Synthesis and isomerization of 1,2-bis (indenyl) ethanes

A method for converting a kinetic EBI to thermodynamic EBI which comprises:

• (i) providing a solution of a kinetic EBI in a hydrocarbon solvent first solution;
• (ii) combining said first solution with a second solution of potassium tertiary butoxide in a non-interfering ether solvent,
• wherein a third solution of kinetic EBI in a combined hydrocarbon and a non-interfering solvent is produced;
• (iii) refluxing said step (ii) third solution,
• wherein at least a portion of said kinetic EBI contained therein is converted to thermodynamic EBI.

A method which comprises:

• (i) providing a solution of kinetic EBI in a non-interfering solvent,
• (ii) converting said step (i) solution to a mixture containing solid kinetic EBI in a mother liquor solution of kinetic EBI,
• (iii) separating said solid kinetic EBI from said mother liquor solution of EBI, and
• (iv) treating said mother liquor solution of EBI with an isomerization agent
• wherein at least a portion of said kinetic EBI in solution in said mother liquor is converted to thermodynamic EBI.

A method which comprises:

• (i) reacting lithium indenide with 1,2-dibromoethane in a non-interfering, non-hydrocarbon solvent,
• wherein a first reaction mixture containing kinetic EBI in solution is produced;
• (ii) exchanging said solvent of said first reaction mixture with a hydrocarbon solvent,
• wherein a first hydrocarbon solvent solution of kinetic EBI is produced;
• (iii) reducing the temperature of said step (ii) solution to a level effective to cause precipitation of solid kinetic EBI from a second hydrocarbon mother liquor solution of kinetic EBI;
• (iv) separating said solid kinetic EBI from said second mother liquor solution thereof;
• (v) treating said mother liquor solution of kinetic 1,2-bis(indenyl(1))ethane with an isomerization agent comprising a solution of an alkali metal alkoxide having the formula MOR, wherein M is an alkali metal and R is a hydrocarbyl group having one to ten carbon atoms in a non-interfering solvent and wherein said solution contains from about 10 mol percent to about 20 mol percent of said alkali metal alkoxide,
• wherein a mother liquor solution of thermodynamic EBI is produced;
• and
• (vi) subjecting said step (v) mother liquor solution to conditions effective to cause precipitation of said thermodynamic EBI therefrom.

A method for synthesizing a 1,2-bis(indenyl)ethane which comprises:

• (i) reacting indene with an alkali metal alkyl in a non-interfering solvent at a temperature below 0° C.,
• wherein a first reaction mixture containing an alkali metal indenide and said solvent is produced;
• (ii) raising the temperature of said first reaction mixture from 20° C. to 40° C.;
• (iii) combining said step (ii) first reaction mixture at 20° C. to 40° C. with dibromoethane,
• wherein a second reaction mixture is produced and thereafter
• (iv) adding tetrahydrofuran to said second reaction mixture wherein a third reaction mixture containing EBI is produced;
• (v) adding water to said third reaction mixture,
• wherein an organic phase and an aqueous phase form;
• (vi) separating said step (v) aqueous and organic phases;
• (vii) exchanging the solvent of said organic phase separated in step (v) with a hydrocarbon solvent from which kinetic EBI is separated.

A method for synthesizing EBI which comprises:

• (i) reacting n-butyl lithium with indene at a temperature of 40° C. to 50° C.
• wherein a reaction mixture containing lithium indenide is produced;
• (ii) cooling said step (i) reaction mixture to −10° C. to −30° C.;
• (iii) adding dibromomethane to provide a second reaction mixture;
• (iv) adding tetrahydrofuran to said second reaction mixture at a temperature of −15° C. to −20° C. with agitation,
• wherein a third reaction mixture containing solid EBI a mother liquor is produced;
• and
• (v) separating solid EBI from said third reaction mixture,
• wherein a mother liquor solution of kinetic EBI is produced.

A method which comprises:

• (i) reacting lithium indenide with 1,2-dibromoethane in a diethyl ether and tetrahydrofuran solvent mixture,
• wherein a first reaction mixture containing kinetic EBI in solution in said solvent mixture is produced;
• (ii) exchanging said solvent mixture of said first reaction mixture with a hexane solvent,
• wherein a first hexane solution of kinetic EBI is produced;
• (iii) reducing the temperature of said step (ii) solution to a level effective to cause precipitation of solid kinetic EBI from a second hexane solution of said kinetic EBI;
• (iv) separating said solid kinetic EBI from said second hexane solution thereof;
• (v) treating said second hexane solution of kinetic EBI with potassium tertiary butoxide,
• wherein a hexane solution of the thermodynamic EBI is produced;
• and
• (vi) subjecting said step (v) hexane solution to conditions effective to cause crystallization of said thermodynamic EBI therefrom.