• Journal of the Korean Wood Science and Technology
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• v.41 no.1
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• pp.1-11
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• 2013

In this study, we investigated chemical characteristics of solid residues obtained from inorganic acid hydrolysis of hybrid poplar (Populus alba ${\times}$ glandulosa). Different concentration (72, 36, 18%) of sulfuric acid and hydrochloric acid were used for first hydrolysis step and second hydrolysis step were carried out after equally dilution to 4%. Solid residues after consecutive two step hydrolysis were named to RS72 (Residue from Sulfuric acid 72%), RS36, RS18, as well as RC36 (Residue from hydroChloric acid 36%) and RC18, respectively. The yield of RS decreased from 71.2% to 21.4% with increasing sulfuric acid concentration in the first hydrolysis step, whereas that of RC showed little difference (67.0% to 65.0%), irrespective of hydrochloric acid concentration. The lignin content in solid residue was 23.6% for both of RS36 and RS18, 25.6% for RC36 and 27.3% for RC18, respectively. The results of pyrolyzer-GC/MS showed that 24 cellulose derivatives (Levoglucosan, Furfural) and 21 lignin derivatives (Guaiacol, Syringol) were detected. Thermogravimetric analysis indicated that the yield of char increased and maximum wieght loss rate decreased with increasing lignin portion of solid residue. Therefore, structure of lignin was condensed effectively by sulfuric acid and by high concentration of acid.

• Mass Spectrometry Letters
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• v.10 no.3
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• pp.79-83
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• 2019

Horse heart myoglobin (MYG) and bovine serum albumin (BSA) were hydrolyzed by microwave-assisted weak-acid hydrolysis for 10, 20, 30, 40, 50, and 60 min using 2% formic acid (FA) at $100^{\circ}C$. Generally, the number of identified peptides increased with increasing irradiation time, indicating that the duration of microwave irradiation is linked to the efficiency of hydrolysis. For MYG, irradiation for 60 min provided the highest number of identified peptides, the greatest sequence coverage values and the highest MASCOT score values among the investigated irradiation times. Irradiation of BSA for 50 min, however, yielded a greater number of peptides than irradiation for 60 min due to the generation of miscleaved peptides after microwave irradiation for 50 min.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.542-546
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• 2018

In this study, the effects of malonic acid-catalyzed pretreatment on the subsequent enzymatic hydrolysis of red macro-algae Gracilaria verrucosa for production of biosugar (total reducing sugar) were investigated. In the hydrothermal pretreatment condition of 300 mM malonic acid, 1:20 solid-to-liquid ratio at $130^{\circ}C$ for 60 min, a 49.2% biosugar yield was achieved. Moreover, by subsequent enzymatic hydrolysis after pretreatment, maximum yield of 64.5% was achieved.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.73-81
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• 1999

Four bis-iodosobenzoic acid derivatives have been synthesizd in 5 steps following literature methods from 5-hydroxyantranilic acid; 1) diazotization and iodination, 2) acid protection, 3) tosylate substitution, 4) acid deprotection, 5) oxidation of iodo-substituent to iodoso group. Catalytic effects of new 5,5'-tri-, tetra-, deca-, polyethyleneglycoxy- bis(2-iodosobenzoic acid) on hydrolysis reactions of PNPDPP(p-nitrophenyl diphenyl phosphate), sarin and soman have been measured to determine the role of ethyleneglycoxy substituents as phase transfer catalysts. At $25{\pm}0.2^{\circ}C$, pH 8.0, and cetyltrimethyl ammonium chloride(CTACl) micelle solution condition, bis-IBA derivatives hydrolyzes PNPDPP with maximum pseudo-first order rate constant($K_{obsd}^{max}$) of 0.32035 ~ 0.13659 $sec^{-1}$, which corresponds to 2~18 times rate increase than those of unsubstituted o-IBA[iodosobenzoate($K_{obsd}^{max}=0.0645sec^{-1}$), iodoxybenzoate ($K_{obsd}^{max}$ = $0.0178 sec^{-1}$)]. At the similar condition for PNPDPP hydrolysis, bis-IBA derivatives also act as efficient catalysts for hydrolytic cleavage of nerve agents such as sarin and soman. Hydrolysis rate constant with 5,5'-polyethyleneglycoxy- bis(2-iodosobenzoic acid) shows 7 times increase than that of simple 5-hydroxy-2-iodosobenzoic acid.

• Korea-Australia Rheology Journal
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• v.17 no.2
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• pp.79-85
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• 2005

Aqueous mixtures of hyaluronic acid and poly(vinyl alcohol) system and hydrogels thereof were introduced to obtain new bioartificial materials that have excellent mechanical properties, biocompatibility and enhanced rheological properties. The interactions between hyaluronic acid and poly(vinyl alcohol) and/or borax were investigated by rheological measurements. Preparation parameters of the aqueous mixtures were mixture composition, the degree of hydrolysis of poly(vinyl alcohol) and borax concentration. From the rheological behavior, it could be deduced that the key factor of the interaction between hyaluronic acid and poly(vinyl alcohol) was the hydrogen bonding between them and the effect was pronounced with borax. Enhanced viscosity was observed at the composition of $20wt\%$ of hyaluronic acid solution and $80wt\%$ of poly(vinyl alcohol) and borax solution. Rheological properties were influenced by the degree of hydrolysis of poly(vinyl alcohol) and borax concentration. As the degree of hydrolysis and borax concentration increased, rheological properties increased due to the increased hydrogen bonding and networking of hyaluronate aggregates. Physical hydrogels from hyaluronic acid and poly(vinyl alcohol) were prepared and the composition dependence of the gels was rheologically investigated as well.

