간행물

한국응용과학기술학회지 KCI 등재 The Korean Society of Applied Science and Technology

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Vol.15 No.2 (1998년 6월) 11

1.
1998.06 구독 인증기관 무료, 개인회원 유료
The rate constants of hydrolysis of N-tert-butyl-α-phenylnitrone and its derivatives have been determined by UV spectrophotometry at 25℃ and a rate equation which can be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the hydrolysis products obtained and general base and substituent effects, plausible mechanism of hydrolysis in various pH range have been proposed. Below pH 4.5, the hydrolysis was initiated by the protonation and followed by the addition of water to α-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxides ion to α-carbon. In the range of 4.5~10.0 the addition of water to nitrone was rate controlling step.
4,000원
2.
1998.06 구독 인증기관 무료, 개인회원 유료
All the surface activities including surface tension, foaming power, foam stability, emulsifying power, dispersion effect, and detergency were measured and critical micelle concentration(cmc) was evaluated in dilute aqueous solution. The cmc evaluated by the Ring method was 10-3~10-4mol/L in case of monoesters, and 10-3~5.0×10-5mol/L in case of diesters, respectively. Surface tension of the aqueous solution was decreased to 45~50dyne/cm, showing the tendency that the ability of lowering the surface tension was dependent on increasing of carbon atom number in alkyl chain. Foaming power of all the monoesters was better than that of diesters. while foam stability of diesters was to the contrary. Emulsifying power of soybean oil or benzene was specially expected to be good for emulsifiers in industrial application fields. HLB values of monoesters and diesters evaluated by Griffin's method were in the range of 8 to 12. Dispersion property of ferric oxide was stable in the range of 4.5×10-5~5.0×-4mol/L in case of monoesters, and 10-5~10-4mol/L in case of diesters.
4,600원
3.
1998.06 구독 인증기관 무료, 개인회원 유료
The emulsion stability of W/O emulsion prepared by D phase emulsification during storage and handling is studied by using phase diagrams. The process of D phase emulsification begins with the formation of isotropic surfactant solution, followed by formation of oil-in-surfactant (O/D) gel emulsion by dispersion of octamethylcyclotetrasiloxane(OMCS) in the surfactant solution. Polyols were essential components for this purpose. To understand the function of polyols, the solution behavior of nonionic surfactant/oil/water/polyol systems were investigated by the ternary phase diagrams of polyoxyethylene oleyl ether/OMCS/propylene glycol(PG) aqueous solutions. The addition of PG increased the solubility of oil in the isotropic surfactant phase. D phase emulsification method has been applied to a new type of cosmetics. By using this emulsification technique, O/W emulsion were formed without a need for adjust of HLB. Fine and stable W/O emulsions were prepared by D phase emulsion.
4,000원
4.
1998.06 구독 인증기관 무료, 개인회원 유료
Displacement current measuring technique has been applied on the study of monolayers of functional polyimide containing azobenzene derivatives. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about 70a2 and 100a2. Displacement currents were investigated in connection with monolayer of long chain alkylamines. It was found that the maximum of displacement current appeared at the molecular area just before the initial rise of surface pressure in compression cycles of polyamic acid and long chain alkylamines.
4,000원
5.
1998.06 구독 인증기관 무료, 개인회원 유료
The catalytic oxidations of several cycloolefins in CH2Cl2 were been investigated using Mn(III)-, Fe(III)-porphyrin complexes as a catalyst and sodium hypochlorite as a terminal oxidant. Porphyrins were (p-CH3O)TTP, (p-CH3)TTP, TPP, (p-F)TPP, (p-Cl)TPP and (F20)TPP (TPP = tetraphenylporphyrin), and olefins were cyclopentene, cyclohexene and cycloheptene. The substrate conversion yield was discussed according to the substituent effects of metalloporphyrin. The conversion yield of substrate by changing the substituent of TPP increased in the order of p-CH3O 〈 p-CH3 〈 H 〈 p-F 〈 p-Cl, which was consistent with the sequence of 4Σ values of TPP. The conversion of cycloalkene followed the order of C5 < C6 < C7.
4,000원
6.
1998.06 구독 인증기관 무료, 개인회원 유료
