2. Electrosynthesis
by Class 11, Kendriya Vidyalaya 2, Kalpakkam
Done by
Krishnaprasad K.A.
D.J. Vineeth
L. Narayanan
Antriksh Rathore

3. What is Electrosynthesis?
• Electrosynthesis in organic chemistry is the synthesis of
chemical compounds in an electrochemical cell.
• The main advantage of electrosynthesis over an ordinary
redox reaction is avoidance of the potential wasteful
other half-reaction and the ability to precisely tune the
required potential.

4. Experimental Setup
• The basic setup:
1)A Galvanic cell
2)A Potentiostat and
3)Two electrodes.
Good electrosynthetic conditions use a solvent
and electrolyte combination that minimizes
electrical resistance.
• Electrodes are selected which provide favorable
electron transfer properties towards the substrate
while maximizing the activation energy for side
reactions.

5. Experimental Setup

6. Experimental Setup
• Two basic cell types: undivided cell & divided cell type
• In divided cells the cathode and anode chambers are separated with
a semiporous membrane.
• Divided cell permits the diffusion of ions while restricting the flow of
the products and reactants. This is important when unwanted side
reactions are possible.

7. REACTIONS INVOLVED
•Anodic Oxidations
•Cathodic Reductions

8. Anodic Oxidations
• The most well-known electrosynthesis is the Kolbe
electrolysis.
• A variation is called the non-Kolbe reaction when a
heteroatom (nitrogen or oxygen) is present at the αposition. The intermediate oxonium ion is trapped by a
nucleophile usually solvent.

9. Anodic Oxidations
• In the so-called Crum Brown–Walker reaction an aliphatic
dicarboxylic acid is oxidized forming the elongated di-acid.
• Amides can be oxidized through a N-acyliminium ion which can be
captured by a nucleophile.
This reaction type is called a Shono oxidation. An example is the αmethoxylation of N-carbomethoxypyrrolidine.

10. Cathodic Reductions
• In the Markó-Lam deoxygenation, an alcohol
could be almost instantaneously deoxygenated
by electroreducing their toluate ester.

11. Cathodic Reduction
• The cathodic hydroisomerization of
activated olefins is applied industrially in
the synthesis of adiponitrile from 2
equivalents of acrylonitrile:

12. Cathodic Reduction
• The Tafel rearrangement (Julius Tafel, 1907) at one time
was relevant to the synthesis of certain hydrocarbons
from alkylated ethyl acetoacetate, a reaction
accompanied by the rearrangement reaction of the alkyl
group:

13. APPLICATIONS OF
ELECTROSYNTHESIS

14. Research & Development
• Electrochemical expertise in electrosynthesis includes the following
fields:
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Electrosynthesis of inorganic and organic (including pharmaceuticals) compounds
Energy Storage
Batteries and fuel cells
Electrodialysis
Membrane separation processes including salt splitting
Sensors
Environmental electrotechnology: water purification; metal recovery; pollutant
destruction; recovery, recycle and reuse

15. Inorganic Compounds
Synthesis
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Electrochemical synthesis of inorganic compounds offers several
advantages over conventional synthesis and often provides the only viable
route.
Electrosynthetic processes can often be run under milder operating
conditions with fewer chemical reagents.
Examples:
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Chlor-alkali manufacture
Aluminum Refining
Water Electrolysis to produce hydrogen and oxygen
Manufacture of bromine, chlorate, perchlorate, ferrate, etc.
Metals extraction and refining: Al, Na, Mg, Li, etc.
Metal oxides manufacture

16. Organic Compound
Synthesis
• Industrial scale electrochemical processing of organic chemicals : In
practice for almost 100 years. An estimated 120 different processes
– piloted .
At least 60 are now commercial.
Other examples of reactions that can be carried out electrochemically
include:
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Nitro Reduction
Halogenation
Methoxylation
Acetoxylation
Hydrogenation
Carboxylation
Coupling Reactions
Acetamidation
Dehalogenation
Cyanation

18. Energy Storage
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This technology was based on a polysulfide/bromide system.
The Redox Flow Battery : Form of rechargeable battery in which electrolyte
flows through an electrochemical cell.
On charge, it converts electricity into chemical energy.
The electrolyte, and therefore energy, is stored externally in tanks until the
energy is required when the solution is pumped back into the
electrochemical cell discharging the chemical energy as electrical energy.

