CA2016691A1 - Gas phase catalytic disproportionation of 1-chloro-1,1-difluoroethane - Google Patents
Gas phase catalytic disproportionation of 1-chloro-1,1-difluoroethaneInfo
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- CA2016691A1 CA2016691A1 CA 2016691 CA2016691A CA2016691A1 CA 2016691 A1 CA2016691 A1 CA 2016691A1 CA 2016691 CA2016691 CA 2016691 CA 2016691 A CA2016691 A CA 2016691A CA 2016691 A1 CA2016691 A1 CA 2016691A1
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- CA
- Canada
- Prior art keywords
- catalyst
- chloro
- process according
- difluoroethane
- nicl2
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/25—Preparation of halogenated hydrocarbons by splitting-off hydrogen halides from halogenated hydrocarbons
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
GAS PHASE CATALYTIC DISPROPORTIONATION
OF 1-CHLORO-1,1-DIFLUOROETHANE
Abstract of the Disclosure 1-Chloro-1-fluoroethylene/vinylidene fluoride mixtures are prepared from the gas phase disproportionation of 1-chloro-1,1-difluoroethane in the presence of a NiF2-containing catalyst.
OF 1-CHLORO-1,1-DIFLUOROETHANE
Abstract of the Disclosure 1-Chloro-1-fluoroethylene/vinylidene fluoride mixtures are prepared from the gas phase disproportionation of 1-chloro-1,1-difluoroethane in the presence of a NiF2-containing catalyst.
Description
2~6~
,... .
GAS PHASE CATALYTIC DISPROPORTIONATION
OF 1--CHI.ORO~ DIFLUOROETI~F~NE ::
Field of the Invention The invention relates to the gas phase production 5of vinylidene fluoride and l-chloro-1-fluoroethylene, in particular the production of vinylidene fluoride and 1-chloro-l-fluoroethylene by a gas phase catalytic dispropor-tionation process. ;
Backqround of the Invention 10The gas phase catalytic dehydrohalogenation of l-chloro-l,1-difluoroethane has been reporked to proceed with elimination of HCl, with very little dehydrofluorination.
Walker, et al., J. Org. Chem. 30, 3284-3285 (1965). The process was carried out between 300-400C utilizing silver 15metal, Nio, Fe2O3 or Zno. When Al203 or sio2 was used as the catalyst, the main product was 1-chloro-l-fluoroeth-ylene, which resulted from the elimination of HF. The minor product, vinylidene fluoride, resulted from the elimination of HCl. A mixture of silica and alumina 20catalyst (12.4 wt.% Al203 ancl 87.3 wt.~ Sio2) resulted in hoth dehydrochlorination and dehydrofluorination, with the product distribution depending upon the temperature.
Analysis of the oxide catalysts indicates that 5-10% of the catalyst reacted with HF or HCl. Such catalyst consumption `
25reduces both catalyst lifetime and activity.
MGller, et~al., Chem~ Ing. Tech. 56 (8), 626-628 (1984) discloses dehydrochlorination of l-chloro-l,l-difluoroethane in the presence of anhydrous NiCl2. The ~
':.
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g 05-2 58 ; - 1 -~: ` '`'"l''.' :
.
6~
process was very selective at 400C. A small percentage of oxygen (1.5%), based upon the volume of l-chloro-l,l-difluoroethane fead, was utilized as a co-reactant. Under these conditions, conversion of 1-chloro~1,1-difluoroethane was 80%, with 100% selectivity for vinylidene fluoride. No 1-chloro-1-fluoroethylene was formed.
U.S. Patent 2,894,043 discloses the dehydrofluori-nation of l-chloro-1,1-difluoroethane to 1-chloro~1-fluoro-ethylene at a temperature of 46S-535C, i,n a reactor packed with nickel metal helices.
Summarv of the Invention A process for the preparation of mixtures compris-ing l-chloro-1-fluoroethylene and vinylidene fluoride is provided. l-Chloro-l,l-difluoroethane is contacted in the gaseous phase with a NiF2-containing catalyst at a reaction temperature of from about 200C to about 700C. Both vinylidene fluoride and 1-chloro-}-fluoroethylene are thus prepared in a single step. They may be easily separated by standard distillation methods owing to their large dif-~erence in boiling points. Vinylidene fluoride bails at -86C; 1-chloro-1-fluoroethylene boils at -24C.
