RESUMEN

Carbohydrates, one of the most abundant biomolecules found in nature, have been seen traditionally as a dietary component of foods. Recent findings, however, have unveiled their medicinal potential in the form of carbohydrates-derived drugs. Their remarkable structural diversity, high optical purity, bioavailability, low toxicity and the presence of multiple functional groups have positioned them as a valuable scaffold and an exciting frontier in contemporary therapeutics. At present, more than 170 carbohydrates-based therapeutics have been granted approval by varying regulatory agencies such as United States Food and Drug Administration (FDA), Japan Pharmaceuticals and Medical Devices Agency (PMDA), Chinese National Medical Products Administration (NMPA), and the European Medicines Agency (EMA). This article explores an overview of the fascinating potential and impact of carbohydrate-derived compounds as pharmacological agents and drug delivery vehicles.

RESUMEN

Poly(ethylene terephthalate) (PET) is one of the most widely used polymeric materials in chemical industry representing about 13% of the world's production. With the exponentially increasing consumption of plastics combined with its non-biodegradability, the accumulation of plastic waste in the environment rises steeply and its recycling has attracted enormous attention among researchers in recent years. In this present work, we describe bamboo leaf ash (BLA) as a bio-waste derived recyclable heterogeneous catalyst for the depolymerization of waste PET. The prepared catalyst was characterized by FT-IR, XRD, SEM, TEM, EDX, TGA and BET analyses to assess its morphology and composition. Postconsumer PET bottles were shredded and processed with 20 wt% BLA and 16 equivalents of ethylene glycol (EG) at 190 °C for 3.5 h under atmospheric pressure to give recrystallized bis(2-hydroxyethyl) terephthalate (BHET) monomer in 83% yield. The catalyst can be reused for four catalytic cycles and the residual EG was recovered for subsequent catalytic reactions. Excellent activity, cost-free, environmental-friendliness and ease of preparation, handling and reusability of the catalyst with simple work-up procedure are the notable advantages of this protocol.

Asunto(s)

Etilenos , Tereftalatos Polietilenos , Biomasa , Ácidos Ftálicos , Espectroscopía Infrarroja por Transformada de Fourier

RESUMEN

Plastic production has increased by almost 200-fold annually from 2 million metric tons per year in 1950s to 359 million metric tons in 2018. With this rapidly increasing production, plastic pollution has become one of the most demanding environmental issues and tremendous efforts have been initiated by the research community for its disposal. In this present study, we reported for the first time, a biomass-waste-derived heterogeneous catalyst prepared from waste orange peel for the depolymerisation of poly(ethylene terephthalate) (PET) to its monomer, bis(2-hydroxyethyl terephthalate) (BHET). The prepared orange peel ash (OPA) catalyst was well-characterised using techniques such as IR, inductively coupled plasma (ICP)-OES (Optical Emission Spectrometry), XRD, X-ray fluorescence (XRF), SEM, energy-dispersive X-ray spectroscopy (EDX), TEM, BET (Brunauer-Emmett-Teller) and TGA. The catalyst was found to be composed of basic sites, high surface area, and a notable type-IV N2 adsorption-desorption isotherm indicating the mesoporous nature of the catalyst, which might have eventually enhanced the rate of the reaction as well as the yield of the product. The catalyst completely depolymerises PET within 90 min, producing 79% of recrystallised BHET. The ability of reusing the catalysts for 5 consecutive runs without significant depreciation in the catalytic activity and its eco- and environmental-friendliness endorses this protocol as a greener route for PET recycling.