EP0000509B1 - Process for the manufacture of secondary aliphatic amines - Google Patents

Description

Secondary aliphatic amines, in particular the so-called fatty amines with long carbon chains, are today produced in large-scale industrial processes essentially by two basic procedures in varied variations, namely by the hydrogenation of corresponding nitriles or by the so-called aminolysis or ammonolysis, i.e. the reaction of fatty alcohols with ammonia or primary amines in the presence of hydrogen.

The hydrogenation of long-chain aliphatic nitriles to corresponding secondary amines has long been known. It is carried out on an industrial scale at medium to high pressures of approximately 20 to 300 bar and at elevated temperatures of approximately 130 to 260 ° C, both two-stage and one-stage processes being developed. A wide variety of contacts and contact systems based on nickel, cobalt, copper chromite are used as hydrogenation catalysts, which may also be doped with other metals and are frequently used in the form of fixed bed contacts. Such processes for the production of secondary amines from nitriles are known for example from DT-PS 936 518, DT-PS 1 280 243, DT-PS 1 941 290, US-PS 2 781 399, US-PS 2784232 and GB-PS 836 364.

In addition, the implementation of fatty alcohols with ammonia is becoming increasingly important for technical processes. Such a method is known in particular from DT-AS 22 55 701. Thereafter, long-chain fatty alcohols with ammonia in the presence of hydrogen over hydrogenation-dehydrogenation catalysts at atmospheric pressure can be converted into the corresponding secondary amines at temperatures of 120 to 250 ° C.

Furthermore, a process is known from DT-AS 1 219 493, according to which tertiary amines having 6 to 26 carbon atoms in each aliphatic group are prepared from mixtures of the corresponding aliphatic alcohols with corresponding nitriles, in which at temperatures between 160 and 280 ° C and at a pressure between 7 and 14 bar in the presence of hydrogenation catalysts, hydrogen is passed through the starting materials present in the liquid phase. Water vapor or ammonia formed during the reaction is removed from the reaction by the excess hydrogen passed through. Under these conditions, primary and secondary amines can practically only be obtained in minor amounts as by-products.

Finally, a process is known from DT-AS 15 43 317 in which alcohols and nitriles are converted to amides in the presence of anhydrous hydrogen fluoride and these amides are then hydrolyzed to mixtures of carboxylic acids and amines in the presence of hydrolysis agents. For large-scale production of fatty amines, this process is hardly considered, if only because of the laborious isolation of the pure amine from the hydrolysis mixture.

Secondary amines with long C chains are of great technical interest, in particular with regard to their further processing into the corresponding quaternary ammonium salts and their use as plasticizers for textiles. On the other hand, their preparation by the various processes always encounters particular difficulties since the primary amine-secondary amine tertiary amine is relatively easy to obtain the initial or final stage in the reaction chain, but the intermediate, namely the secondary amine, is much more difficult to obtain in high yields. However, there was a need to use the technically interesting reaction of fatty alcohols with fatty nitriles for the production of secondary fatty amines.

worin R₁ einen geradkettigen oder verzweigten, in a-Stellung jedoch höchstens einfach verzweigten Alkyl-, Alkenyl- oder mehrfach äthylenisch ungesättigten Kohlenwasserstoffrest mit 8 bis 26 C-Atomen oder einen Alkoxyalkylrest der Formel R2(OX)m- mit einem Molekulargewicht von mindestens 130, in welcher R₂ ein geradketiger oder verzweigter Alkyl-, Alkenyl- oder mehrfach äthylenisch ungesättigter Kohlenwasserstoffrest mit 1 bis 26 C-Atomen, X ein Rest ―CH₂CH₂―, -CH(CH3)-CHZ oder ―CH₂―CH(CH₃)― und m eine ganze oder gebrochene Zahl zwischen 1 und 20 sein kann und innerhalb von m auch Kombinationen der Reste X vorliegen können, bedeutet,
oder Gemische solcher Alkohole mit aliphatischen Nitrilen der Formel

worin R₃ einen geradkettigen oder verzweigten Alkyl-, Alkenyl- oder mehrfach äthylenisch ungesättigten Kohlenwasserstoffrest mit 8 bis 26 C-Atomen oder den Rest eines Äthernitrils der Formel R₄―(OX)_n―O(CH₂)_p― mit einem Molekulargewicht von mindestens 130, in welcher R₄ ein geradkettiger oder verzweigter Alkyl-, Alkenyl- oder mehrfach äthylenisch ungesättigter Kohlenwasserstoffrest mit 1 bis 26 C-Atomen, X ein Rest der obengenannten Bedeutung, n eine ganze oder gebrochene Zahl zwischen 1 und 20 oder null und p 1 oder 3 sein kann, wobei innerhalb von n auch Kombinationen der Reste X vorliegen können, bedeutet,
oder mit Gemischen solcher Nitrile in einem Molverhältnis Alkohol:Nitril von 90:10 bis 10:90 mit mindestens 2 Mol Wasserstoff pro Mol Nitril in innigen Kontakt bringt, wobei während der gesamten Reaktionszeit eine Ammoniakkonzentration von 3 bis 75 Vol.-% im Reaktionsgas aufrechterhalten wird.It has now been found that this is possible using a process for the preparation of secondary aliphatic amines from aliphatic nitriles and aliphatic alcohols in the liquid phase while passing hydrogen through in the presence of hydrogenation-dehydrogenation catalysts at elevated temperatures and with removal of the water of reaction, which is characterized in that that aliphatic alcohols of the formula at temperatures of 120 to 260 ° C under practically pressure-free conditions

wherein R _{1 is} a straight-chain or branched, in the a-position, however, at most single-branched alkyl, alkenyl or polyethylenically unsaturated hydrocarbon radical having 8 to 26 carbon atoms or an alkoxyalkyl radical of the formula R2 (OX) m - with a molecular weight of at least 130 in which R _{2 is} a straight-chain or branched alkyl, alkenyl or polyethylenically unsaturated hydrocarbon radical having 1 to 26 C atoms, X is a radical ―CH ₂ CH ₂ -, -CH (CH3) -CHZ or ―CH ₂ ―CH (CH ₃ ) - and m can be an integer or fractional number between 1 and 20 and combinations of the radicals X can also be present within m,
or mixtures of such alcohols with aliphatic nitriles of the formula

wherein R _{3 is} a straight-chain or branched alkyl, alkenyl or polyethylenically unsaturated hydrocarbon radical having 8 to 26 carbon atoms or the remainder of an ether nitrile of the formula R ₄ - (OX) _n ―O (CH ₂ ) _p - with a molecular weight of at least 130, in which R _{4 is} a straight-chain or branched alkyl, alkenyl or polyethylenically unsaturated hydrocarbon radical having 1 to 26 C atoms, X is a radical of the abovementioned meaning, n is an integer or fractional number between 1 and 20 or zero and p Can be 1 or 3, where combinations of the radicals X can also be present within n,
or with mixtures of such nitriles in a molar ratio of alcohol: nitrile from 90:10 to 10:90 in intimate contact with at least 2 moles of hydrogen per mole of nitrile, maintaining an ammonia concentration of 3 to 75 vol .-% in the reaction gas during the entire reaction time becomes.

