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

Method for preparing dichloroacetic acid by selective dechlorination of trichloroacetic acid

A technology of trichloroacetic acid and dichloroacetic acid, applied in the preparation of carboxylate, chemical instruments and methods, preparation of organic compounds, etc., can solve the problems of low product purity, long process flow, large amount of waste water, etc., and achieve hydrogen The effect of uniform concentration, favorable selectivity and low equipment cost

Active Publication Date: 2018-10-16
XIAN CATALYST NEW MATERIALS CO LTD
View PDF5 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Dichloroacetic acid and trichloroacetic acid can be separated by crystallization according to the difference in melting point, but the product purity is not high
[0003] Chinese patent CN1129210A discloses a method for producing dichloroacetic acid. The mother liquor of chloroacetic acid is subjected to secondary distillation, water, acetic acid and monochloroacetic acid are separated, thiourea is added, and after chemical reaction, filtration, acidification, extraction, distillation and other operations, The obtained dichloroacetic acid has a purity of more than 95%, but the whole technological process is long, the cost is high, and the amount of waste water is large

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

[0022] 1. Catalyst loading

[0023] Fill the catalyst diluted with coal-based activated carbon in the fixed-bed catalytic reactor, according to the catalyst dilution ratio, the mass fraction of the catalyst in each section of A, B, and C is successively 30%, 60% and 100%, wherein the catalyst contains Pt The loading of Pd is 0.5%, the loading of Pd is 0.3%, the loading of Ag is 0.2%, the loading of Mg is 0.1%, the loading of Al is 0.4%, and the rest is coal-based activated carbon. The reaction tube internals and connecting pipes of the fixed bed catalytic reactor are made of carbon steel lining enamel.

[0024] 2. Pretreatment

[0025] The air in the reactor is replaced by nitrogen gas from the air inlet on the top and side of the fixed-bed catalytic reactor for 2 hours, then the nitrogen is switched to pure hydrogen, and the temperature in the fixed-bed catalytic reactor is raised to 200°C at a rate of 1°C / min. Hold for 3 hours to activate and pretreat the catalyst, then co...

Embodiment 2

[0029] 1. Catalyst loading

[0030] Fill the catalyst diluted with coal-based activated carbon in the fixed-bed catalytic reactor, according to the catalyst dilution ratio, the mass fraction of the catalyst in each section of A, B, and C is successively 40%, 60% and 90%, wherein the Pt in the catalyst The loading of Pd is 0.9%, the loading of Pd is 0.1%, the loading of Ag is 0.1%, the loading of Mg is 0.2%, the loading of Al is 0.1%, and the rest is coal-based activated carbon. The reaction tube internals and connecting pipes of the fixed bed catalytic reactor are made of carbon steel lining enamel.

[0031] 2. Pretreatment

[0032] The air in the reactor is replaced by nitrogen gas from the air inlet on the top and side of the fixed-bed catalytic reactor for 2 hours, then the nitrogen is switched to pure hydrogen, and the temperature in the fixed-bed catalytic reactor is raised to 200°C at a rate of 1°C / min. Hold for 3 hours to activate and pretreat the catalyst, then lower...

Embodiment 3

[0036] 1. Catalyst loading

[0037] Fill the catalyst diluted with coal-based activated carbon in the fixed-bed catalytic reactor, according to the catalyst dilution ratio, the mass fraction of the catalyst in each section of A, B, and C is successively 30%, 70% and 100%, wherein the catalyst contains Pt The loading of Pd is 0.3%, the loading of Pd is 0.4%, the loading of Ag is 0.2%, the loading of Mg is 0.1%, the loading of Al is 0.3%, and the rest is coal-based activated carbon. The reaction tube internals and connecting pipes of the fixed bed catalytic reactor are made of carbon steel lining enamel.

[0038] 2. Pretreatment

[0039] The air in the reactor is replaced by nitrogen gas from the air inlet on the top and side of the fixed-bed catalytic reactor for 2 hours, then the nitrogen is switched to pure hydrogen, and the temperature in the fixed-bed catalytic reactor is raised to 200°C at a rate of 1°C / min. Hold for 3 hours to activate and pretreat the catalyst, then lowe...

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

PropertyMeasurementUnit
diameteraaaaaaaaaa
Login to View More

Abstract

The invention discloses a method for preparing dichloroacetic acid by selective dechlorination of trichloroacetic acid. According to the method, a fixed bed catalytic reactor is adopted to convert thetrichloroacetic acid into the dichloroacetic acid with the conversion rate being greater than 99.5% and the selectivity being greater than 98%, and the balance comprises monochloroacetic acid and acetic acid. A catalyst is a precious metal catalyst supported by coal-based activated carbon; a trichloroacetic acid solution and hydrogen are preheated to reach the reaction temperature, enter from thetop of the reactor, and contact with the catalyst from top to bottom, and a hydrodechlorination reaction occurs; a gas replenishing port is disposed on the outer wall of the reactor; the hydrogen iscontinuously replenished during the reaction, so that the hydrogen concentration in the reactor is maintained at 10% to 40%; liquid phase and gas phase products produced are discharged from the bottomof the reactor; and the liquid phase products are distilled to obtain high-purity dichloroacetic acid products after condensation and gas-liquid separation.

Description

technical field [0001] The invention belongs to the technical field of selective catalytic hydrogenation process, in particular to a method for preparing dichloroacetic acid by selective catalytic hydrogenation dechlorination. Background technique [0002] Dichloroacetic acid is an important chemical intermediate, which has many applications in the fields of medicine, pesticides and active fuels. It can be used to prepare dichloroacetic acid salt, glyoxylic acid and dichloroacetyl chloride, etc., or to prepare cellulose Derivatives of plasticizers. The preparation methods of dichloroacetic acid include: chloroacetic acid mother liquor distillation method, iodine-catalyzed acetic acid rechlorination method and chloral method. Wherein the purity of dichloroacetic acid prepared by the first two methods is relatively low, no more than 90%, and high-purity dichloroacetic acid can be obtained by cyaniding, dechlorinating and rehydrolyzing chloral, but the process is complicated a...

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 Applications(China)
IPC IPC(8): C07C51/377C07C53/16
CPCC07C51/377C07C53/16
Inventor 林涛万克柔程杰张炳亮张力陈丹张之翔曾永康曾利辉高武
Owner XIAN CATALYST NEW MATERIALS CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

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

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com