Production Of Polyethylene Terephthalate Research Articles

Engineering Pseudomonas putida KT2440 for efficient ethylene glycol utilization

Ethylene glycol is used as a raw material in the production of polyethylene terephthalate, in antifreeze, as a gas hydrate inhibitor in pipelines, and for many other industrial applications. It is metabolized by aerobic microbial processes via the highly toxic intermediates glycolaldehyde and glycolate through C2 metabolic pathways. Pseudomonas putida KT2440, which has been engineered for environmental remediation applications given its high toxicity tolerance and broad substrate specificity, is not able to efficiently metabolize ethylene glycol, despite harboring putative genes for this purpose. To further expand the metabolic portfolio of P. putida, we elucidated the metabolic pathway to enable ethylene glycol via systematic overexpression of glyoxylate carboligase (gcl) in combination with other genes. Quantitative reverse transcription polymerase chain reaction demonstrated that all of the four genes in genomic proximity to gcl (hyi, glxR, ttuD, and pykF) are transcribed as an operon. Where the expression of only two genes (gcl and glxR) resulted in growth in ethylene glycol, improved growth and ethylene glycol utilization were observed when the entire gcl operon was expressed. Both glycolaldehyde and glyoxal inhibit growth in concentrations of ethylene glycol above 50 mM. To overcome this bottleneck, the additional overexpression of the glycolate oxidase (glcDEF) operon removes the glycolate bottleneck and minimizes the production of these toxic intermediates, permitting growth in up to 2 M (~124 g/L) and complete consumption of 0.5 M (31 g/L) ethylene glycol in shake flask experiments. In addition, the engineered strain enables conversion of ethylene glycol to medium-chain-length polyhydroxyalkanoates (mcl-PHAs). Overall, this study provides a robust P. putida KT2440 strain for ethylene glycol consumption, which will serve as a foundational strain for further biocatalyst development for applications in the remediation of waste polyester plastics and biomass-derived wastewater streams.

FEATURES OF THE RESPONSE OF THE BLOOD SYSTEM IN PHTHALATES PRODUCTION WORKERS

Introduction. Phthalates are substances widely used as plasticizers for the production of various industrial, domestic, food and medical polymer materials. Possessing high volatility, solubility, a wide range of toxic effects, phthalates represent a serious danger to human health. Goal. Identify the characteristics of donosological forms of impaired health. Material and methods. A special clinical and functional examination of the aparatics for the first time started their work in the production of terephthalic acid (TPA), purified terephthalic acid (oTPA) and polyethylene terephthalate (PET) in the dynamics of 5 years of operation of the enterprise POLYEF. Hygienic, hematological, cytochemical and biochemical studies were performed for workers with a primary 5-year experience in this industry. Results. It is established that the chemical factor is represented by a complex of harmful substances of 1 to 4 hazard classes, among which there are substances of irritating, general toxic, allergenic action. The production of phthalates is characterized by an increased content of TPA from 1.5 to 2.8 MPC. Discussion. The working conditions of the apparatchiks in all industries are estimated as harmful to the third degree - 3.3. Among those who have worked for 5 years, about a third of workers are recognized with clinical and functional disorders. For 5 years of work, two of the first three come into contact with phthalates revealed changes in the blood system that go beyond physiological fluctuations. Most workers have anemia, reticulocytosis, thrombocytopenia, eosinophilia, lymphocytosis, decreased activity of enzymes. Conclusions. The introduction of a differentiated approach, taking into account the results of the clinical, hygienic and laboratory-diagnostic studies carried out, will allow monitoring of the health status of workers in the production of TFA and PET, identify early donosological signs of health disorders, and adequately form high-risk groups for conducting therapeutic and preventive measures.

