Biosynthesis of monomers for plastics from renewable oils

Omega-hydroxyfatty acids are excellent monomers for synthesizing a unique family of polyethylene-like biobased plastics. However, ω-hydroxyfatty acids are difficult and expensive to prepare by traditional organic synthesis, precluding their use in commodity materials. Here we report the engineering of a strain of the diploid yeast Candida tropicalis to produce commercially viable yields of ω-hydroxyfatty acids. To develop the strain we identified and eliminated 16 genes encoding 6 cytochrome P450s, 4 fatty alcohol oxidases, and 6 alcohol dehydrogenases from the C. tropicalis genome. We also show that fatty acids with different chain lengths and degrees of unsaturation can be more efficiently oxidized by expressing different P450s within this strain background. Biocatalysis using engineered C. tropicalis is thus a potentially attractive biocatalytic platform for producing commodity chemicals from renewable resources.     

Synthesis of high-performance green nanocomposites from renewable natural oils

This paper describes preparation and properties of green nanocomposites from renewable resources. The nanocomposites were synthesized by an acid-catalyzed curing of epoxidized natural oils in the presence of silane coupling agents. The resulting nanocomposites were transparent and highly glossy. Their hardness and Young's modulus of the nanocomposite coatings improved, as compared with those only from the epoxidized natural oils. Dynamic viscoelasticity analysis and TEM observation showed the homogeneous structure of the nanocomposites. The properties of the nanocomposites were strongly affected by the structure and feed ratio of the monomers.     

Organic-inorganic hybrids constructed by Anderson-type polyoxoanions and copper coordination complexes

Four organic-inorganic hybrid compounds based on Anderson-type polyoxoanions, namely, {[Cu(2,2′-bpy)(H₂O)₃]₂[Cr(OH)₆Mo₆O₁₈]}{[Cu(2,2′-bpy)(H₂O)Cl][Cu(2,2′-bpy)(H₂O)(NO₃)][Cr(OH)₆Mo₆O₁₈]}·18H₂O (1), [Cu(2,2′-bpy)(H₂O)₂Cl]{[Cu(2,2′-bpy)(H₂O)₂][Cr(OH)₆Mo₆O₁₈]}·4H₂O (2), (H₃O){[Cu(2,2′-bpy)(H₂O)₂]₂[Cu(2,2′-bpy)(H₂O)]₂}[Cr(OH)₆Mo₆O₁₈]₃·36H₂O (3), and (H₃O){[Cu(2,2′-bpy)(H₂O)₂]₂[Cu(2,2′-bpy)(H₂O)]₂}[Al(OH)₆Mo₆O₁₈]₃·33H₂O (4), were isolated by conventional solution method, and crystal structures have been determined by single-crystal X-ray diffraction. Among them, compound 1 displays a discrete supramolecular structure, compound 2 shows a chainlike structure with chloro-copper complexes as counteranions, and compounds 3 and 4 are isomorphic and exhibit unique 3D open frameworks with lattice water molecules residing in the channels. The compounds 3 and 4 represent the first example of 3D organic-inorganic hybrid compounds in the TMs/2,2′-bpy/POMs system. Investigation of the reaction conditions reveals that the geometry and size of the anions together with its coordinating abilities to the metal centers have a decisive influence on both the composition and the dimensionality of the final compounds.     

Organic-inorganic hybrids constructed of anderson-type polyoxoanions and oxalato-bridged dinuclear copper complexes

Two novel organic-inorganic hybrid compounds based on Anderson-type polyoxoanions, [Cu2(bpy)2(mu-ox)][Al(OH)7Mo6O17] (1) and [Cu2(bpy)2(mu-ox)][Cr(OH)7Mo6O17] (2), have been synthesized and characterized by elemental analyses, IR, and X-ray powder diffraction. The crystal structures of 1 and 2 have been established by single-crystal X-ray diffraction, which reveals the presence of 1D chains constructed of alternating Anderson-type polyoxoanions and oxalato-bridged dinuclear copper complexes for both compounds and extensive hydrogen bonding that plays an important role in the formation of the 3D supramolecular network structures of 1 and 2. To elucidate the electronic properties and magnetic properties of the metal ions (Cu2+ or Cu2+ and Cr3+), EPR studies and magnetic susceptibility studies have been performed, respectively. The results are consistent with the structural feature of these compounds.     