• Journal of Surface Science and Engineering
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• v.53 no.3
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• pp.87-94
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• 2020

Herein, sulfonated carbon nanotubes (CNT) have been prepared in dilute sulfuric acid (H₂SO₄) via a novel sulfonation approach based on gas-liquid interfacial plasma (GLIP) at room temperature. The sulfonic acid groups and total acid groups densities of CNT after GLIP treatment in 2 M H₂SO₄ for 45 min can reach to 0.53 mmol/g and 3.64 mmol/g, which is higher than that of sulfonated CNT prepared under 0.5 M / 1 M H₂SO₄. The plasma sulfonated CNT has been applied as catalysts for the conversion of microcrystalline cellulose to glucose. The effect of hydrolysis temperature and hydrolysis time on the conversion rate and product distribution have been discussed. It demonstrates that the total conversion rate of cellulose increasing with hydrolysis temperature and hydrolysis time. Furthermore, the GLIP sulfonated CNT prepared in 2 M H₂SO₄ for 45 min has shown high catalytic stability of 85.73 % after three cycle use.

• Journal of the Korean Chemical Society
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• v.68 no.3
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• pp.139-145
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• 2024

This study aims to elucidate the mechanism involved in the hydrolysis of the hexacyanoferrate(III) complex ion (Fe(CN)₆^3-) and the mechanism leading to the formation of Prussian blue (Fe^III₄[Fe_II(CN)₆]₃·xH₂O, PB) in acidic aqueous solutions at moderately elevated temperatures. Hydrolysis constitutes a crucial step in generating PB through the widely used single-source or precursor method. Recent PB syntheses predominantly rely on the single-source method, where hexacyanoferrate(II/III) is the exclusive reactant, as opposed to the co-precipitation method employing bare metal ions and hexacyanometalate ions. Despite the widespread adoption of the single-source method, mechanistic exploration remains largely unexplored and speculative. Utilizing UV-vis spectrophotometry, negative-ion mode liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), and a devised reaction, this study identifies crucial intermediates, including aqueous Fe^2+/3+ ions and hydrocyanic acid (HCN) in the solution. These two intermediates eventually combine to form thermodynamically stable PB. The findings presented in this research significantly contribute to understanding the fundamental mechanism underlying the acid-catalyzed hydrolysis of the hexacyanoferrate(III) complex ion and the subsequent formation of PB, as proposed in the sequential mechanism introduced herein. This finding might contribute to the cost-effective synthesis of PB by incorporating diverse metal ions and potassium cyanide.

• Applied Biological Chemistry
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• v.27 no.1
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• pp.29-33
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• 1984

Chemical composition and condition of acid hydrolysis of waste composts during the cultivation of oyster mushroom (Pleurotus ostreatus) were determined. Ash content of composts increased while organic matter content decreased as the cultivation progressed. More than 90% of mushroom was produced from the first and second cropping period. An optimum condition for acid hydrolysis was at 2.0% $H_{2}SO_{4},\;1.5kg/cm^{2}$ vapor pressure for 30min and 20times (acid/compost). Formation of furfural in acid hydrolysis increased remarkably as acid concentration increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.4
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• pp.18-27
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• 1997

This study was performed to obtained the optimal delignified condition of exploded wood on the acid hydrolysis with sulfuric acid. Wood chips of pine wood(Pinus desiflora), oak wood(Quercus serrata) and birch wood (Betula platyphylla var. japonica) were treated with a high pressure steam (20-30kgf/$\textrm{cm}^2$, 2-6 minutes). The exploded wood was delignified with sodium hydroxide and sodium chlorite, and then hydrolyzed with sulfuric acid. The result can be summerized as follows ; In the exploded wood treated with sodium hydroxide, the optimal concentration of sodium hydroxide was 1% as content of lignin in the exploded wood. Lignin content of exploded wood treated with sodium chlorite was lower then that sodium hydroxide. The maximum reducing sugar yield of exploded wood treated with 1% sodium hydroxide was lower than non-treated exploded wood. In the case of sodium chlorite treated, the maximum reducing sugar yield was hgher than non-treated exploded wood. Sugar composition of acid hydrolysis solution was composed of xylose and glucose residue, and the rate of glucose residue was increased in high pressure condition.

• YAKHAK HOEJI
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• v.42 no.1
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• pp.39-45
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• 1998

Kojic acid, antimelanogenic agent, has been widely used in cosmetics to lighten the skin color. However, it has skin irritancy and instability against pH, temperature and light. To overcome these problems and optimize the molecular structure of kojic acid (KA), a prodrug, kojic acid monostearate(KMS), has been synthesized to modify the topical drug delivery in the point of sustained release of the parent drug via enzymatic hydrolysis during skin absorption. The prodrug was tested for enzymatic hydrolysis with cytosolic fraction of hairless mouse, skin. From the in vitro skin permeation study through hairless mouse skin, we found that KMS was retained in the skin and generated KA continuously by the skin esterase cleavage. In addition, topical formulations of o/w type creams and polyolprepolymer-containing cream were further tested for whitening effects using in vivo yellow skin guinea pig model.