The process of the invention is particularly useful for preparing mixtures wherein vinylidene fluoride and 1-chloro-l-fluoroethylene comprise in combination at least about 50 mol%, preferably at least about 60 mol%, of the product mixture formed from the disproportionation of 1-chloro-1,1-difluoroethane.
Detailed Description~of the Invention Both vinylidene fluoride and 1-chloro-1-fluoroeth-ylene are monomers which may be used for the preparation of useful polymers. Vinylidene fluoride is used in the production of polyvinylidene fluoride. 1-Chloro-1-fluoro-ethylene may be utilized in the production of elastomeric fluoroolefins. See U.S. Patents 2,777,833 and 2,894,043;
The present invention provides a convenient process for -,,.: ' .. ' , -:
. . .
2~6~
producing both vinylidene fluoride and l-chloro-l-fluoro~
ethylene in a single step.
According to the present invention, a NiF2-contain-ing catalyst is advantageously utilized for th2 gas phase production of vinylidene fluoride and 1-chloro-1-fluoro-ethylene from l-chloro~ difluoroethclne. By "NiF2-containing catalyst" is meant pure NiF2, or NiF2 contained on a support such as AlF3 and the like. Also included in the definition of "NiF2-containing catalyst" is fluorided NiCl2, which may likewise be optionally contained on a suitable support, e.g. Al2O3. By "fluorided NiCl2" is meant NiCl2, a substantial portion thereof which has been converted to NiF2 by the catalyst activation sequence as hereinafter described. Thus, while Muller, et al., Chem.
Ing. Tech. 56 (8), 626-628 (198~) disclose unactivated NiCl2 as the catalyst for the dehydrochlorination of 1-chloro-l,l-difluoroethane, the present invention utilizes NiF2, or NiCl2 which has been appropriately "fluorided".
At temperatures below about 400C the major pro-ducts obtained are generally 1,1,1-trifluoroethane and 1-chloro-l-fluoroethylene, with vinylidene fluoride present, but as a minor product. At temperatures above about 400C, vinylidene fluoride is generally formed at the expense of l,l,l-trifluoroethane, and the principal products are vinylidene fluoride and l-chlorv-l-fluoroethylene. A small percentage of vinylidene chloride is also observed, presum-ably from the dehydrofluorination of l,l-dichloro-l-fluoro-ethane.
Without wishin~ to be bound by any theory, it is believed that this product distribution results from a disproportionation process. According to the probable disproportionation mechanism, two moles of l-chloro-l,l-difluoroethane disproportionate to form one mole each of l,1,1-trifluoroethane and 1,1-dichloro-1-fluoroethane.
1,1,1-Trifluoroethane dehydrofluorinates to form HF and . :.
,~ , 905 258 -~-~. ,;
--- 21~ ~6~L
vinylidene fluoride. l,l-Dichloro-l-fluoroethane dehydro-chlorinates to form HCl and l-chloro-l-fluoroethylene.
The reaction temperature is from about 200C to about 700C, preferably from about 400C to about 600C, most preferably from about 500C to about 600C. General-ly, higher temperatures favor the production of vinylidene fluoride at the expense of l,l,l-trifluoroethane. Thus, temperatures above about 400C, most preferably above about 600C, are preferred to maximize vinylidene fluoride production over 1,1,1-trifluoroethane production.
A small amount of oxygen may be optionally combined with the l-chloro-1,1-difluoroethane feed as a co-reactant.
Thus, oxygen may be c~mbined with the l-chloro-l,l-difluo-roethane in an amount of from about 2% to about 21% by volume, based upon the volume of l-chloro~ difluoro-ethane passed over the catalyst. Preferably, the amount of oxygen is from about 4% to about 8%. The oxygen may be supplied in the form of substantially pure oxygen or may be supplied in the form of a gas containing oxygen, such as air or a synthetic mixture o~ molecular oxygen with mostly inert gases. Where a mixture of gases is employed, the volume of gas supplied should be increased proportionately to take into account the oxygen content of the gas.
The contact time of the reactants with the catalyst may vary considerably. Preferably, the contact time is from about 10 seconds to about 100 seconds, most preferably from about 40 seconds to about 70 seconds.
Air activation of the catalyst before introducing the reactant feed is advantageously conducted to boost catalyst performance. The catalyst may be treated in this manner by flowing air over the catalyst at a temperature from about 100C to about 1000C, at an air flow rate of from about 1 to about 10 cm3/min. per cm3 of catalyst, for at lsast about 24 hours. Preferably, the temperature of the air is from about 200C to about 700C.
