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Acid-base indicator and preparation method thereof

The technology of acid-base indicator and phenol derivative is applied in the field of acid-base indicator and its preparation, which can solve the problems of limited application field, partial acidity of discoloration point, instability of bromophenol blue, etc., and achieves stable structure, easy synthesis, The effect of high color sensitivity

Active Publication Date: 2013-07-10
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Patent application CN201110226669.9 discloses the synthesis of a water-soluble bromophenol blue, but the bromophenol blue is unstable, and the discoloration point is slightly acidic, so it is not suitable as an indicator for long-term observation, and the application field is limited
In addition, compounds such as bromophenol blue and bromophenol purple are relatively expensive

Method used

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  • Acid-base indicator and preparation method thereof
  • Acid-base indicator and preparation method thereof
  • Acid-base indicator and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0029] Embodiment 1: a kind of preparation method of acid-base indicator, carry out according to the following steps:

[0030] Pour 35.0mL of 98% sulfuric acid and 11.2mL of fuming nitric acid into the reactor, stir and mix in a water bath at 70°C at a constant temperature. After mixing evenly, raise the temperature of the water bath to 95°C, and add 15.5g of saccharin solids (the solids are added in four times) , after the addition of the solids, heat at a constant temperature for 65 minutes, then stop the reaction, pour the solution into 250 g of crushed ice, stir well, dissolve the ice cubes and filter to obtain 1.1 g of white powder. Add 1.1g of white powder and 1.6g of phenol into the reactor, under the protection of nitrogen, add 1.5mL of fuming tin chloride, and control the temperature between 130-140°C for 7 hours. Add 100mL of 1mol / L HCl solution at 70°C to dissolve tin chloride and excess phenol, dissolve the precipitate obtained after hot filtration with 50mL of 1mo...

Embodiment 2

[0033] Embodiment 2: a kind of acid-base indicator and preparation method thereof, carry out as follows:

[0034] Pour 15.0mL of 98% sulfuric acid and 11.2mL of fuming nitric acid into the reactor, stir and mix in a water bath at 70°C at a constant temperature. After mixing evenly, raise the temperature of the water bath to 95°C, and add 15.5g of saccharin solid (the solid is added in four times) , after the addition of the solids, heat at a constant temperature for 65 minutes, then stop the reaction, pour the solution into 250 g of crushed ice, stir well, and filter after the ice cubes dissolve to obtain 0.8 g of white powder. Add 0.6g of white powder and 1.2g of phenol into the reactor, add 1.3mL of fuming tin chloride under the protection of nitrogen, and control the temperature between 170-180°C for 12h. Add 100mL of 1mol / L HCl solution at 70°C to dissolve tin chloride and excess phenol, dissolve the precipitate obtained after hot filtration with 50mL of 1mol / L NaOH soluti...

Embodiment 3

[0035] Embodiment 3: a kind of acid-base indicator and preparation method thereof, carry out as follows:

[0036] Pour 22.4mL of 98% sulfuric acid and 11.2mL of fuming nitric acid into the reactor, stir and mix in a water bath at 70°C at a constant temperature. After mixing evenly, raise the temperature of the water bath to 95°C, and add 15.5g of saccharin solids (the solids are added in four times) , after adding the solids, heat at constant temperature for 65 minutes, then stop the reaction, pour the solution into 250 g of crushed ice, stir well, and filter after the ice cubes dissolve to obtain 0.1 g of white powder. Add 0.1 g of white powder and 0.5 g of phenol into the reactor, add 0.8 mL of fuming tin chloride under the protection of nitrogen, and control the temperature between 90 and 100° C. for 4 hours. Add 50mL of 1mol / L HCl solution at 70°C to dissolve tin chloride and excess phenol, dissolve the precipitate obtained after hot filtration with 30mL of 1mol / L NaOH sol...

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Abstract

The invention relates to an acid-base indicator having a structural formula as described in the specification and a preparation method thereof. The preparation method is characterized by comprising the following steps: placing a phenol derivative and a product of a reaction of saccharin with a nitration reagent in a reactor; adding fuming tin chloride under the protection of nitrogen; carrying out heating for a reaction; adding an acid solution to dissolve tin chloride and excess phenol derivative after the reaction; carrying out hot filtration to obtain a precipitate; dissolving the obtained precipitate with an NaOH solution with a concentration of 1 mol / L; carrying out filtration and acidifying an obtained filtrate with an acid; and subjecting obtained deposition to recrystallization so as to prepare the acid-base indicator. The acid-base indicator has the characteristics of easy synthesis, an approximately neutral color transition point, sensitive color transition, a stable structure and the like.

Description

technical field [0001] The invention relates to an acid-base indicator and a preparation method thereof, belonging to the technical field of new materials. Background technique [0002] Phenol red and its derivatives are widely used as acid-base indicator, indicator for non-aqueous titration, protein electrophoresis staining and virus assay, etc. As a prominent phenol red derivative, bromophenol blue introduces a bromine atom on the phenol red molecule. The range of color change is yellow when the pH is less than 3.0, and blue-purple when the pH is greater than 4.6. Bromophenol blue and other phenol red derivatives have a wide range of applications. Application prospect, its intermediates can also be used to prepare various functional dyes. [0003] Patent application CN201110226669.9 discloses the synthesis of a water-soluble bromophenol blue, but bromophenol blue is unstable and its color change point is slightly acidic, so it is not suitable as an indicator for long-term...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/80
Inventor 丁玉强单婕王大伟
Owner JIANGNAN UNIV
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