This study is to develop a new synthetic method for the nitroarenes via non-electrophilic substitution. Direct nitration at the C-1 position of isoquinoline has never been reported and substitution in isoquinoline under the normal nitration condition occurs at C-5 and C-8. We have demonstrated a facile one-step sythetic method for the nitration of isoquinolines at the C-1 position, which involves the electrophilic attack of a DMSO-Ac2O complex, followed by nucleophilic addition of nitrate ion to this intermediate. Since the reaction is simple and mild, this method has preparative merit since 1-nitroisoquinolines are not readily accessible by other methods. Application to the synthesis of poly nitroarenes from the corresponding anilines was also described.
4,000원
7.
1998.06 구독 인증기관 무료, 개인회원 유료
Two-packaged polyurethane coatings were prepared by blending benzoic acid lactone modified polyester polyol(BLMPs) and HDI-biuret. BLMPs were synthesized by polycondensation of benzoic acid, viscosity depression component, with 1,4-butanediol, adipic acid, and polycaprolactone polyol. Kinematic viscosity of BLMP was gradually decreased with increasing benzoic acid content in BLMP. The low viscosity of modified polyester has an advantage of making a high-solid content coatings. After the film was coated with the prepared polyurethane coatings and cured at room temperature, the various physical properties were measured. They showed good physical properties such as flexibility, impact resistance, cross hatch adhesion, yellowness index, and rust resistance. These advantages are the results of introducing polycaprolactone polyol.
4,000원
8.
1998.06 구독 인증기관 무료, 개인회원 유료
The Cuo-Magnetite and ZnO-Magnetite catalysts with various of Cuo and ZnO mole% for Carbon Dioxide decomposed reaction synthesized. The catalysts were reduced by H2 at 350℃ for 3 hours. The temperature was obtained by TGA and DSC experiments. The structures of catalysts were confirmed by X-ray diffraction experiment. The surface area of catalysts is 15~27 m2/g. The results of Carbon Dioxide decomposed ability was better H2-reduced magnetite catalysts with 0.03 mole% CuO and 0.03 mole% ZnO than others catalysts. After Carbon Dioxide decomposed reaction, catalysts were reacted H2 and created only methane.
4,000원
9.
1998.06 구독 인증기관 무료, 개인회원 유료
Surface active properties of these aqueous Gemini surfactant solutions including surface tension, critical micelle concentration(cmc), foaming power, foam stability, emulsifying power and Krafft point were measured at given conditions. They showed excellent properties, being compared with conventional single-chain surfactants such as sodium dodecyl sulfonate(SDS). Their surface tensions in the aqueous solutions were decreased to 30~38 mN/m, which is lower than 39 mN/m of SDS, and their cmc values evaluated by surface tension method were 2.8×10-5~3.3×10-4 mol/L. These values were also much lower than that of SDS, 9.8×10-3 mol/L. The foaming power and foam stability, especially decyl and dodecyl compounds, were good and the emulsifying power in benzene or soybean oil was also excellent. All of the synthesized Gemini surfactants possessed good water solubility and their Krafft points were all below 0℃. As results, DDED and DDOD, Gemini surfactants which were synthesized are expected to be applied as foamers, emulsifiers and so on.
4,000원
10.
1998.06 구독 인증기관 무료, 개인회원 유료
α-sulfonated fatty acid polyethylene glycol esters with polyethylene oxide(addition, 3, 5, 10mol) were synthesized through esterification of α-sulfonated fatty acid methyl esters with alkyl chain length C12~C18. Their compounds were separated with column chromatography, and confirmed by TLC. Quantitative analysis of all the sulfonates were performed according to JIS K-3362 method, and ethylene oxide unit number were determined by ISO 2270 method. Structural properties of α-sulfonated fatty acid methyl esters and their derivatives were also identified from IR, and 1H NMR spectra.
4,000원
11.
1998.06 구독 인증기관 무료, 개인회원 유료
2-phenyl-N-methyl-1,3-thiazolium perchlorate(PTP)derivatives were synthesized via addition and substitution reactions. PTP was hydrolyzed under aqueous hydrochloride. The structures of the compounds were conformed by N.M.R.,I.R., and elemental analysis.
4,000원