• Bulletin of the Korean Chemical Society
• /
• 제29권7호
• /
• pp.1332-1334
• /
• 2008

Stable crystalline 1-Benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane tribromide (BABOT), can be readily synthesized from the reaction of the corresponding bromide with $HNO_3$ and aqueous KBr. Selective Oxidation of a variety of dialkyl and alkyl Aryl sulfides to the corresponding sulfoxides in high yield was achieved by this reagent in solution ($CH_3CN/H_2O$) and solvent free conditions. The reaction proceeds under neutral and mild conditions and can be carried out easily at room temperature with regeneration of BABOT. In this method purification of products is straightforward and no over oxidation to sulfone was noted.

• Bulletin of the Korean Chemical Society
• /
• 제15권6호
• /
• pp.465-468
• /
• 1994

The charge transfer compounds $(TTF)_4FeCl_3{\cdot}CH_3OH,\;(TTF)_4SbCl_4\;and\;(TTF)_5(SbBr_4)_2{\cdot}CH_3COCH_3$ were prepared from reactions of the TTF (tetrathiafulvalene) and metal halides. The compounds were characterized by spectroscopic (UV,IR, EPR and XPS) methods, magnetic susceptibility and electrical conductivity measurements. The d.c electrical conductivities of the pressed pellets are in the order of $10^{-1}-10^{-3} Scm^{-1}$, which lies in the range of semiconductor region at room temperature. It means that the partially ionized TTF has stacked in low-dimensional chain in each compound. Spectroscopic properties also indicate that TTF molecules are partially ionized and charge transfer has occurred from (TTF)n to Fe(III) center in $(TTF)_4FeCl_3{\cdot}CH_3OH$ whereas to the $-SbX_4^-$ entity in $(TTF)_4SbCl_4\;and\;(TTF)_5(SbBr_4)_2{\cdot}CH_3COCH_3$. The EPR g values are consistent with TTF radical formation and EPR linewidths suggest the delocalization of unpaired electrons along TTF stacks. A signal arised from metal (Fe and Sb) ions were not detected in EPR spectra, indicating that metal ion is in the diamagnetic state in each compound. The diamagnetic state was also examined by the magnetic susceptibility measurement. The magnetic properties reveal the significant interaction between the $TTF^+$ radical cations in the stacks. The oxidation state of metal ions was also investigated by XPS spectra.

• 대한화학회지
• /
• 제44권4호
• /
• pp.311-315
• /
• 2000

The Fe(II)-isothiocyanato complex $trans-[FeH(NCS)(dppe)_2]$ (1) eactedwith iodomethane(Mel) to give methyl isothiocyanide-Fe(n) complex, $trans-FeH(NCS(Me)-S)(dppe)_2]I(2)$. Compound 2 was oxidized to $trans-[Fe(NCS)_2(Ph_2P(O)CH_2CH_2P(O)Ph_2)_2][I_3]$ (3), which was structurally characterized by X-ray diffraction. The molecular structure of 3 showed a bent Fe-NCS group, Crystallographic data for 3: triclinic space group P1,a=11.071(2) A,b=12.054(2)A,c=12.121(1)A, $\alpha=101.02(1){\circ}C{\beta}=95.887(9){\circ}Cr=110.34(1){\circ}C$, $Z=1R(wR_2)=0.0567(0.1294)$.

