Selective alkylation by zeolite catalysis opens up a sustainable platform of bisphenol substitutes from biomass.

Abstract

Sustainable bisphenol A (BPA) substitutes should be safe and renewable to abolish the environmental burden of BPA’s endocrine disruption and petrochemical origin. Suitable alternatives preferably also retain the rigid and stiff methylenediphenol (MDP) scaffold to emulate the hallmark performance of BPA-based polymers. Here, we report a holistic solution to sustainable BPA substitutes made from abundant lignin-derivable o-methoxyphenols that display low-to-undetectable xeno-estrogenic activity while preserving the MDP scaffold. More specifically, we propose an innovative zeolite-catalyzed synthesis towards the similar albeit safer methylenediguaiacol (MDG) scaffold via Brønsted acid-catalyzed alkylation of guaiacol with different p-alkenylguaiacols yielding various so-called bisguaiacols. Zeolite catalysis favors regioselectivity and prompts higher rate and chemoselectivity for entropic reasons thanks to active site pocket confinement. Exploiting the intrinsic handles present in o-methoxyphenols not only simplifies and ameliorates classic bisphenol chemistry, but also enables to design out xeno-estrogenic activity. Successful direct reaction of a crude lignin oil extract, as produced by reductive catalytic fractionation, highlights the feasibility and robustness of this route as a downstream process for future wood biorefineries. Last but not least, pure p,p’-bisguaiacols are polymerized into high-molecular weight thermoplastic and thermosetting polymers with promising thermo-physical properties. Overall, this work elucidates that renewability should not merely serve as a goal (renewable carbon), but also as a means (safer chemicals), thereby transcending the scope of renewability.

Harnessing Atomically Dispersed Cobalt for the Reductive Catalytic Fractionation of Lignocellulose

“…[6,14,41] As the RCF develops, utilizing lignin-depolymerized monomers (not model compounds or lignin-mimics) to produce designer chemicals and materials has become a reality recently. [3,20,28,34,41,[47][48][49] Because these methoxyand alkyl-adorned lignin monomers are seldom used in current chemical and material industries, the search for new routes for fabricating lignin-derivable polymers is still a motivating aspiration.…”

The Future Biorefinery: The Impact of Upscaling the Reductive Catalytic Fractionation of Lignocellulose Biomass on the Quality of the Lignin Oil, Carbohydrate Products, and Pulp

“…As shown in the open literature, without the use of a catalyst, the repolymerization will be much more prevalent, due to the inability to stabilize the lignin intermediates (Figure S12). , With RCF about 50 to 90% of the biomass lignin, depending on the feedstock and the reaction conditions, is typically removed ultimately yielding a lignin oil with unique properties such as low molecular weight (MW) (<1000 Da) with a narrow polydispersity (<1.4) and high hydroxyl selectivity, making it an interesting precursor for multiple applications. − Although lignin valorization is a key aspect to achieve full biomass utilization, the majority of the lignocellulose biomass is composed of a carbohydrate-rich fraction, remaining as a pulp after RCF, that has received increased attention in the past decades as a resource for the production of biobased chemicals. − To exploit this fraction, a complex mixture of cellulases and hemicellulases are required to obtain the C5 and C6 monomeric sugars that are present within the lignocellulose biomass and can be upgraded biochemically to, e.g., bioethanol using yeast, which has been specifically demonstrated with RCF pulp as well. ,− …”

Herbaceous plants-derived hydroxycinnamic units for constructing recyclable and controllable copolyesters

“…[34][35][36][37][38][39][40] Recent progress on the controllable depolymerization of lignin has paved the way for preparing aromatic monomers and polymers in a sustainable manner. [41][42][43][44][45] Yan illustrated that TPA could be synthesized from corn stover lignin-derived monomers through a three-step strategy. 42 Epps III and co-workers reported that side-chained syringols and guaiacols, direct products from poplar lignin hydrogenolysis, can serve as a major component for fabricating high-performance pressure-sensitive adhesives and photocurable three-dimensional (3D) printing resins.…”

“…44 Sels and co-workers reported that lignin-depolymerized monomers could be transformed into bisphenol substitutes and corresponding polymers with promising thermo-physical properties. 45 In the above-mentioned work, the polymer construction of lignin-derived monomers aimed to utilize the phenolic group, wherein the side-chains were seen as decorations. Furthermore, their polymerizing partners were produced from fossil resources.…”