The Ultrasmall Palladium Nanoparticles Catalyzed Telomerization of CO₂ with 1,3‐Butadiene at Room Temperature: Selective Synthesis of δ‐Lactone

Abstract

An efficient method for the selective synthesis of δ-lactone from CO 2 and 1,3-butadiene was developed by using ultrasmall palladium nanoparticles as a catalyst for the first time. Palladium nanoparticles (1.90 � 0.39 nm) were generated in situ in the presence of Pd(acac) 2 , tetrabutylammonium acetate (TBAAc), and PPh 3 as the precatalyst, stabilizer, and reductant, respectively. Maximum yield (86 % with 96 % selectivity) with satisfactory conversion (89 %) and turnover number (1271) was achieved under mild conditions.

Ring-Opening Polymerization of CO2-Based Disubstituted δ-Valerolactone toward Sustainable Functional Polyesters

“…3-Ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVL) has the advantages of economic and nontoxic resource supply as a product from the direct reaction of carbon dioxide with 1,3butadiene with the conversion and telomerization selectivity of 86% and 95%, respectively. 1 As a substituted δ-lactone containing two vinyl groups, EVL is an excellent monomer for ring-opening polymerization (ROP) to produce degradable aliphatic polyesters. The ROP of EVL is not only a novel approach toward functional polyesters, but also an alternative of CO 2 fixation producing copolymers of CO 2 with 1,3butadiene differing from the copolymerization of CO 2 with epoxides resulting in polycarbonates.…”

“…The carbon signals at 134.9 (C F ) and 123.2 (C G ) ppm are attributed to the CC double bond in the allylic ester of EVL, while those of the tiglate ester appear at 137.4 (C H ) and 131.2 ppm (C J ), which is further confirmed by the 1 H− 13 C HSQC NMR spectrum (Figure S5). The carbon signals of the carbonyl of BBL appear at 169.5 (C L* ) and 170.2 ppm (C L ), 1 H NMR (a, run 6 in Table 1), 13 C NMR (b, run 6 in Table 1, peak * is attributed to the allyl end groups formed by the rearrangement of BBL end), DOSY NMR spectra (c, run 4 in Table 1) and MALDI-ToF MS of poly(EVL-r-BBL) (d, run 4 in Table 1) with a zoom-in view (e) and the corresponding chemical structures (f). according to the fact that x does not exceed y + 1 in all chains in the MALDI-ToF results.…”

“…The transmission electron microscopy (TEM) image also supports their spherical morphologies with two diameter ranges of 20−30 and 60−200 nm (Figure 3c), which is consistent with DLS results. 1 H NMR (Figure S14) shows both PSar signals and poly(EVL-r-BBL) signals with some residual unsaturated bonds. SEC curves (Figure S15) indicate that two major kinds of macromolecules are formed under the condition ([PSar-SH] 0 :[poly(EVL-r-BBL)] 0 = 2:1) with one or two grafted PSar chains, that is, poly(EVL-r-BBL)-g-PSar and poly(EVL-r-BBL)-g-(PSar) 2 .…”

“…Figure 1. Chemical structures, NMR spectra, and MALDI-ToF MS of EVL and poly(EVL-r-BBL) 1. H NMR (a, run 6 in Table1),13 C NMR (b, run 6 in Table1, peak * is attributed to the allyl end groups formed by the rearrangement of BBL end), DOSY NMR spectra (c, run 4 in Table1) and MALDI-ToF MS of poly(EVL-r-BBL) (d, run 4 in Table1) with a zoom-in view (e) and the corresponding chemical structures (f).…”

“…c Determined by 1 H NMR of the product mixture (FigureS1and eqs S1 and S2). d Mol %, determined by1 H NMR of the product mixture (FigureS1and eq S3). e M w and dispersity were determined by SEC.…”