CA1298315C - Process for the preparation of fluorobenzaldehydes - Google Patents
Process for the preparation of fluorobenzaldehydesInfo
- Publication number
- CA1298315C CA1298315C CA000550628A CA550628A CA1298315C CA 1298315 C CA1298315 C CA 1298315C CA 000550628 A CA000550628 A CA 000550628A CA 550628 A CA550628 A CA 550628A CA 1298315 C CA1298315 C CA 1298315C
- Authority
- CA
- Canada
- Prior art keywords
- fluoride
- dipolar aprotic
- aprotic medium
- range
- chlorine
- 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.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C47/00—Compounds having —CHO groups
- C07C47/52—Compounds having —CHO groups bound to carbon atoms of six—membered aromatic rings
- C07C47/55—Compounds having —CHO groups bound to carbon atoms of six—membered aromatic rings containing halogen
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
- C07C45/61—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups
- C07C45/63—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by reactions not involving the formation of >C = O groups by introduction of halogen; by substitution of halogen atoms by other halogen atoms
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Abstract A process for the production of fluorobenzaldehydes which comprises reacting a chlorobenzaldehyde with an alkali fluoride in a dipolar aprotic medium.
Description
~OECHST AKTIENGESELLSCHAFT HOE 86/F 270 Dr. Klr/St Description Process for the preparation of fluorobenzaldehydes Fluorobenzaldehydes are compounds which are derived from benzaldehyde C6H5CHO by replacing one or more hydrogen atoms of the C6Hs group by fluorine atoms and, optionalLy, also by other substituents in addition. They are mainly intermediate products, for example, in the preparation of pharmaceutical products and crop protection agents.
Various processes are known for the preparation of fluoro-benzaldehydes. Thus, for example, German Auslegeschrift 2,039,426 (Example 7) describes the preparation of 2,4-and 3,4-difluorobenzaldehyde in 70 and 76% yield respec-tively; the reaction proceeds according to the following formulation:
o CH3 CHBr2 C ~H
~F 2 Br2, light ~F Hydrolysj5~CaC03~ H20) ~F
F F F
According to EP-A-0,117,100 (Preparation 3, page 16), 2,4-difluorobenzaldehyde is obtained in good yield also by the follo~ing path:
o Br Li C ~ H
~ 1 1) Dimethylformamide ~ F ~ F 2) HydrolYsis ~ F
~-Butyllithium ~ ~H20~NH4Cl) F F F
The starting products for these reactions can be obtained, for example, by a single or multiple Balz-Schiemann reac-tion. The term "Balz-Schiemann reaction" is understood to mean the thermal decomposition of aromatic diazonium ~L
lZ~ lS
tetrafluoroborates to the correspond;ng aromatic fluorine compounds. The formulation, for example, for the prepara-tion of 2,4-difluorotoluene, may be reproduced as follows:
S ~
NH2 1) Diazotiza~ion(HNo2lH~l BF~N--N
CH3 ~NH2 2) }D3F4 N-N(~)BF~) F
Heating Z~
~ C~3-~ ~-P ~ 2 N2 ~ 2 BF3 Starting from common starting products, these processes consequently involve multi-stage syntheses, the hydrolysis stages of which result in the formation of salt-containing and consequently environment polluting waste waters. In addition, the preparation by means of n-butyllithium re-quires special safety measures (because of the sponteneous ;nflammability of the latter in air).
