Mixed indicator method for determination of content of polyglycerol in glycerol

Abstract

The invention provides a mixed indicator method for determination of the content of polyglycerol in glycerol. The method comprises the following steps: determining the content of total glycerol by using a potassium dichromate process wherein the content of total glycerol includes the total amount of polyglycerol and free glycerol; then determining the content of free glycerol by using a formic acid process; and calculating difference between the content of total glycerol and the content of free glycerol so as to obtain the content of polyglycerol. The method provided by the invention can carry out rapid and accurate determination on the content of polyglycerol in glycerol and has the advantages of high sensitivity, high result accuracy and a wide detection scope; and compared with an original indicator (methyl red) employed in conventional analytical methods, a mixed indicator (which is composed of an ethanol solution of neutral red with a concentration of 0.1% and an ethanol solution of bromothymol blue with a concentration of 0.1% in a volume ratio of 1: 1) used in the invention has a more accurate and sensitive titration end point and produces more reliable results.

Description

technical field [0001] The invention relates to a method for determining the content of polymerized glycerol in glycerin by the mixed indicator method, in particular to a method for determining the content of polymerized glycerol in glycerin by the mixed indicator method. Background technique [0002] In recent years, with the increasing strictness of the world's fuel oil standards and the promulgation of the new environmental protection law, the requirements for environmental protection are getting higher and higher, which puts forward higher requirements for the quality of diesel for vehicles. Although people remove sulfur and aromatics by refining diesel oil, they also remove the natural components with anti-wear function in diesel oil, resulting in the higher the degree of diesel oil refining, the worse the lubricity. Therefore, the development of high-efficiency diesel anti-wear agent to improve the lubricity of low sulfur diesel oil. Research at home and abroad has fo...

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Problems solved by technology

[0004] The object of the present invention is to provide a method for measuring the content of polymerized glycerol in glycerin by a mixed indicator method, which solves the problem of gradual color change and inconspicuous jumps when titration is used to measure the content of polymerized glycerol in glycerin, and the color change range of indicator pH Improper, easy to cause high measurement results

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