EP0000542A1 - Process for the preparation of trifluoromethyl phenols - Google Patents

Abstract

A process has been found for the preparation of trifluoromethylphenols, which is based on an aromatic halogen compound which has at least one trifluoromethyl group and at least one substituent; which favors the exchange of halogen for a hydroxyl group, and optionally carries further substituents, and reacting these in alcoholic solution with aqueous alkali metal hydroxide in the presence of quaternary onium salts. New substituted trifluoromethylphenols can be prepared by the process according to the invention.

Description

The invention relates to a process for the preparation of phenols having a trifluoromethyl group.

It is known to produce, for example, 2-nitro-4-trifluoromethylphenol by reacting 4-chloro-3-nitro-benzotrifluoride with sodium hydroxide solution in dimethyl sulfoxide (J. org. Chem. 36, 242 (1971)).

According to another process, trifluoromethylphenols are obtained by cleaving the corresponding methoxy compounds with pyridine hydrochloride at 210 ° C. (J. org.Chem. 27, 4660 (1962); in this process, the methoxy compounds are prepared from chloronitrobenzotrifluorides in a preceding process step.

in der

• X Halogen,
• 3 R¹, R² und R Wasserstoff, Trifluormethyl oder einen Substituenten, der den Austausch von X gegen die Hydroxylgruppe begünstigt, und
• Y Wasserstoff, ein Halogen oder Alkoxy

bedeuten,
wobei von den Substituenten R¹, R² und R³ mindestens einer eine Trifluormethylgruppe und mindestens einer einen
Substituenten, der den Austausch des Restes X gegen eine Hydroxylgruppe begünstigt, darstellt,
in alkoholischer Lösung mit überschüssigem wäßrigem Alkalihydroxid in Gegenwart von quartären Oniumsalzen umsetzt.A process for the preparation of trifluoromethylphenols has been found, in which compounds of the formula

in the

• X halogen,
• 3 R ¹ , R ² and R are hydrogen, trifluoromethyl or a substituent which promotes the exchange of X for the hydroxyl group, and
• Y is hydrogen, a halogen or alkoxy

mean,
wherein of the substituents R ¹ , R ² and R ³ at least one is a trifluoromethyl group and at least one is one
Represents substituents which favor the exchange of the radical X for a hydroxyl group,
in alcoholic solution with excess aqueous alkali hydroxide in the presence of quaternary onium salts.

Halogens (X) can be fluorine, chlorine, bromine or iodine, preferably fluorine or chlorine.

• die Nitrogruppe,
• die Alkylsulfonylgruppe, deren Alkylrest bevorzugt ein geradkettiger oder verzweigter niederer Alkylrest mit 1-8 Kohlenstoffatomen sein kann, wie beispielsweise Methyl, Äthyl, Propyl, Isopropyl oder isomeres Butyl, Hexyl oder Octyl, die Arylsulfongruppe, deren Arylrest bevorzugt Phenyl.oder ein beispielsweise durch Chlor oder Methyl substituiertes Phenyl sein kann,
• die Trifluormethylgruppe,
• die Carboxylgruppe,
• die Carbonsäureestergruppe, deren Alkoholkomponente ein geradkettiger oder verzweigter niederer aliphatischer Alkohol

mit 1-8 Kohlenstoffatomen sein kann, wie beispielsweise Methanol, Äthanol, Propanol, Isopropanol,oder die isomeren Butanole, Hexanole oder Octanole.Substituents R ¹ , _R 2 or R ³ which favor the exchange of the radical X for a hydroxyl group are, for example, second-order substituents (Beyer, Textbook of Organic Chemistry, Leipzi ^g 1962, p. 373). Examples include:

• the nitro group,
• the alkylsulfonyl group, the alkyl radical of which can preferably be a straight-chain or branched lower alkyl radical having 1-8 carbon atoms, such as, for example, methyl, ethyl, propyl, isopropyl or isomeric butyl, hexyl or octyl, the arylsulfone group, the aryl radical of which is preferably phenyl or, for example, by chlorine or can be methyl-substituted phenyl,
• the trifluoromethyl group,
• the carboxyl group,
• the carboxylic acid ester group, the alcohol component of which is a straight-chain or branched lower aliphatic alcohol

can be with 1-8 carbon atoms, such as methanol, ethanol, propanol, isopropanol, or the isomeric butanols, hexanols or octanols.

