• Journal of the Korean Chemical Society
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• v.14 no.4
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• pp.333-339
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• 1970

1) The copolymerzation of acrylamide $(M_1)$ with styrene $(M_1)$ was studied in absolute methanol solution at $50^{\circ}C$, using azobisisobutyronitrile as a initiator. The monomer reactivity ratios determined at $50^{\circ}C$ were as follows: $r_1=0.2,\;r_2=1.05$ and from these values, Q and e values for acrylamide were calculated as 0.37$(Q_1)$ and 0.45 $(e_1)$. 2) Overall activation energy of copolymer was calculated to 24.3K/cal mol, using the Arrhenius epuation. 3) Measurement of intrinsic viscosity and observation of physical properties were made on the copolymer.

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.154-156
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• 1990

The alternating copolymers of dihydropyran(DP)-maleic anhydride(MA), dihydrofuran(DF)-MA and DF-vinylene carbonate(VC) were prepared by free radical copolymerization of DP or DF with MA or VC. The reactivity ratios for poly(DF-VC) were found to be less than unity (0.05, 0.04) and its alternating sequences were obtained by feeding an equimolar amount of the comonomers at the onset of copolymerizations. The copolymers were hydrolyzed to give poly(TP-CE), poly(TF-CE) and poly(TF-HE), whose cytotoxicities against normal and tumor cells (3LL, B16) were measured in vitro.

• Advances in Traditional Medicine
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• v.1 no.2
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• pp.36-44
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• 2000

The polysaccharide fractions were isolated and purified from Phellodendron chinese SCHNEID, and antitumor activities using the melanoma B-16-derived metastatic tumors were examined at dosages of 2, 5 and 10 mg/100 g. F-7 and F-8 showed the highest tumor metastatic inhibitory activities (inhibition ratio 60 and 80% in 2 mg/100 g), and in dose of 5 mg/100 g, the inhibitory ratios were 85 and 70%, respectively. Furthermore, 10 mg/100 g of intraperitoneal (i.p.) injection gave 90 and 95% of inhibition. When the effects of polysaccharides on hypersensitivity were examined, the inhibitory activities were not markedly observed in oral administration, indicating that the polysaccharides are directly acting to immune system. Also, the polysaccharides increased the number of circulating blood leukocytes and total peritoneal exudate cells. Although implantation of tumor cells greatly decreased the productivity of antibody (antibody-mediated) and T lymphocyte reactivity (delayed-type) as 6.3 from 9.3 and 5.9 from 7.7, represented by the increase of footpad thickness, respectively. the polysaccharides elevated the reactivity of T lymphocyte in tumor-bearing mice, which were rapidly recovered by discontinuance of sample treatments. Especially, F-2, F-5, F-7 and F-8 remarkably recovered the decreased sensitivity. These results clearly indicated that the i.p. injection is much effective to suppress tumor growth than oral administration.

• Journal of the Korean Chemical Society
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• v.26 no.6
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• pp.421-426
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• 1982

Free radical-initiated copolymerization of diethyl isopropenyl phosphate (DEIPA) with vinyl acetate (VAc) and acrylonitrile (AN) was studied. The monomer reactivity ratios for the monomer pairs, determined at $60^{\cric}C$ using benzoyl peroxide as an initiator, are: ${\gamma}_1$(VAc) = 1.56, ${\gamma}_2$(DEIPA) = 0.44: ${\gamma}_1$(AN) = 15.2, ${\gamma}_2$(DEIPA) = 0.031. The values of the Alfrey-Price constants, Q and e, for DEIPA were calculated to be 0.015 and 0.39, respectively, from the VAc system, and 0.014 and 0.34, respectively, from AN/DEIPA pair. These results indicate that ${\alpha}$-methyl substituent of vinyl phosphate monomer decreases the general reactivity in free radical copolymerization. The intrinsic viscosity and number-average molecular weight of copolymers decreased as their content of DEIPA units increased, indicating a high degree of chain transfer caused by DEIPA, as previously learned in DEVPA system.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.136-141
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• 2002

Advanced zinc-based sorbents, ZA, for Hot Gas Desulfurization (HGD) process in Integrated Gasification Combined Cycle (IGCC) systems were formulated with $Al_2$O$_3$ as support to enhance the reactivity and their reactive characteristics was also investigated in this study. Changes in the physical and chemical properties of the sorbents based on both the mole ratios of ZnO/Al$_2$O$_3$ and the calcination temperatures were examined by a XRD. The results obtained in our desulfurization-regeneration cycle tests demonstrated that degradation of sorbents due to the heat generation could be improved through the optimization of the $Al_2$O$_3$ contents and of the calcination temperatures. From the durability study it is concluded that the prepared ZA sorbents with additives have the desirable features for HGD.

