JPH04506356A - Method for producing fluorobenzene and fluorotoluene - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Method for producing fluorobenzene and fluorotoluene The present invention provides a method for producing fluorobenzene and fluorotoluene. from lobenzaldehyde to optionally substituted fluorobenzene and/or or optionally substituted fluorotoluenes. case Fluorobenzenes and fluorotoluenes, which may be substituted by It is an important intermediate in the production of products.

Traditionally, fluorobenzene was prepared from the corresponding optionally substituted aniline. It was prepared by azotization and subsequent substitution of the diazo group with fluorine. Sunawa First, diazotization of aniline hydrochloride, and the resulting tetraphthalate of benzenediazonium chloride. Synthesis of fluorobenzene by conversion to fluoroborate followed by heating is It has been known for a long time [Bulb (G, Ba1z) and Zman (G, Schiema music) (Ber, 60 (1927) 1186.1 188); Paper by Flood (D., T., Flood.

Org, 5ynth, Co11. Vol. II (1943) 295 (see). 1,3-difluorobenzene can be converted to benzene-1,3-bisdia in a similar manner. I as starting compound by heating zonium tetrafluoroborate -obtained in a yield of 31% with respect to phenylene diamine (Ziemann (G, Schiemann) and Pillarsky (R, Pillarsky) Paper (Ber, 62 [1929) 3035-3043. Especially 3039) reference〕. Ammonium fluoride or tertiary amine or dimethyl sulfoxide The diazotization of 3-fluoroaniline in anhydrous hydrogen fluoride in the presence of Similarly, 1,3-difluorobenzene was obtained. Yields are reported as 46-73%. (see U.S. Pat. Nos. 4.075.252 and 4.096.196) (See),.

Also when producing 1,4-difluorobenzene from p-phenylenediamine, Similarly low yields (27 to 40%) were obtained for valve (G, Ba1z) and viral. It has been obtained by R. Pillarsky (cited above).

Substituted benzenediazonium hexafluorophos instead of tetrafluoroborate Thermal decomposition of phenates often results in higher oxidation of the corresponding fluorobenzene. However, the yields were still economically unsatisfactory. (K, G, Rutherford et at, J, Org, CheIL26 (1961) 5149-5152)Q Light].

Fluorine toluene is obtained from the corresponding C-methyl substituted aniline in an analogous manner. .

Decarbonylation of aromatic aldehydes over catalysts containing platinum group metals Written by J. Smolik and M. Kraus. (Cal feet.

Czech, Chem, Commun, 37 (1972) 3042-3 051).

Catalytic decarbonylation of the corresponding fluorobenzaldehydes over zeolite catalysts It was also proposed to produce fluorobenzene by chemical reaction (German patent application No. 3). 824141, No. 2). Fluorotoluene from fluorobenzaldehyde can be produced starting from fluoromethylbenzaldehyde using this method. Only then is it possible.

With the present invention, fluorobenzene can now be selectively used from fluorobenzaldehyde. or fluorotoluene.

The subject of the present invention is the general formula (I[) (see claim 1) (in the above formula, RJ2 and and R1 are each independently hydrogen, fluorine, chlorine and/or C,-CS-a fluorine, in which at least one of these radicals is fluorine; In this case, Sl and S2 are independently linked to aromatic nuclei such as hydrogen and/or chlorine. (but preferably hydrogen) Zualdehyde is listed as one of the subgroups of the Mayer/Mendeleev periodic table. on a catalyst made of at least one transition metal and activated by treatment with hydrogen. By reacting at 150 to 600°C, formula (K) (See Section 1) (In the above formula, X represents H or a methyl group, and R', R'', R'', S' and S! have the above meanings). It's a method. If the reaction does not use a carrier gas or the compounds involved in the reaction as opposed to when carried out with a carrier gas that is inert under the reaction conditions. is decarbonylated inter alia to the corresponding fluorobenzene, while If hydrogen is used as carrier gas, especially the corresponding fluorocarbon Hydrogenation to luene takes place. Producing fluorotoluene from fluorobenzaldehyde In order to produce hydrogen, the presence of hydrogen is required.

