The Pyrolysis Behavior of Alkali Lignin Oxygenized by Hydrogen Peroxide in Ionic Liquid 1-Butyl-3-Methylimidazolium Chloride ([BMIm]Cl)

2014 ◽  
Vol 598 ◽  
pp. 86-89
Author(s):  
Zhong Lian Yang ◽  
Ming Qiang Chen ◽  
Zhong Yi Luan ◽  
Wen Tao Zhang
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Ionic Liquid ◽  
Black Liquor ◽  
Mixed Solution ◽  
Alkali Lignin ◽  
Pyrolysis Reaction ◽  
First Order ◽  
Pyrolysis Behavior

In order to make better use of lignin, a mixed solution with isopyknic hydrogen peroxide 30% aqueous solution and an ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIm]Cl) was used to oxygenize alkali lignin from black liquor. The pyrolysis behavior of the treated alkali lignin (Regenerated ALG) was investigated via TGA. The kinetic controlling temperature range of the Regenerated ALG pyrolysis is between 533K and 649K approved by TG/DTG/DTA data, and the dominated pyrolysis is occurred below 574.7K, which was calculated from a kinetics model using Coats-Redfern method with a first order pyrolysis reaction. The activation energy of the Regenerated ALG also reached up to 105.675kJ/mol, which is 2.2 times greater than the non-treated one.

THE THERMAL DECOMPOSITION OF HYDROGEN PEROXIDE VAPOUR. II.

1947 ◽  
Vol 25b (2) ◽  
pp. 135-150 ◽  
Author(s):  
Paul A. Giguère
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Thermal Decomposition ◽  
Low Temperatures ◽  
Hydrocyanic Acid ◽  
Quartz Surface ◽  
First Order ◽  
Acid Washing ◽  
Reaction Vessels ◽  
Low Pressures

The decomposition of hydrogen peroxide vapour has been investigated at low pressures (5 to 6 mm.) in the temperature range 50° to 420 °C., for the purpose of determining the effect of the nature and treatment of the active surfaces. The reaction was followed in an all-glass apparatus and, except in one case, with one-litre round flasks as reaction vessels. Soft glass, Pyrex, quartz, and metallized surfaces variously treated were used. In most cases the decomposition was found to be mainly of the first order but the rates varied markedly from one vessel to another, even with vessels made of the same type of glass. On a quartz surface the decomposition was preceded by an induction period at low temperatures. Fusing the glass vessels slowed the reaction considerably and increased its apparent activation energy; this effect was destroyed by acid washing. Attempts to poison the surface with hydrocyanic acid gave no noticeable result. The marked importance of surface effects at all temperatures is considered as an indication that the reaction was predominantly heterogeneous under the prevailing conditions. Values ranging from 8 to 20 kcal. were found for the apparent energy of activation. It is concluded that the decomposition of hydrogen peroxide vapour is not very specific as far as the nature of the catalyst is concerned.

Comparison of the oxidative pyrolysis behaviors of black liquor solids, alkali lignin and enzymatic hydrolysis/mild acidolysis lignin

RSC Advances ◽  
2015 ◽  
Vol 5 (97) ◽  
pp. 79532-79537 ◽  
Author(s):  
Hao Cheng ◽  
Shubin Wu ◽  
Xiaohong Li
Keyword(s):  
Enzymatic Hydrolysis ◽  
Heating Rate ◽  
Black Liquor ◽  
Alkali Lignin ◽  
Pyrolysis Reaction ◽  
Oxidative Pyrolysis

The rough heating rate of the oxidative pyrolysis reaction can be measured, and it's about 720 °C min−1 at 600 °C.

