Method for direct ammonolysis of polycarbonate-containing materials and products

Patent metadata

Field	Value
Publication number	US-2016168063-A1
Application number	US-201615049370-A
Country	US
Kind code	A1
Filing date	Feb 22, 2016
Priority date	Oct 15, 2013
Publication date	Jun 16, 2016
Grant date	—

Abstract

A method for recovering a dihydroxy aromatic compound and urea from a polycarbonate-containing composition comprising a polycarbonate and a phosphorus-containing flame retardant, comprising contacting the composition with ammonia in the presence of a swelling solvent for a time sufficient to depolymerize the polycarbonate producing a dihydroxy aromatic compound and urea.

First claim

I/We claim:

1 . (canceled)

2 . The method of claim 22 , wherein the composition comprises from 10 to 90 weight percent polycarbonate.

3 . The method of claim 22 , wherein the composition comprises from 10 to 70 weight percent polycarbonate.

4 . The method of claim 22 , wherein the composition comprises from 20 to 50 weight percent polycarbonate.

5 . The method of claim 22 , wherein the composition comprises from 12 to 30 weight percent polycarbonate.

6 . (canceled)

7 . The method of claim 22 , wherein the C 1-10 alcohol is methanol.

8 . (canceled)

9 . (canceled)

10 . The method of claim 22 , wherein the polycarbonate is bisphenol A polycarbonate, and the dihydroxy aromatic compound is bisphenol-A.

11 . The method of claim 22 , wherein the phosphorus-containing flame retardant is bisphenol A bis(diphenyl phosphate), resorcinol bis (diphenyl phosphate), or a combination thereof.

12 . A method for the manufacture of a polycarbonate, the method comprising recovering the dihydroxy aromatic compound generated in claim 22 , and polymerizing the dihydroxy aromatic compound and a carbonyl source to provide the polycarbonate.

13 . (canceled)

14 . (canceled)

15 . (canceled)

16 . (canceled)

17 . (canceled)

18 . The method of claim 22 , wherein the dihydroxy aromatic compound is further processed to reduce the color thereof.

19 . The method of claim 18 , wherein the further process is selected from the group of solvent recrystallization or exposure to adsorbent or chelants to bind impurities.

20 . (canceled)

21 . (canceled)

22 . A method for recovering a dihydroxy aromatic compound from a polycarbonate-containing composition comprising a polycarbonate and a component comprising a phosphorus-containing flame retardant, or acrylonitrile-butadiene-styrene, or a combination of the phosphorus-containing flame retardant and acrylonitrile-butadiene-styrene, the method comprising:
contacting the polycarbonate-containing composition with ammonia for a time sufficient to depolymerize the polycarbonate to provide a dihydroxy aromatic compound and urea in a liquid phase and a solid residual polymeric composition having dihydroxy aromatic compound adhering to its surface; separating the solid residual polymeric composition from the liquid phase; and washing the solid polymeric composition with a C 1-10 alcohol to recover additional dihydroxy aromatic compound.

23 . The method of claim 22 , wherein the liquid solution is subjected to distillation to remove ammonia, methanol, and most of the water.

24 . The method of claim 23 , wherein upon distillation, the ammonia salt of the dihydroxy aromatic compound is recovered as a solid.

25 . The method of claim 24 wherein the ammonia salt of the dihydroxy aromatic compound is converted to the dihydroxy aromatic compound by treatment with water and heat.

26 . The method of claim 25 wherein the dihydroxy aromatic compound is separated by filtration from urea in water.

Assignees

• Saudi Basic Ind Corp

Inventors

• Stanislaus Alexander
• Ganapathy Bhotla Venkata Ramanarayanan
• Sreenivasan Ps
• Bell Philip Wesley

Classifications

• C08J11/16 Primary

  by treatment with inorganic material (C08J11/14 takes precedence) · CPC title

• C08J2369/00

  Characterised by the use of polycarbonates; Derivatives of polycarbonates · CPC title

• C07C37/685 Primary

  Processes comprising at least two steps in series · CPC title

• C08G64/38

  using other monomers · CPC title

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title