Processing of polypropylene - clay hybrids

Polypropylene compounds containing organophilic layered silicates were prepared by means of melt extrusion at 180°C. We have studied the effect of the coupling agent on morphology development and mechanical properties. We are convinced of the importance of both the chemistry and the process conditions to elaborate nanocomposites with optimized properties.     

Organic-inorganic nanotube hybrids: Organosilica-nanotubes containing ethane, ethylene and acetylene groups

The synthesis and characterization of novel organic-inorganic hybrid nanotubes containing silica and ethane (EtSNT), ethylene (ESNT) and acetylene (ASNT) units are presented. The unsaturated hydrocarbon linkers can be applied for a chemical functionalization of the surface of the silica nanotubes, e.g. for the grafting of organic/inorganic or organometallic molecules. These new materials are synthesized via a template method using V₃O₇·H₂O fibers and characterized by solid state MAS-NMR, FT-IR, TEM and elementary analysis. In a first approach to potential applications of these materials, the grafting of glycine on ESNT by treatment of the CC groups with Br₂ and subsequent substitution by glycine is investigated. The resulting material is characterized by solid state MAS-NMR, FT-IR, XRD, TGA, BET adsorption measurements and elementary analysis.     

Organic-inorganic hybrids in the system ruthenium tris(diimine) complexes-silica

Organic-inorganic composites in which ruthenium(II) complexes are covalently bound to the silicate matrix were prepared by the sol-gel method. The physicomechanical and optical properties of the monolithic samples obtained were studied.     

Monomers and polymers from plant oils via click chemistry reactions

As a consequence of the depleting of fossil reserves and environmental issues, today, plant oils and fatty acids derived therefrom have a respectable status within the polymer chemistry community. However, maximizing the benefits of these renewable feedstocks requires the utilization of sustainable and efficient chemical transformations. The emergence of click chemistry concept and especially the renaissance of thiol‐ene addition reaction have had an impact on the way to make plant oil‐derived polymers. This highlight discusses the applicability and success of thiol‐ene addition and other click reactions in the transformation of oleochemicals into monomers and polymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013     

The discovery of polymer‐clay hybrids

The first successful example of a polymer‐clay hybrid was nylon‐clay hybrid (NCH), which is a nano‐meter‐sized composite of nylon‐6 and 1‐nm‐thick exfoliated aluminosilicate layers of the clay mineral. NCH was found and developed at Toyota Central Research and Development Laboratories over 17 years ago. The NCH containing a few weight percentages of clay exhibits superior properties such as high modulus, high strength, and good gas‐barrier properties. The key for the discovery of NCH was the polymerization of a nylon monomer in the interlayer space of the clay. This highlight presents the development of NCH from its discovery to its commercialization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 819–824, 2004     

Bio‐based nanocomposites from functionalized plant oils and layered silicate

Some discovery work was done on the synthesis of clay nanocomposites based on renewable plant oils. Functionalized triglycerides, such as acrylated epoxidized soybean oil, maleinized acrylated epoxidized soybean oil, and soybean oil pentaerythritol maleates, combined with styrene were used as the polymer matrix. The miscibility of these monomers and clay organomodifier was assessed by solubility parameters. The formation of nanocomposites was confirmed by both X‐ray data and transmission electron microscopy. The morphology showed a mix of intercalated and partially exfoliated sheets. The flexural modulus increased 30% at only 4 vol % clay content, but there was no significant effect on flexural strength, glass‐transition temperature, and thermal stability. Property enhancement was related to the degree of exfoliation that depends on both the polarity and flexibility of the monomers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1441–1450, 2004     

Organic-inorganic hybrids assembled by bis(undecatungstophosphate) lanthanates and dinuclear copper(II)-oxalate complexes