• 대한화학회지
• /
• 제33권6호
• /
• pp.633-643
• /
• 1989

두 개의 아닐린계 질소와 두 개의 피리딘계 질소가 각각의 로듐이온에 트란스형으로 결합된 $Rh_2(ap)_4$(2,2-trans) 이성질체는 -0.40 V vs SCE에서 디 옥시젼의 한 전자를 환원시킬 수 있음을 보여주고 있다. 123K에서의 ESR 스펙트럼에 의하면 한 로듐이온에 산소 1분자가 측쇄 결합하여 $[Rh_2(ap)_4(O_2)]^-$이온을 형성하고, 착물은 $Rh_2^{III}$ 산화수를 가짐을 알 수 있다. 이 착물은 시안화메틸/염화메틸렌 혼합용액에서 Rh-$O_2^-$결합의 분열없이 [$Rh_2(ap)_4(O_2)(CH_3CN)]^-$을 형성한다. -0.25, 0.55V에서 산화되었을 때 [$Rh_2(ap)_4(O_2)]^-$ 은 $Rh_2(ap)_4(O_2)$와 [$Rh_2(ap)_4(O_2)]^+$을 형성하기 위하여 두 단계의 한 전자 산화과정이 일어난다. 두 화학종은 모두 초산소가 측쇄 결합되어 있지만, 전자는 $Rh^{II}Rh^{III}$, 후자는 $Rh_2^{III}$의 산화수를 갖는다. 반면에, ESR 스펙트럼과 $CH_3CN$ 부가 연구에서 보면 후자 착물이 로듐이온에 위치한 부대전자와 함께 [$Rh^{II}Rh^{III}(ap)_4(O_2)]^+$로 기술되고 그 착물은 측쇄 배위결합된 산소분자를 가지고 있음을 보여주고 있다. 또한 전기화학적, ESR 연구는 디 옥시젼의 활동도가 전기화학적 산화환원전위와 관계 있음을 보여주고 있다.

• 한국대기환경학회지
• /
• 제20권4호
• /
• pp.515-521
• /
• 2004

The catalytic oxidation of volatile organic compounds (methanol. acetaldehyde) has been characterized using the copper phthalocyanine catalyst in a fixed bed flow reactor under atmospheric pressure. The catalytic activity for pretreatment conditions was examined by this reaction system. The catalytic activity was ordered as follows: metal free-PC＜Cu ($\alpha$)-PC＜Cu ($\beta$)-PC The formaldehyde, carbon monoxide as a partial oxidation product of methanol and acetaldehyde over Cu ($\alpha$)-PC catalyst were detected and the conversions of methanol and acetaldehyde were accomplished above 95% over Cu ($\alpha$) -PC, Cu ($\beta$) - PC catalyst at 35$0^{\circ}C$. The pretreated metal free -PC, Cu($\alpha$)-PC, Cu($\beta$)-PC catalysts have been characterised by TGA, EA and XRD analysis. The catalytic activity pretreated with air and $CH_3$OH mixture (P-4) or air only (P-5) was very excellent. XRD and EA results showed that Cu($\alpha$)-PC, Cu($\beta$)-PC were destroyed an(1 new metal oxide such as CuO were formed.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
• /
• pp.249-251
• /
• 2014

Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4//oxygen$ mixture using two-section porous media combustor. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. $H_2/CO$ ratio and module M from concentration of flue gas measured by Gas Chromatography was similar to those calculated by equilibrium. But it was made sure that the heat loss effect becomes more influential than heat recirculation effect as the mixture gets richer. To generate synthesis gas appropriate for methanol production, insulated pressurized porous media combustor will be designed and built in the future.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
• /
• pp.137-138
• /
• 2012

The two-equation soot model based on the transient laminar flamelet model is implemented for soot formation of laminar non-premixed $CH_4/Air$ flame with detailed chemical reaction mechanism and complex thermodynamic properties. The soot model represents nucleation, growth and oxidation with gas-phase chemistry. This represented unsteady flamelet soot model has been tested and compared using well verified reference calculation result obtained solving the Full Transport Equations method.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
• /
• pp.73-74
• /
• 2015

Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4/oxygen$ mixture using insulated pressurized porous media combustor. Experimentally, two cylindrical SiC foams with the different pore density were piled up in a quartz tube and fully premixed mixture was supplied in the axial direction. After stabilizing fuel-rich flame at the interface of the two foams at several pressure conditions, mole fractions of synthesis gases were measured by gas chromatography. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. As the pressure increased, the rich flammability limit, $H_2/CO$ ratio, and module M increased.

