Title : Effective and green catalysts for the chemical depolymerisation of polyethylene terephthalate plastic bottle waste into its monomers and other products
Abstract:
The chemical business is becoming more environmentally sensitive. The adopted measure for catalytic chemical processes is the choice of suitable and environmentally friendly catalysts in place of noble single-use metals. In this study, various catalysts that are used to chemically recycle polyethylene terephthalic plastic (PET) bottle trash into monomers and other products were evaluated for their potential environmental effects related to their use and disposal. The desire to reduce environmental toxins and necessitate the use of environmentally friendly alternatives. The catalytic chemical processes taken into account include the depolymerization of PET bottle waste into its monomers and other products through solvolysis of the polymeric materials with excess digestive reagents like glycols (glycolysis), water, acid, and alkaline (hydrolysis), amines (aminolysis), alcohols like methanol, ethanol, etc. (alcohololysis), and ammonia (ammonolysis). Hybrid processes including glycolysis-hydrolysis, methanolysis-hydrolysis, and glycolysis-methanolysis, as well as chemical-mechanical ones (alkaline hydrolysis-extrusion), are also being taken into account. The results of some reactions were presented based on the process, reagents, operating conditions, primary products, and secondary products. The types of catalysts used were considered, and they are organometallic catalysts (heavy metal salts), non-toxic metal salts (ionic liquid) catalysts, deep eutectic solvent catalysts, re-generated or recoverable catalysts, large surface area catalysts, and other types of catalysts. Also, in consideration are reactants, reactant ratio (w/w), catalyst/special condition, catalyst/PET (w/w) ratio, temperature (oC), pressure (atm), time (min.),PET conversion (%), product yields (%), and product selectivity (%), respectively. The analysis of the author's works offers us a variety of catalysts, with zinc acetate serving as the most effective organometallic catalyst, to eco-friendly ones like sodium carbonate, and modern ionic liquid catalysts. It demonstrates the basis for selecting a catalyst based on its capacity to increase reaction rates as well as on factors such as recyclability, usability, and eco-friendliness, as in the case of liquid ionic catalysts in the recycling of PET chemicals as evaluated in this work. To manage this, it is necessary to discuss various catalyst types and their effects on the environment in order to choose the most successful catalyst for chemical processing operations.
Audience Takeaway Notes:
- The audience will be able to select the best catalyst for their chemical recycling of polyethylene terephthalate plastic bottle waste, as well as other processes.
- The audience will be able to identify the catalyst with the best yield and selectivity.
- It will promote the best output for the audience at their job.
- It is research that other faculty could use to expand their research or teaching. Chemistry and other related departments can use it.
- It does provide a practical solution to a problem that could simplify or make a designer’s job more efficient.
