The hydrolysis kinetics of atrazine in distilled water and leaching water from soil, and they influence factors were studied by incubation at 35degreesC and HPLC analysis method. The kinetic process of atrazine hydrol...The hydrolysis kinetics of atrazine in distilled water and leaching water from soil, and they influence factors were studied by incubation at 35degreesC and HPLC analysis method. The kinetic process of atrazine hydrolysis can be described by the first-order reaction law. The results showed that the hydrolysis rate constants k in leaching water and distilled water were 1.606 x 10(-3)/d and 1.055 x 10(-3)/d, respectively; the half-life of atrazine hydrolysis in distilled water at pH 3, pH 4.5 and pH 8 were 373 days, 522 days and 657 days respectively. The results also showed that the proton in reaction solution can catalyze the atrazine hydrolysis; humic acid and NH4+ etc. substances in aqueous solution can facilitate atrazine hydrolysis; rate constants of atrazine hydrolysis with humic acid and NH4NO3 were 2.431 X 10(-3)/d and 1.498 X 10(-3)/d respectively which were 2.3 and 1.42 times of control(1.055 X 10(-3)/d); anion NO3- can inhibit catalysis of humic acid to atrazine hydrolysis.展开更多
The kinetics of hydrolysis of cationic reactive disperse dyes containing quaternary group and chemical shift(13CNMR) of the adjacent carbon atoms with pyridine-acetylamino were discussed. The results show pyridine-a...The kinetics of hydrolysis of cationic reactive disperse dyes containing quaternary group and chemical shift(13CNMR) of the adjacent carbon atoms with pyridine-acetylamino were discussed. The results show pyridine-acetylamino reactive group had higher reactivity than chloroacetylamino and chemical shift(13 CNMR) of the adjacent carbon atoms with pyridine-acetylamino moved 18.77 ppm.展开更多
The productivity and efficiency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this stud...The productivity and efficiency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this study will find out how the pH and the amount of acetate influence the enzymatic hydrolysis of cellulose. The effects of pH and acetate on cellulase produced from Bacillus coagulans were studied at various pH 5-8, and acetate concentrations (0-60 mmol/L). A batch kinetic model for enzymatic cellulose hydrolysis was constructed from experimental data and performed. The base hypothesis was as follows: the rates of enzymatic cellulose hydrolysis rely on pH and acetate concentration. The results showed that the suitable pH range for cellulase production and cellulose hydrolysis (represents efficiency of cellulase) was 2.6-7.5, and 5.3-8.3, respectively. Moreover, acetate in the culture medium had an effect on cellulase production (KI = 49.50 mmol/L, n = 1.7) less than cellulose hydrolysis (/('i = 37.85 mmol/L, n = 2.0). The results indicated that both the pH of suspension and acidogenic products influence the enzymatic hydrolysis of cellulose in an anaerobic environment. To enhance the cellulose hydrolysis rate, the accumulated acetate concentration should be lower than 25 mmol/L, and pH should be maintained at 7.展开更多
Factors influencing dehydration of xylose to furfural,such as catalyst and extract agents,were investigated.Results indicated that high-temperature water may substitute for solid and liquid acid as a catalyst,and ethy...Factors influencing dehydration of xylose to furfural,such as catalyst and extract agents,were investigated.Results indicated that high-temperature water may substitute for solid and liquid acid as a catalyst,and ethyl butyrate improved furfural yield for the high distribution coefficient.A furfural yield of 75 % was obtained at200 °C for 3 h in ethyl butyrate/water.The reaction kinetics of xylose dehydration to furfural was investigated and it was found that the reaction order was 0.5,and the activation energy was 68.5 k J/mol.The rate constant k showed a clear agreement with the Arrhenius law from160 to 200 °C.展开更多
