Recyclable Polycarbosilane from a Biomass-Derived Bifuran-Based Monomer.

Two of the most fundamental principles for the development of next-generation polymers are production from renewable biomass and well-designed recyclability. Bifuran derivatives represent promising building blocks for functional polymers on account of their high rigidity, strong interchain interactions, and extended π-conjugation. In this study, a polycarbosilane containing a bifuran-based repeat unit was prepared via the hydrosilylation of dihydrosilylbifuran and 1,5-hexadiene.

Environmental biodegradability of recombinant structural protein.

Next generation polymers needs to be produced from renewable sources and to be converted into inorganic compounds in the natural environment at the end of life. Recombinant structural protein is a promising alternative to conventional engineering plastics due to its good thermal and mechanical properties, its production from biomass, and its potential for biodegradability. Herein, we measured the thermal and mechanical properties of the recombinant structural protein BP1 and evaluated its biodegradability.

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. H 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.

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.

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.

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((R)) 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.

catena-Poly[[(ethanol-κO)sodium(I)]-di-μ-aqua-[(rac-2'-hydr-oxy-1,1'-binaphthyl-2-yl phosphato-κO)sodium]-tri-μ-aqua].

The asymmetric unit of the polymeric title compound, [Na(2)(C(20)H(13)O(5)P)(C(2)H(6)O)(H(2)O)(5)](n), consists of two Na(I) ions, one 2'-hydr-oxy-1,1'-binaphthyl-2-yl phosphate anion, one ethanol ligand and five water molecules of crysallization. Each Na(I) ion has a distorted octa-hedral coordination geometry. The phosphate anion coordinates to one Na(I) ion and the ethanol mol-ecule coordinates to the other.

Sequential O- and N-acylation protocol for high-yield preparation and modification of rotaxanes: synthesis, functionalization, structure, and intercomponent interaction of rotaxanes.

A pseudorotaxane consisting of a 24-membered crown ether and secondary ammonium salt with the hydroxy group at the terminus was quantitatively acylated by bulky acid anhydride in the presence of tributylphosphane as catalyst to afford the corresponding rotaxane in high yield. Large-scale synthesis without chromatographic separation was easily achieved. The ammonium group in the resulting rotaxane was quantitatively acylated with excess electrophile in the presence of excess trialkylamine.

Is the tert-butyl group bulky enough to end-cap a pseudorotaxane with a 24-crown-8-ether wheel?

Although rotaxane chemists have long believed that the tert-butyl group is bulkier than the cavity of dibenzo-24-crown-8-ether (DB24C8), it is essentially smaller than the cavity of DB24C8. The tert-butyl (or 4-tert-butylphenyl) group can actually function as an end-cap of DB24C8-based rotaxanes when the intercomponent interaction is effectively operative. When such attractive interaction is removed, deslippage occurs.

Asymmetric benzoin condensation catalyzed by chiral rotaxanes tethering a thiazolium salt moiety via the cooperation of the component: can rotaxane be an effective reaction field?

Although some reactions on rotaxanes have been reported, the characteristic features of the rotaxanes providing unique reaction fields have hardly been studied, especially as catalyst. In our continuous studies on interlocked molecules such as rotaxanes and catenanes, we have noticed the importance of such interlocked structures with high freedom in functionalized materials such as molecular catalyst. For catalytic asymmetric benzoin condensations, two optically active rotaxanes possessing thiazolium salt moieties were prepared using the binaphthyl group as the chiral auxiliary.