Petrochemical Engineering Duhok Polytechnic University Name: Safwan Kamal Askender Stage: 3 Subject: Petrochemical Date: 26/4/2021  Objective: Recycled polyethylene terephthalate (PET) by a depolymerization reaction and use of the product for the synthesis of a diester of high added value. Highlights: Plastics are important in our society providing a range of benefits. Waste plastics, nowadays, burden the marine and terrestrial environment. Additives and PoTSs create complications in all stages of plastics lifecycle. Inappropriate use, disposal and recycling may lead to undesirable release of PoTSs. Sound recycling of plastics is the best waste management and sustainable option. Introduction: Global plastic demand is dominated by thermoplastic types of polypropylene (PP) (21%), low -and linear lowdensity polyethylene (LDPE and LLDPE) (18%), polyvinyl chloride (PVC) (17%), and high-density polyethylene, (HDPE) (15%). Other plastic types with high demand are polystyrene (PS), and expandable PS (8%), polyethylene terephthalate (PET) (7%, excluding PET fibre) and the thermosetting plastic polyurethane. Plastic polymers are not only used for consumer products but also to make synthetic fibres, foams, coatings, adhesives and sealants,  which are used in numerous applications . In Europe, the use of plastics is mostly dominated by packaging (38%), followed by building and construction (21%), automotive (7%), electrical and electronic (6%), and other sectors (28%), such as medical and leisure, Polyethylene terephthalate (sometimes written poly(ethylene terephthalate)), commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is the most common thermoplastic polymer resin of the polyester family and is used in fiber for clothing, containers for liquids and foods, and thermoforming for manufacturing, The confusion seems to come from PET's chemical name, polyethylene terephthalate. Despite the suffix, PET is not a plasticizer phthalate. Phthalates are low molecular weight monoesters made from ortho-phthalic acid. PET is a high molecular weight polyester made from tere-phthalic acid. Benefit of plastic: Plastics are important in our society providing a range of benefits for human health and the environment. For example Plastic packaging protects food and goods from getting wasted and/or contaminated, thereby saving resources. The light weight of plastic packaging compared to other materials saves fuel and decreases emissions during transportation. Plastic water supply systems and storage containers/tanks can provide clean water. Low-density plastic materials, used as replacements for metals or ceramics in cars and aircraft, save fuel and decrease emissions. Plastic protective clothing and safety equipment (e.g. fire proof materials, helmets, air bags) prevent injuries. Plastic products for medical applications contribute to improved heath (e.g. blood pouches, tubings, disposable syringes, prosthesis)  Reagent & material 12345678- Bottle of water (PET) pentan1-ol KOH (0.079 mol) Water HCl Acetone H2SO4 MeOH Procedure: A) Preparation of PET samples From bottles of soda or mineral water previously cleaned without labels, using scissors, cut plastic into small pieces to obtain a mass of approximately (5 g). B) Hydrolysis of PET samples (preparation of Terephthalic Acid) 1. In round-bottom flask, add (35 ml) of pentan-1-ol (mixture of isomers or pentan1-ol. 2. Add (5 g) of PET (0.052 mol equivalent ester), and (4.4 g) of KOH (0.079 mol) in the round-bottom flask. 3. Reflux the mixture with magnetic stirring. While at first the polymer does not dissolve, shortly after dissolution a dense white emulsion forms. Note (If magnetic stirring is stopped by the viscosity of the reaction crude, add more solvent in portions of (5 ml) of pentan-1-ol). 4. Once the stirring resumes, maintain the reflux for (1 h) 5. After reflux, cool the reaction to room temperature.  6. Add (25 ml) of water so that the white solid (terephthalate potassium salt) is dissolved. 7. Filtration to remove any remaining suspended solid, (it’s preferred to use Buchner funnel to filtration because the water/pentan-1-ol mixture filters very slowly by gravity). 8. Transfer the filtrate to a separating funnel. Decant the aqueous (lower) layer and wash the organic (top) with another (25 ml) of water. 9. Collect in a beaker both aqueous layers, and add diluted HCl very slowly with magnetic stirring to neutrality. Polymer synthesis and characterization (If the acid is added too quickly, a solid crystal of very small size will form and will be difficult to filter). 10. Once the terephthalic acid has precipitated, filter the crystals (using Buchner funnel) and wash with of (5-10 ml) of acetone. 11.Weigh, calculate yield, and store for the next step Producing Dimethyl Terephthalate : 1. In a round-bottom flask, add (2.5 g) of terephthalic acid and (20 ml) MeOH. 2. Cool the mixture in an ice bath and slowly add with a dropper (3 ml) of concentrated H2SO4. (If the acid is added too quickly, a solid crystal of very small size will form and will be difficult to filter). 3. Add a stir bar into the flask and reflux (using a drying tube) for (60 min). 4. After reflux, cool the reaction to room temperature. 5. Filter the resulting solid (using Buchner funnel). 6. Recrystallize the impure product from dichloromethane.  7. Weigh, and calculate the yield. Calculation: Discussion: What products are made from polyethylene terephthalate? Products commonly made from recycled PET include new PET bottles and jars, carpet, clothing, industrial strapping, rope, automotive parts, fiberfill for winter jackets and sleeping bags, construction materials, and protective packaging. After preparing solution in part (C) we put solution into cold water during adding H2SO4? To remove heat from solution cuz the are exothermic solution. What plastics contain phthalates? Some phthalates are in polyvinyl chloride plastics, which are used to make products such as plastic packaging, garden hoses, and medical tubing. People are exposed to phthalates by eating and  drinking foods that have contacted products containing phthalates. Do plastic water bottles have phthalates? Most plastic wraps, water bottles, and food containers are phthalate-free. Is PET plastic safe? Previous research has focused on plastics containing the chemical bisphenol-a (BPA). During that time regular PET plastic water bottles have maintained a reputation as safe, at least as far as human health is concerned. But new evidence suggests that PET, or polyethylene terephthalate, may not be so benign after all. Chemical recycling can turn plastic back into its original components? Chemical recycling can turn plastic back into its original components, from which new plastic can be made. Chemically recycled plastic is of high quality and can be a drop-in substitute for plastic from virgin fossil feedstock even for sensitive applications, such as food packaging and medical products.