阅读说明：本技术 一种利用香草醛制备的酸碱指示剂及其合成方法 (acid-base indicator prepared from vanillin and synthesis method thereof ) 是由 张海涛 魏康 杨雅茹 曲建波 王建勇 于 2019-08-28 设计创作，主要内容包括：本发明提供一种利用香草醛制备的酸碱指示剂及其合成方法,所述酸碱指示剂在酸性环境中显示黄色,在碱性环境中显示深红色,显色范围为pH≥8.0。所述酸碱指示剂易合成,稳定性好,显色清晰,指示灵敏度与酚酞相当,具有很好的实用性。(the invention provides an acid-base indicator prepared by utilizing vanillin and a synthesis method thereof, wherein the acid-base indicator shows yellow color in an acidic environment, shows deep red color in an alkaline environment, and has the color development range of pH more than or equal to 8.0. The acid-base indicator is easy to synthesize, good in stability, clear in color development, equivalent to phenolphthalein in indicating sensitivity and good in practicability.)

1. An acid-base indicator prepared by utilizing vanillin, which is characterized in that: the structural formula of the acid-base indicator is as follows:

。

2. The acid-base indicator prepared by using vanillin as claimed in claim 1, wherein: the acid-base indicator shows yellow in an acid environment, shows dark red in an alkaline environment, and has the color development range of pH more than or equal to 8.0.

3. the method of claim 1, wherein the method comprises the following steps: the adopted raw materials comprise vanillin, 4-bromo-1, 8-naphthalic anhydride, 6-chloro-1-hexanol and hydrazine hydrate; the synthesis method comprises the steps of preparing N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide, preparing N- (2-hydroxyethyl) -4-hydrazine-1, 8-naphthalimide, preparing tetramer 6-chloro-1-hexanol vanillin and preparing the product.

4. The method of claim 1, wherein the method comprises the following steps: the preparation method comprises the following steps of (1) preparing N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide: reacting 4-bromo-1, 8-naphthalic anhydride with ethanolamine according to a molar ratio of 1:4, wherein the reaction temperature is 80 +/-5 ℃, and the reaction time is 2 +/-0.5 h; a pale red solid was obtained.

5. The method of claim 4, wherein the method comprises the following steps: the preparation method comprises the following steps of (1) preparing N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide: dissolving the obtained light red solid by using dichloromethane, adding 200-mesh silica gel powder with 300 meshes for sample mixing, performing rotary evaporation to obtain powdery solid, and purifying by using a silica gel column to obtain a pure white solid product N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide.

6. The method of claim 3, wherein the method comprises the following steps: the preparation method comprises the following steps of (1) preparing N- (2-hydroxyethyl) -4-hydrazine-1, 8-naphthalimide: the compound is prepared by reacting N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide with hydrazine hydrate, wherein the reaction temperature is 70 +/-5 ℃, and the reaction time is 3.5 +/-0.5 h; an orange-yellow product is obtained.

7. the method of claim 3, wherein the method comprises the following steps: the preparation of the tetramer 6-chloro-1-hexanol vanillin comprises the following steps: reacting vanillin with 6-chloro-1-hexanol in N, N-dimethylformamide at 80 + -5 deg.C for 24 + -0.5 h.

8. The method of claim 3, wherein the method comprises the following steps: the preparation of the tetramer 6-chloro-1-hexanol vanillin comprises the following steps: adding ethyl acetate into the reaction liquid after the reaction, extracting, reserving an upper yellow ethyl acetate phase, and drying to obtain yellow viscous liquid.

9. The method of claim 3, wherein the method comprises the following steps: the preparation of the tetramer 6-chloro-1-hexanol vanillin comprises the following steps: dissolving the yellow viscous liquid with dichloromethane, adding silica gel powder, stirring, rotary evaporating to obtain yellow powdery solid, and purifying with silica gel column to obtain pure yellow viscous liquid tetramer 6-chloro-1-hexanol vanillin.

10. The method of claim 3, wherein the method comprises the following steps: the prepared product is as follows: reacting N- (2-hydroxyethyl) -4-hydrazine-1, 8-naphthalimide and tetramer 6-chloro-1-hexanol vanillin according to a molar ratio of 1:1, wherein the reaction temperature is 80 ℃, and the reaction time is 8 hours, so as to obtain red powder precipitate; and precipitating the red powder, removing water and purifying to obtain the product 2- (2-hydroxyethyl) -6- (2- (4- ((6-hydroxyhexyl) oxy) -3-methoxybenzylidene) hydrazino) -1H-benzo [ de ] isoquinoline-1, 3 (2H) -diketone.

Technical Field

The invention belongs to the technical field of synthesis of acid-base indicators, and particularly relates to an acid-base indicator prepared by utilizing vanillin and a synthesis method thereof.

Background

Vanillin, also known as vanillin, contains aldehyde group and phenolic hydroxyl group, can perform various reactions such as substitution, condensation and the like, has thick milk flavor, is easily soluble in ethanol, glacial acetic acid, chloroform, pyridine, ether and carbon disulfide, is also soluble in oil and strong alkali solution, is one of the most widely applied perfume substances in the world, and is widely applied to various industries such as food, medicine, tobacco, daily chemicals, cosmetics and the like.

