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MEDICAL BIOCHEMISTRY DEPARTMENT
OPURUM H. C
ALCOHOLS
1
Organic Chemistry
(MBC 233.1)
1
Learning Objectives
ØUnderstanding
ØWhat Alcohols are
ØSynthesis of alcohols
ØReactions of alcohols
Ø Uses of Alcohol In Daily Life,
Medicines, Pharmacy
2
2
ALCOHOLS
vAlcohols are hydroxy‐substituted alkanes, alkenes,
or alkynes in which the substitution occurs on a
saturated carbon.
vThe general formula for alcohols is R-OH, where
the R group can represent the alkyl, alkenyl, or
alkynal groups.
vIn the case of substitution on alkenes and alkynes,
only saturated carbons may be substituted.
•
3
v For example, the following compounds are all alcohols:
v
v
v If the hydroxyl group were substituted for a hydrogen on an
unsaturated carbon, an alcohol would not form.
v For example, substituting the hydroxyl group for a terminal
hydrogen of 1‐propene gives an unstable enol that
tautomerizes to a ketone.
•
4
Nomenclature
v You can use both the common and IUPAC systems to name
alcohols.
v In the common system, you name an alcohol by listing the
alkyl group and adding the word alcohol.
v Following are some examples of alcohols and their common
names:
v
•
5
In the IUPAC system, use the following series
of rules to name alcohols:
1. Pick out the longest continuous chain to which the hydroxyl
group is directly attached.
1. The parent name of the alcohol comes from the
alkane name for the same chain length.
2. Drop the ‐e ending and add ‐ol.
2. Number the parent chain so that the carbon bearing the
hydroxyl group has the lowest possible number.
1. Place the number in front of the parent name.
3. Locate and name substituents other than the hydroxyl
group.
6
The following examples show how you apply
these rules:
v You may classify alcohols as primary (1°), secondary
(2°), or tertiary (3°), based on the class of carbon to
which the hydroxyl group (R-OH) is directly bonded.
v For example,
1 propanol is a
‐ 1° alcohol, 2 propanol is a
‐ 2° alcohol,
and 2 methyl 2 propanol is a
‐ ‐ ‐ 3° alcohol.
7
Physical properties
v Alcohols contain both a polar —OH group and a nonpolar alkyl
group.
v As a result of this composition, alcohols that have small alkyl
chains tend to be water soluble.
v As alkyl chain length increases, water solubility decreases.
v Through the OH group, alcohols are capable of forming
hydrogen bonds to themselves, other alcohols, neutral
molecules, and anions.
v This bond formation leads to abnormally high boiling points
compared to other organic molecules of similar carbon chain
length.
•
8
Synthesis of Alcohols
9
Synthesis of Alcohols
vAlcohols can be prepared by the
hydration of alkenes or by the
reduction of aldehydes, ketones,
acids, & esters.
10
Hydration of alkenes
vThe elements of water can be added to the double‐
bonded carbons of an alkene in either a
Markovnikov's or an anti‐Markovnikov's manner.
vAs shown in the following figure, a hydrogen ion
catalyzes the Markovnikov's addition.
•
11
v The anti‐Markovnikov's addition results from a hydroboration‐
oxidation reaction.
v
v Reduction of aldehydes and ketones
v
v
v
v
v
v An aldehyde has a structural formula of
v
v
v while the structural formula of a ketone is
12
vIn these formulas, the R or R′ group may be
either an aliphatic or aromatic group.
vIn a ketone, the R and R′ groups may
represent the same group or different
groups.
vThese types of compounds are best reduced
by complex metal hydrides, such as lithium
aluminum hydride (LiAlH4) or sodium
borohydride (NaBH4).
13
Two examples of complex metal reductions:
ØLithium aluminum hydride is a very strong reducing
agent that will reduce many functional groups in
addition to aldehydes and ketones.
ØSodium borohydride is a much weaker reducing agent
that basically will reduce only aldehydes and ketones to
alcohols.
14
o You can also catalytically reduce aldehydes and
ketones to produce 1° and 2° alcohols.
o Reduction conditions are very similar to those
used to reduce alkene double bonds.
o If a molecule possesses both a double bond and
an aldehyde or ketone functional group,
reduction of the aldehyde or ketone group is
best carried out using sodium borohydride.
15
o The reduction of cyclohexanone by hydrogen
gas with a platinum catalyst produces
cyclohexanol in good yield.
16
Reduction of carboxylic acids
o The reduction of a carboxylic acid:
o
o leads to the formation of a primary alcohol:
o
o
o This reduction requires a very strong reducing agent, and lithium
aluminum hydride is the standard choice.
o
•
17
o Diborane, B2H6, also reduces carboxylic
acids to alcohols.
o
o
o
o
o Catalytic hydrogenation gives very poor yields
and is not usually used for this type of
reaction.
18
Reduction of esters
Ø Esters, like carboxylic acids, are normally reduced with
lithium aluminum hydride.
Ø In these reactions, two alcohols are formed. An
example is the reduction of methyl benzoate to
benzyl alcohol and methanol.
Ø
•
19
Grignard reaction with aldehydes and ketones
Ø The Grignard reaction is the only simple method available that is
capable of producing primary, secondary, and tertiary alcohols.
Ø To produce a primary alcohol, the Grignard reagent is reacted with
formaldehyde.
Ø
•
20
Ø Reacting a Grignard reagent with any other aldehyde
will lead to a secondary alcohol.
Ø
Ø
•
Ø Finally, reacting a Grignard reagent with a ketone will
generate a tertiary alcohol.
Ø
21
Reactions
of
Alcohols
22
22
qAlcohols are capable of being
converted to:
q metal salts,
q alkyl halides,
q esters,
q aldehydes,
q ketones,
q carboxylic acids.
23
23
Metal salt formation
• Alcohols are only slightly weaker acids than
water, with a Ka value of approximately
1×10−16.
• The reaction of ethanol with sodium metal (a
base) produces sodium ethoxide and hydrogen
gas.
This reaction is identical to the reaction of
sodium metal with water.
24
24
vHowever, the latter reaction occurs faster because of
the increased acidity of water (K a value of 1 × 10 −15).
vLikewise, similar reactions occur with potassium metal.
vThe acidity of alcohols decreases while going from
primary to secondary to tertiary.
vThis decrease in acidity is due to two factors:
v an increase of electron density on the oxygen atom
of the more highly‐substituted alcohol, and
v steric hindrance (because of the alkyl groups, which
inhibit solvation of the resulting alkoxide ion).
25
25
vBoth of these situations increase the activation
energy for proton removal.
vThe basicity of alkoxide ions increases while going
from primary to tertiary.
vThis increase in basicity occurs because the
conjugate base of a weak acid is strong.
vThe weaker the acid, the stronger the conjugate
base.
26
26
Alkyl halide formation
§ Alcohols are converted to alkyl halides by
S N1 and S N2 reactions with halogen
acids.
§
Primary alcohols favor S N2 substitutions while
S N1 substitutions occur mainly with tertiary
alcohols. 27
27
§ A more efficient method of preparing alkyl halides from
alcohols involves reactions with thionyl chloride
(SOCl 2).