Profitability and environmental friendliness of a closed-loop supply chain for PET components: A case study of the Mexican automobile market

Each year, a high number of automobiles need to be disposed of in Mexico; leading to a high amount of automotive thermoplastic polymer waste. This situation makes Mexico an interesting country to deploy a closed-loop supply chain (CLSC) for the chemical recycling of this kind of waste. Despite being an interesting case, no study has been carried out until now evaluating the potential of a CLSC under the umbrella of the Mexican automobile market. This study is the first one that evaluates the profitability and environmental friendliness (energy consumed and CO2 generated) of a closed-loop supply chain (CLSC) for the chemical recycling of Polyethylene terephthalate (PET) seats within the Mexican automobile market. The originality of this study also relies on being the first one that considers at the same time, the influence of Mexico’s current political, social, legal, and technological conditions on the CLSC’s profitability and environmental friendliness, as well as, on being the first that quantifies this influence in costs, CO2 footprint, and consumed energy terms. This approach allows the easy identification of the CLSC’s profitability and environmental friendliness key drivers; making possible the design of effective strategies to improve the CLSC’s performance. The study uses stakeholder mapping, as well as, Political, Economic, Social, Technological, Legal and Environmental Analysis (PESTLE) as data analysis tools. It shows that the studied CLSC is profitable under the umbrella of Mexico’s current infrastructure, political, and legal frameworks. Regarding environmental friendliness, the studied CLSC consumes 79% less energy and generates 73% less CO2 than those associated with the production of PET using a forward supply chain. Keeping in mind this study’s results, it provides evidence about CLSCs being both profitable and environmentally friendly under the umbrella of emerging economies, such as Mexico.

Glycolytic depolymerization of PET waste using MP-diol and utilization of recycled product for UV-curable wood coating

Polyethylene terephthalate (PET) waste recycling has become a worldwide research interest for industries and academic institutes due its inevitable environmental impact. The main objective of current research work is to target efficient recycling of PET waste from mineral water bottles by the glycolysis method and subsequent use of the recycled product for value-added coating application. In the present study, we report on MP-diol (2-methyl-1,3-propanediol) which is not explored much for the chemical recycling of PET, having a branched aliphatic diol with two primary hydroxyls, for glycolysis reaction. The reaction parameters were optimized for microwave-assisted technique by varying the ratio of raw materials, reaction time, temperature, and power. The reaction parameters were optimized, and the recycled oligomeric product (OPETMPD) was separated, purified, and characterized by chemical and spectroscopic methods. Subsequently, dimethacrylated oligoesters of PET oligomer (UV oligomer) were synthesized by methacrylation of the glycolyzed PET product (OPETMPD). The synthesized UV oligomer was evaluated using chemical and spectroscopic methods. Ultraviolet (UV) radiation-curable formulations were prepared using synthesized UV oligomer and applied on wooden panels. The coatings were cured using UV-curing machine and evaluated for their performance properties. The partial replacement of UV oligomer in UV formulations exhibited comparative coating performance properties with respect to conventional UV formulation.

Impact on the Polyester Value Chain of Using p-Xylene Derived from Biomass

Life cycle assessment has been used to investigate the environmental impacts associated with using p-xylene produced from biomass rather than from the processing of naphtha in the production of polyethylene terephthalate (PET). The cases investigated were for polymer production and distribution facilities in the United States. The types of biomass considered were corn stover, willow, and sugar cane (both juice and bagasse). The best case for minimizing global warming potential and fossil energy use involved producing p-xylene from sugar cane juice, while the sugar cane bagasse was burnt to generate electricity. Compared with conventional processing, a net reduction in global warming potential of 87% and a 26% reduction in fossil energy use were obtained. Furthermore, it has been shown that savings can be made by producing ethylene glycol from sugar cane bioethanol.1 This would enable the production of a PET bottle sourced completely from biomass. The production of such a bottle would result in an overall ...

