Polymeric resin from renewable resources: Studies on polymerization of the phenolic component of coconut shell tar

Abstract

Polymerization of the Phenolic Component of Coconut Shell TarToday there is much discussion on the utilization of renewable resources for polymer a p plications.This is partly due to the recognition that the supply of petroleum and coal is limited and that the cost of petrochemicals is on the increase.Thus, biomass which consists mostly of polymers and monomers of natural origin offers itself as a suitable renewable resource.A good number of reviews and research papers have already come up indicating their importance.'"Materials based on the coconut tree form a major renewable resource of the tropical regions of the world.6Of these materials, the coconut shells are available to the tune of about 4.2 million tons per year.6The shells on destructive distillation give (see Fig. 1) coconut shell char, which is used as a filler in plastics and for the development of activated carbon.Coconut shell tar (CST) is a byproduct obtained during the distillation process and was considered as a waste so far.The CST is a tarry oil, dark brown in color with a characteristic unpleasant empyreumatic odor.Except for some identification of the components, not much work has been done on it.It is reported to contain many monomers, the major one being phenolic in n a t ~r e .~ This paper deals with the enrichment and polymerization of the phenolic components of CST. EXPERIMENTAL Materials and MethodsCST was obtained from M/s. Carbo Chemicals Industries Ltd., Calicut, and the same was used without further purification.Phenol (GR) and formaldehyde (AR) were obtained from Glaxo Laboratories.Acetone (GR), oxalic acid (GR), sodium hydroxide (GR), and hexamethylene tetramine were obtained from Sarabhai M. Chemicals. Isolation and Separation of Phenolic Components of CSTCST (100 mL) was distilled at atmospheric pressure, and fractions coming out at lOWC, at 103-10YC, and at 118-12WC were collected.The first fraction was water (22%), the second fraction was crotonaldehyde (3%), and the third fraction was acetic acid (11%).The residue was refluxed with 3% sodium hydroxide for 2 h and neutralized with glacial acetic acid.It was dissolved in acetone and filtered to remove free carbon.The filtrate, after the removal of acetone, was used for polymerization. PolymerizationA two-stage Novolak resin (PF mol ratio = kO.8)was prepared from CST.A 500-mL resin kettle was fitted with a reflux condenser, stirrer, and thermometer.To the reaction vessel S h e l l ( 1 ton) Uncondensable Charcoal Tar Pyrligneous acid gases (300 kg) (300 kg) (100 kg) (300 kg) Fig. 1.Coconut shell distillation products.