• Journal of Integrative Natural Science
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• v.5 no.3
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• pp.175-181
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• 2012

Oxepane high explosives substituted to explosive group such as azido, nitrato and hydrazino are investigated theoretically the acid catalyzed reaction using the semiempirical MINDO/3, MNDO and AM1 methods to use as the guidelines of high explosives. The nucleophilicity and basicity of oxepane high explosives can be explained by the value of negative charge on oxygen atom of oxepane and the reactivity in propagation step can be represented by the value of positive charge on carbon atom and low electrophile LUMO energy. It was known that carbenium ion was favorable due to the stable energy (19.507~32.101 Kcal/mol) between oxonium ion and carbenium ion in the process of cyclic oxonium ion of oxepane high explosives being converted to open carbenium ion in oxepane high explosives. The value of concentration of cyclic oxonium ion and open carbenium ion in equilibrium status was found to be a major determinant of mechanism, it was expected to react faster in the prepolymer propagation step in SN1 mechanism than in that of $S_N2$.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.278-283
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• 2010

The cationic polymerization of oxolane high explosives which have pendant explosive groups such as azido, nitrato and hydrazino is investigated theoretically using the semiempirical MINDO/3, MNDO and AM1 methods. The nucleophilicity and basicity of oxolane high explosives can be explained by the negative charge on oxygen atom of oxolane. The reactivity of propagation in the polymerization of oxolane can be represented by the positive charge on carbon atom and the low LUMO energy of active species of oxolane. The reaction of the oxolane high explosives in oxonium ion form to the open chain carbenium ion form is expected by computational stability energy (17.950~30.197 kcal/mol) of the oxonium ion and carbenium ion favoring the carbenium ion. The relative equilibrium concentration of cyclic oxonium ion and carbenium ion is found to be a major determinant of mechanism, owing to the rapid equilibrium of these catoinic forms. Based on calculation, in the prepolymer propagation step, $S_N1$ mechanism will be at least as fast as that for $S_N2$ mechanism.

• Journal of Integrative Natural Science
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• v.7 no.4
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• pp.266-272
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• 2014

Oxocane high explosives substituted to explosive group such as azide (-CH2N3), nitrate (-CH2ONO2), and hydrazine (-CH2N2H3) are investigated theoretically the acid catalyzed reaction using the semiempirical MINDO/3, MNDO and AM1 methods to use as the guidelines of high explosives. The nucleophilicity and basicity of oxocane high explosives can be explained by the value of negative charge on oxygen atom of oxocane and the reactivity in propagation step can be represented by the value of positive charge on carbon atom and low electrophile LUMO energy. It was known that carbenium ion was favorable due to the stable energy (11.745~25.461 Kcal/mol) between oxonium ion and carbenium ion in the process of cyclic oxonium ion of oxocane high explosives being converted to open carbenium ion in oxocane high explosives. The value of concentration of cyclic oxonium ion and open carbenium ion in equilibrium status was found to be a major determinant of mechanism, it was expected to react faster in the prepolymer propagation step in SN1 mechanism than in that of SN2.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.636-644
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• 1991

The cationic polymerization of substituted oxethanes which have pendant energetic groups such as methoxy, azido, and nitrato are investigated theoretically using the semiempirical MINDO/3, MNDO, and AM1 methods. The nucleophilicity and basicity of substituted oxethanes can be explained by the negative charge on oxygen atom of oxetanes. The reactivity of propagation in the polymerization of oxetanes can be represented by the positive charge on carbon atom and the low LUMO energy of active species of oxetanes. The reaction of the energetic cyclic oxonium ion forms to the open chain carbenium ion forms is expected by computational stability energy of the oxonium and carbenium ion (about 10~20 kcal/mole) favoring the carbenium ion. The relative equilibrium concentration of cyclic oxonium and open carbenium ions is found to be a major determinant of mechanism, owing to the rapid equilibrium of these cation forms and the expectation based on clauclation that the prepolymer propagation step SN1 mechanism will be at least as fast as that for SN2 mechanism.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.461-468
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• 1991

The cationic polymerizations of substituted oxiranes which have pendant energetic groups such as azido, and nitrato, are investigated theoretically using the semiempirical MNDO, and $AM_1$ methods. The nucleophilicity and basicity of substituted oxiranes can be explained by the negative charge on oxygen atom of oxiranes. The reactivity of propagation in the polymerization of oxiranes can be represented by the positive charge on carbon atom and the low LUMO energy of active species of oxiranes. Ring opening of the complexed cyclic oxonium ion to the open chain carbenium ion is expected computational stability of the oxonium and carbenium ion by 30∼40 kcal/mol favoring the carbenium ion. The relative equilibrium concentration of cyclic oxonium and open carbenium ions will be a major determinant of mechanism. The chain growth $SN_1$, mechanism will be at least as fast as that for $SN_2$ mechanism.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.159-164
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• 2009

