CS256487B1 - A method for the simultaneous quantitative determination of by-products and phenol in dian - Google Patents

Abstract

The solution concerns a method for simultaneous quantitative determination of by-products and phenol in diane by capillary gas chromatography with dosing directly onto the column. The analysis does not require preparation of derivatives or independent determination of phenol and is performed with high separation efficiency. A column made of very pure silica, wetted with phenylmethyl silicone oil, is preferably used for the analysis. The analysis time is 25 minutes. The method is suitable for assessing the quality of diane for epoxy resins and polycarbonates.

Description

The invention relates to the quantitative determination of by-products and phenol in diene by a gas chromatography method.

2,2-bis- (4-hydroxyphenyl) -propane called dian or Bisphenol A is mainly used for the production of paints and resins based on polycarbonates. Acid catalyzed condensation of phenol and acetone is produced. In addition to the desired product, β, β-dian, some by-products are formed, in particular 4-methyl-4- (p-hydroxyphenyl) -pentanone-2,2,2- (2-hydroxyphenyl) -propane called οτθ-dian, 2- (4- hydroxyphenyl) -2- (2-hydroxyphenyl) -propane called oadian, 4- (4-hydroxyphenyl) -2,2,4-trimethylchroman called codimer, 1,1,3-trimethyl-3- (4-hydroxyphenyl) -indanol-5,

2,4-bis- (4-hydroxycoumyl) -phenol called BPX, optionally other substances such as p-isopropenylphenol, 2-hydroxy-2,4,4-trimethylphavanate, 4-methyl-2,4-bis- (4 In terms of further processing, the content of by-products and residual phenol is undesirable and is therefore monitored analytically.

Initially, by-products in the diane were analyzed semi-quantitatively by paper or thin-layer chromatography, later methods using gas or liquid chromatography were published. Phenyl was determined by gas chromatography either by a separate method or together with dihydroxy derivatives. Only dihydroxy derivatives could be subjected to the direct gas chromatographic determination, so the dianne was later derivatized. The samples were converted to acatates or trlmethylsilyl ethers by some of the silylating agents, eg N, O-bis- (trimethylsilyl) -trifluoroeacetamide, the derivatives were separated after evaporation in injectors separated

256 487 on packed column and detected by flame ionisation detector · In this way all by-products but not phenol could be determined ·

We have now found a method for the simultaneous quantitative determination of byproducts and phenol in diane by the gas chromatography method of the present invention, which is to dispense a solution of diane in ethanol at the beginning of a glass or silica capillary column wetted with a stationary phase of silicone oil type. or polyglycol at a temperature of 40 ^U C to solvent boiling point by direct dispensing onto the column ·

The dianne solution without prior derivatization is injected into the top of the capillary column via a syringe and chromatographed at programmed column temperature, detected by a flame ionization detector, and the components determined after correcting the detector responses by calibration factors determined by analysis of a mixture of known composition. For wetting of the capillary column, a stationary phase of silicone oil or polyglycol type is used, which are bound physically or chemically to the inner surface of the column or they are reinforced by chemical bonding ·

The simultaneous determination of byproducts and phenol in the diane according to the invention represents the saving of the eilylating agent used for the derivatization of dian and the time required for the preparation of the diane derivatives. working on a capillary column, which shows high efficiency and ethanated substances are well eeparable,

The analysis example according to the invention is illustrated by the following example:

Example 1

Diane solution in ethanol ee is dosed with a Hamilton syringe to the top of the silica capillary column maintained at 40-78 ° C. · Use a very pure capillary column.

- 3 256 487 silicon dioxide with a length of 25 m and an internal diameter of 0,32 mm covered with a stationary phase, eg phenylmethylsilicone oil. The column is placed in a gas chromatograph thermostat equipped with a metering device, eg a flame ionization detector and an evaluation device. The thermostat of the chromatograph is rapidly heated to an initial operating temperature of 210 ° C and then rises for 6 minutes at a rate of 5 ° C / min and at a rate of 10 ° C / min to 300 ° C. The helium carrier gas flows at 3 ml / min. The analysis is complete within 25 minutes. The responses of the individual components are corrected by the factors obtained by evaluating the analysis of the calibration mixture solution weighed from pure standards. From the corrected response values, the composition of the analyzed Diana is calculated by the internal normalization method.

Claims (1)

Method for simultaneous quantitative determination of by-products and phenol in dianu by gas chromatography method, characterized in that the solution of dianu in ethanol is dosed at the beginning of a glass or quartz capillary column wetted by a stationary phase of silicone oil or polyglycol type at 40 ° C to the boiling point of solvent by direct column loading.