Catalysts suitable for the process according to the invention contain one or more elements of subgroups 1 to 2. elements such as manganese, rhenium, iron, cobalt, nickel, ruthenium, and um, palladium, osmium, iridium or platinum, preferably platinum and Contains cobalt and/or platinum and rhenium. They are A 1.0. , applied to a carrier such as silica gel or activated carbon. Impregnation, io The elements of group Ⅰ to WNg are dosed by carbon exchange or other conventional methods. All the usual zeolites are also used. used according to the invention The catalysts are preferably used in the form of molded or extrudates. Fluidized bed catalysts can also be used. Used vine.

The method according to the invention is preferably carried out at a temperature of 180 to 440°C. It will be done.

It can be carried out in the liquid phase as well as preferably in the gas phase. Gas phase reaction odor Carrier gases such as nitrogen or Ca6, inter alia, fluorotoluene Hydrogen may also be mixed in if the production of hydrogen is intended.

The total pressure is generally between 0.1 and 100 bar, preferably between 1 and 20 bar. Ru.

However, particular preference is given to using starting materials at atmospheric pressure or in gaseous form. For example, it is operated at counterpressure resulting from being fed through a fixed catalyst.

Catalyst loading (unit weight of starting material per unit weight of catalyst per hour - dimension) h”’-=WHSV=Weight-Hourly-Space-Vel ocity) is preferably 0.1 to 10h-1.

The gas mixture leaving the reaction zone is cooled using conventional material separation methods, e.g. fractional condensation. It can be purified by cooling. However, preferably the desired reaction product is distilled obtained in pure form by

In the following examples, U is the conversion rate and 5ore is 1,3-difluorobenzene. and 5OFT means the selectivity of 2,4-difluorotoluene. .

Example Examples 1) to 5) Tubular reactor with a diameter of 30 mm and a length of 60011 m 0.5% by weight of platinum and about 0.3% by weight of rhenium as carriers. 34 g (50 ml) of commercially available catalyst contained on aluminum was charged. heated Hydrogen (25 A/h) and 2,4-difluorobenzaldehyde ( 14n+l/h). The reaction product is cooled and the condensed fraction is subjected to gas chromatography. Analyzed by matography. The following results were obtained: Example T/”CIJ/% 5oys 5ortExample 6) In the apparatus described in Example 1 The catalyst described therein was treated with hydrogen at 350°C for 3 hours; Then the test of Example 1 was repeated at 440°C using the same amount of nitrogen instead of hydrogen. I returned it. At a conversion rate of 50%, virtually all 1,3-difluorocarbons was produced (SDFI = 99%).

Examples 7) to 9) Instead of the catalysts used in Examples 1 to 6, Using a catalyst containing about 0.5% by weight of palladium on SiO□, and other The following results were obtained by operating according to Examples 1 to 5: Example T/”CU/% S　ov　s　So　FtExample 10) Diameter of 20mm and length of 600mm 50% by weight of finely powdered cobalt and γ-AbO* by extruding 50% by weight to form an extrudate of diameter 2III11. The prepared catalyst was loaded and treated with hydrogen for 3 hours at 300°C. Ta. Nitrogen as carrier gas at 400 °C and 0.5 h-' WHSV When using (151/h), 2,4-difluorobenzaldehyde At 45% conversion of 1,3-difluorobenzene, traces of 2,4-difluorobenzene It was obtained with a selectivity of 99% together with fluorotoluene.

Examples 11) to 14) Using hydrogen instead of nitrogen as carrier gas (151 /h) By repeating the test described in Example 10, the following values were obtained: Example T /”CU/% S□s 5D11+3 350 25 18 80 +4 460 28 23 68 Examples 15) to 17) Tubular reactor I as described in Example 1O containing 1% by weight of rhodium 20ml of extruded rhodium-zeolite catalyst was charged. This catalyst is , Zeolite H-ZSM 5 (SiOt/Al202=90) Color RhC15- Ion exchange using XHtO (38% Rh) and then drying at 110 °C. , calcination at 350°C and subsequent treatment with hydrogen for 3 hours at 350°C. It was manufactured by Next, 2,4-nofluorobenza The aldehyde was introduced into the reactor at a rate of 10 ml per hour in a hydrogen stream of 1Sl.