zu nennen, in der R, einen Alkylrest oder einen ein- oder mehrfach äthylenisch ungesättigten Kohlenwasserstoffrest darstellt, der insgesamt 8 bis 26 C-Atome besitzt. Solche Alkohole können in der Kette eine oder mehrere Kettenverzweigungen in Form sekundärer oder tertiärer C-Atome aufweisen, jedoch besitzen sie in der a-Stellung zur OH-Gruppe höchstens eine Verzweigung, das heißt es handelt sich um primäre oder sekundäre Alkohole. Nur beispielsweise seien genannt: n-Octyalkohol, 2- Äthylhexanol, Isoctylalkohol, Isononylalkohol, Laurylalkohol, Isotridecylalkohol, Oleylalkohol, Cetylalkohol und Stearylalkohol. Geeignet sind ferner Alkohole oder Gemische von Alkoholen, die bei der Hydrierung von natürlichen Fettsäuren beziehungsweise Fettsäureestern entstehen, wie zum Beispiel Talgfettalkohol oder Palmkernfettalkohole. Hierzu gehören auch die einfach bis mehrfach ungesättigten Alkohole, die bei der Hydrierung der mehrfach ungesättigten Fettsäure-ester der Tran- und Rapsölfettsäuren entstehen. Genannt seien ferner auch die wohlfeilen primären Alkohole mit bis zu 24 C-Atomen, erhalten durch den Äthylenaufbau nach dem Ziegler-Prozeß. Auch mehr oder weniger verzweigte Alkohole, wie sie durch Oxo synthesen aus geradkettigen oder verzweigten, mittel- oder endständigen ungesättigten Olefinen hergestellt werden, oder der aus lsononylaldehyd zugängliche Isooctadecylalkohol können als Ausgangsalkohole Verwendung finden. Als sekundäre Alkohole kommen beispielsweise solche in Frage, die nach den bekannten Verfahren der Direktoxidation von geradkettigen und verzweigten Paraffinen in Gegenwart von Borsäure zugänglich sind. Die Ausgangsalkohole können in Form beliebiger Gemische vorliegen. Bevorzugt sind geradkettige und verzweigte primäre Alkohole, die gesättigt oder ungesättigt mit 1 bis 2 äthylenischen Doppelbindungen sein können und die 14 bis 22, insbesondere 16 bis 18 C-Atomen aufweisen.As starting materials for the process according to the invention, on the one hand, aliphatic alcohols of the formula

to name, in which R represents an alkyl radical or a mono- or polyethylenically unsaturated hydrocarbon radical which has a total of 8 to 26 carbon atoms. Such alcohols can have one or more chain branches in the form of secondary or tertiary carbon atoms in the chain, but they have at most one branch in the a position to the OH group, that is to say they are primary or secondary alcohols. Examples include: n-octyalcohol, 2-ethylhexanol, isoctyl alcohol, isononyl alcohol, lauryl alcohol, isotridecyl alcohol, oleyl alcohol, cetyl alcohol and stearyl alcohol. Also suitable are alcohols or mixtures of alcohols which are formed in the hydrogenation of natural fatty acids or fatty acid esters, such as, for example, tallow fatty alcohol or palm kernel fatty alcohols. This also includes the mono- to polyunsaturated alcohols that are formed during the hydrogenation of the polyunsaturated fatty acid esters of trans- and rapeseed oil fatty acids. Also worth mentioning are the inexpensive primary alcohols with up to 24 carbon atoms, which are obtained through the ethylene build-up according to the Ziegler process. More or less branched alcohols, such as those produced by straight-chain or branched, middle or terminal unsaturated olefins by oxo synthesis, or the isooctadecyl alcohol accessible from isononyl aldehyde can also be used as starting alcohols. Suitable secondary alcohols are, for example, those which are obtainable by the known processes for the direct oxidation of straight-chain and branched paraffins in the presence of boric acid. The starting alcohols can be in the form of any mixtures. Straight-chain and branched primary alcohols which are saturated or unsaturated with 1 to 2 ethylenic double bonds and which have 14 to 22, in particular 16 to 18, carbon atoms are preferred.

Suitable starting alcohols in the process according to the invention are also ether alcohols such as those formed by oxethylation and / or oxpropylation of primary and secondary alcohols. In these ether alcohols, the radical R ₁ assumes the meaning R ₂ (OX) _m -. The units can be units derived exclusively from ethylene oxide or propylene oxide, or they can also be mixtures of such units, in statistical distribution or in the form of blocks. m means the average degree of oxyalkylation. Therefore, m can be both an integer and a fractional number, which is between 1 and 20, preferably between 1 and 8 and in particular between 1 and 3 for the starting alcohol component of the process according to the invention. R ₂ can be a straight-chain or branched alkyl, alkenyl or polyethylenically unsaturated hydrocarbon radical having 1 to 26, preferably 8 to 22, carbon atoms, but with the proviso that the molecular weight of the total R2 (QX) m is at least 130 should, since only such residues bring about a sufficiently low vapor pressure of the alcohol under the reaction conditions of the process according to the invention, which prevents the starting alcohol from being mixed with the water of reaction from the. Process is carried out. The ether alcohols mentioned can also be used in a mixture with the above-mentioned straight-chain or branched, saturated or unsaturated, primary or secondary alcohols.

in denen der Rest R₃ gleichfalls einen Alkylrest oder einen ein- oder mehrfach äthylenisch ungesättigten Kohlenwasserstoffrest darstellen kann, wobei hier jedoch zum Unterschied von den Ausgangsalkoholen auch in a-Stellung ein tertiäres C-Atom stehen kann. Im übrigen gilt bezüglich der Kettenverzweigungen in R₃ das gleiche, was für die Reste R₁ der Ausgangsalkohole gesagt wurde. Diese Reste R₃ weisen 8 bis 26 C-Atome auf. Bevorzugt sind geradkettige und verzweigte gesättigte Nitrile oder solche mit bis zu 3 äthylenischen Doppelbindungen, die 14 bis 22, insbesondere 16 bis 18 C-Atome aufweisen. Auch die Ausgangsnitrile können in Form beliebiger Gemische in den genannten Grenzen eingesetzt werden.The second reaction component in the process according to the invention are nitriles of the formula

in which the radical R _{3 can} likewise be an alkyl radical or a mono- or polyethylenically unsaturated hydrocarbon radical, but here, in contrast to the starting alcohols, a tertiary carbon atom can also be present in the a-position. Otherwise, the same applies to the chain branches in R _{3 as was} said for the radicals R _{1 of} the starting alcohols. These radicals R ₃ have 8 to 26 carbon atoms. Straight-chain and branched saturated nitriles or those with up to 3 ethylenic double bonds which have 14 to 22, in particular 16 to 18, carbon atoms are preferred. The starting nitriles can also be in the form of any mixtures within the limits mentioned.

The nitriles required as starting components in the process according to the invention are prepared from the same-chain carboxylic acids by known processes by reaction with ammonia under dehydrating conditions. Such nitriles are also accessible by the so-called ammonoxidation of hydrocarbons or by the nitrilization of alcohols with ammonia, which is preferably carried out on iron contacts.

Ether nitriles are also suitable as starting nitriles, the radical R ₃ then taking the meaning R4- (OX) nO (CH2) p-, in which R _{4 is} a straight-chain or branched alkyl, alkenyl or polyethylenically unsaturated hydrocarbon radical with 1 to 26 ° C. -Atoms, preferably with 8 to 22 carbon atoms. (OX) are here also units which are formed by oxyalkylation with ethylene oxide and / or propylene oxide and which in turn, if both oxyalkylate radicals are present, can be statistically distributed or in the form of block copolymers. The degree of oxalkylation n can assume the same values as m in the starting ether alcohols, but it can also become zero in the case of ether nitriles. Finally, the index p can be 1 or 3. The requirement also applies to the ether nitriles that the entire radical R4- (OX) nQ (CH2) p- should have at least the molecular weight 130. The ether nitriles mentioned can be prepared by known processes, for example those in which p = 1, by reacting chloromethyl ethers with copper cyanide, the corresponding chloromethyl ethers in turn being able to be obtained by reacting alcohols or oxyalkylated alcohols with formaldehyde and HCl. Ether nitriles in which the index p = 3 can be obtained via the corresponding ether alcohols, which in turn can be prepared by reacting alcohols or oxyalkylated alcohols with oxetane (1,3-propylene oxide).

The nitriles and / or ether nitriles which can be used within the abovementioned limits can also be present in the form of mixtures.

