Method for making reaction products of phosgene and dihydric phenol with stable suspension of dihydric phenol, alkali metal hydroxide and water

• US 4,810,813 A
• Filed: 07/24/1987
• Issued: 03/07/1989
• Est. Priority Date: 09/08/1986
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Silva, James M., Kosky, Philip G., Fyvie, Thomas J.
• Primary Examiner(s): Anderson, Harold D.
• Application Number:
  US07/077,479
• Time in Patent Office: 592 Days
• Field of Search: 558/281, 558/280, 558/282, 528/196
• US Class Current: 558/281
• CPC Class Codes: C07C 68/02 from phosgene or haloformates
• CPC Class Codes: C07C 69/96 Esters of carbonic or haloformic acids
• CPC Class Codes: C08G 64/24 and phenols

Abstract

A method is provided for making reaction products of phosgene and dihydric phenol under interfacial reaction conditions. The dihydric phenol such as BPA is introduced into the reactor in the form of a stable suspension which reduces phosgene hydrolysis, minimizes phosgene escape and effects improved BPA metering into the reactor.

Claims

1. A continuous method for making phosgene-dihydric phenol reaction products whereby phosgene hydrolysis and back-flow are reduced comprising

(1) effecting reaction between dihydric phenol and phosgene under interfacial reaction conditions in a reaction vessel in the presence of alkali metal hydroxide, and

(2) recovering phosgene-dihydric phenol organic reaction products,

wherein the dihydric phenol is metered into the reaction vessel as a stable suspension resulting from the agitation of a mixture comprising water, alkali metal hydroxide, and dihydric phenol comprising by weight:

(A) 47.9-52.0% bisphenol-A,

(B) 52.0-47.9% water, and

(C) 0.01-0.2% alkali metal hydroxide.

2. The method of claim 1, wherein the dihydric phenol is bisphenol-A.

3. The method of claim 1, wherein the phosgene-dihydric phenol reaction product is a bischloroformate or mixture of oligomeric carbonate mono- and bischloroformates.

4. The method of claim 1, wherein the alkali metal hydroxide is sodium hydroxide.

5. The method of claim 1, wherein sufficient methylene chloride is utilized in the reaction between bishpenol-A and phosgene to achieve interfacial reaction conditions.

6. The method of claim 1, wherein bisphenol-A is introduced into the reaction vessel by using an extruder.

7. The method of claim 1, wherein bishpenol-A is introduced in the reactor vessel by an auger screw.