Polycarbonates Derived from Green Acids: Ring-Opening Polymerization of Seven-Membered Cyclic Carbonates

Abstract

Methyl substituted seven-membered ring carbonates (7CCs), namely, 4-methyl-and 5-methyl-1,3-dioxepan-2-one (R-Me7CC and β-Me7CC), have been synthesized in high yields (up to 70%) upon cyclization of the corresponding R,ω-diols issued from green renewable acids. ("Immortal") ring-opening polymerization of these monomers has been carried out using various catalysts combined with an alcohol acting as a co-initiator and a chain transfer agent. The Lewis acid Al(OTf) 3 , the organometallic complexes [(BDI iPr )Zn(N(SiMe 3 ) 2 )] ((BDI iPr ) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)-imino)-2-pentene] and [(ONOO tBu )Y(N(SiHMe 2 ) 2 )(THF)] (ONOO tBu = amino-alkoxy-bis(phenolate)) or the organic 4-N,N-dimethylaminopyridine (DMAP), 1.5.7-triazabicyclo-[4.4.0]dec-5-ene (TBD) or 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) successfully afforded the corresponding poly(R-and β-Me7CC)s with quite good control and activities. The dissymmetry of the monomers raises the question of catalyst selectivity in the ring-opening of the 7CCs. Detailed microstructural analyses of the poly(7CC)s using 1 H and 13 C NMR and MALDI-ToF-MS techniques revealed (1) the higher regioselectivity -with preferential ring-opening at the most hindered oxygen-acyl O-C(O)O bond, that is, closest to the R-Me substituentof the zinc-based system followed by the yttrium, as compared to the lack of selectivity of the aluminum one, in the ring-opening polymerization (ROP) of R-Me7CC; (2) the absence of regioselectivity in the ROP of β-Me7CC, whichever the catalyst system used, most likely as a result of the OC(O)O further remote substitution site; (3) the expected R-hydroxy,ω-alkoxyester chain ends. Differential scanning calorimetry (DSC) analyses of these polymers underlined the influence of the position of the methyl substituent on the glass transition temperature. Noteworthy, this study represents the first synthesis of the β-Me7CC monomer and of the resulting polycarbonates.

On the Versatility of Urethane/Urea Bonds: Reversibility, Blocked Isocyanate, and Non-isocyanate Polyurethane

“…239 The ratio between secondary and primary hydroxyl compound is determined by substituents introduced at the α-methylene of the bicyclocarbonate 98: a more electronwithdrawing group draws the reaction toward secondary hydroxyl containing product 99 (Scheme 60). 242 243 5.2.3.3. Polymer Synthesis and Properties.…”

Polymers from sugars: cyclic monomer synthesis, ring-opening polymerisation, material properties and applications

“…11). 79 Itaconic acid is industrially produced from sugars via fungal fermentation of glucose, xylose, or arabinose, using Aspergillus terreus. 80…”

Polymers from sugars and CO2: ring-opening polymerisation and copolymerisation of cyclic carbonates derived from 2-deoxy-d-ribose

“…In Fig. 9, polymer series have been differentiated and labelled so that a series contains the same number of 1α units (m = 11-18) but different numbers of TMC co-monomer (n = [11][12][13][14][15][16][17][18][19][20][21][22]. This is arbitrary and not representative of the polymerisation process, as from most signals, a higher m/z species can be found that corresponds to the addition of either a TMC or 1α unit.…”

“…The resulting residue was extracted into EtOAc, washed with water and the organic layer dried over MgSO 4 to afford the product as a colourless oil (7. 19 1-O-Methyl-2-deoxy-D-ribofuranoside-3,5-O-cis-cyclic carbonate (1). A solution of 2 (7.06 g, 23.4 mmol) in anhydrous acetonitrile (230 ml, 0.1 mol L −1 ) was saturated with CO 2 at 0°C in an ice-water bath.…”

“…12 In addition to the many metal-based catalysts, 13 a variety of simple organocatalytic systems including 4-dimethylaminopyridine (DMAP), 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 4-pyrrolidinopyridine (PPY), ureas, 14 thioureas (TU), 15 N-heterocyclic carbenes as well as various phosphines, phosphazenes 16 and organic phosphoric acids 17 have been shown to promote ROP under mild and metal-free reaction conditions. 18 Typically, cyclic carbonates for ROP are 6-membered rings though there are examples of 7-, 19 8-20 and highly strained 5-21 membered ring monomers. The usually low ring strain of 5-membered cyclic carbonates often means that forcing ROP conditions are required, which result in decarboxylation and ether linkages in the polymer backbone, detrimental to its physical properties.…”