As the halogen atom (Y) fluorine, chlorine, bromine or iodine, preferably chlorine or bromine, may be mentioned.

The alkoxy group (Y) preferably contains alkyl radicals having 1 to 4 carbon atoms, for example the methyl, ethyl, propyl, isopropyl, butyl or tert-butyl radical.

in der
X' ein Fluor- oder ein Chloratom bedeutet und die Reste R¹,R²,R³ die obengenannte Bedeutung haben,
genannt.Preferred compounds of the formula (I) are compounds of the formula II

in the
X 'represents a fluorine or a chlorine atom and the radicals R ¹ , R ² , R ^{3 have} the abovementioned meaning,
called.

Compounds of the formula I are known and can be prepared by nitrating chlorotrifluoromethylbenzene with nitric acid / sulfuric acid (J.org.Chem. 26, 2707 (1961)).

• 4-Chlor-3-nitro-benzotrifluorid
• 2-Chlor-5-nitro-benzotrifluorid
• 3,4-Dichlor-5-nitro-benzotrifluorid
• 2,3-Dichlor-5-nitro-benzotrifluorid
• 2,4-Dichlor-5-nitro-benzotrifluorid
• 6-Chlor-3-nitro-5-trifluormethyl-benzoesäure
• 2-Chlor-3-nitro-5-trifluormethyl-benzoesäure
• 4-Brom-3-nitro-benzotrifluorid
• 2-Brom-5-nitro-benzotrifluorid
• 2-Chlor-3-methoxy-5-nitro-benzotrifluorid
• 2-Methoxy-4-chlor-5-nitro-benzotrifluorid.

The following compounds of the formula (I) may be mentioned, for example:

• 4-chloro-3-nitro-benzotrifluoride
• 2-chloro-5-nitro-benzotrifluoride
• 3,4-dichloro-5-nitro-benzotrifluoride
• 2,3-dichloro-5-nitro-benzotrifluoride
• 2,4-dichloro-5-nitro-benzotrifluoride
• 6-chloro-3-nitro-5-trifluoromethyl-benzoic acid
• 2-chloro-3-nitro-5-trifluoromethyl-benzoic acid
• 4-bromo-3-nitro-benzotrifluoride
• 2-bromo-5-nitro-benzotrifluoride
• 2-chloro-3-methoxy-5-nitro-benzotrifluoride
• 2-methoxy-4-chloro-5-nitro-benzotrifluoride.

Alcohols with a lower unbranched or branched alkyl radical can be used as solvents for the process according to the invention. Alcohols whose unbranched or branched alkyl radical has 1 to 4 carbon atoms, such as methanol, ethanol, propanol, isopropanol, the various isomeric butanols, glycol and glycol monomethyl ether, are preferred.

The amount of the solvent may vary within wide limits, so, for example, at 1 _G ew. part a compound of formula (I) 1 to 20 parts by weight, preferably 2 to 8 parts by weight, solvents.

Sodium or potassium hydroxide are preferably used as alkali metal hydroxides for the process according to the invention. They are generally used in the form of their aqueous solutions which contain, for example, 30-50% by weight of alkali metal hydroxide. However, the sodium or potassium hydroxide can also be added in solid form to the aqueous alcoholic solution. The alkali metal hydroxides are generally used in excess, the use of about three times the molar amount based on the conversion of the halogen atom to the phenolic hydroxyl group is particularly advantageous.

The water content of the reaction solution can vary within wide limits. In general, it can be about 20 to 25% by weight.

eingesetzt werden, in der

• Z für ein Element der 5. Hauptgruppe des Periodensystems steht,
• _R ⁴ bis _R ⁷ gleich oder verschieden sind und gegebenenfalls substituiertes Alkyl, Cycloalkyl, Aralkyl oder Aryl bedeuten oder zwei der Reste R⁴ bis R⁷ zusammen mit dem Zentralatom Z und gegebenenfalls weiteren Heteroatomen einen Heterocyclus bilden, wobei die Reste _R ⁴ bis _R ⁷ gemeinsam mindestens 6 Kohlenstoffatome enthalten, und
• A ein unter den Bedingungen des erfindungsgemäßen Verfahrens inertes anorganisches oder organisches Anion bedeutet.

