Determination of hydroxyl groups in biorefinery resources via quantitative 31P NMR spectroscopy

The analysis of chemical structural characteristics of biorefinery product streams (such as lignin and tannin) has advanced substantially over the past decade, with traditional wet-chemical techniques being replaced or supplemented by NMR methodologies. Quantitative 31P NMR spectroscopy is a promising technique for the analysis of hydroxyl groups because of its unique characterization capability and broad potential applicability across the biorefinery research community. This protocol describes procedures for (i) the preparation/solubilization of lignin and tannin, (ii) the phosphitylation of their hydroxyl groups, (iii) NMR acquisition details, and (iv) the ensuing data analyses and means to precisely calculate the content of the different types of hydroxyl groups. Compared with traditional wet-chemical techniques, the technique of quantitative 31P NMR spectroscopy offers unique advantages in measuring hydroxyl groups in a single spectrum with high signal resolution. The method provides complete quantitative information about the hydroxyl groups with small amounts of sample (~30 mg) within a relatively short experimental time (~30-120 min)

Studies on the alcoholysis of poly(3-hydroxybutyrate) and the synthesis of PHB-b-PLA block copolymer for the preparation of PLA/PHB-b-PLA blends

[[abstract]]Molecular interactions, rheological behaviors and microstructures of 1,3:2,4-dibenzylidene-d-sorbitol (DBS)/poly(ethylene glycol) (PEG) organogel-inorganic silica hybrid materials are discussed in this study. DBS can dissolve in low-molecular-weight PEG to form organogels. The self-assembly behavior of these organogels was significantly influenced by the addition of the inorganic silica. The π interactions between the phenyl rings of DBS were not influenced by silica addition; however, the addition of silica affected the intermolecular hydrogen bonding of DBS, which interacts with PEG. The silica more likely interacted with PEG and decreased the intermolecular interactions between DBS and PEG, which resulted in an increase in the self-assembly of DBS. Therefore, the gel formation time and gel dissolution temperature increased as the amount of silica increased, as determined by dynamic rheological instruments. In addition, these organogel systems were all found to exhibit spherulite-like textures under polarized optical microscopy. The addition of silica and the increased DBS self-assembly in PEG resulted in a higher self-assembly temperature of the organogels. The higher temperature resulted in the presence of fewer nucleation sites and larger spherulite sizes in these systems. Small-angle X-ray scattering results demonstrated lamellar packing in these spherulite-like morphologies. Furthermore, the organogels with silica affected the intermolecular hydrogen bonding between DBS and PEG to facilitate the self-assembly of DBS, which resulted in increased diameter sizes of the DBS nanofibrils, as observed using scanning electron microscopy. It was observed that the silica was entrapped within these nanofibrillar networks.[[notice]]補正完

Divinylglycol, a Glycerol-Based Monomer: Valorization, Properties, and Applications

In the context of the development of bio-refineries, glycerol and its derivatives are co-products of the oleochemistry for which new valorization routes must be found. In this study, the polymerizability of divinylglycol (DVG), a symmetrical C-6 glycerol derivative which bears a vicinal diol and two vinyl functions was studied. The reactivity of the hydroxyl and vinyl functions of DVG through polycondensation and polyaddition reactions was investigated. In a first step, the synthesis of polyesters was carried out by reaction of DVG with various biosourced diesters. In a second route, DVG was polymerized through its vinyl functions by ADMET and thiol-ene addition. Finally, three-dimensional epoxy-amine networks were prepared from a series of diamines and bis-epoxidized DVG, the latter being prepared by oxidation of the DVG double bonds. These different polymerization reactions showed that DVG double bonds were more reactive than the alcohol ones and that a panel of original polymers could be obtained from this bio-sourced synthon