Synthesis of levulinic acid–glycerol ketal–ester oligomers and structural characterization using NMR spectroscopy

Fully Bio-based Poly(ketal-ester)s by Ring-opening Polymerization of a Bicylcic Lactone from Glycerol and Levulinic Acid

A fully renewable bio-based bicyclic lactone containing a five-membered cyclic ketal moiety, 7-methyl-3,8,10-trioxabicyclo[5.2.1]decan-4-one (TOD), was synthesized through a two-step acid-catalyzed process from glycerol and levulinic acid. The ring-opening polymerization (ROP) of TOD at 30°C with benzyl alcohol (BnOH) as the initiator and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the catalyst can afford high molar mass PTOD with a cis-2.4-disubstitued 2-methyl 1,3-dioxolane moiety in its repeating unit. PTOD is an amorphous polymer with a glass transition temperature (T_g ) of 13°C. It can be hydrolyzed into structurally defined small molecules under acidic or basic conditions by the selective cleavage of either the cyclic ketal or the ester linkage respectively. The TBD-catalyzed copolymerization of L-lactide (L-LA) and TOD at -20°C was investigated. It was confirmed that L-LA polymerized quickly with racemization to form PLA, followed by a slow incorporation of TOD into the formed PLA chains via transesterification. By varying the feed ratios of L-LA to TOD, a series of random copolymers (PLA-co-PTOD) with different TOD incorporation ratios and tunable T_g s were obtained. Under acidic conditions, PLA-co-PTOD degrades much faster than PLA via the selective cleavage of the cyclic ketal linkages. This work provides insights for the development of more sustainable and acid-accelerated degradable alternatives to aliphatic polyesters.

Levulinic acid: a sustainable platform chemical for novel polymer architectures

Levulinic acid is a multipurpose platform chemical that is currently used in a wide variety of applications.

Reductive Amination/Cyclization of Methyl Levulinate with Aspartic Acid: Towards Renewable Polyesters with a Pendant Lactam Unit

Environmental regulation and depletion of fossil resources are boosting the search for new polymeric materials produced from biomass. Here, the synthesis of a new diester bearing a pendant lactam unit from methyl levulinate and aspartic acid is reported. The palladium-catalyzed reductive amination/cyclization sequence was carefully optimized to afford the diacid with high yield (>95 %). In a second step, the compound was esterified to give the corresponding diester. The latter monomer was copolymerized with α-ω linear diols, yielding polyesters with molecular weights up to 20.5 kg mol^-1 .

Thermoplastic polyacetals: chemistry from the past for a sustainable future?

This review serves as a guide to the synthesis and applications of thermoplastic polyacetals, highlighting in particular sustainability and degradability aspects.

Sulfuric acid and Amberlyst-H+ catalyzed condensation reactions of renewable keto acids with paraformaldehyde: synthesis of a new dispiro bis-lactone ring system 2,9,13-trioxadispiro[4.1.4.3]tetradecane-3,6,10-trione

The acid catalyzed condensation of levulinic acid with paraformaldehyde at 80 °C gives 2,9,11,14-tetraoxadispiro[4.1.5.3]pentadecane-3,6-dione, in which the structure was confirmed by X-ray crystallography.

Mesoporous Zr–SBA-16 catalysts for glycerol valorization processes: towards biorenewable formulations

Zr-containing SBA-16 materials were utilized in glycerol valorization for the production of esters (via reaction with levulinic acid) and glycerol formal (GF) via acetalisation with paraformaldehyde.

(Co)Polymerization of vinyl levulinate by cobalt-mediated radical polymerization and functionalization by ketoxime click chemistry

(Co)polymerization of vinyl levulinate (with vinyl acetate) by cobalt-mediated radical polymerization affords well-defined poly(vinyl ester)s. Pendant ketone functionalities are conjugated by ketoxime click chemistry.

Synthesis and Characterization of All Renewable Resources Based Branched Polyester: Poly(2,5-furandicarboxylic acid-co-glycerol)

Condensation of all renewable resources based monomers 2,5-furandicarboxylic acid and glycerol in the presence of 2 mol% Sb2O3 catalyst at 210°C gives a branched polyester resin in 70% yield. This resin was characterized by elemental analysis, 1H, 13C NMR, FT-IR, and TGA-DTG.