Chapter 7
Hybrid Technologies in Action:
Sonochemistry and Beyond
Abstract In the search for new forms of synergism, chemists have always looked
for novel combinations of tools and processes that may produce improvements in
efficiency and selectivity, principally, but also time frame, safety, costs and sustainability. Ultrasound has been combined with microwave heating either in loop or in
flow mode or simultaneously in batch. Relevant examples are reported on the use of
hybrid reactors under combined ultrasound and microwave irradiation.
7.1 Combined Microwaves/Ultrasound; A Brief
Introduction
The first evidence of the synergistic effect produced by simultaneous
microwave/ultrasound (MW/US) irradiation was found in 1995 (Maeda and
Amemiya 1995). The two techniques are complementary with acoustic cavitation
providing a large amount of concentrated energy that is released by hotspots and MW
providing the dielectric and selective heating of solid particles. Combined MW/US
irradiation can be performed either sequentially, by circulating the reacting mixture
through the two compartments, or in simultaneous mode. This latter, synchronous
system, in which the ultrasound horn is placed deep into the reaction liquid within
the MW cavity, is the method of choice.
The yearly number of publications on this subject has been steadily increasing
over the last 20–25 years, as can be seen in Fig. 7.1. This is representative of the
large and constant growth in interest in the widespread applications of simultaneous
MW and US irradiation. The majority of publications deal with extraction, while
organic synthesis, biodiesel production and sample preparation for chemical analysis
attract constant attention. Furthermore, interest in food applications and nanoparticle
production has been growing over the last decade.
Katia Martina contributed to this chapter.
© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2018
J.-M. Lévêque et al., Organic Sonochemistry, Ultrasound and Sonochemistry,
https://doi.org/10.1007/978-3-319-98554-1_7
99
Hybrid Technologies in Action:
Sonochemistry and Beyond
Abstract In the search for new forms of synergism, chemists have always looked
for novel combinations of tools and processes that may produce improvements in
efficiency and selectivity, principally, but also time frame, safety, costs and sustainability. Ultrasound has been combined with microwave heating either in loop or in
flow mode or simultaneously in batch. Relevant examples are reported on the use of
hybrid reactors under combined ultrasound and microwave irradiation.
7.1 Combined Microwaves/Ultrasound; A Brief
Introduction
The first evidence of the synergistic effect produced by simultaneous
microwave/ultrasound (MW/US) irradiation was found in 1995 (Maeda and
Amemiya 1995). The two techniques are complementary with acoustic cavitation
providing a large amount of concentrated energy that is released by hotspots and MW
providing the dielectric and selective heating of solid particles. Combined MW/US
irradiation can be performed either sequentially, by circulating the reacting mixture
through the two compartments, or in simultaneous mode. This latter, synchronous
system, in which the ultrasound horn is placed deep into the reaction liquid within
the MW cavity, is the method of choice.
The yearly number of publications on this subject has been steadily increasing
over the last 20–25 years, as can be seen in Fig. 7.1. This is representative of the
large and constant growth in interest in the widespread applications of simultaneous
MW and US irradiation. The majority of publications deal with extraction, while
organic synthesis, biodiesel production and sample preparation for chemical analysis
attract constant attention. Furthermore, interest in food applications and nanoparticle
production has been growing over the last decade.
Katia Martina contributed to this chapter.
© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2018
J.-M. Lévêque et al., Organic Sonochemistry, Ultrasound and Sonochemistry,
https://doi.org/10.1007/978-3-319-98554-1_7
99