For the process according to the invention, onium salts of the formula

be used in the

• Z represents an element of the 5th main group of the periodic table,
• _R ⁴ to _R ^{7 are} identical or different and represent optionally substituted alkyl, cycloalkyl, aralkyl or aryl or two of the radicals R ⁴ to R ⁷ together with the central atom Z and optionally further heteroatoms form a heterocycle, the radicals _R ⁴ to _R ⁷ together contain at least 6 carbon atoms, and
• A is an inorganic or organic anion which is inert under the conditions of the process according to the invention.

As elements of the 5th main group of the periodic table (according to Mendelejeff) are mentioned: nitrogen, phosphorus, arsenic, antimony or bismuth.

The radicals R ⁴ to R ⁷ can be low-molecular or high-molecular organic radicals.

As low molecular weight organic radicals are optionally substituted alkyl radicals, cycloalkyl radicals, aralkyl radicals or Aryl residues called. Two of the radicals R to R ⁷ can also form a heterocycle together with the central atom Z and optionally further heteroatoms.

The optionally substituted or branched alkyl radicals can be especially those with 1-18 carbon atoms, preferably with 1-12 carbon atoms, such as the methyl, ethyl, isomeric propyl, butyl, octyl, decyl or dodecyl radicals.

The cycloalkyl radicals can be cyclopentyl and in particular cyclohexyl radicals optionally substituted by C ₁ -C ₄ alkyl radicals.

The aralkyl radicals can be benzyl radicals optionally substituted by C ₁ -C ₄ alkyl radicals, methoxy groups or halogen atoms.

The aryl radicals can be phenyl radicals optionally substituted by C ₁ -C ₄ alkyl radicals, methoxy groups, ethoxy groups or halogen atoms.

In the case of a heterocycle, which two adjacent radicals R ⁴ to R ^{7 can form} together with the central atom Z and optionally with further heteroatoms, oxygen, nitrogen or sulfur are preferred as further heteroatoms.

The 5- and 6-membered heterocycles may be mentioned, for example the pyrrolidine ring, the piperidine ring or the morpholine ring.

An example of a polymeric organic radical in one of the retoms R ¹ to R ⁷ is a polystyrene which may have been crosslinked by dinylbenzene.

The total number of carbon atoms of all radicals R ⁴ to R ⁷ is at least six for the process according to the invention. For example, the maximum number of all carbon atoms in a polymeric organic radical can be very large. The preferred total number of carbon atoms of all low-molecular radicals R ⁴ to R ⁷ is 8 to 25.

Preferred anions A are the chloride, bromide and hydroxide anion.

in der

• Z' Stickstoff oder Phosphor bedeutet und
• R⁴ bis R⁷ und A die oben angegebene Bedeutunq haben.

Preferred onium salts for the process according to the invention are quaternary ammonium or phosphonium salts of the formula

in the

• Z 'means nitrogen or phosphorus and
• R ⁴ to R ⁷ and A have the meaning given above.

Examples of the preferred quaternary ammonium or phosphonium salts are: tetraethylammonium chloride, tetrabutyylammonium bromide, triethyl-benzyl-ammonium hydroxide, benzyl-dimethyl-dodecyl-ammonium chloride, dibutyl-piperidinium bromide, methyl-trioctylammonium chloride, phenethyl-ammonidyl chloride, dimethyl-ammonidyl-chloride, dimethyl-ammonidyl-chloride, dimethyl-ammonidyl-chloride, dimethyl-ammonidyl-chloride, dimethyl-ammonidyl-chloride, dimethyl-ammonidyl-chloride, dimethyl-ammonidyl chloride, Benzyl-methyl-piperdinium hydroxide, triethyl-phenyl-ammonium chloride, dodecyl-trimethyl-ammonium hydroxide, cyclohexyl-dodecyl-dimethyl-ammonium chloride, methyl-ethyl-piperidinium bromide, triphenyl-benzyl-phosphonium bromide,. Tetrabutyl phosphonium chloride, tributyl benzyl phosphonium chloride.

