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A kind of acid-base indicator and its preparation method and application

A technology of acid-base indicator and preparation steps, which is applied in material analysis through observation of the influence on chemical indicators, analysis through chemical reaction of materials, organic chemistry, etc., to achieve simple synthesis, good stability, and color development sensitive effect

Active Publication Date: 2021-03-30
SHANXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Therefore, there are certain limitations

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  • A kind of acid-base indicator and its preparation method and application
  • A kind of acid-base indicator and its preparation method and application
  • A kind of acid-base indicator and its preparation method and application

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Embodiment 1

[0025] The preparation of embodiment 1 thymol phthalein

[0026] Mix 2.0mmol thymolphthalein and 2.0mmol urotropine (HMTA) into a 50ml three-neck flask, add 10ml (0.15mol) trifluoroacetic acid (TFA) under ice-bath conditions, and stir the solution for 30min before warming up to room temperature. Continue to heat the oil bath to 72°C for reflux reaction for 24h. After the reaction is stopped, excess TFA is removed by rotary evaporation. Add 50ml H 2 O, the stirred solution was heated to 60°C, filtered after 30 min, and dried to obtain a solid. The solid was further separated by column chromatography, using petroleum ether and dichloromethane at a ratio of 1:3 (v / v) as a developer, and finally dried by rotary evaporation to obtain a light yellow powder.

Embodiment 2

[0027] The preparation of embodiment 2 thymol phthalein

[0028] Mix 1.5mmol thymolphthalein and 2.0mmol urotropine (HMTA) into a 50ml three-neck flask, add 15ml (0.2mol) trifluoroacetic acid (TFA) under ice-bath conditions, and stir the solution for 30min before warming up to room temperature. Continue to heat the oil bath to 72°C for reflux reaction for 8h. After the reaction is stopped, excess TFA is removed by rotary evaporation. Add 30ml H 2 O, the stirred solution was heated to 60°C, filtered after 30 min, and dried to obtain a solid. The solid was further separated by column chromatography, using petroleum ether and dichloromethane at a ratio of 1:3 (v / v) as a developer, and finally dried by rotary evaporation to obtain a light yellow powder.

Embodiment 3

[0029] The preparation of embodiment 3 thymol phthalein

[0030] Mix 1.5mmol thymolphthalein and 1.0mmol urotropine (HMTA) into a 50ml three-necked flask, add 15ml (0.2mol) trifluoroacetic acid (TFA) under ice-bath conditions, and stir the solution for 30min before warming up to room temperature. Continue to heat the oil bath to 72° C. for reflux reaction for 12 h. After the reaction is stopped, excess TFA is removed by rotary evaporation. Add 50ml H 2 O, the stirred solution was heated to 60°C, filtered after 30 min, and dried to obtain a solid. The solid was further separated by column chromatography, using petroleum ether and dichloromethane at a ratio of 1:3 (v / v) as a developer, and finally dried by rotary evaporation to obtain a light yellow powder.

[0031] figure 1 is the color change of thymol phthalein in buffer solution at pH 1-14 (from left to right). figure 2 It is the color change diagram of thymol phthalein in pH buffer solution of 10.0, 10.2, 10.4, 10.6, 1...

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Abstract

The invention provides an acid-base indicator named thymolphthalein aldehyde. A preparation method of that acid-base indicator comprises the following steps: 1) mixing 1.5-2.0 mmol of thymolphthaleinand 1.0-2.0 mmol of urotropine (HMTA) and adding the mixture to a 50ml three-neck bottle, adding 0.15-0.20 mol (10-15 ml) of trifluoroacetic acid under the ice-bath condition, stirring the solution for 30 min and then heating the solution to room temperature; 2) continuing oil bath heating to 72 DEG C for reflux reaction for 8-24 hours, stopping the reaction, and removing excess trifluoroacetic acid by rotary evaporation; 3) adding an appropriate amount of H2O, stirring the solution, heating the solution to 60 DEG C, performing filtering after 30 min, performing drying to obtain a solid, and further separating the solid by column chromatography to obtain faint yellow powder. The indicator is easy to synthesize, stable in structure and sensitive in color change, and the PH color change is in a range of 10.8-12.0.

Description

technical field [0001] The invention relates to an acid-base indicator, in particular to a phenolphthalein-based acid-base indicator and a preparation method and application thereof. Background technique [0002] Acid-base indicators are commonly used chemical reagents, among which phenolphthalein indicators are the most widely used acid-base indicators in reality. Phenolphthalein is one of the earliest acid-base indicators discovered, and thymephenolphthalein is an acid-base indicator with a structure similar to phenolphthalein. Its pH discoloration range is 9.4-10.6, and the color changes from colorless to blue, and the pH of the solution with pH greater than 10.6 cannot be distinguished. Therefore, it has certain limitations. [0003] Thymolphthalein has multiple benzene rings, and its structure can be changed through various reactions such as substitution, oxidation, and isomerization on the benzene rings, thereby expanding new properties and applications. The present...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D307/885G01N21/80C09B11/08
CPCC07D307/885C09B11/08G01N21/80
Inventor 丁媛媛侯玲杰孔祥宇范珍珍郭谨昌董川双少敏
Owner SHANXI UNIV
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