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A production process for the synthesis of pentafluoroethane by two-step gas-phase catalytic fluorination

A production process, pentafluoroethane technology, applied in the field of pentafluoroethane preparation, can solve problems such as storage and transportation difficulties, inability to meet actual production, and polymer production

Active Publication Date: 2019-12-24
福建省清流县东莹化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high cost of tetrafluoroethylene, it is not economically suitable to adopt this route, and the synthetic route uses TFE as a raw material, which is quite difficult to store and transport, and there will be safety problems such as explosion hazard and polymer generation, so this route Cannot be widely adopted in actual industrial production
[0005] Patent application CN200680043472.9 discloses a method for preparing pentafluoroethane in a single stage by perchlorethylene and HF in the gas phase in the presence of a catalyst, but the purity of pentafluoroethane produced by this method is low and cannot meet the actual requirements. The needs of production, and the catalyst life is short, the selectivity is low, it cannot be reused, and the production cost is high

Method used

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  • A production process for the synthesis of pentafluoroethane by two-step gas-phase catalytic fluorination

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] A production process for synthesizing pentafluoroethane by two-step gas-phase catalytic fluorination, comprising the steps of:

[0069] 1) The raw material PCE is preheated to 80°C through the casing heater at a rate of 500kg / h, and the HF is preheated to 80°C through a reverse initial heater (shell side) at a rate of 300kg / h. The preheated PCE and The gas-liquid mixture of HF is heated to 280°C through an anti-vaporizer, an anti-waste heat recovery heat exchanger (shell side), and an anti-heat oil heater, and then passed into the primary reactor to control the The molar ratio of HF and PCE is 4:1; the first mixed gas is discharged after being catalyzed by the fluorination catalyst in the primary reactor; the first gas mixture is HCFC-123, HCFC-124, by-product HCl, A small amount of HFC-125 and unreacted anhydrous HF and PCE;

[0070] The preparation method of fluorination catalyst is as follows:

[0071] S1 Add recovered ammonia solution with a concentration of 20% i...

Embodiment 2

[0088] A production process for synthesizing pentafluoroethane by two-step gas-phase catalytic fluorination, which differs from Example 1 only in that:

[0089] 1) The raw material PCE is preheated to 80°C through the casing heater at a rate of 500kg / h, and the HF is preheated to 80°C through a reverse initial heater (shell side) at a rate of 300kg / h. The preheated PCE and The gas-liquid mixture of HF is then heated to 280°C through an anti-vaporizer, an anti-waste heat recovery heat exchanger (shell side), and an anti-heat oil heater, and then passed into the primary reactor; The molar ratio of HF and PCE is 16:1; the first mixed gas is discharged after catalyzed fluorination by the fluorination catalyst in the primary reactor; the first gas mixture is HCFC-123, HCFC-124, by-product HCl, A small amount of HFC-125 and unreacted anhydrous HF and PCE;

[0090] The preparation method of fluorination catalyst is as follows:

[0091] S1 Add recovered ammonia solution in the disso...

Embodiment 3

[0096] A production process for synthesizing pentafluoroethane by two-step gas-phase catalytic fluorination, which differs from Example 1 only in that:

[0097] The temperature of the middle and upper part of No. 1 separation tower is 50°C, the temperature of the bottom of the tower is 70°C, and the pressure is 0.4MPa;

[0098] After testing, the content of CFC-115 in the crude product HFC-125 is 1.8%; the purity of pure pentafluoroethane is 99.2%, wherein the content of CFC-115 is 0.1%, and the selectivity of pentafluoroethane is 99% , the conversion rate of tetrachlorethylene is 99%.

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Abstract

The invention belongs to the technical field of preparation of pentafluoroethane, and specifically relates to a production process for synthesizing the pentafluoroethane through two-step gas-phase catalytic fluorination. The production process comprises the following steps: 1) with HF and PCE as raw materials, allowing the HF and the PCE to undergo a first-stage fluorination catalysis reaction ina first-stage reactor so as to obtain a first gas mixture; 2) allowing the first gas mixture to pass through a separation tower No. 1 for separation, allowing high-boiling residues at the lower part of the tower to return to the first-stage reactor to resume the reaction, and allowing low-boiling residues discharged from the top of the separation tower No. 1 to enter a separation tower No. 2; and3) allowing the high-boiling residues at the lower part of the separation tower No. 2 to enter a second-stage reactor through a separation tower No. 3 for a second-stage fluorination catalysis reaction so as to obtain a crude HFC-125 product, and purifying the low-boiling residues discharged from the top of the separation tower No. 2 by a purifying system so as to obtain a purified pentafluoroethane product. The production process for synthesizing the pentafluoroethane through two-step gas-phase catalytic fluorination provided by the invention overcomes the problems of low purity and difficultpurification of the target product HFC-125 in the prior art, and can improve the purity of the HFC-125 to 99.99%.

Description

technical field [0001] The invention belongs to the technical field of pentafluoroethane preparation, and in particular relates to a production process for synthesizing pentafluoroethane through two-step gas-phase catalytic fluorination. Background technique [0002] With the further implementation of the "Montreal Protocol on Substances that Deplete the Ozone Layer" and "China's National Plan for Phasing Out Ozone Depleting Substances", relevant companies in various countries are speeding up the pace of developing alternatives to ozone depleting substances (ODS). Pentafluoroethane (CF 3 CHF 2 , commonly known as HFC-125) is widely used in R402A, R404A, R410A, R407C and R507 because it does not damage the earth's ozone layer or has slight damage to the earth's ozone layer. 2 In addition, it is also widely used as a foaming agent, solvent, propellant, fire extinguishing agent and dry etching agent. [0003] At present, the most widely used method for the preparation of pen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C19/08C07C19/12C07C17/25C07C17/383B01J27/12
CPCB01J27/12C07C17/25C07C17/383C07C19/12C07C19/08
Inventor 张伟董国文陈凯胡建彪凌鹏王京陈涛李军国金哲亮
Owner 福建省清流县东莹化工有限公司