The following results were obtained: Example T/”Ctj/% 5ots 5OFT+6 420 94 94 6 1744θ 94 55 5 Examples 18) to 20) Instead of the catalyst used in Examples 15 to 17, γ- Using a catalyst containing 2.5% by weight rhodium on Altos and other The procedure was carried out in the same manner as in Examples 15 to 17, and the following results were obtained: Example T/”CU/% S,, SO,? 2 in a nitrogen stream at 370°C. ．． 1,3-difluorobenzene during the reaction of 4-difluoro-benzaldehyde can be obtained selectively.

Examples 22) to 25) Platinum-zeolide catalyst 2 was added to the tubular reactor described in Example 10. 0ml was filled. This catalyst is made of zeolite H-ZSM 5 (Si02/AIt Tetramine platinum(II) chloride in 300 ml of water from 100 g of oz”90) 1 ．． Impregnated with 65g of solution, then dried at 110°C and at 350"C. Calcined for 4 hours and subsequently treated with water at 350° C. for 3 hours. Therefore, it was manufactured. Next, 2,4-difluorobenzene 1 was introduced into the reactor at a rate of 10 II 11 per hour in a stream of 151 hydrogen. At that time, the following The results were obtained; Example T/”CU/% 5ors SDF?Example 26) Diameter of 50M and 600 Rhodium 51i amount % on activated carbon as a support in a tubular reactor with a length of mm 20 ml of granular catalyst containing . 2.4-difluorobenzaldehye 151 at 165℃! into the reactor at a rate of 15 ml per hour in a nitrogen stream of Ta. In this case, 1,3-difluoro-benzene was converted to 99% at 40% conversion. obtained with selectivity.

Examples 27) to 29) Platinum contained therein in the tubular reactor described in Example 1. Rhenium catalyst 20a+1 was metered in. Then 2-chloro-6-fluoro-benzaa The aldehyde was introduced into the reactor at a rate of 10 o+1 per hour in a stream of 157 hydrogen. the In this case, the following results were obtained for Scrm = 1-chloro-3-fluoro-benzene. The selection rate SeF? = Selection for 2-chloro-6-fluoro-toluene Selectivity Example 30) Oxidation as a carrier in a test device as described in Example 1 When using a catalyst containing about st% nickel on aluminum, 47 WHSV of 0,78 h-' and 15I at a temperature of 0 °C! /h of hydrogen-ca It was destroyed in the rear gas flow.

Copy and translation of written amendment) Submission form (Article 184-8 of the Patent Act) April 23, 1992

Claims (7)

[Claims] 1. Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the above formula, X represents H or a methyl group. and R1, R2 and R3 independently of each other represent at least one group H, F, Cl or and C1-C3-alkyl, at least one of these radicals being fluorine, and S1 and S2 independently of each other are H and/or benzene. a group that reduces the electron density of the electron nucleus, preferably H) In the method for producing toluene and fluorotoluene, formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the above formula, R1, R2, R3, S1 and S2 have the above meanings) in the periodic system V. consisting of at least one transition metal of subgroups II to VIII and treated with hydrogen The reaction can be carried out at 150 to 600°C over an activated catalyst. The method for producing fluorobenzene and fluorotoluene as described above, characterized by: 2. characterized in that the catalyst contains cobalt, platinum and/or platinum-rhenium A method according to claim 1. 3. Claim 1 or 2, characterized in that the reaction is carried out in a gas phase. How to read. 4. Claims characterized in that it operates at temperatures between 180 and 440°C. A method according to any one of Items 1 to 3. 5. At a total pressure of 0.1 to 100 bar, preferably 1 to 20 bar, Preferably atmospheric pressure or a back pressure created by the supply of gaseous starting material through the catalyst system. 5. A method according to claim 3 or 4, characterized in that the method is operated at. 6. Fluorotoluene of formula I (see claim 1), where X=methyl of fluorobenzaldehyde of formula II (see claim 1) to prepare Claims 1 to 5, characterized in that the reaction is carried out in the presence of hydrogen. Either method. 7. Fluorobenzene of formula I (see claim 1) where X=H is produced of fluorobenzaldehyde of formula II (see claim 1) to produce The reaction is carried out under reaction conditions such as nitrogen, which is inert to the compounds involved in the reaction. in the presence of at least one gas and preferably also in the absence of hydrogen 6. A method according to any one of claims 1 to 5, characterized in that it is carried out.