Yuya Tachibana

Chemical Synthesis of Fully Biomass-Based Poly(butylene succinate) from Inedible-Biomass-Based Furfural and Evaluation of Its Biomass Carbon Ratio

We have produced fully biomass-based poly(butylene succinate) (PBS) from furfural produced from inedible agricultural cellulosic waste. Furfural was oxidized to give fumaric acid. Fumaric acid was hydrogenated under high pressure with a palladium-rhenium/carbon catalyst to give 1,4-butanediol, and with a palladium/carbon catalyst to give succinic acid. Dimethyl succinate was synthesized from fumaric acid by esterification and hydrogenation under normal pressure. Fully biomass-based PBS was obtained by polycondensation of biomass-based 1,4-butanediol and biomass-based succinic acid or dimethyl succinate. The biomass carbon ratio calculated from (14)C concentrations measured by accelerator mass spectroscopy (AMS) verified that the PBS obtained in this study contained only biomass carbon. The polycondensation of biomass-based 1,4-butanediol and petroleum-based terephthalic acid or dimethyl terephthalate gave partially biomass-based poly(butylene terephthalate), which is an engineering plastic.

Synthesis and Verification of Biobased Terephthalic Acid from Furfural

Exploiting biomass as an alternative to petrochemicals for the production of commodity plastics is vitally important if we are to become a more sustainable society. Here, we report a synthetic route for the production of terephthalic acid (TPA), the monomer of the widely used thermoplastic polymer poly(ethylene terephthalate) (PET), from the biomass-derived starting material furfural. Biobased furfural was oxidised and dehydrated to give maleic anhydride, which was further reacted with biobased furan to give its Diels-Alder (DA) adduct. The dehydration of the DA adduct gave phthalic anhydride, which was converted via phthalic acid and dipotassium phthalate to TPA. The biobased carbon content of the TPA was measured by accelerator mass spectroscopy and the TPA was found to be made of 100% biobased carbon.

Utilization of a Biodegradable Mulch Sheet Produced from Poly(Lactic Acid)/Ecoflex®/Modified Starch in Mandarin Orange Groves

We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet.

Thiazolium-Tethering Rotaxane-Catalyzed Asymmetric Benzoin Condensation: Unique Asymmetric Field Constructed by the Cooperation of Rotaxane Components

Asymmetric benzoin condensation of aromatic aldehydes with two kinds of optically active rotaxanes possessing thiazolium salt moieties was studied. A binaphthyl group as the chiral auxiliary was introduced in either the wheel or the axle component of the rotaxanes. Rate of the catalytic benzoin condensation of benzaldehyde with a rotaxane catalyst without the binaphthyl moiety was compared with its axle component to understand the effect of wheel component. Among several solvents used, methanol was the best solvent, which showed the highest yield (98%) of benzoin in the presence of 5 mol% of either the rotaxane and the axle catalysts. The benzoin condensations of aromatic aldehydes catalyzed by the chiral rotaxanes were studied in detail and found to give optically active benzoins with 0–32% e.e. in 5–92% yield depending on the structure of the rotaxane and the reaction conditions employed. From the results, two intrarotaxane chirality transfers are confirmed: (i) through-space chirality transfer from wheel to axle and (ii) through-bond chirality transfer controlled with an achiral wheel. Because these asymmetric reaction fields are specific to the rotaxane structure, the importance and possibility of the “rotaxane field” as a particular reaction field are demonstrated.

Synthesis and characterization of a renewable polyester containing oxabicyclic dicarboxylate derived from furfural

Techniques using biomass-based materials have become important to reduce the impacts of global warming and the depletion of petroleum resources. Changing biomass from edible to inedible is essential to solve global food issues. Furan derivatives are ideal chemicals for green chemistry because they are produced from inedible biomass resources. Here, we report the preparation of a biomass-based oxabicyclic dicarboxylic anhydride derived from furan derivatives and its polymerization with several α,ω-diols to polyoxabicyclates. 1H NMR spectra and MALDI-TOF MS measurements verified the chemical structure of the polyoxabicyclates. Polyoxabicyclates prepared using 1,3-propanediol or 1,4-butanediol could be moulded into elastic films by melt pressing. Tensile strength testing of the films indicated that they were highly elastic. Furthermore, the films had good transparency in the visible region.

