Solvating component and solvent system for mesophase pitch

Abstract

A solvating component for a solvated mesophase pitch. The solvated component includes a mixture of aromatic hydrocarbons having boiling points in the atmospheric equivalent boiling point range of about 285° to about 500° C. (about 550° F.-932° F.). At least 80% of the carbon atoms of the hydrocarbons are aromatic as characterized by carbon 13 NMR. The aromatic hydrocarbons are selected from a group consisting of aromatic compounds having 2 to 5 aromatic rings, substituted aromatic compounds having 2 to 5 aromatic rings wherein said substituents are alkyl groups having 1 to 3 carbons, hydroaromatic compounds having 2 to 5 rings, substituted aromatic compounds having 2 to 5 rings wherein said substituents are alkyl groups having 1 to 3 carbons, and mixtures thereof.

What is claimed is:  
     
         1 . A process for producing high melting mesogens, said process comprising: 
 combining a first aromatic carbon solvent system having boiling points in the atmospheric equivalent boiling point (AEBP) range of about 285° to about 500° C., at least 80% of the carbon atoms of said hydrocarbons are aromatic as characterized by carbon 13 NMR and said aromatic hydrocarbons are selected from the group consisting of (i) aromatic compounds and N, O and S heteroaromatic compounds having 2 to 5 rings, (ii) substituted aromatic compounds and N, O and S heteroaromatic compounds having 2 to 5 rings wherein said substituents are alkyl groups having 1 to 3 carbons (C 1  to C 3 ), (iii) hydroaromatic compounds and N, O and S heterohydroaromatic compounds having 2 to 5 rings, (iv) substituted hydroaromatic compounds and N, O and S heterohydroaromatic compounds having 2 to 5 rings wherein said substituents are alkyl groups having 1 to 3 carbons (C 1  to C 3 ), and (v) mixtures thereof with a second solvent system having a solubility parameter in the range of 8 to 11.5, the ratio of said first solvent system to said second solvent system ranging from 1:20 to 2:5 to form an extraction solution;    adding said extraction solution to a pitch in a solution to pitch ratio ranging from about 3:1 to about 20:1; and    extracting said pitch with said extraction solution to yield a residue of mesogens, said mesogens melting at or above a temperature of 375° C.    
     
     
         2 . A solvated mesophase pitch which comprises: 
 mesogens; and    5 to 40% of a solvating component comprising a mixture of aromatic hydrocarbons having boiling points in the atmospheric equivalent boiling point (AEBP) range of about 285° to about 500° C., at least 80% of the carbon atoms of said hydrocarbons are aromatic as characterized by carbon 13 NMR and said aromatic hydrocarbons are selected from the group consisting of (i) aromatic compounds and N, O and S heteroaromatic compounds having 2 to 5 rings, (ii) substituted aromatic compounds and N, O and S heteroaromatic compounds having 2 to 5 rings wherein said substituents are alkyl groups having 1 to 3 carbons (C 1  to C 3 ), (iii) hydroaromatic compounds and N, O and S heterohydroaromatic compounds having 2 to 5 rings, (iv) substituted hydroaromatic compounds and N, O and S heterohydroaromatic compounds having 2 to 5 rings wherein said substituents are alkyl groups having 1 to 3 carbons (C 1  to C 3 ), and (v) mixtures thereof.    
     
     
         3 . A solvated mesophase pitch as set forth in  claim 2 , wherein said solvating component is a thermally treated decant oil fraction.  
     
     
         4 . A solvated mesophase pitch as set forth in  claim 2 , wherein at least 85% of the carbon atoms of said solvating component are aromatic carbon atoms.  
     
     
         5 . The solvated mesophase pitch of  claim 2 , wherein at least 80% of the compounds of said solvating component boil within plus or minus 60° C. of the mean boiling point of said solvating component.  
     
     
         6 . The solvated mesophase pitch of  claim 2  which when spun into a fiber yields a green fiber having a diameter of less than 13 microns.  
     
     
         7 . A process for producing a thermally cracked aromatic solvating component of a solvated mesophase pitch comprising the steps of: 
 selecting an aromatic hydrocarbon having less than 80% by weight of aromatic carbons;    thermally cracking said aromatic hydrocarbon at a temperature of 400° to 540° C. and a pressure of up to 1000 psig for a time sufficient to increase the carbon content to greater than 80%; and    fractionating said thermally cracked aromatic hydrocarbon to obtain a distillate boiling in the range of 285° to 500° C.    
     
     
         8 . A green fiber comprising solvated mesophase pitch having a diameter of less than 13 microns.