Disclosure of Invention
The invention aims to provide a method for preparing 2,3,3, 3-tetrafluoropropene with relatively mild reaction conditions, simple equipment operation and high conversion rate aiming at the defects of the existing 2,3,3, 3-tetrafluoropropene preparation technology, and chloroethylene and CCl4Is used as a raw material, and an industrial chain is formed in the reaction process through a plurality of reaction steps, so that the method has a good industrial application prospect.
In order to solve the technical problems, the invention adopts the following technical scheme:
a preparation method of 2,3,3, 3-tetrafluoropropene is characterized by comprising the following steps:
(1) mixing CCl4And chloroethylene are telomerized to generate 1,1,1,3, 3-pentachloropropane;
(2) dehydrochlorinating the 1,1,1,3, 3-pentachloropropane obtained in the previous step to produce 1,1,3, 3-tetrachloro-1-propene;
(3) carrying out fluorine-chlorine exchange and dehydrochlorination on the 1,1,3, 3-tetrachloro-1-propylene obtained in the previous step under the catalytic condition to prepare 3,3, 3-trifluoro-1-chloropropene;
(4) isomerizing the fluorine liquid phase of the 3,3, 3-trifluoro-1-chloropropene obtained in the previous step into 3,3, 3-trifluoro-2-chloropropene;
(5) fluorinating the 3,3, 3-trifluoro-2-chloropropene obtained in the previous step into 1,1,1, 2-tetrafluoro-2-chloropropane in a liquid phase;
(6) dehydrochlorination of the 1,1,1, 2-tetrafluoro-2-chloropropane obtained in the previous step to produce 2,3,3, 3-tetrafluoropropene.
Preferably, in step (1), CCl4And chloroethylene are subjected to free radical addition reaction under the action of a catalyst to synthesize the 1,1,1,3, 3-pentachloropropane, wherein the main catalyst is an iron compound, the iron compound comprises iron powder, the cocatalyst is an alkyl phosphate compound, an alkyl phosphite compound or a composition thereof, and the alkyl phosphate compound or the alkyl phosphite compound comprises one or more of dibutyl phosphate, tributyl phosphate, triethyl phosphite, tributyl phosphite, tripropyl phosphite and triisobutyl phosphite.
Preferably, in step (1), CCl4The mol ratio of the vinyl chloride to the vinyl chloride is 10: 1-10, preferably 10: 1-6, and more preferably 10: 1-4; the amount of the main catalyst accounts for 0.1-3% of the total material mass, preferably 0.5-1%, the molar weight ratio of the auxiliary catalyst to the main catalyst is 1: l, the reaction temperature is 30-200 ℃, preferably 50-150 ℃, more preferably 80-120 ℃, the reaction time is 3-10 h, preferably 4-5 h, and the reaction pressure is 2-10 bar, preferably 2-8 bar, more preferably 2-4 bar.
Preferably, in the step (2), the dehydrochlorination of 1,1,1,3, 3-pentachloropropane is carried out in contact with a base, the base-mediated dehydrochlorination process may be carried out in the presence or absence of a solvent, the solvent comprises water, the base comprises an alkali metal hydroxide selected from lithium hydroxide, sodium hydroxide and potassium hydroxide, more preferably selected from sodium hydroxide and potassium hydroxide, and most preferably potassium hydroxide, and the weight of the base is 10 to 50 wt%, preferably 15 to 30 wt%, of the total weight of all components in the step (2); the reaction temperature in the dehydrochlorination process is 0-300 ℃, preferably 50-200 ℃, more preferably 130-145 ℃, the reaction time is 1-100 hours, preferably 2-20 hours, more preferably 3-8 hours, and the reaction pressure is 3-5 bar.
Preferably, in step (3), the catalyst comprises trifluoroacetic acid, trifluoromethanesulfonic acid and TiCl4、TiF4、SnCl4、SnF4、SbF5、SbCl5、CsF、SbFxCly(x + y ═ 5) of one or more mixtures; the molar ratio of the anhydrous HF to the 1,1,3, 3-tetrachloro-1-propene is 1-50: 1, preferably 10-30: 1, more preferably 15-20: 1; the reaction temperature of the fluorine-chlorine exchange and dehydrochlorination reaction is 100-250 ℃, preferably 140-200 ℃, the reaction time is 2-10 hours, preferably 5-8 hours, and the reaction pressure is 0.5-10 bar, preferably 1-5 bar, and more preferably 2.7-3.4 bar.
