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Method for preparing CLT acid by using liquid-phase 6-chloro-3-nitrotoluene-4-sulfonic acid (CLT) in continuous hydrogenation reduction process

A technology of nitrotoluene and sulfonic acid solution, which is applied in the preparation of sulfonic acid, chemical instruments and methods, organic chemistry, etc., can solve the problems of large catalyst loss, low reduction yield, and low product purity, and reduce input costs , Improve catalytic activity and inhibit dechlorination reaction

Active Publication Date: 2015-04-29
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Technical purpose of the present invention is aimed at at present in the process of producing CLT acid with toluene sulfonation route, when adopting iron powder etc. as catalyst reduction 6-chloro-3 nitrotoluene-4-sulfonic acid, the reduction yield produced is low, Aiming at problems such as low product purity, large loss of catalyst loss, and serious environmental pollution, a method for preparing CLT acid by liquid-phase continuous hydrogenation reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid is provided, which can effectively avoid The active components of the catalyst are lost due to filtration, and the catalyst can be reused to improve the life of the catalyst. At the same time, when the method is used to reduce the production of CLT acid, the yield of CLT acid is high, the product purity is good, and the environmental pollution is less

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] This embodiment adopts Pd / Al 2 o 3 Catalyst, the catalyst is based on Raschig ring type Al 2 o 3 As a carrier, the active component Pd is loaded on its surface, and the active component Pd is eggshell-shaped distribution on the surface of the carrier, and the mass of the active component Pd accounts for 0.3% of the mass of the carrier. The following is the use of the Pd / Al 2 o 3 Catalyst, the specific process of obtaining CLT acid by continuous hydrogenation reduction reaction in a fixed bed reactor.

[0035] (1) Add 100ml Pd / Al to the fixed bed reactor 2 o 3 Catalyst, the Pd / Al with hydrogen 2 o3 Catalyst reduction at 300°C for 2 hours;

[0036] (2) The temperature of the system is raised to 80°C, hydrogen is continuously fed into the system, the pressure of the hydrogen is raised to 4MPa, and the saturated 6-chloro-3-nitrotoluene-4-sulfonic acid with a concentration of 5% by weight is continuously input by a metering pump Sodium salt solution, the input volum...

Embodiment 2

[0039] This embodiment adopts Pd / Al 2 o 3 Catalyst, the catalyst is based on Raschig ring type Al 2 o 3 As a carrier, the active component Pd is loaded on its surface, and the active component Pd is distributed in an eggshell shape on the surface of the carrier. The mass of the active component Pd accounts for 0.3% of the mass of the carrier, and the specific surface area of ​​the carrier is 175 meters 2 / g, the pore volume is 0.6 ml / g carrier. The following is the use of the Pd / Al 2 o 3 Catalyst, the specific process of obtaining CLT acid by continuous hydrogenation reduction reaction in a fixed bed reactor.

[0040] (1) Add 200ml Pd / Al to the fixed bed reactor 2 o 3 Catalyst, the Pd / Al with hydrogen 2 o 3 Catalyst reduction at 300°C for 2 hours;

[0041] (2) The temperature of the system is raised to 120°C, hydrogen is continuously fed into the system, the pressure of hydrogen is raised to 4MPa, and saturated 6-chloro-3-nitrotoluene-4-sulfonate with a concentration...

Embodiment 3

[0044] This embodiment adopts Pd / Al 2 o 3 Catalyst, the catalyst is porous cylindrical Al 2 o 3 As a carrier, the active component Pd is loaded on its surface, and the active component Pd is eggshell-shaped distribution on the surface of the carrier. The mass of the active component Pd accounts for 0.5% of the mass of the carrier, and the specific surface area of ​​the carrier is 187 meters 2 / g, the pore volume is 0.65 ml / g carrier. The following is the use of the Pd / Al 2 o 3 Catalyst, the specific process of obtaining CLT acid by continuous hydrogenation reduction reaction in a fixed bed reactor.

[0045] (1) Add 200ml Pb / Al to the fixed bed reactor 2 o 3 Catalyst, the Pd / Al with hydrogen 2 o 3 Catalyst reduction at 300°C for 2 hours;

[0046] (2) The temperature of the system is raised to 100°C, hydrogen is continuously fed into the system, the pressure of the hydrogen is raised to 5MPa, and the metering pump is used to continuously input saturated 6-chloro-3-nitr...

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Abstract

The invention provides a method for preparing CLT acid by using liquid-phase 6-chloro-3-nitrotoluene-4-sulfonic acid (CLT) in a continuous hydrogenation reduction process. The method comprises the following steps of: using Pd / Al2O3 as a catalyst in a fixed bed reactor; performing hydrogenation reduction on the liquid-phase 6-chloro-3-nitrotoluene-4-sulfonic acid in the manner of continuously feeding and discharging through the catalyst to obtain the CLT acid, wherein the Pd / Al2O3 catalyst uses a columnar structure alumina or spherical alumina as a carrier, the surface of the catalyst is loaded with an active component metal palladium (Pd), and the load mass of the active component Pd is 0.05-10% of the mass of the carrier. Compared with the prior art, the method provided by the invnetion has the advantages of high conversion rate of the hydrogenation reduction reaction, few side reaction, long service life of the catalyst, low environmental pollution, good application prospect and great economical benefit.

Description

technical field [0001] The invention belongs to the technical field of synthesizing CLT acid by a catalytic hydrogenation reduction process, and in particular relates to a method for preparing CLT acid by liquid-phase continuous hydrogenation reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid. Background technique [0002] 6-chloro-3-aminotoluene-4-sulfonic acid, its English name is 6-chloro-3-nitrotoluene-4-sulfonic acid, referred to as CLT acid. CLT acid is an important red organic pigment intermediate. It is mainly used in the production of C.I. Pigment Red 52 and C.I. Pigment Red 53 in the pigment industry. The pigment is widely used in paints, coatings, color inks, rubber and plastic coloring, etc. Its main production processes include: [0003] (1) Toluene sulfonation route: use toluene as raw material, sulfonate, chlorinate, nitrate, and neutralize in concentrated sulfuric acid to obtain 6-chloro-3nitrotoluene-4-sulfonic acid, and then convert 6 -Chloro-3nitrotolu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C309/48C07C303/22B01J23/44B01J35/02B01J35/08
Inventor 周生虎林超
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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