Salicylaldehyde-formaldehyde novolacs and their chelated complexes: synthesis and characterization

Abstract

Novolacs based on salicylaldehyde-formaldehyde condensation reaction have been prepared using formic acid, oxalic acid and sulphuric acid as catalysts at 95-100°C. A non-catalysed novolac is also prepared at 250°C in a sealed capsule. Chelates of the novolac obtained using oxalic acid catalyst have been prepared with magnesium, iron, lead and copper. The novo lacs and the metal chelates have been tested for thermal stability in air and nitrogen atmosphere. Chelated novolacs are stable in air at temperatures which are 50°C higher than the decomposition temperatures of the corresponding non-chelated novolacs. Novolacs have been characterised by molecular weight, viscosity measurements and IR/¹H NMR spectroscopic methods.