Monomers issued from renewable resources and process for polymerising them
This invention relates to the synthesis of polycarbonates prepared from carbonate monomers derived from the biomass in the presence of a system comprising an organometallic transfer agent and alcohol. It also relates to the polymers resulting from these cyclic compounds.
1. A process for polymerising five- or six-membered cyclic carbonates to prepare homo- or co-polymers of carbonate by ring-opening polymerisation in the presence of a system comprising an organometallic compound and alcohol, wherein a ratio of monomer/metal ranges between 1000 and 100,000, wherein a number average molecular weight Mn of the final polymer increases with increasing monomer/alcohol ratio, and wherein the carbonate is a five- or six-membered cyclic carbonate selected from 2-oxy-trimethylenecarbonate (OTMC) or dehydrotrimethylenecarbonate (DHTMC).
2. The process of claim 1 , wherein the organometallic compound is selected from metallic complexes of formula MR n wherein M is a metal Group 2, 3 (including the lanthanide series), 8, 12 or 13 of the periodic Table, wherein each R is selected independently from hydrogen, a linear or branched hydrocarbyl radical having from 1 to 12 carbon atoms, an alkoxide group OR* wherein R* is a linear or branched hydrocarbyl having from 1 to 12 carbon atoms, an amido group NR** 2 wherein each R** is independently of general formula YR # 3 wherein Y is Si or C and each R # is independently selected from hydrogen or hydrocarbyl having from 1 to 12 carbon atoms, a borohydride group or an halide, and wherein n is the valence of M.
3. The process of claim 2 , wherein M is Mg(II), Ca(II), Y(III), Fe(II), Fe(III), Zn(II), or Al(III).
4. The process of claim 2 , wherein each R is selected independently from an amido group, an alkoxide group OR′, or a borohydride group (BH 4 ).
5. The process of claim 1 , wherein the organometallic compound is a single-site catalyst component based upon a bulky β-diiminate ligand (BDI) represented by general formula
wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are each independently selected from hydrogen, unsubstituted or substituted hydrocarbyl, or inert functional group, wherein two or more of said groups can be linked together to form one or more rings, wherein X is an hydrocarbyl radical having from 1 to 12 carbon atoms, an alkoxide group OR*, an amido group NR** 2 or a borohydride group (BH 4 ).
6. The process of claim 1 , wherein the organometallic compound is selected from [BDI]Zn(N(SiMe3)2), {[BDI]Zn(OiPr),}2, Zn(N(SiMe3)2), ZnEt2, Y(N(SiMe3)2), Y(OiPr)3, and Al(OiPr)3.
7. The process of claim 1 , wherein the alcohol is R′OH wherein R′ is an hydrocarbyl, linear or branched, having from 1 to 20 carbon atoms and wherein the monomer/alcohol ratio is of from 25 to 2500.
8. The process of claim 1 , wherein the alcohol is isopropyl (iPr) or benzyl (Bn).
9. The process of claim 1 , wherein the alcohol additionally contains a functional group that is capping the end of each polycarbonate chain.
10. The process of claim 1 , wherein the amount of metal catalyst is selected to obtain a ratio of monomer/metal of from 1000 to 10000.