GB1585480A

GB1585480A - Production of tertiary amines

Info

Publication number: GB1585480A
Application number: GB20169/77A
Authority: GB
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1976-05-14
Filing date: 1977-05-13
Publication date: 1981-03-04
Also published as: NL188523C; FR2351088B1; IT1075550B; FR2351088A1; BE530219A; NL188523B; NL7705277A

Description

(54) PRODUCTION OF TERTIARY AMINES (71) We, BASF AKTIENGESELL SCHAFT, a German Joint Stock Company of 6700 Ludwigshafen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement: The present invention relates to the production of tertiary amines.

The catalytic alkylation of amines with alcohols has been disclosed. On the one hand, dehydrating oxides, e.g. those of aluminum, thorium, tungsten and chromium, are used as catalysts in this reaction; on the other hand, hydrogenation or dehydrogenation catalysts, e.g. those based on copper, nickel or cobalt, have been recommended. Processes to be carried out in liquid and in gaseous phase have been proposed. A detailed description of this field is given in the article by V. A. Nekrasova and N. J. Shuikin in the periodical Russian Chemicals Reviews, 34 (1965) 843, and in the book "The Acyclic Aliphatic Tertiary Amines" by L. Spialter and J. A.

Pappalardo, The Macmillan Co., N.Y., 1965.

The production of tertiary amines by alkylating primary amines with alcohols is particularly difficult. As a result of transalkylation reactions there are formed secondary and the most varied mixed tertiary amines as by-products, which are very difficult to separate from the desired reaction products.

Further, R. G. Rice et al described, in J.

org. Chem. 23 (1958) 1352, the attempt to alkylate monobutylamine with ethyl alcohol in the liquid phase at reflux temperature using Raney nickel as catalyst. However, the reaction product obtained is not diethylbutylamine but ethyldibutylamine. It is further reported that in the reaction of butylamine with propanol-1 in the presence of Raney nickel, only (secondary) propylbutylamine is formed. It appears that this course of the reaction also underlies the proposals, made in U.S. Patent 3,223,734, to produce a tertiary amine from hydrogenated tallow alcohol and methylamine, using suspended Raney nickel as catalyst, in a two-step process (cf. Example XVIII of the said U.S. patent). The first step consists in reacting the alcohol with methylamine, at a relatively low temperature (150 to 2000C), to form mono(hydrogenated tallow)methyl amine.In the second step alkylation is continued at 200 to 2300C so that the desired di(hydtogenated tallow)methyl amine is formed. Even under these drastic reaction conditions the proportion of tertiary amines found is only 79% although the reaction mixture still contains unreacted alcohol.

Example XVI of the same patent describes the preparation of di(hydrogenated tallow)methyl amine by alkylation of di(hydrogenated tallow)amine with methanol in the presence of suspended Raney nickel. Here again, the result is unsatisfactory; only 71% of tertiary amines are found in the reaction mixture, although temperatures of up to 2130C are used.

An improved process for the production of tertiary amines is disclosed in U.S. Patent 3,366,087. In this process an at least stoichiometric amount of a secondary amine is reacted with the alcohol. It is expressly stated that the amine to be reacted should be present in the reaction zone in an at least equimolar amount with respect to the alcohol. It is shown that the use of an excess of alcohol results in poor selectivity as regards the tertiary amines formed. It appears that in the reaction of secondary alcohols a certain im- provement in amine selectivity is achieved by this measure, but the degree of conversion of the amine is low. At any rate, in the case of primary alcohols low conversions and poor selectivity are observed.Byproducts are oh- tained in the form of residues, by which the yield is diminished.

The present invention seeks to provide a process for the production of aliphatic and/or cycloaliphatic tertiary amines under conditions under which where is achieved a high yield of the desired product, which should contain as small an amount of primary and secondary amines as possible. The process should be technically simple to carry out, i.e.

in a single step. Moreover, the conversion of the alcohols should be as complete as possible, since in many cases separation of the alcohols from the amines formed is difficult because of the insufficient differences in boiling point. Another point to be observed is that separation of the alcohols by distillation increases production costs due to unnecessarily high energy consumption. Finally, the formation of residues and higher molecular weight condensation products should be avoided as far as possible, since these high molecular weight products cannot readily be separated from the catalyst.