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Where thP catalyst comprises fluorided NiCl2, the starting catalyst NiCl2 bed, after air activation substan-tially as above, is thereafter activated with hydrogen fluoride by flowing hydrogen fluoride over the catalyst bed at elevated temperature in an amount of from about 20~ to about 60% by volume in excess of the theoretical amount of hydrogen fluoride required to convert the NiCl2 in the bed to NiF2. sy way of example, if the theoretical amount of hydrogen fluoride required to completely convert the NiCl2 to NiF2 is l mole, then from about 1.2 to about 1.6 moles of hydrogen fluoride are advantageous passed through the NiCl2 bed.
The process of the present invention is illustrated in the following non-limiting examples.
Alumina (200 g, Harshaw 3952) was added portionwise at 45C into a stirred solution of aqueous hydrogen fluor-ide (500 ml of 50% HF) over the course of 6 hours.
AlF3-3H2O was precipitated when the solution was le~t standing at room temperature overnight. To this mixture was added 29.94 g NiCl2 portionwise at room temperature. A
light green solid was precipitated out from the mixture.
The precipitated NiF2/AlF3 was filtered, air dried and heated gradually at the following temperatures: (1) 100C
for 2 hours, ~2) 150C for 2 hours, and (3) 175C for 18 hours. The catalyst was then ground and sieved. Of the resulting 60-100 mesh particles, 22.45 g were loaded into a Hastelloy C tubular reactor. The catalyst was activated at 650C wlth continuously flowing air fed into the reactor over the catalyst bed at a rate of 20 cm3/min. for 18 hours. The air~activated catalyst was then activated with hydrogen fluoride by flowing 0.08 g/min. of hydrogen fluoride and 20 cm3/min. of nitrogen for 6 hours at 550C.
A total of 29 g of hydrogen fluoride were flowed over the catalyst. A gas feed consisting of 94.3% 1-chloro-l,l-difluoroethane and 5.7% 2 by volume was introduced into ' '`
, :, .:
.. ... . . . . .. ~ , , . ~ ~ . . . . . .
2~6g~L , the reactor at 450c. The reaction proclucts were removed at the bottom of the reactor and then passed up to a scrubbing tower, countercurrent to a liquid alkaline stream of 1-5 N aqueous KOH in order to remove hydrogen fluoride.
Other aqueous hydroxides such as NaOH or Ca(OH) 2 may be substituted for KOH. The organic product was then passed through a drying tower packed with a drying agent (anhy-drous calcium sulfate). The conversion of l-chloro-l,l-difluoroethane was periodically check by passing product automatically ~o a gas chromatograph equipped with an electronic integrator. The mass balance was evaluated by passing the outlet gas from the gas chromatograph through a wet test meter. Gas chromatograph analysis indicated a 92.7% conversion of l-chloro-l,l-difluoroethane. The 5 product distribution is set forth in Table 1.
The procedure of Example 1 was repeated except that the reaction temperature was increased to 490C, and the ~eed consisted of 77.6% l-chloro-1,1-difluoroethane and 22.4% air, by volume. The results are tabulated in Table 1. , :.
The procedure of Example 2 was repeated except that the reaction temperature was increased to 525~C. The results are tabulated in Table 1.
NiF2-4H2o (32 g) was loaded into the same reactor utilized in Example 1 and heated to 600C. The catalyst was treated with flowing air at 20 cm3/min. for 18 hours.
Thereafter l-chloro-l,l-difluoroethane ~18 cm3/min.) together with air (5.2 cm3/min.) were continuously fed over the catalyst bed at 400C, 450C and 575C. The results appear in Table 1.
NiCl2-6H2O t32 g, 0.25 mole) was loaded into the same reactor used in Example 1. The catalyst was heated to . ~ . .
~20~669~
200C using 20 cm3/min. air for 21 hours. The air-acti-vated catalyst was thereafter treated by flowing hydrogen fluoride (0.03 g/min.) up to a total of ll g, in combina-tion with 20 cm3/min. nitrogen at 400C. Upon completion of the catalyst activation, a mixture o~E 92.4% l-chloro-l,l-difluoroethane and 7.6% oxygen by volume was fed to the reactor at temperatures of 400D C and 450C. The results are tabulated in Table 1.