•
•
§ This reaction is rapid and produces few side reaction
products.
§ In addition, the sulfur dioxide and hydrogen chloride
formed as byproducts are gasses and therefore easily
removed from the reaction.
§ Mechanistically, the alcohol initially reacts to form an
inorganic ester.
28
28
The chloride ion produced by this reaction, acting as a
nucleophile, attacks the ester in an S N2 fashion to yield
molecules of sulfur dioxide, hydrogen chloride, and an alkyl
halide.
Because the reaction proceeds mainly by an S N2 mechanism, the
alkyl halide produced from an optically active alcohol will have
the opposite relative configuration from the alcohol from which it
was formed.
29
29
Because thionyl bromide is relatively unstable, alkyl
bromides are normally prepared by reacting the alcohol with
phosphorous tribromide (PBr 3).
30
30
This reaction proceeds via a two step mechanism.
‐
In the first step, the alcohol reacts with the phosphorous
tribromide.
The second step is an S N1 or S N2 substitution in which
the bromide ion displaces the dibromophosphorous
group.
In a similar manner, alkyl iodides are
prepared by reacting an alcohol with
phosphorous triiodide.
31
31
32
Ester formation
§ Esters are compounds that are commonly
formed by the reaction of oxygen‐containing
acids with alcohols.
§ The ester functional group is the
§
§ Alcohols can be converted to esters by means of the
Fischer Esterification Process.
§ In this method, an alcohol is reacted with a
carboxylicacid in the presence of an inorganic
acid catalyst.
33
33
§ Because the reaction is an equilibrium reaction,
in order to receive a good yield, one of the
products must be removed as it forms.
§ Doing this drives the equilibrium to the product
side.
§
34
34
•The mechanism for this type of reaction takes
place in seven steps:
•1. The mechanism begins with the protonation of
the acetic acid.
•
The π electrons of the carboxyl group, ,
migrate to pick up the positive charge.
35
35
3. The oxygen of the alcohol molecule attacks the carbocation.
•
•
4. The oxonium ion that forms loses a proton.
•
•
5. One of the hydroxyl groups is protonated to form an oxonium ion.
•
•
•
36
36
6. An unshared pair of electrons on another hydroxy group re-
establishes the carbonyl group, with the loss of a water molecule.
•
•
7. The oxonium ion loses a proton, which leads to the production of the
ester.
37
37
§ Alkyl sulfonate formation.
§ Alcohols may be converted to alkyl sulfonates, which
are sulfonic acid esters.
§ These esters are formed by reacting an alcohol with
an appropriate sulfonic acid.
§ For example, methyl tosylate, a typical sulfonate, is
formed by reacting methyl alcohol with tosyl
chloride.
38
38
• Other sulfonyl halides that form alkyl sulfonates include:
•
39
39
§ These groups are much better leaving groups
than the hydroxyl group because they are
resonance stabilized.
§ Alcohol molecules that are going to be reacted
by S N1 or S N2 mechanisms are often first
converted to their sulfonate esters to improve
both the rate and yield of the reactions.
40
40
Formation of aldehydes and ketones.
§ The oxidation of alcohols can lead to the
formation of aldehydes and ketones.
§ Aldehydes are formed from primary alcohols,
while ketones are formed from secondary
alcohols.
§ Because you can easily further oxidize aldehydes
to carboxylic acids, you can only employ mild
oxidizing agents and conditions in the formation
of aldehydes. 41
41
•Typical mild oxidizing agents include manganese
dioxide (MnO2), Sarett‐Collins reagent
(CrO3(C 5H 5N) 2), and pyridinium
chlorochromate (PCC).
•
42
42
•Examples of the oxidation of primary alcohols:
•
43
43
vBecause ketones are more resistant to
further oxidation than aldehydes, stronger
oxidizing agents and higher temperatures
may be employed.
vSecondary alcohols are normally converted
to ketones by reaction with potassium
dichromate (K2Cr2O7), potassium
permanganate (KMnO4), or chromium
trioxide in acetic acid (CrO3/CH3COOH).
44
44
•Examples of the oxidation of secondary alcohols
•
•
45
45
Carboxylic acid formation.
vUpon oxidation with strong oxidizing agents
and high temperatures, primary alcohols
completely oxidize to form carboxylic acids.
vThe common oxidizing agents used for these
conversions are concentrated potassium
permanganate or concentrated potassium
dichromate.
46
46
•Examples of this type of oxidation:
•
47
47
The Alcohol Reaction Map
vEther formation via substitution reactions
vElimination of alcohols to form alkenes
vConversion of alcohols to alkyl halides via
substitution reactions
vCleavage of ethers
vOpening of epoxides
vReactions of thiols
• 48
49
Uses of Alcohol In
Daily Life,
Medicines,
Pharmacy
50
Uses of Alcohol:
•There are different types of alcohol with different
uses.
•The various types of alcohols and their uses range
in applications from medicine to cooking.
•During the coronavirus pandemic, sanitisers and
masks rose to fame overnight.
•Hand sanitizers contain 99.5% alcohol.
• The alcohol present in sanitizers is isopropyl alcohol.
51
52
METHANOL
1. As a Chemical Feedstock
• Methanol is widely used as a chemical feedstock in the production of
methanal or formaldehyde by catalytic oxidation.
• It is also used in the manufacture of acetic acid.
• Formaldehyde or HCHOHCHO is used in the manufacture of plastics, paints,
explosives, textiles and cosmetics.
2. As a Solvent
• Methanol is used as a solvent for inks, adhesives, resins and dyes.
• Methanol is often added to ethanol to discourage overconsumption of
alcohol.
• It is also used as a solvent in the pharmaceutical industry.
• It is used in antifreeze for automotive radiators and screen-wash.
• 53
Methanol (CH3OH)
3. As a Fuel
• Methanol is used as an additive in petrol to improve combustion.
• It can be used as a fuel in several internal combustion engines.
• The equation for the combustion of methanol is given by-
2CH3OH+3O2→4H2O+2CO22CH3OH+3O2→4H2O+2CO2
Biodiesel
• Biodiesel is produced by reacting vegetable oils with methanol.
• The main product is a methyl ester of a long-chain fatty acid, which is used as
biodiesel.
• Glycerol is produced as a by-product in the reaction.
• Biodiesel can be used as a replacement fuel in most modern diesel engines.
54
Advantages:
• Methanol can be stored easily compared to hydrogen gas or natural gas.
• It is biodegradable and has a very short half-life in groundwater.
• Methanol easily blends with gasoline/diesel and has the potential to
substitute them altogether.
• Methanol as fuel is cleaner than gasoline or LPG. Hence, methanol cook-
stoves can help in achieving the objective of access to clean cooking fuels.
Disadvantages:
• Methanol tends to corrode aluminum and some other metals.
• Its energy density is approximately half of the energy density offered by
gasoline.
55
Ethanol (C2H5OH)
56
1. As an Ingredient in Alcoholic Beverages
• Ethanol (or ethyl alcohol) is the type of alcohol that over two billion people
drink every day.
• This type of alcohol is produced by the fermentation of yeast, sugars, and
starch.
• The human liver can metabolise ethanol, but only in limited quantities.
