This document provides safety precautions for laboratories and distilleries. For laboratories, it lists precautions like requiring lab coats and safety glasses with chemicals, prohibiting running or open-toed shoes, and procedures for chemical spills and accidents. For distilleries, it outlines safety measures like ensuring equipment is properly cooled and secured, keeping ignition sources away from flammable liquids, using fire extinguishers, and operating stills with ventilation. The document also explains fermentation processes, describing how enzymes convert sugars to ethanol and carbon dioxide through the action of yeast in a multi-step catalytic reaction. Key details on ethanol production, properties, consumption, and industrial fermentation methods are also summarized.

1. ANNEXURE-I
1. Safety Precaution used in Laboratory Level:i.
No running and jumping in laboratory areas shall be permitted.
ii.
Lab coats and safety glasses are required in laboratories employing
chemicals or bio hazards.
iii.
Foot wear and clothing are to be wear which will not create sparks.
iv.
Using nylon clothes is avoided as it can produce static electricity.
v.
Wash your hands frequently throughout the day and before leaving the
lab.
vi.
Do not smoke and carry the matches.
vii.
Keep all aisles and walk ways into the lab clear to provide a safe walking
surface.
viii.
Never pipette out by mouth. Always use a pipette bulb.
ix.
Wear apron while doing the experiment and also shoes.
x.
Be alert and don’t be in dream while handling chemicals and electrical
equipment’s.
xi.
Do not stopper on to glass tubing’s.
xii.
Report all incidents/accidents to your teacher immediately.
xiii.
Never throw sodium metal in sink.
xiv.
Notify your instructor about fire accidents immediately to take steps for
firefighting.
xv.
Chemical Burn:
General chemicals: Immediately warm off plenty of water.
xvi.
Acids: Wash with water and then with dilute Na2Co3 solutions.
xvii.
Bases: Wash with water.
1

2. 2. Safety Precautions used in Distillery Plant:i.
Don't distill in a closed room. Try and keep some through-draught (e.g.
both a window and door open)
ii.
If your still leaks (liquid or steam) - fix it instead of using it
iii.
Collect the alcohol securely – don’t put yourself in a position where it’s
easy to knock over the collection vessel etc., or bump the tube out of it.
This means having enough space to work in, well lit, tidy.
iv.
Keep a fire extinguisher with you (and on your side of whatever is going to
catch fire)
v.
If using electrical heating, have an RCD on the line (residual current
device - a fancy circuit breaker)
vi.
Check you’re still with water-only the first time you use it, to make sure
your condenser is up to the job. You don’t want vapor coming out of the
collection tube.
vii.
Be sober - it’s not a time to be making drunken mistakes.
viii.
Pay attention to the still - check it regularly (cooling water still flowing, no
leaks, collecting nicely, all temperatures OK).
ix.
Do the math - don't boil the still dry.
x.
Make sure the outlet tube is free flowing - not crimped or blocked in any
way.
xi.
Make sure the still design is such that you can't pressurize the still - it
should always be able to vent somehow to atmosphere. There shouldn't be
valves such that you can fully close the column off.
xii.
Don't smoke - you don't want ignition sources around a liquid as
flammable as gasoline.
2

3. ANNEXURE-II
3. Introduction to Fermentation:Fermentation process utilizes micro-biology in production chemical compounds.
These process yield simple structural chemicals, e.g. - ethanol, butanol or acetone
etc. Fermentation processes are also used for production of complex organics
chemicals such as medicinal, antibiotics and for chemicals of more complex
structure, such as citric and lactic acids derived from low-cost carbohydrate
sources.
The action of a specific micro-organism on a substrate to produce the
desired chemical compound is termed Fermentation. The majority of processes
required oxygen and are called classified as “Aerobic”. The few processes carried
out in the absence of air are classified as “anaerobic”.
Fermentation under controlled conditions involves chemical conversions
some of the more important processes are:
Oxidation: e.g. Alcohol to acetic acid, Sucrose to citric acid, and dextrose to
gluconic acid,
Reduction: e.g. Aldehydes to Alcohols, (acetyl dehyde to Ethyl Alcohols), and
Sulphur to Hydrogen Sulfide.
Hydrolysis: e.g. Starch to Glucose and Sucrose to Glucose and Fructose and on to
alcohol,
Esterification: e.g. Hexose phosphate from Hexose and Phosphoric acid.
Actually certain chemicals conversions can be carried out more efficiently by
fermentation then by chemical synthesis.
3