Preferably, in the step (4), the catalyst used for the liquid phase isomerization reaction comprises the following two types: AlF3、TiF4、TaF5、NbF5、MoF6、SnF4、SbF5、SbFxCly(x + y ═ 5) and one or more ionic liquids; bronsted acids or sulfonic acids (e.g. ClSO)3H、FSO3H、CF3SO3H、CH3SO3H) One or more of the components are mixed; the weight of the catalyst is 5-20 wt% of all the raw materials in the step (4), preferably 10-20 wt%; the reaction temperature of the liquid phase isomerization reaction is 20-300 ℃, preferably 80-200 ℃, more preferably 140-180 ℃, the reaction time is 0.5-50 h, preferably 4-20 h, more preferably 6-10 h, and the reaction pressure is 0.1-6 bar, preferably 2-3.5 bar.
Preferably, in the step (5), the reaction temperature of the liquid phase fluorination reaction is 80-120 ℃, the reaction time is 2-10 h, preferably 5-8 h, the reaction pressure is 5-8 bar, and the catalyst is SbF3/SbCl5Or La-ZnO/Cr2O3,SbF3/SbCl5In the mixed catalyst system of (1), Sb5+And Sb3+The mass ratio of the substances is 1:1, La-ZnO/Cr2O3In the mixed catalyst system, the La content is ZnO and Cr2O31.5-2 wt%, and the mass ratio of Zn and Cr is 1: 5.
Preferably, in the step (6), the dehydrochlorination reaction is performed in a water-KOH mixture, KOH accounts for 10-50 wt% of the mixture, preferably KOH accounts for 20-35 wt% of the mixture, the reaction temperature is higher than 120 ℃, preferably the temperature is 130-145 ℃, the reaction time is 1-20 h, preferably 5-15 h, more preferably 5-10 h, and the reaction pressure is 1-20 bar, preferably 5-10 bar.
Preferably, steps (1) to (6) are continuous liquid phase reactions and the product streams from steps (1) to (4) are sent directly to the next step.
Preferably, the preparation method can be carried out continuously or independently, the product can be purified after each step is finished, and the products of each step are collected to form a complete industrial chain.
Due to the adoption of the technical scheme, the invention has the following beneficial effects:
the method has the advantages that the raw materials are low in price and easy to obtain, the raw material cost in the production process of the 2,3,3, 3-tetrafluoropropene is reduced, an industrial chain is formed in the reaction process, and each intermediate product has high economic value after being purified. The method has the advantages of relatively mild reaction conditions, simple equipment operation, higher raw material conversion rate and product selectivity in each reaction stage, less by-products and larger industrial application prospect.
Detailed Description
The present invention will be further described with reference to the following examples.
As shown in the flow chart of FIG. 1, with vinyl chloride and CCl4Synthesizing 1,1,1,3, 3-pentachloropropane (pentachloropropane) by free radical addition reaction under the action of a catalystHCC-240 fa), 1,1,1,3, 3-pentachloropropane (HCC-240 fa) is subjected to dehydrochlorination process under the contact of alkali to generate 1,1,3, 3-tetrachloro-1-propene (HCC-1230zd), 1,1,3, 3-tetrachloro-1-propene (HCC-1230zd) is subjected to fluorine-chlorine exchange and dehydrochlorination under the catalytic condition to prepare 3,3, 3-trifluoro-1-chloropropene (HFO-1233zd), 3,3, 3-trifluoro-1-chloropropene (HFO-1233zd) is isomerized into 3,3, 3-trifluoro-2-chloropropene (HFO-1233xf) under the action of a catalyst, 3, 3-trifluoro-2-chloropropene (HFO-1233xf) is subjected to liquid phase fluorination reaction under the action of the catalyst to synthesize 1,1,1, 2-tetrafluoro-2-chloropropane (HFC-244bb), and finally removing HCl to generate 2,3,3, 3-tetrafluoropropene (HFO-1234 yf).
Example 1
(1) Preparation of 1,1,1,3, 3-pentachloropropane
Will 1320gCCl4Adding the mixture into a 5L stainless steel high-pressure reaction kettle I, adding 30g of iron powder and 142.7g of tributyl phosphate into the reaction kettle, and sealing the reaction kettle; slowly adding CH into the reaction kettle under the control of a gas mass flowmeter2CHCl 520g, autoclave pressure through N2And CH2CHCl self-regulation; the temperature of the reaction kettle is raised to 80 ℃, the pressure is controlled to be 2bar, the reaction is stirred for 3 hours under the condition, and 1527.1g of 1,1,1,3, 3-pentachloropropane is obtained after the reaction is finished.
