Catalyst-free valorization of poly-3-hydroxybutyrate to crotonic acid

Kang, Shimin; Chen, Rujie; Fu, Jinxia; Liang, Jianhao; Chen, Suxia; Lu, Lijun; Miao, Rongrong

doi:10.1039/d1re00273b

Cited by 11 publications

(9 citation statements)

References 12 publications

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“…The selective pyrolysis of P3HB to trans-crotonic acid (CA) was well studied. 40,43,44 Here, we adopted the reported method by using MgO as the catalyst. 43 The 1 H NMR spectrum confirms the high purity of resultant trans-CA despite the presence of less than 3% cis-structure (Figure S1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Chemical Upcycling of Poly(3-hydroxybutyrate) (P3HB) toward Functional Poly(amine-alt-ester) via Tandem Degradation and Ring-Opening Polymerization

Zhao

Huang

et al. 2022

Macromolecules

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The upcycling of plastic waste into value-added products is a promising strategy to reduce plastic pollution and create a sustainable style for polymeric materials. We report here the synthesis of a novel N-heterocyclic lactone, 5-methyl-N-Boc-1,4-oxazepane-7-one (MeOxPBoc) and corresponding poly(amine-alt-ester) through upcycling of the poly(3-hydroxybutyrate) (P3HB) biopolymer. Specifically, tens of grams of MeOxPBoc can be easily prepared from P3HB waste in a satisfactory yield. Well-controlled ring-opening polymerization (ROP) of MeOxPBoc was achieved to give an amorphous poly(amine-alt-ester) P(MeOxPBoc) with a targeted molecular weight, narrow molecular weight dispersity, and well-defined terminal groups in toluene using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst. The obtained P(MeOxPBoc) could be depolymerized back to its pristine monomer either in trimethylbenzene at 120 °C using Sn(Oct)2 as a catalyst or in bulk at 150 °C in the presence of ZnCl2 as the catalyst. After simple purification by recrystallization, the recycled MeOxPBoc could be repolymerized to produce virgin-quality polymers. Remarkably, the obtained P(MeOxPBoc) can be converted to the corresponding cationic polymer by simply removing the pendent t-butoxycarbonyl protecting group. This study provides a new insight to address the end-of-use problem of plastic by upcycling the plastic waste to value-added functional poly(amine-alt-ester) with a closed-loop life cycle.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Chemical Upcycling of Poly(3-hydroxybutyrate) (P3HB) toward Functional Poly(amine-alt-ester) via Tandem Degradation and Ring-Opening Polymerization

Zhao

Huang

et al. 2022

Macromolecules

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“…Kang et al developed a one-pot catalyst-free reaction system in cyclohexane solvent and achieved high CA yield (89 wt%) and purity (91%) at 210°C after vacuum distillation at 60°C. 24 The thermolytic distillation process was also developed by Parodi et al for PHB depolymerization and CA recoveries of 94, 78, and 58% were achieved at 170°C under 150 mbar for pure PHB and PHB-enriched bacteria containing 60 and 30% PHB, respectively. 25,26 The prepared CA can also be converted to a series of γ-keto acids via photocatalysis.…”

Section: Camentioning

confidence: 99%

“…Kang et al . developed a one‐pot catalyst‐free reaction system in cyclohexane solvent and achieved high CA yield (89 wt%) and purity (91%) at 210°C after vacuum distillation at 60°C 24 . The thermolytic distillation process was also developed by Parodi et al .…”