The starting alcohols and the starting nitriles are in the liquid phase during the reaction.

The implementation in the context of the method according to the invention takes place under depressurized conditions, that is to say practically under normal pressure. Small increases in pressure to about 0.5 to 1 bar overpressure, which result, for example, from the resistance of the lines and also from the overcoming of the liquid level as a result of the introduction of the gases, are as much a part of the practically unpressurized area as a slight underpressure, for example can result from a small pressure difference of the gas circulation pump on the suction side of the apparatus.

The temperature during the reaction according to the process according to the invention should be between approximately 120 and approximately 260 ° C., preference is given to working in a temperature range between approximately 180 and approximately 260 ° C. in order to achieve economical reaction rates. However, a noticeable conversion to the desired secondary amines is also taking place in the latter area at the temperatures below from 120 ° C., which may optionally be deliberately run slowly.

For the process according to the invention, such contacts are required as catalysts which simultaneously have a hydrogenation and a dehydrogenation function. These are preferably Nichel contacts, which can be in the form of the active Raney-Nickei types as well as in grain or powder form with or without a carrier material. The corresponding cobalt contacts or nickel-cobalt or nickel-cobalt-copper mixed contacts are also suitable, as are copper chromite catalysts, which can optionally be provided with additives of copper oxide, alkali or alkaline earth metals, such as, in particular, barium. The nickel and cobalt catalysts of the most varied types with and without additions of other metals and with supports and activators are particularly suitable for the process according to the invention. Manganese, iron oxide, zinc oxide, aluminum silicates, aluminum oxide and Si0 ₂ in the form of diatomaceous earth or as a blown synthesis product may be mentioned as additives and carriers. The nickel contacts deserve priority.

Pure precious metal contacts based on palladium and platinum are not very suitable, but they can be made useful by contacting them with dehydrogenation contacts, e.g. Raney copper or copper-chromium catalysts can be combined. After such mixing processes, it is fundamentally possible to mix two different commercially available contacts so that the desired hydrogenation-dehydrogenation properties are obtained.

The preferred temperature range of the process according to the invention depends to a certain extent on the type of catalyst. When using nickel catalysts, the temperature range from 180 to 200 ° C has proven to be particularly favorable. These temperatures can be easily adjusted, in particular in the case of high-boiling starting alcohols and starting nitriles from about 12 carbon atoms. For reactants with shorter chains, the optimal temperature cannot be set immediately from around 180 ° C. In this case, the reaction is started at 120 ° C. and a relatively small amount of the reaction gas is first introduced into the nitrile-alcohol mixture. At this temperature, the conversion into high-boiling secondary amines or their precursors begins. As the reaction progresses, both the temperature and the amount of gas can then be slowly increased.

Use instead of nickel contact the somewhat sluggish copper-chromium catalysts, the optimal reaction temperature is around 230 to 250 ° C. In this case, nitrile-alcohol mixtures from about 15 to 16 carbon atoms or those of approximately the same boiling point or corresponding vapor pressures can be set directly to the reaction temperature without having to go through a slow heating-up period.

The amount of catalyst for the process according to the invention depends not only on the type of contact but also on the reaction temperature chosen. Within the process according to the invention, it ranges between 1 and 6% by weight, based on the amount by weight of the reactants and calculated on active metal or metal oxide. When using, for example, approximately equimolar mixtures of alcohols with mixed C _1J C ₁ S nitriles, the required amount of contact with Raney nickel under otherwise identical conditions was 5% by weight at 180 ° C, 2% by weight at 200 ° C and at 210 ° C 1 wt .-%. At 210 ° C there were minor side reactions. The above figures apply to the one-time use of a fresh contact.

During the reaction, the reaction mixture must be offered at least two moles of hydrogen per mole of nitrile; an excess of hydrogen, which can be of any size, does not interfere. The amount of hydrogen that may be required for the hydrogenation of ethylenically unsaturated double bonds of the starting nitriles or alcohols must also be taken into account. Hydrogen must be offered to the reaction mixture from the start, since otherwise undesirable side reactions occur.

The hydrogen concentration present in the reaction gas is calculated from the ammonia concentration mentioned below as a difference against 100%. Here and in the following, the reaction gas is understood to be only the sum of hydrogen and ammonia.

It is crucial for the conversion of alcohols and nitriles to secondary amines by the process according to the invention that ammonia is also present in the reaction gas in addition to hydrogen during the entire reaction time. Care must therefore be taken to ensure that the ammonia does not escape in an uncontrolled manner, since an ammonia deficit significantly reduces the yield of secondary amine. Depending on the molar ratio of the reactants used, the ammonia concentration can be between 3 and 75% by volume in the reaction gas. It can be kept constant within this range during the entire reaction time or fluctuate within this limit. The limits mentioned can, in particular, be exceeded for a short time, and may even be slightly below. It is crucial, however, that the ammonia concentration be controlled so that it is essentially maintained within these limits during the reaction period. If the limit of the ammonia concentration in the reaction gas is undershot, then an increase must be made; if it is exceeded, the. Ammonia concentration. This applies both to ammonia components that are supplied or removed from the outside, and to those that arise from the reaction partners themselves.

The proportion of the reactants alcohol and nitrile can vary within wide limits in the process according to the invention, up to a molar ratio of alcohol: nitrile between 90:10 and 10:90. A molar ratio of alcohol: nitrile between 70:30 and 30:70 is preferred, and in particular the reaction between equimolar proportions of both partners, with an molar ratio of alcohol: nitrile between 60 being below equimolar with regard to the technical circumstances (for example the purity and uniformity of the starting materials) : 40 and 40: 60 should be understood. In the latter case, the ammonia concentration should be between approximately 3 and 60% by volume and preferably between 3 and 50% by volume. Advantageously, the ammonia concentration should remain more in the lower part of the range in the case of a large excess of nitrile and more in the upper part of the range in the case of a large excess of alcohol. In the latter case, there is also the requirement that a total of at least 1/2 mole of ammonia is to be offered per mole of excess alcohol.

Under the conditions of the process according to the invention and depending on the molar ratios of the starting components nitrile and alcohol, the gas velocity at which the reaction gas, possibly including inert gas, passes through the liquid phase or comes into intimate contact with it should be between 200 and 600 l Moving gas per kg of reactant mixture and hour These limits are not absolutely critical, but the reaction is slower at lower gas velocities, about 50 to 100 l per kg and hour. On the other hand, gas quantities above 600 l per kg and hour only offer advantages if it is ensured that the larger quantities can also be optimally distributed in the liquid phase. Above 1000 l per kg and hour, the gas quantity is mainly limited in terms of technical feasibility and economy. The intimate contact between liquid, gas and catalyst required for the reaction is usually produced by the gas being stirred or pumped around the liquid phase with the suspended contact is initiated or circulated directly. Jet reactors are particularly advantageous for such a circulation. In these, the liquid reaction material is intimately mixed with the catalyst and the reactive gases in a jet nozzle, as a result of which a particularly rapid reaction takes place. The jet nozzle simultaneously circulates the gas phase and separates the water of reaction outside the boiler. The highest possible amount of gas is also of great importance for the quick and easy discharge of the water of reaction formed. To accelerate the discharge of the water of reaction and to save costs, the reaction gas, that is to say the mixture of hydrogen and ammonia, can be diluted with portions of inert gases such as nitrogen or methane. Inert gases can be present in proportions of 0 to 50% by volume in the gas mixture in addition to the reactive gases hydrogen and ammonia. Such gases reduce the partial pressures of hydrogen and ammonia, but on the other hand they promote the important discharge of the water of reaction.

The reaction can be carried out according to the so-called open as well as the so-called closed mode of operation. The open procedure consists in that, with good stirring, hydrogen is passed through the reaction vessel charged with the reaction mixture of alcohol and nitrile, which at the same time contains the catalyst, at the required reaction temperature, the amount of Am necessary for maintaining the ammonia concentration in the reaction mixture if necessary moniak is fed with. The outlet of the apparatus is openly connected to the atmosphere via a descending cooler, which advantageously contains a template for the absorption of the water of reaction. The excess reaction gases leave the apparatus via an exhaust pipe.

