DE1030332B - Process for the production of ª ‡ -chloroacrylic acid esters - Google Patents

Description

GERMAN

It is known that monomeric α-chloroacrylic acid esters by splitting off hydrogen chloride from dichloropropionic acid esters, which contain at least one chlorine atom in Have α-position to produce. In the known processes, the a, /? - dichloropropionic acid esters shown in a separate operation, e.g. B. by chlorination of acrylic acid esters, and then in converted in a second operation by elimination of hydrogen halide ΐηα-CMoracrylic acid ester. To older proposals can be α, / 3-dichloropropionic acid ester by reacting acrylic acid esters with chlorine in the gas state in the presence of N-substituted ones Carboxamides and primary, secondary or tertiary amines and the vaporous Dichloropropionic acid ester in a separate operation in the presence of halides of the metals of Group II of the Periodic Table in α-chloroacrylic acid esters and split hydrogen chloride.

It has now been found that α-chloroacrylic acid esters can be used of saturated alcohols in one operation in a simpler way if one Acrylic acid esters with chlorine in the gas state in the presence of salts of the metals of the I. subgroup or the II. to VIII. Group of the Periodic Table. Surprisingly, you get the α-chloroacrylic acid esters in good yields without any significant polymerization of the ester formed and without major formation of more highly chlorinated esters, the z. B. by addition of chlorine to α-chloroacrylic acid ester can arise. The α, / J-dichloropropionic acid esters formed in addition to the α-chloroacrylic acid esters can also be converted into α-chloroacrylic acid esters in a known manner.

Suitable catalytically active metal salts are, for. B. the chlorides, bromides, acetates and phosphates of calcium, strontium, barium, zinc, nickel and cobalt. The metal salts can also consist of salt-forming Components, e.g. B. from a metal oxide and phosphorus pentoxide, in the reaction space in the presence the reactants are produced. The catalysts / can be used as such or applied to Carriers such as aluminum oxide, silica, silicates, pumice stone can be used.

Suitable acrylic acid esters are, for. B. the esters of saturated aliphatic, cycloaliphatic or araliphatic alcohols. The acrylic acid esters of saturated short-chain aliphatic monoalcohols are particularly important. By adding small amounts of N-substituted acid amides and / or amines, the conversion can be increased and the formation of residues can be significantly reduced. Such additives are z. B. N-methylformamide, Ν, Ν-dimethylformamide, N-ethylformamide, N, N-diethylformamide, N-butylformamide, NN-dibutylformamide, process for preparation
of α-chloroacrylic acid esters

Applicant:

Badisdie Aniline & Soda Factory
Aktiengesellschaft, Ludwigshafen / Rhein

Dr. Herbert Friederich, Worms,

and Dr. Manfred Minsinger, Ludwigshafen / Rhine,

have been named as inventors

N-methylacetamide, N-methylpyrrolidone and amines, like ethylamine, propylamine, n-butylamine, dimethylamine, Diethylamine, Dipropylamine, Dibutylamiii, Trärhylamini and tributyl amine. As a rule, 0.1 to 3% of these additives are used, based on the Weight of the acrylic acid ester. Favorable conversion temperatures Keep between 150 and 500 ° C, but preferably between 200 and 300 ° C.

The chlorine used can be replaced by inert gases, e.g. B. nitrogen, are diluted. The amount of chlorine is expediently chosen so that there are 0.9 to 1.8 moles of chlorine per mole of acrylic acid ester. The procedure is preferably carried out at normal pressure; however, it can also be used with overpressure or underpressure to be worked.

The chlorination is advantageously carried out in a corrosion-resistant reaction vessel, e.g. B. in a reaction tube made of graphite or ceramic material which is completely or partially filled with the catalyst. Man but can also arrange the catalyst in one or more layers in the reaction vessel. That Process can be carried out cocurrently or countercurrently. It is particularly useful to pass the substances to be converted in cocurrent over the catalyst. From the from the reaction tube exiting reaction mixture can after separation of the liquid constituents the α-chloroacrylic acid ester in usually, e.g. B. by distillation, separate.

It is known from US Pat. No. 2,588,852 that / 3-bromo ~ a-cMor- / 9-formylacrylic acid {= mucobromochloric acid) by treating furfural with bromine and chlorine in the presence of water. Even In this known process, the halogen does not attach to the double bond, but will this reaction carried out in the liquid state only at temperatures between 50 and 80 ° C.

