Concerning Synthesis of New Biobased Polycarbonates with Curcumin in Replacement of Bisphenol A and Recycled Diphenyl Carbonate as Example of Circular Economy

Abstract

Curcumin (CM) is a natural polyphenol well-known for its antioxidant and pharmaceutical properties, that can represent a renewable alternative to bisphenol A (BPA) for the synthesis of bio-based polycarbonates (PC). In the presented strategy, preparation of the CM-based PC was coupled with chemical recycling of the fossil-based BPA polycarbonate (BPA-PC) conducting a two-steps trans-polymerization that replaces BPA monomer with CM or its tetrahydrogenated colorless product (THCM). In the first step of synthetic strategy, depolymerization of commercial BPA-PC was carried out with phenol as nucleophile, according to our previous procedure based on zinc derivatives and ionic liquids as catalysts, thus producing quantitatively diphenyl carbonate (DPC) e BPA. In the second step, DPC underwent a melt transesterification with CM or THCM monomers affording the corresponding bio-based polycarbonates, CM-PC and THCM-PC, respectively. THCM was prepared by reducing natural bis-phenol with cyclohexene as a hydrogen donor and characterized by 1H-NMR and MS techniques. Polymerization reactions were monitored by infrared spectroscopy and average molecular weights and dispersity of the two biobased polymers THCM-PC and CM-PC were determined by means of gel permeation chromatography (GPC). Optical properties of the prepared polymers were also measured.

Autohydrolysis Application on Vine Shoots and Grape Stalks to Obtain Extracts Enriched in Xylo-Oligosaccharides and Phenolic Compounds

“…The extracts deriving from the autohydrolysis treatment were analyzed by dissolving the dried extract in HPLC-grade water in a 1:33 ratio. The analyses were carried out using an LCMS-IT-TOF system (Shimadzu, Tokyo, Japan), consisting of a binary pump (NexeraXR, LC-20ADxr), autosampler (NexeraXR, SIL-20ADxr), and a detector (SPD-M20A), as described by Li et al [66] and De Leo et al [29] with some modifications.…”

“…An innovative identification and quantification method of the extracted sugars by the LCMS-IT-TOF system, not previously considered for these constituents, was used. This technique is well known to provide more detailed information on the structure of these compounds [29]. In addition, the obtained extracts were evaluated for their phenolic profile and antioxidant activity.…”

Synthesis and Characterization of Partially Biobased Aromatic (Co)polycarbonates Containing Biphenylene Units and Pendant Pentadecyl Chains

“…Over the past few decades, one of the widely researched topics in the area of polycarbonates is the development of biobased bisphenols [ 5–10 ] and rigid diols [ 11–19 ] as monomers as a step toward sustainability. [ 7,20–22 ] The notable examples of renewable resource‐based chemicals utilized for the synthesis of (partially) biobased bisphenols are lignin‐derived aromatic chemicals, [ 5,23–27 ] cashew nut shell liquid (CNSL), [ 28,29 ] curcumin, [ 30 ] carvacol, [ 31 ] levunilic acid, [ 32 ] and so on. Additionally, biobased polycarbonates exhibiting high thermal stability characteristics have been reported by copolymerization of carbon dioxide with epoxides derived from renewable resources such as limonene and menthol.…”

Imidazolium-Catalyzed Formation of Bisphenol A Polycarbonate with a Reduced Level of Branching

“…Imidazoliums as ionic liquids have a wide range of applications in synthesis and catalysis . Noteworthy of attention are their uses in the green synthesis of cyclic carbonates from carbon dioxide and epoxides. , Ionic liquids are also successfully applied in the synthesis of linear polycarbonates in recent examples. − The bio-based poly­(isosorbide carbonate) (PIC) as a green sustainable material compared to the conventional BPA-based PC, which has superior optical properties and outstanding scratch resistance, has been commercialized by Mitsubishi Chemical Corporation and Teijin as DURABIO and PLANEXT, respectively. In this contribution, we report the formation of biphenyl A polycarbonate with more than 30 imidazolium catalysts, including easily accessible commercial products and newly synthesized compounds.…”