• KSBB Journal
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• v.8 no.4
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• pp.358-363
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• 1993

The effect of ultrasound on the acid hydrolysis of inulin was studied under significantly mild reaction conditions, at which sugar degradation products were not detected. Reaction conditions were i the range of 50~$60^{\circ}C$ and 0.1~0.3%(w/w) of HCl concentrations. The effects of reactor position inside water bath and mechanical agitation under ultrasound were investigated. The production rates of fructose with/without ultrasound irradiation were compared. The activation energies for both control and ultrasound reaction were the same, i. e., 25kca1/mo1, and ultrasound enhancement was average 22%.

• Journal of the Korean Chemical Society
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• v.34 no.1
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• pp.102-107
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• 1990

The reaction of thiazoline-azetidinone (7) with $I_2$ in $CH_2Cl_2-H_2O$ gave directly 3-iodo-3-methylcepham (4). A phase transfer catalyst considerably increased the reaction rate. Similar to the hydrolysis of thiazoline-azetidinone (7) under a weak acidic condition, thiazole (10) was given as major product in the treatment with 0.1 eq. of iodine. The difference between cyclization reaction and hydrolysis could be explained in terms of solvents, the amount of iodine and the nature of thiazoline-azetidinones (7).

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.20-27
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• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• New & Renewable Energy
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• v.9 no.2
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• pp.5-14
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• 2013

The efficiency of microwave-assisted acid hydrolysis of seaweeds for the production of ethanol was investigated and its effect on hydrolysis into reducing sugar and fermentation into ethanol evaluated as compared with those by conventional heating. A brown seaweed, Laminaria japonica (10-100g/L) was hydrolysed under dilute acidic condition (0.5N $H_2SO_4$, $100^{\circ}C$) with two sorts of heating: microwave irradiation for ${\leq}10min$ and conventional heating for 10-60min. Microwave-assisted hydrolysis was shown to be more efficient. A similar range of reducing sugar and ethanol yields as with the conventional autoclave heating procedure(${\geq}30min$) was observed, but it was obvious that production of ethanol from microwave-assisted hydrolysis had a 3 times faster reaction rate leading to very short production times, lower energy consumption/loss than from the conventional heating mode, and higher biomass loading without significant reducing ethanol yield, thus microwave-assisted acid hydrolysis is a potential alternative method for more effective hydrolysis of Laminaria japonica.

• Journal of the Korean Wood Science and Technology
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• v.20 no.2
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• pp.81-90
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• 1992

The effect of acid treatment of cellulose on the substitution charateristics of carboxymethylation was studied in this paper. Five samples of hydrocellulose(HC), all prepared from ${\alpha}$-cellulose by hydrolysis with five reaction times and determined on average molecular weight and polydispersity, were carboxymethylated to carboxymethyl cellulose (CMC). The CMCs from HCs were examined upon degree of substitution(DS), distribution of carboxymethyl groups in anhydroglucose units of the cellulose, and unsubstituted anhydroglucose(USAG) content. The DS of CMCs increased with increasing the hydrolysis time except CMC from HC at 1 hour hydrolysis time. In carboxymethylation the availability of hydroxyl groups on anhydroglucose units in HCs was the highest on OH(2), and the relative availability of OH(6) increased with the increasing of the hydrolysis time. The USAG contents were more deviated than that calculated based on Spurlin's model, and had a strong tendency of decreasing with increasing the hydrolysis time. The reactivity of HC was lower than that of ${\alpha}$-cellulose and the relative availability of OH(6) in HC increased with the hydrolysis time.

