Catalytic process for isomerizing metallocenes
AssigneeAlbemarle Corporation
InventorRonny W. Lin
Life of this patent
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Abstract
It has been discovered that the meso form of metallocenes can be catalytically isomerized to the racemic form of the metallocene. This is accomplished by heating an isomerization mixture formed from (i) a meso form of a bridged metallocene or a mixture of meso and racemic forms of a bridged metallocene, (ii) a Group 1 and/or 2 metal halide isomerization catalyst, and (iii) a liquid organic isomerization medium, such that at least a portion of the meso form of the metallocene is isomerized to the racemic form.
Claims30
A metallocene isomerization process which comprises heating an isomerization mixture formed from (i) a meso form of a bridged metallocene or a mixture of meso and racemic forms of a bridged metallocene, (ii) a Group 1 and/or 2 metal halide isomerization catalyst, and (iii) a liquid organic isomerization medium, such that at least a portion of the meso form of the metallocene is isomerized to the racemic form.
A process for the preparation of a chiral metallocene wherein a reaction product mixture is produced that comprises racemic and meso forms of a chiral metallocene of a transition, lanthanide or actinide metal in a liquid organic reaction medium;
- wherein a Group 1 or 2 metal halide isomerization catalyst is introduced into said mixture;
- and wherein the resultant mixture is heated such that at least 10% of the meso form of the metallocene is isomerized to the racemic form.
A process of converting meso chiral metallocene to racemic chiral metallocene, which process comprises contacting in a liquid organic medium, (i) meso metallocene of a transition, lanthanide or actinide metal in whatever chemical form and composition said meso metallocene exists when in said medium, and (ii) a Group 1 or 2 metal halide isomerization catalyst in whatever chemical form and composition said metal halide isomerization catalyst exists when in said medium, and supplying sufficient heat energy to said medium such that at least 10% of said meso metallocene is isomerized to the racemic metallocene.
Dependencies are inferred from the claim text.