Regioselective synthesis of renewable bisphenols from 2,3-pentanedione and their application as plasticizers

Abstract

Pentanedione (2,3-PD), a bio-based chemical derived from lactic acid, has the potential to serve as a precursor for the synthesis of novel bisphenols. We developed a solvent-free catalytic strategy for the condensation of phenol with 2,3-PD by using acid catalysts at temperatures ranging from 323 to 373 K.Various soluble and solid acids exhibit high activity, while a high chemoselectivity to bisphenol requires a high phenol to 2,3-PD molar ratio. Bisphenol yields as high as 84% are for instance reported in an excess of phenol in the presence of Nafion NR50. Recycling of the Nafion catalyst after washing with ethanol at room temperature is demonstrated. The regioselectivity in the bisphenol fraction is influenced by the acid strength. A clear trend is presented in which the regioselectivity towards the desired p,p'-isomers increases with increasing acid strength, showing p,p'/o,p'-isomer ratios as high as 100. A tentative mechanism is discussed based on the ionic versus non-ionic pathway. The purified 2,3-PD-derived p,p'-bisphenols are assessed as plasticizers for polyethylene terephthalate (PET), showing promising properties similar to that of the reference bisphenol A, but with a broader processing window due to the lower melting point and higher thermal stability under an inert atmosphere.

Water Tolerant and Reusable Sulfonated Hyperbranched Poly(aryleneoxindole) Acid Catalyst for Solvent‐Free Esterification

“…The titration experiment was performed in duplicate resulting in an average acid density of 5.3 mmol H + per g which is in line with the acid densities reported before for this material (3.7‐5.4 mmol per g H + ) ,,. The variation in acid density can be explained by several factors such as conducting the polymerization and sulfonation under different concentration of SO 3 in oleum and measurement on a wet or dry sample . The high acid density, higher than the 4.7 mmol H + per g for Amberlyst 15, reduces the total amount of SHBPAO catalyst necessary and thus is more appealing to apply in industry.…”

Synthesis of Lignin‐Derived Bisphenols Catalyzed by Lignosulfonic Acid in Water for Polycarbonate Synthesis

“…For example, products 1 and 2 have significantly lower melting points than BPA (134-136 vs. 158 8C), which offers potential advantages in the processing of polymeric compounds at a lower temperature upon using the lignin-derived bisphenols as plasticizers instead of BPA. [9] BPA-based polycarbonate is one of the most important materials.…”

“…[12,13] Therefore, on the one hand, efforts have been undertaken to seek green catalysts to replace traditional mineral acid catalysts, such as solid acidic catalysts [14] and acidic ionic liquids; [15] on the other hand, research has been performed to synthesize new bisphenols by using renewable feedstocks with the aim to replace BPA with new materials. [9,16] It is believed that the use of creosol to construct bisphenols not only benefits from the renewable nature of creo-sol but also from a number of synthetic and structural advantages that creosol has over simple phenol.…”

“…Polymerization of this monomer produces poly(dihydroferulic acid), which exhibits thermal properties similar to those of polyethylene terephthalate. [9] With the introduction of a vanillin moiety, a series of renewable aromatic-aliphatic copolyesters and Schiff base polymers have been synthesized.…”

Effects of o-Methoxy Groups on the Properties and Thermal Stability of Renewable High-Temperature Cyanate Ester Resins

“…Bis(4-methoxy-2-methylphenyl)methane (10) General Hydrolysis Process. To a −78°C solution of bis(methoxy) 10, 11, or 12 (15 mmol) in methylene chloride (30 mL) was added BBr 3 (2.1 mL, 21.8 mmol) dropwise.…”