• 제목/요약/키워드: N,N-Dimethylformamide

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Bromolactonization of 2-Substituted-1-Cyclohexenyl-1-acetic acid (2-치환-1-Cyclohexenyl-1-acetic acid의 브롬락톤화 반응)

  • Jew, Sang-Sup
    • YAKHAK HOEJI
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    • v.33 no.3
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    • pp.206-210
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    • 1989
  • Bromolactonization of 2-Substituted-1-cyclohexenyl-1-acetic acid (1) with 1,3-dibromo-5,5-dimethylhydantoin (dibromantin) in N,N-dimethylformamide gave the corresponding ${\gamma}-bromo-{\beta}-lactone$ (2) and ${\beta}-bromo-{\gamma}-lactone$ (3). The effect of the substituents, the reaction temperature, and the solvent on the regioselectivity was discussed.

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Theoretical Mechanism Studies on the Enantioselectivity of aza-MBH-type Reaction of Nitroalkene to N-tosylimine Catalyzed by Thiourea-tertiary Amine

  • Lu, Nan;Wang, Huatian;Wang, Yangping
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3591-3596
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    • 2013
  • The enantioselective aza-Morita Baylis Hillman reaction of nitroalkene and N-tosylimine catalyzed by thiourea-tertiary amine has been investigated using density functional theory. Enantioselectivity is dominated by the cooperative effect of non-covalent and weak covalent interactions imposed by different units of catalyst. As Lewis base, the tertiary amine unit activates nitroalkene via weak covalent bond. The weak covalent interaction orients the reaction in a major path with smaller variations of this bond. The aromatic ring unit activates N-tosylimine via ${\pi}-{\pi}$ stacking. The non-covalent interaction selects the major path with smaller changes of the efficient packing areas. Thiourea unit donates more compact H-bonded network for species of the major path. The calculated ee value in xylene solution phase (97.6%) is much higher than that in N,N-Dimethylformamide (27.2%). Our conclusion is also supported by NBO analysis.

Basicity of Urea: Near-Infrared Spectroscopic and Theoretical Studies on the Hydrogen Bonding Ability of TMU and DMDPU

  • 이호진;최영상;박정희;윤창주
    • Bulletin of the Korean Chemical Society
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    • v.19 no.1
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    • pp.110-114
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    • 1998
  • The hydrogen-bonding interactions between thioacetamide (TA) and urea derivatives such as tetramethylurea (TMU) and dimethyldiphenylurea (DMDPU) have been studied using near-infrared absorption spectroscopy. Thermodynamic parameters for the interactions between TA and urea derivatives were determined by analyzing the $v^{as}_{N-H}$+Amide Ⅱ combination band of TA at 1970 nm. The ΔH° values, indicating the intrinsic strength of hydrogen bonding, are - 23.0 kJ/mole and - 19.8 kJ/mol for TMU and DMDPU, respectively. This is well explained by the inductive effects of substituents. Ab initio molecular orbital calculations for the proton affinity of TMU, N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA) in gas phase have been carried out at HF/3-21G ad HF/6-31G(d) levels, showing that the proton affinity of TMU is larger than that of DMA, which agrees well the experimental results.

Optically Active and Organosoluble Poly(amide-imide)s Derived from N,N'-(Pyromellitoyl)bis-L-histidine and Various Diamines: Synthesis and Characterization

  • Faghihi, Khalil;Shabanian, Meisam;Hajibeygi, Mohsen
    • Macromolecular Research
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    • v.17 no.11
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    • pp.912-918
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    • 2009
  • An optically active diacid containing the L-histidine moiety was prepared by reacting pyromellitic dianhydride (1,2,4,5-benzenetetracarboxylic acid 1,2,4,5-dianhydride) 1 with L-histidine 2 in acetic acid, and was polymerized with several aromatic diamines 5a-g to obtain a new series of optically active poly(amide-imide)s (PAIs) using two different methods, such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride ($CaCl_2$)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,N-dimethylformamide (DMF) system as a condensation agent. The resulting new polymers 6a-g with inherent viscosity was obtained in good yield. The polymers were readily soluble in polar organic solvents, such as N,N-dimethyacetamide (DMAc), N,N-dimethyformamide (DMF), and dimethyl sulfoxide (DMSO). The obtained polymers were characterized by FTIR, specific rotation, elemental analysis as well as $^1$H-NMR spectroscopy and gel permeation chromatography (GPC). The thermal stability of the resulting PAIs was evaluated with thermogravimetric analysis techniques under a nitrogen atmosphere.