THE NON-ENZYMATIC HYDROLYSIS OF ADENOSINE DIPHOSPHATE

1957 ◽  
Vol 35 (12) ◽  
pp. 1496-1503 ◽  
Author(s):  
K. A. Holbrook ◽  
Ludovic Ouellet
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Enzymatic Hydrolysis ◽  
Inorganic Phosphate ◽  
Adenosine Diphosphate ◽  
Hydrogen Ions ◽  
Kcal Mole ◽  
First Order ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of the non-enzymatic hydrolysis of adenosine diphosphate in aqueous solution have been studied at pH 3.5 to 10.5 and temperatures from 80° to 95 °C. The reaction has been followed by measuring colorimetrically the inorganic phosphate liberated according to the over-all reaction[Formula: see text]The reaction has been found to be first order with respect to ADP concentration and to be catalyzed by hydrogen ions. From rate studies at pH 8.0 an activation energy of 24.2 kcal./mole was derived. A mechanism is proposed to account for the observed facts and the mechanism for the hydrolysis of adenosine triphosphate is also discussed.

Epoxidation of Olefins Catalyzed by Polyoxomolybdates Formed in-situ in Ionic Liquids

2013 ◽  
Vol 68 (10) ◽  
pp. 1138-1142 ◽  
Author(s):  
Lilian R. Graser ◽  
Sophie Jürgens ◽  
Michael E. Wilhelm ◽  
Mirza Cokoja ◽  
Wolfgang A. Herrmann ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Ionic Liquid ◽  
Catalyst Concentration ◽  
Sodium Molybdate ◽  
Significant Loss ◽  
Catalytic Epoxidation ◽  
Epoxidation Reaction ◽  
Epoxidation Of Olefins

Polyoxomolybdates were generated in situ by treating a carboxylic acid-functionalized ionic liquid with an aqueous solution of sodium molybdate. This reaction mixture was applied in the catalytic epoxidation of olefins using hydrogen peroxide as oxidant. The influence of acid and catalyst concentration as well as of the reaction temperature was investigated. The system showed a good performance for the epoxidation reaction and can be reused several times without a significant loss of activity. We present an easy, cheap and environmentally friendly catalytic system for the epoxidation of cis-cyclooctene.

scholarly journals Temperature and pH effects on the kinetics of 2-aminophenol auto-oxidation in aqueous solution

2003 ◽  
Vol 1 (3) ◽  
pp. 233-241 ◽  
Author(s):  
Dumitru Oancea ◽  
Mihaela Puiu
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Aqueous Solution ◽  
Ph Effects ◽  
Influence Of Temperature ◽  
First Order ◽  
Incremental Methods ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetics Of

AbstractThe kinetics of the auto-oxidation of 2-aminophenol (OAP) to 2-amino-phenoxazin-3-one (APX) was followed in air-saturated aqueous solutions and the influence of temperature and pH on the auto-oxidation rate was studied. The kinetic analysis was based on a spectrophotometric method following the increase of the absorbance of APX. The process follows first order kinetics according to the rate law—d[OAP]/dt=k′[OAP]. The experimental data, within the pH range 4–9.85, were analyzed using both differential and incremental methods. The temperature variation of the overall rate constant was studied at pH=9.85 within the range 25–50°C and the corresponding activation energy was evaluated.

scholarly journals Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide catalyzed by copper oxide

2019 ◽  
Vol 80 (1) ◽  
pp. 126-133
Author(s):  
Hamza Amaouche ◽  
Salima Chergui ◽  
Farid Halet ◽  
Ahmed Réda Yeddou ◽  
Abdelmalek Chergui ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Copper Oxide ◽  
Copper Oxide Nanoparticles ◽  
Catalyst Stability ◽  
Molar Ratio ◽  
First Order ◽  
Cyanide Removal ◽  
Stability Kinetics ◽  
Kinetics Of

Abstract This work is dedicated to the removal of free cyanide from aqueous solution through oxidation with hydrogen peroxide H2O2 catalyzed by copper oxide nanoparticles. Effects of initial molar ratio [H2O2]0/[CN−]0, catalyst dose, temperature, pH and the catalyst stability on cyanide removal have been investigated. The use of copper oxide has improved the reaction rate showing catalytic activity. The cyanide removal efficiency was increased from 60% to 94% by increasing in the dose of catalyst from 0.5 g/L to 5.0 g/L. Increasing the temperature from 20 °C to 35 °C promotes cyanide removal and the four successive times re-use of catalyst shows good stability. Kinetics of cyanide removal was found to be of pseudo-first-order with respect to cyanide. The rate constants have been determined.

