Method for synthesizing o-chloro-p-aminotoluene from o-chloro-p-nitrotoluene through catalytic hydrogenation

A technology for p-nitrotoluene and p-aminotoluene is applied in the field of o-chloro-p-nitrotoluene catalytic hydrogenation to synthesize o-chloro-p-aminotoluene, and can solve the problems of environmental pollution, complex production process by alkali sulfide reduction method, increased production cost and the like , to achieve the effect of reducing production costs, simple and controllable process operation

Inactive Publication Date: 2018-12-21
宜宾市南溪区红源化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The production process of the alkali sulfide reduction method is complicated, and the product quality is affected by many factors
Alkali sulfide is a strong alkali, and the corrosion of equipment is more complicated and serious. In addition,

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Step 1: Input quality is 1 ton of ortho-chloro-p-nitrotoluene, then dissolve the ortho-chloro-p-nitrotoluene in the reaction kettle according to the mass ratio of 1:1. It is 1:0.005 with Raney nickel catalyst mass ratio, add the Raney nickel catalyst that quality is 5 kilograms;

[0019] Step 2: After the o-chloro-p-nitrotoluene is dissolved in the reactor, hydrogen gas is passed into the solution, the molar ratio of o-chloro-p-nitrotoluene to hydrogen is 1:3.5, the reaction temperature is controlled to be 90°C, and the reaction pressure is controlled to be 1.6MPa, the reduction reaction time is 5 hours;

[0020] Step 3: transfer the reducing solution obtained in step 2 into a solvent distillation tower, control the temperature at 70° C., carry out atmospheric distillation to separate the solute, and obtain crude o-chloro-p-aminotoluene;

[0021] Step 4: Transfer the crude o-chloro-p-aminotoluene obtained in step 3 to a rectification tower, control the temperature at 1...

Embodiment 2

[0023] Step 1: Input quality is 1 ton of ortho-chloro-p-nitrotoluene, then dissolve the ortho-chloro-p-nitrotoluene in the reaction kettle according to the mass ratio of 1:1. It is 1:0.005 with Raney nickel catalyst mass ratio, add the Raney nickel catalyst that quality is 5 kilograms;

[0024] Step 2: After the o-chloro-p-nitrotoluene is dissolved in the reactor, hydrogen gas is introduced into the solution, the molar ratio of o-chloro-p-nitrotoluene to hydrogen is 1:3.7, the reaction temperature is controlled to be 93°C, and the reaction pressure is controlled to be 1.9MPa, the reduction reaction time is 5.5 hours;

[0025] Step 3: transfer the reducing solution obtained in step 2 into a solvent distillation tower, control the temperature at 75° C., carry out atmospheric distillation to separate the solute, and obtain crude o-chloro-p-aminotoluene;

[0026] Step 4: Transfer the crude o-chloro-p-aminotoluene obtained in step 3 to a rectification tower, control the temperatur...

Embodiment 3

[0028] Step 1: Input quality is 1 ton of ortho-chloro-p-nitrotoluene, then dissolve the ortho-chloro-p-nitrotoluene in the reaction kettle according to the mass ratio of 1:1. It is 1:0.005 with Raney nickel catalyst mass ratio, add the Raney nickel catalyst that quality is 5 kilograms;

[0029] Step 2: After the o-chloro-p-nitrotoluene is dissolved in the reactor, hydrogen gas is introduced into the solution, the molar ratio of o-chloro-p-nitrotoluene to hydrogen is 1:4, the reaction temperature is controlled at 95°C, and the reaction pressure is controlled at 2.2MPa, the reduction reaction time is 6 hours;

[0030] Step 3: transfer the reducing solution obtained in step 2 into a solvent distillation tower, control the temperature at 80° C., carry out atmospheric distillation to separate the solute, and obtain crude o-chloro-p-aminotoluene;

[0031] Step 4: Transfer the crude o-chloro-p-aminotoluene obtained in step 3 into a rectification tower, control the temperature at 120...

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Abstract

The invention discloses a method for synthesizing o-chloro-p-aminotoluene from o-chloro-p-nitrotoluene through catalytic hydrogenation. The method comprises the following steps: enabling the o-chloro-p-nitrotoluene to be dissolved in a methyl alcohol solvent according to a mass ratio of 1 to 1, and adding a raney nickel catalyst; after dissolving, feeding hydrogen, wherein a molar weight proportion of the o-chloro-p-nitrotoluene to the hydrogen is 1 to (3.5 to 4), controlling a reaction temperature to be 90-95 DEG C, and controlling a reaction pressure to be 1.6-2.2 MPa; while an input amountof the o-chloro-p-nitrotoluene is 1 ton, reducing reaction time is about 5-6 hours; transferring reducing solution to a solvent distillation column, performing atmospheric distillation to obtain coarse o-chloro-p-aminotoluene; transferring the coarse o-chloro-p-aminotoluene to a rectifying tower, performing negative pressure distillation to obtain refined o-chloro-p-aminotoluene, wherein a purityof the o-chloro-p-aminotoluene measured by using a gas chromatographic method is greater than 98.00%. Multi-sulfur waste water and multi-sulfur waste residues are not generated in a production process, the method is energy-saving and environmentally friendly, an operating process of the technology is simple and controllable, and production cost is reduced.

Description

technical field [0001] The invention relates to the industrial catalysis field of petrochemical industry, in particular to a method for synthesizing o-chloro-p-aminotoluene by catalytic hydrogenation of o-chloro-p-nitrotoluene. technical background [0002] O-chloro-p-aminotoluene is referred to as 2B oil for short. 2B oil is mainly used as an intermediate in the organic synthesis industry, and can also be used to produce pigments, coatings and pesticides. [0003] At present, most domestic 2B oil production methods adopt the alkali sulfide reduction method. Specifically, sulfur and sodium sulfide are formulated into sodium polysulfide, and sodium polysulfide is used to reduce o-chloro-p-nitrotoluene to 2B oil crude product, 2B oil crude product After rinsing and vacuum distillation, it is refined into 2B oil products. The production process produces a large amount of alkaline wastewater and alkali sulfide residues. The reaction chemical formula of the reduction method is: ...

Claims

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Application Information

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IPC IPC(8): C07C209/36C07C211/52
CPCC07C209/365C07C211/52
Inventor 李文生杨建平唐邦正
Owner 宜宾市南溪区红源化工有限公司
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