The document discusses various types of oxidative reactions and oxidizing agents used in liquid phase oxidation. It describes oxidation of several organic compounds like aniline and furfural using oxidizing agents such as hydrogen peroxide, sodium hypochlorite, oxygen gas, and ozone. Details about the structures and production methods of these oxidizing agents are provided. Common applications and reactions of the oxidizing agents are also summarized.

1. PRESENTED BY:
ANAM ILYAS
M.PHARM 1st YEAR
PHARMACEUTICAL CHEMISTRY
SPER(JAMIA HAMDARD)

2. ❑Introduction
❑Types of oxidative reactions
❑Liquid phase oxidation with oxidizing agents
❑Non-metallic Oxidizing agents such as:
1. Hydrogen peroxide
2. sodium hypochlorite
3. Oxygen gas
4. ozonolysis
2

3. ▪ Oxidation is a process of addition of oxygen and removal of hydrogen or loss of
an electron during a reaction by a molecule, atom or ion.
▪ Oxidation occurs when the oxidation state of a molecule, atom or ion is increased.
▪ The opposite process is called reduction, reduction is a process of removal of
oxygen and addition of hydrogen.
▪ Reduction occurs when there is a gain of electrons or the oxidation state of an
atom, molecule, or ion decreases.
▪ Oxidation and reduction always occur in pair, Therefore whenever something
is oxidised,something is reduced.
▪ Oxidation and reduction together are called "REDOX REACTION"
3

4. ▪ In the organic chemical industry, oxidation constitutes one of the most powerful
tools used in the synthesis of chemical compounds.
▪ The principle types of oxidative reactions may be as follows:
❑DEHYROGENATION:
It is illustrated in the transformation of:
➢ a primary alcohol to an aldehyde:
C2H5OH+ 1/2O2 CH3CHO + H2O
➢ Or a secondary alcohol to ketone:
CH3CHOH+ 1/2O2 CH3COCH3+ H2O
4

5. ❑ An atom of oxygen may be introduced into a molecule
➢ The oxidation of an aldehyde to an acid:
CH3CHO + ½ O2 CH3COOH
➢ Or of a hydrocarbon to an alcohol:
(C6H5)3CH + 1/2O2 (C6H5)3COH
❑ A combination of dehydrogenation and introduction of oxygen may occur, as in the
preparation of Aldehyde from hydrocarbon:
CH4 + O2 CH2O + H2O
➢ or the preparation of benzoic acid from benzyl alcohol:
C6H5CH2CH.OH + O2 C6H5COOH+ H2O 5

6. ❑ Dehydrogenation, oxygen introduction and destruction of carbon linkages may all occur in the
same process of oxidation.
➢ In the oxidation of naphthalene to phthalic anhydride:
C10H8 + 4.5O2 C8H4O3 + 2H2O + 2CO2
❑ Oxidation may be accomplished indirectly through the use of intermediate reaction.
C6H5.CH3 C6H5CCl3 C6H5COOH
C6H6 CH5SO3H C6H5OH
6
NaoH

7. ❑ Olefin may be oxidized under mild conditions to hydroxyl derivatives and may be converted to
aldehydes and carboxylic acids of lower molecular weight when stronger oxidizers are employed
thus, oleic acid can be converted to dihydroxystearic acid with Alkaline potassium permanganate.
CH3(CH2)7CH=CH(CH2)7COOH CH3(CH2)7CHOH(CH2)7-COOH
❑PEROXIDATION:occurs readily under certain condition. Thus some reaction occur directly with
air when catalyzed by uv radiation.
Isopropyl Radiation Isopropyl Benzene Peroxide
❑Amino compounds may be oxidized to azobenzene, p-aminophenol,or nitrobenzene under
moderate conditions or the N-containingradical may be completely removed under drastic
conditions.
➢In this way quinone is derived from Aniline.
KMnO4
Air/UV
7

8. ❑SULFUR COMPOUNDS:
▪ It may be oxidized by Acid permangnate, as in the preparation of sulfonate, trianals and tetranals
from (CH3)2C(S.C2H5)2
▪ In which the sulphide sulphur is oxidized to sulfonic groups.
▪ It should be noted that mercaptans behave differently towards oxidizing agents from the alcohol
in that the action of strong oxidizing agents increases the valence of the sulfur atom instead of
removing hydrogen as in case of alcohols. Thus,
Oxidation ,
CH3CH2OH CH3CHO + H2O
CH3CH2SH CH3CH2SO2OH
8