A series of organic-inorganic hybrid compounds, K2H7[{Ln(PW11O39)2}{Cu2(bpy)2(mu-ox)}].xH2O (Ln = La, x approximately = 18 (1); Ln = Pr, x approximately = 18(2); Ln = Eu, x approximately = 16(3); Ln = Gd, x approximately 22(4); Ln = Yb, x approximately = 19 (5); bpy = 2,2'-bipyridine and ox = oxalate), have been isolated by the conventional solution method. Single-crystal X-ray diffraction studies reveal that compounds 1-5 are isomorphic and consist of one-dimensional chains, which are constructed by alternating bis(undecatungstophosphate) lanthanates [Ln(PW11O39)2](11-) and dinuclear copper(II)-oxalate complexes [Cu2(bpy)2(mu-ox)]2+.pi-pi interactions of the bpy ligands from adjacent chains lead to their three-dimensional structures. An analogue of potassium K2H9[{K(PW11O39)2}{Cu2(bpy)2(mu-ox)}1].approximately 20.5H2O(6) has also been obtained. The syntheses and structures of these compounds are reported here. Magnetic properties of 1, 2 and 3 are discussed as well. Attempts to crystallize similar compounds containing Co(II) and Ni(II) were unsuccessful.     

Volatile oils from the plant and hairy root cultures of Ageratum conyzoides L

Two lines of hairy root culture of Ageratum conyzoides L. induced by Agrobacterium rhizogenes ATCC 15834 were established under either complete darkness or 16 h light/8 h dark photoperiod conditions. The volatile oil yields from aerial parts and roots of the parent plant, the hairy root culture photoperiod line and the hairy root culture dark line were 0.2%, 0.08%, 0.03% and 0.02%, (w/w), respectively. The compositions of the volatiles from the hairy roots, plant roots and aerial parts were analysed by GC and GC-MS. The main components of the volatiles from the hairy root cultures were β-farnesene, precocene I and β-caryophyllene, in different amounts, depending on light conditions and also on the age of cultures. Precocene I, β-farnesene, precocene II and β-caryophyllene were the main constituents of the volatile oils from the parent plant roots, whereas precocene I, germacrene D, β-caryophyllene and precocene II were the main constituents of the aerial parts of the parent plant. Growth and time-course studies of volatile constituents of the two hairy root lines were compared. Qualitative and quantitative differences were found between the volatile oils from the roots of the parent plant and those from the hairy roots.     

Biosynthesis and biodegradability of copolythioesters from 3,3'-thiodipropionic acid and plant oils by Cupriviadus necator

To prepare sulfur-containing natural polymers effectively, several plant oils and 3,3'-thiodipropionic acid (TDP) have been used as carbon sources for the biosynthesis of copolymer poly[(3-hydroxybutyrate)-co-(3-mercaptopropionate)] [poly(3HB-co-3MP)] by a wild-type bacterium Cupriviadus necator H16. By using the plant oils, copolymer accumulation and incorporation of 3MP units are greater than those of cases using sugars. The 3MP fraction is controllable over a range of 1-39 mol-% by adjusting the cultivation conditions. Microbial degradability of the copolymers has been examined in an activated sludge supernatant. The biodegradation proceeded by two mechanisms: surface erosion and auto-catalytic hydrolysis, depending on the 3MP unit fraction, and show preferential degradation of 3HB unit sequences.     

Organic-inorganic telechelic molecules: solution properties from simulations

We report molecular dynamics simulations for telechelic molecules composed of two polyhedral oligomeric silsesquioxane (POSS) cages connected by one hydrocarbon backbone dissolved in liquid normal hexane. Silsesquioxanes are novel hybrid organic-inorganic molecules that are useful as building blocks for the synthesis of nanostructured materials. By including POSS molecules within a polymeric material it is possible to modify mechanical properties such as resistance to heat and glass transition temperatures. Unfortunately, the molecular mechanisms responsible for these enhancements are at present not completely understood. In an effort to elucidate the molecular phenomena responsible for these effects, we have studied the conformation of telechelic POSS molecules in solution, as well as their self-diffusion coefficients, as a function of the length of the hydrocarbon backbone. We focus on molecules in which the radius of gyration of the alkane backbone is comparable to the size of the silsesquioxane cages. Our results indicate that the backbone has a significant influence on both the equilibrium and the transport properties of dissolved telechelic hybrid molecules. These observations are useful for developing strategies to direct the self-assembly of nanostructured materials.     

