• Title/Summary/Keyword: hydrolysis

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Overview of Hydrolysis : A Review Part I- Hydrolysis Mechanism

  • Kim, Kwang-Jea
    • Elastomers and Composites
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    • v.55 no.2
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    • pp.128-136
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    • 2020
  • The hydrolysis mechanisms as well as the hydrolysis measurement technique and its practical applications in material manufacturing fields are revised. This chapter, Part 1, elaborates the theoretical aspects of the hydrolysis mechanism. Acid-catalyzed and base-catalyzed hydrolysis mechanisms are reviewed. The quantitative analysis method based on the SIM technique using py-GC-MS is reviewed. Examples of hydrolysis of alkoxysilane in elastomer composites currently used in the industry and hydrolysis of amine in plastic composites are shown. Moreover, Part 2 discusses the mechanical property changes in elastomer and plastic composites after hydrolysis.

Single Hydrolysis Method for the Amino Acid Determination in Foods and Composite Dishes (식품의 아미노산 정량을 위한 단일가수분해 방법의 개발)

  • 박내선
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.3
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    • pp.422-429
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    • 1997
  • For the complete and accurate amino acid determination of protein and food samples, 3 different hydrolysis procedures have been conducted in parallel for each sample, which include the alkaline hydrolysis for tryptophan determination, performic acid oxidation prior to the acid hydrolysis for the determination of cysteine and cystine, and the 6N HCl hydrolysis for the determination of the rest of amino acids. In the present study, amino acid concentrations obtained from the modified single hydrolysis procedure were compared with the values from the conventional hydrolysis procedures in casein and nine food and composite dish samples. In most of the samples tested, the modified single hydrolysis procedure gave significantly higher values of cysteins and cystein compared to the performic acid oxidation method, but resulted in a considerable destruction of tryptophan in food and composited dish samples. There was no consistent difference in the rest of amino acid concentrations between the two hydrolysis systems. Therefore, for complete amino acid determination of various foods and composite dishes, the single hydrolysis method may replace the 6N HCl hydrolysis and performic acid oxidation methods, and thereby reduces 3 hydrolyses to 2 steps with much higher recoveries of the sulfur containing amino acids.

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A Study of Biological Hydrolysis Efficiency for Methane Digestion with Municipal Solid Waste (메탄발효를 위한 도시쓰레기 초고온 가용화 방법의 효율성 검토)

  • Cheon, Ji-Hoon;Hiroshi, Tsuno
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.561-572
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    • 2010
  • The efficiency of biological hydrolysis at $80^{\circ}C$ on municipal solid waste mixed with anaerobic digestion sludge was investigated in 100L batch reactors. The hydrolysis effect was observed within a day, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, and the effect was observed during two days, When the reactor used for post-treatment reactor. For both configurations, methane production rate decreased, when hydrolysis was carried out more than a day. Gaseous ammonia in the hydrolysis reactors was successtully removed by the ammonia stripping system. Microbial diversity analysis on the hydrolysis reactors indicated dependency of microbial diversity on the configuration of the hydrolysis reactors. Carbohydrate and lactate degrading microbes dominated in the hydrolysis reactor, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, while protein degrading microbes dominated in the post-treatment reactor.

Microwave-assisted Weak Acid Hydrolysis of Proteins

  • Seo, Mi-Yeong;Kim, Jin-Hee;Park, Se-Hwan;Lee, Ji-Hye;Kim, Tae-Hee;Lee, Ji-Hyeon;Kim, Jeong-Kwon
    • Mass Spectrometry Letters
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    • v.3 no.2
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    • pp.47-49
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    • 2012
  • Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at $37^{\circ}C$, $50^{\circ}C$, and $100^{\circ}C$ for 1 h. The most effective hydrolysis was observed at $100^{\circ}C$. Hydrolysis products were investigated using matrixassisted laser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini of aspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60- min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at $100^{\circ}C$. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteins and that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.

Overview of Hydrolysis : A Review Part II- Hydrolysis Application

  • Kim, Kwang-Jea
    • Elastomers and Composites
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    • v.55 no.2
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    • pp.137-146
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    • 2020
  • Part 1 provides a theoretical introduction of the hydrolysis mechanism, while Part 2 introduces other types of reaction mechanisms after hydrolysis in elastomer and PA66 composites. We reviewed the condensation reaction, which occurs after hydrolysis in bi-functional alkoxy silane (TESPD & TESPT), and investigated its effects on the mechanical properties of the composites. We also reviewed activators such as zinc soap, which enhances the mechanical properties of silica-silane-filled elastomer composites. The interaction parameter of silica-silane-filled elastomer composites [αC (alpha C)] were also discussed. The effects of hydrolysis on the mechanical property changes in plastic composites were compared and reviewed.

Angiotensin I Converting Enzyme Inhibitory Activity of Krill (Euphausia superba) Hydrolysate

  • Kim Dong-Soo;Park Douck-Choun;Do Jeong-Ryong
    • Fisheries and Aquatic Sciences
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    • v.5 no.1
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    • pp.21-27
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    • 2002
  • Angiotensin I converting enzyme inhibitory activities of shelled krill (Euphausia superba) hydrolysates by autolysis and by hydrolysis with commercial proteases were analyzed. Among the proteases, Alcalase was the most effective protease for the hydrolysis of krill considering the degree of hydrolysis $(87.5\%)$ and the ACE inhibitory activity $(60\%)$. Four hour hydrolysis suggested as the most suitable and economic. In order to establish the optimum hydrolysis condition of krill, degree of hydrolysis and ACE inhibitory activity as affected by Alcalase concentration and water amount added were statistically analyzed by response surface methodology (RSM). The optimum hydrolysis condition was $2.0\%$ Alcalase hydrolysis in 2 volumes (v/w) of water at $55\% for 4 hr. The hydrolysate prepared from the optimum hydrolysis condition was fractionated by molecular weight. The lower molecular weight fraction showed the higher ACE inhibitory activity. $IC_{50}$ of the fraction under 500 Da was 0.57mg protein/mL.

