CN1043571C - 1,1,1-trifluoroethane preparation by liquid-phase fluorization of unsym. vinylidene chloride - Google Patents

Abstract

The present invention discloses method for preparing 1, 1, 1-trifluoroethane from vinylidene chloride, which adopts two-stage continuous liquid phase anhyrous HF fluorination. In the first stage, catalysts of SnCl4, TiCl4, SO3, HSO3Cl or HSO3F are used, diluting agents which are 0.5 time to 3 times of the quantities of the catalysts are added, the molar ratio of HF to vinylidene chloride is from 1.0 to 1.5, the temperature is from 30 to 80 DEG C, and the pressure is from 0.1 to 1.5MPa; in the second stage, SbCl5, TaF5 or NbF5 and catalysts are used, diluting agents which are 1 time to 10 times of the quantities of the catalysts are added, the molar ratio of HF to HCFC141b in the products of the first stage is controlled from 2.0 to 2.5, the temperature is from 0 to 80 DEG C, and the pressure is from 0.1 to 0.5MPa. When the present invention is adopted, side reaction is little, the service life of the catalysts is long, and the reaction conversion rate and the selectivity are higher than 99%.

Description

Liquid fluoride vinylidene chloride system 1,1, the 1-Halothane

The present invention relates to by vinylidene chloride (CH ₂=CCl ₂) preparation 1,1, the method for 1-Halothane is particularly by vinylidene chloride and anhydrous HF liquid-phase fluorination preparation 1,1, the method for 1-Halothane.

1,1, the 1-Halothane, be called for short HFC143a, boiling point-48 ℃, AEL is 1000ppm, its ozone layer destroying potential value (ODP) is zero, it is as cooling agent, the volume refrigerating capacity is greater than HCFC22, and is lower than HCFC22 at the bottom of the exhaust temperature, therefore, the azeotrope that HFC143a or itself and other component form, nearly azeotropic mixture just are being used as the substitute of HCFC22 etc. and are carrying out extensive studies, and bear fruit.

Fluoridize preparation 1,1 by vinylidene chloride, the existing many patent documentation reports of 1-Halothane all are gaseous fluoridizing method wherein, as German publication Ger.offen1, and 246,703, be to contain Co ^H, Cr ^IHActivated alumina be catalyzer, 230 ℃ of temperature of reaction, HF and CH ₂CCl ₂Mol ratio be 4,10 seconds residence time, CH ₂CCl ₂Transformation efficiency be 79.9%, CH ₂CCl ₂Be converted into CH ₃CF ₃Selectivity be 90.7%; Ger.of-fen1,910,529 to contain Cr ^IH3.6% activated alumina is a catalyzer, 198 ℃ of temperature of reaction, HF and CH ₂CCl ₂Mol ratio is 3.5, and the residence time is 10 seconds, CH ₂CCl ₂Transformation efficiency be 99.2%, CH ₂CCl ₂Be converted into CH ₃CF ₃Selectivity be 99.6%; Japan's special permission 7617,544 is to contain Bi ^IHActivated alumina be catalyzer, 180 ℃ of temperature of reaction, 18 seconds residence time, HF and CH ₂CCl ₂Mol ratio be 3.2, CH ₂CCl ₂Transformation efficiency be 99.9%, CH ₂CCl ₂Be converted into CH ₃CF ₃Selectivity be 99.7%.

In the above-mentioned existing document, it is very long that gas phase fluorination prepares residence time of HFC143a, all above 10 seconds, thereby plant efficiency is low, and vinylidene chloride is a kind of alkene, is easy to polymerization and forms tarry oligopolymer and solid state polymkeric substance, particularly gas-phase reaction, temperature is higher, more quickened the polymerization coking speed of vinylidene chloride, this not only easily causes line clogging, and easily causes catalyst deactivation, shorten and urge the opinion agent life-span, make reaction be difficult to carry out continuously for a long time.

The inventor is at the existing in prior technology problem, react the mechanism that generates HFC143a according to vinylidene chloride and HF cleverly, adopt continuous liquid-phase fluorination process, add selection of catalysts, promote carrying out smoothly of fluoridation, and effectively suppressed the polymerization coking side reaction of vinylidene chloride, prolonged life of catalyst, increase plant efficiency, and obtained very high reaction conversion ratio and selectivity.