809 527 / 4W

Claims (1)

The parts given in the examples below are parts by weight. example 1 It is placed in a corrosion-resistant, vertically arranged tube made of ceramic material of 1.20 m Length and 4 cm diameter 400 g of a catalyst containing 15% barium chloride based on aluminum oxide is upset. The pipe, which is heated to 240 ° C from the outside, is fed from above below 100 g per hour of methyl acrylate, which is stabilized with 0.1% hydroquinone. Simultaneously leads 100 g of chlorine per hour are added to the reaction tube from above. The reacmix emerging from the bottom of the pipe from 2000 g of methyl acrylate stabilized with 0.1% hydroquinone and 40 g of triethylamine reacted with 100 g of chlorine. The reaction products are worked up as in Example 1. You get in addition to 385 g of unreacted methyl acrylate, 1295 g of methyl a-chloroacrylate and 850 g α, / ϊ-dichloropropionic acid methyl ester. The amount of higher-boiling components is 355 g. Example 6 It is placed in a corrosion-resistant, vertically arranged tube made of ceramic material of 1.20 m Length and 4 cm diameter 400 g of a catalyst containing 10% cobalt bromide, which is based on aluminum tion mixture is passed through a cooler; the 15 oxide is applied. From the outside to 250 ° C The fractions that liquefy in the process are fractionally heated, and the tube is passed from top to bottom for hourly distillation. Hch 100 g of a vaporous mixture of 2000 g. After the throughput of 2000 g of methyl acrylic acid with 0.1% hydroquinone stabilized acrylic acid ester in addition to 510 g of unreacted acryl methyl ester and 10 g of dimethylformamide, this is obtained. Simultaneously methyl acid ester 986 g of methyl a-chloroacrylate, 20 100 g of chlorine per hour are introduced into the reaction tube _Bp . 50 = 55 to 56 ° C. and 730 g of _{methyl α, / ϊ-dichloropropionate, b.p. 20} = 72 to 73 ° C. The amount of higher-boiling fractions, _{b.p. 20} = 80 to 105 ° C., is 358 g. Example 2 The same reaction tube and the same catalyst as in Example 1 are used Pipe heated outside to 240 ° C is fed in from above from above. The reaction products are as in Example 1 worked up. In addition to 414 g of unreacted methyl acrylate, 1065 g are obtained α-chloroacrylic acid methyl ester and 1265 g a, /? - dichloropropionic acid methyl ester. The amount of the higher-boiling fractions is 69 g. Example 7 100 g of a vaporous tube made of ceramic material and measuring 1.20 m each hour are placed in a corrosion-resistant, vertical downwards direction Mixture of 2000 g with 0.1% hydroquinone stabili- length and 4 cm diameter 400 g of a catalyst, Sated acrylic acid methyl ester and 20 g of dimethyl containing 10% zinc chloride based on aluminum oxide formamide. At the same time leads main to the reaction tube is applied. From the outside to 270 ° C erje Hour 100g chlorine from above. The bottom of the heated pipe is passed hourly from top to bottom The reaction mixture emerging from the tube is mixed with a 35 100 g of a vaporous mixture of 2000 g Passed cooler, and the liquefied portions are fractionally distilled. In addition to 285 g of unreacted methyl acrylate 1395 g of methyl α-chloroacrylate and 866 g of methyl a, /? - dichloropropionate. The amount of the higher-boiling fractions is 280 g. Example 3 In the same reaction tube as in Example 1 and with the same catalyst are every hour 100 g of a vaporous mixture of 2000 g of methyl acrylate stabilized with 0.1% hydroquinone and 10 g of diethylamine reacted with 100 g of chlorine. The reaction products are as in Example 1 worked up. In addition to 360 g of unreacted methyl acrylate, 1,300 g of methyl α-chloroacrylate are obtained and 854 g of methyl α, / J-dichloropropionate. The amount of the higher-boiling fractions is 290 g. Example 4 is 107 g. Under the same conditions as in Example 1, 100 g per hour of a vaporous mixture are obtained from 2000 g with 0.1% hydroquinone, stabilized methyl acrylate and 20 g n-butylamine with 100 g of chlorine reacted. The reaction products are worked up as in Example 1. One receives besides 310 g of unreacted methyl acrylate, 1365 g of α-O-methacrylate and 485 g of methyl α, / 3-dichloropropionate. The amount of the higher-boiling fractions is 305 g. 0.1% hydroquinone stabilized methyl acrylate and 30 g dimethylformamide. Simultaneously leads 100 g of chlorine per hour are added to the reaction tube from above. The reaction products are as in Example 1 worked up. In addition to 390 g of methyl acrylate, 1125 g of methyl α-chloroacrylate and 1160 g of methyl α, / J-dichloropropionate. The amount the higher-boiling portion is 185 g. Example 8 In the same reaction tube as in Example 1 and with the same catalyst, 100 g of one vapor mixture of 2000 g of ethyl acrylate stabilized with 0.1% hydroquinone and 40 g of dimethylformamide reacted with 90 g of chlorine. The reaction products are worked up as in Example 1. In addition to 18 g of unreacted ethyl acrylate, 1305 g of ethyl chloroacrylate are obtained and 1425 g of ethyl α, / 2-dichloropropionate. The amount of higher boiling parts Example 5 Process for the production of α-chloroacrylic acid esters, characterized in that acrylic acid esters of saturated alcohols with chlorine in the gas state in the presence of salts of metals of the I. subgroup or the II. to VIII. group of the periodic system, advantageous in the presence of small amounts of N-substituted carboxamides or amines. Under the same conditions as in Example 1, 100 g of a vaporous product per hour © 809 527 / 4-77 5.58 Considered publications: U.S. Patent No. 2,588,852.