Synthesis of dihydroxy telechelic oligomers of <scp>β‐butyrolactone</scp> catalyzed by titanium( <scp>IV</scp> )‐alkoxides and their use as macrodiols in polyurethane chemistry

Abstract We report on a solvent‐free approach for the synthesis of low molecular weight, α,ω‐dihydroxy telechelic poly(β‐butyrolactone). In presence Ti(IV) alkoxides, mixtures β‐butyrolactone and diols, like di‐ or triethylene glycol, were reacted in ratios between 4:1 10:1. The oligomerization proceeds at elevated temperatures (80–100°C). Different alkoxide substituents (R = Me, i Pr, t Bu) Ti(IV)(OR) 4 catalyst investigated. resulting oligomers characterized by nuclear magnetic resonance (NMR), infra‐red (IR), gel‐permeation chromatography (GPC), titration, matrix‐assisted laser desorption‐time‐of‐flight mass spectrometry (MALDI‐ToF‐MS) analysis. Aside from weight products, special effort was devoted to achieve high O ‐acyl cleavage selectivity circumvent formation unsaturated end‐groups order form exclusively dihydroxy‐telechelic oligomers. Optimized results terms reaction rates achieved 100°C using loadings 0.2 mol% with respect monomer. weights determined GPC good accordance ratio monomer diol used, confirming successful oligomer formation. Polyurethanes prepared crude macrodiols without any additional feature up 50,000 g/mol. reported work serves as concept utilize β‐lactones tailored polyol synthesis; products are suitable polyurethane chemistry.