• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.621-634
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• 2001

The characteristics of enzymatic methanolysis of castor oil were investigated as a clean technology. Among 16 lipases tested in this study, Novozym 435 showed the highest activity in methanolysis. Solvents had different effects on the methanolysis of castor oil according to weight percent (wt%) of Novozym 435. Heptane showed best activity with 1 wt% of Novozym 435, while isopropyl ether gave the best yield of ricinoleic acid methyl ester with 0.5 wt% of that. Ricinoleic acid methyl ester was obtained in 86% of yield through the methanolysis of castor oil catalyzed by Novozym 435 (1.0 wt%) during 24hr.

• Journal of the Korean Chemical Society
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• v.24 no.2
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• pp.115-120
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• 1980

A kinetic study of the methanolysis of t-butylbromide and benzoylchloride in methanol-acetonitrile mixtures is reported. First order rate constants for the methanolysis of t-butyl bromide show maximum at $X_{MeOH}$=0.75∼0.9 and 25∼$50^{\circ}C$. Apparent second order rate constants for the methanolysis of benzoylchloride also show maximum at $X_{MeOH}$= 0.6∼0.95 and 12∼$26^{\circ}C$. The maximum rate is ascribed to the solvent structure change; the addition of acetonitrile to methanol perturbs the methanol structure increasing the free methanol molecules available to stabilize the transition state for the methanolysis of t-butylbromide and benzoylchloride. It has been shown that methanol acts as nucleophilic and electrophilic catalyst upon methanolysis of t-butylbromide and as electrophilic catalyst upon methanolysis of benzoylchloride.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3448-3450
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• 2012

• Clean Technology
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• v.13 no.4
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• pp.251-256
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• 2007

Several studies regarding depolymerization of polycarbonate waste to get the essential monomer, bisphenol A, have been reported in recent years. However, those methods have some environmental safety problems of using highly toxic organic solvents as well as product separation problem due to the use of alkali catalyst. In this study, we proposed the combination of glycolysis and methanolysis to depolymerize the polycarbonate waste. Glycolysis reaction reached at the reaction equilibrium after about 180 minat 473.15K and dissolution of the polycarbonate was found to be a rate controlling step of the reaction. The yield of BPA was improved with the aid of combination of glycolysis and methanolysis. The methanolysis was carried out at a temperature range of $303.15K{\sim}363.15K$ and MeOH/PC molar ratio $0.5{\sim}3$. The yield of BPA had a maximum at 1.0 MeOH/PC molar ratio and increased with the reaction temperature.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.921-924
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• 2006

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.674-678
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• 1991

Methanolysis of a ${\beta}$-lactam ring of a cephalosporin was simulated with AM1 semiempirical quantum mechanical calculation. The tetrahedral intermediate TD1 from an O-protonated cephalosporin and a methanol transfers the proton intramolecularly to the C-4 carboxylate to generate an oxyanion, i.e., second tetrahedral intermediate TD2, which undergoes the amide bond cleavage without further protonation on the N-5. For this cleavage a low-energy barrier TS2 was located. According to the energy diagram, tetrahedral intermediates easily undergo ring cleavage even without the protonation on the amide nitrogen.

• Journal of the Korean Chemical Society
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• v.24 no.4
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• pp.288-294
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• 1980

Methanolysis rate constants were determined for $CH_3O(CO)Cl,\;CH_3S(CO)Cl\;and\;CH_3S(CS)Cl\;in\;CH_3OH-CH_3CN$ mixtures. Results show that the rates are not predominantly influenced by the bulk solvent properties but are partly influenced by specific electrophilic solvation.Polarity of the solvent is not a dominant factor but it nevertheless plays a role in charge stabilization of the $S_N1$ like transition state. The methanolysis proceeds through $S_N1$ mechanism for $CH_3S(CS)Cl$ for which both specific solvation of leaving group by methanol and charge stabilization by a high dielectric medium are important, while for $CH_3O(CO)Cl\;methanolysis occurs\;via\;S_N2$ mechanism in which both of the solvent effects are unimportant.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1183-1188
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• 2005

Several lipases of commercial grade were screened to catalyze the methanolysis of castor oil, and an immobilized Candida antarctica (Novozym 435) had the highest activity among the lipases tested. To enhance the yield of methyl ricinoleate, several reaction parameters were optimized. The optimum temperature was $50^{\circ}C$, and the original water content of lipase was sufficient to maintain the activity of lipase, and additional water supplied inhibited the methanolysis of castor oil. Because the lipase was deactivated by methanol, the reaction was tested by three-step addition of 1 molar equivalent of methanol to the oil. However, the oil was not completely converted to its methyl esters. The final reaction mixture using 3 molar equivalents of methanol to the oil consisted of $70\%$ methyl ricinoleate, $18\%$ monoricinoleate, $11\%$ diricinoleate, and trace triricinoleate at the equilibrium state. The yield of methyl ricinoleate was $97\%$ at 6 molar ratio of methanol to the oil with 300g of castor oil and 6g of immobilized Candida antarctica at $50^{\circ}C$ within 24 h.

• Journal of the Korean Chemical Society
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• v.24 no.1
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• pp.73-79
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• 1980

N-Vinylurea(VU) was radically copolymerized with vinyl acetate (VAc). VU-vinyl alcohol (VA) copolymer, which is a water-soluble polymer with pendent urea and hydroxyl groups, was synthesized by the methanolysis of the VU-VAc copolymer.VU shows vinyl polymerization, and this result is in agreement with that of Nozakura, et al. Huggins constant for the aqueous solution of the VU-VA copolymer containing more than about 30 mole percent of VU was observed to be a high value.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.128-131
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• 1997

Primary structure of purified fucoidans was analysed by methanolysis, methylation and HT-IR measurement. Basic linkage in the fucoidans of Laminaria religiosa, sporophylls of Undaria pinnatifida, Hizikia fusiforme and Sargassum fuivellum from Korea was $(1\rightarrow3)$ linkage of fucose, but a considerable amount of $(1\rightarrow3)$ linked galactose was also found in case of the purified fucoidan from sporophylls of U. pinnatifida. Ester sulfate was substituted mainly to C-4 position of fucose and galactose.