KING SCollege

Founded I8LONDON

University of London

,

Arni Saleh

Ph.D. student, xx cycle

12 December 2007

ActivityPresentation

e-mail: arni@unige.it

arnisaleh@hotmail.com

KING SCollege

Founded I8LONDON

University of London

,

Aromatic compounds from Sugarcane Bagasse

Presentation outline

• Background• Biomass Pretreatment• Process for extract lignin materials• Lignin extractions • Study of lignin extractions

Background

• Bagasse material • Renewable resource, economics and

environment • What is lignin?

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

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.

Processes for extract lignin materials

• Hydrolysis method • Alkaline sugarcane bagasse hydrolysis

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

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

Experimental Techniques

Uv/Vis Spectroscopy

Beer-Lambert Law is A= cl = log10(Io/It)

Incident light Io

transmitted light

It

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

KING SCollege

Founded I8LONDON

University of London

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That’s all!Thank you very much for

your attention