• 한국산학기술학회논문지
• /
• 제18권5호
• /
• pp.708-715
• /
• 2017

최근에 엄격한 배기가스규제를 충족시키기 위해 자동차와 선박용 후처리장치의 비중이 점차로 증가하고 있다. 이 연구의 목적은 CNG 버스에서 배출되는 유독성 가스를 저감하는 NGOC의 $CH_4$ 저감능력 향상을 연구하는 것이다. 13종의 천연가스산화촉매(NGOC)를 제조하였고, 지지체(support)의 종류, 귀금속의 담지량 영향 및 계면활성제와 열화에 따른 유해가스 전환 성능을 파악하였다. 3번 $NGOC(1Pt-1Pd-3MgO-3CeO_2/(46TiO_2+23Al_2O_3+23Zeolite)$에 담지된 지지체 Zeolite는 음이온 알칼리금속/토금속 성분으로 CO와 NO와의 산화반응성 및 귀금속 분산도를 향상시켜 $CH_4$ 저감능력을 향상시켰다. Pd는 $CH_4$에 대한 선택도가 큰 귀금속이며, 담지량이 증가할수록 반응사이트가 더 많아져 $CH_4$ 저감 능력이 향상되었다. Pt 11wt%가 담지된 9번 NGOC(11Pt-6Pd-3MgO/(40Zeolite+$40Al_2O_3$)의 경우, 과하게 담지된 Pt 담지량은 오히려 CO와 NO 전환율이 감소하였으며, 이는 Pt 분산도 저하 및 CO와 NO 산화반응에 선택적인 Zeolite 함량이 감소하였기 때문이다. 계면활성제가 첨가된 11번 NGOC(1Pt-1Pd-3MgO-$3CeO_2$/(Z 20+Al80)(pH=8.5)가 촉매 입자의 분산이 잘되어있고, 응집(agglomeration)되지 않아 $CH_4$ 저감 능력이 5-15% 향상되었다. Mild하게 48h 열적 열화된 13번 NGOC(2Pt-2Pd-3Cr-3MgO/$90Al_2O_3$)(48h aging)는 12번 NGOC(Fresh)에 비해 $CH_4$ 저감 능력이 약 10% 이하로 상승하였다.

• 한국미생물·생명공학회지
• /
• 제49권2호
• /
• pp.225-238
• /
• 2021

옥수수(Zea mays)와 톨페스큐(Festuca arundinacea) 근권 토양을 접종원으로 사용하여 농화배양을 통해 CH₄ 산화컨소시움과 N₂O 환원 컨소시움을 얻었다. Illumina MiSeq 염기서열 분석법으로 접종원과 컨소시움의 세균 군집 특성을 비교하였고, 컨소시움의 CH₄ 산화와 N₂O 환원 활성에 미치는 뿌리삼출물의 영향을 규명하였다. 접종원이 다름에도 불구하고 옥수수와 톨페스큐 유래 CH₄ 산화 컨소시움 사이의 유사성이 높았고, 2종의 N₂O 환원 컨소시움도 서로 유사성이 높았다. 2종의 CH₄ 산화 컨소시움에서 우점도가 높은 metanotrophs는 Methylosarcina, Methylococcus 및 Methylocystis이었다. 2 종의 N₂O 환원 컨소시움에서 대표적인 N₂O 환원 세균은 Cloacibacterium, Azonexus 및 Klebsiella이었다. 옥수수 근권 유래 N₂O 환원 컨소시움의 N₂O 환원 속도는 옥수수 뿌리삼출물 첨가에 의해 1.6배, 톨페스큐 유래 컨소시움의 N₂O 환원 속도는 톨페스큐 뿌리삼출물 첨가에 의해 2.7배 향상되었다. 그러나 CH₄ 산화 컨소시움의 활성은 뿌리삼출물 첨가에 의해 향상되지 않았다. 본 연구의 옥수수 및 톨페스큐 근권 유래 CH₄ 산화 및 N₂O 환원 컨소시움은 유류 오염 정화과정에서 non-CO₂ 온실가스배출을 저감하는데 활용 가능하다.