High-efficiency catalyst for producing chloroform by gas phase hydrogenation of carbon tetrachloride

Abstract

The invention relates to a high-efficiency catalyst for producing chloroform by gas phase hydrogenation of carbon tetrachloride. The high-efficiency catalyst is mainly characterized in that the activeingredient platinum is distributed in a thick-shell layer permeation form on a carrier alumina. According to the catalyst, the precious metal platinum serves as the active ingredient, the introduction amount of the platinum is 0.1-1% of the total mass of the carrier, the carrier is alumina of being spherical, strip-shaped or in the other shapes, and the carrier is pre-treated by adopting an organic acid competitive adsorbent, so that the active ingredient platinum is distributed in the thick-shell layer permeation form on the carrier. Compared with a catalyst without being subjected to organic acid pretreatment, the catalyst has high activity, conversion rate and selectivity under the same operating conditions, capable of effectively reducing the production of harmful conjugate impuritiessuch as hexachloroethane and tetrachloroethylene, and has long service life. The catalyst is applied to industrial production, and when the transformation capacity of the carbon tetrachloride is maintained at 40-50Kg / day.Kg, the catalyst can be continuously operated by 180 days or longer, and the transformation rate and selectivity are respectively maintained at 98% or 70% or higher.

Description

technical field [0001] The invention relates to a catalyst, in particular to a high-efficiency catalyst for producing chloroform by gas-phase hydrodechlorination of carbon tetrachloride. Background technique [0002] Carbon tetrachloride is a colorless, clear and transparent liquid with an aromatic odor. Its molecular structure is highly stable, and its lifetime in the atmosphere is about 42 years. The impact of carbon tetrachloride on the environment is reflected in its extremely destructive effect on the ozone layer, so the international community formulated the "Montreal Protocol on Substances that Deplete the Ozone Layer" (abbreviated "Montreal Convention") in 1989. According to the "Montreal Convention", carbon tetrachloride has been restricted in sale and banned as a solvent in 2010. However, in the current production route of methane chloride, the occurrence of carbon tetrachloride as a by-product cannot be avoided, so how to effectively treat carbon tetrachloride is...

AI Technical Summary

Problems solved by technology

However, in the current production route of methane chloride, carbon tetrachloride cannot be avoided as a by-product, so how to effectively treat carbon tetrachloride is a very important part in the production of methane chloride

[0003] Carbon tetrachloride is directly treated as waste by combustion method, but this method will produce highly toxic substance phosgene, which will not only cause secondary pollution to the environment, but also further increase production costs

The conversion of carbon tetrachloride into chloroform has two kinds of gas phase method and liquid phase method. The conversion of liquid phase method is difficult to realize industrialization due to the problems of easy deactivation of catalyst, difficult regeneration and harsh reaction conditions.

The problem with this reaction is that the reaction selectivity is low and the activity of the catalyst decreases rapidly in a short time.

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