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Hydrodechlorination method for producing high-purity monochloro acetic acid

A technology for catalytic hydrogenation and chloroacetic acid, applied in chemical instruments and methods, preparation of organic compounds, catalysts for physical/chemical processes, etc., can solve problems such as low selectivity, limited processing capacity, unrealizable separation and removal, etc., to achieve High reaction efficiency, high activity and selectivity, and the effect of suppressing by-product acetic acid and other polymers

Inactive Publication Date: 2016-04-20
XIAN CATALYST NEW MATERIALS CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Dichloroacetic acid is harmful to the human body, making monochloroacetic acid obtained by chlorination unable to be used in food additives, drugs and cosmetics, which not only pollutes the environment, but also reduces the competitiveness of products
[0003] Since the boiling points of monochloroacetic acid and dichloroacetic acid are very close, it is impossible to separate and remove dichloroacetic acid in monochloroacetic acid by distillation in industry
Chinese patent CN101528657A discloses a method, including treating a mixture of monochloroacetic acid and dichloroacetic acid (2% to 20%) at a temperature of 130 to 170°C and a pressure of 0.1 to 1 MPa, and making dichloroacetic acid (2% to 20%) by catalytic hydrogenation. Chloroacetic acid undergoes dechlorination reaction, but the application system of this method is simple, only the composition of monochloroacetic acid and dichloroacetic acid is described, and the chlorination products in industrial production often contain impurities such as acetic acid, water and hydrochloric acid
Chinese patent CN1309115A discloses a method comprising hydrogenation of monochloroacetic acid containing 10 ppm to 2% by weight of dichloroacetic acid and 0 to 5% by weight of acetic acid, using activated carbon and silica carriers loaded with 0.1 to 3% palladium, but this The method is suitable for dichloroacetic acid with a content of less than 2wt%. When the content of dichloroacetic acid exceeds 2wt%, the content of dichloroacetic acid cannot be effectively reduced while suppressing the formation of acetic acid. At the same time, the method also includes the use of palladium as a catalyst. Under an atmospheric pressure and a reaction temperature of 100-180°C, the selective hydrodechlorination reaction of dichloroacetic acid occurs, and the reaction product enters the hydrogenation tower for repeated hydrogenation, thereby obtaining monochloroacetic acid with a lower content of dichloroacetic acid, but the hydrogenation process is repeated To carry out, making it more time-consuming, and uneconomical, low production efficiency
In the above-mentioned patents, compared with the traditional process, the purification effect of monochloroacetic acid has been improved, but there are still problems such as limited processing capacity, low processing efficiency, low selectivity, complicated process and non-compliance with chlorination solution. actual production issues

Method used

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  • Hydrodechlorination method for producing high-purity monochloro acetic acid
  • Hydrodechlorination method for producing high-purity monochloro acetic acid
  • Hydrodechlorination method for producing high-purity monochloro acetic acid

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Embodiment 1

[0030] This embodiment includes the following steps:

[0031] Step 1. The fixed-bed reactor is filled with a catalyst bed in a staged packing method. The catalyst bed is composed of a palladium-carbon catalyst layer 1 and an inert material layer 2 that are overlapped (such as figure 1 (Shown), the height of each palladium-carbon catalyst layer 1 in the catalyst bed is 1.0 times the inner diameter of the fixed bed reactor, and the height of each inert material layer 2 in the catalyst bed is 0.5 times the inner diameter of the fixed bed reactor, the uppermost layer and the lowermost layer of the catalyst bed are both inert material layer 2, the number of layers of the palladium-carbon catalyst layer 1 is not less than 3; the palladium-carbon catalyst layer 1 Consists of the following components by mass percentage: 1.0% active component, 0.1% metal promoter, the balance being a carrier, the active component is Pd, the metal promoter is Mg, and the carrier is activated carbon; The a...

Embodiment 2

[0036] The method for producing high-purity monochloroacetic acid by catalytic hydrodechlorination in this embodiment is the same as that of embodiment 1, except that the metal promoter in step 1 is Ba, Ce, La, Fe or Al, or Ba A mixture of at least two of, Ce, La, Fe, Mg and Al.

Embodiment 3

[0038] This embodiment includes the following steps:

[0039] Step 1. The fixed-bed reactor is filled with a catalyst bed in a staged packing method. The catalyst bed is composed of a palladium-carbon catalyst layer 1 and an inert material layer 2 that are overlapped (such as figure 1 (Shown), the height of each palladium-carbon catalyst layer 1 in the catalyst bed is 1.0 times the inner diameter of the fixed bed reactor, and the height of each inert material layer 2 in the catalyst bed is 0.5 times the inner diameter of the fixed bed reactor, the uppermost layer and the lowermost layer of the catalyst bed are both inert material layer 2, the number of layers of the palladium-carbon catalyst layer 1 is not less than 3; the palladium-carbon catalyst layer 1 Consists of the following components by mass percentage: 0.8% of the active component, 0.3% of the metal auxiliary agent, the balance being the carrier, the active component is Pd, and the metal auxiliary agent is a mixture of ...

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Abstract

The invention discloses a hydrodechlorination method for producing high-purity monochloro acetic acid. The Hydrodechlorination method comprises the following steps: 1, filling a fixed bed reactor with a catalyst bed; 2, uniformly mixing hydrogen and a reaction mixed solution in a gas-liquid mixer, and injecting the obtained mixture into a heat exchanger to be pre-heated so as to obtain a reaction raw material; 3, discharging air in the fixed bed reactor by the nitrogen gas pump-in method, then discharging nitrogen gas in the fixed bed reactor by the hydrogen pump-in method, and injecting the reaction raw material into the fixed bed reactor for hydrodechlorination reaction so as to obtain an intermediate product; 4, performing distillation separation on the intermediate product to obtain monochloro acetic acid with the quality purity not less than 99.5%. The method continually and selectively conducts catalytic hydrogenation to remove dichloroacetic acid in the reaction mixed solution, inhibits formation of a by-product (acetic acid) in the intermediate product to be within an acceptable range, and reduces the mass content of dichloroacetic acid in the obtained by-products to be 0.5% or below.

Description

Technical field [0001] The invention belongs to the technical field of catalytic hydrogenation technology, and specifically relates to a method for producing high-purity monochloroacetic acid by catalytic hydrogenation and dechlorination. Background technique [0002] Chloroacetic acid is an important fine chemical product and organic chemical intermediate, and is widely used as an active compound. In the pesticide industry, chloroacetic acid can be used to synthesize more than 20 commonly used pesticides, herbicides and plant production regulators; in the pharmaceutical industry, chloroacetic acid and its esters are mainly used to prepare vitamins, hormones and other drugs; In the fuel industry, chloroacetic acid is mainly used for the synthesis of reactive dyes; in addition, chloroacetic acid is also an important organic synthesis intermediate, which can be used to prepare fine chemicals such as malonic acid, malononitrile, and malonate. Monochloroacetic acid is mainly produce...

Claims

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Application Information

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IPC IPC(8): C07C51/487C07C53/16B01J23/44B01J23/58B01J23/63B01J23/89
CPCC07C51/487B01J23/44B01J23/58B01J23/63B01J23/8906B01J23/8946C07C53/16
Inventor 陈丹李钊曾利辉曾永康张之翔王鹏宝朱柏烨林涛
Owner XIAN CATALYST NEW MATERIALS CO LTD
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