The closed mode of operation, which can also be referred to as gas cycle mode, is the preferred embodiment of the method according to the invention. In terms of equipment, it differs from the so-called open mode of operation in that hydrogen and ammonia are circulated through a circulation pump by means of a highly effective condenser after the water of reaction has been condensed out. The used hydrogen and ammonia are fed into the equipment. The closed mode of operation can therefore be used with the same high yields of secondary amines with significantly smaller amounts of the two gases. The ammonia loss can still be kept particularly low if the separated water of reaction is advantageously set to about 90 ° C. and the exhaust gases can condense via a reflux condenser. Instead of an approximately 10% by weight ammonia water, a 1 to 3% by weight ammonia solution is obtained with this measure.

In the cycle gas mode, it can prove to be advantageous to withdraw a certain amount of gas from the cycle one or more times, that is to say in batches, during the process or continuously, and to introduce fresh gas as a replacement. This can prevent the accumulation of undesirable gases, such as those formed in small quantities by side reactions. The export and import of the gases can be used to regulate the ammonia, hydrogen as well as the inert gas concentration. In addition to the condenser, the apparatus for the cycle gas mode of operation of the process according to the invention also has a switchable device, with the aid of which excess or ammonia present in the cycle gas can be removed completely or partially.

The device for regulating ammonia is advantageously located in the bypass of the gas circuit of the apparatus. It comes into operation as soon as the desired ammonia concentration is exceeded. Said device can be, for example, a washing tower or stirred tank filled with liquid absorbent, but also an adsorption tower filled with solid adsorbents.

Water or aqueous sulfuric acid, for example, can serve as the adsorbent for ammonia in the device mentioned. Concentrated sulfuric acid can also be used, which is injected in doses at a certain point in the gas circulation if necessary.

The ammonia concentration in the reaction gas is monitored, for example, with the aid of an infrared analyzer, a process chromatograph, or also with the aid of another continuous analyzer, which supplies chemical or physical analysis values. The analyzer used can advantageously regulate the supply and discharge of ammonia automatically.

After the ammonia concentration has been reduced by the measures mentioned, it is necessary to replace the amount of gas removed with hydrogen, optionally in a mixture with inert gases, in the circuit.

As a particularly favorable measure, the ammonia concentration can be adjusted by means of a cooling unit which can both remove ammonia from the circuit and also release ammonia to it. Such a unit can be installed in both the main circuit and the secondary circuit.

With the so-called open mode of operation, there is no need for an ammonia regulation device because the gases are introduced directly into the apparatus in the correct composition. With both the open driving style and the circular gas driving style, it is important that the resulting water is quickly removed from the liquid reaction phase and the condensed amount can be measured in a template. The amount of water separated and the absorption of hydrogen are a measure of the course of the reaction. The completion of the reaction by the process according to the invention can be determined with the aid of the titratable alkalinity of the desired secondary amine.

The procedures were described from the point of view of a batch process. However, it is also possible to carry out the process according to the invention entirely or partially continuously, for example in a pipe system, in a plurality of reactors connected in series or in cascade-like reaction vessels.

Unsaturated nitriles and alcohols, as already mentioned above, can also be used in the process according to the invention. The unsaturated alkyl chains can contain both one and more double bonds. Examples include: oleyl alcohols with iodine numbers from 50 to 95, tallow fatty nitrile with an iodine number of about 50, and the nitriles of tranoleic and rapeseed oil fatty acids with iodine numbers greater than 100, furthermore oleyl nitrile and soybean oil nitrile. The process can be controlled so that both saturated and the corresponding unsaturated or partially unsaturated secondary amines are obtained. Copper-chromium catalysts are best suited for maintaining the double bonds. Unsaturated or partially unsaturated secondary amines can also be obtained from unsaturated nitriles and alcohols with nickel contacts. In this case, a reaction gas is particularly advantageous which, in addition to hydrogen, contains about 10 to 60, preferably 20 to 50% by volume of ammonia.

Saturated secondary amines from unsaturated starting components are most advantageously obtained when the ammonia content of the reaction gas is in the lower range of the specified limits and when the reaction gas is replaced by pure hydrogen after the end of the formation of the secondary amine. If necessary, the temperature can be increased and the amount of gas increased.

The process according to the invention for the formation of the secondary amine usually takes 1.5 to 4, preferably 2 to 3 hours. In extreme cases (with a high iodine number) approximately the same time is again required for the complete hydrogenation of existing double bonds. The post-hydrogenation phase can be shortened if the pressure is increased, for example at 4 to 10 bar.

The yield of amines obtained by the process according to the invention, calculated as percentages by weight, is about 90 to 99%, in most cases it is more than 95%, and is therefore almost quantitative. The difference consists of non-amine constituents, especially small amounts of decomposition products of the starting alcohols and nitriles, as well as impurities in starting materials of technical quality. The proportion of the desired secondary amines is 80 to 95 mol%, in most cases over 90 mol%, based on the total yield of amines equal to 100 mol%. The rest are primary and tertiary amines, with the primary amines often being completely absent. The color quality of the secondary amines obtained is very good.

Iodine color numbers of 0.2 to 2 units are certainly obtained (iodine color numbers according to DIN standard 6162). The secondary amines obtained generally do not require any special purification process by a distillation or absorption process for further processing.

It was known that the hydrogenation of nitriles to secondary amines can only be carried out satisfactorily under medium to high pressures. It is therefore surprising that the reaction of alcohols and nitriles in changing molar ratios can be carried out without pressure and still gives high yields of the desired * secondary amines. However, slight excess pressure can also be used in the method according to the invention.

The secondary amines which can be prepared by the process according to the invention are above all valuable intermediates. They are preferred for the production of plasticizers for textiles, components for organophilic ammonium bentonites and microbiocides, especially for the fight against bacteria, fungi and algae. They are also used for the production of antistatic agents, conditioning and preparation aids, for hair cosmetics and for synthetic fibers. Secondary amines with a total number of more than 20 C atoms can also be used for the liquid extraction of metals, such as tungsten, in strongly acidic solutions.

With regard to the two radicals attached to the nitrogen atom, the secondary amines which can be prepared by the process according to the invention can be converted into symmetrical secondary amines (both radicals consist of a pure hydrocarbon radical or of a hydrocarbon radical containing ethoxy and / or propoxy groups) and unsymmetrical secondary amines (a radical consists of a pure hydrocarbon residue and the other of an ethoxy and / or propoxy group containing hydrocarbon residue).

The invention is illustrated below by examples:

example 1

The apparatus consists of a reaction flask equipped with a gas inlet, with a stirrer, Contact thermometer and a Raschig column that can be heated to 90 ° C. A water separator is installed on this column, which can also be heated up to 90 ° C if necessary, if the concentration of the dissolved ammonia in the separated reaction water is to be kept as low as possible. There is a good intensive cooler on the water separator. This is followed by an absorption vessel with 1 normal sulfuric acid, in which ammonia that has been removed can be recorded by titrimetry. The reaction gas in the apparatus is circulated through a circulation pump. Hydrogen required for the reaction is introduced into the circuit in such a way that an overpressure of up to 0.1 bar can prevail in the apparatus. Exhaust gas can be taken off at the outlet of the apparatus. The H ₂ SO ₄ ― absorption vessel can be switched in such a way that the circulating gas can be passed over it both in full and in the bypass of the circuit. It is also possible to absorb the ammonia outside the circulating gas in the exhaust gas in an H ₂ SO ₄ absorption vessel.