Another preparation method for fluorobenzaldehydes is the subject o~ EP-A-0,164,619. According to the latter, chloro-benzonitriles or chlorobenzoyl halides are reacted with KF at elevated temperature in a dipolar aprotic solvent, in particular sulfolane (= tetrahydrothiophen-S,S-dioxide), and the fluorobenzonitrile or fluorobenzoyl halide respec-tively obtained is optionally converted in a manner known per se into other aromatic fluoro compounds, inter alia, 3û also into fluorobenzaldehydes. Consequently, 2,4,5-tri-fluorobenzaldehyde is obtained by first reacting 2,4,5-trichlorobenzonitrile with 3 KF to form 2,4,5-trifluoro-benzonitrile and then proceeding as follows, the specified path from the fluorinated nitrile to the aldehyde corres-ponding to the reaction sequence described on page 6 ofthe EP-A:
1~98:~S
Various processes are known for the preparation of fluoro-benzaldehydes. Thus, for example, German Auslegeschrift 2,039,426 (Example 7) describes the preparation of 2,4-and 3,4-difluorobenzaldehyde in 70 and 76% yield respec-tively; the reaction proceeds according to the following formulation:
o CH3 CHBr2 C ~H
~F 2 Br2, light ~F Hydrolysj5~CaC03~ H20) ~F
F F F
According to EP-A-0,117,100 (Preparation 3, page 16), 2,4-difluorobenzaldehyde is obtained in good yield also by the follo~ing path:
o Br Li C ~ H
~ 1 1) Dimethylformamide ~ F ~ F 2) HydrolYsis ~ F
~-Butyllithium ~ ~H20~NH4Cl) F F F
The starting products for these reactions can be obtained, for example, by a single or multiple Balz-Schiemann reac-tion. The term "Balz-Schiemann reaction" is understood to mean the thermal decomposition of aromatic diazonium ~L
lZ~ lS
tetrafluoroborates to the correspond;ng aromatic fluorine compounds. The formulation, for example, for the prepara-tion of 2,4-difluorotoluene, may be reproduced as follows:
S ~
NH2 1) Diazotiza~ion(HNo2lH~l BF~N--N
CH3 ~NH2 2) }D3F4 N-N(~)BF~) F
Heating Z~
~ C~3-~ ~-P ~ 2 N2 ~ 2 BF3 Starting from common starting products, these processes consequently involve multi-stage syntheses, the hydrolysis stages of which result in the formation of salt-containing and consequently environment polluting waste waters. In addition, the preparation by means of n-butyllithium re-quires special safety measures (because of the sponteneous ;nflammability of the latter in air).
Another preparation method for fluorobenzaldehydes is the subject o~ EP-A-0,164,619. According to the latter, chloro-benzonitriles or chlorobenzoyl halides are reacted with KF at elevated temperature in a dipolar aprotic solvent, in particular sulfolane (= tetrahydrothiophen-S,S-dioxide), and the fluorobenzonitrile or fluorobenzoyl halide respec-tively obtained is optionally converted in a manner known per se into other aromatic fluoro compounds, inter alia, 3û also into fluorobenzaldehydes. Consequently, 2,4,5-tri-fluorobenzaldehyde is obtained by first reacting 2,4,5-trichlorobenzonitrile with 3 KF to form 2,4,5-trifluoro-benzonitrile and then proceeding as follows, the specified path from the fluorinated nitrile to the aldehyde corres-ponding to the reaction sequence described on page 6 ofthe EP-A:
1~98:~S
Cl~ COOH C--Cl ~ Hydrolysis If~ so 5 F ~ ~ ~ F ~ ~ F
C ~F 1) ~H CH2~l L alkalifluoride ~[~ 2) HydrolYsis F~
CH2Cl CHCl2 C ~H
FJ~ 2 ~ F ~ Hydrolysis F F F
As is evident, this synthesis requires a multiplicity of reaction steps.
In the effort to provide a simpler preparation method for fluorobenzaldehydes, it has now been found that this object is achieved by reacting chlorobenzaldehydes with alkali fluorides in an aprotic reaction medium. The object of the invention is therefore a process for the preparation ZS of fluorobenzaldehydes by applying the chlorine/fluorine exchange reaction to aromatic compounds using alkali fluoride in dipolar aprotic medium; this process is a pro-cess wherein chlorobenzaldehyde is used for said chlorine/
fluorine exchange reaction. The aldehyde yields in this case are normally around about 70~ and over. Starting from common starting products, the process provides a simple and single-stage synthesis method for fluorobenzal-dehydes, which method produces no waste water.