9. ▪ Liquid-phase oxidation is discussed in terms of the free radical chain mechanism
proposed by BOLLAND and his co-workers.
▪ It is a process in which air or oxygen gas is contacted with the liquid reagent.
▪ In Liquid phase oxidation H2O2 is being used more frequently as an oxidizing agent
in place of traditional oxygen transfer agents.
▪ This scheme was devised for certain oxidations in which hydroperoxide is the
major product.
9

10. ANILINE
Oxidizing agent product
Manganese dioxide in sulfuric acid Quinone
Potassium dichromate in dil. H2SO4 at
0-10oC,for 24 hour
Quinone
Potassium permangnate:
Acid
Alkaline
Neutral
Aniline black
Azobenzene + ammonia
Azobenzene + nitrobenzene
Alkaline hypochlorite Nitrobenzene
Hypochlorous acid P-aminophenol
10

11. FURFURAL
OXIDIZING AGENT PRODUCT
Sodium chlorate in neutral solution withV2O
catalyst
Fumaric acid
Sodium chlorate in dil. Acid with osmiumm
tetraoxide(OsO4), catalyst
Mesotarttaric acid
Hydrogen peroxide in presence of ferrous
salts
5-Hydroxyfurfural
Bromine water at 100oC Mucobromic acid
11

12. ▪ Non-metals act as oxidizing agent
because they tend to accept electrons
i.e. reduction.
▪ The substance which itself gets reduced
by causing oxidation of others is an
oxidizing agent.
▪ e.g., nonmetals.
12

13. ▪ Hydrogen peroxide H2O2 Pure form, it is a pale blue, clear liquid,slightly more
viscous than water.
▪ It is the simplest peroxide (a compound with an oxygen–oxygen single bond).
▪ It is used as an oxidizer, bleaching agent and antiseptic.
▪ Concentrated hydrogen peroxide, or "high-test peroxide", is a reactive oxygen
species and has been used as a propellant in rocketry. Its chemistry is dominated
by the nature of its unstable peroxide bond.
▪ It is unstable and slowly decomposes in the presence of light. Because of its
instability, It is typically stored with a stabilizer in a weakly acidic solution.
▪ It is found in biological systems including the human body.
▪ Enzymes that decompose hydrogen peroxide are classified as peroxidases.
13

14. ▪ Hydrogen peroxide (H2O2) is a
nonplanar molecule as shown by
Paul-Antoine Giguère in 1950 using
infrared spectroscopy, with (twisted)
C2 symmetry. Although the O−O
bond is a single bond
▪ The molecular structures of gaseous
and crystalline H2O2 are significantly
different.This difference is attributed
to the effects of hydrogen bonding,
which is absent in the gaseous state.
14

15. ▪ Previously, hydrogen peroxide was prepared
industrially by hydrolysis of ammonium persulfate,
which was itself obtained by the electrolysis of a
solution of ammonium bisulfate (NH4HSO4) in
sulfuric acid.
▪ Today, hydrogen peroxide is manufactured almost
exclusively by the anthraquinone process, which
was formalized in 1936 and patented in 1939.
▪ It begins with the reduction of an anthraquinone
(such as 2-ethylanthraquinone or the 2-amyl
derivative) to the corresponding anthra
hydroquinone, typically by hydrogenation on a
palladium catalyst. In the presence of oxygen.
▪ the anthrahydroquinone then undergoes
autoxidation: the labile hydrogen atoms of the
hydroxy groups transfer to the oxygen molecule,
to give hydrogen peroxide and regenerating the
anthraquinone. 15

16. ▪ Most commercial processes achieve oxidation by bubbling compressed air through a
solution of the anthrahydroquinone, with the hydrogen peroxide then extracted from the
solution and the anthraquinone recycled back for successive cycles of hydrogenation
and oxidation.
▪ The simplified overall equation for the process is:
H2 + O2 H2O2
▪ The economics of the process depend heavily on effective recycling of the extraction
solvents, the hydrogenation catalyst and the expensive quinone.
▪ A process to produce hydrogen peroxide directly from the elements has been of
interest for many years. Direct synthesis is difficult to achieve, as the reaction of
hydrogen with oxygen thermodynamically favours production of water.
▪ Systems for direct synthesis have been developed, most of which are based around
finely dispersed metal catalysts similar to those used for hydrogenation of organic
substrates.None of these has yet reached a point where they can be used for industrial-
scale synthesis.
16

17. ▪ Hydrogen peroxide is thermodynamically unstable and decomposes to form water
and oxygen.
H2O2 H2 + O2
▪ The rate of decomposition increases with rise in temperature, concentration and
pH, with cool, dilute, acidic solutions showing the best stability.
17