Effect of Marangoni flow on Surface Roughness and Packing Density of Inkjet-printed Alumina Film by Modulating Ink Solvent Composition

  • Jang, Hun-Woo;Kim, Ji-Hoon;Kim, Hyo-Tae;Yoon, Young-Joon;Kim, Jong-Hee;Hwang, Hae-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.99-99
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    • 2009
  • Two different micro-flows during the evaporation of ink droplets were achieved by engineering both surface tension gradient and compositional gradient across the ink droplet: (1) Coffee-ring generating flow resulting from the outward flow inside the ink droplet & (2) Marangoni flow leading to the circulation flow inside the ink droplet. The surface tension gradient and the compositional gradient in the ink droplets were tailored by mixing two different solvents with difference surface tension and boiling point. In order to create the coffee-ring generating flow (outward flow), a single-solvent system using N,N-dimethylformamide with nano-sized spherical alumina particles was formulated, Marangoni flow (circulation flow) was created in the ink droplets by combining N,N-dimethylformamide and fotmamide with the spherical alumina powders as a co-solvent ink system. We have investigated the effect of these two different flows on the formation of ceramic films by inkjet printing method, The packing density of the ceramic films printed with two different ink systems (single- and co-solvent systems) and their surface roughness were characterized. The dielectric properties of these inkjet-printed ceramic films such as dielectric constant and dissipation factor were also studied in order to evaluate the feasibility of their application to the electronic ceramic package substrate.

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Preparation and Characterization of Microporous PVdF Membrane for Li-ion Rechargeable Battery (이차전지용 미세다공성 PVdF 분리막의 제조와 물성)

  • Nam, Sang-Yong;Yu, Dae-Hyun;Jeong, Mi-Ae;Rhim, Ji-Won;Byun, Hong-Sik;Jeong, Chul-Ho;Lee, Young-Moo;Seo, Myung-Su
    • Membrane Journal
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    • v.17 no.3
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    • pp.233-243
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    • 2007
  • In this study, a separate. which is a microporous membrane based on poly(vinylidene fluoride)(PVdF) was prepared by phase inversion method. Being prepared by dissolving the PVdF in the N,N'-dimethylformamide(DMF) with mechanical stirring, the homogenous casting solution was cast onto a clean glass plate. Pore size and porosity of the membranes were controlled by changing preparation condition. The highest porosity of the membrane was 78.6%. The mechanical property of the membrane was determined by using an universal testing machine(UTM). The morphology of the membrane was investigated by scanning electron microscopy(SEM). The cross-section of the membrane shows sponge-like small micro-pores.

A Study on the Emission Changes in Reduction Chemical Substances in Korea (유해화학물질 배출량 변화에 관한 연구: 배출저감계획서 작성 대상물질 중심으로)

  • Im, JiYoung;Lee, MyeongJi;Kim, HyunJi;Ryu, JiSung;Yun, DaeSik;Jang, YongChul;Lee, ChungSoo
    • Journal of Environmental Health Sciences
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    • v.46 no.2
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    • pp.159-169
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    • 2020
  • Objectives: The purpose of this study was to investigate changes among the nine kinds of reduction chemical substances in Korea over the period of 2008-2017. We will define basic data for improving the management methods for reducing chemical substances. Methods: A survey of hazardous pollutant emissions for 2008-2017 was conducted through the pollutant Release and Transfer Register homepage. Nine kinds of designated reduction chemical substances (Benzene, Vinyl chloride, Trichloro ethylene, 1,3-butadiene, Dichloro methane, Tetrachloro ethylene, N,N-dimethylformamide, Acrylo nitrile, and Chloroform) provided the study subjects. The emission of hazardous chemicals and health effects used the National Health Statistics and Integrated Chemicals Information System (ICIS) as a reference. Results: Hazardous pollutant emissions increased by 1.2 times over the past decade, and nine types of reduction chemical substances increased by 1.6 times. By region, the emissions of reduction chemical substances over the last 10 years were in the order of Chungbuk, Gyeonggi, and Gyeongbuk. Emissions of Dichloro methane was the highest in Chungbuk and Gyeongbuk. N,N-dimethylformamide was the highest in Gyeonggi. Carcinogen pollutant emissions showed a tendency to increase continuously. In addition, group 1 carcinogen emissions showed a tendency to decrease. Conclusion: In the last decade, the amount of hazardous chemical emissions has been continuously increasing. Hazardous chemical emissions require facility improvement for continuous emissions reduction. More research on reduction of emissions is needed.