35 The achievement of this reaction is extremely surprising because, according to the abovementioned EP-A-0,164,619, it had to be assumed that fluorobenzaldehydes cannot be prepared in a single reaction stage from the corresponding chlorobenzaldehydes by chlorine/fluorine exchange using alkali fluoride in an aprotic medium, but that fluoroben-zaldehydes can only be prepared in a fairly costly manner in several reaction steps from those chlorinated aromatic compounds which have no CHO group. This also appears un-derstandable because alkali fLuorides are known as strong bases in an aprotic medium in which, in contrast to aqueous systems, virtually no solvation of the fluoride occurs (cf.
the review by G.G. Yakobson and N.E. Akhmetova in Synthesis, 1983, pages 169 and 170 ("..... alkali metal fluorides are rather strong bases ...", cf. page 169, left-hand column, paragraph 1 and page 170, paragraph 2: "The basic properties of alkali metal fluorides were first revealed in dehydrohalo-genation reactions")). However, aldehydes are known to be by no means stable towards strong bases. A reaction of alde-hydes with bases is, for example, the so-called Cannizzaro reaction (Oxidation-reduction of aldehydes in the presence of bases). A reaction with the activated hydrogen atoms in the ~ position with respect to CO, SO or S2 groups of the aprotic solvent used is also conceivable.
To carry out the reaction, all the possible chlorobenzal-dehydes can in principle be used; preferred is the use of chlorobenzaldehydes of formula (I) R3~ 1 (I) in which R1, R2 and R3 represent, independently of each other, H, F and/or Cl, but at least one of the radicals is chlorine and at least one of the radicals R1 and R3 is hydrogen, and S1 and S2, independently of each other, = H
and/or are radicals which reduce the electron density on the benzene ring, preferably = H.
Exemplary S1 and S2 radicals which reduce the electron .,ti density on the benzene ring by mesomeric or inductive effects (cf. Organikum VE~, published by Deutscher Verlag der Wissenschaften, 1973, sections 5.1.2 and 5.2.1) are -N02, -CN and -CHO.
Exemplary starting compounds for the reaction according to the invention are therefore o-, m- and p-chlorobenzal-dehyde, 2,4-dichloro, 2,4,6-trichlorobenzaldehyde, 2,4-dichloro-3-nitrobenzaldehyde, 2-chloro-4-fluoro- and 2-fluoro-4-chlorobenzaldehyde, it being possible also to use the latter as a mixture, especially as the result in a uniform final product. A particularly preferred start-ing compound is 2,4-dichlorobenzaldehyde.
~5 For the exchange of the chlorine atoms in the starting compound, 1 mol o~ alkalifluoride is stoichiometrically required per chlor;ne atom. If it is intended to exchange all the chlorine atoms in the starting chlorobenzaldehyde, it is advantageous to use up to about 200%, in particular about 100-12QX of the stoichiometric quantity of alkali fluoride. The use of larger alkali fluoride quantities is possible but does not offer any particular advantage.
In the case of benzaldehydes containing several chlorine atoms, the reactiDn may be carried out in a manner such that a predominantly partially fluorinated product is produced by using a smaller quantity of alkali fluoride in the reaction than is required for the exchange of all the chlorine atoms.
As alkali fluoride, use is made, for exampLe, of sodium fluoride or of alkali fluorides on their own or as mix-tures with the simple alkali fluorides. Preferred, however, is potassium fluoride or a mixture of the latter with rubidium and/or cesium fluoride in any desired molar ratio; particularly preferred is a mixture containing only a small (catalytic) proportion of rubidium and/or cesium fluoride (up to about S mol-%).
1.S
Suitable as solvents for the reaction are in principle a(l the possible dipolar aprotic solvents, preferably tertiary carboxylic acid amides such 2S dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N,N,N',N'-tetra-methylurea, N,N'-dimethylimidazolidin-2-one, sulfoxides such as dimethylsulfoxide and suLfones such as dimethyl-sulfone, diphenylsulfone and sulfolane. Particularly preferred are N-methylpyrrolidone, dimethylsulfoxide and dimethylsulfone, in particular, however, solfolane. The solvents can be used both individually and also mixed with each other.