18. ▪ Hydrogen peroxide is frequently used as an oxidizing agent.
Example is oxidation of thioethers to sulfoxides
Ph-S-CH3 + H2O2 Ph-S(O)-CH3 + H2O
▪ Hydrogen peroxide is a weak acid, forming hydroperoxide or peroxide salts with
many metals.
▪ It also converts metal oxides into the corresponding peroxides.
For example: upon treatment with hydrogen peroxide, chromic acid forms an unstable
blue peroxide CrO(O2)2.
▪ This kind of reaction is used industrially to produce peroxoanions. For example,
reaction with borax leads to sodium perborate, a bleach used in detergent industry.
18

19. ▪ Sodium hypochlorite is a chemical compound with the formula NaOCl or NaClO,
comprising a sodium cation (Na+) and a hypochlorite anion(OCl−or ClO−).
▪ It may also be viewed as the sodium salt of hypochlorous acid.
▪ The anhydrous compound is unstable and may decompose explosively.
▪ It can be crystallized as a pentahydrate
▪ NaOCl·5H2O,a pale greenish-yellow solid which is not explosive and is stable if
kept refrigerated.
▪ Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute
solution commonly known as liquid bleach or simply bleach, a household chemical
widely used (since the 18th century) as a disinfectant or a bleaching agent.
19

20. ▪ The compound in solution is unstable and easily decomposes, liberating
chlorine, which is the active principle of such products. Indeed, sodium
hypochlorite is the oldest and still most important chlorine-based bleach.
▪ While sodium hypochlorite is non-toxic, its corrosive properties, common
availability, and reaction products make it a significant risk.
▪ In particular, mixing liquid bleach with other cleaning products, such as
acids or ammonia, may produce toxic fumes.
20

21. ▪ Oxidation of starch by sodium hypochlorite, that adds carbonyl and carboxyl
groups, is relevant to the production of modified starch products.
▪ In the presence of a phase-transfer catalyst, alcohols are oxidized to the
corresponding carbonyl compound (aldehyde or ketone).
▪ Sodium hypochlorite can also oxidize organic sulfides to sulfoxides or sulfones,
disulfides or thiols to sulfonylchlorides or bromides, imines to oxaziridines.
▪ It can also de-aromatize phenols.
21

22. ▪ Oxidation of metals and complexes Heterogeneous reactions of sodium
hypochlorite and metals such as zinc proceed slowly to give the metal oxide or
hydroxide.
NaClO + Zn ZnO + NaCl
▪ Homogeneous reactions with metal coordination complexes proceed somewhat
faster. This has been exploited in the Jacobsen epoxidation.
22

23. ▪ If not properly stored in airtight containers, sodium hypochlorite reacts with
carbon dioxide to form sodium carbonate
2 NaOCl (aq) + CO2 (g) Na2CO3 (aq) + Cl2 (g)
▪ Sodium hypochlorite reacts with most nitrogen compounds to form volatile
chloramines, dichloramines, and nitrogen trichloride
NH3 + NaClO NH2Cl + NaOH
NH2Cl + NaClO NHCl2 + NaOH
NHCl2 + NaClO NCl3 + NaOH 23

24. ❑ CHLORINATION OF SODA : Potassium hypochlorite was first produced in 1789 by Claude Louis
Berthollet by passing chlorine gas through a solution of potash lye.The resulting liquid,known as "Eau
de Javel" ("Javel water"),was a weak solution of potassium hypochlorite.Antoine Labarraque replaced
potash lye by the cheaper soda lye,thus obtaining sodium hypochlorite.
Cl2 (g) + 2 NaOH (aq) NaCl (aq) + NaClO (aq) + H2O (aq)
❑ ELECTROLYSIS OF BRINE: Near the end of the nineteenth century,E. S. Smith patented the chloralkali
process:a method of producing sodium hypochlorite involving the electrolysis of brine to produce
sodium hydroxide and chlorine gas,which then mixed to form sodium hypochlorite.The key reactions
are:
2 Cl_ Cl2 + 2 e− (at the anode)
2 H2O + 2 e− H2 + 2 HO− (at the cathode)
❑ FROM OZONE AND SALT : Sodium hypochlorite can be easily produced for research purposes by
reacting ozone with salt.
NaCl + O3 NaClO + O2
This reaction happens at room temperature and can be helpful for oxidizing alcohols. 24

25. ▪ Oxygen is the chemical element with the symbol O and atomic number 8.
▪ It is a member of the chalcogen group on the periodic table, a highly reactive
nonmetal, and an oxidizing agent that readily forms oxides with most elements as
well as with other compounds.
▪ By mass, oxygen is the third-most abundant element in the universe, after hydrogen
and helium.
▪ At standard temperature and pressure, two atoms of the element bind to form
dioxygen, a colourless and odourless diatomic gas with the formula O2.
▪ Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. As compounds
including oxides, the element makes up almost half of the Earth's crust.
25

