• 플랜트 저널
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• 제13권3호
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• pp.36-46
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• 2017

황회수 공정의 연소반응기 안에서는 평형반응 및 kinetic 반응이 동시에 일어난다. 주요 kinetic 반응에 참여하는 성분들은 수소($H_2$), 일산화탄소(CO), 카보닐황화물(COS) 그리고 이황화탄소($CS_2$) 이다. 본 연구에서는 평형반응, 상관관계식(empirical correlations) 그리고 황 회수 공정의 라이센서 자료의 비교를 통해 반응기에서 kinetic components (COS와 $CS_2$)의 생성 양을 분석한다. 또한 kinetic components ($H_2$ 와 CO)의 생성 양의 분석을 통해 반응기에서의 생성 양과 온도와의 상관관계를 분석한다. 부 반응이 전체 연소에 필요로 하는 산소의 양에 어떤 영향을 미치는지도 같이 분석을 한다. 황회수 공정의 반응기내의 부 반응에 대한 충분한 이해는 전체 황회수 공정 설계를 할 때 최적의 장치 설계를 가능하게 하고 나아가 황회수 효율을 극대화 하는데 도움이 된다.

• 공업화학
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• 제16권2호
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• pp.282-287
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• 2005

팔라듐 분리막은 수소에 대한 선택적 투과성능이 우수하여 수소의 분리 정제와 막반응기에 많이 이용된다. 무전해 도금법에 의해 팔라듐을 다공성 세라믹막 표면위에 도금하고 내구성을 향상하기 위한 후처리로서 사염화 티탄($TiCl_4$)을 이용한 에칭으로 팔라듐-세라믹 복합막을 제조하였다. 제조된 팔라듐-세라믹 복합막을 막반응기로 이용하여 수성가스전환반응에 적용하였으며, 여러 가지 실험 변수에 따른 CO 전환율을 조사하였다. 막반응기를 사용하지 않은 전통적인 반응기와 비교한 결과, 적정조건에서 막반응기의 CO의 반응전환율이 20~25% 이상 향상되었다. 막반응기에서의 수성가스반응은 120 h의 운전 결과, CO의 반응전환율이 변함없이 안정적으로 유지되었다.

• 대한화학회지
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• 제25권5호
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• pp.291-299
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• 1981

용액중에서 화학반응을 설명하기 위하여 한개의 대표적인 입자의 반복적 충돌현상까지 고려한 동역학적인 이론을 경구모델을 사용하여 연구하였다. 반응성을 지닌 대표적인 입자의 상공간 밀도의 시간상관함수가 만족시키는 동역학방정식을 유도하였고 이로부터 비활성 용매 S중에서 일어나는 A + B ${\rightleftharpoons$ C + D 형태의 가역반응에 관계되는 반응속도 계수의 인자를 투영연산자방법으로 구하였다.

• Bulletin of the Korean Chemical Society
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• 제7권6호
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• pp.448-453
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• 1986

Two contributions to the activation barrier of the $S_N2$ reaction, intrinsic and thermodynamic, are discussed in connection with the predictive power of various rate-equilibrium relationships. It has been shown that the PES models can only give correct predictions of changes in structure and energy of the transition state if the activation barrier is dictated by the thermodynamic factor. We concluded that the identity and dissociative $S_N2$ reactions are dominated by the intrinsic component while associative $S_N2$ reactions are predominantly of thermodynamic controlled. Thus in the former cases, the PES models fail, whereas in the latter cases predictions based on the intrinsic factor, the quantum mechanical models, fail. Finally in a general case of equal contributions by thermodynamic and intrinsic factors, the $SN_2$ reaction proceeds by a synchronous process with zero net charge on the reaction center, for which predictions of substituent effects will be the same as for the intrinsic control case.

• 한국응용과학기술학회지
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• 제25권4호
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• pp.418-428
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• 2008

Transesterification of fat of Tra catfish with methanol in the presence of the KOH catalyst yields fatty acid methyl esters (FAME) and glycerol (GL). The effects of the reaction temperature and reaction time on rate constants and kinetic order were investigated. Three regions were observed. In the initial stage, the immiscibility of the Tra fat and methanol limited the reaction rate, hence this region was controlled by the mass transfer. Subsequent to this region, produced FAME like a co-solvent made the reaction mixture homogeneous, therefore the conversion rate increased rapidly so it was controlled by the kinetic parameters of the reaction until the equilibrium was approached in the final slow region. A second-order kinetic mechanism was proposed involving second regions for the forward reaction. The rate determining step for the overall KOH catalyzed-methanolysis of Tra fat was the conversion of triglycerides (TG) to diglycerides (DG). This rate constant was increased from 0.003 to $0.019min^{-1}$ when the reaction temperature was increased from 35 to $60^{\circ}C$. Its calculated activation energy was 14.379 ($kcal.mol^{-1}$).