Monomers of oxetane high explosives were theoretically examined in terms of reactivity, reaction mechanism and process of polymerization substituted by azido $(-CH_2N_3)$, nitrato $(-CH_2ONO_2)$ and hydrazino $(-CH_2N_2H_3)$ which belong to the 5th class hazardous materials and have explosiveness under acid catalyst using MINDO/3, MNDO, and AMI methods for formal charge, heat of formation, and energy level. Nucleophilicity and base of oxetane high explosives could be explained by negative charge size of oxetane oxygen atom and reactivity of oxetane in the growth stage of polymerization under acid catalyzer could be expected to be governed by positive charge size of axial carbon atom and low LUMO energy of electrophile. It could be estimated that carbenium ion was more beneficial in the conversion process of oxetane high explosives than that of stabilization energy (13.90~31.02 kcal/mole) of oxonium ion. In addition, concentration of oxonium ion and carbenium ion in equilibrium state influenced mechanism and it was also estimated that $S_N1$ mechanism reacts faster than that of $S_N2$ in prepolymer growth stage considering quick equilibrium based on form and calculation of polymerization under acid catalyzer.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.197-204
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• 1992

The cationic polymerization of cyclic acetals are investigated theoretically using the semiempirical MINDO/3, MNDO, and $AM_1$, methods. The nucleophilicity and basicity of cyclic acetals can be explained by the negative charge on oxygen atom of cyclic acetals. The reactivity of propagation in the polymerization of cyclic acetals can be represented by the positive charge on $C_2$ atom and the low LUMO energy of active species of cyclic acetals. The reactivity of 2-buthyl-1,3-dioxepane(2-Bu-DOP) of cyclic oxonium and opening carbenium ion form is expected computational stability of the oxonium ion by 5${\sim}$7kcal/mole favoring the carbenium ion. Owing to the rapid equilibrium of these cation forms and the reaction coordinate based on calculation that the reaction coordinate based on calculation that the chain growth $S_N1$ mechanism will be at least as fast as that for $S_N2$ mechanism.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.107-111
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• 2002

The OSS2 (Oj？me-Shavitt-Singer 2)[L. Oj？me et al., J. Chem. Phys. 109, 5547 (1998)] model for the solvated proton in water is examined for $H_2O,\;H_3O^+,\;H_5O_2^+,\;H_7O_3^+,\;and\;H_9O_4^-$ by molecular dynamics (MD) simulations. The equilibrium molecular geometries and energies obtained from MD simulations at 5.0 and 298.15 K agree very well with the optimized calculations.

• Fibers and Polymers
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• v.1 no.1
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• pp.1-5
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• 2000

Poly(3-methyltetrahydrofuran)(3-MTHF) and poly(tetrahydrofuran-co-3-MTHF), having very narrow molecular weight distribution were successfully synthesized via photo-induced living cationic polymerization in the presence of diphenyliodonium hexafluorophosphate. Linear relationship between % conversion and number average molecular weight of resulting poly(3-MTHF) in the polymerization of 3-MTHF, carried out at -22$^{\circ}C$, indicates that the 5-membered cyclic oxonium ion, being responsible for the cationic propagation is stabilized by ion pall formation with hexafluorophosphate anion, supplied from the salt. The linear relationship between two parameters, mentioned above was also observed in the copolymerization of 3-MTHF with THF, carried out at 0 and -22$^{\circ}C$. The molecular structures including the copolymer composition and average molecular weight and its distribution is determined by reaction parameters such as monomer feed ratio and reaction temperature.

• Journal of the Korean Wood Science and Technology
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• v.42 no.2
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• pp.183-192
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• 2014

For the structure determination of D-(+)-sucrose, which consists of ${\alpha}$-D-(+)-glucose and ${\beta}$-D-(+)-fructose, it was acetylated with acetic anhydride and triethyl amine, pyridine, zinc chloride, and sodium acetate as catalysts. The acetylated D-(+)-sucrose was acid-hydrolyzed using sulfuric acid and sodium chloride in methanolic solution. The structures of the reaction products were determined by $^1H$-NMR and $^{13}C$-NMR spectra. The yield of the acetylation indicated the high value in zinc chloride as 70% in zinc chloride catalyst. The acid-hydrolyzed product of the acetylated D-(+)-sucrose, 2,3,4,6,1',3',4',6'-octa-O-acetyl-D-(+)-sucrose, gave 2,3,4,6-tetra-O-acetyl-${\beta}$-D-(+)-glucose and it suggests that the acetylated D-(+)-sucrose was rearranged through the formation of oxonium ion by mutarotation in the 2,3,4,6-tetra-O-acetyl-${\alpha}$-D-(+)-glucose moiety and through the ring opening in the 1',3',4',6'-tetra-O-acetyl-${\beta}$-D-(+)-fructose moiety.