Chemistry Reference
In-Depth Information
Scheme 5.1
Synthesis route of ester quaternary ammonium surfactants (C01-C04)
Rosin-based surfactants can be designed through modification of the carboxylic acid
group or hydrophenanthrene group in the molecule. The tricyclic hydrophenanthrene
structure can be modified by an acrylic group through the Diels-Alder addition
reaction, which produces dicarboxylic acids of rosin. Wang and co-workers reported
that a novel bipyridine quaternary ammonium salt cationic surfactant (C05) was
prepared by acrylic-modified rosin (
Scheme 5.2)
. The intermediate reacted with thionyl
chloride to form a chloride intermediate, after quaternisation to form rosin-based
bora type dicationic compounds [13].
Scheme 5.2
Synthesis route of bipyridine quaternary ammonium surfactant (C05)
Under classical conditions, the reactions for synthesising cationic surfactants require
a long reaction time (from 24 to 48 h) to complete the quaternisation reaction,
which results in a lower total yield of the final products and the production of more
byproducts. Microwave activation, as a nonconventional energy source, has become
a very popular and useful technology in organic chemistry [14]. Chemical reactions
brought about by microwave irradiation have gathered momentum in recent years
mainly because of their simplicity, high yield, short time span, and ecofriendly
conditions [15-16].
Gemini surfactants have attracted great interest in recent years. They are made up of
two amphiphilic moieties connected at the head group by a spacer group [17]. Gemini
