DE1618181A1 - Process for the production of carboxylic acid chlorides - Google Patents

Description

Process for the preparation of carboxylic acid chlorides It is known Carboxylic acid chlorides by reaction of phosgene with carboxylic acids (US patent 3 184 506, German patent specification 283 896) or their salts (Chemical Reyiews, Volume 4 (1927), pages 155 and 156; German patents 29 669, 284 617). Of carboxylic anhydrides is from Houben, Weyl, methods of organic chemistry, Volume 8, pages 469 ff. Known that they compared to inorganic acid halides are stable under normal conditions; in special cases it is implemented to the acid chlorides only at higher temperatures (phthalic anhydride with phosphorus pentachloride. ~), if necessary in the presence of zinc chloride catalysts (succinic an-.t ~; ~ .t --.... r: ~ :: .... ~. ~. ~. hydride with thionyl chloride) instead. It is true that Chemical Reviews suspected that in the implementation of the carboxylic acid chloride the corresponding Anhydride occurs as an intermediate, German patents 283 896 and 284 617 but refute this assumption and show that only after conversion to the carboxylic acid chloride this can form the anhydride in a further stage It was It has now been found that carboxylic acid chlorides are advantageously obtained by using carboxylic acid anhydrides with phosgene at a temperature between 20 and 15Q ° C.

Compared to the aforementioned method, the method delivers the invention in a simpler way a large number of carboxylic acid chlorides in part better yield and purity without significant evolution of chlorine hydrogen. With regard to These results were relatively mild on the aforementioned publications Reaction conditions surprising.

The starting materials used are carboxylic acid anhydrides with or several, preferably one or two, anhydride groups. Aliphatic, cycloaliphatic, araliphatic or aromatic anhydrides, preferably with up to 14 each Carbon atoms, are used; pie can still go through under the reaction conditions inert groups or atoms, e.g. B. halogen, may be substituted. With unsaturated anhydrides the method proves to be particularly advantageous because this, for. B. in comparison for reaction with phosphorus pentachloride, do not polymerize under the process conditions. The carboxylic anhydride can optionally also be mixed with the corresponding Carboxylic acid or its carboxylic acid chloride are implemented.

So kinnen z. B. used the following carboxylic acid anhydrides as starting materials acetic acid, phenylacetic acid, o-toluic acid, M-naphthoic acid, cyclohexanecarboxylic acid, Phthalic acid, dichloromaleic acid, glutaric acid, allyl succinic acid, ß-crotyl succinic acid -, 2-ethylhexanecarboxylic acid, succinic acid, hexahydrobenzoic acid, dichloroacrylic anhydride.

Phosgene is used in a stoichiometric amount or preferably in excess, in particular used in up to a 2-fold excess over the stoichiometric amount. The reaction is carried out at a temperature between 20 and 150 ° C, preferably between 50 and 120 ° C without pressure or under pressure, carried out continuously or discontinuously. It is advisable to use catalysts in the form of on the nitrogen atom in the reaction substituted carboxamides or lactams or tertiary amines, e.g. B.

Dimethylformamide, N-methylpyrrolidone, dimethylaniline, triethylamine ; they are generally used in an amount of 0.1 to 20, preferably 0.5 to 2% by weight, based on the amount by weight of anhydride, fed to the reaction. One can organic solvents which are inert during the reaction under the reaction conditions, such as aromatic hydrocarbons, e.g. B. benzene, toluene, xylene; Chlorinated hydrocarbons, z. B. chloroform, carbon tetrachloride; Ether, e.g. B. dioxane, diethyl ether; Petroleum ether ; use.

The reaction can be carried out as follows: In the starting material, optionally together with catalyst and / or solvent, is used in the case of the aforementioned Temperature for 1/2 to 5 hours. initiated the phosgene. As a reaction vessel All systems with a good mixing device, such as stirred kettles and in particular, can be used Circulators or bubble columns can be used. Then from the reaction mixture the end product is separated off in the usual way, e.g. by fractional distillation. the Carbonic acid chlorides produced in this way are particularly pure and can directly, e.g. B. processed further by hydrogenation according to Rosenmund to the aldehyde will.

The compounds preparable by the process of the invention are valuable starting materials for the production of solvents, pharmaceuticals and Dyes.

The parts given in the examples are parts by weight.

Example 1 114 parts of gluten anhydride are heated to 80.degree and mixed with 2 parts of dimethylformamide. One conducts at a constant temperature with stirring, add 120 parts of phosgene to the mixture over the course of 1.5 hours then fractionates the reaction mixture in vacuo. At 1 Torr go in the boiling range from 83 to 85 ° C 159 parts of glutaryl chloride, corresponding to a yield of 94% of theory.

Example 2 /.

