CN102267976A - Preparation method for m-cresol purple - Google Patents
Preparation method for m-cresol purple Download PDFInfo
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- CN102267976A CN102267976A CN2011102266805A CN201110226680A CN102267976A CN 102267976 A CN102267976 A CN 102267976A CN 2011102266805 A CN2011102266805 A CN 2011102266805A CN 201110226680 A CN201110226680 A CN 201110226680A CN 102267976 A CN102267976 A CN 102267976A
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Abstract
The invention relates to a preparation method for m-cresol purple. The method comprises the following steps of: (1) undergoing a condensation reaction: stirring and heating 300 ml of dried m-cresol and 285 grams of benzene methane sulfonic acid anhydride for 0.5-1 hour, controlling the temperature between 100 DEG C and 105 DEG C, adding 120 mL of phosphorus oxychloride and 120 grams of absolute zinc chloride in certain times when the temperature is lowered to 90-100 DEG C, and stirring for 6-8 hours at constant temperature; and (2) refining: adding 300 mL of water into the reaction product obtained in the step (1), heating to 70-80 DEG C, slowly adding industrial sodium carbonate, heating for 5-6 hours, standing, filtering, neutralizing the filtrate with hydrochloric acid in the ratio 1:1 till the pH is 1-2, standing for removing a viscous substance on a lower layer, and heating for removing m-cresol to obtain 350 grams of finished m-cresol purple. An indicating agent prepared with the method has a narrow color change interval, acute color change, high purity and a small quantity of impurities; and the method is easy to operate, and is suitable for industrial application.
Description
Technical field
The invention belongs to the chemical indicator field, be specifically related to a kind of preparation method of m-cresol purple.
Background technology
Acid base indicator typically refers to a class material that is accompanied by colour-change along with the change of pH value of solution value.Be the indispensable chemical substance of chemical analysis field, this tell-tale variation is actual to be the result of a kind of " tautomer " structural changes.
This tautomer has the character of conjugate acid-base pair, is in a kind of equilibrium state each other.The pH value just can influence their balance when changing, balance moves and be attended by the change of structure, the mutual conversion of the acid or the alkali formula of proton occurred losing or obtaining.The indicator of this moment is the pH indicator of our research just.In actual applications, wish that usually the color change interval of indicator is narrower good, even pH value of solution has less variation also can make indicator produce sharp variation like this.
In order to improve the sharp degree of indicator, what research made new advances forms complexing and produces the indicator of colour-change weak acid and weak base and some specific trace metal ion, becomes the emphasis of our research.
M-cresol purple, molecular formula: C
21H
18O
5S, molecular weight: 382.044, green or brick-red powder is slightly soluble in water and ethanol.Its basic solution is a purple, the little yellow of its weakly acidic solution, and strongly acidic solution is red, variation range pH:1.2～2.8 (red～Huang); PH:7.6～9.2 (Huang～purple).
Summary of the invention
The preparation method who the purpose of this invention is to provide a kind of m-cresol purple.
The technical scheme that realizes the object of the invention is as follows:
A kind of preparation method of m-cresol purple comprises the steps:
(1) condensation reaction: 300 milliliters of meta-cresols of exsiccant and 285 are restrained benzene methanesulfonic acid acid anhydride stirring heating 0.5～1 hour, temperature is controlled at 100～105 ℃, treat to add several times when temperature is cooled to 90～100 ℃ 120 milliliters of phosphorus oxychloride and 120 gram Zinc Chloride Anhydrouss, control and stirred under this temperature 6～8 hours;
(2) refining: as in the reaction product that step (1) obtains, to add 300 milliliters in water, be heated to 70～80 ℃, slowly add industrial sodium carbonate, heated 5～6 hours, and left standstill, filter, filtrate is neutralized to pH 1～2 with 1: 1 hydrochloric acid, leave standstill the thick thing of sub-cloud, add the heat extraction meta-cresol, get finishing room cresol purple.
And, described step (1) is: get the pure benzene methanesulfonic acid acid anhydride of 285 grams, 300 milliliters of meta-cresols, 120 gram Zinc Chloride Anhydrous and 120 milliliters of phosphorus oxychloride under agitation heat under 95～100 ℃ of conditions, continue to be warming up to 110～115 ℃, and be incubated 45～50 minutes, after 300 milliliters of hot-water cure, go out excessive meta-cresol with wet distillation, filter, get the crude product m-cresol purple after the drying.
And described step (2) is: with the crude product m-cresol purple butanols recrystallization that step (1) obtains, purify with ethanol again, or dissolve with sodium hydrogen carbonate solution, and purify with dilute hydrochloric acid precipitated.
Advantage of the present invention and beneficial effect:
The color range of indicator of the present invention's preparation is narrow, and the variable color acumen; The purity height, impurity is few; Method is simple to operate, is fit to industrial application.
Embodiment
The present invention is further described below in conjunction with specific embodiments, to help understanding content of the present invention, can not limit protection scope of the present invention with following illustrating.
Raw material: benzene methanesulfonic acid acid anhydride, meta-cresol, phosphorus oxychloride, zinc chloride, toluene.
Equipment: three mouthfuls of round-bottomed flasks, ball-type condenser, thermometer, stirring, filtration unit.
