3. Chloroform-Properties
• Molecular Formula • CHCl3
• Molar Mass • 119.38 g/mol
• Appearance • Colourless liquid
• Density • 1.483 g/cc
• Melting Point • -63.5 oC
• Boiling Point • 61.2 oC
• Molecular shape • Tetrahedral
4. Chlorofom
• Chloroform (also known as trichloromethane and
methyl trichloride) is a chemical compound with
formula CHCl3.
• It is a colorless liquid with a pleasant, nonirritating
odor and a slightly sweet taste.
• It does not support combustion in air, although it will
burn when mixed with more flammable substances.
• It is a member of a subset of environmental pollutants
known as trihalomethanes, a by-product of
chlorination of drinking water and a long-standing
health concern.
5. Chloroform-history
Chloroform was first produced independently and
simultaneously in 1831 by Justus von Liebig and the French
chemist Eugene Soubeiran , who produced chloroform through
the action of chlorine bleach powder (calcium hypochlorite)
upon acetone (2-propanone) or ethanol (an application of the
generic process known as the haloform reaction).
• In 1847, the Edinburgh obstetrician, James Young Simpson first
used chloroform to effect general anesthesia during childbirth.
• The use of chloroform during surgery expanded rapidly
thereafter, especially in Europe.
6. Chloroform-Production
• Industrially, chloroform is produced by heating a mixture of chlorine
and either chloromethane or methane to 400-500°C.
• At this temperature, a series of chemical reactions occur, converting
the methane or chloromethane to progressively more chlorinated
compounds.
• CH4 + Cl2 → CH3Cl + HCl
• CH3Cl + Cl2 → CH2Cl2 + HCl
• CH2Cl2 +Cl2 → CHCl3 + HCl
• CHCl3 + Cl2 → CCl4 + HCl
• The output of this process is a mixture of the four chloromethanes,
chloromethane, dichloromethane, chloroform (trichloromethane), and
tetrachloromethane, which are then separated by distillation.
7. Chloroform-uses
• In the late 19th and early 20th centuries, chloroform was
used as an inhaled anesthetic during surgery. However,
safer, more flexible drugs have entirely replaced it in this
role. The major use of chloroform today is in the
production of the freon refrigerant R-22. However,, this
use can be expected to decline as R-22 is replaced by
refrigerants that are less liable to result in ozone
depletion.
• Smaller amounts of chloroform are used as a solvent in
the pharmaceutical industry, and for producing dyes and
pesticides.
• Chloroform is often used as a tool in kidnapping,
especially in books and movies.
• Chloroform containing deuterium (heavy hydrogen),
CDCl3, is the most common solvent used in Nuclear
Magnetic Resonance (NMR) spectroscopy.
8. Chloroform-safety
• As might be expected from its use as an anesthetic,
inhaling chloroform vapors depresses the central
nervous system. Breathing about 900 ppm for a short
time can cause dizziness, fatigue, and headache.
• Chloroform once appeared in toothpastes, cough syrups,
ointments, and other pharmaceuticals, but it has been
banned in consumer products.
11. Ethyl Alcohol
• Molecular Formula • C2H5OH
• Molar Mass • 46.07 g/cc
• Appearance • Colourless liquid
• Density • 0.789 g/cc
• Melting Point • -114.3 C
• Boiling Point • 78.4 C
12. Ethyl Alcohol
• Ethanol, also called ethyl alcohol, pure
alcohol, grain alcohol, or drinking
alcohol, is a volatile, flammable, colorless
liquid.
• It is a powerful psychoactive drug and one
of the oldest recreational drugs.
• It is best known as the type of alcohol
found in alcoholic beverages.
• In common usage, it is often referred to
simply as alcohol or spirits.
13. Ethyl alcohol
• Ethanol is a straight-chain alcohol, and its molecular
formula is C2H5OH.
• Its empirical formula is C2H6O.
• An alternative notation is CH3–CH2–OH, which indicates
that the carbon of a methyl group (CH3–) is attached to
the carbon of a methylene group (–CH2–), which is
attached to the oxygen of a hydroxyl group (–OH).
• It is a constitutional isomer of dimethyl ether.
• Ethanol is often abbreviated as EtOH, using the common
organic chemistry notation of representing the ethyl
group (C2H5) with Et.