169 parts of glutaryl chloride, 2 parts of dimethylformamide and 114 parts Glutaric anhydride are mixed and heated to 80 ° C. At this temperature 120 parts of phosgene are passed in and fractionated in the course of ~ 1.5 hours while keeping a watchful eye then the mixture in vacuo. At 1 Torr go in the boiling range of 83 to 85 ° C 321 parts of glutaryl chloride over. So the increase in glutaryl chloride is 152 Parts, corresponding to a yield of 90% of theory.

Example 3 A solution of 200 parts of dichloromaleic anhydride and 4 parts of dimethylformamide in 175 parts of benzene is at a temperature of 65 to vaQc in a bubble column fed 24Q parts of phosgene within 3 hours. The solvent is then distilled from the reaction mixture under normal pressure from, the residue is fractionated in vacuo and obtained in the boiling range from 60 to 65 ° C / 2 Torr 234 parts of dichloromaleic acid dichloride, corresponding to a yield of 88 % of theory.

Example 4 Into a mixture of 204 parts of acetic anhydride and 5 parts Dimethylaniline are stirred at a temperature of 7000 within 3 Hours 220 parts of phosgene initiated. The distillation of the reaction mixture gives in the boiling range 51 to 52 ° C / 760 Torr 257 parts of acetyl chloride, corresponding to one Yield of 82% of theory.

Example 5 In a solution of 50 parts o-phthalic anhydride and 2 Parts of dimethylformamide in 260 parts of xylene are added with stirring at a temperature 250 parts of phosgene were introduced from 120 ° C. in the course of 9 hours. During the implementation are noqh 2 parts of dimethylformamide slowly. After cooling to room temperature the trot reaction solution is filtered, then the solvent is distilled off and the residue fractionated in vacuo. At 1 Torr go in the boiling range of 100 up to 105 ° C 56 parts of o-phthalyl chloride, corresponding to a yield of 83% the theory.

Example 6 In a solution of 163 parts of 2-naphthoic anhydride and 5 parts of dimethylformamide in 60Q parts of benzene is stirred at a temperature initiated 60 parts of phosgene from 65 ° C within 1 hour. Then filtered the reaction solution, the solvent is distilled off and the residue is fractionated in a vacuum. At 2 torr, 154 parts of 2-naphthoyl chloride go in the boiling range from 120 to 122 ° C about, corresponding to a yield of 79% of theory.

Beianiel 7 In a solution of 105 parts of dichloroacrylaic anhydride and 2 parts of dimethylformamide in 150 parts of benzene is at a temperature of 60 ° C., 50 parts of phosgene were introduced into a circulation apparatus over the course of 30 minutes. The reaction solution is filtered, the solvent is distilled off and fractionated the residue in a vacuum. At. 100 Torr goes in the boiling range of 83 to 840C 105 Divide dichloroacrylic acid chloride, corresponding to a yield of 82% of theory.

The other examples given in the table are carried out analogously to the aforementioned examples, to which reference is made in column 2 in each case. TABEL , Bei- aalog Aisgangsver-Tei-Katalyea-Tei-Zoeunge'-parts Tempe-duration parts Kp ° C / Torr Auabeut epiel example b3ndixng le tor le mid ratur hour Phos-des, nd- , o parts 5b gene substance a 4 Crotonsuxe'I7 Di. methyl- 2--65 1 60 120-122 / 96 g snhydrid (formamide? 60 9 6 oT. oluyla, u- 63 2 Henzol 200 60 0.5 35 55-59 / 1 61 79 anhydride 10 6 Allyl amber 140 "3 Benzene 130 65 1.5 120 106-1Q9 144? 4 eteinure- arrhydride 1 4 2-: Ethylhexane 135 '2 ~ -65 1 60? 3-? 5/15 96 acid anhy- 12 drid 12 6 Amber 100 "2 Henzol 175? 5 3 180 87-89 / 130 8 ° eaureanhy-'22 cirid 13 4 Esaig acid-102 "2 -'- 90 1 110 51 5/143 91 anhydride; ? 60 ' :, 14 2 Dihlorma-100 ° '2 dichloro-100 85 2 150 60-62 / 2 111 91 linseed-melein- ' anhydri, d eguredi- chloride 15 6 Phenyleasig-84 "2 Benzene 100 6 0, 5 40? 3-? 4/3? 9? eureanhy- drid egg-e. nalog Auegangver-T3-Katalyes Tei-Zogungs -teile Tempe-Deuer parts Kp ° CTorr usbeute game example binding le tor le midrature hour Phos-des End-Tile oC against shock 16 4 B-crotyl-231 amethyl-6--65 2 180 91-95 / 2 260 83 berns te in-f ormamici eaureanhy- ' drid 17 4 Hexahydro-1 ¢ 3 "3 ~ ~ 60-1? 5? 3-76 / 20. 161 92 benaoeaeu- ~ rearthdrid

Claims (1)

Claim process for the production of carboxylic acid chlorides, characterized in that one carboxylic acid anhydrides with phosgene at a temperature between 20 and 150 ° C.