NiCl2-6H2O (30 g) were dissolved in 200 ml of hot water with continuous stirring. Gamma-alumina (lO0 g) was added to ths hot green solution. The mixture was left overnight at room temperature. The mixture was thereafter filtered and air dried. The air dried catalyst (50 g) was loaded onto the same reactor utilized in Example 1. The catalyst was activated at 650C with air flowing at a rate of 20 cm3/min. for 60 hours. The catalyst was thereafter treated with hydrogen fluoride (0.~ g/min.) for 6 hours, resulting in a total 72 g of hydrogen fluoride being passed over the catalyst bed. A mixture of 91.9~ 1-chloro-1,1-difluoroethane and 8.1% oxygen by volume was introduced into the reactor. The results are set forth in Table 1.
905-25~ -7-L61~9~L
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ooo 000 ooO~
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The present inven~ion may be embodied in other specific forms without departing from the spirit or essen-tial attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the fore- ::
going specification, as indicating the scope of the inven-tion.
905-258 ~9~ :
,... .
GAS PHASE CATALYTIC DISPROPORTIONATION
OF 1--CHI.ORO~ DIFLUOROETI~F~NE ::
Field of the Invention The invention relates to the gas phase production 5of vinylidene fluoride and l-chloro-1-fluoroethylene, in particular the production of vinylidene fluoride and 1-chloro-l-fluoroethylene by a gas phase catalytic dispropor-tionation process. ;
Backqround of the Invention 10The gas phase catalytic dehydrohalogenation of l-chloro-l,1-difluoroethane has been reporked to proceed with elimination of HCl, with very little dehydrofluorination.
Walker, et al., J. Org. Chem. 30, 3284-3285 (1965). The process was carried out between 300-400C utilizing silver 15metal, Nio, Fe2O3 or Zno. When Al203 or sio2 was used as the catalyst, the main product was 1-chloro-l-fluoroeth-ylene, which resulted from the elimination of HF. The minor product, vinylidene fluoride, resulted from the elimination of HCl. A mixture of silica and alumina 20catalyst (12.4 wt.% Al203 ancl 87.3 wt.~ Sio2) resulted in hoth dehydrochlorination and dehydrofluorination, with the product distribution depending upon the temperature.
Analysis of the oxide catalysts indicates that 5-10% of the catalyst reacted with HF or HCl. Such catalyst consumption `
25reduces both catalyst lifetime and activity.
MGller, et~al., Chem~ Ing. Tech. 56 (8), 626-628 (1984) discloses dehydrochlorination of l-chloro-l,l-difluoroethane in the presence of anhydrous NiCl2. The ~
':.
' ,~ .
g 05-2 58 ; - 1 -~: ` '`'"l''.' :
.
6~
process was very selective at 400C. A small percentage of oxygen (1.5%), based upon the volume of l-chloro-l,l-difluoroethane fead, was utilized as a co-reactant. Under these conditions, conversion of 1-chloro~1,1-difluoroethane was 80%, with 100% selectivity for vinylidene fluoride. No 1-chloro-1-fluoroethylene was formed.
U.S. Patent 2,894,043 discloses the dehydrofluori-nation of l-chloro-1,1-difluoroethane to 1-chloro~1-fluoro-ethylene at a temperature of 46S-535C, i,n a reactor packed with nickel metal helices.
Summarv of the Invention A process for the preparation of mixtures compris-ing l-chloro-1-fluoroethylene and vinylidene fluoride is provided. l-Chloro-l,l-difluoroethane is contacted in the gaseous phase with a NiF2-containing catalyst at a reaction temperature of from about 200C to about 700C. Both vinylidene fluoride and 1-chloro-}-fluoroethylene are thus prepared in a single step. They may be easily separated by standard distillation methods owing to their large dif-~erence in boiling points. Vinylidene fluoride bails at -86C; 1-chloro-1-fluoroethylene boils at -24C.
The process of the invention is particularly useful for preparing mixtures wherein vinylidene fluoride and 1-chloro-l-fluoroethylene comprise in combination at least about 50 mol%, preferably at least about 60 mol%, of the product mixture formed from the disproportionation of 1-chloro-1,1-difluoroethane.
Detailed Description~of the Invention Both vinylidene fluoride and 1-chloro-1-fluoroeth-ylene are monomers which may be used for the preparation of useful polymers. Vinylidene fluoride is used in the production of polyvinylidene fluoride. 1-Chloro-1-fluoro-ethylene may be utilized in the production of elastomeric fluoroolefins. See U.S. Patents 2,777,833 and 2,894,043;
The present invention provides a convenient process for -,,.: ' .. ' , -:
. . .
