Novel chloroxylenol production process by high-temperature chlorination process

Abstract

The invention discloses a novel chloroxylenol production process by high-temperature chlorination process. The novel chloroxylenol production process by high-temperature chlorination process includes the steps of firstly, gasifying a certain flow of chlorinating agent, and allowing the gasified chlorinating agent to enter the lower portion of a chlorination tower; secondly, charging a certain flow of liquid material into a preheater, preheating, and allowing the heated liquid material to enter the upper portion of the chlorination tower; thirdly, allowing the preheated material coming down from the upper portion of the chlorination tower to contact with the chlorinating agent gas coming up from the lower portion of the chlorination tower, and allowing for reaction; and fourthly, subjecting the material in the chlorination tower to forced external circulation by a circulating pump, disposing a heat exchanger at an outlet of the circulating pump to adjust interior temperature of the chlorination tower, and disposing an adjusting valve on a gaseous pipeline at the top of the chlorination tower, which passes through a buffer tank, to control interior pressure of the chlorination tower. Whole reaction in the process is fully automated. Operability, environmental protection and safety of the novel production process are greatly improved as compared with those of existing production using a reactor.

Description

technical field [0001] The invention belongs to a basic chemical chlorination process, in particular to a new process for producing p-chloro-m-xylenol by a high-temperature chlorination method. Background technique [0002] p-Chloro-m-xylenol (that is, 4-chloro-3,5-dimethylphenol, referred to as PCMX) is recognized as a high-efficiency, broad-spectrum and safe fungicide, certified by the US FDA as the preferred fungicide, widely used Used in cosmetics, paints, and leather as fungicides, anti-mildew and anti-bacterial agents. Since the SARS pathogen broke out in November 2002, causing 916 deaths in the world, people have paid more and more attention to personal hygiene, which has provided a huge market for the wide application of p-chloro-m-xylenol. [0003] The industrial production of p-chloro-m-xylenol generally uses m-xylenol as a raw material, and cuprous chloride is used as a catalyst system to chlorinate with a chlorinating agent to generate p-chloro-m-xylenol. In th...

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Problems solved by technology

[0006] The process of the above two documents has the advantages of simple technology, good selectivity, and useful experiments on the chlorination reaction, but at the same time, the vapor pressure of the solvent is high, and the boiling point is low. A large amount of volatilization of the solvent in the reaction process has a greater impact on the environment. There are certain difficulties in the process of industrialization

[0007] Patent 200710034241.8 "Industrial Preparation Method of P-Chloroalkylphenol", 200910044035.4 "A Preparation Method of 1-Hydroxy-3,5-Dimethyl-4-Chlorobenzene" and Patent 201010176713.5 "A 1-Hydroxy-3 , 5-Dimethyl-4-Chlorobenzene Green Industrial Preparation Method" three patents proposed different ways to prepare p-chloro-m-xylenol, all of which will use different types of catalysts or solvents, although by adding solvents or The catalyst improves the conversion rate of the reaction, but it is also difficult to recover the catalyst, which generally needs to be discharged to the environment, and the addition of solvents, especially organic solvents, is even more harmful to operators, so they are extremely dangerous in industrial production. Great environmental pressure does not conform to the existing industrial policies of greening and clean production

In addition, since PCMX products are phenolic substances, they are easily oxidized into other substances and complexed with various metals or non-metals to form other substances, which will cause deviations in the appearance, color and clarity of the product, so adding other substances in the reaction will affect The final quality of the product has a certain negative impact

[0008] At present, there are different types of solvents such as chloroform or catalysts such as FeCl in the field of PCMX production. 3 , ZnCl 2 , AlCl 3 In other cases, because the solvent cannot be completely recovered during use, it will pollute the water quality and cause harm to the physical and mental health of long-term operators, while the utilization efficiency of the catalyst is low, which will cause metal pollution and cause varying degrees of damage to the environment.