Kinetics and mechanism of the cytochrome c – sulfite reaction

1991 ◽  
Vol 56 (7) ◽  
pp. 1552-1559
Author(s):  
Joaquin F. Perez-Benito ◽  
Conchita Arias
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Cytochrome C ◽  
Apparent Activation Energy ◽  
Sodium Sulfite ◽  
Horse Heart Cytochrome ◽  
First Order ◽  
Cyt C ◽  
Ph Range ◽  
Horse Heart Cytochrome C

The reaction between the oxidized form of horse-heart cytochrome c and sodium sulfite in aqueous solution has been studied in the pH range 6.5 – 8.2. The reaction is first order in both oxidant and reductant, is accelerated by an increase in pH and is slowed down by addition of potassium chloride. An increase in pH results in an increase in the apparent activation energy (66-77kJ . mol-1). A mechanism in which both HSO3- and SO32- act as reducing agents is proposed, the activation energies corresponding to the cyt c-HSO3- and cyt c-SO32- reactions being 63 ± 4 and 79 ± 2 kJ mol-1, respectively.

SODIUM DITHIONITE, DECOMPOSITION IN AQUEOUS SOLUTION AND IN THE SOLID STATE

1959 ◽  
Vol 37 (9) ◽  
pp. 1567-1574 ◽  
Author(s):  
M. W. Lister ◽  
R. C. Garvie
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Ionic Strength ◽  
Solid State ◽  
Linear Growth ◽  
Sodium Dithionite ◽  
Order Reaction ◽  
First Order ◽  
Random Nucleation ◽  
Best Fit

The decomposition of sodium dithionite has been investigated in alkaline aqueous solution. Under these conditions it decomposes by a first order reaction with a rate constant of 4.5 × 10−4 min−1 at 88.5 °C and an activation energy of 26.5 kcal/g-molecule. The ionic strength, and the concentration of the sodium hydroxide also present, affect the rate to some extent. A possible mechanism is suggested. The decomposition of solid sodium dithionite was also examined, and was found to give the best fit to the equations deduced assuming random nucleation, followed by linear growth of nuclei, with possible ingestion and interference of reacting zones. The activation energy of nucleus growth is 32 to 33 kcal/g-molecule, and that for nucleation probably between 40 and 45 kcal/g-molecule.

scholarly journals Kinetics of the decomposition and the estimation of the stability of 10% aqueous and non-aqueous hydrogen peroxide solutions

2014 ◽  
Vol 27 (4) ◽  
pp. 213-216 ◽  
Author(s):  
Maria Zun ◽  
Dorota Dwornicka ◽  
Katarzyna Wojciechowska ◽  
Katarzyna Swiader ◽  
Regina Kasperek ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Decomposition Rate ◽  
Aqueous Hydrogen Peroxide ◽  
Decomposition Rate Constant ◽  
First Order ◽  
First Order Kinetics ◽  
C 30 ◽  
The Stability ◽  
Kinetics Of

Abstract In this study, the stability of 10% hydrogen peroxide aqueous and non-aqueous solutions with the addition of 6% (w/w) of urea was evaluated. The solutions were stored at 20°C, 30°C and 40°C, and the decomposition of hydrogen peroxide proceeded according to first-order kinetics. With the addition of the urea in the solutions, the decomposition rate constant increased and the activation energy decreased. The temperature of storage also affected the decomposition of substance, however, 10% hydrogen peroxide solutions prepared in PEG-300, and stabilized with the addition of 6% (w/w) of urea had the best constancy.

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