2~6~
producing both vinylidene fluoride and l-chloro-l-fluoro~
ethylene in a single step.
According to the present invention, a NiF2-contain-ing catalyst is advantageously utilized for th2 gas phase production of vinylidene fluoride and 1-chloro-1-fluoro-ethylene from l-chloro~ difluoroethclne. By "NiF2-containing catalyst" is meant pure NiF2, or NiF2 contained on a support such as AlF3 and the like. Also included in the definition of "NiF2-containing catalyst" is fluorided NiCl2, which may likewise be optionally contained on a suitable support, e.g. Al2O3. By "fluorided NiCl2" is meant NiCl2, a substantial portion thereof which has been converted to NiF2 by the catalyst activation sequence as hereinafter described. Thus, while Muller, et al., Chem.
Ing. Tech. 56 (8), 626-628 (198~) disclose unactivated NiCl2 as the catalyst for the dehydrochlorination of 1-chloro-l,l-difluoroethane, the present invention utilizes NiF2, or NiCl2 which has been appropriately "fluorided".
At temperatures below about 400C the major pro-ducts obtained are generally 1,1,1-trifluoroethane and 1-chloro-l-fluoroethylene, with vinylidene fluoride present, but as a minor product. At temperatures above about 400C, vinylidene fluoride is generally formed at the expense of l,l,l-trifluoroethane, and the principal products are vinylidene fluoride and l-chlorv-l-fluoroethylene. A small percentage of vinylidene chloride is also observed, presum-ably from the dehydrofluorination of l,l-dichloro-l-fluoro-ethane.
Without wishin~ to be bound by any theory, it is believed that this product distribution results from a disproportionation process. According to the probable disproportionation mechanism, two moles of l-chloro-l,l-difluoroethane disproportionate to form one mole each of l,1,1-trifluoroethane and 1,1-dichloro-1-fluoroethane.
1,1,1-Trifluoroethane dehydrofluorinates to form HF and . :.
,~ , 905 258 -~-~. ,;
--- 21~ ~6~L
vinylidene fluoride. l,l-Dichloro-l-fluoroethane dehydro-chlorinates to form HCl and l-chloro-l-fluoroethylene.
The reaction temperature is from about 200C to about 700C, preferably from about 400C to about 600C, most preferably from about 500C to about 600C. General-ly, higher temperatures favor the production of vinylidene fluoride at the expense of l,l,l-trifluoroethane. Thus, temperatures above about 400C, most preferably above about 600C, are preferred to maximize vinylidene fluoride production over 1,1,1-trifluoroethane production.
A small amount of oxygen may be optionally combined with the l-chloro-1,1-difluoroethane feed as a co-reactant.
Thus, oxygen may be c~mbined with the l-chloro-l,l-difluo-roethane in an amount of from about 2% to about 21% by volume, based upon the volume of l-chloro~ difluoro-ethane passed over the catalyst. Preferably, the amount of oxygen is from about 4% to about 8%. The oxygen may be supplied in the form of substantially pure oxygen or may be supplied in the form of a gas containing oxygen, such as air or a synthetic mixture o~ molecular oxygen with mostly inert gases. Where a mixture of gases is employed, the volume of gas supplied should be increased proportionately to take into account the oxygen content of the gas.
The contact time of the reactants with the catalyst may vary considerably. Preferably, the contact time is from about 10 seconds to about 100 seconds, most preferably from about 40 seconds to about 70 seconds.
Air activation of the catalyst before introducing the reactant feed is advantageously conducted to boost catalyst performance. The catalyst may be treated in this manner by flowing air over the catalyst at a temperature from about 100C to about 1000C, at an air flow rate of from about 1 to about 10 cm3/min. per cm3 of catalyst, for at lsast about 24 hours. Preferably, the temperature of the air is from about 200C to about 700C.
gO5-258 -4-. . .
o~
Where thP catalyst comprises fluorided NiCl2, the starting catalyst NiCl2 bed, after air activation substan-tially as above, is thereafter activated with hydrogen fluoride by flowing hydrogen fluoride over the catalyst bed at elevated temperature in an amount of from about 20~ to about 60% by volume in excess of the theoretical amount of hydrogen fluoride required to convert the NiCl2 in the bed to NiF2. sy way of example, if the theoretical amount of hydrogen fluoride required to completely convert the NiCl2 to NiF2 is l mole, then from about 1.2 to about 1.6 moles of hydrogen fluoride are advantageous passed through the NiCl2 bed.