(2) Preparation of 1,1,3, 3-tetrachloro-1-propene
Adding 700g of 80% KOH solution and 1527.1g of 1,1,1,3, 3-pentachloropropane into a 5L hastelloy high-pressure reaction kettle II, and allowing the mixture to pass through N2Controlling the pressure of the reaction kettle; the pressure of the reaction kettle is controlled to be 3bar, the temperature is controlled to be 80 ℃, the reaction is stirred for 2 hours under the condition, and 1034.5g of 1,1,3, 3-tetrachloro-1-propene is collected after the reaction.
(3) Preparation of 3,3, 3-trifluoro-1-chloropropene
1034.5g of 1,1,3, 3-tetrachloro-1-propene were charged into a polytetrafluoroethylene-lined stainless steel autoclave III, and 51.7g of TiCl was fed through a mass flow meter41982g of liquid anhydrous HF is conveyed to the reaction kettle through an HF feeding pump; the pressure of the reaction kettle is controlled to be 1bar by nitrogen, and the reaction is stirred for 2 hours at the temperature of 100 ℃ to obtain 533.6g of 1-chloro-3, 3, 3-trifluoropropene.
(4) Preparation of 3,3, 3-trifluoro-2-chloropropene
53.4g SnF were added to a 2L Monel autoclave IV4533.6g of 1-chloro-3, 3, 3-trifluoropropene are slowly added into the reaction kettle under the control of a gas flow meter; the temperature of the reaction kettle is raised to 80 ℃, the pressure of the reaction kettle is controlled to be 1bar, and 451.7g of 2-chloro-3, 3, 3-trifluoropropene is obtained after stirring and reacting for 1h under the condition.
(5) Preparation of 1,1,1, 2-tetrafluoro-2-chloropropane
To a 2L Monel autoclave V was added 45.2g of SbF3/SbCl5As catalyst, 451.7g of 2-chloro-3, 3, 3-trifluoropropene were added into the reactor through a mass flow meter, 120g of anhydrous HF was fed into the reactor through an HF feed pump, and N was used2Controlling the pressure of the reaction kettle to be 2bar, heating the reaction kettle to 80 ℃, and stirring and reacting for 2h under the condition to synthesize 480.2g of 2-chloro-1, 1,1, 2-tetrafluoropropane.
(6) Preparation of 2,3,3, 3-tetrafluoropropene
200g of 80% KOH solution and 480.2g of 2-chloro-1, 1,1, 2-tetrafluoropropane are added into a 2L hastelloy material high-pressure reaction kettle VI for HCl removal reaction. The reaction temperature is 120 ℃, the pressure is 1bar, and the stirring reaction is carried out for 1h, thereby obtaining 293.3g of 2,3,3, 3-tetrafluoropropene.
The total conversion of the reaction was 27.2%, and the yield of 2,3,3, 3-tetrafluoropropene was 56.4% (as CH)2CHCl).
Example 2
(1) Preparation of 1,1,1,3, 3-pentachloropropane
Will 1320gCCl4Adding the mixture into a 5L stainless steel high-pressure reaction kettle I, adding 37.2g of iron powder and 176.9g of tributyl phosphate into the reaction kettle, and sealing the reaction kettle; slowly adding CH into the reaction kettle under the control of a gas mass flowmeter2CHCl 520g, autoclave pressure through N2And CH2CHCl self-regulation; the temperature of the reaction kettle is raised to 120 ℃, the pressure is controlled to be 4bar, the reaction is stirred for 5 hours under the condition, and 1619.8g of 1,1,1,3, 3-pentachloropropane is obtained after the reaction is finished.
(2) Preparation of 1,1,3, 3-tetrachloro-1-propene
694.2g of 80% KOH solution, 1619.8g of 1,1,1,3, 3-pentachloropropane are added into a 5L Hawski alloy autoclave II, and the mixture is passed through N2Controlling the pressure of the reaction kettle; the pressure of the reaction kettle is controlled to be 4bar, the temperature is controlled to be 140 ℃, the reaction is stirred for 8 hours under the condition, and 1212.1g of 1,1,3, 3-tetrachloro-1-propene is collected after the reaction.
(3) Preparation of 3,3, 3-trifluoro-1-chloropropene
1212.1g of 1,1,3, 3-tetrachloro-1-propene were charged into a tetrafluoro-lined stainless steel autoclave III, and 121.2g of SbCl was charged through a mass flow meter5Conveying 2292g of liquid anhydrous HF to the reaction kettle through an HF feed pump; the pressure of the reaction kettle is controlled to be 3bar by nitrogen, and the reaction is stirred for 6 hours at 150 ℃ to obtain 687.1g of 1-chloro-3, 3, 3-trifluoropropene.