14. Ethyl Alcohol
• The fermentation of sugar into ethanol is one of the
earliest organic reactions employed by humanity.
• The intoxicating effects of ethanol consumption have
been known since ancient times.
• In modern times, ethanol intended for industrial use is
also produced from by-products of petroleum refining.
• Ethanol has widespread use as a solvent of substances
intended for human contact or consumption, including
scents, flavorings, colorings, and medicines.
• In chemistry, it is both an essential solvent and a
feedstock for the synthesis of other products.
• It has a long history as a fuel for heat and light, and more
recently as a fuel for internal combustion engines.
15. Ethyl Alcohol
• Ethanol is a volatile, colorless liquid that has
a strong characteristic odor. It burns with a
smokeless blue flame that is not always visible
in normal light.
Ethanol is a versatile solvent, miscible with water
and with many organic solvents, including
acetic acid, acetone, benzene, carbon tetrachloride,
chloroform, diethyl ether, ethylene glycol, glycerol, nitromethane,
pyridine, and toluene.
It is also miscible with light aliphatic hydrocarbons, such as pentane
and hexane, and with aliphatic chlorides such as trichloroethane
and tetrachloroethylene.
16. Ethyl alcohol-production
• Ethanol is produced both as a petrochemical, through the hydration
of ethylene, and biologically, by fermenting sugars with yeast. Which
process is more economical is dependent upon the prevailing prices
of petroleum and of grain feed stocks.
• Ethylene hydration
• Ethanol for use as an industrial feedstock or solvent is often made
from petrochemical feed stocks, primarily by the acid-catalyzed
hydration of ethylene, represented by the chemical equation
– C2H4(g) + H2O(g) → CH3CH2OH(l).
17. Ethyl alcohol-production
• Ethanol for use in alcoholic beverages, and the vast majority of
ethanol for use as fuel, is produced by fermentation. When certain
species of yeast metabolize sugar they produce ethanol and carbon
dioxide. The chemical equation below summarizes the conversion:
• C6H12O6 → 2 CH3CH2OH + 2 CO2.
• The process of culturing yeast under conditions to produce alcohol
is called fermentation. This process is carried out at around 35–40
°C.
• To produce ethanol from starchy materials such as cereal grains,
the starch must first be converted into sugars. In brewing beer, this
has traditionally been accomplished by allowing the grain to
germinate, or malt, which produces the enzyme amylase. When the
malted grain is mashed, the amylase converts the remaining
starches into sugars.
19. Grades of ethanol
• Denatured alcohol-
• Absolute Ethanol- Absolute or anhydrous alcohol refers to ethanol
with a low water content. Absolute ethanol is used as a solvent for
laboratory and industrial applications.
• Rectified spirits - Rectified spirit, an azeotropic composition
containing 4% water, is used instead of anhydrous ethanol for
various purposes.
20. Reactions of ethanol
• Ethanol is classified as a primary alcohol, meaning that the carbon
to which its hydroxyl group is attached has at least two hydrogen
atoms attached to it as well. Many of the reactions of ethanol occur
at its hydroxyl group.
• Ester formation: In the presence of acid catalysts, ethanol reacts
with carboxylic acids to produce ethyl esters and water:
RCOOH + HOCH2CH3 → RCOOCH2CH3 + H2O
• This reaction, which is conducted on large scale industrially,
requires the removal of the water from the reaction mixture as it is
formed.
• Dehydration: Strong acid desiccants cause the dehydration of
ethanol to form diethyl ether and other byproducts.
• 2 CH3CH2OH → CH3CH2OCH2CH3 + H2O (on 120 °C)
21. Reactions of ethanol
• Combustion: Complete combustion of ethanol forms carbon
dioxide and water
– C2H5OH + 3 O2 → 2 CO2 + 3 H2O(l);
– (ΔHc = −1371 kJ/mol) specific heat = 2.44 kJ/(kg·K)
• Acid-base chemistry
• Ethanol is a neutral molecule and the pH of a solution of ethanol in
water is nearly 7.00. Ethanol can be quantitatively converted to its
conjugate base, the ethoxide ion (CH3CH2O−), by reaction with an
alkali metal such as sodium:
– 2 CH3CH2OH + 2 Na → 2 CH3CH2ONa + H2
• or a very strong base such as sodium hydride
– CH3CH2OH + NaH → CH3CH2ONa + H2
• The acidity of water and ethanol are nearly the same, as indicated
by their pKa of 15.7 and 16 respectively. Thus, sodium ethoxide and
sodium hydroxide exist in an equilbrium that is closely balanced:
– CH3CH2OH + NaOH CH3CH2ONa + H2O
22. Reactions of ethanol
• Halogenation
• Ethanol reacts with hydrogen halides to produce
ethyl halides such as ethyl chloride and ethyl
bromide via an sn2 reaction:
– CH3CH2OH + HCl → CH3CH2Cl + H2O
• These reactions require a catalyst such as zinc
chloride. HBr requires refluxing with a sulfuric
acid catalyst.
