DE1024515B - Process for the production of lactams - Google Patents

Description

Process for the preparation of lactams It is known that oximes cyclic ketones can rearrange into the corresponding lactams. This is usually done by treating the oximes with sulfuric acid or with acid chlorides, e.g. B. phosphorus pentachloride or chlorosulfonic acid.

It. it has now been found that Lactalne is available. from cycloaliphatisc.hen Keitoximen obtained with advantage if one in the process for the production of Lacta, men from cycloalipha, tables. Ketoximes by treatment with sulfuric acid and / or Oleum in place of the free. cycloaliphatic ketoximes whose hydrohalides are used.

-'VIan can e.g. B. from the oxime hydrohalide with cold sulfuric acid first drive out the hydrogen halide in the cold and then the mixture on the Warm up the transfer temperature. Another embodiment of the method exists that the oxime hydrobalogenide in a preheated sulfuric acid or gradually enters into a sulfuric acid-lactam mixture, giving birth of the hydrogen halide and the. Rearrangement to the lacta, m going on at the same time. When the reaction has ended, it is poured. the reaction mixture on ice and neutralized the acidic solution with alkaline substances. The resulting raw lacta.m is purified by distillation.

The rearrangement can be carried out with 100% sulfuric acid, oleum, but also with aqueous, z. B. 80% sulfuric acid are carried out. The necessary. Temperatures are between 80 and 170 ° C, advantageously around. 120 ° C. The quantitative liberated hydrogen halide can be used otherwise., z. B. at the Production of the oxime hydrohalides.

According to these processes, both the mostly crystallized Hyd, raw halides of cycloaliphatic oximes, which have 1 mol of oxime and 1 mol of hydrogen halide included, as well. the; liquid hydrohalides containing more than 1 mole of hydrogen halide contained on 1 mole of oxime. be relocated, e.g. B. the hydrochloride of cyclopentanomoxime, Cyclohexanone oxime, methylcyclohexanone oxime, cycloheptanone oxime, cyclooctanone oxime and decalonoxime.

The advantage of the invention. Method is that you can see the hydrohalides of the oximes readily use to Sbelle the free oximes and separation as otherwise required neutralization, waste and saves drying. In this way, the raw material basis for the production of La.cta: men. significantly expanded. Another advantage of the method is that it is essential. easier temperature control compared to the usual rearrangement of cycloa, lipophilic, atic ketoximes with sulfuric acid, oleum or acid chlorides, in which the considerable heat of the rearrangement that occurs is dissipated. got to. In the process according to the invention, the reaction temperature can be regulated by suitable addition of the oxime hydrohalide, without cooling or heating from the outside, so that it remains within the desired range, since the release of the halogenated water means that the oxime hydrohalide is mixed with sulfuric acid A large part of the heat is withdrawn from the reaction mixture. which is released during the rearrangement to lactarn.

It is particularly advantageous to initiate the rearrangement in a known way to add some lactam, z. B. to the sulfuric acid or to Olenm.

The lactams of w-aminocarboxylic acids obtained according to the process. are valuable intermediate products for the production of synthetic fibers.

Those mentioned in the examples. Parts are parts by weight.

Example 1 14 parts of crystallized cyclooetannolioxime hydrochloride (corresponding to 11.2 parts of free Oxiln) are at room temperature with 1 = 10 parts 80% sulfuric acid poured over it; in the process, about 2.8 parts escape with cooling Hydrogen chloride gas. After the evolution of gas has ended, the mixture is carefully heated to 110 ° C, until the localization reaction sets in, and then holds out. appropriate cooling the reaction temperature to 115 to 125 ° C. After the rearrangement has ended, the mixture is allowed to cool, the reaction mixture is poured onto ice and neutralized with 50% sodium hydroxide solution. The crude lactam which separates out is separated off and distilled. After distilling off of the water in vacuo gives 9.6 parts of practically colorless yi-cap.ryllactam, KP-0.4 114 to 116 ° C; F. 75 ° C. By shaking out the neutral, aqueous phase with ethylene chloride gives a further amount of caprylic lactam. Yield, 86% of theory.

In an analogous way, 60 parts of liquid cyclooctanone oxime hydrochloride are obtained (corresponding to 39 parts of free oxime), which contains about 1 additional hydrogen chloride, with 220 parts. 80% sulfuric acid 34 parts (87% of theory) of il-capryllactain; F. 76 ° C.

