Dimethyl carbonate (DMC) is an environmentally benign chemical currently produced using CO 2 . Using the conventional Dean-Stark apparatus, a method was developed for the effective and selective removal of the methanol generated in the transesterification of DMC with alcohol. Using this device, various diols (HO-A-OH; A 5 (CH 2 ) 4 , (CH 2 ) 2 O(CH 2 ) 2 , CH 2 C 6 H 10 CH 2 , and CH 2 C 6 H 4 CH 2 ) were converted to mixtures of the corresponding MeOC (O)[O-A-OC(O)]OMe and MeOC(O)[O-A-OC(O)] 2 OMe. Dialkyl carbonates such as dibutyl carbonate, dibenzyl carbonate, and diallyl carbonate were also efficiently prepared from the corresponding alcohols using this device. The compound prepared from 1,4-butanediol, MeOC(O)[O(CH 2 ) 4 OC(O)] 1.5 OMe, was subjected to polycondensation with HO(CH 2 ) 4 [O 2 CC 6 H 4 CO 2 (CH 2 ) 4 ] 1.5 OH or HO(CH 2 ) 4 [O 2 CC 6 H 4 CO 2 (CH 2 ) 4 ] 1.8 OH, which directly was prepared from terephthalic acid and 1,4-butanediol. The polycondensation afforded high-molecular-weight poly(1,4-butylene carbonate-co-terephthalate)s (PBCTs) with M w of 80-270 kDa and 0.40-0.46 terephthalate mole fractions. PBCTs are attractive materials with potential biodegradability and LDPE-like thermal properties.

The Me2Si-bridged ansa-Cp/amido half-metallocene, [Me2Si(η5-Me4C5)(NtBu)]TiCl2, termed a “constrained-geometry catalyst (CGC)”, is a representative homogeneous Ziegler catalyst. CGC derivatives with the [1,2]azasilinane framework, in which the amide alkyl substituent is joined by the Si-bridge, were prepared, and the catalytic performances of these species was studied. Me4C5HSi(Me)(CH2CH=CH2)-NH(C(R)(R’)CH=CH2) (R, R’ = H or methyl; Me4C5H = tetramethylcyclopentadienyl) was susceptible to ring closure metathesis (RCM) when treated with Schrock’s Mo-catalyst to afford -Si(Me4C5H)(Me)CH2CH=CHC(R)(R’)NH- containing a six-membered ring framework. Using the precursors and the products of RCM, various CGC derivatives, i.e., [-Si(η5-Me4C5)(Me)CH2CH=CHC(R)(H)N-]TiMe2 (13, R = H; 15, R = Me), [-Si(η5-Me4C5)(Me)CH2CH2CH2CH2N]TiMe2 (14), [(η5-Me4C5)Si(Me)(CH2CH=CH2)NCH2CH=CH2]TiMe2 (16), [(η5-Me4C5)Si (Me)(CH=CH2)NCH2CH=CH2]TiMe2 (17), and [(η5-Me4C5)Si(Me)(CH2CH3)NCH2CH2CH3]TiMe2 (18), were prepared. The catalytic activity of the newly prepared complexes was lower than that of CGC when activated with [Ph3C][B(C6F5)4]/iBu3Al. However, the catalytic activity of these species was improved by using tetrabutylaluminoxane ([iBu2Al]2O) instead of iBu3Al and the activity of 14/[Ph3C][B(C6F5)4]/[iBu2Al]2O was comparable to that of CGC/[Ph3C][B(C6F5)4]/iBu3Al (4.7 and 5.0 × 106 g/mol-Ti, respectively). Advantageously, the newly prepared complexes produced higher molecular weight poly(ethylene-co-1-octene)s than CGC.

The condensation of a mixture of dimethyl carbonate and phthalate derivatives with 1,4‐butanediol (BD), catalyzed by sodium alkoxide, generated high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s with molecular weights (Mn) of 50–120 kDa. The subsequent addition of polyols [BD, glycerol propoxylate, 1,1,1‐tris(hydroxymethyl)ethane, or pentaerythritol] chopped these high‐molecular weight polymers to afford macrodiols or macropolyols with facile control of their molecular weights (Mn, 2000–3000 Da) and unique chain topological compositions. Macropolyols prepared by chopping poly(1,4‐butylene carbonate‐co‐terephthalate) were waxy in nature, whereas those containing isophthalate and phthalate units were oily. The macropolyols synthesized by this chopping method may have potential applications in the polyurethane industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43754.