The Use of Glycerol Carbonate in the Preparation of Highly Branched Siloxy Polymers

Glycerol is an important biomass feedstock readily available as a by-product from the production of fatty acid methyl esters (FAME). Glycerol can be converted to glycerol carbonate, which readily reacts with many nucleophilic reagents including amines. Here, we demonstrate the reaction of glycerol carbonate and 3-aminopropylalkoxylsilane to yield hydroxyl alkyl terminated silanes. This reaction follows a second order rate constant irrespective of the type of aminosilane that was used. These hydroxyl alkyl terminated silanes were further polymerized to yield highly branched siloxy polymers via self-polycondensation through exchange of the ethoxy groups attached to the silicon atom with the terminal hydroxyl groups. The biobased content of these products was determined by ASTM 6866 to be as high as 69 %. The synthesis of the silane monomers as well as the structure and key properties of the hydroxyl alkyl terminated siloxy polymers were determined by DSC, 1H NMR, FTIR, TGA and GPC.

Biobased Poly(Schiff-Base) Composed of Bifurfural

In this study, bifurfural, an inedible biobased chemical and a second-generation biomass, was polymerized with several diamines using an environmentally benign process, and the chemical structures of the resulting poly(Schiff base)s were analyzed. Because furan rings, which are only produced from biomass and not from fossil resources, endow polymers with unique properties that include high rigidity and expanded π-conjugation, bifurfural, which contains two furan rings, is of significant interest as a biobased building block. 1H NMR, IR, and matrix assisted laser desorption ionization-time of flight mass spectra of the poly(Schiff base)s reveal that they are composed of mixtures of linear and cyclic structures. The UV–vis spectroscopy and molecular orbital theory confirm the extended π-conjugation in the bifurfural/p-phenylenediamine poly(Schiff base) system. Poly(Schiff base)s composed of bifurfural and 1,3-propanediamine, 1,4-butandiamine, 1,5-pentanediamine, and 1,6-hexanediamine were molded at 120 °C into films that exhibited good strengths and were tough to bend. These results indicate that bifurfural-based poly(Schiff base)s are promising biobased materials.

Difference in environmental degradability between poly(ethylene succinate) and poly(3-hydroxybutyrate)

A chemosynthetic aliphatic polyester, poly(ethylene succinate) (PESu), was degraded by a poly(3-hydroxybutyrate) (P(3HB)) depolymerase in vitro. While P(3HB) exhibited good biodegradability in all environments, PESu hardly underwent biodegradation in a marine environment. To understand the difference in environmental degradability between PESu and P(3HB), we investigated the distribution of P(3HB)- and PESu-degrading microbes in various environments. PESu-degrading microbes were never detected in marine environments. PESu-degrading bacteria isolated from various environments in this study belonged to the phyla Firmicutes and Proteobacteria. Most PESu-degrading bacterial isolates could not degrade P(3HB), suggesting that PESu was not degraded by P(3HB) depolymerase in actual environments. In addition, all bacterial isolates that were screened for P(3HB) degrading activity from various environments in this study did not degrade PESu, suggesting that PESu does not induce P(3HB) depolymerase in their bacteria and P(3HB)-degrading bacteria are not involved in biodegradation of PESu in actual environments. Taken together, these results could be related with the low biodegradability of PESu in marine environments.

catena-Poly[[(ethanol-κO)sodium(I)]-di-μ-aqua-[(rac-2′-hydr­oxy-1,1′-binaphthyl-2-yl phosphato-κO)sodium]-tri-μ-aqua]

The asymmetric unit of the polymeric title compound, [Na2(C20H13O5P)(C2H6O)(H2O)5]n, consists of two NaI ions, one 2′-hydroxy-1,1′-binaphthyl-2-yl phosphate anion, one ethanol ligand and five water molecules of crysallization. Each NaI ion has a distorted octahedral coordination geometry. The phosphate anion coordinates to one NaI ion and the ethanol molecule coordinates to the other. The five water molecules bridge the NaI ions, forming an inorganic chain structure along the b axis. The chains are connected by O—H⋯O hydrogen bonds into an organic–inorganic hybrid layer parallel to (001).