The kinetics of vanillin sorption by strong basic macro porous anion-exchange resin Marathon MSA

Abstract

In the synthesis of 4-hydroxy-3-methoxybenzaldehyde (vanillin) some side products are formed in
the reaction media so an important task is the elaboration of the procedure for vanillin selective extraction
from technological solutions. It is shown that anion-exchange resins are effective sorbents of hydroxybezaldehydes.
The isotherm of vanillin sorption by macro porous high basic anion-exchange resin Marathon MSA
(Dow Chemical) in OH-form has been obtained in this work using the procedure of variable concentrations.
It is found that sorption has a multimolecular type which deals with a possibility of vanillin molecules to dissociate
in the phase of anion-exchange resin in OH-form and to form vanillate-ions taking part in the anionexchange
reactions. The additional uptake of vanillin caused by physical sorption also takes place in the system
aromatic aldehyde solution – sorbent. Some of the supposed interactions are confirmed by the method of
IR-spectroscopy.
Based on the kinetic curves of hydroxybenzaldehyde sorption by Marathon MSA resin the
equilibrium time in the studied systems is determined for different concentrations and temperatures (298, 308
and 323±2К). It is revealed that sorption equilibrium is reached rather rapidly in comparison with weak basic
resins. The limiting stage of vanillin uptake is estimated using the formal approach of Boyd-Adamson.