Quaternary ammonium compounds in which one of the radicals R to R is a polymeric radical can be, for example, ion exchangers based on styrene and generally 2 mol% of divinylbenzene as crosslinking agents which carry quaternary ammonium groups.

The amounts of the quaternary onium salt used can vary from 1 to 20% by weight and are generally about 5 to 10% by weight, based on the starting compound.

The quaternary onium salts mentioned are known as phase transition catalysts in multiphase systems and can be prepared by known processes (Houben-Weyl, 4th ed. Stuttgart 1958, volume XI, 2, p. 587 and volume XIV, 2nd p. 750).

The process according to the invention can be carried out in the temperature range from about 0 to about 80 ° C., preferably from about 50 to 75 ° C.

The process according to the invention can be explained by the following reaction equation:

in der die Reste R¹, R², R³ und Y die oben angegebene Bedeutung haben und
R¹² ein niederer unverzweigter oder verzweigter Alkylrest ist, isoliert werden.In a particular embodiment of the process according to the invention, intermediates, for example alkoxy compounds of the formula

in which the radicals R ¹ , R ² , R ³ and Y have the meaning given above and
R ^{12 is} a lower unbranched or branched alkyl radical can be isolated.

The alkyl radical R ^{12 of} these alkoxy compounds is determined by the alcohol used as the solvent; when using methanol, a methoxy compound is obtained.

Such alkoxy compounds are known (J. Org. Chem. 26, 2707 (1961)) and can be prepared, for example, by reacting an organically bound halogen atom with sodium methylate or with methanolic potassium hydroxide.

In the process according to the invention, these alkoxy compounds can be isolated if one works in the temperature range from about 15 to 35 ° C.

The alkoxy compounds can be isolated as intermediates in the process according to the invention if one works at low temperatures.

The method according to the invention can be carried out, for example, as follows:

In the reaction vessel, the starting compound, the Lö-. submitted solvent and the catalyst and added the alkali metal hydroxide, for example as an aqueous solution, while stirring. The temperature then rises; the dropping rate is regulated so that the desired reaction temperature is not exceeded. After the end of the addition, stirring is continued for a few hours at the reaction temperature; The phenol is in the form of its alkali salt and can be acidified with a mine in the usual way be obtained. It can now be separated by phase separation (in the case of liquids), by filtering (in the case of solid products), by extraction from the reaction mixture or by steam distillation.

Compared to the known processes for the production of trifluoromethylphenols, the process according to the invention has the advantage of being simple to carry out and leading to the desired phenols in one step.

The quaternary onium salts of the formula (IV) are known as phase transition catalysts in systems with two immiscible liquid phases (DT-OS 2 634 419).

The method according to the invention, however, is carried out with quaternary onium compounds in a system with only one liquid phase.

in der die Reste R¹, R², R3 und y die oben angegebene Bedeutung haben,
hergestellt werden.According to the inventive method, trifluoromethylphenols of the formula

in which the radicals R ¹ , R ² , R3 and y have the meaning given above,
getting produced.

in der

• _R ⁸ Trifluormethyl, Chlor oder Wasserstoff,
• R⁹ Trifluormethyl, Nitro oder Chlor,
• R¹⁰ _Nit_ro, Chlor oder Carboxyl,
• _R ¹¹ _Methoxy oder Wasserstoff

bedeuten,
wobei von den Substituenten R und R⁹ einer eine Trifluormethylgruppe darstellt und von den Substituenten R⁸ und R höchstens einer Wasserstoff ist, sind neu.The trifluoromethylphenols of the formula

in the

• _R ⁸ trifluoromethyl, chlorine or hydrogen,
• R ⁹ trifluoromethyl, nitro or chlorine,
• R ¹⁰ _N it _r o, chlorine or carboxyl,
• _R ¹¹ _M ethoxy or hydrogen

mean,
where one of the substituents R and R ^{9 represents} a trifluoromethyl group and of the substituents R ⁸ and R is at most one hydrogen are new.