The initial concentration of the aldehyde may be in a wide range; preferably, it is about 0.5-3 mol/kg of sol-vent, in particular about 1-1.7 mol/kg of dipolar aprotic medium (solvent).
The reaction is able to proceed in a wide temperature range. Expediently, temperatures between about 1Z0 and 250C, in particular between about 180 and 230C, are employed.
The reaction acccrding to the invention is preferably car-ried out in a manner such that the starting chlorobenzal-dehyde is heated with the solvent and the alkali fluoride for a prolonged time wh;le stirring and in a protective gas atmosphere, for example, argon, preferably, however, nitrogen. ~he course of the reaction is monitored, for example, by gas chromatography. After the desired degree of conversion has been reached, the product is worked up:
preferably, the inorganic part (alkali halide) ;s separa-ted off by filtering off under an inert gas atmosphere.
The product contained in the organic phase is then puri-fied, preferably by rectification under reduced pressure.
The invention is explained in more detail by the examples below, alL operations being carried out under N2 as pro-tective gas.
Exa~ples 1) 175 9 (1 mol) of 2,4-dichlorobenzaldehyde were heated together with 1,000 9 of sulfolane and 151 9 (2.6 mol) of potassium chloride for 15 h at 210-215C. The reaction mixture was thoroughly mixed during the entire duration of the reaction by a powerful stirring mechanism in order to prevent the insoluble salts settling. Cooling was then carried out to room temperature and the inorganic constituents were seParated off by means of a suction filter covered with a blanket of nitrogen. Rinsing was carried out twice using 100 9 of fresh sulfolane in each case. From the filtrate 96.6 9 = 68% of theory of 2,4-difluorobenzaldehyde with a boiling point of 70.5C
(40 mbar) was obtained by rectification under reduced pressure in a coLumn containing approx. 20 theoretical trays. Solidification point: approximately 2C.
2) 56 9 (0.4 mol) of 4-chlorobenzaldehyde were heated together with 200 9 of 1,3-dimethylimidazolidin-2-one, 29.5 9 of potassium fluoride and 4.03 9 of cesium fluoride (5 mol-X referred to potassium fluoride) at 215C for 20 h while stirring vigorously. 12.7% by weight (32.4 9) of 4-fluorobenzaldehyde, which is equivalent to 65.2%, and 4.3% by weight (= 11.0 9) of 4-chlorobenzaldehyde, which ;s equivalent to 19.6%, referred in each case to the starting material, were detected by gas chromatography in the reaction mixture. The working up was carried out as described in Example 1.
3) 158.5 9 (1 mol) of a mixture of 56% of 4-chloro-2-fluoro-benzaldehyde and 44% of 2-chloro-4-fluorobenzalde-hyde were heated together with 700 9 of sulfolane and 75 9 (1.29 mol) of potassium fluoride at 215C for 10 h. The working up was carried out as in Example 1. 99.5% of 2,4-difluorobenzaldehyde equivalent to 70% of the feed-stock was obtained.
C ~F 1) ~H CH2~l L alkalifluoride ~[~ 2) HydrolYsis F~
CH2Cl CHCl2 C ~H
FJ~ 2 ~ F ~ Hydrolysis F F F
As is evident, this synthesis requires a multiplicity of reaction steps.
In the effort to provide a simpler preparation method for fluorobenzaldehydes, it has now been found that this object is achieved by reacting chlorobenzaldehydes with alkali fluorides in an aprotic reaction medium. The object of the invention is therefore a process for the preparation ZS of fluorobenzaldehydes by applying the chlorine/fluorine exchange reaction to aromatic compounds using alkali fluoride in dipolar aprotic medium; this process is a pro-cess wherein chlorobenzaldehyde is used for said chlorine/
fluorine exchange reaction. The aldehyde yields in this case are normally around about 70~ and over. Starting from common starting products, the process provides a simple and single-stage synthesis method for fluorobenzal-dehydes, which method produces no waste water.
