The synthesis of glycerol 1,2-carbonate (GC) by transesterification of glycerol with dimethyl carbonate (DMC) using triethylamine (TEA) as a facile separable homogeneous catalyst has been studied at different temperatures, DMC/glycerol molar ratios and TEA/glycerol molar ratios. Reaction rate increases dramatically with temperature and TEA/glycerol molar ratio but the reaction is difficult to stop in the target molecule at the highest TEA/glycerol molar ratios because GC undergoes further transesterification to glycerol dicarbonate (GDC). However, good reaction control can be achieved by working at a TEA/glycerol molar ratio of 0.1: a 99% glycerol conversion and a 98% GC yield are obtained in 2.5 h with a DMC/glycerol molar ratio of 4 at refluxing temperature (88 °C → 68 °C). At 90 °C glycidol is also formed in 6–10% yields. A mechanism to justify its synthesis is proposed. GDC formation can be avoided at conversions below 100% but in this case GC is highly impurified with glycerol after solvent removal by evaporation. To separate both chemicals a liquid–liquid extraction method has been developed. Selective extraction solvents for GC, such as methyl isobutyl ketone (MIBK) or DMC, were found using the method of miscibility numbers. GC is selectively extracted at room temperature in MIBK in a 100% yield with purity higher than 98% from a glycerol–GC mixture consisting of 80 wt% GC by using a MIBK/mixture mass ratio of 1.6 and three extraction steps.

A family of lignin-based polyols (LBPs) has been prepared and characterized using a novel and unprecedented synthetic approach consisting of a cationic ring opening polymerization reaction of oxiranes in the presence of tetrahydrofuran as both the solvent and co-monomer and an organosolv lignin (OL) at atmospheric pressure and room temperature in acidic media. This new route avoids the drawbacks of the current base-catalyzed lignin oxypropylation method used to obtain LBPs, such as the formation of a large amount of side products, the harsh reaction conditions (high temperatures (>150 °C) and pressure) resulting in lignin fragmentation and the generation of phenolic moieties that produce an unpleasant odour limiting the fields of application of LBPs. To demonstrate the versatility of the novel proposed synthetic route, several LBPs were obtained using butylene oxide, propylene oxide, glycidol and epichlorohydrin as oxiranes. The characterization of the obtained LBPs was performed by means of gel permeation chromatography (GPC), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and attenuated total reflection-Fourier transform infrared (ATR-FTIR), as well as determination of the hydroxyl number. LBPs with a lignin content from 11.3 to 30.1 wt%, and weight average molecular weights from 2730 to 30 258 g mol⁻¹, and hydroxyl values from 53 to 253 mg KOH per g were obtained. Furthermore, the reactivity of these LBPs with diisocyanates was evidenced and a plausible reaction mechanism is proposed. This novel developed method is of potential industrial interest, mainly in the field of the pulp industry, of which the major byproduct is lignin, as well as in the bio-polyol and bio-polymer industries.

Isosorbide bis(methyl carbonate) (IBMC) is a scarcely studied green chemical with potential applications in the manufacturing of non-isocyanate polyurethanes and bisphenol A-free polycarbonates. Its synthesis by transesterification of isosorbide with dimethyl carbonate (DMC) is very negatively influenced by the presence of small amounts of acidic impurities in isosorbide when heterogeneous inorganic carbonates such as potassium and cesium carbonates are used as catalysts. In this paper it is shown that the problem can be solved by using homogeneous catalysts consisting of nitrogenated bases and superbases having a suitable dual nucleophilic–basic character and able to form a highly reactive acyl intermediate with the electrophilic reactant DMC. Cycloaliphatic secondary and tertiary amines, guanidines and amidines covering a nucleophilicity parameter (N) range between 13.58 and 20.58 in either acetonitrile or dichloromethane, and a pK_a range in acetonitrile between 15.68 and 26.02 have been tested in batchwise mode. Highly active catalysts leading to hydroxyl conversions of 84–93% require a minimum N of 16 and a pK_a ranging from 18.0 to 26.0. Within this pK_a range, N must increase by about 0.5–0.6 units per each unit the pK_a falls to keep the catalytic activity, indicating that nucleophilicity has approximately twice as much influence as basicity on the catalytic activity. One guanidine (TBD), one amidine (DBN) and three cycloaliphatic secondary amines (N-methylpyrrolidine, quinuclidine and DABCO) have been found to be excellent catalysts at 5 mol% vs. ISO. The side reaction leading to oligomer formation is not avoided, with oligomers, mainly the dimer, affording 6 wt% of the crude product independently of hydroxyl-conversion and catalyst type.