280.0 g = 1.00 mol of stearyl nitrile (N content 5% by weight according to Kjeldahl) and 1.86.6 g = 0.71 mol of stearyl alcohol (OH number = 214) are introduced into the apparatus just described. This corresponds to a proportion of 58.5 mol% of nitrile in the reaction mixture. 23.3 g = 5% by weight (based on the mixture of the reactants) of a nickel catalyst on a support with 55% by weight of nickel are then added and the apparatus is flushed with nitrogen. After the nitrogen has been displaced by hydrogen, the outlet of the apparatus is closed and the circulation pump switched on. There will be 300 l of cycle gas / kg. Hour drive. After heating to 200 ° C., the batch is run at this temperature for 3 hours, and 52.6 hydrogen are fed in during this time. The ammonia concentration in the cycle gas is kept in the range between 3 and 25% by volume by removing 2 l of waste gas. After the reaction has ended, the product is allowed to cool to 100 ° C. in a circulating gas stream and the apparatus is flushed with nitrogen. A total of 0.131 moles of ammonia are collected in the sulfuric acid receiver in the exhaust line. The water of reaction formed (16.3 g) contains a further 0.023 mol of ammonia. The flask contents are then sucked off at approx. 80 ° C through a diatomaceous earth filter through a suction filter. There are 96.3 wt .-% total yield of amine with an amine number of 17.40. It is composed of 92.1 mol% of secondary amine, the rest is tertiary amine, primary amine was not found.

Example 2

• 280,0 g = 1,00 Mol Stearylnitril (N-Gehalt 5 Gew.-% nach Kjeldahl)
• 262,0 g = ₁,00 Mol Stearylalkohol (OH-Zahl = 214) und 27,0 g ( = 5 Gew.-%, bezogen auf die Mischung der Reaktanten) eines Nickelkatalysators auf einem Träger (Gehalt 55 Gew.-% Ni). Nach Stickstoffspülung und Verdrängung des Stickstoffs durch Wasserstoff werden, wie in Beispiel 1 beschrieben, 300 I Kreisgas/kg. Stunde in der Apparatur gefahren. Dabei wird auf 200°C aufgeheizt und der Ansatz 2 1/2 Stunden gefahren, wobei während dieser Zeit 50,6 I Wasserstoff und aus einer Kälterfalle 2,78 g=0,163 Mol Ammoniak in den Kreislauf eingefahren werden, wodurch die Ammoniakkonzentration über die Reaktionszeit im Bereich von 12 bis 27 Vol.-% gehalten wird. Die Aufarbeitung erfolgt wie in Beispiel 1. Es fallen 20,1 g Reaktionswasser an, die 0,034 Mol Ammoniak enthalten. Im Absorptionsgefäss der Abgasleitung werden weitere 0,147 Mol Ammoniak aufgefangen. Es resultiert eine Gesamtamin-Ausbeute von 97,3 Gew.-% mit einer Aminzahl von 17,73. Das Produkt ist frei von primärem Amin, es enthält 96,6 Mol-% sekundäres Amin und 7,4 Mol-% tertiäres Amin.

The following are presented in the circulatory apparatus described in Example 1:

• 280.0 g = 1.00 mol of stearyl nitrile (N content 5% by weight according to Kjeldahl)
• 262.0 g = _1, 00 mol of stearyl alcohol (OH number = 214) and 27.0 g (= 5 wt .-%, based on the mixture of the reactants) of a nickel catalyst on a support (content 55 wt .-% Ni ). After purging with nitrogen and displacement of the nitrogen by hydrogen, 300 l of cycle gas / kg are, as described in Example 1. Hour in the apparatus. The mixture is heated to 200 ° C. and the batch is run for 2 1/2 hours, during which time 50.6 l of hydrogen and 2.78 g = 0.163 mol of ammonia are introduced into the circuit from a cold trap, as a result of which the ammonia concentration over the reaction time is kept in the range of 12 to 27 vol .-%. Working up is carried out as in Example 1. 20.1 g of water of reaction are obtained which contain 0.034 mol of ammonia. A further 0.147 mole of ammonia is collected in the absorption vessel of the exhaust pipe. A total amine yield of 97.3% by weight with an amine number of 17.73 results. The product is free of primary amine, it contains 96.6 mol% of secondary amine and 7.4 mol% of tertiary amine.

Example 3

• 148,3 g = 0,969 Mol Decannitril (entsprechend 74,8 Mol-% Nitril in der Mischung),
• 51,7 g = 0,327 Mol Decylalkohol sowie
• 10,0 g eines Träger-Nickelkontaktes (55% Nickel; 5 Gew.-% bezogen auf die Mischung).

The following are presented in the apparatus according to Example 1:

• 148.3 g = 0.969 mol decanitrile (corresponding to 74.8 mol% nitrile in the mixture),
• 51.7 g = 0.327 mol of decyl alcohol as well
• 10.0 g of a carrier-nickel contact (55% nickel; 5% by weight based on the mixture).

After purging with nitrogen and filling the apparatus with hydrogen, a circulating gas amount of 500 I circulating gas / kg. Set hour and the apparatus heated to 180 ° C. At this temperature, driving is carried out for 5 1/2 hours, during which time 58 l of hydrogen are introduced. When the reaction temperature of 180 ° C. is reached, the circulating gas contains 6% by volume of ammonia, 20% by volume after 1/2 hour and 34% by volume after 1 hour. Exhaust gas is now taken off via the H ₂ SO ₄ steilabsorbing part in the exhaust pipe, keeping the ammonia level at 35% by volume. After 2 and 3 hours of reaction time 35% by volume of ammonia are measured, after 4 and 5 hours 30.5% and 25% by volume, respectively. At the end of the reaction time, after 5 1/2 hours, the cycle gas still contains 15% by volume of ammonia. Up to this point, 13.6 l of exhaust gas have been continuously removed from the apparatus, which contain 0.181 mol of ammonia. 6.9 g of water of reaction are also obtained, containing a further 0.061 mol of ammonia. Finally, a further 0.029 mol of NH _{3 are} collected when the apparatus is rinsed. The total amine yield is 95.3% by weight with an amine number of 31.85. This contains 3.1 mol% of primary amine, 92.2 mol% of secondary amine and 4.7 mol% of tertiary amine.

Example 4

• 110 g = 0,719 Mol Decannitril (entsprechend 55,8 Mol-% Nitril in der Mischung),
• 90,0 g = 0,570 Mol Decylalkohol, sowie
• 10,0 g eines Träger-Nickelkontaktes (5 Gew.-% bezogen auf die Mischung; 55% Nickel).

The following are presented in the circulatory apparatus described in Example 1:

• 110 g = 0.719 mol of decanitrile (corresponding to 55.8 mol% of nitrile in the mixture),
• 90.0 g = 0.570 mol of decyl alcohol, and
• 10.0 g of a carrier-nickel contact (5% by weight based on the mixture; 55% nickel).

The circulating gas volume is set to 500 I / kg. Hour, it is heated to 180 ° C. and the batch is run at this temperature for 4 1/2 hours, during which time 36.4 l of hydrogen are added. When the reaction temperature is reached, 5% by volume of ammonia are contained in the cycle gas, 20% by volume after 1 hour and 30% by volume after 3 hours. Exhaust gas is not removed. The ammonia concentration then drops to 18% by volume at 3 hours and to 6% by volume at 4 hours. At the end of the reaction time after 4 1/2 hours, 3% by volume of ammonia are measured. 11.3 g of water of reaction are obtained which contain 0.065 mol of ammonia, and a further 0.011 mole of ammonia are collected when the apparatus is rinsed. The total amine yield is 97.4% by weight with an amine number of 31.47. Of these, 0.1 mol% are primary amine, 91.0 mol% secondary didecylamine and 8.9 mol% tertiary tridecylamine.

Example 5

• 48,0 g = 0,314 Mol Decannitril,
• 152,0 g = 0,962 Mol Decylalkohol und
• 10,0 g eines Nickelkatalysators auf einem Träger (5 Gew.-% bezogen auf die Mischung; 55% Nickel).