The process of the present invention is illustrated in the following non-limiting examples.
Alumina (200 g, Harshaw 3952) was added portionwise at 45C into a stirred solution of aqueous hydrogen fluor-ide (500 ml of 50% HF) over the course of 6 hours.
AlF3-3H2O was precipitated when the solution was le~t standing at room temperature overnight. To this mixture was added 29.94 g NiCl2 portionwise at room temperature. A
light green solid was precipitated out from the mixture.
The precipitated NiF2/AlF3 was filtered, air dried and heated gradually at the following temperatures: (1) 100C
for 2 hours, ~2) 150C for 2 hours, and (3) 175C for 18 hours. The catalyst was then ground and sieved. Of the resulting 60-100 mesh particles, 22.45 g were loaded into a Hastelloy C tubular reactor. The catalyst was activated at 650C wlth continuously flowing air fed into the reactor over the catalyst bed at a rate of 20 cm3/min. for 18 hours. The air~activated catalyst was then activated with hydrogen fluoride by flowing 0.08 g/min. of hydrogen fluoride and 20 cm3/min. of nitrogen for 6 hours at 550C.
A total of 29 g of hydrogen fluoride were flowed over the catalyst. A gas feed consisting of 94.3% 1-chloro-l,l-difluoroethane and 5.7% 2 by volume was introduced into ' '`
, :, .:
.. ... . . . . .. ~ , , . ~ ~ . . . . . .
2~6g~L , the reactor at 450c. The reaction proclucts were removed at the bottom of the reactor and then passed up to a scrubbing tower, countercurrent to a liquid alkaline stream of 1-5 N aqueous KOH in order to remove hydrogen fluoride.
Other aqueous hydroxides such as NaOH or Ca(OH) 2 may be substituted for KOH. The organic product was then passed through a drying tower packed with a drying agent (anhy-drous calcium sulfate). The conversion of l-chloro-l,l-difluoroethane was periodically check by passing product automatically ~o a gas chromatograph equipped with an electronic integrator. The mass balance was evaluated by passing the outlet gas from the gas chromatograph through a wet test meter. Gas chromatograph analysis indicated a 92.7% conversion of l-chloro-l,l-difluoroethane. The 5 product distribution is set forth in Table 1.
The procedure of Example 1 was repeated except that the reaction temperature was increased to 490C, and the ~eed consisted of 77.6% l-chloro-1,1-difluoroethane and 22.4% air, by volume. The results are tabulated in Table 1. , :.
The procedure of Example 2 was repeated except that the reaction temperature was increased to 525~C. The results are tabulated in Table 1.
NiF2-4H2o (32 g) was loaded into the same reactor utilized in Example 1 and heated to 600C. The catalyst was treated with flowing air at 20 cm3/min. for 18 hours.
Thereafter l-chloro-l,l-difluoroethane ~18 cm3/min.) together with air (5.2 cm3/min.) were continuously fed over the catalyst bed at 400C, 450C and 575C. The results appear in Table 1.
NiCl2-6H2O t32 g, 0.25 mole) was loaded into the same reactor used in Example 1. The catalyst was heated to . ~ . .
~20~669~
200C using 20 cm3/min. air for 21 hours. The air-acti-vated catalyst was thereafter treated by flowing hydrogen fluoride (0.03 g/min.) up to a total of ll g, in combina-tion with 20 cm3/min. nitrogen at 400C. Upon completion of the catalyst activation, a mixture o~E 92.4% l-chloro-l,l-difluoroethane and 7.6% oxygen by volume was fed to the reactor at temperatures of 400D C and 450C. The results are tabulated in Table 1.
NiCl2-6H2O (30 g) were dissolved in 200 ml of hot water with continuous stirring. Gamma-alumina (lO0 g) was added to ths hot green solution. The mixture was left overnight at room temperature. The mixture was thereafter filtered and air dried. The air dried catalyst (50 g) was loaded onto the same reactor utilized in Example 1. The catalyst was activated at 650C with air flowing at a rate of 20 cm3/min. for 60 hours. The catalyst was thereafter treated with hydrogen fluoride (0.~ g/min.) for 6 hours, resulting in a total 72 g of hydrogen fluoride being passed over the catalyst bed. A mixture of 91.9~ 1-chloro-1,1-difluoroethane and 8.1% oxygen by volume was introduced into the reactor. The results are set forth in Table 1.