• There are two categories of alcoholic beverages:
a. Distilled alcohol:
• Distillation converts a fermented substance into another substance with an
even higher concentration of alcohol.
• It concentrates alcohol by separating it from the water and other components
of a fermented substance.
• Liquors and spirits are distilled alcoholic beverages.
• They contain more alcohol by volume than undistilled drinks.
• In general, a distilled alcoholic beverage will have a higher alcohol proof.
57
b. Un-distilled alcohol:
• Un-distilled alcohols are also called fermented drinks.
• Fermentation is the process by which bacteria or yeast
chemically converts sugar into ethanol.
• Wine and beer are both fermented, un-distilled
alcoholic beverages.
• Wineries ferment grapes to make wine, and breweries
ferment barley, wheat, and other grains to make beer.
58
2. To Produce Methylated Spirit (meth)
• To discourage the over-consumption of alcohol, ethanol
is often mixed with methanol.
• This process is known as Denaturing of ethanol.
• The resulting mixture is also called methylated spirit,
which is poisonous, making ethanol unfit for
consumption.
• Methylated spirit is combustible; hence it can be used
in lamps and stoves made for camping.
• Methylated spirit is used to remove ink from various
kinds of surfaces, such as metals and plastics.
• Methylated spirit is used as a component of household
cleaning products, usually glass cleaners.
• 59
3. As a Solvent
• Ethanol is used as a solvent to dissolve many organic
compounds that are insoluble in water.
• It is used in perfumes, cosmetics, paints, detergents and inks.
• Ethanol has antibacterial properties as it slows or stops the
growth of micro-organisms (germs).
• It alters the shapes of proteins in the micro-organisms
preventing them from functioning effectively.
• The denaturation of proteins happens when the bonds that
hold the protein together to maintain its specific shape are
broken.
• For this reason, ethanol is used in hand sanitisers and hand
wipes.
60
•Ethanol (in concentrations ranging
from 1% to 25%) is used as a solvent for some
analgesics and mouthwashes.
•Since it has a melting point of –114.1oC, ethanol is
used as an ingredient in cooling baths in several
laboratories.
•It also serves as the active fluid in many spirit
thermometers.
•
61
4. Used as a Fuel
• Ethanol acts as a clean fuel because it undergoes
complete combustion. It burns with a clean,
smokeless flame to produce carbon dioxide and water.
• 2C2H5OH+6O2→6H2O+4CO22C2H5OH+6O2→6H2O+4CO2
• Ethanol is usually mixed with gasoline to produce
‘gasohol”, which is about 10% ethanol.
• Using ethanol as a fuel reduces our dependency on natural fossil fuels
such as petrol. In countries like Brazil with limited natural oil supplies,
sugar cane is grown on a large scale. Fermentation of sugar cane is
carried out to produce ethanol. The ethanol produced by
fermentation is used as an alternative source of fuel.
62
• Using ethanol as a fuel reduces our dependency on
natural fossil fuels such as petrol.
• In countries like Brazil with limited natural oil supplies,
sugar cane is grown on a large scale.
• Fermentation of sugar cane is carried out to produce
ethanol.
• The ethanol produced by fermentation is used as an
alternative source of fuel.
• Ethanol combustion produces carbon dioxide that
returns to the atmosphere and is used by the green
plants to produce glucose necessary for ethanol
fermentation.
•
63
64
Disadvantages of Bioethanol
•The demand for biofuel crops means greater
demand on rainforest land.
•This leads to clearing rainforests into agricultural
land, which may not consume carbon dioxide as
efficiently as rainforests do.
•The conditions required for growing biofuel crops
may not be adequate in many parts of the world.
•This discrepancy would not satisfy the demand for
fuel.
65
Disadvantages of Bioethanol cont’d
•Modern petrol engines cannot use biofuels. Therefore,
modification in petrol engines would lead to
additional manufacturing costs.
•Although biofuels are theoretically carbon-neutral, this
does not account for the carbon dioxide emissions
associated with growing, harvesting and transporting
the crops or producing ethanol.
•Therefore, overall, more carbon dioxide is emitted than
is absorbed, which means that it contributes to global
warming.
•Using food crops to produce fuels, could cause food
shortages or increases in food prices.
•
66
Propanol (CH3CH2CH2OH)
•Propanol is short-chain alcohol with three C atoms.
•11-propanol (nn-propyl alcohol, 11-propyl alcohol,
or nn-propanol ) has a linear structure, whereas 22-
propanol or isopropanol are branched.
•Due to their properties (high volatility, rapid effect,
and low toxicity), both 11-propanol and 22-propanol
are often used in hand disinfectants because of their
have excellent bactericidal activity.
•
67
1. As a Solvent / Intermediate
• Propanol is used as a solvent to produce other
solvents such as antifreeze, lacquer formulations,
soaps, dye solutions, window cleaner and more.
• Propanol like isopropanol or isopropyl alcohol is most
commonly used in the printing industry, especially
flexographic ink.
• It is used as a cleansing agent in floor polishes and
metal degreasers.
• Propanol acts as a chemical intermediate in the
process of creating halides, propyl amines and propyl
acetate.
68
2. Medical Use
• Propanol exhibits antibacterial properties.
• Rubbing alcohol and sanitisers contain isopropyl alcohol.
• It is also used as a depressant or pain reliever.
• It is found in alcoholic beverages as a by-product of fermentation.
3. Cosmetics
• Propanol is used in different cosmetics, e.g. acetate is used as a
remover for acrylic nails and fingernail polish. It is also used in
perfumes.
4. As a Fuel
• Propanol has a high octane number and is quite suitable for
engine fuel usage. However, its manufacturing process is not
economical.
69
Butanol (CH3CH2CH2CH2OH)
• nn-butanol, also known as 11-butanol, or butyl alcohol, is four-carbon
linear chain alcohol.
• It is produced by petrochemical processes or fermentation of sugars
derived from corn.
1. In the Manufacturing Industry
• Butanol is primarily used to manufacture plastics, polymers, lubricants,
brake fluids, and synthetic rubber.
• Butanol is an environment friendly and powerful solvent for cleaning and
polishing products.|
• Butanol can also be used as a fuel.
• nn-Butanol is present in numerous beverages and food, and it is used as
an artificial food flavouring agent.
70
2. In Cosmetic and Laboratory Industry
• Butanol is used as a humectant for cellulose nitrate
• It is used as a chemical feedstock for butyl ethanoate, a synthetic food
flavouring agent in the food and confectionary industry.
• They are used in the cosmetic industry in products such as shampoo, shaving
products and soaps.
• It is used as a chemical intermediate to create other vital compounds such as
Glycol Ether, Acrylate Esters, Amino Resins, Acetates, and Amines.
3. As a Source of Fuel
• nn-butanol has a higher energy content than ethanol.
• It is more compatible with the gasoline structure and does not absorb water
from ambient air.
• Biobutanol can be used as a transportation fuel.
Uses of Alcohols in Pharmacy
• Doctors, nurses and medical practitioners disinfect their hands in alcoholic
solutions before handling patients.
• During surgery, the surgical area is cleaned with alcohol to stem infections.
71
How is alcohol used in
life-saving situations in
the medical field.