(4) Preparation of 3,3, 3-trifluoro-2-chloropropene
68.7g of SbF were placed in a 2L Monel autoclave IV5687.1g of 1-chloro-3, 3, 3-trifluoropropene are slowly added into the reaction kettle under the control of a gas flow meter; the temperature of the reaction kettle is raised to 150 ℃, the pressure of the reaction kettle is controlled to be 3bar, and after stirring reaction is carried out for 8 hours under the condition, 549.7g of 2-chloro-3, 3, 3-trifluoropropene is obtained.
(5) Preparation of 1,1,1, 2-tetrafluoro-2-chloropropane
55g of SbF were placed in a 2L Monel autoclave V3/SbCl5Taking the mixture as a catalyst, adding 549.7g of 2-chloro-3, 3, 3-trifluoropropene into a reaction kettle through a mass flow meter, conveying 160g of anhydrous HF liquid into the reaction kettle through an HF feed pump, and using N2Controlling the pressure of the reaction kettle to be 8bar, heating the reaction kettle to 120 ℃, and stirring and reacting for 8 hours under the condition to synthesize 570.5g of 2-chloro-1, 1,1, 2-tetrafluoropropane.
(6) Preparation of 2,3,3, 3-tetrafluoropropene
244.5g of 80% KOH solution and 570.5g of 2-chloro-1, 1,1, 2-tetrafluoropropane are added into a 2L hastelloy material high-pressure reaction kettle VI for HCl removal reaction. The reaction temperature was 130 ℃ and the pressure was 10bar, and the reaction was carried out with stirring for 10 hours to obtain 367.4g of 2,3,3, 3-tetrafluoropropene.
The total conversion rate of the reaction was 38.7%The yield of 2,3,3, 3-tetrafluoropropene is 70.65% (by CH)2CHCl).
Example 3
(1) Preparation of 1,1,1,3, 3-pentachloropropane
Will 1320gCCl4Adding the mixture into a 5L stainless steel high-pressure reaction kettle I, adding 40g of iron powder and 190.2g of tributyl phosphate into the reaction kettle, and sealing the reaction kettle; slowly adding CH into the reaction kettle under the control of a gas mass flowmeter2CHCl 520g, autoclave pressure through N2And CH2CHCl self-regulation; the temperature of the reaction kettle is raised to 100 ℃, the pressure is controlled to be 3bar, the reaction is stirred for 4 hours under the condition, and 1632.2g of 1,1,1,3, 3-pentachloropropane is obtained after the reaction is finished.
(2) Preparation of 1,1,3, 3-tetrachloro-1-propene
650g of 80% NaOH solution, 1632.2g of 1,1,1,3, 3-pentachloropropane, are added into a 5L Hawthorn alloy high-pressure reaction kettle II and are passed through N2Controlling the pressure of the reaction kettle; the pressure of the reaction kettle is controlled to be 5bar, the temperature is controlled to be 130 ℃, the reaction is stirred for 6 hours under the condition, and 1285.3g of 1,1,3, 3-tetrachloro-1-propene is collected after the reaction.
(3) Preparation of 3,3, 3-trifluoro-1-chloropropene
1285.3g of 1,1,3, 3-tetrachloro-1-propene are added into a stainless steel high-pressure reaction kettle III lined with tetrafluoro, and 200g of TiF is added through a mass flow meter4Conveying 2321g of liquid anhydrous HF to the reaction kettle through an HF feed pump; the pressure of the reaction kettle is controlled to be 3bar by nitrogen, and the reaction is stirred for 8 hours at 160 ℃ to obtain 702.1g of 1-chloro-3, 3, 3-trifluoropropene.
(4) Preparation of 3,3, 3-trifluoro-2-chloropropene
140g of SbF were added to a 2L Monel autoclave IV5702.1g of 1-chloro-3, 3, 3-trifluoropropene is slowly added into the reaction kettle under the control of a gas flow meter; the temperature of the reaction kettle is raised to 150 ℃, the pressure of the reaction kettle is controlled to be 3.5bar, and 572.3g of 2-chloro-3, 3, 3-trifluoropropene is obtained after stirring and reacting for 10h under the condition.
(5) Preparation of 1,1,1, 2-tetrafluoro-2-chloropropane
To 2L of Monel alloy100g of SbF was added to autoclave V3/SbCl5As catalyst, 572.3g of 2-chloro-3, 3, 3-trifluoropropene were added into the reactor through a mass flow meter, 140g of anhydrous HF was fed into the reactor through an HF feed pump, and N was used2Controlling the pressure of the reaction kettle to be 8bar, heating the reaction kettle to 100 ℃, and stirring and reacting for 6h under the condition to synthesize 593.2g of 2-chloro-1, 1,1, 2-tetrafluoropropane.