4. 4. Characteristics of Fermentation Process:
The five basic prerequisites of a good fermentation process are:i.
A micro-organism that forms desired end product. This organism must be
readily propagated and be capable of maintaining biological uniformity,
thereby giving predictable yields.
ii.
Economical raw materials for the substrate e.g. starch or on of several
sugars.
iii.
Acceptable yields.
iv.
Rapid Fermentation.
v.
A product that is rapidly recovered and purified.
4

5. 5. Introduction to Alcohols:Ethyl alcohol is one of the most important raw materials which is quite
frequently used. It is most important member of the alcohol series and is simply
known as “Alcohol”. It is also known as “Grain Alcohol” because it can be
prepared from starchy grains. It has become important by virtue of its
economically useful properties as a solvent and for synthesis of other
chemicals. Alcohol is sold as a tax paid alcohol or much more widely as nontaxed denatured alcohol.
In industries nomenclature alcohol means ethyl alcohol or ethanol
(C2H5OH).
Structure of Ethanol
Ethanol is an alternative energy source. When burned, ethanol produces a pale
blue flame with no residue and considerable energy, making it an ideal fuel. It
can be used as a fuel when blended with gasoline or in its original state. There
are three primary ways that ethanol can be used as a transportation fuel:
i.
ii.
iii.
As a blend of 10 percent ethanol with 90 percent unleaded gasoline called
“E-10 Unleaded”;
As a component of reformulated gasoline, both directly and/or as ethyl
tertiary butyl ether (ETBE); or
As a primary fuel with 85 parts of ethanol blended with 15 parts of
unleaded gasoline called “E-85.”
5

6. 6. Methods of Preparation of Ethyl Alcohol:On industrial scale, alcohols are prepared by the following methods:
A. Hydration of alkenes:
Alkenes are converted into alcohols by two methods:
i.
By direct addition of water at low temperature and high pressure in the
presence of mineral acids as catalyst.
ii.
By indirect method in which alkenes are passed through concentrated
H2SO4 to form alkyl hydrogen sulphates. These alkyl hydrogens
sulphates are hydrolysed by passing steam which gives alcohols.
B. Oxo Process:
Alkenes react with carbon monoxide and hydrogen in the presence of
cobalt carbonyl [Co(CO)4]2 as catalyst at high temperature and pressure
to give aldehydes. The catalytic hydrogenation of aldehydes gives
primary alcohols.
H2C=CH2+CO+H2
[Co (Co)4]2
High temp. &
Pressure
H2/Ni
CH3CH2CHO
Propanal
CH3CH2CH2OH
Propan-1-ol
C. Fermentation of Carbohydrates.
Ethanol is manufactured by fermentation of starch or sugar. Fermentation is
a process in which complex organic compounds are broken down into
simpler molecules by the action of biological catalysts known as enzymes.
Enzymes are complex organic compounds which acts as catalysts in reaction
taking place in living organisms. These are also called Bio-catalysts
6

7. ANNEXURE-III
7. Fermentation of Carbohydrates:7.1 Properties of Enzymes:
The important characteristics of enzymes are:
i.
High efficiency: Enzymes increase the speed of reaction up to 10
million times as compared to the uncatalysed reactions.
ii.
Extremely small quantities: Extremely small quantities of enzymes –as
small as millionth of a mole-can increase the rate of reaction by factors
of 103 to 106
iii.
Specificity: The enzymes are highly specific in nature. Almost every
biochemical reaction is controlled by its own specific enzymes. For
example, Maltase catalyses the hydrolysis of maltase. No other enzyme
can catalyse its hydrolysis.
iv.
Optimum temperature and pH: The enzymes are active at moderate
temperature (about 37oC) and pH (around 7).
v.
Control of activity of enzymes: The actions of enzymes are controlled
by various mechanisms and are inhibited by various organic and
inorganic molecules.
vi.
The activity of most enzymes is closely regulated.
7