72
1. Wound Dresser
• Earlier, alcohol was used as an antiseptic, poured over wounds, and
antidote for snake bites.
• In addition, patients were given a drink of whiskey before an operation.
More recently, alcohol is used as a mild sedative.
2. Cough and Cold Remedy
• Alcohols are a popular cough remedy commodity.
• It is believed to clear minor colds and congestion and is found in most
cough syrups.
3. Hand Disinfectant
• It is the most common use of alcohol in recent times.
• Alcohols exhibit antifungal, antibacterial properties.
• It is used as a disinfectant where soap and water are not readily
available.
73
4. As a Local Rubefacient
• Alcohol is applied to the skin to dilate blood vessels. As a result, the skin area becomes tender and
absorbent to medicinal ointment application.
5. Used as a Diluent
• Alcohols act as a diluent for many drugs, especially in homoeopathy treatment.
• A small number of drugs can be diluted in low quantities of alcohol.
• In these low quantities, alcohol is harmless to the body and increases the drug’s volume.
6. Used as a Solvent
• Alcoholic ethanol is an excellent solvent for many drugs as it increases the concentration of solid
drug matter.
• This can also be used for filtration, distillation, and removal of impurities from the drug.
7. Used as a Pain Reliever
• Alcohol is used as a pain reliever to abate acute pain. For example, in cancer patients, alcohol is
usually injected near the affected area to deaden the nerve endings. This leads to pain reduction.
8. As an Antiseptic
• Alcohol is used to sterilise medical equipment like injections needles, surgical blades, forceps, etc.
• Alcohol acts as an antiseptic to clean scratches and mild wounds.
9. As a Preservative
• In the laboratory, plant and animal specimens are usually preserved in alcohol.
• This is because the bactericidal properties of alcohol destroy microbes and other harmful bacteria.
74
10. Crystallisation and Extraction
• Alcohol is employed for the extraction of active ingredients from plants and other specimens.
• The extraction is done by steam distillation. Due to the low boiling point, alcohol quickly
evaporates and then percolates through the solid material.
• Alcohol is also used in the crystallisation of compounds which is an essential step in the
purification process.
11. As a Cleaning Agent
• Alcohol is used as a cleaning agent in hospitals and medical facilities, and cleaning laboratories
to eliminate microbial contamination.
12. Laboratory Staining
• While carrying out experiments on plant tissue and animal tissue, staining of the specimen is
essential. This staining is done with alcohol that helps highlight the specimen under the
microscope.
13. Solvent for Analysis
• Chemistry analytical processes like Chromatography analysis use Ethanol, Methanol, and
Isopropanol as solvent.
• Alcohol plays a vital role in the separation process using these analytical techniques.
14. Lighting Laboratories
• Laboratories use ethanol lamps to light up. Ethanol burns cleanly and does not leave soot.
75
Uses of Alcohol in Medicine and Pharmacology
• Alcohol is an essential ingredient in medicines like cough syrups, respiratory treatment drugs. Pain
relievers also contain a high percentage of alcohol. Here is a list of several drugs that have alcohol as an
essential ingredient.
1. Amoxicillin Trihydrate
• Amoxicillin is used to treat bacterial infection and endocarditis prevention. It treats anthrax prophylaxis,
actinomycosis, and dental abscess. It contains alcohols, isopropanol, and propanediol as active
ingredients.
2. Atazanavir Sulfate
• Atazanavir contains isopropyl alcohol and propylene glycol, which is used in the treatment of HIV
infections.
3. Bupropion Hydrochloride
• Bupropion acts as a miscellaneous antidepressant used in the treatment of depressive disorders.
4. Phentermine Hydrochloride
• Phentermine used in the treatment of obesity contains isopropyl alcohol, butyl alcohol, and propylene
glycol.
5. Temazepam
• Temazepam is used in the treatment of insomnia, and it contains isopropyl alcohol and butyl alcohol.
76
6. Tizanidine Hydrochloride
• Tizanidine is a relaxant used in the treatment of muscle spasm. It contains
isopropyl alcohol and butyl alcohol.
7. Zonisamide
• Zonisamide is an inhibitor anticonvulsant that contains isopropyl alcohol
and butyl alcohol. It is used in the treatment of seizures.
• 8. Benadryl
• Benadryl is an antihistamine used to relieve symptoms of allergy, hay fever,
and the common cold. It contains alcohol, isopropyl alcohol, butyl alcohol.
• 9. Codimal DM
• Codimal is used to treat symptoms caused by the common cold, flu,
allergies, or other breathing illnesses. It has isopropyl alcohol and butyl
alcohol.
• 10. Decaprin
• It is a combination of drug-containing expectorants and nasal decongestants
used to treat cough and nasal congestion. It contains isopropyl alcohol
and butyl alcohol.
77
11. Vicks Cough 5.0%
• Vicks cough contains alcohol used for the temporary treatment of cough, blocked
nose, sinus pressure caused by infection or other breathing illnesses.
12. Anbesol Gel
• Anbesol Gel contains benzocaine and is used as a local anaesthetic. It blocks nerve
endings and numbs the skin and mouth surface. Anbesol Gel is made of
almost 70% alcohol.
13. Dent’s Toothache Drops
• Dent’s Toothache Drops are used to lessen toothache pain. It comprises almost 60%
alcohol.
14. Dental Gel
• Corsodyl Dental Gel is used to treat gum disease, control recurring mouth ulcers,
prevent cavities and maintain mouth hygiene. It is made of 7.5% alcohol.
15. Toothache Drops
• Tooth Drops have almost 20% alcohol and Benzocaine.
• It is used for toothache, canker sores, sore gums, throat, mouth, and gum injury.
• It is a local anaesthetic that works by numbing the painful place.
78
Uses of Alcohols and Hydrocarbons
•The major difference between an alcohol and a
hydrocarbon is that alcohol has a hydroxyl
functional group (–OH) bound to a saturated
carbon atom and hydrocarbon is an organic
compound consisting entirely of hydrogen and
carbon.
•Hydrocarbons are the principal constituents of
petroleum and natural gas. They serve as fuels
and lubricants and are a precursor to the
production of plastics, fibres, rubbers, solvents,
explosives, and industrial chemicals.
79
Uses of Alcohols and Hydrocarbons
• Hydrocarbons are also found in plants, animals, and their
fossils.
• The familiar plastics polyethylene, polypropylene, and
polystyrene are also hydrocarbons.
• Polymers are large molecules of hydrocarbons made up
of repeating units, referred to as monomers.
• They can be natural such as starch, or synthetic, like
polyethylene, polyvinyl chloride (PVC), and polystyrene.
• Most of these plastics are recycled and reprocessed into
useful products.
• For example, soft drink bottles are melted down and used
for plastic furniture, carpets, or other applications.
•
80
Uses of Alcohol in the Human Body
•Moderate alcohol use has possible health
benefits, but it is not risk-free.
The potential benefits of alcohol are relatively
small and may not apply to all individuals.
•Therefore, one should not begin drinking alcohol
based on potential health benefits.
•For many people, the possible benefits do not
outweigh the risks and avoiding alcohol is the
best course.
81
What do you
think are some
risks associated
with alcohol use?