• Journal of the Korean Ceramic Society
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• v.41 no.4
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• pp.289-296
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• 2004

Whisker and short rod shaped hydroxyapatite (Ca$_{10}$(PO$_4$)$_{6}$(OH)$_2$ with stoichiometric composition (Ca/P=1.62 -1.67, molar ratio) has been synthesized by hydrolysis and hydrothermal reaction of aqueous $\alpha$-Ca$_3$(PO$_4$)$_2$($\alpha$-TCP) solution (pH 11), respectively. The shape of resultant HAp was mainly dependent on synthetic route and the microstructural development was on processing condition. In hydrolysis processing, the degree of intersection of whiskerlike particles and agglomeration in the apsis line increased with increasing reaction time. In hydrothermal synthesis, the reaction product obtained under excessive reaction time ($\geq$3 h at 20$0^{\circ}C$) was severely agglomerated without further grain growth above certain critical size (0.75 ${\mu}{\textrm}{m}$ in length, 0.3${\mu}{\textrm}{m}$ 11m in diameter).

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.260-267
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• 1990

The mechanism of enzymatic hydrolysis of raw corn starch by the purified glucoamylase and a - amylase in an agitated bead reaction system was studied by investigating the changes of sugar profiles produced by each enzyme, the granular structure of raw corn starch, the amount of enzyme adsorption on residual starch, and the amylose content in residual raw starch. The sugar profiles produced by the action of exo-type glucoamylase or endo-type $\alpha$ -amylase in an agitated bead system were not recognizably differed with those produced in reaction system without bead. Without enzyme the intergenic microcrystalline structure of starch granule was not changed by the simple mechanical impact of solid media, but it was cleaved. However, starch granule was fragment into large number of small particles by the synergistic action of enzyme and attrition-milling media, identified to be the major saccharification enhancing mechanism along with the increased amount of enzyme adsorption. The amylose content decreased more readily in an agitated bead reaction system, especially by $\alpha$ -amylase.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.588-593
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• 2022

The effects of P₂O₅-doped on the surface of MgO particles on hydrolysis, water repellency, and insulation behavior were investigated. P₂O₅-doped MgO has exhibited a unique electrical property, which is significant insulation behavior due to both the suppression of the hydrolysis reaction by P₂O₅ and water repellency. Therefore, the insulation behavior was inversely proportional to the hydrophilicity and the Mg(OH)₂ and OH^-charge transfer ratio by the surface hydration reaction of MgO. The insulation of MgO according to aging was strongly influenced by the surface hydration reaction, the band gap of the added dopant species, and the hydrophilicity and hydrophobicity of the dopant. Finally, it was to show electrical insulation by inhibiting the surface hydration reaction of the hydrophilic MgO, which has a great potential for use in heat transfer medium applications.

• Journal of the Korean Chemical Society
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• v.20 no.1
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• pp.48-55
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• 1976

The rate constants of the derivatives of N-(2,4-dinitrophenyl)-benzimidoyl chloride were determined at various pH and a rate equation which can be applied over wide pH range was obtained. The reaction mechanism of hydrolysis of N-(2,4-dinitrophenyl)-benzimidoyl chloride which has not been studied carefully earlier in acidic and basic solution can be fullly explained by the rate equation obtained. The rate equation reveals that, beow pH 7.00, the hydrolysis of benzimidoyl chloride proceeds through $S_N2$ reaction to form a carbonium ion intermediate.Above pH 8.5, however, the hydrolysis proceeds through the $S_N2$ type reaction which depends on hydroxide ion and imidoyl chloride concentration. At pH 7.0∼8.5, two reactions occur competitively.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.138-143
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• 1997

Acid-catalyzed hydrolysis of 3,3-bis(methylthio)-2-propen-1-phenyl-1-one derivatives were studied kinetically in concentrated aqueous hydroperchloric acid(-Ho < 2.23) at $30^{\circ}C.$ The substituent effect, analysis of hydrolysis product, hydration $parameter({\omega} & {\phi}$) from the Bunnett equation and the Bunnett-Olsen equation on the rate indicate that the acid-catalyzed hydrolysis of the substrates below 3.8 M hydroperchloric acid media occurs through A-1 type reaction($3.3 >{\omega},\;0.58 >{\phi} & {\rho}< 0$) mechanism and above 3.8 M hydroperchloric acid, the reaction proceeds A-2 type reaction($0 <(\omega)$, $0 <{\phi} & (\rho)> 0$) mechanism.