35 The achievement of this reaction is extremely surprising because, according to the abovementioned EP-A-0,164,619, it had to be assumed that fluorobenzaldehydes cannot be prepared in a single reaction stage from the corresponding chlorobenzaldehydes by chlorine/fluorine exchange using alkali fluoride in an aprotic medium, but that fluoroben-zaldehydes can only be prepared in a fairly costly manner in several reaction steps from those chlorinated aromatic compounds which have no CHO group. This also appears un-derstandable because alkali fLuorides are known as strong bases in an aprotic medium in which, in contrast to aqueous systems, virtually no solvation of the fluoride occurs (cf.
the review by G.G. Yakobson and N.E. Akhmetova in Synthesis, 1983, pages 169 and 170 ("..... alkali metal fluorides are rather strong bases ...", cf. page 169, left-hand column, paragraph 1 and page 170, paragraph 2: "The basic properties of alkali metal fluorides were first revealed in dehydrohalo-genation reactions")). However, aldehydes are known to be by no means stable towards strong bases. A reaction of alde-hydes with bases is, for example, the so-called Cannizzaro reaction (Oxidation-reduction of aldehydes in the presence of bases). A reaction with the activated hydrogen atoms in the ~ position with respect to CO, SO or S2 groups of the aprotic solvent used is also conceivable.
To carry out the reaction, all the possible chlorobenzal-dehydes can in principle be used; preferred is the use of chlorobenzaldehydes of formula (I) R3~ 1 (I) in which R1, R2 and R3 represent, independently of each other, H, F and/or Cl, but at least one of the radicals is chlorine and at least one of the radicals R1 and R3 is hydrogen, and S1 and S2, independently of each other, = H
and/or are radicals which reduce the electron density on the benzene ring, preferably = H.
Exemplary S1 and S2 radicals which reduce the electron .,ti density on the benzene ring by mesomeric or inductive effects (cf. Organikum VE~, published by Deutscher Verlag der Wissenschaften, 1973, sections 5.1.2 and 5.2.1) are -N02, -CN and -CHO.
Exemplary starting compounds for the reaction according to the invention are therefore o-, m- and p-chlorobenzal-dehyde, 2,4-dichloro, 2,4,6-trichlorobenzaldehyde, 2,4-dichloro-3-nitrobenzaldehyde, 2-chloro-4-fluoro- and 2-fluoro-4-chlorobenzaldehyde, it being possible also to use the latter as a mixture, especially as the result in a uniform final product. A particularly preferred start-ing compound is 2,4-dichlorobenzaldehyde.
~5 For the exchange of the chlorine atoms in the starting compound, 1 mol o~ alkalifluoride is stoichiometrically required per chlor;ne atom. If it is intended to exchange all the chlorine atoms in the starting chlorobenzaldehyde, it is advantageous to use up to about 200%, in particular about 100-12QX of the stoichiometric quantity of alkali fluoride. The use of larger alkali fluoride quantities is possible but does not offer any particular advantage.
In the case of benzaldehydes containing several chlorine atoms, the reactiDn may be carried out in a manner such that a predominantly partially fluorinated product is produced by using a smaller quantity of alkali fluoride in the reaction than is required for the exchange of all the chlorine atoms.
As alkali fluoride, use is made, for exampLe, of sodium fluoride or of alkali fluorides on their own or as mix-tures with the simple alkali fluorides. Preferred, however, is potassium fluoride or a mixture of the latter with rubidium and/or cesium fluoride in any desired molar ratio; particularly preferred is a mixture containing only a small (catalytic) proportion of rubidium and/or cesium fluoride (up to about S mol-%).
1.S
Suitable as solvents for the reaction are in principle a(l the possible dipolar aprotic solvents, preferably tertiary carboxylic acid amides such 2S dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N,N,N',N'-tetra-methylurea, N,N'-dimethylimidazolidin-2-one, sulfoxides such as dimethylsulfoxide and suLfones such as dimethyl-sulfone, diphenylsulfone and sulfolane. Particularly preferred are N-methylpyrrolidone, dimethylsulfoxide and dimethylsulfone, in particular, however, solfolane. The solvents can be used both individually and also mixed with each other.
The initial concentration of the aldehyde may be in a wide range; preferably, it is about 0.5-3 mol/kg of sol-vent, in particular about 1-1.7 mol/kg of dipolar aprotic medium (solvent).