Field-portable-XRF reveals the ubiquity of antimony in plastic consumer products

Very little systematic information exists on the occurrence and concentrations of antimony (Sb) in consumer products. In this study, a Niton XL3t field-portable-X-ray fluorescence (FP-XRF) spectrometer was deployed in situ and in the laboratory to provide quantitative information on Sb dissipated in plastic items and fixtures (including rubber, textile and foamed materials) from the domestic, school, vehicular and office settings. The metalloid was detected in 18% of over 800 measurements performed, with concentrations ranging from about 60 to 60,000μgg-1. The highest concentrations were encountered in white, electronic casings and in association with similar concentrations of Br, consistent with the use of antimony oxides (e.g. Sb2O3) as synergistic flame retardants. Concentrations above 1000μgg-1, and with or without Br, were also encountered in paints, piping and hosing, adhesives, whiteboards, Christmas decorations, Lego blocks, document carriers, garden furniture, upholstered products and interior panels of private motor vehicles. Lower concentrations of Sb were encountered in a wide variety of items but its presence (without Br) in food tray packaging, single-use drinks bottles, straws and small toys were of greatest concern from a human health perspective. While the latter observations are consistent with the use of antimony compounds as catalysts in the production of polyethylene terephthalate, co-association of Sb and Br in many products not requiring flame retardancy suggests that electronic casings are widely recycled. Further research is required into the mobility of Sb when dissipated in new, recycled and aged polymeric materials.

Renewable p‐Xylene from 2,5‐Dimethylfuran and Ethylene Using Phosphorus‐Containing Zeolite Catalysts

Abstractp‐Xylene is a major commodity chemical used for the production of polyethylene terephthalate, a polymer with applications in polyester fibers, films, and bottles. The Diels–Alder cycloaddition of 2,5‐dimethylfuran and ethylene and the subsequent dehydration of the cycloadduct intermediate is an attractive reaction pathway to produce renewable p‐xylene from biomass feedstocks. However, the highest yields reported previously do not exceed 75 %. We report that P‐containing zeolite Beta is an active, stable, and selective catalyst for this reaction with an unprecedented p‐xylene yield of 97 %. It can catalyze the dehydration reaction selectively from the furan‐ethylene cycloadduct to p‐xylene without the production of alkylated and oligomerized products. This behavior is distinct from that of Al‐containing zeolites and other solid phosphoric acid catalysts and establishes a commercially attractive process for renewable p‐xylene production.

Biomass‐Derived Renewable Aromatics: Selective Routes and Outlook for p‐Xylene Commercialisation

Methylbenzenes are among the most important organic chemicals today and, among them, p-xylene deserves particular attention because of its production volume and its application in the manufacture of polyethylene terephthalate (PET). There is great interest in producing this commodity chemical more sustainably from biomass sources, particularly driven by manufacturers willing to produce more sustainable synthetic fibres and PET bottles for beverages. A renewable source for p-xylene would allow achieving this goal with minimal disruption to existing processes for PET production. Despite the fact that recently some routes to renewable p-xylene have been identified, there is no clear consensus on their feasibility or implications. We have critically reviewed the current state-of-the-art with focus on catalytic routes and possible outlook for commercialisation. Pathways to obtain p-xylene from a biomass-derived route include methanol-to-aromatics (MTA), ethanol dehydration, ethylene dimerization, furan cycloaddition or catalytic fast pyrolysis and hydrotreating of lignin. Some of the processes identified suggest near-future possibilities, but also more speculative or longer-term sources for synthesis of p-xylene are highlighted.

Time, Temperature and Amount of Distilled Water Effects on the Purity and Yield of Bis(2-hydroxyethyl) Terephthalate Purification System

Polyethylene terephthalate (PET) bottle is one of the common plastic wastes existed in the municipal solid waste in Malaysia. One alternative to solve the abundant of PET wastes is chemical recycling of the wastes to produce a value added product. This technology not only can decrease the PET wastes in landfill sites but also can produce many useful recycled PET products. Bis(2-hydroxyethyl) terephthalate (BHET) obtained from glycolysis reaction of PET waste was purified using crystallization process. The hot distilled water was added to glycolysis product followed by cooling and filtration to extract BHET in white solid form from the product. The effect of three operating conditions namely crystallization time, crystallization temperatures and amount of distilled water used to the yield of crystallization process were investigated. The purity of crystallization products were analyzed using HPLC and DSC. The optimum conditions of 3 hours crystallization time, 2 °C crystallization temperature and 5:1 mass ratio of distilled water used to glycolize solid gave the highest yield and purity of the crystallization process. © 2015 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Reducing water and energy consumption in chemical industry by sustainable production approach: a pilot study for polyethylene terephthalate production

