Toughening of Bio-Based PA 6.19 by Copolymerization with PA 6.6 - Synthesis and Production of Melt-Spun Monofilaments and Knitted Fabrics

This work reports on the synthesis of statistical copolymers of bio-based PA 6.19 and PA 6.6 together with the production of melt-spun monofilaments for the production of sustainable textile fibers. The plant oil-based 1.19-nonadecanedioic acid is synthesized from bio-derived oleic acid via isomerizing methoxycarbonylation. The homopolymer PA 6.19 with a carbon-based bio-content of 72% shows a good elongation at break of 166%, but lower tensile strength than commercial PA 6 (43 MPa versus 82 MPa). Addition of adipic acid to form statistical PA 6.6/6.19 copolymers improves toughness while maintaining the high elongation at break. Two PA 6.6/6.19 copolymers with a carbon-based bio-content of 26% and 33% are successfully synthesized and exhibited comparable toughness (94  ±  6 MPa and 92  ±  2 MPa) to the commercial PA 6 (92  ±  15 MPa). The bio-based copolymers also exhibit a much lower water uptake than PA 6 and PA 6.6, resulting in a higher dimensional stability. Melt spinning of the oleic acid-based polyamides is successfully carried out to produce monofilaments with sufficient properties for further processing in a knitting process, demonstrating the capabilities of the bio-based PA 6.6/6.19 copolymers for use in the textile industry.

Toward combined photobiological-photochemical formation of kerosene-type biofuels: which small 1,3-diene photodimerizes most efficiently?

A transition from fossil- to bio-based hydrocarbon fuels is required to reduce greenhouse gas emissions; yet, traditional biomass cultivation for biofuel production competes with food production and impacts negatively on biodiversity. Recently, we reported a proof-of-principle study of a two-step photobiological-photochemical approach to kerosene biofuels in which a volatile hydrocarbon (isoprene) is produced by photosynthetic cyanobacteria, followed by its photochemical dimerization into C₁₀ hydrocarbons. Both steps can utilize solar irradiation. Here, we report the triplet state (T₁)-sensitized photodimerization of a broader set of small 1,3-dienes to identify which structural features lead to rapid photodimerization. Neat 1,3-cyclohexadiene gave the highest yield (93%) after 24 h of irradiation at 365 nm, followed by isoprene (66%). The long triplet lifetime of 1,3-cyclohexadiene, which is two orders of magnitude longer than those of acyclic dienes, is key to its high photoreactivity and stem from its planar T₁ state structure. In contrast, while isoprene is conformationally flexible, it has both photochemical and photobiological advantages, as it is the most reactive among the volatile 1,3-dienes and it can be produced by cyanobacteria. Finally, we explored the influence of solvent viscosity, diene concentration, and triplet sensitizer loading on the photodimerization, with a focus on conditions that are amenable when the dienes are produced photobiologically. Our findings should be useful for the further development of the two-step photobiological-photochemical approach to kerosene biofuels.

Olefin Metathesis in Confined Spaces: The Encapsulation of Hoveyda-Grubbs Catalyst in Peanut, Square, and Capsule Shaped Hollow Silica Gels

In this study, Hoveyda-Grubbs 2nd generation (HG2) catalyst was encapsulated in hollow mesoporous silica gels with various morphologies (peanut, square, and capsule) by reducing the pore size of the mesoporous...

Fatty Acids and their Derivatives as Renewable Platform Molecules for the Chemical Industry

Oils and fats of vegetable and animal origin remain an important renewable feedstock for the chemical industry. Their industrial use has increased during the last 10 years from 31 to 51 million tonnes annually. Remarkable achievements made in the field of oleochemistry in this timeframe are summarized herein, including the reduction of fatty esters to ethers, the selective oxidation and oxidative cleavage of C-C double bonds, the synthesis of alkyl-branched fatty compounds, the isomerizing hydroformylation and alkoxycarbonylation, and olefin metathesis. The use of oleochemicals for the synthesis of a great variety of polymeric materials has increased tremendously, too. In addition to lipases and phospholipases, other enzymes have found their way into biocatalytic oleochemistry. Important achievements have also generated new oil qualities in existing crop plants or by using microorganisms optimized by metabolic engineering.

