Abstracts Book - IMRC 2018

• SF3-O057
FLUORINATED LAYERED DOUBLE HYDROXIDES ENHANCE
CATALYSIS OF CYANOETHYLATION OF ALCOHOLS
Mariana Lizeth Diaz Ramirez 1 , Enrique Jaime Lima Muñoz 1
1 Universidad Nacional Autónoma de México, Instituto de Investigaciones en Materiales,
Mexico.
Cyanoethylation of alcohols is a widely used reaction for the synthesis of drug
intermediates and organic compounds of industrial interest. This reaction is
promoted in the presence of a base, which is typically a homogeneous basic
catalyst such as alkali hydroxides or alkoxides. In order to minimize waste
generation, as well as loss of catalyst, different materials have been proposed
as heterogeneous catalysts, which include anion exchange resins, magnesium
oxide 1 and lately, modified layered double hydroxides (LDH). The latter showed
high catalytic activity 2 .
In a recent study, the replacement of structural OH - by F - in LDH has resulted in
the enhancement of the hydrogen bond accepting character and the acidbasicity
of the material 3 .
In this work, LDH were synthesized using both aluminum (Mg-Al) and gallium
(Mg-Ga) as trivalent cation. Furthermore, in order to tune the acid-base
properties materials with partial substitution of the (M(OH) 6 ) 3- octahedra by
(AlF 6 ) 3- were synthesized. These solids were used calcined or activated as
catalysts in the reaction of cyanoethylation of acrylonitrile with methanol.
Activation of the materials was carried out with a thermal treatment followed by
the rehydration of the solids at room temperature. The effect of the amount of
fluorine and the rehydration time on the catalytic activity was evaluated. The
solids that have the highest catalytic activity are the rehydrated ones. It is
observed that the rehydration time has a greater effect in the samples that do
not contain fluorine and that with a longer rehydration time, better catalytic
activity, reaching 97% conversion for the Mg-Ga. It is also noted that the highest
conversion of acrylonitrile is obtained with the Mg-Ga solids, fluorinated or not.
However, for Mg-Ga fluorinated solids, a rehydration time of more than 5 h does
not affect the catalytic activity, that is, for 5 hours an equilibrium has been
reached in the rehydration process.