Acid-catalyzed conversion of mono- and poly-sugars into platform chemicals: Effects of molecular structure of sugar substrate

2013 ◽  
Vol 133 ◽  
pp. 469-474 ◽  
Author(s):  
Xun Hu ◽  
Liping Wu ◽  
Yi Wang ◽  
Yao Song ◽  
Daniel Mourant ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Platform Chemicals ◽  
Acid Catalyzed

scholarly journals Efficient conversion of glucosamine to levulinic acid in a sulfamic acid-catalyzed hydrothermal reaction

RSC Advances ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 3198-3205 ◽  
Author(s):  
Hyo Seon Kim ◽  
Sung-Koo Kim ◽  
Gwi-Taek Jeong
Keyword(s):  
Levulinic Acid ◽  
Active Sites ◽  
Hydrothermal Reaction ◽  
Sulfamic Acid ◽  
Efficient Conversion ◽  
Platform Chemicals ◽  
Acid Catalyzed

Glucosamine, which is a monomer of chitosan, and sulfamic acid, which has dual active sites, were employed as substrate and catalyst, respectively, to produce the bio-based platform chemicals LA and 5-HMF.

scholarly journals Kinetics and Chemorheological Analysis of Cross-Linking Reactions in Humins

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1804 ◽  
Author(s):  
Sangregorio ◽  
Guigo ◽  
Jong ◽  
Sbirrazzuoli
Keyword(s):  
Complex Viscosity ◽  
Isoconversional Method ◽  
Effect Of Temperature ◽  
Diffusion Control ◽  
Model Free ◽  
Platform Chemicals ◽  
Model Free Kinetics ◽  
Acid Catalyzed ◽  
Advanced Isoconversional Method ◽  
Kinetics Of

Humins is a biomass-derived material, co-product of the acid-catalyzed conversion of cellulose and hemicellulose to platform chemicals. This work presents a thorough study concerning the crosslinking kinetics of humins by chemorheological analysis and model-free kinetics under isothermal and non-isothermal curing. Humins can auto-crosslink under the effect of temperature, and the reaction can be fastener when adding an acidic initiator. Thus, the effect of P-Toluenesulfonic acid monohydrate (pTSA) on the crosslinking kinetics was also studied. The dependencies of the effective activation energy (Eα-dependencies) were determined by an advanced isoconversional method and correlated with the variation of complex viscosity during curing. It is shown that humins curing involves multi-step complex reactions and that the use of an acidic initiator allows faster crosslinking at lower temperatures, involving lower Eα. The shift from chemical to diffusion control was also estimated.

PRESSURE EFFECT AND MECHANISM IN THE ACID-CATALYZED HYDRATION OF PROPYLENE AND ISOBUTYLENE

1964 ◽  
Vol 42 (5) ◽  
pp. 1019-1026 ◽  
Author(s):  
B. T. Baliga ◽  
E. Whalley
Keyword(s):  
Molecular Structure ◽  
Strong Evidence ◽  
Pressure Effect ◽  
Transition States ◽  
Effect Of Temperature ◽  
Kcal Mole ◽  
Effect Of Pressure ◽  
Entropy Of Activation ◽  
Acid Catalyzed ◽  
Arrhenius Energy

The effect of pressure up to 3 kbar on the rate of the acid-catalyzed hydration of propylene and isobutylene has been measured. The volumes of activation are: for propylene at 100 °C−9.6 ± ~1.0 cm3 mole−1, and for isobutylene at 35 °C− 11.5 ± ~1.0 cm3 mole−1. The effect of temperature in the range 90–120 °C on the rate of hydration of propylene at 100 bar was measured. At 100 °C the Arrhenius energy is 27.1 ± ~1.0 kcal mole−1 and the entropy of activation is −5.4 ± ~2.5 cal deg−1 mole−1. Both the volumes and entropies of activation strongly indicate that a molecule of water is present in the transition states, which can therefore be represented as [olefin. H+•H2O]≠. There appears to be no strong evidence regarding the molecular structure of the transition states.

Mediating acid-catalyzed conversion of levoglucosan into platform chemicals with various solvents

2012 ◽  
Vol 14 (11) ◽  
pp. 3087 ◽  
Author(s):  
Xun Hu ◽  
Liping Wu ◽  
Yi Wang ◽  
Daniel Mourant ◽  
Caroline Lievens ◽  
...  
Keyword(s):  
Platform Chemicals ◽  
Acid Catalyzed

Influence of conformational factors on acid-catalyzed cyclizations of germacranolides: Molecular structure of the cyclization products of gallicin and 8α-hydroxygallicin (shonachalin a)

1995 ◽  
Vol 1995 (10) ◽  
pp. 1837-1841 ◽  
Author(s):  
J. Alberto Marco ◽  
Juan F. Sanz-Cervera ◽  
Vicente García-Lliso ◽  
Luis R. Domingo ◽  
Miguel Carda ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Acid Catalyzed

Structural analysis of humins formed in the Brønsted acid catalyzed dehydration of fructose

2018 ◽  
Vol 20 (5) ◽  
pp. 997-1006 ◽  
Author(s):  
Ziwei Cheng ◽  
Jeffrey L. Everhart ◽  
George Tsilomelekis ◽  
Vladimiros Nikolakis ◽  
Basudeb Saha ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Structural Analysis ◽  
Mass Spectrometric ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Fructose Dehydration ◽  
Mass Spectrometric Techniques

Multistage dissolution experiments of humins, obtained from fructose dehydration, were performed in various solvents to investigate the solubility and molecular structure using spectroscopic, chromatography and mass spectrometric techniques.

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