Acid hydrolysis mechanisms of orientin-2"-O-galactopyranoside(OGA),orientin and other flavone C-glycosides in the trollflowers[Trollius chinensis Bunge) were studied in this report for the first time.Hydrolysis pa...Acid hydrolysis mechanisms of orientin-2"-O-galactopyranoside(OGA),orientin and other flavone C-glycosides in the trollflowers[Trollius chinensis Bunge) were studied in this report for the first time.Hydrolysis parameters including temperature,acidity,solvent and reaction time were comprehensively investigated.OGA could be hydrolyzed to orientin,followed by an isomerization to isoorientin via a reversible Wessely-Moser rearrangement reaction under stronger acidic conditions.A first-order kinetic model fitted the hydrolysis process of OGA well.Under the optimal hydrolysis conditions of 80 ℃,1.0 mol/L H^+ and 7 h reaction time,about 77%OGA was transformed to orientin with no detectable isoorientin.These results could be helpful for better understanding of the acid hydrolysis kinetics of flavone C-glycosides,as well as the preparation of these valuable components under controlled acid hydrolysis conditions.展开更多
The hydrolysis reactions of N-(O,O'diisopropyl)phosphoryl-L-α-alanine (DIPP-L-α-Ala), N-(O,O'diisopropyl)- phosphoryl-D-α-alanine (DIPP-D-α-Ala), N-(O,O'-diisopropyl)phosphoryl-β-alanine (DIPP-β-Al...The hydrolysis reactions of N-(O,O'diisopropyl)phosphoryl-L-α-alanine (DIPP-L-α-Ala), N-(O,O'diisopropyl)- phosphoryl-D-α-alanine (DIPP-D-α-Ala), N-(O,O'-diisopropyl)phosphoryl-β-alanine (DIPP-β-Ala) and N-(O,O'-diisopropyl)phosphoryl-γ-amino butyric acid (DIPP-γ-Aba), were studied by HPLC and their hydrolysis reaction kinetic equations were obtained. Under acid conditions, the reaction rate of DIPP-L-α-Ala was close to that of DIPP-D-α-Ala and the same rule was true between DIPP-β-Ala and DIPP-γ-Aba. Meantime, the reaction rate of DIPP-L/D-α-Ala was as 10 times as that of DIPP-β-Ala or DIPP-γ-Aba. Under basic conditions, the hydrolysis reactions of DIPP-β-Ala and DIPP-γ-Aba almost did not take place and the reaction rate of DIPP-L/D-α-Ala was about 1/10 of that under acid conditions. Moreover, theoretical calculation further illuminated the differences of the hydrolysis rate from the view of energy. The results would provide some helpful clues to why nature chose a-amino acids but not other kinds of analogs as protein backbones.展开更多
β-FeOOH nanorods of 40 nm wide and 450 nm long were fabricated through precisely regulating the hydrolysis kinetics of Fe3+ in polyethylene glycol and the concentration of C1- as the structure-directing agent. Detai...β-FeOOH nanorods of 40 nm wide and 450 nm long were fabricated through precisely regulating the hydrolysis kinetics of Fe3+ in polyethylene glycol and the concentration of C1- as the structure-directing agent. Detailed structural and chemical analyses of the intermediates during the synthesis identified that the strong interaction between PEG and Fe3+ modulated the hydrolysis kinetics of Fe3+and prevented the aggregation of β-FeOOH nanorods; while C1- provided sufficient nucleation sites, stabilized the hollow channel of β-FeOOH, and more importantly induced the growth of the nanorods along [001] direction.展开更多
基金the National Natural Science Foundation of China(No.29777026)the Major Project Foundation of the Chinese Academy of Sciences(KZ951-B1-209-01)
文摘The hydrolysis kinetics of atrazine in distilled water and leaching water from soil, and they influence factors were studied by incubation at 35degreesC and HPLC analysis method. The kinetic process of atrazine hydrolysis can be described by the first-order reaction law. The results showed that the hydrolysis rate constants k in leaching water and distilled water were 1.606 x 10(-3)/d and 1.055 x 10(-3)/d, respectively; the half-life of atrazine hydrolysis in distilled water at pH 3, pH 4.5 and pH 8 were 373 days, 522 days and 657 days respectively. The results also showed that the proton in reaction solution can catalyze the atrazine hydrolysis; humic acid and NH4+ etc. substances in aqueous solution can facilitate atrazine hydrolysis; rate constants of atrazine hydrolysis with humic acid and NH4NO3 were 2.431 X 10(-3)/d and 1.498 X 10(-3)/d respectively which were 2.3 and 1.42 times of control(1.055 X 10(-3)/d); anion NO3- can inhibit catalysis of humic acid to atrazine hydrolysis.
文摘The kinetics of hydrolysis of cationic reactive disperse dyes containing quaternary group and chemical shift(13CNMR) of the adjacent carbon atoms with pyridine-acetylamino were discussed. The results show pyridine-acetylamino reactive group had higher reactivity than chloroacetylamino and chemical shift(13 CNMR) of the adjacent carbon atoms with pyridine-acetylamino moved 18.77 ppm.
