Ultrasound

PRINCIPLES OF GREEN
CHEMISTRY
“Ultrasound assisted reaction”
PRESENTED BY
Mr. Suraj J. Patil.
B Pharm
UNDER THE GUIDANCE
Prof Dr. S. K. Mohite.(Sir)
M Pharm. PhD
Rajarambapu College of Pharmacy, Kasegaon
Tal- Walwa, Dist- Sangli.

CONTENTS
• Abstract
• Introduction
• Types of Sonochemical reaction
• Application
• Conclusion
• References

ABSTRCT
Ultrasound irradiation differs from conventional
energy sources (such as heat, light, or ionizing radiation) in
time, pressure , and energy per molecule. The use of
ultrasound waves in organic synthesis has attracted an
increasing interest over the last years. Use of ultrasound
waves as alternative source of energy is of great interest in
the area of green and pharmaceutical chemistry. This
review will focus on the uses of ultrasound waves in
heterocyclic chemistry, condensation reactions, substitution
reactions, oxidation, reduction, addition reactions,
photochemical reactions, protection/de protection
reactions, coupling reaction photochemical reactions,
polymerization reactions etc.

Introduction
Energy sources of chemical reactions
Heat Electricity
Microwaves Pressure
Pressure

What is sonochemistry
Sonochemistry is term used describe the effects
of ultrasound on chemical reaction. The name is derived
from the prefix “SONO” indicating sound paralleling the
longer established various techniques as above.
Sonochemistry is branch of chemistry dealing
with the chemical effects and application of ultrasonic
waves i.e. sound with frequencies above 20KHz (20,000
cycles per second )that lie beyond the upper limit of
human hearing although frequencies can be extended up
to 100MHz that’s especially affects on chemical reactivity .

Origin of sonochemical effects
Sound (ultrasound) is transmitted via waves
alternately compress and stretch the molecular structure of
the medium through which is process as shown below In
figure . Liquids irradiates with ultrasound can produce
bubbles . When under the proper condition these bubbles
undergo a violent collapse which generates very high
pressure and temperature .This process is called cavitation

Theory
Sonochemistry takes its origin in cavitation ,the reactivity
depends on characteristics of the bubble .The parameter
affecting the formation and stability of cavities are
1. Frequency
2. Solvent
3. Temperature
4. Bubbled gas

Types of Sonochemical reaction
Homogeneous liquid
phase reaction
Heterogeneous solid/liquid Heterogeneous liquid/liquid
phase reaction phase reaction

Homogenous liquid
1.In the bulk liquid immediately surrounding the bubble where the rapid
collapse of Bubble generates shear forces which can produce mechanical
effects .
2. In the bubble itself where any species introduced during its formation will be
Subjected to extreme condition of temperature and pressure on collapse
leading to Chemical effects .

Heterogeneous solid /liquid
Acoustic cavitation can produce dramatic effects on
solid in liquid imperfection Or trapped gas can act as the nuclei for
cavitation bubble formation on the surface collapse Can the lead to
shock waves break the particle apart .
cavitation bubble collapse in the liquid Phase near to a
particle can produce force into rapid motion

Heterogeneous liquid /liquid
In heterogeneous liquid /liquid reaction cavitation collapse at or
near the interface will Causes disruption and mixing resulting in the
formation of very fine emulsions.

Synthetic application -
The first report of ‘Sonochemical switching’ came from Ando et al
when suspension of benzyl bromide was treated with alumina
supported potassium cyanide in toluene under the stirring
condition the reaction provided diphenylmethane as product
formed via Friedal-crafts reaction, in contrast under sonic
condition benzyl cyanide was formed as the major product .

Conclusion
A diverse set of applications of ultrasound to enhancing
chemical reactivity has been explored, with important
applications in mixed phase synthesis materials chemistry, and
biomedical uses. Bubble collapse in liquids results in an
enormous concentration of energy from the conversion of the
kinetic energy of liquid motion into heating of the contents of
the bubble.

References
• Suslick, K.S. (1993) Ultrasound: Applications to Materials
Chemistry, in Encyclopedia of Materials Science and
Engineering; Cahn, R.W., ed.; Pergamon Press, Oxford;
3rd Suppl., pp. 2093-2098.
• http://www.shiga-med.ac.jp/chemistry/sonochemRes.html
• Luche, J. L., Synthetic Organic Sonochemistry, Plenum
Press, 2001
• Suslick, K. S., Ultrasound: Its Chemical, Physical, and
Biological Effects; VCH, 1988.
• Mason, T. J., Sonochemistry: Current Uses and Future
Prospect in Chemical and Industrial Processing, RSC,
1999

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