Catalysts for the preparation of carbonates from epoxides and CO
A macrocycle based on β-diketimines, a process for preparing the inventive macrocycle, an uncharged macrocyclic dimetallic complex based on the inventive macrocycle, and a process for preparing the uncharged macrocyclic dimetallic complex, the use of the uncharged macrocyclic dimetallic complex as a polymerization catalyst in the polymerization of carbon dioxide with one or more epoxides, a process for preparing polycarbonates by reacting carbon dioxide with one or more epoxides in the presence of the inventive uncharged macrocyclic dimetallic complex, and a polycarbonate prepared by the process according to the invention.
1. An uncharged macrocyclic dimetallic complex of the general formula (V)
in which
R 1 , R 2 , R 4 and R 5 are each independently H, C 1 -C 10 -alkyl, C 1 -C 10 -fluoroalkyl, C 6 -C 20 -fluoroaryl, C 1 -C 10 -alkoxy or C 6 -C 20 -aryl;
R 3 and R 6 are each independently H, C 1 -C 10 -alkyl, halogen radical, pseudohalogen radical, carboxylic ester radical, carboxylic ester radical, sulfonyl group or C 6 -C 20 -aryl;
R 7 , R 8 , R 9 and R 10 are each independently H, C 1 -C 10 -alkyl, C 1 -C 10 -fluoroalkyl, C 1 -C 10 -alkoxy or C 6 -C 20 -aryl;
R 11 , R 12 , R 13 and R 14 are each independently H, C 1 -C 10 -alkyl, C 1 -C 10 -fluoroalkyl, C 6 -C 20 -aryl, halogen, pseudohalogen, C 1 -C 10 -alkoxy- or C 6 -C 20 -aryloxy;
m, n are each independently 1 to 20;
o, p, q and r are each independently 0, 1, 2, 3 or 4;
M is a metal of group 6, 8, 9, 10, 11 or 12 of the periodic table of the elements (IUPAC nomenclature);
L is a monodentate, singly negatively charged ligand;
x, depending on the oxidation state and coordination number of the metal M, is 0, 1, 2 or 3.
2. An uncharged macrocyclic dimetallic complex according to claim 1 , wherein
M is Zn;
L is —N(SiMe 3 ) 2 , —OAc, OR 15 , —SO 2 R 15 , halogen, such as F, Cl or Br, or hydrogen;
R 15 is C 1 -C 10 -alkyl or C 6 -C 20 -aryl; and
x is 1.
3. A process for preparing an uncharged macrocyclic dimetallic complex according to claim 1 comprising preparing a macrocycle of the general formula (I)
in which:
R 1 , R 2 , R 4 and R 5 are each independently H, C 1 -C 10 -alkyl, C 1 -C 10 -fluoroalkyl, C 6 -C7 0 -fluoroaryl, C 1 -C 10 -alkoxy or C o -C/ o -aryl;
R 3 , R 6 are each independently H, C 1 -C 10 -alkyl, halogen radical, pseudohalogen radical, carboxylic ester radical, sulfonyl group or C 6 -C 20 -aryl;
R 7 , R 8 , R 9 and R 10 are each independently H, C 1 -C 10 -alkyl, C 1 -C 10 -fluoroalkyl, C 1 -C 10 -alkoxy or C 6 -C 20 -aryl;
R 11 R 12 , R 13 , and R 14 are each independently H, C 1 -C 10 -fluoroalkyl, C 6 -C 20 -aryl, halogen, pseudohalogen, C 1 -C 10 -alkoxy or C 6 -C 20 -araryloxy;
m, n are each independently 1 to 20;
o, p, q and r are each 0, 1, 2, 3 or 4
by:
i)reacting β-diketones of the formulae (IIa) and (IIb)
with a diamino compound of the formula (IIIa)
to obtain a product of the formula (IV)
ii) reacting the product of the formula (IV) with a compound of the formula (IIb)
and reacting the macrocycle of the formula (I) with a metal compound of the general founula (VI)
M(L x ) 2 (VI)
in which
M is a metal of group 6, 8, 9, 10, 11 or 12 of the periodic table of the elements (IUPAC nomenclature);
L is a monodentate, singly negatively charged ligand;
x is 0, 1, 2 or 3.
4. A process for preparing polycarbonates by reacting carbon dioxide with one or more epoxides in the presence of an uncharged macrocyclic dimetallic complex of the formula (V) according to claim 1 .
5. The process according to claim 4 , wherein the epoxide(s) is/are selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, cyclopentene oxide, cyclohexene oxide, cycloheptene oxide, 2,3-epoxypropyl phenyl ether, epichlorohydrin, epibromohydrin, i-butene oxide, styrene oxide, glycidyl ether, glycidyl ester and acryloyl oxides.
6. The process according to claim 5 , wherein propylene oxide and/or cyclohexene oxide is/are used as epoxides.
7. A polycarbonate prepared by a process according to claim 4 .
8. A polycarbonate according to claim 7 , which is a polycarbonate selected from the group consisting of polypropylene carbonate, polycyclohexene carbonate and poly(propylene-cyclohexene).