The reaction is able to proceed in a wide temperature range. Expediently, temperatures between about 1Z0 and 250C, in particular between about 180 and 230C, are employed.
The reaction acccrding to the invention is preferably car-ried out in a manner such that the starting chlorobenzal-dehyde is heated with the solvent and the alkali fluoride for a prolonged time wh;le stirring and in a protective gas atmosphere, for example, argon, preferably, however, nitrogen. ~he course of the reaction is monitored, for example, by gas chromatography. After the desired degree of conversion has been reached, the product is worked up:
preferably, the inorganic part (alkali halide) ;s separa-ted off by filtering off under an inert gas atmosphere.
The product contained in the organic phase is then puri-fied, preferably by rectification under reduced pressure.
The invention is explained in more detail by the examples below, alL operations being carried out under N2 as pro-tective gas.
Exa~ples 1) 175 9 (1 mol) of 2,4-dichlorobenzaldehyde were heated together with 1,000 9 of sulfolane and 151 9 (2.6 mol) of potassium chloride for 15 h at 210-215C. The reaction mixture was thoroughly mixed during the entire duration of the reaction by a powerful stirring mechanism in order to prevent the insoluble salts settling. Cooling was then carried out to room temperature and the inorganic constituents were seParated off by means of a suction filter covered with a blanket of nitrogen. Rinsing was carried out twice using 100 9 of fresh sulfolane in each case. From the filtrate 96.6 9 = 68% of theory of 2,4-difluorobenzaldehyde with a boiling point of 70.5C
(40 mbar) was obtained by rectification under reduced pressure in a coLumn containing approx. 20 theoretical trays. Solidification point: approximately 2C.
2) 56 9 (0.4 mol) of 4-chlorobenzaldehyde were heated together with 200 9 of 1,3-dimethylimidazolidin-2-one, 29.5 9 of potassium fluoride and 4.03 9 of cesium fluoride (5 mol-X referred to potassium fluoride) at 215C for 20 h while stirring vigorously. 12.7% by weight (32.4 9) of 4-fluorobenzaldehyde, which is equivalent to 65.2%, and 4.3% by weight (= 11.0 9) of 4-chlorobenzaldehyde, which ;s equivalent to 19.6%, referred in each case to the starting material, were detected by gas chromatography in the reaction mixture. The working up was carried out as described in Example 1.
3) 158.5 9 (1 mol) of a mixture of 56% of 4-chloro-2-fluoro-benzaldehyde and 44% of 2-chloro-4-fluorobenzalde-hyde were heated together with 700 9 of sulfolane and 75 9 (1.29 mol) of potassium fluoride at 215C for 10 h. The working up was carried out as in Example 1. 99.5% of 2,4-difluorobenzaldehyde equivalent to 70% of the feed-stock was obtained.
Claims (19)
1. A process for the production of fluorobenzaldehydes which comprises reacting a chlorobenzaldehyde with an alkali fluoride in a dipolar aprotic medium.
2. A process as claimed in claim 1, wherein the chloro-benzaldehyde has the formula (I) , wherein R1, R2 and R3 each are equal or different and are hydrogen, fluorine or chlorine, at least one being however chlorine and S1 and S2 are equal or different and represent hydrogen or a radical which reduces the electron density.
3. A process as claimed in claim 1, wherein the alkali fluoride is employed in an amount between the stoichiometric amount and up to 200 %, related to the stoichiometric amount necessary for replacing all chlorine atoms of the chloro-benzaldehyde.
4. A process as claimed in claim 1, wherein the alkali fluoride is employed in a smaller amount than is necessary for the replacement of all chlorine substituents, to yield a partially fluorinated product only.
5. A process as claimed in claim 2 or 3 or 4, wherein both S1 and S2 and at least one of R1 and R3 represent hydrogen.
6. A process as claimed in claim 2 or 3 or 4, wherein the chlorobenzaldehyde is 2,4-dichlorobenzaldehyde.
7. A process as claimed in claim 1 or 2 or 3, wherein the the alkali fluoride is employed in an amount in the range from about 100 to 120 % of the stoichiometric amount necessary for replacing all chlorine atoms.