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.731-732
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• 2003

Mutagen X (MX), 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone is one of the most potent directing acting mutagen ever tested in SAL TA100 assay. Although MX analogues have been synthesized, tested for mutagenicity and modeled by structure-activity relationship (SAR) methods, the mechanism of interaction of these compounds with DNA to produce their remarkable mutagenic potency remains unresolved. MX exists as an equilibrium mixture of both ring and open form in water. This equilibrium is very fast for Ames test. Because the mixture is not separable by experimental methods, it is not clear which one is really responsible for the observed mutagenicity. There have been many debates that which one is really responsible for the observed mutagenicity. We used ab initio methods for the MX analogues. It seems both ring and open form could react with DNA bases as electrophiles. However, every open form has consistently lower LUMO energy than corresponding ring form. It is reasonable to assume that the major reaction will go through via open form for MX analogues. This suggest that the open form is more likely really mutagenic.

• 에너지공학
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• 제2권3호
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• pp.276-284
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• 1993

분류층 가스화기를 대상으로하여 석탄가스화 복합발전 시스템을 위한 가스화반응 모델링을 수행하였다. 가스화기 내에서의 가스화반응은 화학평형상태에 있다고 가정하여 Gibbs 자유에너지 최소화법을 이용하였다. 물질수지와 열수지를 동시에 고려한 모델링 결과와 실제 가스화기 실험자료를 비교하여 모델의 신뢰성을 확인하였다. 이를 토대로 가스화기에 공급되는 산화제의 양이 평형조성에 미치는 영향과 가스화기의 온도, 그리고 석탄종류가 가스화반응에 미치는 영향에 대해 알아보았다.

• Bulletin of the Korean Chemical Society
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• 제18권7호
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• pp.749-754
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• 1997

Rate constants have been measured spectrophotometrically for the reactions of alkali metal ethoxides (EtOM) with S-p-nitrophenyl 2-thiofuroate (1b) and 2-thiophenethiocarboxylate (2b) in absolute ethanol at 25.0±0.1 ℃. 1b is observed to be more reactive than 2b toward all the EtOM studied. The reactivity of EtOM is in the order EtOK > EtONa > EtO- > EtOLi for both substrates, indicating that K+ and Na+ behave as a catalyst while Li+ acts as an inhibitor in the present system. Equilibrium association constants of alkali metal ions with the transition state (KaTS) have been calculated from the known equilibrium association constants of alkali metal ion with ethoxide ion (Ka) and the rate constants for the reactions of EtOM with 1b and 2b. The catalytic effect (KaTS/Ka) is larger for the reaction of 1b than 2b, and decreases with decreasing the size of the alkali metal ions. Formation of 5-membered chelation at the transition state appears to be responsible for the catalytic effect.

• 한국표면공학회지
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• 제23권1호
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• pp.27-33
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• 1990

Thermodynamic analysis on silicon consumpton during the chemical vapor deposition of tungten was carried out by calculation equilibrium concerations of all possible product species utilizing a computer progrom according to VCS.(Villars-Cruise-Smith) algorithm. The calculation could show various reaction paths which dominate the tungsten deposition under different process conditions. According to the calculation, the consumption of silicon can also be reduced at a lower total pressure SiH4 without H2 as the reacting gas is most effective for suppression of the excessive consumption of silicon during the deposition process.

• Bulletin of the Korean Chemical Society
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• 제16권6호
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• pp.479-483
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• 1995

The synergistic extraction of palladium(Ⅱ) was studied with 1,2-dichloroethane containing thenoyltrifluoroacetone (TTA; HA) and tri-n-octylphosphine oxide (TOPO; S). The main composition of synergistic adduct extracted into 1,2-dichloroethane phase was found to be PdA2S2. The equilibrium constants of the synergistic reaction were calculated. The application of this method to synthetic mixture for the separation of Pd from Pt was developed.