Method and apparatus for rapid determination of fries rearrangement products in aromatic polycarbonate resins

Abstract

A rapid analysis method for the determination of Fries rearrangement products in aromatic polycarbonate resins utilizes in-line determination of polymer concentration and in-line fluorescence detection of Fries rearrangement products. The method avoids time consuming sample preparation required by previous methods, allows for separation of interfering low molecular weight components, and is suitable for automation.

What is claimed is:  
     
         1 . A method for analysis of Fries rearrangement products in aromatic polycarbonate resins, comprising: 
 providing an analytical sample comprising an aromatic polycarbonate;    optionally, separating the analytical sample to yield a high molecular weight fraction;    performing an in-line determination of aromatic polycarbonate concentration in the analytical sample; and    performing an in-line determination of the fluorescence signal due to Fries rearrangement products in the analytical sample;    wherein the total analysis time is not greater than about 5 minutes per sample.    
     
     
         2 . The method of  claim 1 , wherein the aromatic polycarbonate is synthesized from at least one dihydric phenol selected from the group consisting of 2,2-bis-(4-hydroxyphenyl)propane; hydroquinone; resorcinol; 2,2-bis-(4-hydroxyphenyl)pentane; 2,4′-dihydroxydiphenylmethane; bis-(2-hydroxyphenyl)methane; bis-(4-hydroxyphenyl)methane; bis-(4-hydroxy-5-nitrophenyl)methane; 1,1-bis-(4-hydroxyphenyl)ethane; 3,3-bis-(4-hydroxyphenyl)pentane; 2,2′-dihydroxydiphenyl; 2,6-dihydroxynapthylene; bis-(4-hydroxyphenyl)sulfone; 2,2′-dihydroxydiphenylsulfone; 4,4′-dihydroxydiphenylether; and 4,4′-dihydroxy-2,5-diethoxydiphenylether.  
     
     
         3 . The method of  claim 1 , wherein the analytical sample comprising aromatic polycarbonate comprises a polymerization reaction mixture.  
     
     
         4 . The method of  claim 1 , wherein separating the analytical sample to yield a high molecular weight fraction comprises the use of size exclusion chromatography or normal phase liquid chromatography.  
     
     
         5 . The method of  claim 1 , wherein the in-line determination of the polymer concentration in the analytical sample utilizes one or more detection methods selected from the group consisting of infrared absorption spectroscopy, ultraviolet absorption spectroscopy, differential refractive index detection, ultrasonic detection, viscometry, and evaporative light scattering detection.  
     
     
         6 . The method of  claim 1 , wherein the fluorescence determination of the concentration of Fries rearrangement products in the analytical sample utilizes an excitation wavelength within about 30 nm of the fluorescence excitation maximum.  
     
     
         7 . The method of  claim 1 , wherein the fluorescence determination of the concentration of Fries rearrangement products in the analytical sample utilizes an excitation wavelength within about 20 nm of the fluorescence excitation maximum.  
     
     
         8 . The method of  claim 1 , wherein the fluorescence determination of the concentration of Fries rearrangement products in the analytical sample utilizes an excitation wavelength within about 10 nm of the fluorescence excitation maximum.  
     
     
         9 . The method of  claim 1 , wherein the fluorescence determination of the concentration of Fries rearrangement products in the analytical sample utilizes an emission wavelength within about 50 nm of the fluorescence emission maximum.  
     
     
         10 . The method of  claim 1 , wherein the fluorescence determination of the concentration of Fries rearrangement products in the analytical sample utilizes an emission wavelength within about 30 nm of the fluorescence emission maximum.  
     
     
         11 . The method of  claim 1 , wherein the fluorescence determination of the concentration of Fries rearrangement products in the analytical sample utilizes an emission wavelength within about 10 nm of the fluorescence emission maximum.  
     
     
         12 . The method of  claim 1 , wherein the total analysis time is not greater than about 3 minutes per sample.  
     
     
         13 . The method of  claim 1 , wherein the total analysis time is not greater than about 90 seconds per sample.  
     
     
         14 . The method of  claim 1 , wherein the total analysis time is not greater than 60 seconds per sample.  
     
     
         15 . The method of  claim 1 , wherein the total analysis time is not greater than 40 seconds per sample.  
     
     
         16 . The method of  claim 1 , wherein the in-line determination of aromatic polycarbonate concentration and the in-line fluorescence determination of the concentration of Fries rearrangement products in the analytical sample are conducted sequentially.  
     
