DE1158490B - Process for the production of fluorine-containing acetoacetic acid chlorides or their solutions - Google Patents

Description

It is known that di- and trichloroacetic acid chloride with ketene to give the corresponding acetoacetic acid chlorides implement (reports of the German Chemical Society, vol. 47 [1914], p. 40).

The investigations have shown that when conventional solvents are used, in spite of a multiple excess of ketene, the conversion and yield are unsatisfactory and that the reaction of the ketene with the acid chloride only proceeds approximately satisfactorily when liquid sulfur dioxide is used as the solvent. The yields in this reaction are between 37 ¹⁰ Zo for dichloroacetyl chloride and 63% for trichloroacetyl chloride (Collection of Czechoslovak Chemical Communications, Vol. 20 [1955], pp. 285 to 289).

A process has also already been described which allows dichloroacetyl chloride and trichloroacetyl chloride with ketene in solvents other than sulfur dioxide, e.g. B. in methylene chloride, chloroform, Ethyl acetate to carry out, in some cases, good yields if catalysts are used (German interpretation document 1 041 030).

Up to now, however, it has not been possible to isolate the chlorinated acetoacetic acid chlorides obtained. Rather, these acid chlorides first had to be esterified in their solutions and then the yields of acid chloride can be determined from the yield of ester.

A process for the preparation of fluorine-containing acetoacetic acid chlorides or their solutions has now been established found, which is characterized in that the corresponding fluorine-containing acetyl chlorides with ketene in the absence of catalysts at temperatures between -50 and + 60 ° C, preferably between -30 and + 5 ° C, optionally in the presence of organic solvents and the reaction products obtained, if desired separated by processes known per se, in particular by distillation. In contrast to the Acetyl chlorides, in which the hydrogen atoms in the methyl group are partially or completely replaced by chlorine atoms is replaced, so those acetyl chlorides in which at least one hydrogen atom of the methyl group is replaced with fluorine atoms easily and with good yield without using react a catalyst with ketene to form the corresponding acetoacetic acid chlorides.

The usual catalysts in ketene chemistry, such as uranyl nitrate, boron trifluoride, aluminum chloride or ferric chloride, have no effect on the reaction. The use of solvents is not necessary, but beneficial. As such, let process of manufacture

of fluorine-containing acetoacetic acid chlorides

or their solutions

Applicant:

Farbwerke Hoechst Aktiengesellschaft
formerly Master Lucius & Brüning,
Frankfurt / M.

Dr. Otto Scherer, Bad Soden (Taunus),
Dr. Heinrich Kühn, Frankfurt / M.-Schwanheim,

Dr. Franz Lömker, Hofheim (Taunus),

and Dr. Rudolf Heinrich, Kelkheim-Homau,

have been named as inventors

z. B. methylene chloride, chloroform, carbon tetrachloride, difluorodichloromethane, difluorodibromomethane, Butane, pentane and other aliphatic, optionally partially or wholly halogenated Hydrocarbons, benzene, toluene, chlorobenzene, dichlorobenzene and other aromatic hydrocarbons, Methyl acetate, ethyl acetate or propionic acid ester or ethers, such as diethyl ether or tetrahydrofuran. The choice of solvent is not important for the course of the reaction decisive and can be made dependent on the way in which the reaction product is used should be processed further. The amount of solvent is also not critical. You can generally 0.1 to 20 parts to 1 part of acid chloride, preferably 0.5 to 5 parts, be.

The reaction between ketene and the fluorine-containing acetyl chloride is carried out at temperatures between -50 and + 60 ° C, preferably between -30 and + 5 ° C. One proceeds in general so that one in the liquefied fluorine-containing acetyl chloride or its solution ketene, expedient below the surface of the liquid phase, introduces and maintains the desired temperature by cooling receives. In order to achieve good sales, it is advantageous to have a certain excess of ketene, for example 0.5 to 1.0 moles per mole of acetyl chloride used. Also larger surpluses are possible. About the escape of kets

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To avoid it, it is advisable to equip the reaction vessel within 2 hours with 210 g of ketene (5 mol) under a reflux condenser which is kept stirring at a temperature of -30 ° C, which is below the boiling point . This is due to the heat of reaction released by the ketene (-56 ° C). However, if one wishes to avoid such a vaporized difluorochloromethane by means of strong cooling, one can of course condense a reflux condenser. Towards the end of the reaction also work under excess pressure, which, however, was due to the fact that the temperature in the mixture was about the tendency of the ketene to polymerize upwards of -22 ° C. The mixture was stirred at this temperature. For example, overprinting temperature can be applied for a few more minutes and distilled from 1 to 5 at. Also remove the working solvent under atmospheric pressure. This at pressures below atmospheric pressure is possible to a certain extent until the residue has been distilled under reduced pressure to a certain extent, provided that one lacks. 510 g = 770/0 of the theory using trifluoro-sufficiently low temperatures were obtained. acetoacetyl chloride with a boiling point of +8 ⁰ C

After the reaction has ended, it is expediently 5.8 torr.

process that initially the unreacted acid chloride solidified at about -35 ° C

Starting material distilled off. Then one can develop a colorless crystal mass. At atmospheric pressure neither the fluorine-containing acetoacetic acid chloride formed could not be distilled without decomposition. It is Esterify in a known manner in its solution and at room temperature for some time and stable then the ester can be separated off in a known manner at lower temperatures for a long time. But you can also keep the solution set first. There are those for an acidic agent distill off if this boils lower than the typical chloride reaction products such. B. Esters, Acetoacetyl chloride formed and then the reaction amides and ketones according to Friedel-Crafts, distill the product yourself. In this way, analysis

the previously unknown trifluoroacetoacetyl chloride pure _Ώ , # - -> - r * χι -ι <■> -c ι-, τ / -ι

be won. Since the resistance of the one in question is calculated .... L- 27.6, M 1.2, J- 32.7, Cl 20.0%;

coming acetoacetic acid chlorides with increasing 25 found C 27.5, H 1.7, F 32.4, Cl 19.6%,