82
83
84
85
86
87
88
89
Alcohol Poisoning
•Occurs when drinking large
quantities of alcohol within a
short period of time
•Binge drinking (≥5 drinks/drinking
occasion)
•Depresses nerves that control
involuntary actions such as
breathing and the gag reflex.
90
91
DON’T DRINK & DRIVE!!!
DON’T DRINK & STUDY!!!!
DRINK RESPONSIBLY!!!!!!

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organic chemistry lecture module - alcohol.pdf

  • 1. MEDICAL BIOCHEMISTRY DEPARTMENT OPURUM H. C ALCOHOLS 1 Organic Chemistry (MBC 233.1) 1
  • 2. Learning Objectives ØUnderstanding ØWhat Alcohols are ØSynthesis of alcohols ØReactions of alcohols Ø Uses of Alcohol In Daily Life, Medicines, Pharmacy 2 2
  • 3. ALCOHOLS vAlcohols are hydroxy‐substituted alkanes, alkenes, or alkynes in which the substitution occurs on a saturated carbon. vThe general formula for alcohols is R-OH, where the R group can represent the alkyl, alkenyl, or alkynal groups. vIn the case of substitution on alkenes and alkynes, only saturated carbons may be substituted. • 3
  • 4. v For example, the following compounds are all alcohols: v v v If the hydroxyl group were substituted for a hydrogen on an unsaturated carbon, an alcohol would not form. v For example, substituting the hydroxyl group for a terminal hydrogen of 1‐propene gives an unstable enol that tautomerizes to a ketone. • 4
  • 5. Nomenclature v You can use both the common and IUPAC systems to name alcohols. v In the common system, you name an alcohol by listing the alkyl group and adding the word alcohol. v Following are some examples of alcohols and their common names: v • 5
  • 6. In the IUPAC system, use the following series of rules to name alcohols: 1. Pick out the longest continuous chain to which the hydroxyl group is directly attached. 1. The parent name of the alcohol comes from the alkane name for the same chain length. 2. Drop the ‐e ending and add ‐ol. 2. Number the parent chain so that the carbon bearing the hydroxyl group has the lowest possible number. 1. Place the number in front of the parent name. 3. Locate and name substituents other than the hydroxyl group. 6
  • 7. The following examples show how you apply these rules: v You may classify alcohols as primary (1°), secondary (2°), or tertiary (3°), based on the class of carbon to which the hydroxyl group (R-OH) is directly bonded. v For example, 1 propanol is a ‐ 1° alcohol, 2 propanol is a ‐ 2° alcohol, and 2 methyl 2 propanol is a ‐ ‐ ‐ 3° alcohol. 7
  • 8. Physical properties v Alcohols contain both a polar —OH group and a nonpolar alkyl group. v As a result of this composition, alcohols that have small alkyl chains tend to be water soluble. v As alkyl chain length increases, water solubility decreases. v Through the OH group, alcohols are capable of forming hydrogen bonds to themselves, other alcohols, neutral molecules, and anions. v This bond formation leads to abnormally high boiling points compared to other organic molecules of similar carbon chain length. • 8
  • 10. Synthesis of Alcohols vAlcohols can be prepared by the hydration of alkenes or by the reduction of aldehydes, ketones, acids, & esters. 10
  • 11. Hydration of alkenes vThe elements of water can be added to the double‐ bonded carbons of an alkene in either a Markovnikov's or an anti‐Markovnikov's manner. vAs shown in the following figure, a hydrogen ion catalyzes the Markovnikov's addition. • 11
  • 12. v The anti‐Markovnikov's addition results from a hydroboration‐ oxidation reaction. v v Reduction of aldehydes and ketones v v v v v v An aldehyde has a structural formula of v v v while the structural formula of a ketone is 12
  • 13. vIn these formulas, the R or R′ group may be either an aliphatic or aromatic group. vIn a ketone, the R and R′ groups may represent the same group or different groups. vThese types of compounds are best reduced by complex metal hydrides, such as lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4). 13
  • 14. Two examples of complex metal reductions: ØLithium aluminum hydride is a very strong reducing agent that will reduce many functional groups in addition to aldehydes and ketones. ØSodium borohydride is a much weaker reducing agent that basically will reduce only aldehydes and ketones to alcohols. 14
  • 15. o You can also catalytically reduce aldehydes and ketones to produce 1° and 2° alcohols. o Reduction conditions are very similar to those used to reduce alkene double bonds. o If a molecule possesses both a double bond and an aldehyde or ketone functional group, reduction of the aldehyde or ketone group is best carried out using sodium borohydride. 15
  • 16. o The reduction of cyclohexanone by hydrogen gas with a platinum catalyst produces cyclohexanol in good yield. 16
  • 17. Reduction of carboxylic acids o The reduction of a carboxylic acid: o o leads to the formation of a primary alcohol: o o o This reduction requires a very strong reducing agent, and lithium aluminum hydride is the standard choice. o • 17
  • 18. o Diborane, B2H6, also reduces carboxylic acids to alcohols. o o o o o Catalytic hydrogenation gives very poor yields and is not usually used for this type of reaction. 18
  • 19. Reduction of esters Ø Esters, like carboxylic acids, are normally reduced with lithium aluminum hydride. Ø In these reactions, two alcohols are formed. An example is the reduction of methyl benzoate to benzyl alcohol and methanol. Ø • 19
  • 20. Grignard reaction with aldehydes and ketones Ø The Grignard reaction is the only simple method available that is capable of producing primary, secondary, and tertiary alcohols. Ø To produce a primary alcohol, the Grignard reagent is reacted with formaldehyde. Ø • 20
  • 21. Ø Reacting a Grignard reagent with any other aldehyde will lead to a secondary alcohol. Ø Ø • Ø Finally, reacting a Grignard reagent with a ketone will generate a tertiary alcohol. Ø 21
  • 23. qAlcohols are capable of being converted to: q metal salts, q alkyl halides, q esters, q aldehydes, q ketones, q carboxylic acids. 23 23
  • 24. Metal salt formation • Alcohols are only slightly weaker acids than water, with a Ka value of approximately 1×10−16. • The reaction of ethanol with sodium metal (a base) produces sodium ethoxide and hydrogen gas. This reaction is identical to the reaction of sodium metal with water. 24 24
  • 25. vHowever, the latter reaction occurs faster because of the increased acidity of water (K a value of 1 × 10 −15). vLikewise, similar reactions occur with potassium metal. vThe acidity of alcohols decreases while going from primary to secondary to tertiary. vThis decrease in acidity is due to two factors: v an increase of electron density on the oxygen atom of the more highly‐substituted alcohol, and v steric hindrance (because of the alkyl groups, which inhibit solvation of the resulting alkoxide ion). 25 25
  • 26. vBoth of these situations increase the activation energy for proton removal. vThe basicity of alkoxide ions increases while going from primary to tertiary. vThis increase in basicity occurs because the conjugate base of a weak acid is strong. vThe weaker the acid, the stronger the conjugate base. 26 26
  • 27. Alkyl halide formation § Alcohols are converted to alkyl halides by S N1 and S N2 reactions with halogen acids. § Primary alcohols favor S N2 substitutions while S N1 substitutions occur mainly with tertiary alcohols. 27 27