• 2-Chlor-4-trifluormethyl-6-nitro-phenol
• 2-Chlor-6-trifluormethyl-4-nitro-phenol
• 4-Chlor-2-trifluormethyl-6-nitro-phenol
• 3-Methoxy-4-trifluormethyl-6-nitro-phenol
• 5-Nitro-3-trifluormethyl-salicylsäure

Examples of compounds of the formula (VII) which may be mentioned are:

• 2-chloro-4-trifluoromethyl-6-nitro-phenol
• 2-chloro-6-trifluoromethyl-4-nitro-phenol
• 4-chloro-2-trifluoromethyl-6-nitro-phenol
• 3-methoxy-4-trifluoromethyl-6-nitro-phenol
• 5-nitro-3-trifluoromethyl salicylic acid

The trifluoromethylphenols, in particular the new trifluoromethylphenols, are intermediate products for the production of crop protection agents, in particular herbicides (DT-OS 2 311 638, DT-OS 1 944 335).

For example, a trifluoromethylphenol of the formula VI can be reacted with p-nitrochlorobenzene in the presence of potassium methylate to give trifluoromethyl nitrodiphenyl ether.

Herbicides from new trifluoromethylphenols of the formula VII show improved activity compared to the known herbicides.

example 1

400 ml of methanol, 20 g of benzyldimethyldodecylammonium chloride and 180 g of 4-chloro-3-nitro-benzotrifluoride are placed in the reaction flask with stirring and then 400 g of 50% sodium hydroxide solution are added dropwise. The temperature rises to approx. 70 ° C if the addition takes place in approx. 20 minutes. The mixture is then stirred for a further 4 hours at 65 ° C., then cooled by throwing in ice and adjusted to pH 3 with concentrated hydrochloric acid. The phenol is driven over with steam and the phases in the receiver are separated by adding about 50 ml of concentrated hydrochloric acid.

There are 156 g of 2-nitro-4-trifluoromethylphenol with a purity of more than 98.5% after gas chromatographic analysis, which corresponds to a yield of 91% of theory.

: 1.5020.Boiling point: 92-95 ⁰ C at 15 mm,

: 1.5020.

Example 2

450 g of 2-chloro-5-nitro-benzotrifluoride are placed in 1250 ml of methanol and 35 g of tetraethylammonium chloride. Then 1000 q of an aqueous, 50% iq. Potassium hydroxide solution are added dropwise (1 hour), the temperature being kept at 40 ° C. by cooling. About 30 minutes after the end of the addition, the mixture is heated to 80 ° C. for 6 hours, cooled and acidified with concentrated hydrochloric acid. The mixture is extracted several times with 300 ml of methyl chloride, the organic phase is dried with sodium sulfate and under freed from the solvent under reduced pressure. Approximately 413 g of crude product are obtained, F: 90-95 ⁰ C with a purity of about 95% according to gas chromatographic analysis. After recrystallization from toluene or distillation at 0.5 mm, pure 4-nitro-2-trifluoromethylphenol is obtained, F: 134 ° C.

Example 3

50 g of 3,4-dichloro-5-nitro-benzotrifluoride and 5 g of benzyltriethylammonium bromide are placed in 150 ml of methanol, and 100 g of 50% strength sodium hydroxide solution are added dropwise at 25 to 30 ° C. The mixture is then stirred for a further 4 hours at 65 ° C., cooled, mixed with 100 ml of water and acidified with sulfuric acid. The crude product is extracted with methylene chloride, the solution is dried and the methylene chloride is distilled off. The residue is fractionally distilled, and 35 g of 2-chloro-4-trifluoromethyl-6-nitrophenol are obtained with a boiling point of 74 to 76 ° C at 0.25 mm.

F: 33-34 ⁰ C from hexane. Yield: 77% of theory.

