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

A technology of nitrotoluene and sulfonic acid liquid, applied in the preparation of sulfonic acid, organic chemistry, etc., can solve the problems of low reduction yield, large catalyst loss and loss, low product purity, etc., and achieves improved catalytic activity, improved conversion rate, The effect of suppressing the 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

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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 increase the life of the catalyst. At the same time, the method is used to reduce the production of CLT acid with high reduction rate, good product purity and less environmental pollution.

Method used

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  • Method for preparing CLT acid (6-chloro-3-nitrotoluene-4-sulfonic acid) by continuous hydrogenation reduction of 6-chloro-3-nitrotoluene-4-sulfonicacid liquid phase
  • Method for preparing CLT acid (6-chloro-3-nitrotoluene-4-sulfonic acid) by continuous hydrogenation reduction of 6-chloro-3-nitrotoluene-4-sulfonicacid liquid phase
  • Method for preparing CLT acid (6-chloro-3-nitrotoluene-4-sulfonic acid) by continuous hydrogenation reduction of 6-chloro-3-nitrotoluene-4-sulfonicacid liquid phase

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Embodiment 1

[0035] This embodiment adopts Pt / Al 2 o 3 Catalyst, the catalyst is based on Raschig ring type Al 2 o 3 As a carrier, the active component Pt is loaded on its surface, and the active component Pt is eggshell-shaped distribution on the surface of the carrier, and the mass of the active component Pt accounts for 0.2% of the mass of the carrier. The following is the use of the Pt / Al 2 o 3 Catalyst, the specific process of obtaining CLT acid by continuous hydrogenation reduction reaction in a fixed bed reactor.

[0036] (1) Add 50 ml of Pt / Al to the fixed bed reactor 2 o 3 catalyst, the Pt / Al 2o 3 Catalyst reduction at 300°C for 2 hours;

[0037] (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 Calcium solution, the input volume is set to 0....

Embodiment 2

[0042] This embodiment adopts Pt / Al 2 o 3 Catalyst, the catalyst is based on Raschig ring type Al 2 o 3 As a carrier, the active component Pt is loaded on its surface, and the active component Pt is eggshell-shaped distribution on the surface of the carrier. The mass of the active component Pt accounts for 0.3% of the mass of the carrier, and the specific surface area of ​​the carrier is 105 meters 2 / g, the pore volume is 0.6 ml / g carrier. The following is the use of the Pt / Al 2 o 3 Catalyst, the specific process of obtaining CLT acid by continuous hydrogenation reduction reaction in a fixed bed reactor.

[0043] (1) Add 50 ml of Pt / Al to the fixed bed reactor 2 o 3 catalyst, the Pt / Al 2 o 3 Catalyst reduction at 300°C for 2 hours;

[0044] (2) The temperature of the system is raised to 120°C, hydrogen gas is continuously fed into the system, and the pressure of the hydrogen gas rises to 4MPa, and a metering pump is used to continuously input saturated 6-chloro-3-ni...

Embodiment 3

[0048] This embodiment adopts Pt / Al 2 o 3 Catalyst, the catalyst is porous cylindrical Al 2 o 3 As a carrier, the active component Pt is loaded on its surface, and the active component Pt is eggshell-shaped distribution on the surface of the carrier. The mass of the active component Pt accounts for 0.4% of the mass of the carrier, and the specific surface area of ​​the carrier is 106 m 2 / g, the pore volume is 0.6 ml / g carrier. The following is the use of the Pt / Al 2 o 3 Catalyst, the specific process of obtaining CLT acid by continuous hydrogenation reduction reaction in a fixed bed reactor.

[0049] (1) Add 100ml Pt / Al to the fixed bed reactor 2 o 3 catalyst, the Pt / Al 2 o 3 Catalyst reduction at 300°C for 2 hours;

[0050] (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 4MPa, and the metering pump is used to continuously input saturated 6-chloro-3-nitrotoluene-4-sulfonic ...

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Abstract

The invention provides a method for preparing CLT acid (6-chloro-3-nitrotoluene-4-sulfonic acid) by continuous hydrogenation reduction of 6-chloro-3-nitrotoluene-4-sulfonicacidliquid phase. The method comprises the steps of passing 6-chloro-3-nitrotoluene-3-sulfonicacid liquid phase and hydrogen through a catalyst for hydrogenation reduction in a manner of continuous feeding and discharging to obtain the CLT acid in a fixed bed reactor by using Pt / Al2O3 as catalyst, wherein the Pt / Al2O3 catalyst uses aluminum oxide with a column structure or a spherical structure as a carrier and platinum (Pt) is loaded on the carrier surface as an active component with a mass ratio of 0.05%-10% of the carrier mass. Compared to prior art, the hydrogenation reduction provided by the invention has a high conversion and a few side reactions, the catalyst has a long useful life and a little pollutions to environment, so that the method has good application prospects and huge economic benefits.

Description

technical field [0001] The invention belongs to the technical field of CLT acid, 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 6-chloro-3-nitrotoluene-4-sulfonic acid is obtained under catalyst conditions -Chloro-3n...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C309/48C07C303/22
Inventor 周生虎王向东
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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