Process for production of carbon artifact precursor pitch

Claim 2

A process for preparing a pitch suitable for carbon artifact manufacture characterized in that: the starting material employed is a distillate from a bottoms fraction from a thermal and/or catalytic conversion of a petroleum fraction, which bottoms fraction preferably boils in the range 200°C to 550°C; the distillate is heat-soaked at a sufficiently elevated temperature to provide a pitch; and, the heat-soaked distillate is stripped at a sub-atmospheric pressure to remove at least a portion of the heat-soaked distillate which boils below 400°C, thereby obtaining a pitch suitable for carbon artifact manufacture.

Claim 3

A process as claimed in claim 1, wherein said distillate has a boiling point in the range 150°C to 530°C, preferably 450°C to 510°C, at a pressure of 760 mm of mercury.

Claim 4

A process as claimed in claim 1 or claim 2, wherein said distillate is heat-soaked at a temperature in the range of 350°C to 500°C, preferably 390°C to 450°C, and preferably for a period up to 20 hours.

Claim 5

A process as claimed in claim 1 or claim 2, wherein the distillate is obtained by heating the bottoms fraction in the range 200°C to 300°C at a pressure in the range 250 to 500 microns of mercury.

Claim 6

A process as claimed in any preceding claim, wherein said heat-soaking is conducted in an inert atmosphere or hydrogen atmosphere.

Claim 7

A process as claimed in any preceding claim, wherein the stripping is so conducted as to remove from 20% to 60% of the heat-soaked distillate boiling below 400°C.

Claim 8

A process as claimed in claim 6, wherein the stripping is conducted at 320°C to 380°C and at a pressure of 1 to 100 mm of mercury.

Claim 9

A process as claimed in any preceding claim, wherein the stripped pitch is treated with an organic solvent system having a solubility parameter at 25°C of between 8.0 and 9.5, said treating being at a temperature and with an amount of organic solvent system sufficient to provide a solvent-insoluble fraction which is thermally convertible into a deformable pitch containing greater than 75% of an optically anisotropic phase; and separating said solvent-insoluble fraction as the required product.

Claim 10

A process as claimed in any one of claims 1 to 7, wherein the stripped product is further treated by adding an organic fluxing liquid to provide a fluid pitch containing insoluble solids suspended therein, said organic fluxing liquid being employed in the range from 0.5 to 3 parts by weight of liquid per part of pitch product; thereafter filtering to separate said solids; treating the separated fluid pitch with an organic solvent system having a solubility parameter of 25°C between 8.0 and 9.5, said treating being at a temperature with an amount of organic solvent system sufficient to provide a solvent-insoluble fraction which is thermally convertible into a deformable pitch containing greater than 75% of an optically anisotropic phase; and separating said solvent insoluble fraction as the required product.