• Bulletin of the Korean Chemical Society
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• 제25권11호
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• pp.1653-1656
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• 2004

${\alpha},{\beta}$-Unsaturated aldehydes such as acrolein and crotonaldehyde were reacted with diols in the presence of conc. sulfuric acid to give products of which concomitant addition to C-C double bond and acetalization took place. Boron trifluoride etherate and titanium tetrachloride gave only acetalization products.

• Korean Chemical Engineering Research
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• 제53권4호
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• pp.463-467
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• 2015

We investigated catalytic activity of ion-exchange resins in acetalization of 1,2-propylene glycol with acetaldehyde. The impacts of reaction variables, such as temperature, reaction time, catalyst loading and feedstock composition, on the conversion of 1,2-propylene glycol were measured. The life of the catalyst was also studied. Furthermore, the reaction kinetics of 1,2-propylene glycol acetalization was studied. It was found that reaction rate followed the first-order kinetics to acetaldehyde and 1,2-propylene glycol, respectively. Therefore, overall acetalization reaction should follow the second-order reaction kinetics, expressed as. Key words: 1,2-propylene Glycol, 2,4-dimethyl-1,3-dioxolane, Ion-exchange Resin, Polyhydroxy Compounds, Acetalization $r=kC^{nA}_AC^{nB}_B=19.74e^{\frac{-6650}{T}}C^1_AC^1_B$.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 1부
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• pp.141-143
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• 2011

Al-SBA-1(Si/Al = 40, 80 and 120) and Al,Mg-SBA-1 (Si/(Al+Mg) = 40 and 80) molecular sieves were synthesized and characterized. Acetalization of n-heptanal with methanol was studied under autogenous pressure between 80 and $150^{\circ}C$. Since protonation of n-heptanal was fast, addition of methanol to the same to formed hemiacetal slowly whereas conversion of hemiacetal to acetal was fast. The catalysts exhibited nearly similar conversion irrespective of their difference in acidity, and all of them showed more than 80 % conversion either at 80 or $100^{\circ}C$. Hence it is evident that the difference in acidity is not so important in differentiating the activity of the catalysts. The large pore size and hydrophilic and hydrophobic properties are suggested to be the main factors that control acetalization.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.865-868
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• 2004

Aldehydes and ketones were converted to their corresponding acetals in the presence of silica-bound sulfuric acid in n-hexane under mild and heterogeneous conditions with excellent yields.

• 폴리머
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• 제26권2호
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• pp.168-173
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• 2002

폴리비닐알코올(PVA)을 부틸알데히드로 아세탈화하여 폴리비닐부티랄(PVB)을 합성하였다. PVB는 물을 용매로 침전법에 의하여 입자형태로 제조되었으며 생성된 PVB의 화학적 물리적 특성을 여러 방법을 이용하여 분석, 측정하였다. 제조된 PVB입자는 100~700 $\mu\textrm{m}$의 입도분포내에서 약 380$\mu\textrm{m}$의 평균입자크기를 나타내었다. PVB의 화학구조는 FT/IR과 NMR을 이용하여 확인할 수 있었으며 적정분석 결과 아세탈화정도는 약 77%로 나타났다. DSC 분석결과 PVA가 PVB로 아세탈화됨에 따라 PVA의 결정성이 사라졌으며, 유리전이온도가 $70^{\circ}C$근처에서 나타났다. TGA 분석결과 제조된 PVB는 반응물인 PVA에 비해 열적으로 매우 안정하여 $300^{\circ}C$까지 열분해를 보이지 않았다. 용해도 분석결과 PVB는 PVA와는 달리 알콜류에는 용해되었으나 물에는 용해되지 않았다.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.278-283
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• 1999

Formaldehyde has widely been used for the cross-linking of polyvinyl alcohol polyvinyl alcohol polymer. The effects of formaldehyde on the water resistance of MDF cement composites were investigated as a function of types of catalyst, base or acid, and the amount of formaldehyde. The acetalization, reaction of OH group of PVA with aldehyde, was ended incompletely under base atmosphere. However, by addition of citric acid, the cross-linking of PVA polymer could be acheved through acetalization of PVA and formaldehyde. The effects of these different patterne according to the types of catalyst on the water resistance of MDF cement were studied by the preparation of PVA films and MDF composites. Thanks to the cross-linking reaction of PVA polymer chains by formaldehyde, the modified PVA films and MDF composites showed a good water-resistant propety. The modified MDF cement composite to which 3 wt% formaldehyde and 1 wt% cirtic acid were added showed 80% of initial flexural strength and good interfacial state between cement grain and polymer matrix. However, 4 wt% formaldehyde deteriorted the processing conditions, microstructures and eventually the flexural strength, causing sharp increase in the viscosity of sample dough during the mixing process. To study the relatins of flexural strength and interface of cement grain and polymer matrix, SEM and MIP measurement were performed.

• Bulletin of the Korean Chemical Society
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• 제17권4호
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• pp.362-365
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• 1996

Carbonyl compounds 1, alkyl- and arylaldehydes and alkyl, aryl, benzylic, and cyclic ketones were converted to the corresponding 1,3-dioxolanes 2 and 1,3-dioxanes 4 with ethylene glycol and 2,2-dimethyl-1,3-propanediol in the presence of 1-3 mol% of 1-(p-substituted)benzyl-1,1-dimethyl-2-(p-substituted)-benzoyl hydrazinium hexafluoroantimonates 3 in high yields.

• 약학회지
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• 제35권6호
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• pp.497-503
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• 1991

Six novel 5-substituted-1-[2-(3-methoxy-2-hydroxyphenyl)-1-methoxyethyl]uracils 2a-f were prepared by condensation of 2,4-bis(trimethylsilyloxy)-5-substituted uracils with 2,7-dimethoxy-2,3-dihydrobenzofuran (9) in the presence of Lewis acid. The 2,3-dihydrobenzofuran derivative 9 was obtained by intramolecular acetalization of 2-acetoxy-3-methoxyphenyl acetaldehyde (8) which was synthesized by oxidative cleavage of 1-allyl-2-acetoxy-3-methoxybenzene (7) using osmium tetroxide followed by $NaIO_4$. Compounds 2a-f were evaluated for in vitro antiviral activity against HSV-1, HSV-2 and HRV. None of these compounds showed activity with $ID_{50}$ values up to $100\;{\mu}g/ml$ except for 5-chlorouracil derivative 2d which exhibited antiviral activity against HSV-1 with $ED_{50}$ $30\;{\mu}g/ml$. In the antitumor activity against L1210 and P388 leukemia cell lines, 2d showed activity with $ID_{50}$ values of $14\;{\mu}g/ml$ and $11.6\;{\mu}g/ml$, and 2c with $ID_{50}$ values of $22.9\;{\mu}g/ml$ and $8.8\;{\mu}g/ml$, respectively.