8. 7.2 Enzymes catalyzed Reactions:
Bio chemists are trying to explain the exact molecular basis of enzyme
catalysis. The various steps involved in the enzyme catalyzed reaction are
given below:
i.
Binding of the enzymes (E) to substrate (S) to form a complex.
E+S
ES
ES is called the enzyme- substrate complex.
ii.
Product formation in the Complex.
ES
EP
Where EP is a complex of enzyme and product.
iii.
Release of product from the enzyme – Product complex.
EP
E+P
8

9. The catalystic property of enzymes is present at certain specific regions on their
surfaces. These are called active sites or catalystic sites. The active sites have
characteristic shape and fit suitably shaped specific substrate molecules. Specific
binding accounts for the high specificity of these enzyme reactions. The specificity
of fitting together of the substrate structure and the enzyme structure may be
compared as a Key fitting into a lock. The shape of the active site is of given
enzymes is such that only a specific substrate can fit into it, on the same way as
key can open a particular lock.
Enzyme Substrate Binding
(Lock and key mechanism)
9

10. 7.3 Introduction to Yeast:The word "yeast" comes from Old English gist, gyst, and from the IndoEuropean root yes-, meaning "boil", "foam", or "bubble". Yeasts are eukaryotic
microorganisms classified in the kingdom Fungi, with 1,500 species currently
described (estimated to be 1% of all fungal species). Yeasts are unicellular,
although some species with yeast forms may become multicellular. Yeast size
can vary greatly depending on the species, typically measuring 3–4 µm in
diameter.
Structure of Yeast
Raising bubbles from Yeast
10

11. Action of Yeast at the time of Fermentation
The yeast species Saccharomyces cerevisiae converts carbohydrates to carbon
dioxide and alcohols. This is because:
a. They grow vigorously.
b. They have high tolerance for alcohols.
c. They have a high capacity for producing a large yield of alcohol.
d. For yeast nutrients are needed such as small amount of phosphate and
nitrogenous compounds as well as favorable pH and temperature.
Properties of Baker Yeast:
Baker’s Yeast
Dry Materials
Nitrogen
Protein
Carbohydrates
Lipids
Property
30 - 33%
6.5 9.3%
40.6 - 58%
35 - 45%
5.0 - 7.5%
11

12. 7.4 Pertinent properties of Ethyl Alcohol (Ethanol):Molecular weight
Density
Melting Point
Boiling Point
Flash Point
Ignition Temperature
Explosive limits
Toxicity Limit
Grades
7.5
46.07
0.791 @ 20oC
-112oC
78.3oC
21oC
372oC
Lower = 3.5% by Volume
Upper = 19%
1000 ppm
Anhydrous, 95%, denatured.
Consumption Pattern:-
Ethyl alcohol serves largely as an intermediate for a number of other
chemical products. Its original prime use in blended power fuels has
virtually disappeared with increased petrol refinery capacity.
End Use Pattern
Synthetic rubber
Solvent
Polyethylene
Potable Spirits
Plastics
Acetaldehyde-acetic acid
Butyl acetate
Other Chemicals
Miscellaneous
India
33%
15%
13%
10%
9%
7%
5%
--8%
USA
--27%
------53%
--15%
5
12

13. 7.6
Ethyl Alcohol from Sugar solution (Molasses):Molasses is a non-crystalline of sugar obtained as mother liquor after
crystallization of sugar from sugar solution. This contains about 50% sugar. It
is diluted to about 10% solution. The process can be explained in the following
two stages:
a) Cultivation of Yeast in the molasses.
b) Recovery of Ethyl alcohol from cultivated solution.
I stage:
As shown in the diagram diluted solution is heated up to above room
temperature (40-50oC) and then yeast is added proportionality and kept for
cultivation for about 2-3 days. Yeast supplies the enzymes invertase and
zymase. The enzyme invertase hydrolysis sucrose to glucose and fructose. The
enzyme zymase converts glucose to ethanol and carbon dioxide.
Invertase
C12H22O11
+ H2O
C6H12O6 + C6H12O6
Sucrose
Glucose
Fructose
Zymase
C6H12O6
Glucose
2C2H5OH + 2CO2
H= -31.2K Cal
Ethanol
The formation of final products i.e., ethanol and carbon dioxide can be
observed by the bubbler (expanded bubbler) which is tied to the cultivation can
be observed in the diagram.
The fermented liquid which contains about 8-10% ethanol is called “Wash”.
13