Example 4

50 g of 2,3-dichloro-5-nitro-benzotrifluoride in 150 ml of methanol and 5 g of tetrabutylammonium chloride are placed in the reaction vessel, and 100 g of 50% strength sodium hydroxide solution are then added dropwise in such a way that the temperature rises to a maximum of 50 ° C. At this temperature, the mixture is stirred for 5 hours, then cooled and acidified with hydrochloric acid. The product is taken up in methylene chloride and, after drying, distilled with sodium sulfate. At K _p0.1 : 33 g of 2-chloro-6-trifluoromethyl-4-nitrophenol, which has a melting point of 78 to 80 ° C., pass from 110 to 115 ° C.

Yield: 73% of theory.

Example 5

104 g of 2,4-dichloro-5-nitrobenzotrifluoride and 7 g of tetrabutylphosphonium chloride are placed in 400 ml of methanol and 400 g of 50% sodium hydroxide solution are added dropwise. The temperature is kept at a maximum of 70 ° C. and, after the dropping has ended, stirring is continued for 6 hours. The cooled mixture is acidified with hydrochloric acid, then the product is extracted with methylene chloride. After the solvent has been distilled off, the residue is recrystallized from isopropanol. This gives 69 g of 3-methoxy-4-trifluoromethyl-6-nitrophenol with a melting point of 77 to 78 ° C, the yield is 73% of theory.

Example 6

45 g of 4-chloro-3-nitro-benzotrifluoride and 10 ml of a 50% strength aqueous benzyldodecyldimethylammonium chloride are placed in 150 ml of xthylene glycol monomethyl ether and 100 g of 50% strength potassium hydroxide solution are added dropwise in about 30 minutes to a temperature of 65 ° C. The mixture is then stirred at 65 ° C. for 6 hours, then cooled, acidified with concentrated hydrochloric acid and about 500 ml of distillate are driven over with steam. The organic phase is separated off, washed with 20 ml of dilute hydrochloric acid, separated off again and dried with sodium sulfate. 38 g are obtained 2-nitro-4-trifluoromethylphenol, which corresponds to 92% of theory.

Example 7

If example 6 is repeated and 150 ml of ethanol are used instead of ethylene glycol monomethyl ether, 39 g of 2-nitro-4-trifluoromethylphenol are obtained, which corresponds to 94% of theory.

Example 8

27 g of 6-chloro-3-nitro-5-trifluoromethylbenzoic acid are dissolved in 100 ml of methanol, 1 g of trioctyl-methyl-ammonium chloride is added, and 70 g of 50% sodium hydroxide solution are then added dropwise with stirring, the temperature not exceeding 65.degree should rise. After stirring for a further 4 hours at 65 ° C, cool and add enough water until everything has dissolved. The mixture is then acidified by dropping concentrated hydrochloric acid at 20 to 30 ° C., whereupon the product precipitates and is suctioned off. The crude 5-nitro-3-trifluoromethyl-salicylic acid is recrystallized from toluene, melting point: 171-173 ° C., yield: 18 g; that corresponds to 72% of theory.

Example 9

2-7 g of 2-chloro-3-nitro-5-trifluoromethylbenzoic acid and 1 g of tetraethylammonium chloride are placed in 200 ml of methanol and 70 g of 50% sodium hydroxide solution are added dropwise with stirring. The mixture is stirred for 5 hours at 65 ° C, diluted with 300 ml of H ₂ 0 and then made acidic with hydrochloric acid. The solid product is suctioned off and from water recrystallized. 16 g of 2-hydroxy-3-nitro-5-trifluoromethyl-benzoic acid with a melting point of 166 to 168 ° C. are obtained.

Example 10

: 1.5003.45 g of 4-chloro-3-nitro-benzotrifluoride are initially dissolved in 150 ml of methanol. Then 80 g of ion exchange resin with quaternary ammonium groups are added, the mixture is stirred for 10 minutes, 100 g of 50% sodium hydroxide solution are added dropwise to a maximum temperature of 70 ° C. and the mixture is stirred at 65 ° C. for 8 hours. After the mixture has cooled, it is acidified with concentrated hydrochloric acid, filtered off from the ion exchanger and the crude product is distilled with steam. 27 g of 2-nitro _- 4-trifluoromethylphenol are obtained.

: 1,5003.

