• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.284-284
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• 2012

In this study, $V_2O_5/TiO_2$ catalyst was measured reactivity of ethanol when vanadia ratio was increasing. First, $V_2O_5/TiO_2$ catalyst was prepared to the increasing vanadia ($VO_x$) ratio as 0.2, 1, 10 wt%. And we were used X-ray diffraction (XRD), then not appear markedly peak to pure vanadia about XRD analysis. So we were decided vanadia that was evenly dispersed on $TiO_2$. Result about temperature-programmed reduction (TPR) analysis was obtained 3 reactions that was dehydrogenationfrom obtained to acetaldehyde, dehydration from obtained to ethylene, condensation from obtained to diethyl ether. If vanadia ratio was increasing in $V_2O_5/TiO_2$, reactions temperature of ethanol was known lower. And condensation into diethyl ether is quenched away with increasing vanadia loading. In addition, competition between reductive dehydration and oxidative dehydrogenation occurs, while the selectivity toward dehydrogenation is favored with increasing vanadia loading.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.684-690
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• 2013

Since a glycerol molecule has three active sites, two ${\alpha}$ and one ${\beta}$ hydroxyl groups; it undergoes condensation by releasing water molecules to produce linear, nonlinear and heterocyclic oligomers. The Gibbs free energy (G), enthalpy (H) and internal energy (E) of 7 diglycerol, 15 triglycerol and 23 tetraglycerol isomers were calculated at B3LYP level of theory using 6-311++G(d, p) basis set, in both gas and aqueous phases. Linear oligomers, ${\alpha}{\alpha}$-diglycerol, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-triglycerol and ${\alpha}{\alpha}$, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-tetraglycerol, were found to be the most stable oligomers in aqueous phase. It was found that the stability of cyclic oligomers decreases as the size of their rings increases. Cyclic oligomers are produced by dehydration of the acyclic ones which is an endothermic reaction while its ${\Delta}G$ is negative. The dehydration reaction is less endothermic in aqueous phase.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.594-598
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• 2011

We study on the preparation of green emitting materials for organic light emitting device. 3-chromonealdehyde derivatives possessing a conjugated structure, which were composed of electron acceptor of 3-chromonealdehydes and electron donor of diamines, were synthesized by dehydration-condensation process. The structural properties of reaction products were analyzed FT-IR and $^1H-NMR$ spectroscopy. The thermal stabilities and reactivities were measured by melting points and yields. The UV-visibles and PL properties can be determined by excitation spectra and emission spectra, respectively.

• Clean Technology
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• v.16 no.2
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• pp.95-102
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• 2010

Sulfonic acid (-SO3H) functionalized mesoporous silica containing HMS, SBA 15(S15), MCM 41(M41) were synthesized by post-synthesis and co-condensation method. Their catalytic performance is tested by dehydration reaction of D-xylose to furfural. As a result, good conversion and selectivity was obtained using water as an environmentally friendly solvent. Additionally, increased amounts of sulfuric acid in catalysts resulted in improved conversion of D-xylose. All of the acid-functionalized mesoporous silica showed higher selectivity than other solid acids such as ${\gamma}-Al_{2}O_{3}$ and zeolite.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.360-367
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• 1997

The chemistry background of the Maillard reaction focused on pyrazines and factors affecting the reaction products were reviewed. The Maillard reaction, also called a non-enzymatic browning reaction, is quite complex and generates numerous reaction products. In processed foods, it is generally accepted as a key reaction to produce flavor components. Specially, pyrazines possess an important impact character on the roasted foods with other heterocyclic compounds. The Maillard reaction is initiated by condensation between reducing sugar and amino group, and N-glycosylamines are produced via Schiff base with dehydration of water. After the rearrangement of the N-glycosylamines, they follow transformation into deoxyhexosones which are reactive intermediates. Degradation and fragmentation are facilitated by rearranged compounds. By condensation, pyrazine, one of the final Maillard products, is generated as a relatively stable form to provide specific aromas. During the processes of the reaction, chemical or physical environmental parameters affect the formation of the products.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.205-209
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• 2003