14. 14

15. II Stage:
As observed in the diagram the “mash” is collected and fractionally distilled to
recover rectified spirit containing 95.6% alcohol. The final rectified alcohol is
stored in cans. Further dehydration with quick lime and distilling with sodium
or calcium gives 99.8% ethanol called absolute alcohol.
Laboratory Fermenter
15

16. ANNEXURE-IV
8. Industrial alcohol production by fermentation:
8.1 Flow Sheet:
8.2 Chemical Reaction:
a. Main Reaction:
Invertase
C12H22O11 +H2O
2C6H12O6
16

17. Zymase
C6H12O6
2C2H5OH + 2CO2; ∆H= -31.2 Kcal
b. Side Reaction:
2C6H12O6 + H2O
ROH + R’CHO
Higher mol. Wt. alcohols
8.3 Quantitative requirements:
a) Basis: 1 Ton of 100 % alcohol (1.26 kilometers) and 90% yield from total
sugar.
Molasses (50-55% total sugar)
Sulfuric acid (60o Be)
Ammonium sulfate
Coal
Process water
Cooling Water
Electricity
By-products: Co2
Fusel oil (higher mol. Wt. alcohols)
5.6 tons.
27 kg
2.5 kg
0.87 - 1.5 tons
12 tons
50 tons
35 KWH
0.76 tons
Residual cattle feed or fertilizer 0.20 – 0.60 ton
b) Plant capacity: 10-100 tons/day of ethyl alcohol.
17

18. 8.4 Process Description:
Molasses is diluted to a 10-15% sugar concentration and adjusted to a pH of 4-5
to support yeast growth which furnishes invertase zymase catalytic enzymes.
Nutrients such as ammonium and magnesium sulfate or phosphate are added
when lacking in molasses. This diluted mixture, called mash, is run into large
wooden or steel fermentation tanks
Yeast solution, grown by inoculating sterile mash, is added and fermentation
ensues with evolution of heat which is removed via cooling coils. The
temperature is kept at 20-30oC over a30-70 hour period, rising near the end to
35oC carbon dioxide may be utilized as a by-product by water scrubbing and
compressing; otherwise it is vented after scrubbing.
Separation of the 8-10% of alcohol in the fermented liquor called beer is
accomplished by a series of distillations. In the beer still, alcohol (5060%conc.) and undesirable volatiles such as aldehydes are taken off the top and
fed to the aldehyde still. Alcohol is pulled off as a side-stream spilt to the
rectifying column. In this final column, the azeotropic alcohol-water mixture of
95% ethanol is taken off as a top side-stream, condensed and run to storage
where it is spilt into three parts:
(1) Direct sale as potable, government controlled alcohol.
(2) Denatured by small additions of mildly toxic ingredients and sold for
industrial uses.
(3) Made anhydrous by ternary azeotropic distillation using benzene or
extractive distillation using ethylene glycol.
When fusel oil recovery is practiced, side-streams are drawn off near the bottom
of the aldehyde and rectifying columns and are separated by decantation. These
higher molecular weight alcohols are sold directly for solvents or are
fractionated to give predominately amyl alcohol.
The bottoms from the beer still, known as slops, are either discharged as waste
or concentrated by evaporation to cattle feed depending on fuel and by-product
sales economics.
18

19. 9. Influence of Reaction of Parameters:The following parameters influence the production of ethyl alcohol from
molasses by Fermentation.
The yield of ethyl alcohol depends on effective cultivation of yeast in the
molasses.
9.1
Optimization of pH:
As shown in the figure.1 the ethanol concentration gradually increase in pH
and reaches a maximum percentage of ethanol production when pH is equal to
4 and later it starts declining due to the lesser activity of yeast.
Optimum pH is 4.2 to 4.5
19

20. 9.2
Effect of fermentation temperature:
The sample maintained at an optimum pH (4pH), the ethanol production
increases with the increase in the temperature and reaches maximum value
at 35oC as shown in below figure.
Further the increasing temperature reduces the percentage of ethanol
production and is mainly due to the denature of the yeast cells.
20

21. 9.3
Effect of Molasses Concentration:
As shown in fig. 3 that the production of ethanol increases in sugar
molasses concentration and reaches maximum. Ethanol production of
sugar concentration of 300 gm/lt and further increasing sugar molasses
concentration inhibit the ethanol productivity.
21

