# US 10,767,006 B2 · Hydrogenation of tyrosine derived polyarylates

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,767,006 B2
- Document ID: US10767006B2
- Status: Granted
- Kind: B2
- Application number: 15/972,855
- Filed: 2018-05-07
- Published: 2018-12-13
- Granted: 2020-09-08
- Earliest claimed: 2017-06-07
- Assignees: Medtronic, Inc.
- Applicants: TYRX, Inc.
- Inventors: Satish Pulapura; Dan Thanh Le; Xiangji Chen; Suping Lyu; Fatima Buevich
- Web page: https://patentgrep.com/patent/US10767006B2

## CPC

- C08G 63/91: Polymers modified by chemical after-treatment
- C08G 63/6856: {Dicarboxylic acids and dihydroxy compounds}
- C08G 63/916: {Dicarboxylic acids and dihydroxy compounds}
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A method for hydrogenating tyrosine derived polyarylates includes dissolving a second polyarylate with DMF in a flask to produce a first solution. A catalyst is added to the first solution to produce a polymer solution. The polymer solution is filtered through a Celite bed to produce a filtrate. The filtrate is added to water and stirred to precipitate the polyarylate.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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

### Claim 6 (depends on 5)

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

### Claim 7 (depends on 5)

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

### Claim 8 (depends on 1)

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

### Claim 9 (depends on 8)

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

### Claim 10 (depends on 8)

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

### Claim 11 (depends on 1)

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

### Claim 12 (depends on 1)

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

### Claim 13 (depends on 1)

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

### Claim 14 (depends on 13)

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

### Claim 15 (depends on 13)

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

### Claim 16 (depends on 1)

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.

### Claim 17 (depends on 16)

A method as recited in claim 16, wherein the insoluble high surface area particles comprise BaSO4, silica gel, ion exchange resins, or combinations thereof.

### Claim 18 (depends on 1)

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.

### Claim 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.

### Claim 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.

### Claim 21 (depends on 20)

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