• CH3CH2OH + SOCl2 → CH3CH2Cl + SO2 + HCl
• Upon treament with halogens in the presence of
base, ethanol gives the corresponding haloform
(CHX3, where X = Cl, Br, I).
25. Acetone-Properties
• Molecular Formula • C3H6O
• Molar Mass • 58.08 g/ mol
• Appearance • Colourless liquid
• Density • 0.7925 g/cc
• Melting Point • −94.9 °C,
• Boiling Point • 56.53 °C,
• Molecular shape • trigonal planar at C=O
26. Acetone
• Acetone is the organic compound with the
formula (CH3)2CO.
• This colorless, mobile, flammable liquid is
the simplest example of the ketones.
• Acetone is miscible with water and serves
as an important solvent in its own right,
typically as the solvent of choice for
cleaning purposes in the laboratory.
27. Acetone -Production
• Acetone is produced directly or indirectly
from propylene.
• Most commonly, in the cumene process,
benzene is alkylated with propene and the
resulting cumene (isopropylbenzene) is
oxidized to give phenol and acetone:
– C6H5CH(CH3)2 + O2 → C6H5OH + (CH3)2CO.
• Acetone is also produced by the direct
oxidation of propene with a Pd(II)/Cu(II)
catalyst, akin to the Wacker process.
28. Acetone uses
• About half of the world's production of acetone is
consumed as a precursor to methyl methacrylate.
• This application begins with the initial conversion of
acetone to its cyanohydrin:
– (CH3)2CO + HCN → (CH3)2C(OH)CN
• In a subsequent step, the nitrile is hydrolyzed to the
unsaturated amide, which is esterified:
– (CH3)2C(OH)CN + CH3OH → CH2=(CH3)CCO2CH3 + NH3
• The second major use of acetone entails its
condensation with phenol to give bisphenol A:
– (CH3)2CO + 2 C6H5OH → (CH3)2C(C6H4OH)2 + H2O
• Bisphenol-A is a component of many polymers such as
polycarbonates, polyurethanes, and epoxy resins.
29. Acetone-as solvent
• Acetone is a good solvent for most plastics and synthetic fibres
including those used in laboratory bottles made of polystyrene,
Polycarbonate and some types of polypropylene.
• It is ideal for thinning fiberglass resin, cleaning fiberglass tools and
dissolving two-part epoxies and superglue before hardening.
• It is used as a volatile component of some paints and varnishes.
• As a heavy-duty degreaser, it is useful in the preparation of metal
prior to painting; it also thins polyester resins, vinyl and adhesives.
• Many millions of kilograms of acetone are consumed in the
production of the solvents methyl isobutyl alcohol and methyl
isobutyl ketone. These products arise via an initial aldol
condensation to give diacetone alcohol.
2 (CH3)2CO → (CH3)2C(OH)CH2C(O)CH3
• Acetone is used as a solvent by the pharmaceutical industry and as
a denaturation agent in denatured alcohol.
• Acetone is also present as an excipient in some pharmaceutical
products.
31. Acetic anhydride-Properties
• Molecular Formula • C4H6O3
• Molar Mass • 102.09 g/mol
• Appearance • Clear liquid
• Density • 1.082 g/cm3
• Melting Point • -73. oC
• Boiling Point • 139.8 oC
32. Acetic anhydride
• Acetic anhydride, or ethanoic
anhydride, is the chemical compound
with the formula (CH3CO)2O.
• Commonly abbreviated Ac2O, it is the
simplest isolatable acid anhydride and is a
widely used reagent in organic synthesis.
• It is a colorless liquid that smells strongly
of acetic acid, formed by its reaction with
the moisture in the air.