22. 9.4
Effect of Yeast concentration:
When pH and temperature are maintained at 4 & 35oC from figure 4. It is
observed that as the concentration of yeast increases, the yield of ethanol
increases up to 2 gm. and then it starts to decrease.
22

23. ANNEXURE-V
10. Properties of Ethyl Alcohol:
10.1 Physical Properties:
The important physical properties of alcohols are:
i.
Physical state:
The lower members are colorless liquids having a characteristic smell and
burning taste. The higher members (having more than 12 carbon atoms) are
colorless, odorless, wax-like solids.
ii.
Associated nature:
Alcohols exit as associated molecules having intermolecular hydrogen
bonds as shown below,
R
Hydrogen Bonds
…….O
H…….O
R
H……O
H…..
R
This is due to the fact that there is large difference in electronegativity of
oxygen and hydrogen atoms. As a result the
O
H bonds is strongly polar and forms hydrogen bonds.
iii.
Boiling Point:
The lower member have low boiling point but with the increase in
molecular weight, the boiling point keep on increasing gradually. For
isomeric alcohols having the same number of carbon atoms, the boiling
points are in the order:
Primary
Compound
Boiling Point
≥ Secondary
n-Butyl Alcohol
391 K
≥
Tertiary
Iso-Butyl alcohol
373 K
Tert-buthyl alcohol
356 K
This is due to the fact that with branching, the surface area decreases and
therefore , the boiling point decreases.
23

24. It may be noted that alcohols have generally higher boiling points as
compared to other organic compound of similar molecular masses such as
hydrocarbons, ethers and haloalkanes. For example, the boiling point of ethyl
alcohol (mol. Mass=46) dimethyl ether (mol. Mass=46) and propane (mol.
mass=44) are:
Ethyl alcohol
351 K
iv.
Dimethyl ether
309 K
Propane
231K
This is due to the presence of hydrogen bonds in alcohols and their absence in
ethers and hydrocarbons. Because of hydrogen bonds in alcohols, these exists
as associated molecules rather than discrete molecules. Consequently, a large
amount of energy is required to break these bonds and therefore, their boiling
points are high.
Solubility:
The lower members of alcohol are highly soluble in water but the solubility
decreases with increases in molecular weight. The solubility of lower alcohols
in water is due to the formation of hydrogen bonds between alcohols and water
molecules.
R
R
Hydrogen Bonds
…….O
H…….O
H
v.
vi.
H……O
H…..O
H……
H
However, as the size of alcohol molecules increases, the alkyl group becomes
larger and prevents the formation of hydrogen bonds with water molecules and
hence the solubility goes a decreasing with increases in length of carbon chain
(or molecular mass of alcohol).
Amongst isomeric alcohols, the solubility increases with branching.
Density:
Generally, alcohols are lighter than water although the density increases with
the increase in molecular mass.
In toxicating effects:
Alcohols have in toxicating effects. Methanol is poisonous and is not good for
drinking purposes. It may cause blindness and even death. Ethanol has been
used for drinking purposes.
24

25. 10.2 Chemical Properties of Ethanol
i.
Combustion of Ethanol
Ethanol burns with a pale blue, non-luminous flame to form carbon dioxide
and steam.
C2H5OH + 3O2
2CO2 + 3H2O
Ethanol
ii.
Oxidation of Ethanol
Ethanol is oxidised
with acidified Potassium Dichromate, K2Cr2O7, or
with acidified Sodium Dichromate, Na2Cr2O7, or
with acidified potassium permanganate, KMnO4,
to form ethanal, (i.e. acetaldehyde).
[O]
C2H5OH
CH3CHO + H2O
Ethanol
Ethanal
The ethanal is further oxidised to ethanoic acid (i.e. acetic acid) if the
oxidising agent is in excess.
[O]
CH3CHO
Ethanal
CH3COOH
Ethanoic Acid
The oxidising agent usually used for this reaction is a mixture of sodium
dichromate or potassium dichromate and sulphuric acid which react together
to provide oxygen atoms as follows.
Na2Cr2O7 + 4 H2SO
iii.
4
Na2SO4 + Cr2(SO4)3 + 4H2O + 3[O]
Dehydration of Ethanol
When ethanol is mixed with concentrated sulphuric acid with the acid in
excess and heated to 170oC, ethylene is formed. (One mole of ethanol loses
one mole of water)
25