In the circulatory apparatus; described in Example 1 are submitted:

• 48.0 g = 0.314 mol decanitrile,
• 152.0 g = 0.962 mol of decyl alcohol and
• 10.0 g of a nickel catalyst on a support (5% by weight based on the mixture; 55% nickel).

The circulating gas volume is 500 1 / kg. Hour, the reaction temperature 180 ° C and the reaction time 4 1/2 hours. During this time, 15.4 l of hydrogen are fed in continuously and at the same time 8.0 g = 0.471 mol of ammonia from a cold trap for 3 1/4 hours, as a result of which an ammonia concentration of between 30 and 50% by volume is established during the entire reaction time. Exhaust gas is not removed. 19.5 g of water of reaction containing 0.147 mol of ammonia are collected in the water separator, and a further 0.048 mol of ammonia are collected when the apparatus is rinsed. The crude product obtained after removal of the contact contains 99.4% by weight of total amine with an amine number of 32.05. This contains 0.1 mol% primary, 90.3 mol% secondary and 9.6 mol% tertiary amine.

Example 6

• 99,5 g = 0,65 Mol Decannitril (entsprechend 50 Mol-% Nitril in der Mischung),
• 119,6 g = 0,65 Mol eines Octylalkohols, der mit 1 Mol Äthylenoxid oxäthyliert worden ist (Kp.₁₀
• 120 bis 125°C) sowie
• 10,0 g eines Nickelkatalysators auf einem Träger (5 Gew.-% bezogen auf die Mischung; 55% Nickel).

The following are presented in the circulatory apparatus described in Example 1:

• 99.5 g = 0.65 mol decanitrile (corresponding to 50 mol% nitrile in the mixture),
• 119.6 g = 0.65 mol of an octyl alcohol which has been oxethylated with 1 mol of ethylene oxide (bp. ₁₀
• 120 to 125 ° C) and
• 10.0 g of a nickel catalyst on a support (5% by weight based on the mixture; 55% nickel).

The circulating gas volume is 500 I / kg. Hour, the reaction temperature 180 ° C and the reaction time 5 1/2 hours. During this time, 32.9 liters of hydrogen are fed in continuously. After heating, the circulating gas initially contains 7% by volume ammonia, after 1/2 hour 25% by volume, after 1 hour 33% by volume and after 2 hours 35% by volume ammonia, without additional ammonia being added . The ammonia concentration in the cycle gas then drops again and is still 3% by volume at the end of the reaction time. 13.0 g of water of reaction are obtained, containing a further 0.034 mol of ammonia. The crude product obtained after removal of the contact contains 95.8% by weight of total amine with an amine number of 30.2. The determination shows that it contains 84.0 mol% of secondary amine, 16.0 mol% of tertiary amine and no primary amine, with sec. Amine (bp., ₃ 212-218 ° C) all 3 possible species can be detected by gas chromatography.

Example 7

• 107,0 g = 0,476 Mol Dodecyl-cyanmethyläther (entsprechend 52,4 Mol-% Nitril in der Mischung),
• 93,0 g = 0,433 Mol Myristylalkohol sowie 5,7 g eines wasserfeuchten Raney-Nickels mit einem Nickelgehalt von 70 Gew.-%, entsprechend 2 Gew.-% Nickel bezogen auf die Reaktionsmischung. Das eingesetzte Nitril und der eingesetzte Alkohol besitzen nach der gaschromatographischen Analyse eine Reinheit von etwa 97%.

The following are presented in the circulatory apparatus described in Example 1:

• 107.0 g = 0.476 mol dodecyl cyanomethyl ether (corresponding to 52.4 mol% nitrile in the mixture),
• 93.0 g = 0.433 mol of myristyl alcohol and 5.7 g of a water-moist Raney nickel with a nickel content of 70% by weight, corresponding to 2% by weight of nickel, based on the reaction mixture. According to the gas chromatographic analysis, the nitrile and the alcohol used have a purity of about 97%.

The circulating gas volume is 500 I / kg. Hour, the reaction temperature 190 ° C and the reaction time 6 1/2 hours. After the apparatus has been filled with hydrogen after nitrogen flushing, it is first heated to 140 ° C. and then gaseous ammonia is introduced in a proportion of 10% of the circulating gas volume. A total of 24.1 l of hydrogen are introduced during the entire reaction time, that is to say from 190 ° C. onwards. Ammonia accumulates rapidly in the circuit. Immediately after the reaction temperature has been reached, the ammonia concentration is 27% by volume, 60% by volume after 1/2 hour of reaction time and 67% by volume after 1 hour. The ammonia concentration in the cycle gas then drops again, to 1% by volume after 1 1/2 hours, to 19% by volume after 2 hours and to 2.9% by volume at the end of the reaction time. No exhaust gas is discharged. 8.2 g of water of reaction containing 0.013 mol of NH _{3 are} collected in the water separator heated to 90 ° C. Another 0.012 mol NH ₃ are discharged when the apparatus is finally rinsed.

After the contact has been separated off, a crude product is obtained which contains 94.5% by weight of total amine with an amine number of 21.08. This consists of 0.4 mol% primary, 88.3 mol% secondary and 11.3 mol% tertiary amine, all 3 possible species in secondary amines being detected by gas chromatography.

Example 8

• 105,0 g = 0,394 Mol Talgfettnitril (Jodzahl 57, N-Gehalt 5,25% nach Kjeldahl),
• 95,0 g = 0,362 Mol vollständig hydrierter Talgfettalkohol (OH-Zahl 214), sowie
• 5,7 g wasserfeuchtes Raney-Nickel mit einem Nickelgehalt von 70 Gew.-%, entsprechend 2 Gew.-% Nickel, bezogen auf die Reaktionsmischung.

The following are presented in the circulatory apparatus, described in Example 1:

• 105.0 g = 0.394 mol tallow fat nitrile (iodine number 57, N content 5.25% according to Kjeldahl),
• 95.0 g = 0.362 mol of fully hydrogenated tallow fatty alcohol (OH number 214), and
• 5.7 g of water-moist Raney nickel with a nickel content of 70% by weight, corresponding to 2% by weight of nickel, based on the reaction mixture.

The circulating gas volume is 500 1 / kg. Hour. After filling the apparatus with hydrogen, the mixture is heated to 200 ° C. with vigorous stirring. At a temperature of 140 ° C, a proportion of 10% of the circulating gas volume of gaseous ammonia is brought in. The reaction time is 2 1/2 hours at a temperature of 200 ° C, during which time 22, 1 I of hydrogen are continuously fed into the circuit. The ammonia concentration is 42% by volume at the beginning of the reaction, it drops to 33% by volume after 1/2 hour, to 18% by volume after 1 hour and to 11% by volume at the end of the reaction. During this time, 7.2 g of water containing 0.005 mol of ammonia are collected in the water separator, which is heated to 90 ° C. After the end of this reaction, a crude product results which contains 98% by weight of total amine with an iodine number of 20 and an amine number of 19.2, 4.3% by mol of primary, 93.1% by mol of selundary and 2 , 6 mol% consists of tertiary amine. This product is further treated at 200 ° C. for 3 hours in a cycle gas which has been freed of ammonia beforehand by passing it through dilute sulfuric acid. During this time, a further 3.9 l of hydrogen are added. After 1 hour the iodine number drops to 6, after 2 hours to 2 and after 3 hours to 1. The amine now obtained has an amine number of 19.09, it is free of primary amine and contains 95.3 mol% of secondary and 4 , 7 mol% tertiary amine.

Example 9

• 100,0 g = 0,382 Mol Talgfettnitril (Jodzahl 55, Stickstoffgehalt nach Kjeldahl 5,35%)
• 100,0 g = 0,381 Mol hydrierter Talgfettalkohol (OH-Zahl 214) und
• 5,7 g eines wasserfeuchten Raney-Nickels, Nickelgehalt 70%, entsprechend 2% bezogen auf die Reaktionsmischung.