26. ▪ Dioxygen is used in cellular respiration and many major classes of organic
molecules in living organisms contain oxygen, such as proteins, nucleic acids,
carbohydrates, and fats, as do the major constituent inorganic compounds of
animal shells, teeth, and bone.
▪ Most of the mass of living organisms is oxygen as a component of water, the major
constituent of lifeforms.
▪ Oxygen is continuously replenished in Earth's atmosphere by photosynthesis,
which uses the energy of sunlight to produce oxygen from water and carbon
dioxide.
▪ Oxygen is too chemically reactive to remain a free element in air without being
continuously replenished by the photosynthetic action of living organisms.
26

27. ▪ One hundred million tonnes of O2 are extracted from air for industrial uses
annually by two primary methods.
▪ The most common method is fractional distillation of liquefied air, with N2 distilling
as a vapor while O2 is left as a liquid.
▪ The other primary method of producing O2 is passing a stream of clean, dry air
through one bed of a pair of identical zeolite molecular sieves, which absorbs the
nitrogen and delivers a gas stream that is 90% to 93% O2.
▪ Oxygen gas can also be produced through electrolysis of water into molecular
oxygen and hydrogen.
27

28. ▪ Smelting of iron ore into steel consumes 55% of commercially produced
oxygen.[In this process, O2 is injected through a high-pressure lance into molten
iron, which removes sulphur impurities and excess carbon as the respective
oxides, SO2 and CO2.The reactions are exothermic, so the temperature increases to
1,700°C.
▪ Another 25% of commercially produced oxygen is used by the chemical industry.
Ethylene is reacted with O2 to create ethylene oxide, which, in turn, is converted
into ethylene glycol.
▪ Most of the remaining 20% of commercially produced oxygen is used in medical
applications, metal cutting and welding, as an oxidizer in rocket fuel, and in water
treatment.
28

29. ▪ Ozonolysis is a widely used reaction in organic synthesis. The reaction was
invented by Christian Friedrich Schoenbein in 1840.
▪ Alkenes and alkynes are the most common substrates for the ozonolysis reaction.
▪ Ozonolysis was an important diagnostic tool for the determination of the position of
unsaturation in unknown molecules before the invention and development of
spectroscopic techniques for identification and characterization of organic
molecules.
▪ The reaction was used for structure elucidation work because it provided chemists
with smaller and more readily identifiable carbonyl compounds.
29

30. ▪ The ozonolysis reaction involves bubbling ozone into a solution of olefin in an
organic solvent.
▪ The reaction is rapid and produces an intermediate called ozonide.
▪ The ozonide is unstable, and hence not isolated, but can be further reacted with
various reagents to give aldehydes, ketones, carboxylic acids, alcohols etc.
▪ When the ozonide is treated with mild reducing agents like phosphines and thio
compounds (typically dimethyl sulfide or thiourea is used) aldehydes and ketones
are produced.
▪ Ozonides can be treated with strong reducing agents like sodium borohydride to
produce alcohols.
▪ Ozonides when treated with oxidizing agents such as oxygen or hydrogen
peroxide, they produce carboxylic acids as the products.
30

31. ▪ Alkynes also undergo ozonolysis but very slowly compared to alkenes.
▪ Unlike alkenes, ozonides from alkynes do not need either an oxidizing agent or
reducing agent to provide end products.
▪ Ozonides from alkynes upon treatment with water provide carboxylic acids are
products.
▪ Internal alkynes produce two different carboxylic acids while terminal alkynes
produce carboxylic acid with one less carbon; the terminal carbon is converted to
carbon dioxide.
31

32. ▪ Alkanes get oxidized when treated with ozone. The products formed are alcohols,
aldehydes/ketones or carboxylic acids.The rate of oxidative cleavage of alkanes is
highest for tertiary C-H bond, followed secondary and primary.
OZONOLYSIS OF ELASTOMERS
▪ Ozone cracking is a form of stress corrosion cracking where active chemical
species attack products of a susceptible material. Ozone cracking was once
commonly seen in the sidewalls of tires but is now rare owing to the use of
antiozonants. Other means of prevention include replacing susceptible rubbers
with resistant elastomers such as polychloroprene.
32

33. ▪ https://www.sciencedirect.com/science/article/pii/S0009250954800029
▪ https://www.thoughtco.com/definition-of-oxidation-in-chemistry-605456
▪ https://www.slideshare.net/ShikhaPopali1/oxidation-pharmaceutical-process-
chemistry
▪ https://www.slideshare.net/mounikaperli/oxidizing-agentsampozonolysis
33

34. 34