(6) Preparation of 2,3,3, 3-tetrafluoropropene
260g of 80% KOH solution and 570.5g of 2-chloro-1, 1,1, 2-tetrafluoropropane are added into a 2L hastelloy material high-pressure reaction kettle VI for HCl removal reaction. The reaction temperature was 145 ℃ and the pressure was 10bar, and the reaction was carried out with stirring for 10 hours to obtain 380.1g of 2,3,3, 3-tetrafluoropropene.
The total conversion of the reaction was 40.3%, and the yield of 2,3,3, 3-tetrafluoropropene was 73.1% (as CH)2CHCl).
Example 4
(1) Preparation of 1,1,1,3, 3-pentachloropropane
Will 1320gCCl4Adding the mixture into a 5L stainless steel high-pressure reaction kettle I, adding 50g of iron powder and 83g of triethyl phosphite into the reaction kettle, and sealing the reaction kettle; slowly adding CH into the reaction kettle under the control of a gas mass flowmeter2CHCl 520g, autoclave pressure through N2And CH2CHCl self-regulation; and (3) raising the temperature of the reaction kettle to 150 ℃, controlling the pressure to be 8bar, stirring and reacting for 8 hours under the condition, and obtaining 1547.3g of 1,1,1,3, 3-pentachloropropane after the reaction is finished.
(2) Preparation of 1,1,3, 3-tetrachloro-1-propene
680g of 80% NaOH solution, 1547.3g of 1,1,1,3, 3-pentachloropropane are added into a 5L Hakholdham alloy high-pressure reaction kettle II and are subjected to N reaction2Controlling the pressure of the reaction kettle; the pressure of the reaction kettle is controlled to be 5bar, the temperature is controlled to be 160 ℃, the reaction is stirred for 12 hours under the condition, and 1133g of 1,1,3, 3-tetrachloro-1-propylene is collected after the reaction.
(3) Preparation of 3,3, 3-trifluoro-1-chloropropene
1133g of 1,1,3, 3-tetrachloro-1-propylene is added into a stainless steel high-pressure reaction kettle III with tetrafluoro lining, 226.6g of CsF is added through a mass flow meter, and 2300g of anhydrous HF is conveyed into the reaction kettle through an HF feed pump; the pressure of the reaction kettle is controlled to be 5bar by nitrogen, and the reaction is stirred for 6 hours at the temperature of 200 ℃, so that 631.4g of 1-chloro-3, 3, 3-trifluoropropene is obtained.
(4) Preparation of 3,3, 3-trifluoro-2-chloropropene
126.3g of SbF were added to a 2L Monel autoclave IV5631.4g of 1-chloro-3, 3, 3-trifluoropropene are slowly added into the reaction kettle under the control of a gas flow meter; the temperature of the reaction kettle is raised to 200 ℃, the pressure of the reaction kettle is controlled to be 5bar, and 524.9g of 2-chloro-3, 3, 3-trifluoropropene is obtained after stirring and reacting for 10h under the condition.
(5) Preparation of 1,1,1, 2-tetrafluoro-2-chloropropane
55g of SbF were placed in a 2L Monel autoclave V3/SbCl5As catalyst, 524.9g of 2-chloro-3, 3, 3-trifluoropropene were added into the reactor through a mass flow meter, 250g of anhydrous HF was fed into the reactor through an HF feed pump, and N was used2Controlling the pressure of the reaction kettle to be 8bar, heating the reaction kettle to 120 ℃, and stirring and reacting for 8 hours under the condition to synthesize 558.4g of 2-chloro-1, 1,1, 2-tetrafluoropropane.
(6) Preparation of 2,3,3, 3-tetrafluoropropene
Adding 250g of 80% KOH solution and 558.4g of 2-chloro-1, 1,1, 2-tetrafluoropropane into a 2L hastelloy material high-pressure reaction kettle VI for HCl removal reaction. The reaction temperature is 150 ℃, the pressure is 10bar, and the stirring reaction is carried out for 10 hours, so that 354.8g of 2,3,3, 3-tetrafluoropropene is obtained.
The total conversion rate of the reaction was 36.4%, and the yield of 2,3,3, 3-tetrafluoropropene was 68.2% (as CH)2CHCl).
The above is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions or modifications made on the basis of the present invention to solve the same technical problems and achieve the same technical effects are all covered in the protection scope of the present invention.