scholarly journals Recent Development in Chemical Depolymerization of Lignin: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hai Wang ◽  
Melvin Tucker ◽  
Yun Ji
Keyword(s):  
High Pressure ◽  
Ionic Liquids ◽  
Supercritical Fluids ◽  
High Selectivity ◽  
Severe Reaction ◽  
Great Contribution ◽  
Reaction Conditions ◽  
Commercial Scale ◽  
High Pressure High Temperature ◽  
Acid Catalyzed

This article reviewed recent development of chemical depolymerization of lignins. There were five types of treatment discussed, including base-catalyzed, acid-catalyzed, metallic catalyzed, ionic liquids-assisted, and supercritical fluids-assisted lignin depolymerizations. The methods employed in this research were described, and the important results were marked. Generally, base-catalyzed and acid-catalyzed methods were straightforward, but the selectivity was low. The severe reaction conditions (high pressure, high temperature, and extreme pH) resulted in requirement of specially designed reactors, which led to high costs of facility and handling. Ionic liquids, and supercritical fluids-assisted lignin depolymerizations had high selectivity, but the high costs of ionic liquids recycling and supercritical fluid facility limited their applications on commercial scale biomass treatment. Metallic catalyzed depolymerization had great advantages because of its high selectivity to certain monomeric compounds and much milder reaction condition than base-catalyzed or acid-catalyzed depolymerizations. It would be a great contribution to lignin conversion if appropriate catalysts were synthesized.

Notizen: High Pressure Reactions, I Evidence for Two Concurrent Mechanisms in Lewis-Acid Catalyzed Alkylation of Aromatics with Olefins

1976 ◽  
Vol 31 (2) ◽  
pp. 277-278 ◽  
Author(s):  
H. Tiltscher ◽  
R. Lohmüller
Keyword(s):  
High Pressure ◽  
Pressure Range ◽  
Reaction Rate ◽  
Initial Reaction Rate ◽  
Product Formation ◽  
Initial Reaction ◽  
Homogeneous Reaction ◽  
Reaction Conditions ◽  
Alkylation Of Benzene ◽  
Acid Catalyzed

A kinetic study was made of the primary step of the alkylation of benzene with propylene and ferric chloride as catalyst under homogeneous reaction conditions at several pressures up to 2 kbar. Initial reaction rate of cumene formation shows a minimum in the medium pressure range, thus indicating that product formation occurs via two different reaction paths with opposite pressure dependence.

The Continuous Acid-Catalyzed Dehydration of Alcohols in Supercritical Fluids:  A New Approach to the Cleaner Synthesis of Acetals, Ketals, and Ethers with High Selectivity

1999 ◽  
Vol 121 (46) ◽  
pp. 10711-10718 ◽  
Author(s):  
William K. Gray ◽  
Fiona R. Smail ◽  
Martin G. Hitzler ◽  
Stephen K. Ross ◽  
Martyn Poliakoff
Keyword(s):  
Supercritical Fluids ◽  
High Selectivity ◽  
New Approach ◽  
Acid Catalyzed

Synthesis of Phenylsubstituted 2H,5H-Pyrano[ 4,3-b] pyran-5-ones and Related Heterocycles via a Domino Knoevenagel Condensation/ 6π-Electron Electrocyclization of 4-Hydroxy-6-phenyl-2H-pyran-2-one with Cyclic and Acyclic α, β-Unsaturated Aldehydes under Different Conditions Synthesis and Crystal Structure of the High-pressure Iron Borate β-FeB2O4 Synthesis and Crystal Structure of the High-pressure Iron Borate β-FeB2O4 Synthesis and Crystal Structure of the High-pressure Iron Borate β-FeB2O4 Synthesis and Crystal Structure of the High-pressure Iron Borate β-FeB2O4 Synthesis and Crystal Structure of the High-pressure Iron Borate β-FeB2O4

2009 ◽  
Vol 64 (8) ◽  
pp. 1-10 ◽  
Author(s):  
Heiko Leutbecher ◽  
Sylvia Rieg ◽  
Jürgen Conrad ◽  
Sabine Mika ◽  
Iris Klaiber ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Ionic Liquids ◽  
Knoevenagel Condensation ◽  
Single Step ◽  
Iron Borate ◽  
Reaction Conditions ◽  
Synthesis And Crystal Structure ◽  
Unsaturated Aldehydes

A range of new 7-phenyl-2H,5H-pyrano[4,3-b]pyran-5-ones and related tricyclic heterocycles was prepared in a single step by means of a domino Knoevenagel condensation/6π-electron electrocyclization under different reaction conditions, including thermal and microwave conditions. The influence of several ionic liquids as solvents was also studied

A high-pressure high-temperature setup for in situ Raman spectroscopy of supercritical fluids

2015 ◽  
Vol 205 ◽  
pp. 54-60 ◽  
Author(s):  
Marion Louvel ◽  
Amélie Bordage ◽  
Cécile Da Silva-Cadoux ◽  
Denis Testemale ◽  
Eric Lahera ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
High Temperature ◽  
Supercritical Fluids ◽  
In Situ Raman Spectroscopy ◽  
In Situ Raman ◽  
High Pressure High Temperature

High-Pressure High-Temperature Raman Spectroscopy of Liquid and Supercritical Fluids

2003 ◽  
Vol 57 (10) ◽  
pp. 1300-1303 ◽  
Author(s):  
Yuri E. Gorbaty ◽  
Galina V. Bondarenko ◽  
Eleni Venardou ◽  
Eduardo Garcia-Verdugo ◽  
Maia Sokolova ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
High Temperature ◽  
Supercritical Fluids ◽  
High Pressure High Temperature

scholarly journals Trace mild acid-catalysed Z→E isomerization of norbornene-fused stilbene derivatives: intelligent chiral molecular photoswitches with controllable self-recovery

2021 ◽  
Author(s):  
Taotao Hao ◽  
Yongsheng Yang ◽  
Wenting Liang ◽  
Chunying Fan ◽  
Xin Wang ◽  
...  
Keyword(s):  
Mineral Acid ◽  
Severe Reaction ◽  
Reaction Conditions ◽  
Strong Mineral Acid ◽  
Stilbene Derivatives ◽  
Acid Catalyzed ◽  
High Concentrations ◽  
Mild Acid

Stilbene derivatives are long known to undergo “acid-catalyzed” Z→E isomerization, where a strong mineral acid in high concentrations is practically demanded. Such severe reaction conditions often cause undesired by-reactions and...

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