In this study, a polyethylene terephthalate manufacturing plant was subjected to environmental performance evaluation and analyses/benchmarking of water consumption. The objective was to determine processes/practices where significant water and related energy saving potential was present. Based on evaluations and analyses, a technology change was realized in heat transfer systems from water-to air-cooled process. As a result of the applications, soft cooling water consumption of the company was reduced by 46.7% which corresponds to water saving of 151,428 m3/year. Moreover, 117,848 kWh/year of energy was saved due to electricity saving in electric motors of pumps of heat transfer systems as well as pumps/fans of cooling towers. Owing to the improved energy efficiency, total carbon emissions of the company was reduced by 69,530 kg CO2/year. Auxiliary material consumption was also reduced since the maintenance requirements of heat transfer pumps were minimized. The total cost saving was 104,905 $/year, while the payback period was calculated as 6 months. This study was conducted to be used as a successful model to increased water and energy efficiency in manufacturing industries based on systematic environmental performance evaluations and benchmarking. Furthermore, it could serve as a building block in Turkey for the integration of cleaner and sustainable production approach into national agenda which is currently being structured by the European Union harmonization efforts of this country.

System Dynamics Approach in LCA for PET-Renewable Raw Materials Impact

It has been shown that system dynamics and life-cycle analysis together provide an analytical tool to study different impacts between variables in decision-making process. This paper presents an application of this approach toward to a plastic material of quotidian use, considering both, a production chain using renewable resources and petrochemical production of Polyethylene Terephthalate, used as a beverage bottle application, and showing its impacts to the system when production replacement of non-renewable resources is allowed. We have already studied the substitution between different materials: glass and aluminum.

Production of Polyethylene Terephthalate Based Sorbent and its Use for Waste and Surface Water Cleaning from Oil Products

Effective and inexpensive sorbing materials can be manufactured from secondary (recycled) polymers, which will help solve problems of water cleaning and waste recycling. A technology of sorbing material manufacture from polyethylene terephthalate wastes for waste and surface water cleaning is described, and the physicochemical properties of the sorbent and the efficiency of water cleaning from oil products are studied.

Life cycle impact assessment of bio-based plastics from sugarcane ethanol

The increasing production of bio-based plastics calls for thorough environmental assessments. Using life cycle assessment, this study compares European supply of fully bio-based high-density polyethylene and partially bio-based polyethylene terephthalate from Brazilian and Indian sugarcane ethanol with production of their petrochemical counterparts in Europe. Bio-based polyethylene results in greenhouse gas emissions of around −0.75 kg CO2eq/kgpolyethylene, i.e. 140% lower than petrochemical polyethylene; savings on non-renewable energy use are approximately 65%. Greenhouse gas emissions of partially bio-based polyethylene terephthalate are similar to petrochemical production (±10%) and non-renewable energy use is lower by up to 10%, partly due to the low bio-based content of the polymer. Assuming that process energy is provided by combined heat and power reduces the greenhouse gas emissions of partially bio-based polyethylene terephthalate production to a range from −4% (higher) to 15% (lower) compared to petrochemical polyethylene terephthalate depending on the methodological choices made. Production from Brazilian ethanol leads to slightly higher impacts than production from Indian ethanol due to dampening effects of allocation on Indian ethanol produced from sugarcane molasses, different sugarcane pre-harvesting practices and inter-continental transport of Brazilian ethanol to India. Internal technical improvements such as fuel switch, new plants and best available technology offer savings up to 30% in greenhouse gas emissions compared to current production of petrochemical polyethylene terephthalate. The combination of some of these measures and the use of biomass for the supply of process steam can reduce the greenhouse gas emissions even further. In human health and ecosystem quality, the impact of the bio-based polymers is up to 2 orders of magnitude higher, primarily due to pesticide use, pre-harvesting burning practices in Brazil and land occupation. When improvements are assumed across the supply chain, such as pesticide control and elimination of burning practices, the impact of the bio-based polymers can be significantly reduced. Realising such improvements will minimise the greenhouse gas and other emissions and resource use associated with bio-based polyethylene terephthalate and will allow to alleviate further pressure on fragile ecosystems.