26. H2SO4
+
C2H5OH
170 oC
C2H4 + H2O
When ethanol is mixed with concentrated sulphuric acid with the alcohol in
excess and heated to 140 degC, diethyl ether distils over (two moles of ethanol
loses one mole of water) .
H2SO4
+
C2H5OC2H5 + H2O
140 deg
2 C2H5OH
iv.
Reaction of Ethanol with Sodium
Sodium reacts with ethanol at room temp to liberate hydrogen. The
hydrogen atom of the hydroxyl group is replaced by a sodium atom, forming
sodium ethoxide.
C2H5OH + Na
C2H5ONa + (H2)
Apart from this reaction, ethanol and the other alcohols show no acidic
properties.
v.
Dehydrogenation of Ethanol:
Ethanol can also be oxidised to ethanal (i.e. acetaldehyde) by passing its
vapour over copper heated to 300oC. Two atoms of hydrogen are eliminated
from each molecule to form hydrogen gas and hence this process is termed
dehydrogenation.
C2H5OH
Ethanol
CH3CHO + H2
Ethanal
26

27. vi.
Esterification of Ethanol:
Ethanol, C2H5OH, reacts with organic acids to form esters.
H(+)
C2H5OH +
Ethanol
vii.
CH3COOH
Ethanoic
Acid
CH3COOC2H5 + H2O
Ethyl
Water
Acetate
Halogenation or Substitution of Ethanol with PCl5 :
Ethanol reacts with phosphorus pentachloride at room temperature to form
hydrogen chloride, ethyl chloride (i.e. chloroethane) and phosphoryl chloride.
C2H5OH +
Ethanol
PCl5
Phosphorus
Pentachloride
C2H5Cl +
Ethyl
Chloride
POCl3 +
Phosphorus
Pentachloride
HCl
Hydrogen
Chloride
viii. Halogenation or Substitution of Ethanol with HCl:
Ethanol reacts with hydrogen chloride to form ethyl chloride (i.e.
chloroethane) and water. A dehydrating agent (e.g. zinc chloride) is used as
a catalyst.
ZnCl2
+
C2H5OH +
Ethanol
HCl
C2H5Cl + H2O
Ethyl
Chloride
27

28. 11.Uses of Ethyl Alcohol:
i.
As a fuel:
The largest single use of ethanol is as a motor fuel and fuel additive. Ethanol
may also be utilized as a rocket fuel, and is currently in lightweight rocketpowered racing aircraft. The US uses Gasohol (max 10% ethanol) and E85
(85% ethanol) ethanol/gasoline mixtures.
ii.
Antiseptic:
Ethanol is used in medical wipes and in most common antibacterial hand
sanitizer gels at a concentration of about 62% v/v as an antiseptic. Ethanol kills
organisms by denaturing their proteins and dissolving their lipids and is
effective against most bacteria and fungi, and many viruses, but is ineffective
against bacterial spores.
iii.
Feed stock:
Ethanol is an important industrial ingredient and has widespread use as a base
chemical for other organic compounds. These include ethyl halides, ethyl esters,
diethyl ether, chloroform, iodoform, acetic acid, ethyl amines, and, to a lesser
extent, butadiene.
iv.
Treatment for poisoning by other alcohols:
Ethanol is sometimes used to treat poisoning by other, more toxic alcohols, in
particular methanol and ethylene glycol. Ethanol competes with other alcohols
for the alcohol dehydrogenase enzyme, lessening metabolism into toxic
aldehyde and carboxylic acid derivatives, and reducing one of the more serious
toxic effect of the glycols to crystallize in the kidneys.
v.
Solvent:
Ethanol is miscible with water and is a good general purpose solvent. It is found
in paints, tinctures, markers, and personal care products such as perfumes and
deodorants.
vi.
It is used in scientific instruments such as thermometers and spirit levels.
vii.
It is used in manufacture of alcoholic beverages.
viii.
It is used as antifreeze in automobile radiators.
ix.
It is used as a preservative for biological specimens.
28