     
         17 . The method of  claim 1 , further comprising preparing at least one analytical sample by dissolving an aromatic polycarbonate resin in a suitable solvent.  
     
     
         18 . The method of  claim 17 , wherein the suitable solvent is selected from the group consisting of benzene, toluene, xylene, chloroform, tetrahydrofuran, methylene chloride, trichloroethylene, dichloroethane, methyl acetate, ethyl acetate, and mixtures comprising at least one of the foregoing solvents.  
     
     
         19 . A method for analysis of Fries rearrangement products in aromatic polycarbonate resins, comprising: 
 providing a plurality of analytical samples each comprising aromatic polycarbonate;    optionally, separating each analytical sample to yield a high molecular weight fraction;    performing an in-line determination of aromatic polycarbonate concentration in each analytical sample; and    performing an in-line determination of the fluorescence signal due to Fries rearrangement products in each analytical sample;    wherein the total analysis time is not greater than about 5 minutes per sample.    
     
     
         20 . The method of  claim 19 , wherein separating each analytical sample to yield a high molecular weight fraction, performing an in-line determination of aromatic polycarbonate concentration in each analytical sample, and performing an in-line determination of the concentration of Fries rearrangement products in each analytical sample using fluorescence spectroscopy are conducted without human intervention.  
     
     
         21 . A method for analysis of Fries rearrangement products in aromatic polycarbonate resins, comprising: 
 providing an analytical sample comprising aromatic polycarbonate synthesized from at least one dihydric phenol comprising bisphenol A;    optionally, separating the analytical sample to yield a high molecular weight fraction;    performing an in-line determination of aromatic polycarbonate concentration in the analytical sample using differential refractive index detection; and    performing an in-line determination of the fluorescence signal due to Fries rearrangement products in the analytical sample using an excitation wavelength of about 280 to about 360 nm and an emission wavelength of about 420 to about 650 nm;    wherein the total analysis time is not greater than about 5 minutes per sample.    
     
     
         22 . A system for analysis of Fries rearrangement products in analytical samples comprising aromatic polycarbonate, comprising: 
 a solvent delivery system;    an autoinjector for injecting a portion of the analytical sample;    optionally, a chromatographic column for separating said analytical sample to yield a aromatic polycarbonate high molecular weight fraction;    an in-line concentration detector for determining the aromatic polycarbonate concentration in the analytical sample;    an in-line fluorescence detector for determining the fluorescence signal due to Fries rearrangement products in each analytical sample;    wherein the system's total analysis time is not greater than 5 minutes per sample.    
     
     
         23 . The system of  claim 22 , further comprising an analytical sample comprising aromatic polycarbonate.  
     
     
         24 . The system of  claim 22 , further comprising a plurality of analytical samples comprising aromatic polycarbonate.  
     
     
         25 . The system of  claim 22 , further comprising a sample preparation module for automatically preparing an analytical sample by dissolving an aromatic polycarbonate resin in a suitable solvent.  
     
     
         26 . The system of  claim 22 , further comprising a computer for calculating the concentration of Fries rearrangement products in the aromatic polycarbonate based on the aromatic polycarbonate concentration in the analytical sample and the concentration of Fries rearrangement products in the analytical sample, and, optionally, for reversibly controlling one or more of the solvent delivery system, the autoinjector, the fluorescence detector, and the concentration detector.  
     
     
         27 . An analysis system, comprising: 
 a sample preparation module for preparing a plurality of analytical samples, each sample being prepared by dissolving an aromatic polycarbonate resin in a suitable solvent.    an autoinjector for injecting a portion of each analytical sample;    a chromatographic column for separating each analytical sample to yield an aromatic polycarbonate high molecular weight fraction;    an in-line concentration detector for determining the aromatic polycarbonate concentration in each analytical sample;    an in-line fluorescence detector for determining the fluorescence signal due to Fries rearrangement products in each analytical sample; and    a computer for calculating the concentration of Fries rearrangement products in the aromatic polycarbonate based on the aromatic polycarbonate concentration in the analytical sample and the concentration of Fries rearrangement products in the analytical sample, and for reversibly controlling the sample preparation module, the solvent delivery system, the autoinjector, the fluorescence detector, and the concentration detector;    wherein the system's total analysis time is not greater than 5 minutes per sample; and wherein computer control of the sample preparation module, the solvent delivery system, the autoinjector, the fluorescence detector, and the concentration detector enables analysis of the plurality of samples without human intervention.