Detonation and deflagration characteristics of p-Xylene/gaseous hydrocarbon fuels/air mixtures

p-Xylene is an important intermediate for the production of polyethylene terephthalate, it has growing chemical industrial demand based on the statistics in the last few decades. In the process of producing p-Xylene, gaseous hydrocarbon fuels (e.g., H2, C1–C3) are usually involved, which renders p-Xylene highly possible mix with those gaseous hydrocarbon fuels as leaking occurs, this presents fire or explosion/detonation hazard at some specific conditions. To date, very limited data regarding its detonation and deflagration characteristics are available in previous literatures. In this study, experiments of measuring the overpressure and velocity of p-Xylene/gaseous hydrocarbon fuels (i.e., H2, C2H4, C3H8, CO)/air mixtures are carried out in a vertical detonation tube with an inner diameter of 200mm and a length of 6.5m to explore the detonation and deflagration characteristics of p-Xylene. The experimental results indicate that under the same initiation energy of 0.189MJm−2, pure p-Xylene/air and p-Xylene/CO/air cannot achieve detonation, only deflagrations are observed. However, under this same initiation energy, detonations occur in p-Xylene/H2/air, p-Xylene/C2H4/air and p-Xylene/C3H8/air mixtures. By comparing the combinatorial compositions of p-Xylene along with gaseous hydrocarbon fuels that within which detonation observed, the detonation sensitive of the mixtures in increasing order are obtained as following: p-Xylene/H2/air, p-Xylene/C3H8/air and p-Xylene/C2H4/air. The results also indicate the relative ease that p-Xylene/gaseous hydrocarbon fuel/air can be detonated mainly depends on the detonation sensitive of the gaseous fuel, which is supported by the critical energy of direct detonation initiation and chemical kinetic analysis.

A Theoretical and Experimental Investigation of Wastewater Treatment for a Polyethylene Terephthalate Production Unit

In this research, mathematical modelling of an anaerobic hybrid bioreactor for effluent treatment of a PolyEthylene Terephthalate (PET) unit in a petrochemical complex was performed. The developed model included a combination of a biofilm model for describing the substrate kinetics; a fluidized bed model for determination of species profiles along the reactor length and a bioreactor model for particle distribution inside the reactor. The reactions performed in the bioreactor included; i) the polymers hydrolysis; ii) fermentation of the resulting monomers; iii) the volatile fatty acids fermentation to Acetate and Hydrogen and iv) the Methane formation as the final product. The reactor was divided into n-segments each being fully mixed and the changes of granule densities at each one caused by granules growth were neglected. On the other hand, the experimental data obtained from an industrial unit in which, the pH was controlled by adding NaHCO3 and NaOH while; a mixture of Urea, di-ammonium phosphate and molasses were utilized as substrates. The total flow rate inside the 2,200 m 3 bioreactor was set 180 m 3 /h with 0.7 m/h upflow velocity. The theoretical data determined from the developed model for the volatile fatty acids’ (VFAs) production while the corresponding experimental data obtained from the industrial unit. Moreover, the comparison between the bioreactor effluent’s COD determined through both the theoretical and experimental studies were presented. The current model reproduced the experimental data with mean error of 14 % which considering the complexity of the undertaken system was rather satisfying.

Use of Dimethylterephthalate Production Wastes to Prepare Oligoesters

Two grades of polyols were produced as a result of research performed at the pilot stand in the organic synthesis plant of Mogilevkhimvolokno Corp. They were aromatic oligoesters based on dimethylterephthalate production wastes and vat residues from ethyleneglycol regeneration columns that were used to produce PUR and PUR-PIR hard plastic foams used as thermal insulators, sandwich panels, and other items. Laboratory tests are continuing in order to optimize the syntheses of polyols with different compositions based on dimethyl- and polyethyleneterephthalate production wastes.

