Method for synthesizing dyestuff intermediate H acid by naphthalene

A technology for synthesizing dyes and intermediates, applied in 1 field, can solve problems such as difficult treatment of high-salt COD wastewater, and achieve the effects of reducing secondary pollution, reducing emissions, and reducing reaction time

Active Publication Date: 2010-06-02

泰兴锦汇化工有限公司

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Problems solved by technology

This method is currently the main method for producing H acid in China. The method of alkali fusion is to make the sulfonic acid group on the T acid alkali-dissolved under alkaline co...

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Abstract

The invention discloses a method for synthesizing dyestuff intermediate H acid by using naphthalene. In the method, the H acid is prepared by carrying out the steps of sulfonating with sulfonating agent sulfuric acid, nitrating with concentrated nitric acid, separating and neutralizing, reducing by catalytic hydrogenation, acid hydrolysis, and segregating on refined naphthalene. The H acid prepared by the method is suitable for various dyestuffs of active azo and the like, and can also be used for synthesizing medicaments. The synthesis method has the advantages of no tri-sulfonation, little waste acid amount, no alkali solution, less generated sulfur dioxide gas and inorganic salt, high yield, and reduced COD and secondary pollution of waste slag because of no iron cement generated by hydrogenation reduction.

Application Domain

Sulfonic acids salts preparation

Technology Topic

SlagSulfur dioxide +9

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Examples

Experimental program(1)

Example Embodiment

[0028] Example 1

[0029] Add 192 g of refined naphthalene and 792 g of 98% sulfuric acid into a three-necked flask, raise the temperature to 160° C., stir at this temperature for 1 hour, then raise the temperature to 175° C., and stir for 6 hours to carry out the reaction. After the reaction, cool to 40°C and add 135g of water to dilute the concentration of sulfuric acid to extract refined naphthalene 2,6-disulfonic acid, heat up to 65°C and filter to obtain 142g of naphthalene 2,6-disulfonic acid, then add 130g of water to the filtrate , dilute the sulfuric acid concentration to 40%, extract naphthalene-2,7-disulfonic acid, cool to 30°C and filter to obtain 180g naphthalene-2,7-disulfonic acid.

[0030] In addition, dissolve the previously fractionated naphthalene-2,6-disulfonic acid into 50 g of 80% sulfuric acid, add 15 g of water, adjust the sulfuric acid concentration to 72%, raise the temperature to 195° C., and stir at this temperature for 10 hours for isomerization. Add the filtrate filtered by the above-mentioned naphthalene-2,7-disulfonic acid into the isomerization solution, raise the temperature to 150°C and reduce the pressure to 100 mm Hg for 2 hours, control the concentration of sulfuric acid to 78% and cool, add 60 g of refined naphthalene and 98 % Sulfuric acid 10g was heated up to 160°C, dehydration under reduced pressure for 1 hour, followed by sulfonation at 175°C for 6 hours, separated by the above method, and repeated to obtain refined naphthalene-2,7-disulfonic acid.

[0031] Weigh 1000g of 98% sulfuric acid and add 500g of naphthalene-2,7-disulfonic acid prepared above, adjust the sulfuric acid dehydration value of the solution, cool, add 150g of 99% nitric acid in 3 hours in the range of 0-10°C, and then control The temperature was 9°C, and the reaction was carried out for 3 hours. Add 1000g of water to the reactant, dilute the concentration of sulfuric acid to 52%, stir for 2 hours in the range of 95-100°C, remove excess nitric acid in vacuum, and analyze with liquid chromatography after cooling, the target substance 1,8- Dinitronaphthalene-3,6-disulfonic acid HLPC is 92%, and 1100 g is obtained after filtration, and the conversion rate is 92.3%.

[0032] Take 1000 g of the above-mentioned 1,8-dinitronaphthalene-3,6-disulfonic acid filter cake and add 100 g of water to make a slurry. Use 600g of 32% liquid caustic soda to dissolve pH=7.5, add it to a 2L hydrogenation reactor, add 15g of catalyst (nickel-molybdenum-aluminum catalyst, molybdenum content 2%), raise the temperature to 100°C, and pass the pressure to 1.8MPa after deoxygenation and nitrogen flushing. 100-120°C, react for 3 hours, the end point will be reached if the pressure does not drop, HLPC≥96%, separate and filter to obtain 1,8-diaminonaphthalene-3,6-disulfonic acid sodium salt solution.

[0033] Take 500g of the above-mentioned 1,8-diaminonaphthalene-3,6-disulfonic acid sodium salt solution, add 300g of 98% sulfuric acid under stirring, heat up to 120°C after 30 minutes, keep the temperature for 10 hours, then slowly cool down to 40°C, The monosodium salt of H acid was separated and extracted, washed with 20 ml of water, dried, and the detection purity was HLPC≥95%, and the conversion rate was 91%.

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Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

The reaction steps are simple
Short reaction time

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Low cost High yield Reduce emissions Reduce COD Reduce secondary pollution Sulfuric acid Inorganic salts Catalytic hydrogenation Photochemistry Nitric acid Naphthalene

Method for synthesizing dyestuff intermediate H acid by naphthalene

A technology for synthesizing dyes and intermediates, applied in 1 field, can solve problems such as difficult treatment of high-salt COD wastewater, and achieve the effects of reducing secondary pollution, reducing emissions, and reducing reaction time

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Examples

Example Embodiment

PUM

Description & Claims & Application Information

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