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KING SCollege
Founded I8LONDON
University of London
,
Arni Saleh
Ph.D. student, xx cycle
12 December 2007
ActivityPresentation
e-mail: [email protected]
Presentation outline
• Background• Biomass Pretreatment• Process for extract lignin materials• Lignin extractions • Study of lignin extractions
BackgroundWhat is Bagasse?
• Bagasse material– Cellulose 33-48% – Hemicellulose 19-43% – Lignin 6-32%
• Renewable Resource, Economics and EnvironmentIncreasing importance is being given to biomass as a renewable and environment friendly resource, which has motivated a great number of economic utilization as starting materials for various bioproduction.
Background What is lignin?
• Natural lignin composition and structure are unknown.
• It is a heterogeneous polymer.
• It is made up of three principal monomers.
Biomass Pretreatment
Bagasse was first dried in sunlight, then in oven at 105°C, cut into small pieces and stored in desiccator at room temperature. The dried biomass of bagasse was ground using a laboratory mill and screened to prepare 40 mesh powder.
Extraction of lignin from sugarcane bagasse
Dried sugarcane bagasseDried sugarcane bagasse
Grounding and screening to prepare 40 mesh powder
Grounding and screening to prepare 40 mesh powder
Treatment with NaOH in autoclave at 121°C, for 1 h
Treatment with NaOH in autoclave at 121°C, for 1 h
Solid residueSolid residue
WasteWaste
Extract Extract
a) Filtration with 0.45 m pore filtersb) Acid treatment with H3PO4 (pH 3)
c) Filtration with 0.20 m pore filters
a) Filtration with 0.45 m pore filtersb) Acid treatment with H3PO4 (pH 3)
c) Filtration with 0.20 m pore filters
HPLC Analysis HPLC Analysis
Hydrolysis method
Alkaline sugarcane bagasse hydrolysis
Lignin extraction
Bgasse (g) alkaline (NaOH)
treatment (M)
% of main components extracted
p-coumaric acid
Ferulic acid
Syringic acid Vanillin
0.5 79.61 16.21 1.10 3.081.0 76.36 17.58 1.49 4.57
1.0 2.0 74.01 19.03 1.81 5.143.0 75.78 18.49 1.69 4.054.0 76.10 18.78 1.79 3.340.5 76.83 15.44 3.19 4.531.0 67.40 18.90 3.97 9.72
2.0 2.0 69.04 19.26 3.37 8.333.0 67.27 21.12 3.95 7.654.0 78.91 15.80 2.45 2.850.5 83.41 14.96 0.82 0.801.0 82.13 16.04 0.97 0.86
3.0 2.0 79.98 17.31 1.34 1.373.0 80.59 17.33 1.50 0.594.0 78.79 18.36 1.82 1.040.5 76.04 19.10 1.79 3.071.0 73.79 20.59 2.38 3.24
5.0 2.0 67.00 24.40 3.31 5.283.0 71.68 21.10 2.87 4.354.0 71.49 20.23 3.18 5.10
Study of lignin extractions
• Experimental Techniques• The determination of pKa by Uv/Vis
Spectroscopy• Study of aggregation by Uv/Vis Spectroscopy
Results• A) p-Coumaric acid result data• B) Ferulic acid result data• C) Syringic acid result data• D) Vanillin result data
The determination of pKa by Uv/Vis Spectroscopy
17
p-Coumaric acid result data
Absorbance spectra of p-Coumaric acid, in only solvent distilled water, an environment not resistant to the effect of pH change from 2to 7.
Changes of a solution pH cause changes in the electrostatic interactions within the component and the solvent system.
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.00.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
A31
0
pH
The effect of pH between 2 and 5, in this range pCA is reversible and the maximum value of absorbance is about pH 3.5; at max(310). The reversible points indicated the p-Coumaric acid is pure.
p-Coumaric acid result data
Ferulic acid result data
O
HOCH3
OH
OO
HOCH3 O
O O
OCH3
O
OpKa1 pKa2
pH=2 pH=7 pH=12
Ferulic acid
From the analysis of the plots Absorbance of pH Titration Curves Ferulic acid at max(322) and at max(346), the pKa1 and pKa2 values were obtained 4.72, 9.21 respectively.
Syringic acid result data
From the analysis of pH titration curves at max(270), and max(300)
were obtained the pKa1 = 4.47
pKa2 = 9.34O
HOCH3
OH
O
pKa1 pKa2
pH=2 pH=7 pH=12
Syringic acid
OCH3
O
HOCH3
O
O
OCH3
O
OCH3
O
O
OCH3
200 250 300 350 400
0
5000
10000
15000
20000
25000
Extinctio
n c
oeff
icie
nt,
(
M.c
m)-1
Wavelength, (nm)
pH1.97 pH2.44 pH2.90 pH3.56 pH4.08 pH4.50 pH4.95 pH6.40 pH6.90 pH7.29 pH7.72 pH7.95 pH8.75 pH9.50 pH10.90 pH11.50 pH12.14
pKa
pH=2 pH=12
Vanillin
O
O
OCH3OH
O
OCH3
Vanillin result data
pH Titration Curves of Vanillin, at max(348),
pKa = 7.25.
Study of aggregation by Uv/Vis Spectroscopy
• p-Coumaric acid • Other components are under investigations.
Absorbance spectra of a series of concentrations of p-Coumaric acid in ethanol
O
O
H
HO
O
O
H
OH
OH
O
HO
OH
O
HO+
0 2 4 6 8 100.0
0.2
0.4
0.6
0.8
Ab
sorb
an
ce
Concentration (M)
Maximum absorbance at 310 nm Y=0.08492X, R=0.99877, SD=0.01642
Conclusions
I am tested four aromatic compounds, p-Coumaric acid, Ferulic acid, Syringic acid and Vanillin. All they basically have phenyl
group and the first three also have the carboxylic acid chromophore. The first three have tow pKa values because they
have carbonyl group (>C=O) chromophore. The pKa value of a
chemical compound determines its solubility and stability.
In ethanol the p-Coumaric acid at high concentration makes dimerisation.
The four aromatic compounds
Compound FormulaMol. Wt (g/mol)
Structure pKa
p-Coumaric acid C9H8O3 164.15 4.5, 9.35
Ferulic acid C10H10O4 194.184.7, 9.2
Syringic acid C9H10O5 198.174.5, 9.34
Vanillin C8H8O3 152.14 7.3
OH
O
HO
OH3C
HO
O
OH3C
H3C
O
OH
HO
OH
O
OH
O
OCH3