Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method for preparing DSD (4,4'-Diamino 2,2'-Stilbene Disulphonic) acid by hydrogenating and reducing disodium dinitrosalicylate (DNS) at high temperature

A technology of diaminostilbene and dinitrostilbene, which is applied in the field of preparing DSD acid, can solve the problems of unseen industrialization of DSD acid hydrogenation process, low concentration of DNS acid disodium salt, unqualified cotton thread dyeing index, etc. , to achieve the effect of controlling the generation of colored impurities, increasing the reaction rate and reducing the one-time investment

Active Publication Date: 2014-01-08
HEBEI CAIKE CHEM CO LTD +1
View PDF4 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this process has the following disadvantages: the first is low yield; the second is that the reaction temperature is low, the reaction rate is slow, and it is easy to generate azo compounds, the resulting product is low in purity, resulting in unqualified cotton thread dyeing indicators; the third is that the DNS acid used The concentration of disodium salt is low, which limits the production capacity of the equipment. To increase the production capacity, it is necessary to increase the investment in equipment.
Therefore, there has been no report on the industrialization of the DSD acid hydrogenation process

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In a 1000L stirred tank, add 400L of water and 400kg of solid DNS acid disodium salt, start stirring, and raise the temperature to 120°C to fully dissolve the DNS acid disodium salt.

[0025] Add 12kg of platinum-carbon catalyst with a metal mass fraction of 3% in a 1000L hydrogenation reactor, add 150L of water, replace it with a nitrogen atmosphere, and feed hydrogen to maintain a pressure of 1.8MPa. Start the reactor to stir, raise the temperature to 250°C, and use the feed pump to continuously inject the DNS acid disodium salt solution in the dissolution tank into the hydrogenation reactor at a constant speed for 1 hour to react. After the feed was completed, the above reaction conditions were maintained for 20 min.

[0026] The hydrogen in the reactor is emptied and replaced with a nitrogen atmosphere, the catalyst is filtered out through a high-performance filter, and the catalyst is recovered and retained for further use, and the material enters the acid analysis...

Embodiment 2

[0030] In a 1000L stirred tank, add 150L of water and 350kg of solid DNS acid disodium salt, start stirring, and raise the temperature to 120°C to fully dissolve the DNS acid disodium salt.

[0031] Add 3.5kg of palladium-carbon catalyst with a metal mass fraction of 1% into a 1000L hydrogenation reactor, add 150L of water, replace it with a nitrogen atmosphere, and feed hydrogen to maintain a pressure of 0.8MPa. Start the reactor to stir, raise the temperature to 300°C, and use the feed pump to continuously inject the DNS acid disodium salt solution in the dissolution tank into the hydrogenation reactor at a constant speed for 1.5 hours to react. After the feed was completed, the above reaction conditions were maintained for 20 min.

[0032] The hydrogen in the reactor is emptied and replaced with a nitrogen atmosphere, the catalyst is filtered out through a high-performance filter, and the catalyst is recovered and retained for further use, and the material enters the acid a...

Embodiment 3

[0036] In a 1000L stirred tank, add 200L of water and 300kg of solid DNS acid disodium salt, start stirring, and raise the temperature to 120°C to fully dissolve the DNS acid disodium salt.

[0037] Add 1.5kg of palladium carbon catalyst with a metal mass fraction of 10% in a 1000L hydrogenation reactor, add 150L of water, replace it with a nitrogen atmosphere, and feed hydrogen to maintain a pressure of 3MPa. Start the reactor to stir, raise the temperature to 260°C, and use the feed pump to continuously inject the DNS acid disodium salt solution in the dissolution tank into the hydrogenation reactor at a constant speed for 2 hours to react. After the feed was completed, the above reaction conditions were maintained for 20 min.

[0038] The hydrogen in the reactor is emptied and replaced with a nitrogen atmosphere, the catalyst is filtered out through a high-performance filter, and the catalyst is recovered and retained for further use, and the material enters the acid analys...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention relates to a method for preparing DSD (4,4'-Diamino 2,2'-Stilbene Disulphonic) acid, in particular to a method for preparing the DSD acid by hydrogenating and reducing disodium dinitrosalicylate (DNS) at high temperature. The method comprises the following steps of: (1) dissolving a raw material DNS (DiNitroSalicylic) acid; (2) adding a catalyst and materials into a hydrogenating reactor for carrying out hydrogenation; (3) filtering the catalyst; (4) precipitating with acid; and (5) carrying out filter pressing by virtue of a plate frame. The invention is innovative in that the method for preparing the DSD acid by hydrogenating and reducing the disodium dinitrosalicylate is developed. High-concentration disodium dinitrosalicylate is adopted to prepare the DSD acid, thus space-time capacity of equipment is improved, and one-time investment of the equipment is reduced; and a high temperature continuous feeding way is adopted for reaction, thus the reaction is carried out toward the direction more beneficial to a main reaction, a side reaction is effectively controlled, generation of coloured impurity can be effectively controlled, and quality and yield of the DSD acid are greatly improved.

Description

technical field [0001] The invention relates to a method for preparing DSD acid, in particular to a method for preparing DSD acid by hydrogenating and reducing DNS acid disodium salt at high temperature. Background technique [0002] 4,4'-diaminostilbene 2,2'-disulfonic acid (DSD acid) and its disodium salt are important intermediates for the preparation of stilbene-type optical brighteners, Qi's direct dyes and reactive dyes. Direct dyes and a variety of reactive dyes produced by DSD acid are widely valued due to their non-toxicity and non-accumulation in the human body. [0003] At present, the production process of DSD acid mainly adopts the method of preparing DSD acid by reducing DNS sodium salt with iron powder. Patent document CN1785970A discloses a method for preparing DSD acid by reducing DNS sodium salt with iron powder. The process includes: adding sodium acetate, formic acid or sodium formate and concentrated sulfuric acid to a reactor containing iron powder and...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07C309/46C07C303/22
CPCY02P20/584
Inventor 张维金石强
Owner HEBEI CAIKE CHEM CO LTD
Features
  • Generate Ideas
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com