Thermocatalytic depolymerization of kraft lignin to guaiacols using HZSM-5 in alkaline water–THF co-solvent: a realistic approach

2019 ◽  
Vol 21 (14) ◽  
pp. 3864-3881 ◽  
Author(s):  
Deepak Raikwar ◽  
Saptarshi Majumdar ◽  
Debaprasad Shee
Keyword(s):  
Batch Reactor ◽  
Kraft Lignin ◽  
High Conversion ◽  
Alkaline Water ◽  
Structural Modifications ◽  
Realistic Approach

A study representing depolymerization of kraft lignin in a batch reactor with higher loading attaining high conversion and guaiacol selectivity simultaneously and its correlation with structural modifications.

scholarly journals Correction: Catalytic hydrogenolysis of kraft lignin to monomers at high yield in alkaline water

2017 ◽  
Vol 19 (17) ◽  
pp. 4186-4186 ◽  
Author(s):  
Shi-Chao Qi ◽  
Jun-ichiro Hayashi ◽  
Shinji Kudo ◽  
Lu Zhang
Keyword(s):  
Kraft Lignin ◽  
High Yield ◽  
Alkaline Water ◽  
Catalytic Hydrogenolysis

Correction for ‘Catalytic hydrogenolysis of kraft lignin to monomers at high yield in alkaline water’ by Shi-Chao Qi et al., Green Chem., 2017, 19, 2636–2645.

scholarly journals Chemical Characterization of Kraft Lignin Prepared from Mixed Hardwoods

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4861
Author(s):  
Ji-Sun Mun ◽  
Justin-Alfred Pe Pe III ◽  
Sung-Phil Mun
Keyword(s):  
Carbon Content ◽  
Structural Changes ◽  
Chemical Characterization ◽  
Structural Features ◽  
Kraft Lignin ◽  
Kraft Pulping ◽  
Nucleophilic Attack ◽  
Low Oxygen ◽  
Structural Modifications

Chemical characterization of kraft lignin (KL) from mixed hardwoods (Acacia spp. from Vietnam and mixed hardwoods (mainly Quercus spp.) from Korea) was conducted for its future applications. To compare the structural changes that occurred in KL, two milled wood lignins (MWLs) were prepared from the same hardwood samples used in the production of KL. Elemental analysis showed that the MWL from acacia (MWL-aca) and mixed hardwood (MWL-mhw) had almost similar carbon content, methoxyl content, and C9 formula. KL had high carbon content but low oxygen and methoxyl contents compared to MWLs. The C9 formula of KL was determined to be C9H7.29O2.26N0.07S0.12(OCH3)1.24. The Mw of KL and MWLs was about 3000 Da and 12,000–13,000 Da, respectively. The structural features of KL and MWLs were investigated by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectrometry (1H, 13C NMR). The analyses indicated that KL underwent severe structural modifications, such as γ-carbon cleavage, demethylation, and polycondensation reactions during kraft pulping, which resulted in increased aromatic content and decreased aliphatic content. The main linkages in lignin, β-O-4 moieties, were hardly detected in the analysis as these linkages were extensively cleaved by nucleophilic attack of SH- and OH- during pulping.

Catalytic hydrogenolysis of kraft lignin to monomers at high yield in alkaline water

2017 ◽  
Vol 19 (11) ◽  
pp. 2636-2645 ◽  
Author(s):  
Shi-Chao Qi ◽  
Jun-ichiro Hayashi ◽  
Shinji Kudo ◽  
Lu Zhang
Keyword(s):  
Kraft Lignin ◽  
High Yield ◽  
Alkaline Water ◽  
Catalytic Hydrogenolysis

The yield of hydrogenolytic depolymerization to the monomers of kraft lignin dissolved in alkaline water is largely increased by the pretreatment of stretching lignin macromolecules.

scholarly journals Characterization of Fast Pyrolysis Bio-Oil from Hardwood and Softwood Lignin

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 887
Author(s):  
Zahra Echresh Zadeh ◽  
Ali Abdulkhani ◽  
Basudeb Saha
Keyword(s):  
Batch Reactor ◽  
Sustainable Energy ◽  
Kraft Lignin ◽  
Energy Sources ◽  
Chemical Extraction ◽  
Solvent Extraction Method ◽  
Bio Oil ◽  
Chemical Groups ◽  
Renewable And Sustainable Energy