Electrochemical Behaviour of (2,4-difluoro-phenyl)-(2-phenyl-1H-quinolin-4-ylidene)-amine in Aprotic Media (비양자성 매개물에서 (2, 4-difluoro-phenyl)-(2-phenyl-1H-quinolin-4-ylidene)-amine의 전기화학적 반응)

  • Kumari, Mamta;Sharma, D.K.
    • Journal of the Korean Chemical Society
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    • v.55 no.1
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    • pp.50-56
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    • 2011
  • The electrochemical reduction of (2,4-difluoro-phenyl)-(2-phenyl-1H-quinolin-4-ylidene)-amine was investigated in 0.1 M tetrabutylammoniumbromide in N,N-dimethylformamide at glassy carbon electrode (GCE) using the technique of cyclic voltammetry at the room temperature (290 K). The reduction of imines occurs in two successive steps, involving one electron in each. In this medium the first peak was observed at about -0.793 V (vs Ag/$Ag^+$) at the glassy carbon electrode surface, which is more stable and well defined as compared to the second peak. The diffusion coefficient ($D_0$) of imine in the investigated solvent media has been calculated using the modified Randles-Sevcik equation. The electron transfer coefficient ($\alpha$) of the reactant species has also been calculated.

Optimization of MOF-235 Synthesis by Analysis of Statistical Design of Experiment (통계학적 실험계획법 해석을 통한 MOF-235 합성 최적화)

  • Chung, Mingee;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.30 no.5
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    • pp.615-619
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    • 2019
  • Statistical design of experiments was performed to optimize MOF-235 synthesis process. Concentrations of terephthalic acid (TPA), iron (III) chloride hexahydrate, N,N-dimethylformamide (DMF) and ethanol were important factors to develop the crystal structure of MOF-235. MOF-235 was synthesized with various concentrations of the listed chemicals above and the crystallinity was measured by XRD. The effect of the composition on the synthesis of MOF-235 was evaluated using a statistical analysis. For the variance analysis using F-test, the concentration of ethanol showed the greatest effect on the crystallinity and TPA the least influential. A regression model for predicting the crystallinity of MOF-235 was derived and the prediction results for two synthetic variables were presented using contour plots. Finally, the crystallinity was predicted by a mixture method with $FeCl_3$, ethanol and DMF.

A Study of the Optimization of the MOF-5 Synthesis Process using Design of Experiments (실험계획법을 이용한 MOF-5 합성공정 최적화 연구)

  • Lee, Min Hyung;Lee, Sangmin;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.33 no.4
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    • pp.402-407
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    • 2022
  • Statistical design of experiments was used to optimize the MOF-5 synthesis process. A mixture design was employed to optimize precursor concentration. The optimal composition of three chemical materials, terephthalic acid, zinc acetate dihydrate, and N,N-dimethylformamide for MOF-5 synthesis was determined by extreme vertices design methods as follows; 1 mol : 2.7 mol : 40 mol. A multilevel factorial design was selected to screen the significance of synthesis reaction conditions such as temperature, time, and stirring speed. Statistical analysis results suggested excluding stirring speed from further investigation. Using a central composition design, the synthesis time and temperature were optimized. The quadratic model equation was derived from 13 synthesis experiments. The model predicted that MOF-5 synthesized at 119 ℃ for 10.4 h had the highest crystallinity.