A sustainable
and renewable biobased polyester polyol for polyurethane
production was synthesized through the esterification of azelaic acid
and sorbitol catalyzed by tin(II) oxide in a batch system. The studies
on chemical equilibrium, reaction kinetics and important operating
parameters were carried out. The temperature, molar ratio of sorbitol
to azelaic acid and catalyst loading were varied in order to determine
the best reaction conditions. The polyester polyol synthesized was
tested for its fatty acid content through titration. The best operating
condition found was at reaction temperature of 433 K, sorbitol to
azelaic acid molar ratio of 4:1 and catalyst loading of 2 wt %, yielding
72% azelaic acid conversion after 6 h of reaction. The presence of
minute amount of sorbitan and isosorbide inferred the potential of
sorbitol-based branched polyester formation with its backbone incorporated
with these sorbitol anhydrides. The equilibrium study validated the
endothermicity of the reaction. Meanwhile, the kinetic data well fitted
to the Langmuir–Hinshelwood Hougen Watson (LHHW) model with
the activation energy of 14.43 kJ/mol.