4-bromo-1, 8-naphthalic anhydride is slightly dissolved in glacial acetic acid, chlorobenzene, DMF, ethylene glycol, methyl ether and the like, is used for synthesizing important raw materials of perylene dyes, pigments and fluorescent whitening agents, and is used for preparing dyes such as fluorescent yellow, fluorescent orange and the like.

The acid-base indicator is a very useful chemical reagent, and currently, the types of phenolphthalein, nitrophenol, sulfophenolphthalein, azo compounds and the like are mainly used, wherein phenolphthalein is the most popular acid-base indicator. But the phenolphthalein has an insignificant color change, and is pink and light when alkaline. The current scientific and technological literature does not have reports of using vanillin to prepare the acid-base indicator, however, the invention successfully synthesizes a novel acid-base indicator by using vanillin, 4-bromo-1, 8-naphthalic anhydride and the like as raw materials, and the indicator has the advantages of easy synthesis, good stability, clear color development, equivalent indicating effect to phenolphthalein and the like.

Disclosure of Invention

The invention aims to provide an acid-base indicator prepared by utilizing vanillin, which has the advantages of easy synthesis, good stability, clear color development and indication sensitivity equivalent to phenolphthalein. The invention also aims to provide a synthesis method of the acid-base indicator.

In order to achieve the purpose, the invention adopts the technical scheme that:

An acid-base indicator prepared by utilizing vanillin, which is characterized in that: the structural formula of the acid-base indicator is as follows:

。

the acid-base indicator shows yellow in an acid environment, shows dark red in an alkaline environment, and has the color development range of pH more than or equal to 8.0.

the adopted raw materials comprise vanillin, 4-bromo-1, 8-naphthalic anhydride, 6-chloro-1-hexanol and hydrazine hydrate; the synthesis method comprises the steps of preparing N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide, preparing N- (2-hydroxyethyl) -4-hydrazine-1, 8-naphthalimide, preparing tetramer 6-chloro-1-hexanol vanillin and preparing the product.

The preparation method comprises the following steps of (1) preparing N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide: reacting 4-bromo-1, 8-naphthalic anhydride with ethanolamine according to a molar ratio of 1:4, wherein the reaction temperature is 80 +/-5 ℃, and the reaction time is 2 +/-0.5 h; a pale red solid was obtained.

The preparation method comprises the following steps of (1) preparing N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide: dissolving the obtained light red solid by using dichloromethane, adding 200-mesh silica gel powder with 300 meshes for sample mixing, performing rotary evaporation to obtain powdery solid, and purifying by using a silica gel column to obtain a pure white solid product N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide.

The preparation method comprises the following steps of (1) preparing N- (2-hydroxyethyl) -4-hydrazine-1, 8-naphthalimide: the compound is prepared by reacting N- (2-hydroxyethyl) -4-bromo-1, 8-naphthalimide with hydrazine hydrate, wherein the reaction temperature is 70 +/-5 ℃, and the reaction time is 3.5 +/-0.5 h; an orange-yellow product is obtained.

The preparation of the tetramer 6-chloro-1-hexanol vanillin comprises the following steps: reacting vanillin with 6-chloro-1-hexanol in N, N-dimethylformamide at 80 + -5 deg.C for 24 + -0.5 h.

The preparation of the tetramer 6-chloro-1-hexanol vanillin comprises the following steps: adding ethyl acetate into the reaction liquid after the reaction, extracting, reserving an upper yellow ethyl acetate phase, and drying to obtain yellow viscous liquid.

The preparation of the tetramer 6-chloro-1-hexanol vanillin comprises the following steps: dissolving the yellow viscous liquid with dichloromethane, adding silica gel powder, stirring, rotary evaporating to obtain yellow powdery solid, and purifying with silica gel column to obtain pure yellow viscous liquid tetramer 6-chloro-1-hexanol vanillin.

The prepared product is as follows: reacting N- (2-hydroxyethyl) -4-hydrazine-1, 8-naphthalimide and tetramer 6-chloro-1-hexanol vanillin according to a molar ratio of 1:1, wherein the reaction temperature is 80 ℃, and the reaction time is 8 hours, so as to obtain red powder precipitate; and precipitating the red powder, removing water and purifying to obtain the product 2- (2-hydroxyethyl) -6- (2- (4- ((6-hydroxyhexyl) oxy) -3-methoxybenzylidene) hydrazino) -1H-benzo [ de ] isoquinoline-1, 3 (2H) -diketone. The reaction formula of the synthesis method is as follows:

Has the advantages that:

(1) the acid-base indicator prepared by utilizing vanillin shows yellow in an acid environment, red in an alkaline environment, obvious color change and large color difference change;

(2) The acid-base indicator prepared by utilizing the vanillin is easy to synthesize, good in stability, clear in color development and equivalent to phenolphthalein in indication sensitivity.

Detailed Description

The present invention is described in detail below with reference to specific examples, which are intended to be purely exemplary and are not intended to limit the invention.