Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
150 words
A process of preparing a precursor of an optically anisotropic deformable pitch by treating a carbonaceous isotropic pitch with an organic solvent system having a solubility parameter between 8.0 and 9.5, said solvent being employed in an amount sufficient to provide a solvent insoluble fraction which is capable of being converted into an optically anisotropic pitch having greater than 75% optically anisotropic phase when heated for less than 10 minutes at about 30 0 above the point where the material becomes liquid; characterized by adding a dealkylation catalyst, and a solubilizing agent for the catalyst if required, to the organic solvent system and reacting the catalyst and the pitch in the solvent system at a temperature preferably up to 250°C, and for a time sufficient to permit an increase in the amount of the solvent insoluble fraction of the pitch; thereafter isolating the solvent insoluble fraction as the precursor product.
Claim 2
Dependent Claim
150 words
A process of preparing a precursor of an optically anisotropic deformable pitch by treating a carbonaceous isotropic pitch with an organic solvent system having a solubility parameter between 8.0 and 9.5, said solvent being employed in an amount sufficient to provide a solvent insoluble fraction which is capable of being converted into an optically anisotropic pitch having greater than 75% optically anisotropic phase when heated for less than 10 minutes at about 30 0 above the point where the material becomes liquid; characterized by adding a dealkylation catalyst, and a solubilizing agent for the catalyst if required, to the organic solvent system and reacting the catalyst and the pitch in the solvent system at a temperature preferably up to 250°C, and for a time sufficient to permit an increase in the amount of the solvent insoluble fraction of the pitch; thereafter isolating the solvent insoluble fraction as the precursor product.
Claim 3
Dependent Claim
25 words
A process as claimed in claim 1, characterized in that the dealkylation catalyst is selected from heavy metal halides, Lewis acids, and Lewis acid salts.
Claim 4
Dependent Claim
39 words
A process as claimed in claim 2, characterized in that the dealkylation catalyst is selected from (a) chlorides and bromides of tin, iron, zinc and copper; (b) aluminium chloride or boron trifluoride; (c) etherates and aminates of boron trifluoride.
Claim 5
Dependent Claim
37 words
A process as claimed in any preceding claim, characterized in that the dealkylation catalyst is employed in an amount of from 0.2% to 5.0 wt.%, preferably 1% to 2 wt.%, based on the weight of the pitch.
Claim 6
Dependent Claim
26 words
A process as claimed in any preceding claim, characterized in that the said temperature of the reaction is the boiling point of the organic solvent system.
Claim 7
Dependent Claim
22 words
A process as claimed in any preceding claim, characterized in that the reaction is combusted at a temperature of 30°C to 250°C.
Claim 8
Dependent Claim
32 words
A process as claimed in any preceding claim, characterized in that from 5 to 150 ml, preferably 10 to 20 ml, of the solvent system is employed per gram of the pitch.
Claim 9
Dependent Claim
35 words
A process as claimed in any preceding claim, characterized in that a solubilizing amount of acetone, nitrobenzene, or an organic ether is employed when the dealkylation catalyst is zinc chloride, aluminium chloride or boron trifluoride.