Fully Renewable Non-Isocyanate Polyurethanes via the Lossen Rearrangement

In this work, a straightforward and efficient synthesis approach to renewable non-isocyanate polyurethanes (NIPUs) is described. For this purpose, suitable and renewable carbamate monomers, possessing two double bonds, are synthesized from hydroxamic fatty acid derivatives via the Lossen rearrangement in a one-step synthesis, and sustainable dithiols are synthesized from dialkenes derived from renewable feedstock (i.e., limonene and 1,4-cyclohexadiene). Subsequently, the comonomers are polymerized with the highly efficient thiol-ene reaction to produce NIPUs with M_n values up to 26 kg mol^-1 bearing thioether linkages. The main side product of the Lossen rearrangement, a symmetric urea, can also be polymerized in the same fashion. Important in the view of sustainability, the monomer mixture can also be used directly, without separation. The obtained polymers are characterized by NMR, attenuated total reflection-infrared spectroscopy, differential scanning calorimetry, and size exclusion chromatography.

The unrevealed potential of elemental sulfur for the synthesis of high sulfur content bio-based aliphatic polyesters

We introduce a novel sulfur-containing polyester derivative based on a renewable monomer bearing secondary disulfide groups. Base-mediated sulfur exchange reaction of disulfide bonds using S₈ delivers polyesters with tailored functional properties.

Efficient Conversion of Renewable Unsaturated Fatty Acid Methyl Esters by Cross-Metathesis with Eugenol

Cross-metathesis of unsaturated fatty acid methyl esters (methyl oleate (MO), methyl petroselinate (MP), and methyl erucate (ME), obtained from vegetable oils) with eugenol (obtained from clove oil) proceeded under green, mild conditions (in 2-propanol or ethanol at 50 °C) in the presence of a ruthenium-carbene catalyst (called a second-generation Grubbs catalyst). These metathesis reactions proceeded with both high conversion (>90% of MO, MP) and selectivity (>98%) even with low catalyst loading (0.1 mol % Ru).

Renewability is not Enough: Recent Advances in the Sustainable Synthesis of Biomass-Derived Monomers and Polymers

Taking advantage of the structural diversity of different biomass resources, recent efforts were directed towards the synthesis of renewable monomers and polymers, either for the substitution of petroleum-based resources or for the design of novel polymers. Not only the use of biomass, but also the development of sustainable chemical approaches is a crucial aspect for the production of sustainable materials. This review discusses the recent examples of chemical modifications and polymerizations of abundant biomass resources with a clear focus on the sustainability of the described processes. Topics such as synthetic methodology, catalysis, and development of new solvent systems or greener alternative reagents are addressed. The chemistry of vegetable oil derivatives, terpenes, lignin, carbohydrates, and sugar-based platform chemicals was selected to highlight the trends in the active field of a sustainable use of renewable resources.

Cross metathesis of methyl oleate (MO) with terminal, internal olefins by ruthenium catalysts: factors affecting the efficient MO conversion and the selectivity

Cross metathesis (CM) of methyl oleate (MO) with cis-4-octene, cis-stilbene, allyltrimethylsilane by RuCl₂(PCy₃)(IMesH₂)(CHPh) yielded CM products with high MO conversion, high selectivity; the effect of olefin substituents, conditions was explored.

Self-assembly of well-defined fatty acid based amphiphilic thermoresponsive random copolymers

Side-chain stearic acid containing thermoresponsive and crystalline random copolymers are synthesized via RAFT technique, which self-assembled to spherical micellar structures in aqueous solution depending on stearate content in the copolymer.

Development of a vegetable oil based plasticizer for preparing flame retardant poly(vinyl chloride) materials

A novel method was developed to prepare a castor oil based flame retardant plasticizer containing phosphaphenanthrene groups (PCOPE) for the preparation of poly(vinyl chloride) (PVC).

Effect of the biobased linear long-chain monomer on crystallization and biodegradation behaviors of poly(butylene carbonate)-based copolycarbonates

In this work, high-molecular-weight poly(butylene carbonate)-based copolycarbonates with highly enhanced crystallization property were successfully prepared, by randomly copolymerizing with a biobased linear long-chain aliphatic diol.

Promotion of selective pathways in isomerizing functionalization of plant oils by rigid framework substituents

The 1,2-(CH2 P(1-adamantyl)2 )2 C6 H4 (dadpx) coordinated palladium complex [(dadpx)Pd(OTf)2 ] (1) is a catalyst precursor for the isomerizing methoxycarbonylation of the internal double bond of methyl oleate, with an unprecedented selectivity (96 %) for the linear diester 1,19-dimethyl nonadecanedioate. Rapid formation of the catalytically active solvent-coordinated hydride species [(dadpx)PdH(MeOH)](+) (3-MeOH) is evidenced by NMR spectroscopy, and further isolation and X-ray crystal structure analysis of [(dadpx)PdH(PPh3 )](+) (3-PPh3 ). DFT calculations of key steps of the catalytic cycle unravel methanolysis as the decisive step for enhanced selectivity and the influence of the rigid adamantyl framework on this step by destabilization of transition states of unselective pathways.