Method for synthesizing 1,1,2,2-tetrafluoroethane

A technology of HCFC-22 and mixed gas, which is applied in chemical instruments and methods, catalyst carriers, organic chemistry, etc., can solve the problems of affecting the service life of the catalyst, difficulty in regeneration, and reduction of the specific surface area of ​​the catalyst, so as to be suitable for technological production, Easy to regenerate and recycle, the effect of temperature stability

Active Publication Date: 2009-12-02
泉州宇极新材料科技有限公司
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  • Abstract
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Problems solved by technology

However, after the catalyst with activated carbon as the carrier is deactivated, it is difficult to regenerate and cannot be regenerated with oxygen.
When alumina is used as a carrier, HF generated during hydrogenation will react with alumina to form AlF 3 , so that the specific surface area of ​​the catalyst is reduced, which in turn affects the service life of the catalyst

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  • Method for synthesizing 1,1,2,2-tetrafluoroethane

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preparation example Construction

[0019] In the present invention, HCFC-22 pyrolysis generates unreacted HCFC-22 in the mixed gas product as an inert component (the inert component can also be any gas that does not react with TFE and hydrogen under reaction conditions such as nitrogen, Including the HCFC-22 gas that feeds in simultaneously with the TFE gas), take away the heat generated by the reaction, and can keep the catalytic reaction stably carried out. The synthesis method includes the following steps:

[0020] Weigh a certain amount of active catalyst and dissolve it in dilute acid, add a certain amount of carrier, soak for a period of time to remove water, and then dry the catalyst for use.

[0021] Load the catalyst into the reactor, N 2 After further removal of water under conditions, the H 2 Activate the catalyst, then pass the mixed gas containing TFE and H 2 The reaction was carried out to obtain the target object HFC-134.

[0022] Experimental implementation 1-9 describes the present invention...

Embodiment 1

[0024] Catalyst preparation: wash 100 g of carrier aluminum fluoride with distilled water and dry in an oven at 120°C for 2 hours. Dissolve 1.7 g of the weighed active ingredient palladium chloride with dilute hydrochloric acid, then add the dried carrier and let stand overnight. After standing still, treat with a rotary evaporator, adjust the rotary evaporator to evaporate to dryness under reduced pressure at 80°C, 0.3atm, 120r / min, and store in a dry place.

[0025] Activation: Load the catalyst prepared in the previous step into the reactor, adjust the nitrogen flow rate to 30ml / min, raise the temperature to 250°C, and keep it for 2h. Then pass H2 and N2 mixed gas, keep 4h.

[0026] Reaction: After the catalyst activation is completed, the reaction temperature is adjusted to 210° C., and 200 ml / min of mixed gas of HCFC-22 and TFE (the molar ratio is 50:50) and 200 ml / min of hydrogen are introduced. After the reaction, the gas is washed with water, washed with alkali and t...

Embodiment 2

[0028] Catalyst preparation: Wash 100 g of carrier magnesium fluoride with distilled water and dry in an oven at 120°C for 2 hours. Dissolve 2.6 g of the weighed active ingredient palladium chloride with dilute hydrochloric acid, then add the dried carrier and let stand overnight. After standing still, treat with a rotary evaporator, adjust the rotary evaporator to evaporate to dryness under reduced pressure at 80°C, 0.3atm, 120r / min, and store in a dry place.

[0029] Catalyst activation was as the catalyst activation process in Example 1.

[0030] Reaction: After the catalyst activation is completed, the reaction temperature is adjusted to 250° C., and 200 ml / min of mixed gas of HCFC-22 and TFE (the molar ratio is 50:50) and 200 ml / min of hydrogen are introduced. After the reaction, the gas is washed with water, washed with alkali and then dried, and detected by gas chromatography.

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Abstract

The invention relates to a method for synthesizing 1,1,2,2-tetrafluoroethane, which belongs to the field of preparation of refrigerants. TFE-containing mixed gas and hydrogen pass through a porous carrier supported hydrogenation catalyst bed to generate HFC-134; the TFE-containing mixed gas is a mixture formed by TFE and inert gas; the inert gas is gas which does not react with the TFE and the hydrogen under reaction conditions; and a porous carrier material is fluoride or oxyfluoride. An inert component in the method does not participate in the reaction, but can take away the heat generated by the reaction to ensure that the temperature of the catalyst bed is relatively steady and the service life of a catalyst is prolonged; and the adopted porous carrier is the fluoride or the oxyfluoride, does not react with hydrogen fluoride removed during the reaction, improves the service life of the catalyst and is easy to recycle at the same time. The synthesis method has good stability and safe synthesis process, and is suitable for technologized production.

Description

technical field [0001] The invention relates to the field of refrigerant preparation, in particular to a method for synthesizing 1,1,2,2-tetrafluoroethane (CHF 2 CHF 2 )Methods. Background technique [0002] 1,1,2,2-Tetrafluoroethane (HFC-134) has been recognized by the United Nations Environment Program as a mid- to long-term substitute for difluorodichloromethane (CFC-12). HFC-134 is an isomer of 1,1,1,2-tetrafluoroethane (HFC-134a), with a refrigeration coefficient (COP value) of 3.84, which is higher than that of HFC-134a and CFC-12. And it has almost all the advantages of HFC-134a. The mixture of HFC-134 and CFC-152 has a good cooling effect, and its ODP value is 0, and its GWP value is also relatively low. Therefore, HFC-134 has great performance advantages for ordinary household refrigerators and air-conditioning refrigeration refrigerants. and use potential. At the same time, as the basic raw material of the new freon-substituting refrigeration mixed working med...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C19/08C07C17/354B01J32/00B01J27/12B01J27/06
Inventor 杨光成贾晓卿郭艳红刘冬明鲍鹏
Owner 泉州宇极新材料科技有限公司
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