Method for quantitatively analyzing residual phosphorus oxychloride

Abstract

The invention relates to a method for quantitatively analyzing residual phosphorus oxychloride. The method comprises the following steps of: rapidly weighing a phosphorus oxychloride sample and fully hydrolyzing the phosphorus oxychloride sample in chilled brine to form orthophosphoric acid; refrigerating a hydrolyzed sample at the temperature of between 20 below zero and 10 DEG C, and slowly leaching the sample by using filter paper to separate phosphoric acid from an organic acid component; performing color development and color comparison on filtrate, wherein a color developing condition is that: color developing time is between 3 and 5 minutes; color developing temperature is room temperature; and a color developing medium is prepared by adding 8mL HNO3, 25mL 0.04mol / L solution of ammonium molybdate and 12.5mL 0.02mol / L solution of ammonium metavanadate into a 250mL volumetric flask respectively; measuring a light absorption value with a cuvette having an optical path of 1 centimeter by using color developing liquid into which the sample is not added as reference solution at a position of 420 nanometers; and calculating the concentration of discharged phosphorus in comparison to the standard working curve of phosphorus and converting the concentration into the content of the phosphorus oxychloride. The method is simple to operate, rapid and correct, and suitable for analyzing a fire retardant synthesized by using the phosphorus oxychloride as a raw material.

Description

technical field [0001] The invention relates to a method for quantitatively analyzing residual phosphorus oxychloride in a flame retardant bisphenol A bis(diphenyl phosphate) intermediate, which is a spectrophotometric method. Background technique [0002] In the plastics industry, higher requirements are put forward for the fire safety of plastic products, especially in electronics, wires, cables and indoor building materials, which not only require high flame retardancy, but also require halogen-free or pollution-free. Bisphenol A bis(diphenyl phosphate), referred to as BDP, is a colorless viscous liquid. It is an excellent halogen-free flame retardant as an important additive for plastics and has a wide application prospect. [0003] However, in the process of synthesizing BDP, because the residual phosphorus oxychloride in the intermediate can react with phenol, it is not conducive to post-treatment processes such as product purification, which seriously affects product ...

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Problems solved by technology

[0003] However, in the process of synthesizing BDP, because the residual phosphorus oxychloride in the intermediate can react with phenol, it is not conducive to the purification of the product and other post-treatment procedures, which seriously affects the quality of the product.

There was William B. Harold; W. Dirk Krobuka based on bisphenol (diphenyl phosphate) flame retardant [P]. Chinese patent CN1355808 only adopts nuclear magnetic resonance method in the patent, and the intermediate The content of phosphorus oxychloride is determined, but there is no clear and detailed analysis procedure, and there are problems such as the limitation that general laboratories do not have large-scale instruments, and no other analysis methods have been found.

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