  • 28. § A more efficient method of preparing alkyl halides from alcohols involves reactions with thionyl chloride (SOCl 2). • • § This reaction is rapid and produces few side reaction products. § In addition, the sulfur dioxide and hydrogen chloride formed as byproducts are gasses and therefore easily removed from the reaction. § Mechanistically, the alcohol initially reacts to form an inorganic ester. 28 28
  • 29. The chloride ion produced by this reaction, acting as a nucleophile, attacks the ester in an S N2 fashion to yield molecules of sulfur dioxide, hydrogen chloride, and an alkyl halide. Because the reaction proceeds mainly by an S N2 mechanism, the alkyl halide produced from an optically active alcohol will have the opposite relative configuration from the alcohol from which it was formed. 29 29
  • 30. Because thionyl bromide is relatively unstable, alkyl bromides are normally prepared by reacting the alcohol with phosphorous tribromide (PBr 3). 30 30
  • 31. This reaction proceeds via a two step mechanism. ‐ In the first step, the alcohol reacts with the phosphorous tribromide. The second step is an S N1 or S N2 substitution in which the bromide ion displaces the dibromophosphorous group. In a similar manner, alkyl iodides are prepared by reacting an alcohol with phosphorous triiodide. 31 31
  • 32. 32
  • 33. Ester formation § Esters are compounds that are commonly formed by the reaction of oxygen‐containing acids with alcohols. § The ester functional group is the § § Alcohols can be converted to esters by means of the Fischer Esterification Process. § In this method, an alcohol is reacted with a carboxylicacid in the presence of an inorganic acid catalyst. 33 33
  • 34. § Because the reaction is an equilibrium reaction, in order to receive a good yield, one of the products must be removed as it forms. § Doing this drives the equilibrium to the product side. § 34 34
  • 35. •The mechanism for this type of reaction takes place in seven steps: •1. The mechanism begins with the protonation of the acetic acid. • The π electrons of the carboxyl group, , migrate to pick up the positive charge. 35 35
  • 36. 3. The oxygen of the alcohol molecule attacks the carbocation. • • 4. The oxonium ion that forms loses a proton. • • 5. One of the hydroxyl groups is protonated to form an oxonium ion. • • • 36 36
  • 37. 6. An unshared pair of electrons on another hydroxy group re- establishes the carbonyl group, with the loss of a water molecule. • • 7. The oxonium ion loses a proton, which leads to the production of the ester. 37 37
  • 38. § Alkyl sulfonate formation. § Alcohols may be converted to alkyl sulfonates, which are sulfonic acid esters. § These esters are formed by reacting an alcohol with an appropriate sulfonic acid. § For example, methyl tosylate, a typical sulfonate, is formed by reacting methyl alcohol with tosyl chloride. 38 38
  • 39. • Other sulfonyl halides that form alkyl sulfonates include: • 39 39
  • 40. § These groups are much better leaving groups than the hydroxyl group because they are resonance stabilized. § Alcohol molecules that are going to be reacted by S N1 or S N2 mechanisms are often first converted to their sulfonate esters to improve both the rate and yield of the reactions. 40 40
  • 41. Formation of aldehydes and ketones. § The oxidation of alcohols can lead to the formation of aldehydes and ketones. § Aldehydes are formed from primary alcohols, while ketones are formed from secondary alcohols. § Because you can easily further oxidize aldehydes to carboxylic acids, you can only employ mild oxidizing agents and conditions in the formation of aldehydes. 41 41
  • 42. •Typical mild oxidizing agents include manganese dioxide (MnO2), Sarett‐Collins reagent (CrO3(C 5H 5N) 2), and pyridinium chlorochromate (PCC). • 42 42
  • 43. •Examples of the oxidation of primary alcohols: • 43 43
  • 44. vBecause ketones are more resistant to further oxidation than aldehydes, stronger oxidizing agents and higher temperatures may be employed. vSecondary alcohols are normally converted to ketones by reaction with potassium dichromate (K2Cr2O7), potassium permanganate (KMnO4), or chromium trioxide in acetic acid (CrO3/CH3COOH). 44 44
  • 45. •Examples of the oxidation of secondary alcohols • • 45 45
  • 46. Carboxylic acid formation. vUpon oxidation with strong oxidizing agents and high temperatures, primary alcohols completely oxidize to form carboxylic acids. vThe common oxidizing agents used for these conversions are concentrated potassium permanganate or concentrated potassium dichromate. 46 46
  • 47. •Examples of this type of oxidation: • 47 47
  • 48. The Alcohol Reaction Map vEther formation via substitution reactions vElimination of alcohols to form alkenes vConversion of alcohols to alkyl halides via substitution reactions vCleavage of ethers vOpening of epoxides vReactions of thiols • 48
  • 49. 49
  • 50. Uses of Alcohol In Daily Life, Medicines, Pharmacy 50
  • 51. Uses of Alcohol: •There are different types of alcohol with different uses. •The various types of alcohols and their uses range in applications from medicine to cooking. •During the coronavirus pandemic, sanitisers and masks rose to fame overnight. •Hand sanitizers contain 99.5% alcohol. • The alcohol present in sanitizers is isopropyl alcohol. 51
  • 53. 1. As a Chemical Feedstock • Methanol is widely used as a chemical feedstock in the production of methanal or formaldehyde by catalytic oxidation. • It is also used in the manufacture of acetic acid. • Formaldehyde or HCHOHCHO is used in the manufacture of plastics, paints, explosives, textiles and cosmetics. 2. As a Solvent • Methanol is used as a solvent for inks, adhesives, resins and dyes. • Methanol is often added to ethanol to discourage overconsumption of alcohol. • It is also used as a solvent in the pharmaceutical industry. • It is used in antifreeze for automotive radiators and screen-wash. • 53 Methanol (CH3OH)
  • 54. 3. As a Fuel • Methanol is used as an additive in petrol to improve combustion. • It can be used as a fuel in several internal combustion engines. • The equation for the combustion of methanol is given by- 2CH3OH+3O2→4H2O+2CO22CH3OH+3O2→4H2O+2CO2 Biodiesel • Biodiesel is produced by reacting vegetable oils with methanol. • The main product is a methyl ester of a long-chain fatty acid, which is used as biodiesel. • Glycerol is produced as a by-product in the reaction. • Biodiesel can be used as a replacement fuel in most modern diesel engines. 54
  • 55. Advantages: • Methanol can be stored easily compared to hydrogen gas or natural gas. • It is biodegradable and has a very short half-life in groundwater. • Methanol easily blends with gasoline/diesel and has the potential to substitute them altogether. • Methanol as fuel is cleaner than gasoline or LPG. Hence, methanol cook- stoves can help in achieving the objective of access to clean cooking fuels. Disadvantages: • Methanol tends to corrode aluminum and some other metals. • Its energy density is approximately half of the energy density offered by gasoline. 55
  • 57. 1. As an Ingredient in Alcoholic Beverages • Ethanol (or ethyl alcohol) is the type of alcohol that over two billion people drink every day. • This type of alcohol is produced by the fermentation of yeast, sugars, and starch. • The human liver can metabolise ethanol, but only in limited quantities. • There are two categories of alcoholic beverages: a. Distilled alcohol: • Distillation converts a fermented substance into another substance with an even higher concentration of alcohol. • It concentrates alcohol by separating it from the water and other components of a fermented substance. • Liquors and spirits are distilled alcoholic beverages. • They contain more alcohol by volume than undistilled drinks. • In general, a distilled alcoholic beverage will have a higher alcohol proof. 57