The depletion of fossil fuel reserves and the increase of greenhouse gases (GHG) emission have led to moving towards alternative, renewable, and sustainable energy sources. Lignin is one of the significant, renewable and sustainable energy sources of biomass and pyrolysis is one of the most promising technologies that can convert lignocellulosic biomass to bio-oil. This study focuses on the production and characterization of bio-oil from hardwood and softwood lignin via pyrolysis process using a bench-scale batch reactor. In this study, a mixed solvent extraction method with different polarities was developed to fractionate different components of bio-crude oil into three fractions. The obtained fractions were characterized by using gas chromatography and mass spectrometry (GCMS). The calculated bio-oil yields from Sigma Kraft lignin and Chouka Kraft lignin were about 30.2% and 24.4%, respectively. The organic solvents, e.g., toluene, methanol, and water were evaluated for chemical extraction from bio-oil, and it was found that the efficiency of solvents is as follows: water > methanol > toluene. In both types of the bio-oil samples, phenolic compounds were found to be the most abundant chemical groups which include phenol, 2-methoxy, 2-methoxy-6-methylphenol and phenol, 4-ethyl-2-methoxy that is due to the structure and the originality of lignin, which is composed of phenyl propane units with one or two methoxy groups (O-CH3) on the aromatic ring.

Experimental investigation of vinyl chloride polymerization at high conversion: semi-batch reactor modelling

Polymer ◽  
1991 ◽  
Vol 32 (11) ◽  
pp. 2087-2095 ◽  
Author(s):  
T.Y Xie ◽  
A.E Hamielec ◽  
P.E Wood ◽  
D.R Woods
Keyword(s):  
Experimental Investigation ◽  
Vinyl Chloride ◽  
Batch Reactor ◽  
High Conversion

Structural modifications of intercellular junctions.

1978 ◽  
Vol 36 (2) ◽  
pp. 330-331
Author(s):  
J. Metz ◽  
M. Merlo ◽  
W. G. Forssmann
Keyword(s):  
Gap Junctions ◽  
Intercellular Junctions ◽  
Cell Isolation ◽  
Extrahepatic Cholestasis ◽  
Structural Modifications ◽  
Pancreatic Duct Ligation ◽  
Pancreatic Cells ◽  
Duct Ligation ◽  
Thin Sectioning ◽  
And Function

Structure and function of intercellular junctions were studied under the electronmicroscope using conventional thin sectioning and freeze-etch replicas. Alterations of tight and gap junctions were analyzed 1. of exocrine pancreatic cells under cell isolation conditions and pancreatic duct ligation and 2. of hepatocytes during extrahepatic cholestasis.During the different steps of cell isolation of exocrine pancreatic cells, gradual changes of tight and gap junctions were observed. Tight junctions, which formed belt-like structures around the apex of control acinar cells in situ, subsequently diminished, became interrupted and were concentrated into macular areas (Fig. 1). Aggregations of membrane associated particles, which looked similar to gap junctions, were intermixed within tight junctional areas (Fig. 1). These structures continously disappeared in the last stages of the isolation procedure. The intercellular junctions were finally separated without destroying the integrity of the cell membrane, which was confirmed with porcion yellow, lanthanum chloride and horse radish peroxidase.

Feasible Ways to Achieve High Conversion in Thorium-Fueled CANDU and PWR Reactors

2009 ◽  
pp. 62-72 ◽  
Author(s):  
P. Guillemin ◽  
A. Nuttin ◽  
A. Bidaud ◽  
J. Brizi ◽  
N. Capellan ◽  
...  
Keyword(s):  
High Conversion

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.

Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 24-30 ◽  
Author(s):  
NIKLAS BERGLIN ◽  
PER TOMANI ◽  
HASSAN SALMAN ◽  
SOLVIE HERSTAD SVÄRD ◽  
LARS-ERIK ÅMAND
Keyword(s):  
Circulating Fluidized Bed ◽  
Black Liquor ◽  
Chloride Content ◽  
Pilot Scale ◽  
High Energy ◽  
Kraft Lignin ◽  
High Energy Density ◽  
Alkali Chloride ◽  
Cfb Boiler ◽  
Solid Biofuel

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

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