The condensation water temperature $(T_{CW})$ distributions on the combi-drum washer of condensation type which the cloth washes, rinses, spins and dry cloth over a heater were measured using the thermocouples. During the drying process, in order to find out the relationship between the $T_{CW}$ distribution and the cloth dryness level $(C_{D1})$, the experiment was made for the dehydration rate of the cloth $(C_{D0})$ is 63%, the weight of cloth $(W_{C0})$ from 1 to 6kg. In result, according to $W_{C0}$ and $C_{D0}$, the distributions of $T_{CW}$ are very different. Using this tendency, it was appropriate and it developed the automatic drying algorithm and it was gotten dryness level regardless of $W_{C0}$, $C_{D0}$ and the other factor.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.61-66
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• 1985

The preparation of 2-(2,2,2-trichloroethylidene)cyclohexanone(1), as a key compound for synthesizing 2-substituted 5,6,7,8-tetrahydro-3-cinnolinones, was attempted by the enamine condensation of cyclohexanone with chloral. However, the condensation of 1-morpholino-1-cyclohexene (2) with chloral afforded 2-(1-hydroxy-2,2,2-trichloroethyl) cyclohexanone (3), and its dehydration led to 2-(2,2-dichlorovinyl)-2-cyclohexenone (4). 2-Aryl-5,6,7,8-tetrahydro-3-cinnolinones could be synthesized using morpholinium ${\alpha}$-(4-morpholinyl)-${\alpha}$-(2-oxocyclohexyl)-acetate (5) in place of 1 with arylhydrazines.

• Journal of the Korean Chemical Society
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• v.19 no.1
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• pp.38-42
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• 1975

Chloral-2-acetothienone was synthesized from the condensation of 2-acetothienone with chloral, and trichloroethylidene-2-acetothienone was obtained from the dehydration of chloral-2-acetothienone. From the reaction of trichloroethylidene-2-acetothienone with phenylhydrazine or substituted phenylhydrazines 2-aryl-6-(2-thienyl)-3(2H)-pyridazinones were obtained. 3-(2-Thienyl)-5-trichloromethyl-2-pyrazoline was synthesized from the reaction of trichloroethylidene-2-acetothienone with hydrazine hydrate.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.297-302
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• 1999

In situ measurement of infrared absorption spectra has been performed during low-temperature plasma-enhanced chemical vapor depositiion of silicon-oxide films using tetramethoxysilane as a silicon source. Several absorption bands due to the reactant molecules are clearly observed before deposition. In the plasma, these bands completely disappear at any oxygen mixing ratio. This result shows that most of the tetramethoxysilane molecules are dissociated in the rf plasma, even C-H bonds. Existence of Si-H bonds in vapor phase and/or on the film surface during deposition has been found by infrared diagnostics. We observed both a decrease in Si-OH absorption and an increase in Si-O-Si after plasma off, which means the dehydration condensation reaction continues after deposition. The rate of this reaction is much slower than the deposition ratio of the films.

• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.31-35
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• 1991

Three isomers of damascenone, odorous terpenic ketones, have been synthesized conveniently from a same starting material, ethyl 2,6,6-trimethyl-4-oxo-2-cyclohexene-1-carboxylate(1), which was easily available by the acid-catalyzed condensation of mesityl oxide or acetone with ethyl acetoacetate. ${\alpha}$-Damascenone(7) was prepared by converting the enone ester 1 into the corresponding tosylhydrazone(4), followed by treating with 4 molar equiv of allyllithium. ${\beta}$-Damascenone(12) was synthesized by chemoselective reduction of 1 with sodium borohydride/cerium chloride to give corresponding allylic alcohol 8, conversion of 8 into acetate 9, and thermal decomposition of 9 with DBU to afford ethyl ${\beta}$-safranate(10), followed by reaction with an excess amount of allyllithium. ${\gamma}$-Damascenone(15) was obtained by dehydration of 8 with boric acid to furnish ${\gamma}$-safranate(13), followed by treatment with 2 molar equiv of allyllithium.