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Method for producing tetrafluoromethane by gas phase catalysis

A technology for tetrafluoromethane and chlorotrifluoromethane, which is applied in the field of gas-phase catalytic production of tetrafluoromethane, can solve the problems of low reaction temperature, low single-pass conversion rate, low single-pass conversion rate, and high reaction temperature, and achieves reduced equipment investment and selectivity. Effects of high, high economic value

Inactive Publication Date: 2010-06-09
ZHEJIANG NORMAL UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] The purpose of the present invention is to provide a low required reaction temperature and high single-pass conversion rate for the disadvantages of high required reaction temperature and low single-pass conversion rate in the existing gas-phase fluorination process for producing FC-14. A cost-effective method for the gas-phase catalytic production of tetrafluoromethane

Method used

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  • Method for producing tetrafluoromethane by gas phase catalysis
  • Method for producing tetrafluoromethane by gas phase catalysis
  • Method for producing tetrafluoromethane by gas phase catalysis

Examples

Experimental program
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Effect test

Embodiment 1

[0029] First, weigh Cr according to the molar ratio between Cr and Al is 1:4 2 o 3 and Al(OH) 3 , mix evenly with an appropriate amount of water, add a certain amount of ammonia water until the precipitation is complete, then separate and wash until the filtrate is neutral, and then dry the precipitate at 70°C. After the dried precipitate was molded, it was heated at 300°C and N 2 Calcined in the atmosphere for 48 hours to obtain a fluorinated catalyst precursor. The fluorination catalyst precursor was treated with HF at 250° C. for 48 hours to obtain a fluorination catalyst.

[0030] A certain amount of the obtained fluorination catalyst is loaded into the reactor, the reaction temperature is 300° C., the molar ratio of chlorotrifluoromethane and HF is 1:1 mixed gas, and the contact time between the mixed gas and the catalyst is 30 seconds; The gas is separated and processed by the separation tower, and HF is recovered from the bottom fraction and sent to the reactor as f...

Embodiment 2

[0033] First, weigh Cr(OH) according to the molar ratio between Cr and Al of 1:19 3 and Al(NO 3 ) 3 , mix well with an appropriate amount of water, add a certain amount of Na 2 CO 3 After the precipitation is complete, it is separated and washed until the filtrate is neutral, and then the precipitate is dried at 120°C. After the dried precipitate was molded, it was heated at 600°C and N 2 Calcined in the atmosphere for 24 hours to obtain a fluorinated catalyst precursor. The fluorination catalyst precursor was treated with HF at 400° C. for 30 hours to obtain a fluorination catalyst.

[0034]A certain amount of the obtained fluorination catalyst is loaded into the reactor, the reaction temperature is 400° C., the molar ratio of dichlorodifluoromethane and HF is 1:10 mixed gas, and the contact time between the mixed gas and the catalyst is 2 seconds; The gas adopts the same treatment method as in Example 1. See Table 1 for the single-pass conversion rate of raw materials...

Embodiment 3

[0036] First, weigh CrCl according to the molar ratio between Cr and Al of 1:3 3 and Al 2 o 3 , mix evenly with an appropriate amount of water, add a certain amount of KOH until the precipitation is complete, then separate and wash until the filtrate is neutral, and then dry the precipitate at 90°C. The dried precipitate is shaped and calcined at 400° C. in an air atmosphere for 36 hours to obtain a fluorination catalyst precursor. The fluorination catalyst precursor was treated with HF at 350° C. for 35 hours to obtain a fluorination catalyst.

[0037] A certain amount of the obtained fluorination catalyst is loaded into the reactor, the reaction temperature is 360° C., the molar ratio of trichlorofluoromethane and HF is 1:6 mixed gas, and the contact time between the mixed gas and the catalyst is 10 seconds; The gas adopts the same treatment method as in Example 1. See Table 1 for the single-pass conversion rate of raw materials and the selectivity to FC-14.

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Abstract

The invention discloses a method for producing a tetrafluoromethane by gas phase catalysis. Aiming at the defects of high needed reaction temperature and low conversion per pass existing in the conventional process for producing FC-14 by gas phase fluorination, the invention provides an economic and high-efficient method for producing the tetrafluoromethane by gas phase catalysis, which has the advantages of low needed reaction temperature and high conversion per pass. The method for producing the tetrafluoromethane comprises the following step: reacting halohydrocarbon with hydrogen fluoride at the presence of a gas phase fluorination catalyst in a gas phase to produce the tetrafluoromethane, wherein the molar ratio of the halohydrocarbon to the hydrogen fluoride is 1:1-10; the halohydrocarbon is one or more of the tetrafluoromethane, trichloromonofluomethane, dichlorodifluoromethane and monochlorotrifluoromethane; the used gas phase fluorination catalyst adopts a chromium compound as an active component and an aluminum compound as a carrier; and the molar ratio of the chromium to the aluminum is 1:1-19. The method for producing the tetrafluoromethane has the characteristics of long service life and high percent conversion of the halohydrocarbon.

Description

technical field [0001] The invention relates to a method for producing tetrafluoromethane, in particular to a method for gas-phase catalytic production of tetrafluoromethane. Background technique [0002] Tetrafluoromethane (hereinafter referred to as FC-14) is a very useful compound in industry. For example, it is currently the most used plasma etching gas in the microelectronics industry. The mixed gas of oxygen can be widely used in the etching of thin film materials such as silicon, silicon dioxide, silicon nitride, phosphosilicate glass and tungsten; it can be used for surface cleaning of electronic devices, production of solar cells, laser technology, gas phase insulation, ultra-low temperature refrigeration Agents, leak detection agents, detergents, metal smelting and plastic industries are also widely used. [0003] In order to produce FC-14, various methods have been proposed so far. At present, there are mainly the following methods for preparing FC-14 in industr...

Claims

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Application Information

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IPC IPC(8): C07C19/08C07C17/20C07C17/21
Inventor 罗孟飞钱林鲁继青邢丽琼毕庆员周黎旸陈科峰张学良严孝忠
Owner ZHEJIANG NORMAL UNIVERSITY
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