Prepare the addition reaction (1) that generally includes vinylidene chloride and HF among the HFC143a and the fluorine chlorine permutoid reaction [2,3] of adduct and the polymerization of vinylidene chloride by vinylidene chloride and anhydrous hydrogen fluoride reaction and pay reaction (4):

(1)

(HCFC141b)

(2)

(HCFC142b)

(3)

(HFC143a)

One of key of the present invention just is that selected processing condition and catalyzer will help main reaction (1), (2), and the carrying out smoothly of (3), and can effectively suppress to pay the generation of reaction (4).

The inventor discovers, temperature of reaction is an important factor.Temperature of reaction is high more, the tendency that reaction is paid in vinylidene chloride generation polymerization is big more, temperature of reaction reduces, then help improving main reaction (1), (2), (3) selectivity, so first important measures that the inventor makes for the generation of suppress paying reaction as far as possible are to adopt continuous liquid-phase catalysis fluorination method, and temperature of reaction is greatly reduced than gaseous fluoridizing method.And the inventor carries out reaction (1) major control by adopting two sections continuous liquid-phase catalysis flaorination process in first section reactor, reaction (2), and (3) major control is carried out in second section reaction.Two-stage reaction can adopt identical catalyst system, but control different reaction process conditions, also can adopt different catalyst systems and different reaction process conditions, thereby make reaction towards more helping main reaction (1), (2), (3) acceleration again can more effective inhibition and stop the generation of vinylidene chloride polymerization side reactions (4).

Accompanying drawing is seen in technical process of the present invention.

Material sodium chloro ethylene and anhydrous hydrogen fluoride enter first section liquid phase fluorination reactor (3) with volume pump from storage tank (1) and (2) with selected speed and carry out fluoridation, the HCFC141b mixture that generates alternately enters storage tank (5) or (6) from return line, the HCl that generates enters snubber (8) from condenser overhead, HCFC141b mixture and anhydrous hydrogen fluoride enter second section Liquid-phase reactor (7) with selected speed from (5) or (6) and (2), the HFC143a that generates enters snubber (8) from (7) condenser overhead, water wash column (9), soda-wash tower (10), gas holder (11), drying device (12) is pressed into crude product storage tank (14) with compressor (13) then.

First section liquid phase fluorination reactor selected the more weak SnCl of the ability of fluoridizing for use ₄, TiCl ₄, SO ₃, HSO ₃Cl or HSO ₃F is a catalyzer, and this catalyzer more can quicken the addition reaction of vinylidene chloride and HF, can suppress the vinylidene chloride polymerization again well and generate the tarry oligopolymer, thereby prolong catalyst life.

The temperature of reaction of first section reactor is high more, and the formation speed of HCFC141b is fast more, but the speed increase of vinylidene chloride polymerization generation tarry oligopolymer is faster, causes catalyst life to shorten significantly; Temperature of reaction reduces, and the HCFC141b formation speed slows down, and slows down manyly but vinylidene chloride generates the speed of tarry oligopolymer, so catalyst life can prolong greatly.Take all factors into consideration speed of response and catalyst life.Temperature of reaction of the present invention generally is controlled at 30 ℃-80 ℃.Especially the temperature of reaction of Shi Heing is 40-60 ℃.

The mol ratio of HF and vinylidene chloride can have influence on the transformation efficiency of vinylidene chloride and be converted into the selectivity of HCFC141b.HF and CH ₂=CCl ₂Mol ratio＞1.5, HCl content is more in the reactant, and the HCl that condenser overhead need be discharged is more; HF and CH ₂=CCl ₂Mol ratio＜1, unreacted CH in the resultant ₂=CCl ₂Content is more, influences the catalyst life of second section reactor.Suitable HF and CH ₂=CCl ₂Mol ratio be 1.0～1.5, especially suitable mol ratio is 1.2～1.3.

The pressure of first section reactor and the cooling temperature of condenser complement each other and interact, as to select the temperature of cooling water of condenser for use be 10～30 ℃, and then pressure-controlling is at 0.2～0.5MPa.

First section reactor domestic demand be added in be in the reaction inert material as thinner to keep catalyst concn moderate, prolong catalyst life.Suitable thinner is CFC112 (CCl ₂FCCl ₂F), CFC113 (CClF ₂CCl ₂F, HCFC122 (CHCl ₂CClF ₂) or HCFC121 (CHCl ₂CCl ₂F).Especially suitable diluent is CFC112 or CFC113.Suitable dilution dosage is 0.5～3 times of catalytic amount.

The suitable catalyzer of second section reactor is SbCl ₅, TaF ₆Or NbF ₅Or with first section identical catalyzer, SO ₃, SnCl ₄, HSO ₃F or HSO ₃Cl etc.SbCl ₆, TaF ₅Or NbF ₅The catalytic fluorination ability stronger, can select lower temperature of reaction and lower catalyst concn; SnCl ₄, HSO ₃F or HSO ₃The catalytic fluorination ability of Cl a little less than, then can select higher temperature of reaction and higher catalyst concn.

For keeping second section catalyst reactor concentration moderate, need be added in and be the inert material in the reaction to prolong catalyst life as thinner, also can HCFC141b as thinner.But operation easier is big, and suitable thinner is CFC113, CFC114 (CClF ₂CClF ₂) or CFC112.Suitable dilution dosage is 1～10 times of catalytic amount, and especially suitable concentration is 2-5 times of catalytic amount.

The temperature of second section reactor is high more, and then the formation speed of HFC113a is fast more, but catalyst life shortens; Temperature of reaction reduces, and the formation speed of HFC143a slows down, but catalyst life prolongs.Take all factors into consideration HFC143a formation speed and catalytic life, the optimum range of temperature of reaction is 0～80 ℃, and especially suitable temperature is 10-60 ℃.

HF that second section reaction adds is to be benchmark from the HCFC141b mixture in first section reactant, and both mol ratios can influence the transformation efficiency of HCFC141b and generate the selectivity of HFC143a.The mol ratio of HF and HCFC141b＜2, the selectivity that HCFC141b is converted into HFC143a reduces, and the content of HCFC142b increases in the crude product.The mol ratio of HF and HCFC141b＜2.5, HF accumulates in reactor, has reduced catalyst concn, the speed of response that slowed down, HF content increases in the HFC143a crude product of Yi Chuing simultaneously.Suitable HF and HCFC141b mole proportioning are 2.0～2.5, and especially Shi Yi mol ratio is 2.1～2.3.

It is one of key problem in technology of the present invention that the pressure of second section reaction is selected.Can synthesis under normal pressure, also can compressive reaction.Compressive reaction can be accelerated the formation speed of HFC143a.Under identical condensing temperature, pressure is high more, and the content of HFC143a is high more in the product of effusion reactor, and the content of HF is low more, thereby helps reaction.But hypertonia also increases the requirement of equipment and material-transporting system.Suitable reaction pressure is 0.1～1.5MPa, and especially suitable pressure is 0.5～1.0MPa.

By the inventive method, adopt two sections continuous liquid-phase fluorination process, the polymerization of vinylidene chloride is paid reaction and can effectively be suppressed, catalyst life obtains to prolong significantly, and the transformation efficiency of vinylidene chloride reaches more than 99%, HFC143a content also reaches more than 99% in the thick product of second stage reactor effusion after washing, alkali cleaning, presses second-stage reaction catalytic amount summation meter, and every gram catalyzer per hour can prepare the HFC143a0.3 gram.

Specify the present invention below for example.

Embodiment one

In technical process as shown in drawings, first section liquid phase fluorination reaction still (3) volume is 6 liters, 0.3 meter of condenser (4) area ², Stainless Steel Helices is equipped with at the middle part, and number of actual plates is 5.In reactor (3), add SO ₃400 grams add CFC thereafter ₁₁₂500 grams, feed water coolant at reacting kettle jacketing, add the HF80 gram with HF/ hour speed of 80 grams, thereafter feed hot water at reacting kettle jacketing, make temperature in the kettle rise to 50 ℃, add vinylidene chloride continuously with the speed of 300 grams per hour, with per hour 75 the gram speed add anhydrous hydrogen fluoride continuously, keep 25 ℃ of condenser cooling water temperature, question response pressure rises to gauge pressure 0.05MPa, begins from return line to storage tank (5) or (6) discharging.The control discharging speed is 370 grams per hour, and adjusting condenser (4) top venting speed is to keep the first stage reactor pressure-stabilisation at 0.05MPa.

The reactor volume of second section liquid phase fluorination reactor (7) is 4 liters, and the condenser condenses area is 0.2 meter ², the middle part is filled with Stainless Steel Helices, and number of actual plates is 5.In the reactor of (7), add SbCl ₅Catalyzer 350 grams, CFC ₁₁₃200 grams, the reacting kettle jacketing in (7) feeds cold water, keeps 10 ℃ of temperature in the kettle, and the condenser chuck feeds chilled brine, keeps (7) condenser overhead temperature of charge and is-10 ℃; Control HCFC141b mixture input speed is 370 Grams Per Hours, and the HF input speed is 135 Grams Per Hours, after question response device pressure liter reaches 1.0MPa, by condenser (7) top, emits reaction product.Enter gas holder (11) through washing (9), alkali cleaning (10),, use gas chromatographic analysis simultaneously in the preceding sampling of gas holder (11).Reaction result sees Table one.Table one

Reaction times accumulative total (hour)	Temperature of reaction		The alkali cleaning after product is formed M%			HFC143a output		CH 2=CCl 2
										One section	Two sections	HFC 143a	HCFC 142b	HCFC 141b	Grams Per Hour	Gram/gram hour	Transformation efficiency %	Selectivity %
	50 100 150 200 250 300	50 50 50 50 50 50	10 10 10 10 10 10	99.2 99.2 99.2 99.1 99.1 99.0	0.7 0.7 0.7 0.8 0.8 0.9	0.1 0.1 0.1 0.1 0.1 0.2	258 258 258 257 257 257	0.304 0.304 0.304 0.302 0.302 0.302	＞99.9 ＞99.9 ＞99.9 ＞99.9 ＞99.9 ＞99.9										99.3 99.3 99.3 99.2 99.2 99.2

Embodiment two, three, four, five, six

Operation steps is with embodiment two.Change catalyst type, quantity is constant.Embodiment one is SnCl ₄, embodiment three is TiCl ₄, embodiment four is a chlorsulfonic acid, embodiment five is a fluosulfonic acid, the results are shown in Table two.Table two

Sequence number	Catalyst type	Temperature of reaction		The alkali cleaning after product is formed M%			HFC143a output		CH 2=CCl 2
											One section	Two sections	HFC 143a	HCFC 142a	HCFC 141b	Grams Per Hour	Gram/gram hour	Transformation efficiency %	Selectivity %
		2 3 4 5	SnCl 4TiCl 4HSO 3Cl HSO 3F	50 50 50 50	60 60 60 60	99.2 99.0 99.2 99 2	0 7 0 9 0 7 0.7	0.1 0.1 0.1 0 1	258 257 258 258	0.304 0.302 0.304 0.304										＞99.9 ＞99.9 ＞99.9 ＞99.9	99.2 99.0 99.2 99.2

Claims (2)

1, a kind of by vinylidene chloride and anhydrous HF prepared in reaction 1,1, the method for 1-Halothane is characterized in that adopting two sections continuous liquid-phase catalysis fluorination methodes, adds SnCl in first section reactor ₄, TiCl ₄, SO ₃, HSO ₃Cl or HSO ₃The F catalyzer adds catalytic amount 0.5-3 CCl doubly ₂FCCl ₂F, CClF ₂CCl ₂F, CHCl ₂CClF ₂Or CHCl ₂CCl ₂The F thinner, control HF and vinylidene chloride mol ratio are 1.0-1.5, and temperature of reaction is controlled at 30-80 ℃, and the temperature of cooling water of condenser is controlled at 10-30 ℃, and the pressure of reactor is 0.2-0.5MPa; Add SbCl in second section reactor ₅, TaF ₅, NbF ₅, SO ₃, SnCl ₄, HSO ₃F or HSO ₃The Cl catalyzer, the 1-10 CClF doubly of adding catalytic amount ₂CCl ₂F, CClF ₂CClF ₂Or CCl ₂FCCl ₂The F thinner, control HF with from first section product C H ₃CCl ₂The mol ratio of H is at 2.0-2.5, and temperature of reaction is 0-80 ℃, reaction pressure 0.1-1.5MPa.

2,, it is characterized in that first section reaction adds the 0.5-3 CCl doubly of catalytic amount by the said method of claim 1 ₂FCCl ₂F or CClF ₂CCl ₂The F thinner, the mol ratio of HF and vinylidene chloride is 40-60 ℃ for the 1.2-1.3 temperature of reaction; Second section reactor adds catalytic amount 2-5 CClF doubly ₂CCl ₂F or CClF ₂CCl ₂The F thinner, HF with from CH in first section the product ₃CCl ₂The H mol ratio is controlled at 2.1-2.3, and temperature of reaction is 10-60 ℃, reaction pressure 0.5-1.0MPa.