8. A process as claimed in claim 1 or 2 or 3, wherein the alkali fluoride employed is potassium fluoride.
9. A process as claimed in claim 1 or 2 or 3, wherein a mixture of potassium fluoride and at least one fluoride of rubidium and cesium is applied.
10. A process as claimed in claim 1 or 2 or 3, wherein a mixture of potassium fluoride and at least one fluoride of rubidium and cesium is applied and the total amount of the fluorides of rubidium and cesium is at most 5 mol-%.
11. A process as claimed in claim 1 or 2 or 3, wherein the dipolar aprotic medium is a tertiary amide of a carboxylic acid, a sulfoxide or a sulfone or a mixture thereof.
12. A process as claimed in claim 1 or 2 or 3, wherein the dipolar aprotic medium is N-methylpyrrolidone.
13. A process as claimed in claim 1 or 2 or 3, wherein the dipolar aprotic medium is at least one of dimethylsulfoxide and dimethylsulfone.
14. A process as claimed in claim 1 or 2 or 3, wherein the dipolar aprotic medium is sulfolane.
15. A process as claimed in claim 1 or 2 or 3, which is carried out at a temperature in the range from about 120 to 250°C.
16. A process as claimed in claim 1 or 2 or 3, which is carried out at a temperature in the range from about 180 to 230°C.
17. A process as claimed in claim 1 or 2 or 3, wherein the initial concentration of the aldehyde is in a range from about 0.5 to 3 mol/kg of dipolar aprotic medium.
18. A process as claimed in claim 1 or 2 or 3, wherein the initial concentration of the aldehyde is in the range from about 1 to 1.7 mol/kg of dipolar aprotic medium.
19. A process as claimed in claim 1 or 2 or 3 which is carried out under a protective gas.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3637156.4 | 1986-10-31 | ||
| DE3637156A DE3637156C2 (en) | 1986-10-31 | 1986-10-31 | Process for the preparation of fluorobenzaldehydes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1298315C true CA1298315C (en) | 1992-03-31 |
Family
ID=6312911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000550628A Expired - Fee Related CA1298315C (en) | 1986-10-31 | 1987-10-30 | Process for the preparation of fluorobenzaldehydes |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0265854B2 (en) |
| JP (1) | JPS63122643A (en) |
| CA (1) | CA1298315C (en) |
| DE (2) | DE3637156C2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3820979A1 (en) * | 1988-06-22 | 1989-12-28 | Basf Ag | METHOD FOR THE PRODUCTION OF FLUORINE-SUBSTITUTED BENZALDEHYDES |
| US4847442A (en) * | 1988-07-18 | 1989-07-11 | Allied-Signal Inc. | Process for the preparation of difluorobenzenes |
| DE3915495A1 (en) * | 1989-05-12 | 1990-11-15 | Bayer Ag | NUCLEAR-FLUORED TRIFLUORMETHYLBENZALDEHYDE |
| US5191126A (en) * | 1991-07-16 | 1993-03-02 | Hoechst Aktiengesellschaft | Process for the preparation of difluorobenzaldehydes |
| DE59310066D1 (en) * | 1992-11-04 | 2000-08-03 | Clariant Gmbh | Process for the preparation of fluorinated benziles |
| DE19738196A1 (en) * | 1997-09-02 | 1999-03-04 | Hoechst Ag | Process for the preparation of fluorine-containing compounds in high purity |
| DE19836698A1 (en) * | 1998-08-13 | 2000-02-17 | Bayer Ag | Process for the preparation of fluorinated benzyl alcohols and aldehydes |
| WO2022070992A1 (en) * | 2020-09-29 | 2022-04-07 | 東レ株式会社 | Method for producing fluorinated aromatic aldehyde |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE117100C (en) * | ||||