Section: Camentioning

confidence: 99%

Tailored recycling chemicals and fuels from poly‐3‐hydroxybutyrate: A review

Kang

Liang

Yuan

et al. 2022

Biofuels Bioprod Bioref

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With the threat of ‘white pollution’, the large‐scale production and application of biodegradable plastics have become crucial. Poly‐3‐hydroxybutyrate (PHB) is the simplest and most used member of the polyhydroxyalkanoate family, with a uniform C4 structural unit (C4H6O2). To reduce the impact of PHB on waste treatment, various recycling strategies have been developed for the tailored conversion of PHB to targeted chemicals and fuels. Given the special structural unit, PHB and its plastic forms have the potential to serve as a sustainable feedstock for producing a series of value‐added chemicals and fuels, including (i) crotonic acid via pyrolysis, (ii) (R)‐β‐hydroxybutyric acid via hydrolysis, (iii) propylene via depolymerization and decarboxylation, (iv) liquid fuels via deoxygenation and oligomerization, (v) n‐biobutanol via catalytic hydrogenolysis, (vi) methyl crotonate via thermolysis and esterification, (vii) (R)‐3‐hydroxybutyrate methyl ester via catalytic methanolysis, and (viii) β‐aminobutyric acid via ammonolysis. This review article provides a systematic review focusing on the reaction pathways, primary applications and market potential of the target products, and the pros and cons of current bio‐refineries in comparison with conventional petroleum refineries. The thermochemical processes developed for PHB degradation and polypropylene (a typical petroleum‐derived plastic to be replaced by PHB) are also comprehensively evaluated to reveal the future opportunities and challenges of PHB's broad‐scale production and utilization. PHB‐derived chemicals and fuels have a mature market already, and it is confirmed that the tailored valorization of PHB is a promising pathway to expand the market and gain more environmental and energy benefits. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

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“…The yield of CA produced through pyrolysis of PHB/PHB-enriched biomass at 310 °C is reported to be about 63%, which is 30% higher than the yield obtained by the conventional petroleum-based route. ,, Moreover, the biobased CA yield can be increased to about 80% using a catalyst or pretreatment technique . Solvent-based pyrolysis of the commercial PHB can increase the CA yield even further. , Thermal decomposition of the PHB in cyclohexane solvent at 210 °C and 5 h, followed by solvent separation by distillation, resulted in 89% CA yield with a purity of 91% . Ionic-liquid-based media was also examined as a green solvent and catalyst to obtain CA from PHB .…”

Section: Introductionmentioning

confidence: 99%

“…20 Solvent-based pyrolysis of the commercial PHB can increase the CA yield even further. 21,22 Thermal decomposition of the PHB in cyclohexane solvent at 210 °C and 5 h, followed by solvent separation by distillation, resulted in 89% CA yield with a purity of 91%. 22 Ionic-liquidbased media was also examined as a green solvent and catalyst to obtain CA from PHB.…”

Section: ■ Introductionmentioning

confidence: 99%

Crotonic Acid Production by Pyrolysis and Vapor Fractionation of Mixed Microbial Culture-Based Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Elhami

Hempenius

Schuur

2023

Ind. Eng. Chem. Res.

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Crotonic acid (CA) and trans-2-pentenoic acid (2-PA) can be obtained from renewable resources by pyrolysis of the bio-based poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer. In this study, direct pyrolysis of the PHBV-enriched biomass into CA and 2-PA was studied under an inert atmosphere and N2 carrier gas flow, aiming at obtaining high acid yields from mixed microbial cultures (MMCs). The highest yields of 80 ± 2% for CA and 67 ± 1% for 2-PA were obtained at conditions of 240 °C, 1 h, and 0.15 L/min nitrogen flow rate, corresponding to a mean hot vapor residence time of 20 s. A similar acid yield was achieved when the pyrolysis was performed under reduced pressure (150 mbar) instead of using nitrogen gas. The combined pyrolysis of extracted PHBV at 220 °C and 90 min with vapor fractionation by distillation resulted in yields of 81 and 92% for CA and 2-PA, respectively.

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Catalyst-free valorization of poly-3-hydroxybutyrate to crotonic acid

Abstract: A novel catalyst-free pyrolysis process of poly-3-hydroxybutyrate (PHB) to crotonic acid (CA) in inert nonpolar solvents was developed. After a simple consecutive process of reaction (210 oC for 5 h...

Cited by 11 publications

References 12 publications

Chemical Upcycling of Poly(3-hydroxybutyrate) (P3HB) toward Functional Poly(amine-alt-ester) via Tandem Degradation and Ring-Opening Polymerization

Chemical Upcycling of Poly(3-hydroxybutyrate) (P3HB) toward Functional Poly(amine-alt-ester) via Tandem Degradation and Ring-Opening Polymerization

Tailored recycling chemicals and fuels from poly‐3‐hydroxybutyrate: A review

Crotonic Acid Production by Pyrolysis and Vapor Fractionation of Mixed Microbial Culture-Based Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

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