基金supported by Thailand Graduate Insti- tute of Science and Technology (No. TGIST 01-46-12) National Science and Technology Development Agency, Thailand for Ph.D. Scholarship to Ms. Romsaiyud A, and National Research Council of Thailand for research grant under Fiscal Year 2007 Budget to King Mongkut's University of Technology Thonburi
文摘The productivity and efficiency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this study will find out how the pH and the amount of acetate influence the enzymatic hydrolysis of cellulose. The effects of pH and acetate on cellulase produced from Bacillus coagulans were studied at various pH 5-8, and acetate concentrations (0-60 mmol/L). A batch kinetic model for enzymatic cellulose hydrolysis was constructed from experimental data and performed. The base hypothesis was as follows: the rates of enzymatic cellulose hydrolysis rely on pH and acetate concentration. The results showed that the suitable pH range for cellulase production and cellulose hydrolysis (represents efficiency of cellulase) was 2.6-7.5, and 5.3-8.3, respectively. Moreover, acetate in the culture medium had an effect on cellulase production (KI = 49.50 mmol/L, n = 1.7) less than cellulose hydrolysis (/('i = 37.85 mmol/L, n = 2.0). The results indicated that both the pH of suspension and acidogenic products influence the enzymatic hydrolysis of cellulose in an anaerobic environment. To enhance the cellulose hydrolysis rate, the accumulated acetate concentration should be lower than 25 mmol/L, and pH should be maintained at 7.
基金supported by the National Natural Science Foundation of China (No.21376136,No.21176142,No.21376140,No.21176142,and No.21466001)Program for Changjiang Scholars and Innovative Research Team in University (IRT13026)
文摘Factors influencing dehydration of xylose to furfural,such as catalyst and extract agents,were investigated.Results indicated that high-temperature water may substitute for solid and liquid acid as a catalyst,and ethyl butyrate improved furfural yield for the high distribution coefficient.A furfural yield of 75 % was obtained at200 °C for 3 h in ethyl butyrate/water.The reaction kinetics of xylose dehydration to furfural was investigated and it was found that the reaction order was 0.5,and the activation energy was 68.5 k J/mol.The rate constant k showed a clear agreement with the Arrhenius law from160 to 200 °C.
基金supported by National Natural Science Foundation of China(No.81274190)Jiangsu Provincial Science and Technology Commission(No.BE2012649)Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Acid hydrolysis mechanisms of orientin-2"-O-galactopyranoside(OGA),orientin and other flavone C-glycosides in the trollflowers[Trollius chinensis Bunge) were studied in this report for the first time.Hydrolysis parameters including temperature,acidity,solvent and reaction time were comprehensively investigated.OGA could be hydrolyzed to orientin,followed by an isomerization to isoorientin via a reversible Wessely-Moser rearrangement reaction under stronger acidic conditions.A first-order kinetic model fitted the hydrolysis process of OGA well.Under the optimal hydrolysis conditions of 80 ℃,1.0 mol/L H^+ and 7 h reaction time,about 77%OGA was transformed to orientin with no detectable isoorientin.These results could be helpful for better understanding of the acid hydrolysis kinetics of flavone C-glycosides,as well as the preparation of these valuable components under controlled acid hydrolysis conditions.
基金Project supported by the National Natural Science Foundation of China (Nos. 20572061, 20672104).
文摘The hydrolysis reactions of N-(O,O'diisopropyl)phosphoryl-L-α-alanine (DIPP-L-α-Ala), N-(O,O'diisopropyl)- phosphoryl-D-α-alanine (DIPP-D-α-Ala), N-(O,O'-diisopropyl)phosphoryl-β-alanine (DIPP-β-Ala) and N-(O,O'-diisopropyl)phosphoryl-γ-amino butyric acid (DIPP-γ-Aba), were studied by HPLC and their hydrolysis reaction kinetic equations were obtained. Under acid conditions, the reaction rate of DIPP-L-α-Ala was close to that of DIPP-D-α-Ala and the same rule was true between DIPP-β-Ala and DIPP-γ-Aba. Meantime, the reaction rate of DIPP-L/D-α-Ala was as 10 times as that of DIPP-β-Ala or DIPP-γ-Aba. Under basic conditions, the hydrolysis reactions of DIPP-β-Ala and DIPP-γ-Aba almost did not take place and the reaction rate of DIPP-L/D-α-Ala was about 1/10 of that under acid conditions. Moreover, theoretical calculation further illuminated the differences of the hydrolysis rate from the view of energy. The results would provide some helpful clues to why nature chose a-amino acids but not other kinds of analogs as protein backbones.
基金supported by the National Natural Science Foundation of China (21025312, 21303193, 21321002)the National Key Basic Research Program of China (2013CB933100)
文摘β-FeOOH nanorods of 40 nm wide and 450 nm long were fabricated through precisely regulating the hydrolysis kinetics of Fe3+ in polyethylene glycol and the concentration of C1- as the structure-directing agent. Detailed structural and chemical analyses of the intermediates during the synthesis identified that the strong interaction between PEG and Fe3+ modulated the hydrolysis kinetics of Fe3+and prevented the aggregation of β-FeOOH nanorods; while C1- provided sufficient nucleation sites, stabilized the hollow channel of β-FeOOH, and more importantly induced the growth of the nanorods along [001] direction.