The following are presented in the circulatory apparatus described in Example 1:

• 100.0 g = 0.382 mol tallow fat nitrile (iodine number 55, nitrogen content according to Kjeldahl 5.35%)
• 100.0 g = 0.381 mol hydrogenated tallow fatty alcohol (OH number 214) and
• 5.7 g of a water-moist Raney nickel, nickel content 70%, corresponding to 2% based on the reaction mixture.

The circulating gas volume is 500 1 / kg. Hour, the reaction temperature 200 ° C and the reaction time 5 1/2 hours. During the heating process, about 10% of the circulating gas volume of gaseous ammonia is again introduced into the circuit at 140 ° C., and hydrogen is also fed continuously. At the beginning of the reaction, 40% by volume are contained in the cycle gas, 24% by volume after 1/2 hour, 11% by volume after 1 hour and less than 4% by volume of ammonia at the end of the reaction. At this point there is a total amine with a yield of 96.8% by weight, which has an iodine number of 15 and an amine number of 18.93. It is 4.5 mol% of primary, 92.3 mol% of secondary and 4.5 mol% of tertiary amine. The cycle gas is then continued for a further 3 hours at 200 ° C. without ammonia being removed. Hydrogen continues to be supplied, so that the total amount of hydrogen supplied is 24.7 l in total. The ammonia concentration increases again during this time and is 7.4% by volume after 2 hours. The iodine number decreases and is 2 after 3 hours. After a total reaction time of 5 1/2 hours, a total amine with an amine number of 18.93 results, which contains 1.0 mol% primary, 92.7 mol% secondary and 6. Contains 3 mol% of tertiary amine.

Example 10

• 150,0 g = 0,573 Mol Talgfettnitril (Jodzahl 55, N-Gehalt nach Kjeldahl 5,35%),
• 50,0 g = 0,191 Mol hydrierter Talgfettalkohol (OH-Zahl 214) und
• 11,7 g eines wasserfeuchten Raney-Nickels, 70% Nickel-Gehalt, entsprechend 4 Gew.-%, bezogen auf die Reaktionsmischung.

The following are presented in the circulatory apparatus described in Example 1:

• 150.0 g = 0.573 mol of tallow fatty nitrile (iodine number 55, N content according to Kjeldahl 5.35%),
• 50.0 g = 0.191 mol hydrogenated tallow fatty alcohol (OH number 214) and
• 11.7 g of a water-moist Raney nickel, 70% nickel content, corresponding to 4% by weight, based on the reaction mixture.

The circulating gas volume is 500 1 / kg. Hour, the reaction time at 200 ° C 2 1/2 hours. During this time, 32.2 l of hydrogen are fed into the circuit. Ammonia is rapidly enriched in the circuit, so part of the circulating gas in the secondary circuit is passed through dilute H ₂ S0 ₄ in order to keep the ammonia concentration in the circulating gas between 35 and 50% by volume. 0.102 mol of ammonia are determined in the sulfuric acid, and a further 0.009 mol of ammonia are contained in the water of reaction (6.5 g). After this reaction time, a total amine results in a yield of 97.9% by weight with an amine number of 19.64, which consists of 7.2 mol% of primary, 90.9 mol% of secondary and 1.9 mol -% of tertiary amine exists (iodine number 26). The circulating gas is then run over dilute sulfuric acid for a further hour, a further 0.097 mol of ammonia being obtained, and a further 4.2 l of hydrogen are introduced during this time, additional reaction water does not arise. After this time, an amine with a residual iodine number of 4 and an amine number of 18.31 results, which is free of primary amine and consists of 97.6 mol% of secondary amine, the rest is tertiary amine.

Example 11

• 50,0 g = 0,191 Mol Talgfettnitril (Jodzahl 55, Stickstoffgehalt nach Kjeldahl 5,35%),
• 150,0 g = 0,572 Mol hydrierter Talgfettalkohol (OH-Zahl 214) und
• 5,7 g wasserfeuchten Raney-Nickels mit einem Nickel-Gehalt von 79 Gew.-%, entsprechend einem Anteil an Raney-Nickei von 2 Gew.-%, bezogen auf die Reaktionsmischung.

The following are presented in the circulatory apparatus described in Example 1:

• 50.0 g = 0.191 mol of tallow fat nitrile (iodine number 55, nitrogen content according to Kjeldahl 5.35%),
• 150.0 g = 0.572 mol hydrogenated tallow fatty alcohol (OH number 214) and
• 5.7 g of water-moist Raney nickel with a nickel content of 79% by weight, corresponding to a proportion of Raney-Nickei of 2% by weight, based on the reaction mixture.

The circulating gas volume is 500 1 / kg. Hour, the reaction temperature 200 ° C. During the reaction time, 10.5 l of hydrogen are continuously fed into the circuit; in addition, from a cold trap, 4.25 g = 0.241 mol of ammonia are introduced into the circuit from a cold trap once a temperature of 140 ° C. has been reached. During the ammonia injection period. If the ammonia concentration in the cycle gas is between 30 and 40% by volume, it then drops to 8% by volume after the end of the reaction time after 2 1/2 hours. After this time, a total amine results in a yield of 97.1% by weight with an iodine number of 10 and an amine number of 19.07. This total amine contains 3.9 mol% primary, 91.7 mol% secondary and 4.5 mol% tertiary amine. The cycle gas is then circulated at 200 ° C. for a further hour, passing through dilute sulfuric acid to remove the ammonia. During this time another 1.4 l of hydrogen are added. The result is an amine with a residual iodine number of 3 and an amine number of 18.92, which contains 1.3 mol% primary, 93.3 mol% secondary and 5.4 mol% tertiary amine.

Example 12

• 92,5 g = 0,355 Stearylnitril (Stickstoffgehalt nach Kjeldahl 5,34%),
• 107,5 g = 0,333 Mol Behenylalkohol (OH-Zahl 174), und 5,7 g wasserfeuchten Raney-Nickels Nickel-Gehalt 70%, entsprechend 2 Gew.-%, bezogen auf die Reaktionsmischung.

The following are presented in the circulatory apparatus described in Example 1:

• 92.5 g = 0.355 stearyl nitrile (nitrogen content according to Kjeldahl 5.34%),
• 107.5 g = 0.333 mol of behenyl alcohol (OH number 174), and 5.7 g of water-moist Raney-Nickel nickel content 70%, corresponding to 2% by weight, based on the reaction mixture.

There is a circulating gas volume of 500 I / kg. Set hour and heated to 200 ° C, the reaction time is 3.5 hours. During the heating process, gaseous ammonia is fed into the circuit in an amount of 10% of the circulating gas volume at 140 ° C. During the reaction time, 18 l of hydrogen are introduced into the circuit. When the reaction temperature reaches 200 ° C., the ammonia concentration is 39% by volume, 28% by volume after 1/2 hour, 15% by volume after 1 hour and 3% by volume at the end of the reaction time. A total amine results in a yield of 97.2% by weight with an amine number of 16.79, which consists of 1 mol% of primary, 94.3 mol% of secondary and 4.7 mol% of tertiary Amine exists.

Example 13

• 105,0 g = 0,401 Mol Talgfettnitril (Johzahl 55, Stickstoff-gehalt nach Kjeldahl 5,35%),
• 95,0 g = 0,362 Mol hydrierter Talgfettalkohol (OH-Zahl 212), und
• 17,2 g wasserfeuchtes Raney-Kobalt, Kobalt-Gehalt ca. 70 Gew.-%. entsprechend 6 Gew.-% Kobalt, bezogen auf die Reaktionsmischung.

