Ultrasound assisted alkaline hydrolysis of poly(ethylene terephthalate) in presence of phase transfer catalyst

Paliwal, Nutan Rajesh; Mungray, Arvind Kumar

doi:10.1016/j.polymdegradstab.2013.06.030

Cited by 63 publications

(52 citation statements)

References 23 publications

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“…transesterification for the production of biodiesel, hydrolysis for degradation of compounds 85 including polymers, 86 acid or base-catalyzed methanolysis, 87 oxidative desulfurization, 88 demulsification 89 and nanoemulsification, 90 amongst others). transesterification for the production of biodiesel, hydrolysis for degradation of compounds 85 including polymers, 86 acid or base-catalyzed methanolysis, 87 oxidative desulfurization, 88 demulsification 89 and nanoemulsification, 90 amongst others).…”

Section: Ultrasound Phase Transfer Catalysismentioning

confidence: 99%

Ultrasonically treated liquid interfaces for progress in cleaning and separation processes

Radziuk

Möhwald

2016

Phys. Chem. Chem. Phys.

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Ultrasound and acoustic cavitation enable ergonomic and eco-friendly treatment of complex liquids with outstanding performance in cleaning, separation and recycling of resources. A key element of ultrasonic-based technology is the high speed of mixing by streams, flows and jets (or shock waves), which is accompanied by sonochemical reactions. Mass transfer across the phase boundary with a great variety of catalytic processes is substantially enhanced through acoustic emulsification. Encapsulation, separation and recovery of liquids are fast with high production yield if applied by ultrasound. Here we discuss the state of knowledge of these processes by ultrasound and acoustic cavitation from a perspective of a physico-chemical model in order to predict and control the outcome. We focus on the physical interpretation and quantification of ultrasonic parameters and properties of liquids to understand the chemistry of liquid/liquid interfaces in acoustic fields. The roles of thermodynamic enthalpy and entropy (incl. Laplace and osmotic pressure) in the context of sonochemical reactions (separation, catalysis, degradation, cross-linking, ion exchange and phase transfer) are outlined. The synergy of ultrasound and electric fields or continuous flow chemistry for cleaning and separation via emulsification is highlighted by specific strategies involving polymers and ultrasonic membranes.

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Section: Ultrasound Phase Transfer Catalysismentioning

confidence: 99%

Ultrasonically treated liquid interfaces for progress in cleaning and separation processes

Radziuk

Möhwald

2016

Phys. Chem. Chem. Phys.

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“…Recycling of PET through depolymerization has been extensively studied and reviewed due to the large volumes of PET bottles, which are creating a fast-growing waste problem (Al-Sabagh et al 2016;Chen et al 2011;Dutt and Soni 2013;George and Kurian 2014;Geyer et al 2016;Paliwal and Mungray 2013;Sinha et al 2010). There are three main chemical degradation methods for PET; hydrolysis (acid, neutral, or alkaline), alcoholysis (Oakley et al 1993), and glycolysis (Viana et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Development of an efficient route for combined recycling of PET and cotton from mixed fabrics

et al. 2017

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Most textile waste is either incinerated or landfilled today, yet, the material could instead be recycled through chemical recycling to new high-quality textiles. A first important step is separation since chemical recycling of textiles requires pure streams. The focus of this paper is on the separation of cotton and PET (poly(ethylene terephthalate), polyester) from mixed textiles, so called polycotton. Polycotton is one of the most common materials in service textiles used in sheets and towels at hospitals and hotels. A straightforward process using 5-15 wt% NaOH in water and temperature in the range between 70 and 90°C for the hydrolysis of PET was evaluated on the lab-scale. In the process, the PET was degraded to terephthalic acid (TPA) and ethylene glycol (EG). Three product streams were generated from the process. First is the cotton; second, the TPA; and, third, the filtrate containing EG and the process chemicals. The end products and the extent of PET degradation were characterized using light microscopy, UV-spectroscopy, and ATR FT-IR spectroscopy, as well as solution and solid-state NMR spectroscopy. Furthermore, the cotton cellulose degradation was evaluated by analyzing the intrinsic viscosity of the cotton cellulose. The findings show that with the addition of a phase transfer catalyst (benzyltributylammonium chloride (BTBAC)), PET hydrolysis in 10% NaOH solution at 90°C can be completed within 40 min. Analysis of the degraded PET with NMR spectroscopy showed that no contaminants remained in the recovered TPA, and that the filtrate mainly contained EG and BTBAC (when added). The yield of the cotton cellulose was high, up to 97%, depending on how long the samples were treated. The findings also showed that the separation can be performed without the phase transfer catalyst; however, this requires longer treatment times, which results in more cellulose degradation.

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“…Having had some superior advantages, including high reactivity, recyclability, nontoxicity, and ease of separation, hydrotalcite was nominated as an effective catalyst. Paliwal and Mungray 108 examined catalytic alkaline hydrolysis of post‐consumer PET waste with or without ultrasound assistance. To transform PET into TPA and EG, NaOH as alkali and tetrabutylammonium iodide (TBAI) as phase transfer catalyst were used under a 20 kHz ultrasound.…”

Section: Chemical Recycling Of Petmentioning

confidence: 99%

Chemical recycling ofPET: A stepping‐stone toward sustainability

Shojaei

Abtahi

Najafi

2020

Polymers for Advanced Techs

168

113

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This paper focuses explicitly on the chemical approaches involved in the recycling of polyethylene terephthalate (PET). Due to the high rate of consumption as well as nonbiodegradability, PET plays a crucial role as one of the most significant sources of accumulated waste in the landfill which jeopardizes our planet. To address this issue as well as increased environmentally conscious, running out of landfill space, natural resource, and energy conservation, and producing value-added chemicals to use as building block or co-products, the chemical recycling methods have been evolved. Therefore, there has been an attempt to have a comprehensive review of the five types of conventional recycling methods namely hydrolysis, methanolysis, glycolysis, aminolysis, and ammonolysis studied by researchers over the last two decades. In this regard, the influence of diverse depolymerization reaction variables for instance, traditional catalyst, temperature profile, ionic liquid catalysts, phase transfer catalyst, microwave assistance, etc was reported. Moreover, the upsides and downsides of each technique were considered.

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Ultrasound assisted alkaline hydrolysis of poly(ethylene terephthalate) in presence of phase transfer catalyst

Cited by 63 publications

References 23 publications

Ultrasonically treated liquid interfaces for progress in cleaning and separation processes

Ultrasonically treated liquid interfaces for progress in cleaning and separation processes

Development of an efficient route for combined recycling of PET and cotton from mixed fabrics

Chemical recycling ofPET: A stepping‐stone toward sustainability

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