Quantitation of triacylglycerols from plant oils using charged aerosol detection with gradient compensation

Quantitative analysis of triacylglycerols (TGs) in plant oils and animal fats by normalization of peak areas can lead to erroneous results due to the large response differences with common HPLC detectors between the various TGs. The charged aerosol detector (CAD), that generates an almost universal response for non-volatile compounds, was combined with non-aqueous reversed-phase HPLC (NARP-HPLC) to develop a simple quantitative method, without need for RFs, for the analysis of complex natural TG mixtures from plant oils. Two 25 cm Hypersil ODS columns, connected in series, and a mobile phase gradient composed of acetonitrile, 2-propanol and hexane were used. Mobile phase compensation was applied, by mixing of the column effluent with the inversed gradient delivered by a second HPLC pump, for the suppression of the response dependency of the analytes on the mobile phase composition. Calibration curves of 16 saturated (from C7:0 to C22:0) and 3 unsaturated (C18:1, C18:2, C18:3) single-acid TG standards were measured and their RFs were compared with a previously described method using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS). The variation in response of the most common TGs (containing fatty acid chains from 12 to 19 carbons) could be reduced to less than 5% making the combination of NARP-HPLC with CAD and mobile phase compensation an adequate tool for fast quantitative analysis of TGs in common plant oils.     

Analysis of essential oils by direct sampling from plant secretory structures and capillary gas chromatography

It is of fundamental importance to know the true composition of the essential oil produced by the secretory structures of a plant, both from a biogenetic and a chemotaxonomic point of view. This paper considers a method which combines direct sampling with on-column CGC and studies the oils directly from the secretory structures: some examples are given (Humulus lupulus L., Tagetes erecta L., and Tagetes patula L.). For each plant, the composition of the distilled oil is compared to that obtained by direct sampling, and a photograph of the secretory structures taken by electroscanning microscopy is given.     

Technique for production of oil sorbents from renewable plant raw materials: Waste from cereal plants and sphagnum moss species

Technique for production of powder sorbents from renewable plant raw materials, wastes from cereal plants and sphagnum moss species, were considered. Their sorption properties with respect to dissolved and emulsified oil products were studied.     

Thermal stability studies of some cerrado plant oils

Thermogravimetry technique is useful to determine the thermal stability of vegetable oils. In this paper some vegetable oils obtained from brazilian Cerrado native plants were studied based on their high oleic acid content. Amburana, baru and pequi pulp oils presented higher yield of extraction compared to soybean oil. The thermal stability of oils in nitrogen was very close hence their fatty acid composition was very similar. Amburana and baru oils have major amount of unsaturated fatty acids, especially linoleic acid and pequi pulp oil has the highest short chain fatty acid content which can explain its lowest thermal stability in synthetic air.     

Polybenzoxazines from renewable diphenolic acid

The novel benzoxazine monomers, DPA‐Bz and MDP‐Bz from renewable diphenolic acid (DPA), which mimics the structure of bisphenol A (BPA), were synthesized by traditional approaches. The structure and purity of the monomers was confirmed by FTIR, ¹H NMR, and ¹³C NMR spectra. The thermally activated polymerization of the MDP‐Bz and DPA‐Bz afforded thermosetting polybenzoxazines with higher T_g's, 270 °C and 208 °C respectively, and higher crosslinking density compared to BPA‐Bz, due to the transesterification or esterification reactions occurred during curing process. These reactions are in accordance with the number of independent reactions determined analyzing by SVD the chemical rank of the IR spectra data matrices recorded along the homopolymerization reactions monitored at 200 °C. Spectral and concentration profiles of the active chemical species involved in these processes were obtained by MCR‐ALS. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011