explosive pressures linearly decreased as the relative humidity increased. Based on the results of the study, it would be recommended to use 10 % relative humidity for the hydrogen-air mixture and 20 % for the acetylene-air mixture as the critical value in testing a flameproof enclosure.

Effects of hierarchical zeolites on aromatization of acetylene

Lee, Wonsuk,Lee, Taehee,Jang, Hoi-Gu,Cho, Sung June,Choi, Jungkyu,Ha, Kyoung-Su Elsevier 2018 CATALYSIS TODAY - Vol.303 No.-

<P><B>Abstract</B></P> <P>The conventional zeolites and the hierarchical zeolites were employed to investigate the catalytic performance of aromatization from acetylene. In the case of the conventional MCM-22 zeolites, the effects of their Si/Al ratio on the catalytic performance were investigated by considering the conversion of acetylene, the selectivity of aromatics, and the formation of cokes. By swelling the interlayers in the MCM-22 precursor followed by pillaring the swollen spaces, hierarchical zeolites with layered nanosheets (i.e., MCM-36) were successfully prepared, characterized and tested for aromatization. With the novel hierarchical zeolite-based catalysts, the effects of structural difference as well as the Si/Al ratio were scrutinized. From the catalytic activity tests, the selectivity towards aromatic compounds through MCM-36 was significantly improved, and the amount of carbon deposition was decreased a lot, probably due to the increased number of external Brønsted acid sites. To draw such conclusion, several characterization techniques were also applied and the results were analyzed. The techniques included physisorption, XRD, FT-IR, TEM, SEM, EDX methods.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MCM-22 and MCM-36 zeolites are characterized. </LI> <LI> Effects of Si/Al ratio and hierarchical structure on aromatization are investigated. </LI> <LI> A correlation between external Brønsted acid sites and BTX selectivity is revealed. </LI> <LI> Exposure of acid sites and mesoporosity lead to higher selectivity and lower coke. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>