| BE754556A (en) * | 1969-08-08 | 1971-02-08 | Merck & Co Inc | INDENYL-ACETIC ACIDS AND PROCESS FOR THE |
| DE3111421A1 (en) * | 1981-03-24 | 1982-10-07 | Bayer Ag, 5090 Leverkusen | METHOD FOR THE PRODUCTION OF SUBSTITUTED FLUORNITRO-BENZALDEHYDES, IF ANY |
| EP0117100B1 (en) * | 1983-02-16 | 1986-12-10 | Pfizer Limited | Triazole antifungal agents |
| GB8316384D0 (en) * | 1983-06-16 | 1983-07-20 | Sanders B | Hose |
| FR2556339B1 (en) * | 1983-12-13 | 1986-05-16 | Atochem | CATALYTIC PROCESS FOR THE PREPARATION OF TRIFLUOROACETALDEHYDE |
| DE3420796A1 (en) * | 1984-06-04 | 1985-12-05 | Bayer Ag, 5090 Leverkusen | 2,4,5-TRIHALOGEN OR 2,3,4,5-TETRAHALOGENBENZENE DERIVATIVES AND METHOD FOR THE PRODUCTION THEREOF |
-
1986
- 1986-10-31 DE DE3637156A patent/DE3637156C2/en not_active Expired - Lifetime
-
1987
- 1987-10-23 DE DE8787115530T patent/DE3769076D1/en not_active Expired - Fee Related
- 1987-10-23 EP EP87115530A patent/EP0265854B2/en not_active Expired - Lifetime
- 1987-10-29 JP JP62271978A patent/JPS63122643A/en active Pending
- 1987-10-30 CA CA000550628A patent/CA1298315C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0265854B2 (en) | 1999-03-24 |
| EP0265854B1 (en) | 1991-04-03 |
| DE3637156C2 (en) | 1995-12-21 |
| EP0265854A1 (en) | 1988-05-04 |
| JPS63122643A (en) | 1988-05-26 |
| DE3637156A1 (en) | 1988-05-05 |
| DE3769076D1 (en) | 1991-05-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4684734A (en) | Method for manufacture or organic fluorine compounds | |
| EP0018606B1 (en) | Direct fluorination of etherified hydroxy group-bearing aromatic compounds | |
| US4590315A (en) | Process for the preparation of halo aromatic compounds | |
| CA1298315C (en) | Process for the preparation of fluorobenzaldehydes | |
| EP0253836B1 (en) | Preparation of fluoroaromatic compounds in dispersion of potassium fluoride | |
| JPH02218630A (en) | Preparation of halofluorobenzene | |
| US5227531A (en) | Process for the preparation of fluorobenzaldehydes | |
| US4849552A (en) | Preparation of fluoroaromatic compounds in dispersion of potassium fluoride | |
| US4837364A (en) | Processes for preparing pentafluoroethoxy- and pentafluoroethylthiobenzene drivatives | |
| CA2189945A1 (en) | Process for preparing fluorinated aromatics | |
| JPH035436A (en) | Nucleus-fluorianted trifluoromethylbenzaldehyde | |
| US4351777A (en) | Preparation of fluorobenzonitriles | |
| US5138099A (en) | Synthesis of fluorobenzaldehydes | |
| JPH024580B2 (en) | ||
| WO2015001020A1 (en) | Process for fluorination of sulphonyl halide compounds | |
| EP0249257A1 (en) | Preparation of aryl halides | |
| EP0355719B1 (en) | Process for producing chlorofluorobenzenes | |
| JPH04224528A (en) | Method for production of fluorine containing ethane derivative, catalytic mixture and fluorinated hydrocarbon solution | |
| JPH06107650A (en) | Production of hexafluoropropene oxide | |
| US4952719A (en) | Process for the preparation of halo aromatic compounds | |
| CA1157884A (en) | Process for the preparation of trifluoromethylbenzoyl halides | |
| JPS63502182A (en) | Catalytic production method for fluoroaromatic compounds using branched chain alkylpyridinium salts | |
| US20010002425A1 (en) | Process for production of 1,4-bis (difluoroalkyl) benzene derivative | |
| JPH05213810A (en) | Preparation of difluorobenzaldehyde | |
| JPH06228042A (en) | Fluorobenzyl and its preparation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |