DE1695870A1 - The production of lactams from cycloalkanes - Google Patents

Description

License plate 1942

Dr. F. Zumsfeln - Dr. E. Assmann

Dr. R. Koenigshcrger

Dipf. Phys. K. Hohbauer

Pafeniqr.wälfs

Munich 2, Bräuhaussfrafja 4 / III

STAMICARBON KrV., HEERLEK (the Netherlands) The manufacture of -.lactams from cycloalkanes

The invention relates to the production of lactams from cycloalkanes by photochemical means.

It is known that the corresponding cycloalkanone oxime is formed by reaction of a (cyclo) aliphatic hydrocarbon with a nitrosating agent, usually nitrosyl chloride, under irradiation (so-called photonitrosation). In this photochemical reaction with nitrosyl chloride, it is recommended (French patent 1,334,190) to add an excess amount of hydrogen chloride, whereby the oxime is obtained as a liquid oxime hydrochloride λ and undesired, more extensive reactions with nitrosyl chloride are avoided.

It is also known (French patent 1,335,822) that in the said photonitrosation added sulfuric acid to the reaction mixture causing an impairment of the radiation by standing on the walls Oxime hydrochloride deposited in the reaction vessel avoided and the formed Oxime is dissolved in the sulfuric acid. In the solution obtained can the oxime can be converted to lactam by heating. In the photonitrosation of cyclododecane (French patent

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scripture 1,364,653) canoe the deposition of Cyelododecanonoxiinnydroehlorid, that is difficult to completely liquefy - avoid and eliminate it The reaction mixture can be promoted by putting the cyclododecane together with a cycloalkane with a maximum of 8 carbon atoms, e.g. cyclohexane, subjected to photonitrosation. In this way it becomes a liquid mixture obtained from oxime hydrochlorides, which excreted from the reaction mixture will.

Experiments have now shown that undesirable deposits on the wall of the reaction vessel and impairment of the irradiation can be avoided in a simple manner if nxtrosyl chloride reacted with a nitrile and cycloalkane under irradiation and the ω-lactam corresponding to the cycloalkane is obtained from the reaction product will.

A process has been found for the production of lactams from cycloalkanes with the aid of hitrosyl chloride, which can be replaced by NO in addition with Cl and hydrogen chloride under irradiation at a temperature of -10 to 90 C-, which new process is characterized in that nitrosyl chloride (that can be replaced by NO together with Cl ₀ ) with cycloalkane and dissolved therein, at least partially present as Nxtrileliiorwassersto.ffverbindungen available nitrile, which does not contain any Nitrosylchloride -reacting CH "groups in the molecule, can react in a homogeneous liquid phase, the amount Nitrile in the reaction mixture is kept at at most 1 mole per mole of nitrosyl chloride and the reaction product formed is converted into the cycloalkane-corresponding a) -lactam by heating at a temperature of 40-150 ° C.

In the process according to the invention, a cycloaican is used as a solution Nitrile carried out a photochemical reaction. The nitrile underreacts the present reaction conditions first with hydrogen chloride, whereby

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it is present at least in part as a nitrile hydrochloride compound. Both the corresponding imino chloride and its hydrochloride can be formed as the hydrogen chloride compound. The amount of nitrile bound by hydrogen chloride is determined by the amount of hydrogen chloride used. However, it is not necessary that all nitrile is converted into a nitrile hydrochloride compound. A nitrile hydrochloride compound is always formed, even if no hydrogen chloride is added, because hydrogen chloride is formed in situ during the photochemical reaction with nitrosyl chloride. . . m

The amount of hydrogen chloride can be varied. Usually one cares by introducing a stream of hydrogen chloride gas into the reaction mixture during the reaction ensures that the reaction mixture is saturated with hydrogen chloride remain. Chlorine can also be passed in, which ensures a smooth course of the reaction is promoted.

By introducing these gases - nitrosyl chloride can also be gaseous are added - the reactionary mixture is stirred; furthermore can by application a stirring device promotes a good mixture of the reacting substances will.

In contrast to the well-known photonitrosation of cycloalkane, becomes ™ in the photochemical reaction according to the invention with nitrosyl chloride that Cycloalkanone oxime or its hydrochloride was not obtained as a reaction product. In the process according to the invention, the nitrosyl chloride reacts with the cycloalkane and the nitrile and / or the nitrile hydrogen chloride compound, wherein Cycloalkylimino-a-imino-a-alkyl ethers from an aliphatic nitrile or cycloalkylimino-a-imino-a-aryl ether is formed from an aromatic nitrile, which ether is bound by hydrogen chloride as hydrochloride.