The following are presented in the circulatory apparatus described in Example 1:

• 105.0 g = 0.401 mol of tallow fat nitrile (number of Joh 55, nitrogen content according to Kjeldahl 5.35%),
• 95.0 g = 0.362 mol of hydrogenated tallow fatty alcohol (OH number 212), and
• 17.2 g of water-moist Raney cobalt, cobalt content approx. 70% by weight. corresponding to 6% by weight of cobalt, based on the reaction mixture.

After filling the apparatus with hydrogen, a circulating gas circulation of 500 I / kg. Set hour and heated to 180 ° C with vigorous stirring. At a temperature of 140 ° C, gaseous ammonia is introduced into the circuit in an amount of 10% of the circulating gas volume. The reaction time is 8 hours, during which time 22.3 l of hydrogen are run in. Immediately after the reaction temperature has been reached, the ammonia concentration in the cycle gas is 13% by volume, 35% by volume after 2.5 hours, 21% by volume after 5 hours and 5% by volume at the end. A total amine results in a yield of 94.0% with an iodine number of 20 and an amine number of 17.97, 11.9 mol% of primary, 86.4 mol% of secondary and 1.8 mol% % consists of tertiary amine.

Example 14

• 105,0 g = 0,401 Mol Talgfettnitril (Johzahl 55, Stickstoffgehalt nach Kjeldahl 5,35%),
• 95,0 g = 0,362 Mol hydrierter Talgfettalkohol (OH-Zahl 214), und
• 4 g eines Kupfer-Chromit-Katalysators, entsprechend 2 Gew.-%, bezogen auf das Reaktionsgemisch.

The following are presented in the circulatory apparatus described in Example 1:

• 105.0 g = 0.401 mol of tallow fat nitrile (number of Joh 55, nitrogen content according to Kjeldahl 5.35%),
• 95.0 g = 0.362 mol hydrogenated tallow fatty alcohol (OH number 214), and
• 4 g of a copper-chromite catalyst, corresponding to 2% by weight, based on the reaction mixture.

Circular gas volume 500 I / kg. Hour, reaction temperature 250 ° C., reaction time 7 hours. At 140 ° C, ammonia is added in an amount of 10% of the circulating gas volume. Furthermore, during the reaction time 20.9 1. hydrogen are introduced. The ammonia concentration increases slowly, it is 25% by volume after 4.5 hours, and then slowly decreases again to 13% by volume at the end of the reaction. A total amine is obtained with a yield of 88.5% by weight, an iodine number of 27 and an amine number of 16.38. This consists of 10 mol% of primary, 82.3 mol% of secondary and 7.7 mol% of tertiary amine.

Example 1 5

According to Example 6, octane nitrile and tetraethylene glycol mono-n-butyl ether are circulated for 8 hours at 200 ° C. set. The circulating gas volume is 500 I / kg. Hour. The ammonia level in the cycle gas is 465% by volume at the start of the reaction and drops to 5% by volume towards the end of the reaction. 93.3% by weight of total amine with an amine number of 24.85 are obtained. Of these, 3.7 mol% are primary amine, 80.5 mol% secondary amine and 15.8 mol% tertiary amine.

147.4 g of this total amine are subjected to fractional distillation at 9 mm Hg pressure, the following fractions being obtained:

Die gaschromatographische Analyse wurde durchgeführt in einer 1,5 m hohen Säule von 2 mm Durchmesser, versehen mit einer Füllung von 5 Gew.-% "Silicon Fluid QF_;' auf "Chromosorg G-AW-DMCS" (zu beziehen durch die Firma Merck AG, Darmstadt); Trägergasströmung: 20 ml/min Stickstoff; Temperaturprogression: 80 bis 250°C mit 2°C pro Minute Steigung; Probenvolumen: 0,2 pl.The fraction passing at a head temperature of 232 to 236 ° C. contains 95% by weight of the compound according to gas chromatographic analysis

The gas chromatographic analysis was carried out in a 1.5 m high column of 2 mm diameter, provided with a filling of 5% by weight "Silicon Fluid QF _; 'on" Chromosorg G-AW-DMCS "(available from Merck AG, Darmstadt); Carrier gas flow: 20 ml / min nitrogen; Temperature progression: 80 to 250 ° C with 2 ° C per minute gradient; Sample volume: 0.2 pl.

Claims (11)

1. Process for the manufacture of secondary aliphatic amines from aliphatic nitriles and aliphatic alcohols in the liquid phase by passing hydrogen through the reaction mixture in the presence of hydrogenation/dehydrogenation catalysts at elevated temperatures and with removal of the water of reaction, which is characterized by bringing aliphatic alcohols of the formula

in which R₁ denotes a straight-chain or branched, but in the a-position at most singly branched, alkyl, alkenyl or ethylenically multi-unsaturated hydrocarbon radical having 8 to 26 C atoms or an alkoxyalkyl radical of the formula R₂(OX)_m- with a molecular weight of at least 130, in which R₂ is a straight-chain or branched alkyl, alkenyl or ethylenically multi-unsaturated hydrocarbon radical having 1 to 26 C atoms, X is a radical ―CH₂CH₂―, -CH(CH3)-CHZ or --CH₂-CH(CH₃)- and m is an integer or fraction between 1 and 20 and, within m, combinations of the radicals X can be present, or mixtures of such alcohols into intimate contact, at temperatures of 120 to 260°C and under conditions of virtually atmospheric pressure, with aliphatic nitriles of the formula

in which R₃ denotes a straight-chain or branched alkyl, alkenyl or ethylenically multi-unsaturated hydrocarbon radical having 8 to 26 C atoms or a radical of an ether-nitrile of the formula R₄―(OX)_n―O(CH₂)_p― with a molecular weight of at least 130, in which R₄ is a straight-chain or branched alkyl, alkenyl or ethylenically multi-unsaturated hydrocarbon radical having 1 to 26 C atoms, X is a radical as defined above, n is an integer or fraction between 1 and 20, or zero, and p is 1 or 3 and, within n, combinations of the radicals X can also be present, or with mixtures of such nitriles, in a molar ratio of alcohol : nitrile of 90 : 10 to 10 : 90, and with at least 2 moles of hydrogen per mole of nitrile, whereby maintaining an ammonia concentration of between 3 and 75% by volume in the reaction gas during the entire reaction time.

2. A process according to claim 1, characterized by maintaining an ammonia concentration of between 3 and 60% by volume in the reaction gas during the entire reaction time.

3. A process according to claim 1, characterized by maintaining an ammonia concentration of between 3 and 50% by volume in the reaction gas during the entire reaction time.

4. A process according to claim 2, wherein the molar ratio of alcohol : nitrile is 70 : 30 and 30:70.

5. A process according to claims 2 and 3, wherein the molar ratio of alcohol : nitrile is 60 : 40 to 40: 60.

6. A process according to claims 1 to 5, characterized by cycling the reaction gas, which consists of hydrogen and ammonia and optionally can additionally contain 0 to 50% by volume of inert gas, and removing the water of reaction from the cycle.

7. A process according to claim 6,which is characterized by removing, in the course of the reaction, part of the circulating gas batchwise or continuously from the cycle and replacing it with fresh reaction gas, optionally with the addition of inert gas.

8. A process according to claims 1 to 7, which is characterized by supplying at least part of the ammonia required to maintain the ammonia concentration from outside into the cycle.

9. A process according to claims 1 to 8, which is characterized by using starting alcohols and starting nitriles having a straight-chain or branched alkyl, alkenyl or ethylenically multi-unsaturated hydrocarbon radical having 16 to 22 C atoms.

10. A process according to claims 1 to 8, which is characterized by using alcohols containing the said alkoxyalkyl radical, and ether-nitriles, in which m is 1 to 3 and n is 1 to 3.

11. A process according to claims 1 to 10, which is characterized by using mono- or multi-unsaturated alcohols and nitriles and, after the formation of the secondary amine is completed, bringing pure hydrogen into intimate contact with the liquid phase, the pressure optionally being increased to about 4 to 10 bars.