This document discusses sonochemistry, which is the application of ultrasound to chemical reactions and processes. It can be divided into three frequency regions: low frequency high power, high frequency medium power, and high frequency low power. The effects of sonic waves on chemical systems were first reported in 1927. Sonochemistry experienced growth in the 1980s with inexpensive generators. The origin of sonochemical effects is acoustic cavitation, where ultrasound induces vibrational motion in molecules that alternately compresses and stretches them, forming cavitation bubbles that collapse with extreme conditions like 2000-5000K temperature and 1800 atm pressure. Cavitational collapse can cause physical, chemical and biological effects through shear forces, jets and shock waves. Benefits of sonochemistry include decreased

1. DEPARTMENT OF CHEMISTRY
TKMM COLLEGE
NANGIARKULANGARA

2. SONOCHEMISTRY

3. SONOCHEMISTRY
 Application of ultrasound to chemical reactions and
processes
 Ultrasound is the part of sonic spectrum (20KHz-
10Mhz),can be divided into 3 regions
 Low frequency ,high power ultra sond (20-100KHz)
 High frequency ,medium power ultra sound (100KHz-
1MHz)
 High frequency ,low power ultra sound (1-10MHz)

4. SONOCHEMISTRY
 Understanding of the effect of sonic waves
and wave properties on chemical system
 The influence of sonic waves travelling
through liquids was first reported by
Robert William Wood and Alfred Lee
Loomis (1927)
 Sonochemistry experienced a renaissance
in 1980’s with the advent of inexpensive
and reliable generators of high intensity

5. THE ORIGIN OF SONOCHEMICAL EFFECTS

6. THE ORIGIN OF SONOCHEMICAL EFFECTS
 Origin of sonochemical effects in liquids ---Acoustic
cavitation
 Acoustic energy is mechanical energy ,is not
absorbed by molecules
 Ultrasound is transmitted through a medium via
pressure waves
 This induces vibrational motion of the molecules
 This alternately compress and stretch the molecular
structure of medium due to time –varying pressure
 The distance among the molecules vary as they

7.  If the intensity of ultrasound in a liquid is
increased ,a point is reached at which the
intramolecular forces are not able to hold the
molecular structure intact and it breaks down and
a cavity is formed
 This cavity is called cavitation bubble and this
process is called cavitation
 These bubbles finally collapse
 Cavitation is the formation,growth and implosive
collapse of bubble irradiated with sound is the

8. THEORIES ABOUT CAVITATION
 The hot- spot theory
 The electrical theory
 The plasma theory
 The most popular one is the hot-spot

9. SONOCHEMICAL EFFECTS
 Cavitational collapse creates drastic conditions inside the cavity
in the medium for an extremeley short time
 temperature 2000-5000K
 pressure upto 1800 atm
 A remarkable event durig cavitational collapse is the emission of
light under certain conditions - Sonoluminescence
 The cavitational collapse causes a couple of strong physical
effects outside the bubble - shear forces, jet and shock waves
 The cavitation induced effects can cause physical ,chemical and
biological effects
 Thus ultrasound found applications in chemistry, material and
life sciences and medicine

10. BENEFICIAL SONOCHEMICAL EFFECTS IN
CHEMIAL REACTIONS AND PROCESSES
 Decrease of reaction time and/or increase of
yield
 Possible switching of reaction pathway
 Use of less or avoidance of phase transfer
catalyst
 Activation of metals and solids

11. DEPARTMENT OF CHEMISTRY
TKMM COLLEGE
NANGIARKULANGARA