The nitriles used according to the invention contain in the molecule none reacting with nitrosyl chloride under the present reaction conditions CH groups. When using nitriles, what kind of

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contain reactive CH ₉ groups, photonitrosation of the nitrile occurs, as a result of which the photochemical reaction according to the invention is hindered and the desired ether compound is not formed or is only formed to a small extent.

Examples of suitable nitriles are: benzonitrile, acetonitrile, dichloroacetonitrile, Trichloroacetonitrile, chlorobenzonitrile and naphthonitrile.

It is advisable to keep the amount of nitrosyl chloride in the reaction mixture to be kept low by adding nitrosyl chloride during the reaction. The concentration of the nitrosyl chloride is preferably 0.5 to 2% by weight of the cycloalkane held. -

Maintaining a homogeneous liquid phase during the reaction can be achieved by using inert under the reaction conditions Solvents are promoted. Examples of suitable solvents are: Benzene, ether, chloroform, carbon tetrachloride, chlorobenzene and tide mixtures this solvent,

When using cycloalkanes which are solid at normal temperature, e.g. Cyclododecane can also dissolve with the help of solvents Nitrile are promoted in the cycloalkane.

Because of the interaction that occurs between nitrile and nitrosyl chloride the amount of nitrile used is at least 1 mole each Moles of nitrosyl chloride; Usually amounts of 1-25 moles of nitrile per mole Nitrosyl chloride used.

The amount of nitrile and / or solvent should be so large that? a homogeneous liquid phase can be maintained during the reaction can, so that the reaction product formed as a solution in the reaction mixture is obtained.

The reaction with nitrosyl chloride is in the case of nitrosation

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Reactions rait nitrosyl chloride Usual temperature of -10 to 90 G carried out. ■■■■ ;.

_{The radiation sources T which are} generally applicable in photochemical reactions, for example gas discharge lamps, such as fluorescent lamps and mercury lamps, can be used for the irradiation. Light of higher wavelengths, such as sun * or artificial light (incandescent lamps, natural ampen), can also be used.

The imino ether hydrochloride formed can easily be

eg by evaporation and crystallization, precipitate from the reaction mixture in which Λ it is dissolved. The product obtained can then be converted into the γ-lactam corresponding to the cycloalkar by heating to a temperature of 40-150 ° C., preferably with the aid of a solvent, in the presence of hydrogen chloride. This conversion to lactam can also take place in the solution in which the reaction product is obtained.

Because the reaction with nitrosyl chloride at a temperature of -10 is carried out up to 90 C, is a simple embodiment of the invention Process possible if the aforementioned reaction takes place at a temperature of 40-90 ° C. A separate heating of the reaction

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Mixture at 40-150 C is unnecessary in this case if a temperature over 90 C is not required.

Will react with nitrosyl chloride at a lower temperature carried out, the reaction mixture is then briefly, e.g. 5, 10, 25 or 45 minutes, kept at a temperature of 40-150 C to allow the reaction promoted to lactam.

During the conversion of the imino ether hydrochloride formed into lactam the nitrile used is recovered. When adding nitrile to the The reaction mixture can be the nitrile recovered in the reaction mixture

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Accounted for grazing; recovered nitrile and hydrogen chloride can also be used be recirculated /

The lactam can be eliminated from the reaction mixture in a simple manner Manner, e.g. by distillation «

According to this process, cycloalkanes are converted into the corresponding ω-lactams produced, e.g. from Cyclöhexaa the e-caprolactam, from cyclooctane the iU-caprylolactam and from cyclododecane the ω-laurolactam. Even Mixtures of cycloalkanes can be used; from this then Get a mix of the corresponding öJ-Eactams.

Example I.

In a mixture of 1000 g of cyclododecane, 200 g of benzonitrile and 1000 g of benzene is placed under the liquid level with a cooling jacket 70 watt mercury lamp provided.

Nitrosyl chloride is produced at a rate of 5 g per hour introduced into the solution, the temperature rising under irradiation 30-35 C. Continuous introduction of hydrogen chloride ensures that the solution is saturated with hydrogen chloride remain.

After a reaction time of 8 hours, the homogeneous reaction mixture is heated at a temperature of 80 ° C. for 15 minutes. With cooling up to at 25 C a laurolactam hydrochloride-containing layer and a Hydrocarbon layer. The first layer is eliminated and extracted with cyclohexane, after which benzonitrile was recovered from the extract will. The remaining laurolactam hydrochloride is placed in water; the laurolactam formed as a solid is eliminated by filtration. ; ■

In this way, 65 g of cyclododecane are reacted; become out of this

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66 g of laurolactam (melting point 153 C) obtained (yield 86%).

