Reaction Kinetics and Mechanism of Sulfuric Acid-Catalyzed Acetolysis of Acylated Methyl L-Ribofuranosides

2009 ◽  
Vol 2009 (32) ◽  
pp. 5666-5676 ◽  
Author(s):  
Jonas J. Forsman ◽  
Johan Wärnå ◽  
Dmitry Yu. Murzin ◽  
Reko Leino
Keyword(s):  
Sulfuric Acid ◽  
Reaction Kinetics ◽  
Kinetics And Mechanism ◽  
Acid Catalyzed

Sulfuric acid-catalyzed acetolysis of anomeric ethyl 2,3,4,6-tetra-O-acetyl-d-glucopyranosides: kinetics and mechanism

1995 ◽  
Vol 279 ◽  
pp. 107-116 ◽  
Author(s):  
Józef Kaczmarek ◽  
Magda Preyss ◽  
Harri Lönnberg ◽  
Janusz Szafranek
Keyword(s):  
Sulfuric Acid ◽  
Kinetics And Mechanism ◽  
Acid Catalyzed

Reaction kinetics and mechanism of acid-catalyzed anomerization of 1-O-acetyl-2,3,5-tri-O-benzoyl-l-ribofuranose

2009 ◽  
Vol 344 (9) ◽  
pp. 1102-1109 ◽  
Author(s):  
Jonas J. Forsman ◽  
Johan Wärnå ◽  
Dmitry Yu. Murzin ◽  
Reko Leino
Keyword(s):  
Reaction Kinetics ◽  
Kinetics And Mechanism ◽  
Acid Catalyzed

THE WALLACH REARRANGEMENT: PART II. KINETICS AND MECHANISM OF THE ACID-CATALYZED REARRANGEMENT OF AZOXYBENZENE

1965 ◽  
Vol 43 (4) ◽  
pp. 862-875 ◽  
Author(s):  
E. Buncel ◽  
B. T. Lawton
Keyword(s):  
Sulfuric Acid ◽  
Proton Transfer ◽  
Acid Concentration ◽  
Entire Range ◽  
Kinetics And Mechanism ◽  
The Other ◽  
Rate Data ◽  
Spectrophotometric Methods ◽  
Aqueous Sulfuric Acid ◽  
Acid Catalyzed

The rate of rearrangement of azoxybenzene to p-hydroxyazobenzene has been measured in 75.3–96.4% sulfuric acid at 25° and in 65.0–90.4% sulfuric acid at 75.5° by spectrophotometric methods. The pKa of azoxybenzene in aqueous sulfuric acid has also been determined. It is found that although azoxybesssnzene is almost completely protonated over the entire range of acid concentration studied, the rate increases by more than 1 000-fold. A two-proton process is therefore indicated and mechanisms are proposed involving a dication (II) as the key intermediate. The rate data do not allow differentiation between two proposed mechanisms, one involving two equilibrium protonations, and the other a single equilibrium protonation followed by rate-determining proton transfer. Past mechanisms of the Wallach rearrangement are discussed.

Sulfuric acid-catalyzed acetolysis of anomeric methyl 2,3,4,6-tetra-O-acetyl-d-mannopyranosides: kinetics and mechanism

2000 ◽  
Vol 325 (1) ◽  
pp. 16-29 ◽  
Author(s):  
Józef Kaczmarek ◽  
Zbigniew Kaczyński ◽  
Zygmunt Trumpakaj ◽  
Janusz Szafranek ◽  
Magda Bogalecka ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Kinetics And Mechanism ◽  
Acid Catalyzed

Reaction Kinetics in Acid-Catalyzed Deprotection of Polymer Films

2012 ◽  
Vol 116 (46) ◽  
pp. 24706-24716 ◽  
Author(s):  
Ginusha M. Perera ◽  
Yogendra Narayan Pandey ◽  
Abhijit A. Patil ◽  
Gila E. Stein ◽  
Manolis Doxastakis
Keyword(s):  
Reaction Kinetics ◽  
Polymer Films ◽  
Acid Catalyzed

scholarly journals Hydrothermal Pretreatment of Wheat Straw: Effects of Temperature and Acidity on Byproduct Formation and Inhibition of Enzymatic Hydrolysis and Ethanolic Fermentation

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 487
Author(s):  
Dimitrios Ilanidis ◽  
Stefan Stagge ◽  
Leif J. Jönsson ◽  
Carlos Martín
Keyword(s):  
Mass Spectrometry ◽  
Sulfuric Acid ◽  
Wheat Straw ◽  
High Performance ◽  
Enzymatic Saccharification ◽  
Hydrothermal Pretreatment ◽  
Gas Chromatography Mass Spectrometry ◽  
Enzymatic Digestibility ◽  
Acid Catalyzed ◽  
Pretreatment Conditions

Biochemical conversion of wheat straw was investigated using hydrothermal pretreatment, enzymatic saccharification, and microbial fermentation. Pretreatment conditions that were compared included autocatalyzed hydrothermal pretreatment at 160, 175, 190, and 205 °C and sulfuric-acid-catalyzed hydrothermal pretreatment at 160 and 190 °C. The effects of using different pretreatment conditions were investigated with regard to (i) chemical composition and enzymatic digestibility of pretreated solids, (ii) carbohydrate composition of pretreatment liquids, (iii) inhibitory byproducts in pretreatment liquids, (iv) furfural in condensates, and (v) fermentability using yeast. The methods used included two-step analytical acid hydrolysis combined with high-performance anion-exchange chromatography (HPAEC), HPLC, ultra-high performance liquid chromatography-electrospray ionization-triple quadrupole-mass spectrometry (UHPLC-ESI-QqQ-MS), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Lignin recoveries in the range of 108–119% for autocatalyzed hydrothermal pretreatment at 205 °C and sulfuric-acid-catalyzed hydrothermal pretreatment were attributed to pseudolignin formation. Xylose concentration in the pretreatment liquid increased with temperature up to 190 °C and then decreased. Enzymatic digestibility was correlated with the removal of hemicelluloses, which was almost quantitative for the autocatalyzed hydrothermal pretreatment at 205 °C. Except for the pretreatment liquid from the autocatalyzed hydrothermal pretreatment at 205 °C, the inhibitory effects on Saccharomyces cerevisiae yeast were low. The highest combined yield of glucose and xylose was achieved for autocatalyzed hydrothermal pretreatment at 190 °C and the subsequent enzymatic saccharification that resulted in approximately 480 kg/ton (dry weight) raw wheat straw.

ChemInform Abstract: CYCLOHEXADIENYL CATIONS. 7. KINETICS AND MECHANISM OF THE ACID-CATALYZED DIENOL-BENZENE REARRANGEMENT

1978 ◽  
Vol 9 (23) ◽  
Author(s):  
V. P. VITULLO ◽  
M. J. CASHEN ◽  
J. N. MARX ◽  
L. J. CAUDLE ◽  
J. R. FRITZ
Keyword(s):  
Kinetics And Mechanism ◽  
Acid Catalyzed
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