33. Acetic anhydride-structure
• Acetic anhydride, like many other acid anhydrides that
are free to rotate, has experimentally been found to be
aplanar.
• The pi system linkage through the central oxygen offers
very weak resonance stabilisation compared to the
dipole-dipole repulsion between the two carbonyl
oxygens.
• Like most acid anhydrides, the carbonyl carbon of acetic
anhydride is a potent electrophile as the leaving group
for each carbonyl carbon (a carboxylate) is a good
electron-withdrawing leaving group.
34. Acetic anhydride
• Acetic anhydride is produced by carbonylation of methyl
acetate
– CH3CO2CH3 + CO → (CH3CO)2O
• This process involves the conversion of methyl acetate
to methyl iodide and an acetate salt. Carbonylation of the
methyl iodide in turn affords acetyl iodide, which reacts
with acetate salts or acetic acid to give the product.
Rhodium and lithium iodides are employed as catalysts.
Because acetic anhydride is not stable in water, the
conversion is conducted under anhydrous conditions. In
contrast, the Monsanto acetic acid process, which also
involves a rhodium catalyzed carbonylation of methyl
iodide, is at least partially aqueous.
35. • To a decreasing extent, acetic anhydride is also
prepared by the reaction of ketene with acetic acid at
45–55 °C and low pressure (0.05–0.2 bar).
• H2C=C=O + CH3COOH → (CH3CO)2O (ΔH = −63
kJ/mol)
• Ketene is generated by dehydrating acetic acid at 700–
750 °C in the presence of triethyl phosphate as a
catalyst or by the thermolysis of acetone at 600–700 °C
in the presence of carbon disulfide as a catalyst.
– CH3COOH H2C=C=O + H2O (ΔH = +147 kJ/mol)
– CH3COCH3 → H2C=C=O + CH4
• The route from acetic acid to acetic anhydride via ketene
was developed by Wacker Chemie in 1922.
36. Acetic anhydride reactions
• The reaction of acetic anhydride with ethanol yields ethyl
acetate:
(CH3CO)2O + CH3CH2OH → CH3CO2CH2CH3 +
CH3COOH
• Aromatic rings are acetylated in the presence of an acid
catalyst. Illustrative is the conversion of benzene to
acetophenone:
– (CH3CO)2O + C6H6 → CH3COC6H5 + CH3CO2H
• Ferrocene may be acetylated too
– Cp2Fe + (CH3CO)2O → CpFe(C5H4COCH3)
Hydrolysis
(CH3CO)2O + H2O → 2 CH3CO2H
37. Acetic anhydride Applications
• Ac2O is mainly used for acetylations leading to
commercially significant materials.
• Its largest application is for the conversion of
cellulose to cellulose acetate, which is a
component of photographic film and other
coated materials.
• Similarly it is used in the production of aspirin,
acetylsalicylic acid, which is prepared by the
acetylation of salicylic acid.
• In starch industry, acetic anhydride is a common
acetylation compound, used for the production of
modified starches
39. Formaldehyde-Properties
• Molecular Formula • CH2O
• Molar Mass • 30.026g/ mol
• Appearance • Colourless lgas
• Melting Point • −92.6 °C,
• Boiling Point • -21°C,
• Molecular shape • Trigonal planar
40. Formaldehyde
• Formaldehyde is an organic compound
with the formula CH2O.
• As the simplest aldehyde, it is an
important precursor to many other
chemical compounds, especially for
polymers.
• In view of its widespread use, toxicity and
volatility, exposure to formaldehyde is a
significant consideration for human health.
41. Formaldehyde-Production
• Formaldehyde is produced industrially by the catalytic
oxidation of methanol. The most common catalysts are
silver metal or a mixture of an iron and molybdenum or
vanadium oxides.
• In the more commonly used FORMOX process
methanol and oxygen react at ca. 250–400 °C in
presence of iron oxide in combination with molybdenum
and/or vanadium to produce formaldehyde according to
the chemical equation:
– 2 CH3OH + O2 → 2 CH2O + 2 H2O
• The silver-based catalyst usually operates at a higher
temperature, about 650 °C. Two chemical reactions on it
simultaneously produce formaldehyde: that shown above
and the dehydrogenation reaction:
– CH3OH → H2CO + H2