  • 58. b. Un-distilled alcohol: • Un-distilled alcohols are also called fermented drinks. • Fermentation is the process by which bacteria or yeast chemically converts sugar into ethanol. • Wine and beer are both fermented, un-distilled alcoholic beverages. • Wineries ferment grapes to make wine, and breweries ferment barley, wheat, and other grains to make beer. 58
  • 59. 2. To Produce Methylated Spirit (meth) • To discourage the over-consumption of alcohol, ethanol is often mixed with methanol. • This process is known as Denaturing of ethanol. • The resulting mixture is also called methylated spirit, which is poisonous, making ethanol unfit for consumption. • Methylated spirit is combustible; hence it can be used in lamps and stoves made for camping. • Methylated spirit is used to remove ink from various kinds of surfaces, such as metals and plastics. • Methylated spirit is used as a component of household cleaning products, usually glass cleaners. • 59
  • 60. 3. As a Solvent • Ethanol is used as a solvent to dissolve many organic compounds that are insoluble in water. • It is used in perfumes, cosmetics, paints, detergents and inks. • Ethanol has antibacterial properties as it slows or stops the growth of micro-organisms (germs). • It alters the shapes of proteins in the micro-organisms preventing them from functioning effectively. • The denaturation of proteins happens when the bonds that hold the protein together to maintain its specific shape are broken. • For this reason, ethanol is used in hand sanitisers and hand wipes. 60
  • 61. •Ethanol (in concentrations ranging from 1% to 25%) is used as a solvent for some analgesics and mouthwashes. •Since it has a melting point of –114.1oC, ethanol is used as an ingredient in cooling baths in several laboratories. •It also serves as the active fluid in many spirit thermometers. • 61
  • 62. 4. Used as a Fuel • Ethanol acts as a clean fuel because it undergoes complete combustion. It burns with a clean, smokeless flame to produce carbon dioxide and water. • 2C2H5OH+6O2→6H2O+4CO22C2H5OH+6O2→6H2O+4CO2 • Ethanol is usually mixed with gasoline to produce ‘gasohol”, which is about 10% ethanol. • Using ethanol as a fuel reduces our dependency on natural fossil fuels such as petrol. In countries like Brazil with limited natural oil supplies, sugar cane is grown on a large scale. Fermentation of sugar cane is carried out to produce ethanol. The ethanol produced by fermentation is used as an alternative source of fuel. 62
  • 63. • Using ethanol as a fuel reduces our dependency on natural fossil fuels such as petrol. • In countries like Brazil with limited natural oil supplies, sugar cane is grown on a large scale. • Fermentation of sugar cane is carried out to produce ethanol. • The ethanol produced by fermentation is used as an alternative source of fuel. • Ethanol combustion produces carbon dioxide that returns to the atmosphere and is used by the green plants to produce glucose necessary for ethanol fermentation. • 63
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  • 65. Disadvantages of Bioethanol •The demand for biofuel crops means greater demand on rainforest land. •This leads to clearing rainforests into agricultural land, which may not consume carbon dioxide as efficiently as rainforests do. •The conditions required for growing biofuel crops may not be adequate in many parts of the world. •This discrepancy would not satisfy the demand for fuel. 65
  • 66. Disadvantages of Bioethanol cont’d •Modern petrol engines cannot use biofuels. Therefore, modification in petrol engines would lead to additional manufacturing costs. •Although biofuels are theoretically carbon-neutral, this does not account for the carbon dioxide emissions associated with growing, harvesting and transporting the crops or producing ethanol. •Therefore, overall, more carbon dioxide is emitted than is absorbed, which means that it contributes to global warming. •Using food crops to produce fuels, could cause food shortages or increases in food prices. • 66
  • 67. Propanol (CH3CH2CH2OH) •Propanol is short-chain alcohol with three C atoms. •11-propanol (nn-propyl alcohol, 11-propyl alcohol, or nn-propanol ) has a linear structure, whereas 22- propanol or isopropanol are branched. •Due to their properties (high volatility, rapid effect, and low toxicity), both 11-propanol and 22-propanol are often used in hand disinfectants because of their have excellent bactericidal activity. • 67
  • 68. 1. As a Solvent / Intermediate • Propanol is used as a solvent to produce other solvents such as antifreeze, lacquer formulations, soaps, dye solutions, window cleaner and more. • Propanol like isopropanol or isopropyl alcohol is most commonly used in the printing industry, especially flexographic ink. • It is used as a cleansing agent in floor polishes and metal degreasers. • Propanol acts as a chemical intermediate in the process of creating halides, propyl amines and propyl acetate. 68
  • 69. 2. Medical Use • Propanol exhibits antibacterial properties. • Rubbing alcohol and sanitisers contain isopropyl alcohol. • It is also used as a depressant or pain reliever. • It is found in alcoholic beverages as a by-product of fermentation. 3. Cosmetics • Propanol is used in different cosmetics, e.g. acetate is used as a remover for acrylic nails and fingernail polish. It is also used in perfumes. 4. As a Fuel • Propanol has a high octane number and is quite suitable for engine fuel usage. However, its manufacturing process is not economical. 69
  • 70. Butanol (CH3CH2CH2CH2OH) • nn-butanol, also known as 11-butanol, or butyl alcohol, is four-carbon linear chain alcohol. • It is produced by petrochemical processes or fermentation of sugars derived from corn. 1. In the Manufacturing Industry • Butanol is primarily used to manufacture plastics, polymers, lubricants, brake fluids, and synthetic rubber. • Butanol is an environment friendly and powerful solvent for cleaning and polishing products.| • Butanol can also be used as a fuel. • nn-Butanol is present in numerous beverages and food, and it is used as an artificial food flavouring agent. 70
  • 71. 2. In Cosmetic and Laboratory Industry • Butanol is used as a humectant for cellulose nitrate • It is used as a chemical feedstock for butyl ethanoate, a synthetic food flavouring agent in the food and confectionary industry. • They are used in the cosmetic industry in products such as shampoo, shaving products and soaps. • It is used as a chemical intermediate to create other vital compounds such as Glycol Ether, Acrylate Esters, Amino Resins, Acetates, and Amines. 3. As a Source of Fuel • nn-butanol has a higher energy content than ethanol. • It is more compatible with the gasoline structure and does not absorb water from ambient air. • Biobutanol can be used as a transportation fuel. Uses of Alcohols in Pharmacy • Doctors, nurses and medical practitioners disinfect their hands in alcoholic solutions before handling patients. • During surgery, the surgical area is cleaned with alcohol to stem infections. 71
  • 72. How is alcohol used in life-saving situations in the medical field. 72
