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Preparation method of fluorescein sodium

A technology of sodium fluorescent yellow and fluorescent yellow, applied in the field of chemical analysis reagents, can solve the problems of undiscovered patent publications, etc., and achieve the effects of short preparation period, sharp discoloration, and convenient and simple preparation method.

Inactive Publication Date: 2013-09-11
TIANJIN CHEM REAGENT RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Through the search, no patent publications related to the patent application of the present invention have been found

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A preparation method of fluorescent yellow sodium, the steps are as follows:

[0029] ⑴ Preparation of fluorescent yellow:

[0030] ①Mix 11kg of resorcinol and 7.4kg of phthalic anhydride. After melting at 150°C, add 5g of powdered anhydrous zinc chloride under constant stirring, and start the reaction when the temperature rises to 170-185°C. Stir for half an hour to dissolve completely, and gradually raise the temperature to 210-220°C and keep it warm for 4 hours. The substance begins to thicken and solidifies after cooling. Crush the solidified substance and add hot water to boil for 2 hours to remove residual zinc chloride and m-benzene Diphenol, filter the precipitate with a Buchner funnel, wash and dry to obtain crude fluorescent yellow;

[0031] ② Dissolve 16kg of crude product in 50L of 5% sodium carbonate aqueous solution, heat to dissolve, decolorize with activated carbon and filter, neutralize the filtrate to pH 2-3 with dilute hydrochloric acid, precipitate ...

Embodiment 2

[0035] A preparation method of fluorescent yellow sodium, the steps are as follows:

[0036] ⑴ Preparation of fluorescent yellow:

[0037] ①Mix 11kg of resorcinol and 7kg of phthalic anhydride. After melting at 150°C, add 5g of powdered anhydrous zinc chloride under continuous stirring. When the temperature rises to 170-185°C, the reaction starts. Stir Dissolve completely in half an hour, and gradually raise the temperature to 210-220°C and keep it warm for 4 hours. The substance begins to thicken and solidifies after cooling. Crush the solidified substance and add hot water to boil for 2 hours to remove residual zinc chloride and isophthalic acid. Phenol, filtered the precipitate with a Buchner funnel, washed with water and dried to obtain crude fluorescent yellow;

[0038] ② Dissolve 16kg of crude product in 60L of 5% sodium carbonate aqueous solution, heat to dissolve, decolorize with activated carbon and filter, neutralize the filtrate to pH 2-3 with dilute hydrochloric a...

Embodiment 3

[0042] A preparation method of fluorescent yellow sodium, the steps are as follows:

[0043] ⑴ Preparation of fluorescent yellow:

[0044] ①Mix 11kg of resorcinol and 8kg of phthalic anhydride. After melting at 150°C, add 5g of powdered anhydrous zinc chloride under constant stirring. When the temperature rises to 170-185°C, the reaction starts. Stir Dissolve completely in half an hour, and gradually raise the temperature to 210-220°C and keep it warm for 4 hours. The substance begins to thicken and solidifies after cooling. Crush the solidified substance and add hot water to boil for 2 hours to remove residual zinc chloride and isophthalic acid. Phenol, filtered the precipitate with a Buchner funnel, washed with water and dried to obtain crude fluorescent yellow;

[0045] ②Dissolve 16kg of crude product in 40L of 5% sodium carbonate aqueous solution, heat to dissolve, decolorize with activated carbon and filter, neutralize the filtrate to pH 2-3 with dilute hydrochloric acid...

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PUM

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Abstract

The invention relates to a preparation method of fluorescein sodium. The method comprises the following steps of: mixing resorcinol with phthalic anhydride; melting by rising the temperature to 150 DEG C; adding anhydrous zinc chloride in a stirring manner; performing a reaction under the condition that the temperature is risen to 170 to 185 DEG C; stirring for 0.5 hour; preserving the temperature for 4 hours under the condition that the temperature is risen to 210 to 220 DEG C; solidifying after cooling; crushing a solidified product, adding the crushed product into water and boiling for 2 hours; filtering, washing in the water and drying, thereby obtaining crude fluorescein; dissolving the crude fluorescein into a sodium carbonate water solution; heating and dissolving; decoloring and filtering; neutralizing a filtrate by using diluted hydrochloric acid until the pH value is 2 to 3; separating crystals out, filtering, washing and drying at the temperature of 80 DEG C, thereby obtaining the fluorescein; recrystallizing the fluorescein by using methyl alcohol; drying the obtained crystals at the temperature of 150 to 160 DEG C; weighing the fluorescein, the sodium carbonate and the water; mixing and dissolving the weighed materials; and evaporating until drying, thereby obtaining the fluorescein sodium. The method is simple, general, easy to implement, short in preparation period, simple and convenient to operate and high in fluorescein sodium yield, and raw materials are easy to obtain. Thus, the production cost of an enterprise is lowered while the economic benefit is increased.

Description

technical field [0001] The invention belongs to the field of chemical analysis reagents, and relates to an acid-base indicator, in particular to a preparation method of fluorescent yellow sodium. Background technique [0002] Acid-base indicators are usually only a class of substances that are accompanied by color changes as the pH of the solution changes. It is an indispensable chemical in the field of chemical analysis. This indicative change is actually the result of a "tautomer" structural change. [0003] This tautomer has the properties of a conjugate acid-base pair, which are in a state of equilibrium with each other. When the pH value changes, their balance will be affected, and the balance will be shifted and accompanied by structural changes, and there will be acidic or basic interconversions that lose or gain protons. The indicator at this time is that we study the pH indicator. [0004] In practical applications, it is generally desirable that the color change...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D493/10
Inventor 石开丁
Owner TIANJIN CHEM REAGENT RES INST
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