Preparation method of 2, 3, 3, 3-tetrafluoropropene

Abstract

The invention provides a preparation method of 2, 3, 3, 3-tetrafluoropropene, which comprises the following steps: taking monochlorodifluoromethane (R22) and methane chloride (methyl chloride) as raw materials and carrying out thermal cracking reaction at a high temperature of 600-1000 DEG C under the condition that N2 exits to prepare the 2, 3, 3, 3-tetrafluoropropene, wherein the volume ratio of the monochlorodifluoromethane to the methane chloride is 1-3:1, and the retention time of a reactant is 0.01-0.2 seconds. The reaction raw material used in the preparation method is easy to obtain, the defect of high cost of the used raw material in the prior art is overcome, the production cost is greatly reduced, and the reaction process is simple. The prepared 2, 3, 3, 3-tetrafluoropropene has the advantages of zero ODP and low GWP and can be used as a substitute of an automotive air-conditioning refrigerant.

Description

technical field

[0001] The present invention relates to a preparation method of fluorinated olefin, which is a novel refrigerant with excellent performance, specifically a preparation method of 2,3,3,3-tetrafluoropropene (HFO-1234yf), which has a relatively low Greenhouse potential (low GWP), zero ozone depletion potential (zero ODP) and cause people's widespread concern, the invention belongs to chemical technical field. Background technique

[0002] In recent years, the problem of global warming has become increasingly serious, and reducing greenhouse gas emissions has become one of the focuses of global environmental protection. The "Montreal Protocol" has determined the phase-out schedule of HCFCs. At present, the substitutes of HCFCs are mainly HFCs and their mixtures, including R-32, R-134a, R-152a and so on. Although the ozone depletion potential (ODP) of HFCs is 0, it has a high greenhouse effect potential (GWP), and has been included in the annex of greenhouse gase...

Examples

Embodiment 1

[0036] A kind of preparation method of 2,3,3,3-tetrafluoropropene, difluorochloromethane (R 22 ) and monochloromethane (methyl chloride) as raw materials, cracking reaction occurs under high temperature conditions to obtain 2,3,3,3-tetrafluoropropene. The chemical reaction equation is as follows:

[0037] 2CHClF 2 +CH 3 Cl→CF 3 CF=CH 2 +3HCl

[0038] Charge 27.3 g of monochloromethane and 93.5 g of difluorochloromethane into a steel cylinder with a volume of 8 L, and then charge with 5 g of nitrogen gas for premixing.

[0039] A SUS316 stainless steel tubular reactor device with an inner diameter of 6mm and a length of 40cm is placed in a ceramic tube. The ceramic tube is wrapped with resistance wire, and is kept insulated with aluminum silicate insulation cotton. It is heated by resistance wire with a temperature controller and thermoelectric Even control the temperature required for the reaction.

[0040] Adjust the display of the temperature controller, preheat the r...

Embodiment 2

[0042] As described in Example 1, the difference is: adjust the display of the temperature controller, first preheat the reaction device, and after the temperature is stabilized at 850 ° C, feed nitrogen into the reaction device for replacement, and replace the reaction device for 3 After -5min, the reaction mixture that has been mixed is passed into the reaction device, the flow rate of the mixed gas entering the reaction device is controlled by a flow meter to be 6.78L / min, the control system pressure is 0.4MPa, and the product from the reaction device is mixed The stream is introduced into a quenching device filled with lye, and quenched to obtain a mixture stream containing 2,3,3,3-tetrafluoropropene (HFO-1234yf); sampling gas chromatography analysis shows that 2,3,3,3 - The mass fraction of tetrafluoropropene is 14.1%. After drying, the mixture stream is separated to finally obtain 2,3,3,3-tetrafluoropropene product.

Embodiment 3

[0044] As described in Example 1, the difference is: adjust the reading of the temperature controller, first preheat the reaction device, and after the temperature is stabilized at 950 ° C, feed nitrogen into the reaction device for replacement, and replace the reaction device for 3 After -5min, the reaction mixture that has been mixed is passed into the reaction device; other steps are the same as in Example 1. The mixture stream was sampled and analyzed by gas chromatography, and the mass fraction of 2,3,3,3-tetrafluoropropene in the mixed product was 13.2%.

technical field

[0001] The present invention relates to a preparation method of fluorinated olefin, which is a novel refrigerant with excellent performance, specifically a preparation method of 2,3,3,3-tetrafluoropropene (HFO-1234yf), which has a relatively low Greenhouse potential (low GWP), zero ozone depletion potential (zero ODP) and cause people's widespread concern, the invention belongs to chemical technical field. Background technique

[0002] In recent years, the problem of global warming has become increasingly serious, and reducing greenhouse gas emissions has become one of the focuses of global environmental protection. The "Montreal Protocol" has determined the phase-out schedule of HCFCs. At present, the substitutes of HCFCs are mainly HFCs and their mixtures, including R-32, R-134a, R-152a and so on. Although the ozone depletion potential (ODP) of HFCs is 0, it has a high greenhouse effect potential (GWP), and has been included in the annex of greenhouse gase...

Examples

Embodiment 1

[0036] A kind of preparation method of 2,3,3,3-tetrafluoropropene, difluorochloromethane (R 22 ) and monochloromethane (methyl chloride) as raw materials, cracking reaction occurs under high temperature conditions to obtain 2,3,3,3-tetrafluoropropene. The chemical reaction equation is as follows:

[0037] 2CHClF 2 +CH 3 Cl→CF 3 CF=CH 2 +3HCl

[0038] Charge 27.3 g of monochloromethane and 93.5 g of difluorochloromethane into a steel cylinder with a volume of 8 L, and then charge with 5 g of nitrogen gas for premixing.

[0039] A SUS316 stainless steel tubular reactor device with an inner diameter of 6mm and a length of 40cm is placed in a ceramic tube. The ceramic tube is wrapped with resistance wire, and is kept insulated with aluminum silicate insulation cotton. It is heated by resistance wire with a temperature controller and thermoelectric Even control the temperature required for the reaction.

[0040] Adjust the display of the temperature controller, preheat the r...

Embodiment 2

[0042] As described in Example 1, the difference is: adjust the display of the temperature controller, first preheat the reaction device, and after the temperature is stabilized at 850 ° C, feed nitrogen into the reaction device for replacement, and replace the reaction device for 3 After -5min, the reaction mixture that has been mixed is passed into the reaction device, the flow rate of the mixed gas entering the reaction device is controlled by a flow meter to be 6.78L / min, the control system pressure is 0.4MPa, and the product from the reaction device is mixed The stream is introduced into a quenching device filled with lye, and quenched to obtain a mixture stream containing 2,3,3,3-tetrafluoropropene (HFO-1234yf); sampling gas chromatography analysis shows that 2,3,3,3 - The mass fraction of tetrafluoropropene is 14.1%. After drying, the mixture stream is separated to finally obtain 2,3,3,3-tetrafluoropropene product.

Embodiment 3

[0044] As described in Example 1, the difference is: adjust the reading of the temperature controller, first preheat the reaction device, and after the temperature is stabilized at 950 ° C, feed nitrogen into the reaction device for replacement, and replace the reaction device for 3 After -5min, the reaction mixture that has been mixed is passed into the reaction device; other steps are the same as in Example 1. The mixture stream was sampled and analyzed by gas chromatography, and the mass fraction of 2,3,3,3-tetrafluoropropene in the mixed product was 13.2%.