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Method for avoiding carbon dioxide interference in ester hydrolysis reaction and measuring method of ester group equivalents

A technology for measuring carbon dioxide, which is applied in the direction of chemical analysis by titration method, can solve the problems of not mentioning carbon dioxide to hydroxide, increasing the cost of manpower and material resources, and the reaction is not easy to control, so as to achieve complete hydrolysis and avoid side reactions , the effect of avoiding contact

Inactive Publication Date: 2019-03-26
GUANGDONG SHENGYI SCI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although isopropanol was successfully prepared, it did not mention how to avoid the influence of carbon dioxide in the air on hydroxide
[0018] When avoiding the problem of carbon dioxide or water interfering with the reaction system, the usual method is to control the reaction system to a vacuum condition or pass an inert gas into the reaction system. In a reaction environment with a high degree of vacuum, the boiling point of water is low. , it will make the reaction difficult to control, and the method of controlling the reaction conditions of the vacuum degree is more complicated in the large-scale industrial production process, which will increase the cost of manpower and material resources, and the method of always passing the inert gas in the reaction system is also difficult to be used in large-scale production. Used in large-scale application production

Method used

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  • Method for avoiding carbon dioxide interference in ester hydrolysis reaction and measuring method of ester group equivalents
  • Method for avoiding carbon dioxide interference in ester hydrolysis reaction and measuring method of ester group equivalents
  • Method for avoiding carbon dioxide interference in ester hydrolysis reaction and measuring method of ester group equivalents

Examples

Experimental program
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Effect test

Embodiment 1

[0061] A kind of assay method of active ester (Japanese DIC production, HPC-8000) ester group equivalent is as follows:

[0062] (1) Prepare a sodium hydroxide aqueous solution with a concentration of about 1.0mol / L; take about 0.20-0.80g of the active ester sample after drying, accurately weigh and record the weight, accurate to four decimal places, and the unit is g; Put the ester sample into a flat-bottomed flask, slowly put it into an electromagnetic stirrer, pipette 5ml of NaOH aqueous solution into the flask with a pipette gun, then add 30mL of pure water and 0.5mL of toluene. Then connect the flat-bottomed flask to a condensing reflux device, start heating, heat to boiling under electromagnetic stirring, and keep boiling and reflux for 20 minutes, then stop heating.

[0063] (2) After cooling to room temperature, rinse the condenser tube with about 20mL of pure water from the top of the condenser tube to obtain a clear and transparent mixed solution, which is to be titr...

Embodiment 2

[0079] A kind of assay method of the ester group equivalent of diphenyl isophthalate, as follows:

[0080] (1) Prepare an aqueous sodium hydroxide solution with a concentration of about 1.0mol / L; get about 0.25-0.30 g of a sample of diphenyl isophthalate after drying, accurately weigh and record the weight, accurate to four decimal places, The unit is g; put the sample into a flat-bottomed flask, slowly put it into an electromagnetic stirrer, pipette 5mL of NaOH aqueous solution into the flask, then add 30mL of pure water and 0.5mL of toluene. Then connect the flat-bottomed flask to a condensing reflux device, start heating, heat to boiling under electromagnetic stirring, and keep boiling and reflux for 30 minutes, then stop heating.

[0081] (2) After cooling to room temperature, rinse the condenser tube with about 20mL of pure water from the top of the condenser tube to obtain a clear and transparent mixed solution, which is to be titrated; use hydrochloric acid ethanol solu...

Embodiment 3

[0096] The only difference with Example 2 is that in this example, toluene is replaced by xylene (containing about 40% m-xylene, about 20% o-xylene, about 20% p-xylene, about 20% ethylbenzene ).

[0097] Two experiments were carried out in parallel, and the results are shown in Table 5.

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Abstract

The invention provides a method for avoiding carbon dioxide interference in an ester hydrolysis reaction and a measuring method of ester group equivalents. The method comprises the following steps that (1) an alkaline aqueous solution and an ester compound are mixed, then an organic reagent is added, the organic reagent forms an organic reagent film on the surface of the alkaline aqueous solution,and the ester hydrolysis reaction is conducted, wherein the density of the organic reagent is less than that of water, the organic reagent and the water are mutually insoluble, and meanwhile the organic reagent is not subjected to a chemical reaction in the ester hydrolysis reaction process. According to the method for avoiding carbon dioxide interference in the ester hydrolysis reaction and themeasuring method of the ester group equivalents, the organic reagent which is less than the water in density and mutually insoluble with the water is adopted to form the organic reagent film on the surface of the aqueous solution, thus contact between air and hydrolysate can be avoided, consumption of hydroxide by carbon dioxide in the air is avoided accordingly, the situation that the carbon dioxide and the hydroxide react to generate carbonate impurities is also avoided, therefore, the measuring accuracy of the content of ester groups in the ester compound can be significantly increased, anda side reaction in the hydrolysis process is avoided.

Description

technical field [0001] The invention belongs to the technical field of ester hydrolysis control and application, and relates to a method for avoiding carbon dioxide interference in ester hydrolysis reaction and a method for measuring ester group equivalent. Background technique [0002] The hydrolysis reaction of esters has a wide range of industrial applications, such as the production of isopropanol, ethylene glycol, etc. through the hydrolysis of esters. In addition, through the hydrolysis reaction of ester, it can also be used for the determination of oil saponification value. [0003] In industrial production, esters are mostly hydrolyzed under alkaline conditions (sodium hydroxide / potassium hydroxide). But, in the hydrolysis reaction process, sodium hydroxide, potassium hydroxide are easily affected by carbon dioxide in the air, and side reactions (such as reaction formula I and reaction formula II) take place to generate sodium carbonate or salt of wormwood impurity,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N31/16
CPCG01N31/16
Inventor 盘文辉王小兵
Owner GUANGDONG SHENGYI SCI TECH