19. Advantages of E.S
Advantages:
• This is one of only a few technologies that can separate energy and
power requirements. Power is determined by the size of the
electrochemical cell whereas the energy is proportional to the size of
the storage tanks.
• Large amounts of energy (up to hundreds of MWh) can be stored
until required with little loss.
• High efficiency conversion from electrical to chemical energy
• Long cycle life with quick response times.

20. Applications of E.S
Applications:
• Large (1 kWh - many MWh) stationary applications.
• Load leveling: Store energy during times of low demand
and provide electricity during peak time.
• Storing energy from renewable sources such as wind or
solar to supply power during low generation periods.
• Uninterrupted power supply (UPS), to provide power
when main power fails.

22. Electro Dialysis
• Electrodialysis (ED) is a very versatile technology for the separation
of difficult mixtures.
• Electrodialysis is an electromembrane process in which ions are
transported through ion permeable membranes from one solution to
another under the influence of a potential gradient.
• The electrical charges on the ions allow them to be driven through
the membranes fabricated from ion exchange polymers.
• Types of Membranes used:
– Ion Permeable Membranes
– Bipolar membranes

23. Ion Permeable
Membrane
• The ion permeable membranes used in electrodialysis are essentially
sheets of ion-exchange resins.
• They usually also contain other polymers to improve mechanical
strength and flexibility.
• The resin component of a cation-exchange membrane would have
negatively charged groups (e.g., -SO3-) chemically attached to the
polymer chains.

24. Bipolar Membrane
• Bipolar membranes consist of an anion-permeable membrane and a
cation permeable membrane laminated together.
• When this composite structure is oriented such that the cationexchange layer faces the anode it is possibleto spit water into proton
and hydroxyl ions by imposing a potential field.
• Multiple bipolar membranes along with other ion permeable
membranes can be placed between a single pair of electrodes.

25. Salt Splitting
• Salt splitting is a relatively new technology dependent on
the availability of modern membranes.
• Its development has usually been driven by two major
factors,
– The first is the desire to produce caustic soda without the coproduction of chlorine.
– The second is the increased cost of disposing of heavily laden
salt solutions.

26. Sodium Sulphate for
Salt Splitting

27. Caustic Soda
production

28. Salt splitting with
Bipolar Membranes

29. No chlorine
produced.!

30. Salt Splitting
• With the demand for Chlorine predicted to fall down, the need for
using production of NaOH without Chlorine has to be done.
• Electrosynthesis of Sodium Sulphate can be done to give Caustic
Soda.
• A successful technology for treatment of sodium sulfate wastes will
likely require additional economic incentives such as the
coproduction of a saleable product (for example ammonium sulfate),
or credits for the elimination of a waste stream.
• Technologies for the production of commodity quantities of caustic
will need to rely on very low power costs and an increasing
imbalance in causticchlorine production.
• Modular on-site production of chemicals will facilitate the
implementation of electrochemical technologies.

31. Electrosynthesis Inc.
• Electrosynthesis Company, Inc. specializes in the development of
electrochemical technologies for energy storage systems, fuel cells,
electrodialysis, separations, sensors, synthesis of inorganic and
organic chemicals and recycling of waste streams.
• Achievements:
– New method for production of Potassium Ferrate by
electrosynthesis which has reduced its price from $100/g to $2/g.
– New methods for synthesising Caustic Soda without Chlorine as
a byproduct.
– Developing large scale energy storage systems using
electrosynthesis.