Example 11

A) 45 g of sodium hydroxide and 10 g of tetraethylammonium chloride are placed in 200 g of methanol and 112.5 g of 2-chloro-5-nitro-benzotrifluoride are added dropwise at 25 to 30 ° C., followed by stirring at 30 ° C. for 5 hours . Then the mixture is poured into 250 ml of water and extracted with methylene chloride. After evaporation of the solvent, the compound is recrystallized from isopropanol. 67 g of 2-methoxy-5-nitrobenzotrifluoride with a melting point of 70 to 74 ° C. are obtained.

_B ) 67 g of 2-methoxy-5-nitro-benzotrifluoride are dissolved in 150 ml of methanol, first 8 g of tetraethylammonium chloride added and then 150 g of 50% potassium hydroxide solution added dropwise to a temperature of 70 ° C. The mixture is stirred at 70 ° C for 8 hours, cooled, acidified and extracted with methylene chloride. After evaporation of the methylene chloride, 52 g of crude 4-nitro-2-trifluoromethylphenol remain, F: 90 to 94 ° C, which can be purified by distillation.

Claims (12)

1) Process for the preparation of trifluoromethylphenols, characterized in that compounds of the formula

in the X halogen, R ¹ , R ² and _R ^{3 are} hydrogen, trifluoromethyl or a substituent that promotes the exchange of X for a hydroxyl group, and Y is hydrogen, a halogen or alkoxy
mean,
where at least one of the substituents R ¹ , R ² and R ^{3 is} a trifluoromethyl group and at least one is a substituent which favors the exchange of the radical X for a hydroxyl group,
in alcoholic solution with excess aqueous alkali hydroxide in the presence of quaternary onium salts. 2) Process according to claim 1, characterized in that in the presence of a quaternary onium salt of the formula

in the Z is an atom of the fifth main group of the periodic table _R ⁴ to R ⁷ independently of one another are optionally substituted alkyl, cycloalkyl, aralkyl or aryl or two of the radicals R ⁴ to R ⁷ together with the central atom Z and optionally further heteroatoms form a heterocycle, the radicals R ⁴ to R ⁷ together at least 6 Contain carbon atoms, and A represents a chloride, bromide or hydroxide anion;
is working. 3) Process according to claim 1 and 2, characterized in that the quaternary onium salt is a quaternary ammonium or phosphonium salt, the substituents of which contain a total of 8 to 25 carbon atoms. 4) Process according to claim 1 and 2, characterized in that an ion exchanger based on styrene with 2 mol% divinylbenzene as the crosslinking agent containing quaternary ammonium groups is used as the quaternary ammonium salt. 5) Method according to claim 1 to 4, characterized in that the quaternary onium salt is used in an amount of 1 to 20 wt .-%, based on the halobenzotrifluoride. 6) Method according to claim 1 to 5, characterized in that the quaternary onium salt is used in an amount of 5 to 10 wt .-%, based on the halobenzotrifluoride. 7) Method according to claim 1 to 6, characterized in that alcohols are used as the alcoholic solvent with a lower unbranched or branched alkyl radical. 8) Process according to claim 1 to 7, characterized in that the alkali metal hydroxide is used in a triple molar amount, based on the halobenzotrifluoride. 9) Process according to claim 1 to 8, characterized in that sodium hydroxide or potassium hydroxide is used as the alkali hydroxide. 10) Process according to claim 1 to 9, characterized in that one carries out the reaction in the temperature range from 0 to 80 ° C. 11) Process according to claim 1 to 10, characterized in that compounds of the formula

in the R ¹ , _R ² and _R ^{3 are} hydrogen, trifluoromethyl or a second-order substituent in the sense of the substituents on aromatic compounds, y is hydrogen, a halogen atom or alkoxy and R ^{12 is} a lower unbranched or branched alkyl radical
means
starts. 12) Trifluoromethylphenols of the formula

in the _R ⁸ trifluoromethyl, chlorine or hydrogen, _R ⁹ trifluoromethyl, nitro or chlorine, R ¹⁰ nitro, chlorine or carboxyl, R ¹¹ methoxy or hydrogen
mean,
wherein one of the substituents _R ⁸ and R ^{9 represents} a trifluoromethyl group and of the substituents R ⁸ and R ^{11 is} at most one hydrogen.