Determination of monomers and oligomers in polyethylene terephthalate trays and bottles for food use by using high performance liquid chromatography-electrospray ionization-mass spectrometry

The types and contents of monomers and oligomers in polyethylene terephthalate (PET) food containers were analyzed using HPLC-ESI-MS after being extracted with 50% acetonitrile or dichloromethane using an accelerated solvent extraction unit. The types of cyclic oligomers were classified into first and second series. The first series represented a type of [TG]n composed of terephthalic acid (TPA; T) and monoethylene glycol (EG; G) at a ratio of 1:1. The second series showed a type of [TG]nG in which a single G unit was substituted by diethylene glycol (DEG; GG). The oligomer level extracted using dichloromethane was measured at 4024–11576 mg kg−1. The first series cyclic oligomers, second series cyclic oligomers and linear oligomers constituted 83.0–90.6%, 7.8–14.7% and 1.3–2.8%, of the total extracted oligomers, respectively. The extracted amounts of TPA, monohydroxyethyl terephthalate and bishydroxyethyl terephthalate using 50% acetonitrile were 3.0–28.2 mg kg−1, 16.8–118.2 mg kg−1 and 3.9–26.7 mg kg−1, respectively. The A2, A3, S2 and S3 groups as modified oligomers were detected as 42.9–221.4 mg kg−1, 17.2–250.3 mg kg−1, 1.1–48.1 mg kg−1 and 1.0–19.8 mg kg−1, respectively. The results of this study demonstrate an advanced analytical approach to determine the residual oligomers and monomers in PET products for food use and imply their potential migration to foodstuffs.

ANÁLISE E CONTROLE DOS HIDROCARBONETOS GERADOS NA COMBUSTÃO DOS RESÍDUOS DE PET

Brazilian production of PET (polyethylene terephthalate) in 2010 was of 505,000 tones. The PET waste may be used to generate energy by controlled burning. In this study, emissions of light hydrocarbons generated during combustion of these wastes are characterized. Samples of post-consumer PET bottles were inserted in an electric furnace at temperatures of 600, 800 and 1000°C under an atmosphere of 15% O2 and 85% N2. The effluents were subjected to a SiC filter and channeled into the second furnace at 1000°C. Stainless steel meshes were placed in the second furnace in order to work as catalyst. Gas chromatography is used to evaluate the effluent with and without the catalyst use, wherein is showed a significant reduction in the emissions using the meshes. Results allow a characterization of the hydrocarbons generated during the controlled burning of PET waste providing information for control and recovery of these gases emissions

On the Diels–Alder Approach to Solely Biomass‐Derived Polyethylene Terephthalate (PET): Conversion of 2,5‐Dimethylfuran and Acrolein into p‐Xylene

Polyethylene terephthalate (PET) is a polymeric material with high global demand. Conventionally, PET is produced from fossil-fuel-based materials. Herein, we explored the feasibility of a sustainable method for PET production by using solely bio-renewable resources. Specifically, 2,5-dimethylfuran (derived from lignocellulosic biomass through 5-(hydroxymethyl)furfural) and acrolein (produced from glycerol, a side product of biodiesel production) were converted into the key intermediate p-xylene (a precursor of terephthalic acid). This synthesis consists of a sequential Diels-Alder reaction, oxidation, dehydration, and decarboxylation. In particular, the pivotal first step, the Diels-Alder reaction, was studied in detail to provide useful kinetic and thermodynamic data. Although it was found that this reaction requires low temperature to proceed efficiently, which presents a limitation on economic feasibility on an industrial scale, the concept was realized and bio-derived p-xylene was obtained in 34% overall yield over four steps.

Recovery of Terephthalic Acid from Alkali Reduction Wastewater by Cooling Crystallization

AbstractA process for the recovery and purification of terephthalic acid (TA) from alkali reduction wastewater is reported. TA was first precipitated from alkali reduction wastewater by acidification with sulfuric acid, and then the produced crude TA was dissolved in dimethylacetamide (DMA) so that crude TA could be purified from the solution by cooling crystallization. The results indicated that acidification could reduce the chemical oxygen demand of the wastewater by 83 %, and the purity of TA by crystallization could reach 99.91 %. A correlation was proposed in describing the solubility of crude TA in DMA from 303.4 to 358.65 K, which gives a mean relative discrepancy of less than 1.14 %. The cooling rate of the mother liquor had a large influence on the crystal size distribution. At an average cooling rate of 1.18 K min–1, the particle size distribution of TA was narrow and the average size was about 100 μm. In a bench‐scale study, it was demonstrated that the crystallized product can be recycled as the raw material for polyethylene terephthalate production.