Process for the purification of dihydric phenols

1. A method for purifying a dihydric phenol, the method comprising:

dissolving a dihydric phenol having Formula (I)

wherein R is a hydrogen atom or an aliphatic functionality having 1 to 6 carbon atoms; and n is an integer having a value of 1 to 4, in a solvent to form a solution A;

contacting the solution A with an adsorbent material selected from the group consisting of metal oxides, modified metal oxides, activated carbons, and clays, wherein the step of contacting is carried out at a temperature of about 25° C. to about 120° C;

filtering the adsorbent material to form a solution B;

adding an anti-solvent to the solution B to form a solution C, wherein the anti-solvent has a higher boiling point than the solvent; and

distilling the solution C until about 10 to 80% of the original weight of the solvent is removed.

2. The method of claim 1 , further comprising isolating a purified dihydric phenol.

3. A method for purifying a dihydric phenol, the method comprising:

dissolving a dihydric phenol having Formula (I)

wherein R is a hydrogen atom or an aliphatic functionality having 1 to 6 carbon atoms; and n is an integer having a value of 1 to 4, in a mixture of a solvent and an anti-solvent to form a solution A, wherein the anti-solvent has a higher boiling point than the solvent;

contacting the solution A with an adsorbent material selected from the group consisting of metal oxides, modified metal oxides, activated carbons, and clays, wherein the step of contacting is carried out at a temperature of about 25° C. to about 120° C.;

filtering the adsorbent material to form a solution B; and

distilling the solution B until about 10 to 80% of the original weight of the solvent is removed.

4. The method of claim 3 , further comprising isolating the purified dihydric phenol.

5. The method of claim 1 , wherein the dihydric phenol is 2-methyl-1,4-hydroquinone.

6. The method of claim 1 , wherein the solvent comprises water, ketones having 3 to 10 carbons, alcohol having 1 to 12 carbons, esters having 4 to 10 carbons; or mixtures of one or more of the foregoing solvents.

7. The method of claim 1 , wherein the solvent comprises acetone.

8. The method of claim 1 , wherein the anti-solvent comprises hydrocarbon solvents having 6 to 20 carbons.

9. The method of claim 1 , wherein the anti-solvent comprises toluene.

10. The method of claim 1 , wherein the metal oxide comprises silica, zirconia, magnesia, or alumina.

11. The method of claim 1 , wherein the modified metal oxide comprises water-washed silica or acid-washed silica.

12. The method of claim 1 , wherein the clay comprises Engelhardt clay, montmorillonite or hydrotalcite.

13. The method of claim 1 , wherein the adsorbent is present in an amount of about 2 percent by weight to about 30 percent by weight, relative to an amount of the dihydric phenol.

14. The method of claim 1 , wherein the solvent is present in an amount of about 0.5 grams to about 10 grams, per gram of the dihydric phenol.

15. The method of claim 1 , wherein the anti-solvent is present in an amount of about 2 grams to about 40 grams, per gram of the dihydric phenol.

16. The method of claim 3 , wherein the adsorbent is present in an amount of about 2 percent by weight to about 30 percent by weight, relative to an amount of the dihydric phenol.

17. The method of claim 3 , wherein the solvent is present in an amount of about 0.5 grams to about 10 grams, per gram of the dihydric phenol.

18. The method of claim 3 , wherein the anti-solvent is present in an amount of about 2 grams to about 40 grams, per gram of the dihydric phenol.

19. A purified dihydric phenol prepared in accordance with the method of claim 1 .

20. A polymer comprising structural units derived from the purified dihydric phenol of claim 19 .

21. A purified dihydric phenol prepared in accordance with the method of claim 3 .

22. A polymer comprising structural units derived from the purified dihydric phenol of claim 21 .