Hydrogenation of tyrosine derived polyarylates

1. A method for synthesizing a polyarylate having the formula:

the method comprising:

dissolving a second polyarylate having the formula:

with DMF in a flask to produce a first solution;

starting a flow of nitrogen;

adding a catalyst to the first solution to produce a polymer solution;

starting a flow of hydrogen;

filtering the polymer solution through a filtration agent to produce a filtrate; and

adding the filtrate to water and stirring to precipitate the polyarylate,

wherein a first amount of the catalyst is added to the first solution to produce a first catalyst suspension,

wherein a second amount of the catalyst is added to the first catalyst suspension to produce a second catalyst suspension, and

wherein a third amount of the catalyst is added to the second catalyst suspension to produce a third catalyst suspension.

2. A method as recited in claim 1 , wherein the first amount is greater than the second amount and the second amount is greater than the third amount.

3. A method as recited in claim 1 , wherein:

the first catalyst suspension is stirred for about 5.5 hours before adding the second amount of the catalyst to the first catalyst suspension;

the second catalyst suspension is stirred overnight before adding the third amount of the catalyst to the second catalyst suspension; and

the third catalyst solution is in suspension for about 1.75 hours.

4. A method as recited in claim 1 , further comprising drying the polymer shreds under a stream of air for about 24 hours and then under vacuum.

5. A method as recited in claim 1 , wherein the first solution includes DMF and a solvent.

6. A method as recited in claim 5 , wherein the solvent comprises methanol or acetic acid.

7. A method as recited in claim 5 , wherein the solvent comprises 20% of the first solution by volume.

8. A method as recited in claim 1 , further comprising monitoring the method using a viscosity measurement.

9. A method as recited in claim 8 , further comprising adding more of the catalyst based on the viscosity measurement.

10. A method as recited in claim 8 , wherein the viscosity measurement is obtained using an online viscometer.

11. A method as recited in claim 1 , further comprising monitoring the method using infrared spectra.

12. A method as recited in claim 1 , further comprising monitoring the method by measuring toluene.

13. A method as recited in claim 1 , further adding a scavenger to remove leached catalyst.

14. A method as recited in claim 13 , wherein the scavenger is added before the polymer solution is filtered.

15. A method as recited in claim 13 , wherein the scavenger comprises a metal scavenger.

16. A method as recited in claim 1 , further adding insoluble high surface area particles to the polymer solution produced by adding the catalyst to the first solution.

17. A method as recited in claim 16 , wherein the insoluble high surface area particles comprise BaSO 4 , silica gel, ion exchange resins, or combinations thereof.

18. A method as recited in claim 1 , further comprising monitoring the method using an iodine compound to monitor the amount of dissolved catalyst, wherein the iodine compound is KI or NaI.

19. A method for synthesizing a polyarylate having the formula:

the method comprising:

dissolving a second polyarylate having the formula:

with DMF in a flask to produce a first solution, the first solution comprising DMF and a solvent, the solvent comprising methanol or acetic acid;

starting a flow of nitrogen;

adding a catalyst to the first solution to produce a polymer solution;

starting a flow of hydrogen;

filtering the polymer solution through a filtration agent to produce a filtrate; and

adding the filtrate to water and stirring to precipitate the polyarylate.

20. A method for synthesizing a polyarylate having the formula:

the method comprising:

dissolving a second polyarylate having the formula:

with DMF in a flask to produce a first solution;

starting a flow of nitrogen;

adding a catalyst to the first solution to produce a polymer solution;

adding insoluble high surface area particles to the polymer solution produced by adding the catalyst to the first solution;

starting a flow of hydrogen;

filtering the polymer solution through a filtration agent to produce a filtrate; and

adding the filtrate to water and stirring to precipitate the polyarylate.

21. A method as recited in claim 20 , wherein the insoluble high surface area particles comprise BaSO4, silica gel, ion exchange resins, or combinations thereof.