If this experiment is repeated, with the difference that instead of nitrosyl chloride, 3.8 _{liters of NO and 1.7 liters of Cl 0 are} now introduced into the solution per hour, after 8 hours 41 g of cyclododecane and 30.3 g of Oi -Laurolactam has been obtained (yield 63%).

example II

The experiment described in Example I is repeated. In

In this case, after a reaction time of 8 hours, the reaction mixture is up to

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cooled to 20-25 ° C., after which ~ hydrogen chloride is recovered by the homogeneous solution. Included two layers are formed, namely a hydrocarbon layer and a layer in which benzonitrile and the cyclododecylimino-a-imina-benzyl ether hydrochloride formed are located. The structural formula of the ether is shown in FIG.

The ether hydrochloride layer is precipitated and 15 min at heated to a temperature of 80 C. This is followed by extraction recovered with cyclohexane benzonitrile. ·

The remaining Laurolactamhydrochlorid is hydrolyzed to the game, assisted Ä I described manner with water. The result is the same as in the example !. - -

example III

In a corresponding manner as described in Example I, a homogeneous mixture of 1000 g of cyclohexane, 1000 g of benzene and 500 g of benzonitrile is reacted with nitrosyl chloride. The feed rate of nitrosyl chloride is 8 g per hour; the reaction temperature is kept at 20-25 ° C. ■

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After a reaction time of ten hours, the reaction mixture becomes homogeneous

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Heated for minutes at a temperature of 70 C. With cooling up to 20 C a hydrocarbon layer and a layer in which the reaction product is located are formed. The caprolactam hydrochloride-containing layer is excreted, extracted with cyclohexane (recovery of benzonitrile), then placed in water and neutralized with ammonia. By extraction with chloroform and excretion of this solvent becomes e-caprolactam won.

In this way, 67 g of cyclohexane are reacted; 54 g of caprolactam (melting point 68 C} are obtained from this (yield 60%).

Example IV

A. In a similar manner as described in Example I, a mixture from 220 g of cyclododecane, 15 g of acetonitrile and 80 g of benzene with nitrosyl chloride brought to reaction. The feed rate of nitrosyl chloride is 2 g per hour; the reaction temperature is kept at 30-35 ° C.

During the reaction Cyclododeeylimino-Ot-imino-äthylätherfc separates hydrochloride as a solid from the homogeneous liquid. After a

The reaction time of 2 hours, the solid formed is separated off by filtration and washed with cyclohexane.

The amount of solids obtained is 14 g (melting point 136 ° C.). On analysis, this substance is identified as the hydrochloride of cyclododecylimino-o-imino-ethyl ether identified (See for structural formula Fig * 2).

B. In a corresponding manner as described in Example I, one of 220 = g of cyclododecane, 15 g of acetonitrile, 100 g of benzene and 100 g of chloroform Mixture reacted with nitrosyl chloride. The feed rate of nitrosyl chloride is 4 g per hour; the reaction

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temperature is kept at 30-35 ° C. After a reaction time of 3 hours the homogeneous reaction mixture heated for 30 min at a temperature of 65 ° C. Then chloroform and acetonitrile are separated out by distillation; at the same time, part of the benzene is recovered. When cooling of the reaction mixture up to 20 C a hydrocarbon layer is formed and a layer containing laurolactam hydrochloride. The laurolactam hydrochloride is introduced into water and the laurolactam formed through Filtration won.

In this way, 26 g of cyclododecane are reacted; this becomes 27 g üJ-Laurolactam (melting point 153 C) obtained (yield 88%).

Claims (6)

PATENT CLAIMS 1. Process for the production of lactams from cycloalkanes with the help of nitrosyl chloride that can be replaced by NO together with Cl-, and hydrogen chloride under irradiation at a temperature of -10 to 90 C, characterized in that nitrosyl chloride that by NO together can be replaced with Cl _2, cycloalkane and dissolved therein, at least present for parts as Nitrilchlorwasserstoffverbindung nitrile which m in the molecule does not react with nitrosyl CH groups containing allowed to react in a homogeneous FlUssigkeitsphase, wherein the amount of nitrile in the reaction mixture to at least 1 Moles per mole of nitrosyl chloride and the reaction product formed is reacted by heating at a temperature of 40-150 C to give the cycloalkane corresponding ftJ-lactam. 2. The method according to claim 1, as described in the text and with reference to the Examples has been explained. 3. (O- lactams, obtained according to the method according to one of the preceding 1098 19/2163 Expectations.
4. Cycloalkylimino-a-imino-a-alkyl ethers and cycloalkylimino-Ot-imino-a-aryl ethers. - 5. Cyclododecylimino-CX-iminobenzyl ether
6. Cyclododecylimino-a-iminoethyl ether 109819/2163