Chemistry Reference
In-Depth Information
5.2.1.2 Dehydroabietylamine Derived Quaternary Ammonium Salts
The most widely used starting materials for the synthesis of rosin-based quaternary
ammonium compounds are rosin amine or dehydroabietylamine [24]. Rosin amine
or dehydroabietylamine can be used as starting materials to prepare tertiary amine in
the presence of formaldehyde and formic acid, and then the rosin based quaternary
ammonium salts can be prepared in a standard procedure called quaternisation.
N
,
N
-Dimethyldehydroabietylamine (DMDHA) is a very important intermediate for
the synthesis of rosin-based cationic surfactants. There are two methods to synthesise
DMDHA. It can be synthesised under mild conditions, in which dehydroabietylamine,
formic acid and formaldehyde solution are refluxed together at a temperature of 65 ℃
for about 5-7 h, which gives a yield of 70-80%. The other method is hydrogenation
by formaldehyde under pressure, which gives a yield of 89-94%. Ordinarily the first
method is widely used because of the mild reaction conditions [25-27].
Wang and co-workers reported a series of quaternary ammonium salts (C15-C20)
which were synthesised from dehydroabietylamine by the formic acid and
formaldehyde method (
Scheme 5.10
) at atmospheric pressure [28]. Pan and co-
workers reported four novel chiral quaternary ammonium salts (C21-C24) which
were synthesised from dehydroabietylamine by the method shown in
Scheme 5.11
[29]. Jia and co-workers reported the rosin-based quaternary ammonium gemini
surfactants (C25-C28) which were synthesised from dehydroabietylamine by reaction
with DMDHA and α, ω- bisbromoalkanes (
Scheme 5.12
) [30].
Scheme 5.10
Synthesis of cationic surfactants (C15-C20)