Example 2 225 parts, liquid cyclooctane.onaxime hydrochloride (corresponding to 150 parts, free oxime), the per mole of oxime hydrochloride about another 0.9 mole of hydrogen chloride contains, one leaves. while stirring in one! solution preheated to 110 to 120 ° C from 30 parts of 2j-Capryllac; tam in a mixture of. 58.5 parts of sulfuric acid (1000 / aig) and 1.5 parts of oleum (24%) are poured in. At the same time you give a mixture of 218.5 parts of sulfuric acid (100%) and 6.5 parts of Olenm (240 / aig). One regulates the inflow of the reactants so that the reaction temperature between, 115 and 125 ° C remains. The practically quantitatively escaping hydrogen chloride can again be used,.

When the reaction has ended, the mixture is allowed to cool and the reaction mixture is poured on 200 g of ice, introduces ammonia to neutralize the sulfuric acid and works, as described in Example 1, further on. This gives 163 parts (89% of theory) practically colorless γ-caprylic lactam; F. 75 ° C.

The rearrangement can also be carried out in place of the sulfuric acid-oleum mixture in. 10% oleum: to be carried out.

The s-oilantholactam is obtained analogously from cycloheptanone oxime hydrochloride. Bp B 143 ° C; F. 29 ° C. Example 3 134 parts of crystalline cyclooctanone oxini hydrochloride (corresponding to 106 parts of free oxime) are carried gradually with stirring in. one; Solution of 30 parts of i7-capryllactam preheated to 110 to 120 ° C in one Mixture of 58.5 parts of sulfuric acid (100%) and 1.5 parts of oleum (24%). At the same time, a mixture of 154.5 parts of sulfuric acid (100% strength) and Pour in 4.5 parts of oleum (24%). The supply of the reactants is regulated so that the reaction temperature remains between 115 and 125 ° C. Escape 22 Parts of hydrogen chloride. When the reaction has ended, it is allowed to cool and poured on 200 pieces: ice. Working up as described in Example 1, 122 is obtained Parts (871 / o, of theory) of colorless ri-capryllactam. Bp 4,114 to 116 ° C; F. 75 ° C. In an analogous manner, crystallized cyclopentanonoxini hydrochloride is obtained the A-valerolactam. KP-14 137 ° C; F. 40 ° C.

Example 4 To 60 parts of a mixture of 233 parts of sulfuric acid (100%) and 7 parts of oleum (24%) are added with stirring 30 parts of s-caprolactain, the temperature rises to about 110 ° C; well. one leaves immediately 184 parts of liquid Cyclohexanone oxime hydrochloride (corresponding to 120g-free oxime), which is about per mole of oxime hydrochloride. Contains 0.7 mol of additional hydrogen chloride (H Cl content 35%), and at the same time the remaining 180 parts of the sulfuric acid-oleum-Gemisclies flow in so that the reaction temperature remains between 115 and 125 ° C. About 63 parts escape Hydrogen chloride. When the reaction has ended, the mixture is cooled, poured onto 200 g of ice and works as described in Example 1 on. 1Uan receives 142 parts 93% of theory colorless s-caprolacta, m. Bp 135 ° C .; F. 70 ° C.

At. Place of the aforementioned sulfuric acid-oleum mixture can e.g. B. also a mixture of 60 g sulfuric acid (100%) and 175 g oleum (24%) be used. Yield 951 / o of theory.

Example 5 To 60 parts of a mixture of 131 parts of sulfuric acid (100%) and 4 parts of oleum (24%) are added to 30 parts of E-caprolactam with stirring. Then 85 parts of crystalline cycloliexanone oxime hydrochloride are added at about 115 to 125 ° C (Corresponding to 64 parts of free oxime) and at the same time the remaining parts of the oleic acid-oleum mixture so that the reaction temperature remains between 115 and 125 ° C. Escape it about 20 parts of hydrogen chloride. When the reaction is complete, ah, cool down and pour 200 g ice and neutralized by introducing it. of ammonia. The neutralized reaction mixture is, as described in Example 1, worked up. Nlan receives 89 parts (92% of the Theory) colorless f-caprola.ctam. Bp 10 135 ° C; F. 70 ° C.

Claims (1)

PATENT CLAIM A process for the preparation of lac, taines from cycloaliphatic ketoximes by treatment with sulfuric acid and / or oils, characterized in that their hydrohalogens are used in place of the free cycloaliphatic ketoximes. References considered: U.S. Patent No. 2,487,246.