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

Bio-based 1,5-Pentanediol as a Replacement for Petroleum-Derived 1,6-Hexanediol for Polyester Polyols, Coatings, and Adhesives

“…In addition to these polyester structures, peak E may represent monohydroxylic oligomers that came from the initiation of DVL by TBT (Scheme ). Similar results were also observed in a previous study where minor amounts of monohydroxylic polymers were generated from the initiation of β-butyrolactone by titanium alkoxide, thus reducing the loading of titanium alkoxide catalyst, which may diminish this side reaction . All structures were also observed in other samples, PDOA0, PDOA5D, PDOA7D, and PDO10D, as shown in Figures S10, S12–S14.…”

“…Similar results were also observed in a previous study where minor amounts of monohydroxylic polymers were generated from the initiation of β-butyrolactone by titanium alkoxide, thus reducing the loading of titanium alkoxide catalyst, which may diminish this side reaction. 57 All structures were also observed in other samples, PDOA0, PDOA5D, PDOA7D, and PDO10D, as shown in Figures S10, S12−S14. Polyesters containing THFA exhibited mono-alcohol THFA terminal groups (Figures S18−S20).…”

Turning CO/CO2-containing industrial process gas into valuable building blocks for the polyurethane industry

“…Both are useful intermediates, in general, and valuable monomers for the formation of polymeric ester compounds, in particular. 14–21 Nevertheless, the polyesters of β-lactones are considered to be less stable, since degradation to acrylic acid derivatives is a typical thermally induced side reaction. 14,16,17,19 To ensure a sufficient shelf-life and to address a maximized CO-content of the product the focus of the Carbon4PUR project was directed to the double carbonylation process producing succinic anhydride (SA) from ethylene oxide (EO).…”

Living ring-opening polymerization of β-butyrolactone initiated by mononuclear zirconium compounds containing sterically hinderedN,O-chelate and anionic dimethylamide ligands

“…[5][6][7][8] Particularly, metal-compound-initiated ROP of BBL is of interest due to its high molecular weight, narrow polydispersity, and controlled tacticity of the resulting PHB. Main-group metals such as Sn, [9][10][11] Al, [12][13][14] and In, [15][16][17] as well as transition metals like Zn, [18][19][20][21] Cr, 3,4,22,23 Ti, [24][25][26] and Zr, [26][27][28][29][30] and rare earth metal compounds have all been used in BBL polymerization. [31][32][33] Zr compounds, which can have coordination numbers of 6, 7, or 8, have been of particular interest due to their low toxicity, [34][35][36] colorless character of the initiator, and high activity.…”

“…5–8 Particularly, metal-compound-initiated ROP of BBL is of interest due to its high molecular weight, narrow polydispersity, and controlled tacticity of the resulting PHB. 4–36…”