• Analytical Science and Technology
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• v.23 no.1
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• pp.60-67
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• 2010

A sensitive competitive heterogeneous bioluminescence immunoassay for serotonin was developed using photoprotein, aequorin as a label for the first time with the optimal assay conditions; especially, serotoninavidin conjugate was prepared by Mannich reaction and the synthetic process of serotonin-avidin conjugate was optimized by controlling the initial molar ratios of serotonin, formaldehyde and avidin (1:12,000:25). The developed bioluminescence immunoassay for serotonin showed good sensitivity (LOD of 0.68 ng/mL) with wide area of dynamic range ($5.0{\times}10^{-10}\;M\sim5.0{\times}10^{-7}\;M$). (cf. the range for serotonin in human blood serum is $151{\pm}45\;ng$/mL). In addition, cross-reactivity studies demonstrated that 5-methoxytryptamine showed some cross-reactivity (28.0%), whereas 3-methylindole, melatonin and 5-hydroxylindole-3-acetic acid showed no crossreactivity, and good recoveries were obtained in serum. Thus, this developed method provides a good tool to monitor serotonin in serum.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.11-19
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• 1996

The cationic polymerization of energetic substituted oxetanes which have pendant energetic group such as azido and nitrato are investigated theoretically, using semiempirical HF/3-21G, MINDO/3, MNDO and AM1 method. The stereo- and electronic structure of binary molecular complex composed of energetic substituted oxetane and boron trifluoride can be explain by molecular orbital theory. The reactivity of propagation in the copolymerization of oxetanes can be presented by the positive charge on carbon(C2) atom of oxetane and energy level of the lowest unoccupied molecular orbital(LUMO) of propagating species of oxetanes. The reactivity ratios for copolymerization of oxetanes are a random copolymer-zation which is agree with MO calculated and experimental results. The relative equlibrium 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 calculation that in the prepolymer propagation step, SN1 mechanism will be at least as fast as that for SN2 mechanism.

• Polymer(Korea)
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• v.30 no.1
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• pp.80-84
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• 2006

2-Biphenylyl acrylate(BPA) was synthesized by the reaction of acryloyl chloride with 2-phenylphenol (2PP). Hydrophilic copolymers with the moiety of the microbicide, 2PP, were prepared by the radical copolymerization of BPA and methacrylic acid (MA). From the compositions of the BPA unit and the MA unit in the copolymers, the monomer reactivity ratios were determined to be 0.86 for BPA and 1.21 for MA by means of Kelen-Tudos plot. This result indicates that the copolymers have a random structure. The amount of 2PP released through the hydrolysis of the copolymers was examined by UV spectrometry. The result showed that the release of 2PP increased with an increase in the hydrophilic MA content in the copolymers and with an increase in the pH of the release medium. Therefore, these results indicate that the hydrophilic polymers bearing 2-phenylphenol moiety can be controlled release microbicides.

• Polymer(Korea)
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• v.26 no.1
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• pp.9-17
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• 2002

The free radical bulk copolymerizations of perfluoroalkylethyl acrylate(FA) containing perfluoro group ($CF_3(CF_2)_nCH_2CH_2$-; n=5, 7, 9, 11) with styrene were conducted at $60^{\circ}C$ using AIBN as an initiator. Reactivity ratios($r_1$, $r_2$) were determined from monomer feed compositions and the NMR spectroscopically measured copolymer compositions using Kelen-Tudos method. The structures of copolymers were characterized with FT-IR and $^1H-NMR$ analysis. Their thermal properties investigated with DSC and TGA were decreased with increasing the content of fluorinated acrylate in the copolymer. Their surface free energies were calculated with measuring contact angles of the copolymers and PMMA blends with a small amount of them.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1353-1357
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• 2007

Second-order rate constants (kN) have been determined spectrophotometrically for reactions of Y-substituted phenyl 2-furoates (1a-h) with piperidine and morpholine in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 oC. The Brønsted-type plot exhibits a downward curvature for the reactions with strongly basic piperidine but is linear for the reactions with weakly basic morpholine. The slope of the curved Brønsted-type plot changes from -1.25 to ?0.28 as the pKa of the conjugate acid of the leaving aryloxides decreases. The pKa at the center of the Brønsted curvature, defined as pKa°, was determined to be 6.4. The aminolysis of 1a-h has been concluded to proceed through a stepwise mechanism on the basis of the curved Brønsted-type plot. The reactions of Ysubstituted phenyl cinnamates (2a-g) with piperidine resulted in a curved Brønsted-type plot with a pKa° values of 6.4. However, the curved Brønsted-type plot has been suggested to be not due to a change in the RDS but due to a normal Hammond effect of a concerted mechanism, since the Brønsted-type plot for the corresponding reactions with morpholine results in also a curved Brønsted-type plot with a pKa° values of 6.1. The furoates with a basic leaving group (i.e., 1b-g) are less reactive than the corresponding cinnamates (i.e., 2b-g). The k2/ k-1 ratios for the reactions of 1b-h are much smaller than unity, which has been suggested to be responsible for their low reactivity.