Embodiment 1:
A kind of preparation method of m-cresol purple, step is as follows:
(1) condensation reaction: about 0.5～1 hour of 300 milliliters of meta-cresols of exsiccant and 285 gram benzene methanesulfonic acid acid anhydride stirring heating, temperature is controlled at 100～105 ℃, treat to add several times when temperature is cooled to 90～100 ℃ 120 milliliters of phosphorus oxychloride and 120 gram Zinc Chloride Anhydrouss, stirred 6～8 hours under strict this temperature of control.Add 300 milliliters in water in the reaction product that obtains, be heated to 70～80 ℃, slowly add industrial sodium carbonate, heated 5～6 hours, leave standstill, filter, filtrate is neutralized to pH1～2 with 1: 1 hydrochloric acid, leave standstill the thick thing of sub-cloud, heating gets finishing room cresol purple 350 grams to remove meta-cresol.
(2) refining, crude product can be used the butanols recrystallization, uses ethanol in further purification again, applies flexibly the sodium hydrogen carbonate solution dissolving, and separates out crystallization with the dilute hydrochloric acid neutralization.
Embodiment 2:
A kind of preparation method of m-cresol purple, step is as follows:
(1) condensation reaction: get the pure benzene methanesulfonic acid acid anhydride of 285 grams, 300 milliliters of meta-cresols, 120 gram Zinc Chloride Anhydrous and 120 milliliters of phosphorus oxychloride under agitation heat under 95～100 ℃ of conditions.Continue to be warming up to 110～115 ℃, and be incubated 45～50 minutes.After 300 milliliters of hot-water cure, go out excessive meta-cresol with wet distillation, have this moment loose green powder to form, filter, after the drying crude product 350 grams.
(2) refining: crude product can be used the butanols recrystallization, further purifies with ethanol again.Or with sodium hydrogen carbonate solution dissolving, and purify it with dilute hydrochloric acid precipitated.
The discussion of key problem in technology and problem
Emit a large amount of hydrogen chloride gas when (1) benzene methyl yellow acid anhydrides and meta-cresol react, so note ventilating.Strict controlled temperature is wanted in reaction,
If the reactant retrogradation can add small amount of toluene, this moment, temperature can not be above 108 ℃..
(2) the wet distillation purpose is for removing remaining meta-cresol, otherwise is purple crystal.
(3) benzene methanesulfonic acid acid anhydride, phosphorus oxychloride, Zinc Chloride Anhydrous mixed dissolution are the processes of a heat release, so reaction begins and should slowly heat up.
Claims (3)
1. the preparation method of a m-cresol purple is characterized in that: comprise the steps:
(1) condensation reaction: 300 milliliters of meta-cresols of exsiccant and 285 are restrained benzene methanesulfonic acid acid anhydride stirring heating 0.5～1 hour, temperature is controlled at 100～105 ℃, treat to add several times when temperature is cooled to 90～100 ℃ 120 milliliters of phosphorus oxychloride and 120 gram Zinc Chloride Anhydrouss, control and stirred under this temperature 6～8 hours;
(2) refining: as in the reaction product that step (1) obtains, to add 300 milliliters in water, be heated to 70～80 ℃, slowly add industrial sodium carbonate, heated 5～6 hours, and left standstill, filter, filtrate is neutralized to pH 1～2 with 1: 1 hydrochloric acid, leave standstill the thick thing of sub-cloud, add the heat extraction meta-cresol, get finishing room cresol purple.
2. the preparation method of m-cresol purple according to claim 1, it is characterized in that: described step (1) is: get the pure benzene methanesulfonic acid acid anhydride of 285 grams, 300 milliliters of meta-cresols, 120 gram Zinc Chloride Anhydrous and 120 milliliters of phosphorus oxychloride under agitation heat under 95～100 ℃ of conditions, continue to be warming up to 110～115 ℃, and be incubated 45～50 minutes, after 300 milliliters of hot-water cure, go out excessive meta-cresol with wet distillation, filter, get the crude product m-cresol purple after the drying.
3. the preparation method of m-cresol purple according to claim 1, it is characterized in that: described step (2) is: the crude product m-cresol purple butanols recrystallization that step (1) is obtained, purify with ethanol again, or dissolve, and purify with dilute hydrochloric acid precipitated with sodium hydrogen carbonate solution.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011102266805A CN102267976A (en) | 2011-08-09 | 2011-08-09 | Preparation method for m-cresol purple |
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| CN2011102266805A CN102267976A (en) | 2011-08-09 | 2011-08-09 | Preparation method for m-cresol purple |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112608619A (en) * | 2020-12-18 | 2021-04-06 | 袁新华 | Preparation method of tar violet |
| CN112759574A (en) * | 2020-11-27 | 2021-05-07 | 厦门大学 | Purification method of sulfophthalein acid-base indicator |
-
2011
- 2011-08-09 CN CN2011102266805A patent/CN102267976A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112759574A (en) * | 2020-11-27 | 2021-05-07 | 厦门大学 | Purification method of sulfophthalein acid-base indicator |
| CN112608619A (en) * | 2020-12-18 | 2021-04-06 | 袁新华 | Preparation method of tar violet |
| CN112608619B (en) * | 2020-12-18 | 2022-04-29 | 袁新华 | Preparation method of tar violet |
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Application publication date: 20111207 |