29. 12. Different Grades of Ethyl Alcohol:
Ethyl alcohol is one of the most important raw materials which are quite
frequently used. It is solid in different grades of purity for different purposes.
These are described below:
i.
Absolute alcohol:
It is the 100% pure ethanol. The fermentation of carbohydrates gives
ethanol containing water. The fractional distillation of aqueous solution of
ethanol gives a constant boiling azeotropic mixture which contains 95%
ethanol. To get 100% ethanol a small amount of benzene is added with
azeotropic mixture and then distilled. The first fraction (at 337.8 K) consists
of water, ethanol and benzene. After all water is removed, the second
fraction (at 341.2 K) consists of benzene and ethanol. Finally, pure ethanol
is distilled as the last fraction (351.1 K).
ii.
Methylated spirit or denatured alcohol:
It is a 95% ethyl alcohol. To avoid the misuse of alcohol meant for
industries for drinking purposes, it is made unfit by adding methanol,
pyridine etc. the process is called denaturing of alcohol and the alcohol,
thus obtained is called methylated spirit and can be used for non drinking
purposes and particularly in industries.
iii.
Power alcohol:
It is a mixture of 20% ethanol and 50% gasoline. Since alcohol does not
mix with petrol therefore a third solvent such as benzene, ether or
(tetrahydronapthalene) is added. Due to the increased world consumption of
petrol generally remains in a short supply. The use of power alcohol as a
substitute for gasoline has promised bright future in India because we can
manufacture large quantities of alcohol from molasses.
iv.
Alcoholic Beverages:
Liquors used for drinking purpose contain alcohol as the principal
intoxicating agent. These are also called alcoholic beverages. They are
prepared from different substance and contain different percentages of
alcohol. There are mainly two types of beverages: distilled and undistilled.
Undistilled beverages are prepared from grapes and other fruits juices and
are called wines. The liquors obtained by distillation have higher alcoholic
contents and have different trade names such as whisky, rum, brandy, gin,
etc.
29

30. 13. By-Products in Ethyl Alcohol production:
Plants that produce ethanol, corn oil, and corn sweeteners also produce byproducts in large quantities, and these by-products are employed successfully
by beef producers as a more affordable feed alternative for cattle.
i.
Carbondioxide (CO2) is a co-product of drymill ethanol production. Carbon
dioxide is present during the fermentation stage of ethanol production, and
many ethanol plants collect that carbon dioxide and market it as co-product.
The carbon dioxide is cleaned of any residual alcohol, compressed, and sold to
other industries. Carbon dioxide is used to carbonate beverages, to
manufacture dry ice, and to flash freeze meat. CO2 is also used by paper mills
and other food processors.
ii.
Dried Distillers Grain ( DDG):
Distillers grain is an important co-product of drymill ethanol production.
Drymill ethanol production process uses only the starch portion of the corn,
which is about 70% of the kernel. All the remaining nutrients - protein, fat,
minerals, and vitamins - are concentrated into distillers grain, a valuable feed
for livestock
It is created from drying the mash after all useful ethanol has been extracted it
is used as feed for cattle. Also DDGS is a soluble version made by adding
water which is more easily consumed by cattle. “DDGS is a high quality
feedstuff ration for dairy cattle, beef cattle, swine poultry,and aquaculture.
iii.
Straw is another important co-Product from cereals and has been used for
centuries for various uses. It has mostly been used for animal feed although
recent uses include bio fuels in the lignocellulosic path to bioethanol. It can be
used as a substrate for bio gas production through anaerobic digestion.
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31. 31

32. BIBLIOGRAPHY
1. Laboratory manual on Environmental Engineering prepared by
Sri P.V.L.N. SIVA PRASAD (Head of Chemical Engineering).
Sri P. KRISHNA REDDY (Lecture in Chemical Engineering).
At N.I.T.T.T & R, Chennai.
2. Dryden’s Outline of Chemical Technology 3rd edition by,
M.GOPALA RAO,
MARSHALL SITIG
East West Press.
3. Modern’s ABC of Chemistry by,
Dr. S.P. JAUHAR,
Modern Publishers.
4. Shreve’s Chemical Process Industries, 5th edition by,
GEORGE T. AUSTIN,
Mc-Grawhill Book Company.
5. A Project Report on “Design and Fabrication of Conventional Hydrogenator”
submitted by,
2009 Batch DCHE (OT) students.
6. Browsing and edited from Internet source by,
M.NIRMAL KUMAR (10065-CHOT-028)
B.V.SUDHEER (10065-CHOT-007)
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