If the temperature decreases, it is advantageous to use the distilla- 27.8, 1.5, 32.4, 19.6%.

tion of these compounds at the lowest possible temperature, ie with the best possible vacuum. It can be advantageous, as described in Example 1, to use 500 g of solvent which has a higher boiling point than the acid chloride formed with 210 g of ketene in 400 g of trifluoroacetyl chloride. Methylene chloride at -5 to +5 ⁰ C within 3 hours. The fluorine-containing acetoacetic acid thus obtained is reacted. The product chlorides can now be worked up as such or in their solutions as described above. Yield = 500 g further to esters, anilides and others, for (75% of theory). Dye chemistry, pharmaceutical chemistry or 35. Compounds of Interest in Plant Protection Chemistry Example 5

implemented. As described in Example 1, 500 g

After it was known that the chlorinated trifluoroacetyl chloride with 210 g of ketene in 400 g of acetoacetic acid chlorides can only ^{be obtained in such yields using methylene chloride at -5 to +5 0} C within catalysts, reacted for 4-2 hours. For work-up, the industrial production appears profitable, reaction product with 200 g of absolute ethanol at it was very surprising that the analogous fluorine-0 ° C esterified. 585 g = 84.0% of the compounds contained were obtained, not only without the use of theory . ,.

effective catalysts for the fluorine-containing examples

bindings are practically ineffective. Since it was, as described in Example 1, 429 g

Process according to the invention also provides access to difluorochloroacetyl chloride with 180 g of ketene in 500 g to a group of interesting, mostly difluorodichloromethane at -25 to -30 ° C within opens previously unknown compounds, it takes 50 of 4V2 hours implemented. After removing the also a significant technical advance. Solvent was the reaction product with

Examples 1 to 5 below show the 180 g of absolute ethanol esterified in the cold. The conversion of fluoroacetyl chlorides and ketene without yield was 425 g = 73.0 Vo of the theory of di-catalysts according to the invention. Following ethyl fluorochloroacetoacetate from the boiling point, comparative experiments are shown in which trifluoroacetyl chloride with ketene in the presence of 55 70 to 72 ° C. at 22 to 24 mm Hg.

of catalysts customary for ketene reactions - Example 5

is set, without better yields than there were, as described in Example 1, 248 g

catalyst-free work can be achieved. This ver fluorodichloroacetyl chloride with 126 g of ketene in 500 g Searches show that the reaction with chlorodichloromethane intervened at -25 to -30 ° C Acetyl chlorides catalytically active half of 3V2 hours. After removal bonds: uranyl nitrate, iron (III) chloride, boron trioxide was the reaction product with the solvent fluoride, not esterified as 200 g of absolute ethanol in the cold for the process according to the invention. By Catalysts are to be considered. Distillation were 55 g of fluorodichloroacetic acid

t> · · 1 .j 65 ethyl ester (corresponding to 52 g unreacted

⁶¹⁵ P ¹ acid chloride) and 185 g fluorodichloroacetoacetic acid

In a solution of 500 g of trifluoroacetyl chloride ethyl ester boiling point 86 to 87 ° C at 15 Torr (3.8 moles) in 400 g of difluorodichloromethane were obtained. This corresponds to a conversion of 79 ° / o

and a yield of 76% based on the converted acid chloride.

As evidence for the by the invention Process achievable technical progress, the following comparative tests were carried out:

a) As described in Example 1, 500 g of trifluoroacetyl chloride with 210 g of ketene in 500 g of difluorodichloromethane, but in the presence of 5 g uranyl nitrate, at -25 to -35 ° C within 3 hours implemented. After removal of the solvent, the reaction product with 220 g of absolute Ethanol esterified in the cold. There were 532 g = 76.2% of theory of ethyl trifluoroacetoacetate obtained from boiling point 130 to 131.5 ° C. This yield corresponds to the yield for the catalyst-free one Work according to example 1.

b) As described in Example 1, 500 g of trifluoroacetyl chloride were reacted with 210 g of ketene in 500 g of difluorodichloromethane, but in the presence of 15 g of iron (III) chloride at -25 to -3O ⁰ C within 3½ hours. The product was worked up as described in Example 1. Yield = 470 g of trifluoroacetoacetyl chloride (71% of theory).

c were) as described in Example 1, is reacted with trifluoroacetyl chloride 500 g 210 g 500 g ketene in difluorodichloromethane, but in the presence of 6 cc of a saturated solution of boron trifluoride in tetrahydrofuran within 3Va hours at -25 to -30 ⁰ C. The product was worked up as described in Example 1; g of trifluoroacetoacetyl chloride = 74% of theory, that is to say practically the same yield as in Example 1, was obtained.

Claims (3)

Patent claims: 1. A process for the preparation of fluorine-containing acetoacetic acid chlorides or their solutions, characterized in that the corresponding fluorine-containing acetyl chlorides with ketene in the absence of catalysts at temperatures between -50 and + 60 ° C, preferably between -30 and + 5 ° C, optionally in the presence of organic solvents, and the reaction products obtained are, if desired, separated off by processes known per se, in particular by distillation. 2. The method according to claim 1, characterized in that one is perfluorinated or with Fluorine and chlorine reacts perhalogenated acetyl chlorides with ketene. 3. Process according to Claims 1 and 2, characterized in that the reaction is below an overpressure of 1 to 5 at. is carried out. Considered publications:
German Auslegeschrift No. 1041030;
Chemicke Listy, Vol. 49 (1955), pp. 73 to 77. © 309 767/407 11.