3. Cellulose
๏ฑ It is the most abundant naturally occurring organic substance
๏ฑ Representing about1.5ร1012 tons annual biomass production
๏ฑ First described in 1838 by French chemist โAnselm Payenโ
๏ฑ It occurs in almost pure form in cotton fiber at around 98%.
๏ฑ As a raw material, cellulose has been used about150 years
๏ฑ First thermoplastic polymer material called โCelluloidโ
Manufactured by Hyatt Manufacturing Company in 1870
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๏ฑ Tollens in 1895 and Nastukoff in 1900 recognized that cellulose is a
linear polymer of glucose by x-ray pattern analysis.
๏ฑ In 1920 it is discovered that celluloses in delignified wood pulp,
flax, ramie, and cotton.
๏ฑ The Chinese discovered the usefulness of cellulose and developed a
process in A.D. 100 that gave them that most wonderful of
inventions... paper.
๏ฑ Create other products such as rayon and the transparent film called
cellophane.
๏ฑ In Vascular plants cellulose is synthesized at the plasma membrane
by rosette terminal complexes (RTCs) (Hexameric protein
structures, approximately 25 nm in diameter).
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Pyranose
Pyranose is any cyclic isomer that has a five carbons and one oxygen in a ring of
six atoms
Furanose
Any cyclic isomer that has a four carbons and one oxygen in a ring of five atoms
Cellobiose
Cellobiose consists of two glucose molecules linked by a ฮฒ(1โ4) bond
Some definitions
Pyranose Furanose
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6. Structure of cellulose
It is a Homopolymer of Glucose
It is a Carbohydrate composed of Carbon(49.39%), Oxygen
(44.4%) and Hydrogen (6.17%).
The molecular formula is (C6H10O5)n
Unbranched chained polymer of glucose
Cellulose Microfibrils in plants appear to be 4โ10 nm wide under the
electron microscope (Emons 1988, McCann et al 1990)
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Glucose
It is a simple Aldohexosic Monosaccharide.
It is a hexose ( 6 carbon) also aldose( --COH radical present in the terminal Carbon)
The molecular formula of Glucose is C6H12O6
A sugar with a pyranosic structure
An aldehyde is an organic compound containing a formyl functional (-CHO) group.
An Ketone is an organic compound containing a carbonyl functional (-CO-) group.
AldehydeKetone
R= Chain of Aliphatic or Aromatic hydrocarbon
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6
1
23
4 1
23
4
6
5 5
H2O
O
H2O
O
O O
1,4 D Glycopyranosic bond
Formation of Cellulose from Glucose
B,1-4, D-Anhydroglucopyranose units linked by (1,4)-glycosidic bonds
Cellulose synthase enzyme
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Crystalline and Amorphous region
Crystalline region: Intra and Inter molecular bonding is so strong
Do not absorb much moisture
Amorphous region: Bonding is week
Absorb too much moisture
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Cellulose formation in woody plants
Photosynthesis
Sap conduction
(C6H12O6)
Plasma membrane
Rosette terminal complexes (RTCs)
Spinsโ microfibril into cell wall
Cell division
6H20 + 6CO2
___________________ C6H12O6 + 6O2
Sunlight
Chlorophyll
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Physical Properties
๏ฑCellulose is non toxic, biodegradable solid homo-biopolymer.
๏ฑAt pure state white in color.
๏ฑMolecular mass is around 1.44 ร 106 to 1.8 ร 106 g
๏ฑDensity of 1.52โ1.54 g/cm3 (at 20ยฐC)
๏ฑHigh tensile and compressive strength
๏ฑCross bonding gives the maximum strength
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๏ฑ Cellulose is very much stable in thermal conduction
๏ฑ Cellulose shows thermal softening at 231-253ยฐC
๏ฑ Not a thermoplastic polymer
Thermal Properties
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Electrical Properties
๏ฑCellulose shows very low conductivity and high resistivity of
electricity
๏ฑPure cellulose shows maximum resistivity and water content
decreases resistivity
๏ฑRelative humidity also affect the electrical resistivity
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Chemical Properties
๏ฑ DP is 8000-10000
๏ฑ Isolable is water but uptake water around 8-14% at 60% relative
humidity and 20แตC
๏ฑ Soluble in organic chemicals
๏ฑ Give anhydrous reaction with concentrated acids
๏ฑ Reacts with Hydrocarbons, alcohols, ketones, acids, esters, amides,
halogenated hydrocarbons, hydrazine etc.
๏ฑ Reacts with strong base. Reacting order is,
For cations the order of reactivity
For anions the order is,
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Some swelling agents of cellulose
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Reaction with water
๏ฑ Cellulose soak water very slowly.
๏ฑ It uptake 8-14% moisture
๏ฑ Water is attached with strong hydrogen
bonding.
๏ฑ Relative humidity and temperature is
important.
๏ฑ Crystalline cellulose uptake less water than
amorphous
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Reaction with strong base
Reacts with strong base quickly.
According to the reactivity with base it can be separated into three types:
(i) ฮฑ cellulose, (ii) ฮฒ cellulose, (iiii)ฮณ cellulose
In 17.5% NaOH solution Insoluble: ฮฑ cellulose
Soluble but precipitated in neutral solution: ฮฒ cellulose
Very much soluble: ฮณ cellulose
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Cellulose Extraction from wood
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Cellulose Extraction from wood contโฆ
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Use of cellulose
Cotton: composed of 87 -90% cellulose with the cotton fibers containing polymer
chains
Pharmaceuticals: Medicines are derived from plants cellulose, cellulose acetate , etc.
Cellophane: Can be obtained when a viscous cellulose reacts with acid (sulfuric acid)
Bomb: Cellulose trinitrate is used as a propellant for bullets due the fact that nitrate โOH
group can be explosive.
Energy Drinks: Glucuronolacton, vitamins, and carbohydrates
Industrial Sugar, biofuel production, using oil production, ester production
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1. Beck-Candanedo, S., Roman, M., & Gray, D. G. (2005). Effect of reaction
conditions on the properties and behavior of wood cellulose nanocrystal
suspensions. Biomacromolecules, Vol.6, No.2, pp. 1048-1054.
2. Boruvkova, K, and Wiener, J 2011, Water Absorption in Carboxymethyl Cellulose,
AUTEX Research Journal, Vol. 11, No4, December 2011
3. Duran, N., Lemes, A. P., Duran, M., Freer, J., & Baeza, J. (2011). A Mini review of
Cellulose Nanocrystals and Its Potential Integration as Co-Product in Bioethanol
Production. Journal of the Chilean Chemical Society, Vol.56, No.2, pp. 672-677
4. Emons AMC. 1988. Methods for visualizing cell wall texture. Acta Bot. Neerl.
37:31โ38.
5. OSullivan, A. C. (1997). Cellulose: the structure slowly unravels. Cellulose, Vol.4,
No.3, pp. 173-207.
6. http://dx.doi.org/10.5772/46512
7. http://en.wikipedia.org
8. http://www.ethanolrfa.org
9. http://www.scienceclarified.com/Ca-Ch/Cellulose.html
References
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