Hydrolysis of the Ester Crosslinking on Cotton Fabric Treated with Polycarboxylic Acid(I) (polycarboxylic acid 처리면포의 Ester 가교결합의 가수분해 (I))

  • 강인숙;배현숙
    • Textile Coloration and Finishing
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    • v.15 no.4
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    • pp.24-31
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    • 2003
  • In this research, we applied FT-IR spectroscopy to study the hydrolysis of the ester-crosslinking formed by various polycarboxylic acids on the cotton fabric. We observed the following; (1) the ester-crosslinking is less durable to hydrolysis than ether-crosslinking under all conditions; (2) the ester-crosslinking formed by polycarboxylic acids having more than three carboxyl groups, such as butanetetracarboxylic acid (BTCA), are substantially more durable to hydrolysis than the acids having two or three carboxyl groups, such as maleic and citric acid; (3) alkaline conditions drastically accelerate the hydrolysis of both urea- and ester-crosslinking; and (4) the ester-crosslinking formed by poly(maleic acid) is more resistant to hydrolysis at alkaline conditions than BTCA. (5) polycarboxylic acid molecules were removed from the fabric at same rate as the hydrolysis of the ester linkage. FT-IR spectroscopy has proved to be a useful analytical technique for evaluating the hydrolysis of the crosslinked cotton fabric.

Hydrolysis of the Ester Crosslink on Cotton Fabric Treated with Combination of Poly(maleic acid) and Citric Acid (Poly(maleic acid)/Citric Acid 혼합 처리면포의 Ester 가교결합의 가수분해)

  • Kang In-sook;Bae Hyun-sook
    • Textile Coloration and Finishing
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    • v.17 no.3
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    • pp.16-25
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    • 2005
  • In this research, we investigated hydrolysis of the ester crosslinking on cotton fabric treated with polymer of maleic acid(PMA), citric acid(CA) and combination of polymer of maleic acid and citric acid using Fourier transform infrared spectroscophy. The rate of hydrolysis of the ester crosslinkage increased with pH regardless of the type of polycarboxylic acid used and even after hydrolysis for 256 hour in pH 13_4 solution, the treated fabric retained $10-20\%$ ester crosslinkage. The durability to alkaline hydrolysis of the ester crosslinkage formed by CA was lower than that of by PMA and combination of poly(maleic acid) and citric acid indicating that the ester formed by CA on the cotton fabric is more susceptible to hydrolysis than that formed by PMA and combination of PMA and CA. The total amount of ester and polycarboxylic acid molecules removed from fabric increased with increasing hydrolysis time but the rate of hydrolysis of ester linkage were higher than that of removal of polycarboxylic acid molecule from the fabric. The characteristic of hydrolysis of fabric treated with combination of PMA and CA was related with the mixing ratio of PMA and CA in treating fabric.

High Char-Yield in AN-AM Copolymer by Acidic Hydrolysis of Homopolyacrylonitrile

  • Cheng, Run;Zhou, You;Wang, Jing;Cheng, Yumin;Ryu, Seungkon;Jin, Riguang
    • Carbon letters
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    • v.14 no.1
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    • pp.34-39
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    • 2013
  • Acrylonitrile (AN)-acrylamide (AM) copolymers were prepared by nitric acidic hydrolysis of homopolyacrylonitrile. The acrylamino group increased as a function of hydrolysis time, while crystallinity decreased. Differential scanning calorimetry and a thermal gravimetric analysis indicated that the acylamino introduced by acidic hydrolysis effectively enhanced the cyclization reaction at low temperature due to the change of the cyclization reaction mechanism. Char-yield of AN-AM copolymers also gradually increased with increasing hydrolysis time. The maximum char-yield was 49.48% when hydrolized at $23^{\circ}C$ in 65% nitric acid solution for 18 h, which was 30% higher than that of non-acidic hydrolysis of homopolyacrylonitrile. Simulation of the practical process also showed an increase of char yields, where the char yields were 55.43% and 62.60% for homopolyacrylonitrile and copolyacrylonitrile, respectively, with a hydrolysis time of 13 h.

Effectiveness of Enzymatic Hydrolysis on Polyamide Fabric

  • Kim, Hye Rim;Seo, Hye Young;Song, Ah Reum
    • Journal of the Korean Society of Clothing and Textiles
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    • v.37 no.7
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    • pp.962-971
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    • 2013
  • We compared the effectiveness of amidase (amano acylase, AA) and an endopeptidase, (trypsin, TR) in modifying the hydrophobicity of polyamide fabric. We evaluated the number of amino groups released into the reaction mixture in order to optimize the treatment conditions. We found that a large number of amino groups were released into the reaction mixture due to the cleavage of amide bonds by AA hydrolysis; however, the TR hydrolysis exhibited a relatively lower activity compared to AA hydrolysis. In AA and TR hydrolysis, significant differences were observed in the K/S values and moisture regain. Amide bonds in polyamide fabric were hydrolyzed by AA hydrolysis effectively. Compared to TR, AA formed more hydrolysis product (amino groups) on the fabric surface. Thus, the hydrophobicity of polyamide fabric was modified using AA hydrolysis (as verified by the wettability test) without any deterioration of fiber strength.