  • 73. 1. Wound Dresser • Earlier, alcohol was used as an antiseptic, poured over wounds, and antidote for snake bites. • In addition, patients were given a drink of whiskey before an operation. More recently, alcohol is used as a mild sedative. 2. Cough and Cold Remedy • Alcohols are a popular cough remedy commodity. • It is believed to clear minor colds and congestion and is found in most cough syrups. 3. Hand Disinfectant • It is the most common use of alcohol in recent times. • Alcohols exhibit antifungal, antibacterial properties. • It is used as a disinfectant where soap and water are not readily available. 73
  • 74. 4. As a Local Rubefacient • Alcohol is applied to the skin to dilate blood vessels. As a result, the skin area becomes tender and absorbent to medicinal ointment application. 5. Used as a Diluent • Alcohols act as a diluent for many drugs, especially in homoeopathy treatment. • A small number of drugs can be diluted in low quantities of alcohol. • In these low quantities, alcohol is harmless to the body and increases the drug’s volume. 6. Used as a Solvent • Alcoholic ethanol is an excellent solvent for many drugs as it increases the concentration of solid drug matter. • This can also be used for filtration, distillation, and removal of impurities from the drug. 7. Used as a Pain Reliever • Alcohol is used as a pain reliever to abate acute pain. For example, in cancer patients, alcohol is usually injected near the affected area to deaden the nerve endings. This leads to pain reduction. 8. As an Antiseptic • Alcohol is used to sterilise medical equipment like injections needles, surgical blades, forceps, etc. • Alcohol acts as an antiseptic to clean scratches and mild wounds. 9. As a Preservative • In the laboratory, plant and animal specimens are usually preserved in alcohol. • This is because the bactericidal properties of alcohol destroy microbes and other harmful bacteria. 74
  • 75. 10. Crystallisation and Extraction • Alcohol is employed for the extraction of active ingredients from plants and other specimens. • The extraction is done by steam distillation. Due to the low boiling point, alcohol quickly evaporates and then percolates through the solid material. • Alcohol is also used in the crystallisation of compounds which is an essential step in the purification process. 11. As a Cleaning Agent • Alcohol is used as a cleaning agent in hospitals and medical facilities, and cleaning laboratories to eliminate microbial contamination. 12. Laboratory Staining • While carrying out experiments on plant tissue and animal tissue, staining of the specimen is essential. This staining is done with alcohol that helps highlight the specimen under the microscope. 13. Solvent for Analysis • Chemistry analytical processes like Chromatography analysis use Ethanol, Methanol, and Isopropanol as solvent. • Alcohol plays a vital role in the separation process using these analytical techniques. 14. Lighting Laboratories • Laboratories use ethanol lamps to light up. Ethanol burns cleanly and does not leave soot. 75
  • 76. Uses of Alcohol in Medicine and Pharmacology • Alcohol is an essential ingredient in medicines like cough syrups, respiratory treatment drugs. Pain relievers also contain a high percentage of alcohol. Here is a list of several drugs that have alcohol as an essential ingredient. 1. Amoxicillin Trihydrate • Amoxicillin is used to treat bacterial infection and endocarditis prevention. It treats anthrax prophylaxis, actinomycosis, and dental abscess. It contains alcohols, isopropanol, and propanediol as active ingredients. 2. Atazanavir Sulfate • Atazanavir contains isopropyl alcohol and propylene glycol, which is used in the treatment of HIV infections. 3. Bupropion Hydrochloride • Bupropion acts as a miscellaneous antidepressant used in the treatment of depressive disorders. 4. Phentermine Hydrochloride • Phentermine used in the treatment of obesity contains isopropyl alcohol, butyl alcohol, and propylene glycol. 5. Temazepam • Temazepam is used in the treatment of insomnia, and it contains isopropyl alcohol and butyl alcohol. 76
  • 77. 6. Tizanidine Hydrochloride • Tizanidine is a relaxant used in the treatment of muscle spasm. It contains isopropyl alcohol and butyl alcohol. 7. Zonisamide • Zonisamide is an inhibitor anticonvulsant that contains isopropyl alcohol and butyl alcohol. It is used in the treatment of seizures. • 8. Benadryl • Benadryl is an antihistamine used to relieve symptoms of allergy, hay fever, and the common cold. It contains alcohol, isopropyl alcohol, butyl alcohol. • 9. Codimal DM • Codimal is used to treat symptoms caused by the common cold, flu, allergies, or other breathing illnesses. It has isopropyl alcohol and butyl alcohol. • 10. Decaprin • It is a combination of drug-containing expectorants and nasal decongestants used to treat cough and nasal congestion. It contains isopropyl alcohol and butyl alcohol. 77
  • 78. 11. Vicks Cough 5.0% • Vicks cough contains alcohol used for the temporary treatment of cough, blocked nose, sinus pressure caused by infection or other breathing illnesses. 12. Anbesol Gel • Anbesol Gel contains benzocaine and is used as a local anaesthetic. It blocks nerve endings and numbs the skin and mouth surface. Anbesol Gel is made of almost 70% alcohol. 13. Dent’s Toothache Drops • Dent’s Toothache Drops are used to lessen toothache pain. It comprises almost 60% alcohol. 14. Dental Gel • Corsodyl Dental Gel is used to treat gum disease, control recurring mouth ulcers, prevent cavities and maintain mouth hygiene. It is made of 7.5% alcohol. 15. Toothache Drops • Tooth Drops have almost 20% alcohol and Benzocaine. • It is used for toothache, canker sores, sore gums, throat, mouth, and gum injury. • It is a local anaesthetic that works by numbing the painful place. 78
  • 79. Uses of Alcohols and Hydrocarbons •The major difference between an alcohol and a hydrocarbon is that alcohol has a hydroxyl functional group (–OH) bound to a saturated carbon atom and hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. •Hydrocarbons are the principal constituents of petroleum and natural gas. They serve as fuels and lubricants and are a precursor to the production of plastics, fibres, rubbers, solvents, explosives, and industrial chemicals. 79
  • 80. Uses of Alcohols and Hydrocarbons • Hydrocarbons are also found in plants, animals, and their fossils. • The familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. • Polymers are large molecules of hydrocarbons made up of repeating units, referred to as monomers. • They can be natural such as starch, or synthetic, like polyethylene, polyvinyl chloride (PVC), and polystyrene. • Most of these plastics are recycled and reprocessed into useful products. • For example, soft drink bottles are melted down and used for plastic furniture, carpets, or other applications. • 80
  • 81. Uses of Alcohol in the Human Body •Moderate alcohol use has possible health benefits, but it is not risk-free. The potential benefits of alcohol are relatively small and may not apply to all individuals. •Therefore, one should not begin drinking alcohol based on potential health benefits. •For many people, the possible benefits do not outweigh the risks and avoiding alcohol is the best course. 81
  • 82. What do you think are some risks associated with alcohol use? 82
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  • 90. Alcohol Poisoning •Occurs when drinking large quantities of alcohol within a short period of time •Binge drinking (≥5 drinks/drinking occasion) •Depresses nerves that control involuntary actions such as breathing and the gag reflex. 90
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  • 92. DON’T DRINK & DRIVE!!! DON’T DRINK & STUDY!!!! DRINK RESPONSIBLY!!!!!!