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1. WO1987004151 - PREPARATION DE COMPOSES FLUOROAROMATIQUES DANS UNE DISPERSION DE FLUORURE DE POTASSIUM

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

WHAT IS CLAIMED IS:
1. In a process for preparing a fluoroaromatic compound by reaction of a corresponding chloroaromatic compound with potassium fluoride in an
aprotic polar organic solvent under substantially
anhydrous halide-exchange conditions in the presence of a catalyzing amount of a phase-transfer catalyst,
the improvement which comprises effecting the reaction i n a substantially anhydrous dispersion of ultra-fine particulate potassium fluoride in an aprotic polar organic solvent, said dispersion prepared by a method comprising
(a) preparing a solution of potassium fluoride in methanol,
(b) preparing a mixture by adding to said solution (i) an aromatic compound selected from aromatic hydrocarbons, aromatic chlorohydrocarbons and aromatic fluorohydrocarbons, said aromatic compound being an azeotrope former with methanol, and (ii) an aprotic polar solvent having a boiling point at a selected pressure at least 30ºC higher than the boiling point at said pressure of said aromatic compound,
(c) distilling said mixture at said pressure to prepare a distillation residue consisting essentially of said dispersion.
2. The process of Claim 1 wherein said aromatic compound is selected from the group consisting of toluene, benzene, xylene, isopropyl benzene, chlorobenzene and fluorobenzene.
3. The process of Claim 2 wherein said compound is toluene.
4. The process of Claim 1 wherein said aprotic dipolar solvent is selected from the group consisting of sulfolane, N-methylpyrrolidone, dimethyl formamide and dimethylsuIfoxide.

5. The process of Claim 4 wherein said solvent is sulfolane.

6. The process of Claim 1 wherein said
potassium fluoride from which said solution is formed
contains a minor amount of water, said aromatic compound additionally forms an azeotrope with water, and said
distillate contains substantially all the water initially contained in said solution.

7. The process of Claim 1 wherein the chloroaromatic compound comprises an aromatic ring, at least one chlorine atom as a substituent on the aromatic ring and at least one
activating substituent located in an activating position on the ring for facilitating nucleophilic substitution of fluorine for the chlorine, the activating substituent being an
electron-withdrawing agent selected from the group consisting of nitro; cyano; trifluoromethyl; chlorocarbonyl; fluorocarbonyl; phenylcarbonyl wherein the phenyl moiety is
unsubstituted or substituted with a substituent other than agents which are at least moderately strong electron-releasing agents; phenylsulfonyl wherein the phenyl moiety is
unsubstituted or substituted with a substituent other than agents which are at least moderately strong electron-releasing agents; and a combination of three, four or five additional chlorine atoms.

8. The process of Claim 1 wherein the chloroaromatic compound is selected from the group consisting of
(a) 2-chlorobenzonitrile
(b) 4-chlorobenzonitrile
(c) 2-chlorobenzoyl chloride
( d) 4-chlorobenzoyl chloride
(e) 2-chlorobenzoyl fluoride
(f) 4-chlorobenzoyl fluoride
(g) 2-chloro-benzotrifluoride
(h) 4-chloro-benzotrifluoride
(i) tetrachlorobenzene
(j) pentachlorobenzene
(k) hexachlorobenzene
(l) (4,4'-dichloro-)diphenylsulfone
(m) 4,4'-dichlorobenzophenone
(n) 3-chloro-phthalic anhydride
(o) 4-chloro-phthalic anhydride
(P) 3-chloro-phthaloyl dichloride
(q) 4-chloro-phthaloyl dichloride
(r) 1,4-dichloroanthracene-9,10-dione
(s) 3-chloro-4-(trifluoromethyl)pyridine
(t) 3-chloro-4-cyanopyridine
(u) 3-chloro-4-nitropyridine.
(v) 2-chloronitrobenzene
(w) 2,3-dichloronitrobenzene
(x) 4-chloronitrobenzene
(y) 2,4-dichloronitrobenzene and
(z) 2,4,5-trichloronitrobenzene

9. The process of Claim 1 wherein the chloroaromatic compound is a chloronitrobenzene.