905-25~ -7-L61~9~L
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. o I ~';
z !
~ ~ ~ rl~ .~_ _ _ ;~ . .
Z
. .
~ : ', ' ~ ' 2~ 6~ ~
The present inven~ion may be embodied in other specific forms without departing from the spirit or essen-tial attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the fore- ::
going specification, as indicating the scope of the inven-tion.
905-258 ~9~ :
Claims (17)
- THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
l. A process for the preparation of mixtures comprising 1-chloro-1-fluoroethylene and vinylidene fluor-ide comprising contacting 1-chloro-1,1-difluoroethane in the gaseous phase with a NiF2-containing catalyst at a reaction temperature of from about 200°C to about 700°C. - 2. A process according to claim 1 wherein the reaction temperature is from about 400°C to about 600°C.
- 3. A process according to claim 2 wherein the reaction temperature is from about 500°C to about 600°C.
- 4. A process according to claim 1 wherein the catalyst is NiF2.
- 5. A process according to claim 4 wherein the catalyst is NiF2 supported on AlF3.
- 6. A process according to claim 1 wherein the catalyst is fluorided NiCl2.
- 7. A process according to claim 6 wherein the catalyst is fluorided NiCl2 supported on Al203.
- 8. A process according to claim 1 wherein the 1-chloro-1,1-difluoroethane is in contact with the catalyst for from about 70 seconds to about 100 seconds.
- 9. A process according to claim 8 wherein the 1-chloro-1,1-difluoroethane is in contact with the catalyst for from about 40 seconds to about 70 seconds.
- 10. A process according to claim 1 wherein the l-chloro-1,1-difluoroethane is combined with from about 2% to about 21% oxygen by volume, based upon the volume of said 1-chloro 1,1-difluoroethane contacted with the catalyst.
- 11. A process according to claim 10 wherein the 1-chloro-1,1-difluoroethane is combined with from about 4%
to about 8% oxygen by volume, based upon the volume of said 1-chloro-1,1-difluoroethane contacted with the catalyst. - 12. A process according to claim 1 wherein the catalyst has been treated prior to contacting the 1-chloro-1,1-difluoroethane by flowing air over the catalyst at a temperature of from about 100°C to about 1000°C, at an air flow rate of from about 1 cm3/min. to about 10 cm3/min., per cm3 of catalyst, for at least about 24 hours.
- 13. A process according to claim 12 wherein the air temperature is from about 200°C to about 700°C.
- 14. A process according to claim 12 wherein the catalyst comprises fluorided NiCl2, which catalyst is prepared by flowing air over a catalyst bed comprising NiCl2, and thereafter flowing hydrogen fluoride over the catalyst bed in an amount of from about 20% to about 60% by volume in excess of the theoretical amount of hydrogen fluoride required to convert the NiCl2 in the bed to NiF2.
- 15. A process according to claim 14 wherein the catalyst comprises fluorided NiCl2 on Al2O3 .
- 16. A process according to claim 1 wherein at least about 50 mol% of the mixture comprises the combina-tion of 1-chloro-1-fluoroethylene and vinylidene fluoride.
- 17. A process according to claim 16 wherein at least about 60 mol% of the mixture comprises the combina-tion of 1-chloro-1-fluoroethylene and vinylidene fluoride.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/373,123 US4992727A (en) | 1988-06-29 | 1989-06-28 | Integrated circuits |
| US373,123 | 1989-06-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2016691A1 true CA2016691A1 (en) | 1990-12-28 |
Family
ID=23471064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2016691 Abandoned CA2016691A1 (en) | 1989-06-28 | 1990-05-14 | Gas phase catalytic disproportionation of 1-chloro-1,1-difluoroethane |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2016691A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106588563A (en) * | 2016-12-28 | 2017-04-26 | 浙江工业大学 | Preparation method of 1,1-difluoroethylene |
-
1990
- 1990-05-14 CA CA 2016691 patent/CA2016691A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106588563A (en) * | 2016-12-28 | 2017-04-26 | 浙江工业大学 | Preparation method of 1,1-difluoroethylene |
| CN106588563B (en) * | 2016-12-28 | 2019-02-05 | 浙江工业大学 | A kind of preparation method of 1,1- difluoroethylene |
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