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Process for preparing lemon chrome

A technology of tartrazine and p-aminobenzenesulfonic acid, applied in chemical instruments and methods, azo dyes, organic dyes, etc., can solve the problems of lack of reaction conversion rate, high product purity, and low content of organic impurities

Inactive Publication Date: 2008-10-29
上海染料研究所有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] In summary, this area lacks a method for preparing tartrazine with high reaction conversion rate, high product purity and low organic impurity content

Method used

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  • Process for preparing lemon chrome
  • Process for preparing lemon chrome
  • Process for preparing lemon chrome

Examples

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preparation example Construction

[0040] figure 1 It is the process flow chart of the preparation method of tartrazine of the present invention, and DMAS is dimethyl 2-acetyl succinate, sodium nitrite is sodium nitrite, and p-acid is p-aminobenzenesulfonic acid.

[0041] like figure 1 Shown, realize the preparation method of tartrazine of the present invention and comprise diazotization reaction, condensation reaction, coupling reaction, hydrolysis reaction, and aftertreatment step, wherein each aftertreatment step comprises crystallization step, membrane separation step and drying step.

[0042] phase transfer catalyst

[0043] The phase transfer catalyst is selected from auxiliary agents such as ethanol, Span-Tween series, polyethylene glycol series, Pingpinga 0 (such as Pingpinga 0 produced by Shanghai Auxiliary Factory) or emulsifiers, dispersants, preferably polyethylene glycol Alcohol phase transfer catalyst, more preferably polyethylene glycol 400. The dosage is 0.1-2.0% of the weight of the whole re...

Embodiment 1

[0063] In a 500mL four-neck bottle, add 180mL of 60°C hot water, add 20g of polyethylene glycol 400 (PEG-400), add 34.6g (0.20mol) of p-aminobenzenesulfonic acid under rapid stirring, stir for ten minutes, cool to room temperature, Add industrial hydrochloric acid 32mL (31%). Continue to cool to 0-5°C, add 47g (0.20mol) of 30% sodium nitrite solution dropwise, maintain the temperature at 5-10°C, and finish adding for about 20 minutes. Congo red test paper is blue and potassium iodide starch test paper is light blue. Continue to stir for 20 minutes after the addition, add a small amount of sulfamic acid to eliminate excess nitrous acid.

[0064] In the above diazo liquid, after stirring for 5 minutes, add 37.64 g (0.20 mol) of DMAS (dimethyl 2-acetylsuccinate) in a trickle, control the temperature at 10-15 ° C, and slowly add 15 wt % disodium hydrogen phosphate solution dropwise Adjust the pH to 5.0, and the system turns into a transparent wine red. After the diazonium salt d...

Embodiment 2

[0069] Replace 20 g of polyethylene glycol 400 (PEG-400) with 15 g of polyethylene glycol 1000 (PEG-1000), and the rest are the same as in Example 1. 105.6 g of finished product was obtained, the content was 90.5%, the liquid phase purity was 99.25% (238nm), and the yield was 91.1%.

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Abstract

The invention discloses a preparing method of lemon yellow through condensing, coupling and hydrolyzing, which improves switching rate and production purity with lower organic impurity content.

Description

technical field [0001] The invention relates to a preparation method of food coloring, in particular to a preparation method of tartrazine. Background technique [0002] Food additive food coloring can be divided into two categories: synthetic coloring and natural coloring. Compared with natural pigments, synthetic pigments have the advantages of bright color, multiple hues, stable performance, strong tinting strength, high fastness, easy color matching, convenient use, low cost, and wide application. Coupled with the practice of various countries for hundreds of years, from more than one hundred kinds at most to more than thirty kinds. Food additive food coloring is widely used in food, medicine, cosmetics, paper, daily necessities, toys, new packaging materials and other fields. It can be said that the safety of synthetic pigments allowed to be used in various countries is quite reliable. In food coloring, synthetic pigments Far more than natural coloring is used. With ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09B29/036
Inventor 丁秋龙王丽斌
Owner 上海染料研究所有限公司