In accordance with this invention there is provided a process for the production of a symmetrical or unsymmetrical, monofunctional or polyfunctional, tertiary amine, which includes progressively adding a primary or secondary amine of the general formula R1-NH-R2, where R1 and R2 are identical or different aliphatic or alicyclic hydrocarbon radicals optionally substituted by one or more substituents which are inert under the reaction conditions and/or one or more amino groups of the formula -NHR1, and where R1 may additionally be hydrogen, to a liquid phase comprising a primary or secondary monohydric or polyhydric alcohol, especially an alcohol containing 8 or more carbon atoms which is (or behave like) a fatty alcohol, in the presence of a catalyst having hydrogenating/dehydrogenating properties and including an inorganic base, and in the presence or absence of hydrogen, at the rate at which it reacts with the alcohol, and removing water at the rate at which it is formed.

The radicals R1 and R2 may be alkyl or cycloalkyl radicals of up ot 25 carbon atoms.

The progressive addition of the amine to the liquid phase as the reaction proceeds has the effect that the reactants, i.e. the alcohol and the amine, are contacted in such a way that over at least the main part of the reaction the amine is present in a far less than the stoichiometric amount and the alcohol essentially forms the liquid phase, and this gives rise to advantageous results. Accordingly, the liquid phase contains the alcohol in a high molar excess, is any case at the beginning of the reaction, and simultaneously contains the hydrogenation/dehydrogenation catalyst which has been additionally activated by the inclusion of an inorganic base.The amine to be reacted is added to the reaction mixture (i.e. the liquid phase including any dissolved components) so that a concentration of 10% by weight in the reaction mixture is not exceeded, averaged over the duration of the reaction.

A simple way to achieve these conditions is to contact the amine to be reacted in gaseous form with the liquid reaction mixture, starting with a liquid reaction mixture which does not contain any amine but only alcohol as reactant and already has a temperature which ensures that the reaction sets in immediately.

It is also possible to add the amine to be reacted in liquid form, e.g. by means of a metering device; the use of this method suggests itself when the reaction temperature is above the boiling point of the amine and the reaction is carried out at constant pressure.

In this way, too, the undesired occurrence of large or even excessive quantities of amine can be prevented.

The above explanations mean that in batchwise operation the reaction is carried out with gradual addition of the amine until the also hol is used up and that the desired amine can be separated from the liquid reaction mixture by distillation. In continuous operation the amine to be reacted is, for example, passed in gaseous form countercurrently to the liquid reaction mixture containing the alcohol and possibly the tertiary amine, an after-reaction zone being provided if necessary.

A feature of the invention is the continuous removal, from the reaction mixture, of the water of reaction formed at the rate at which it is formed; that is to say, either reaction conditions are maintained under which the water formed escapes from the reaction mixture in vaporous form, or the water is continuously separated outside the reaction zone and the dewatered reaction mixture is recycled.

For a better understanding of the process conditions chosen for the present process the following should be borne in mind. If the reaction were carried out in the gas phase, a very high reaction temperature would have to be chosen since in general the alcohols are relatively difficultly volatile. In that case a lower yield and impure products would be obtained. If, on the other hand, the reaction were carried out in liquid phase and using for example a pressure which is too high in view of the temperature used and too high a concentration of amine, the course of the reaction would be highly unspecific. The correctness of these deliberations is confirmed by the findings described by R. G. Rice et al in the literature reference indicated above, the said authors having used a high amine concentration.The formation of water, which usually increases with the conversion, is also detrimental; this detrimental effect is prevented by the invention.

In accordance with the invention an inorganic base, especially a small amount, e.g.

0.01 to 10%, preferably 0.01 to 5%, by weight based on the reaction mixture, of a base derived from an alkali metal or alkaline earth metal, is included in' the reaction mixture as part of the catalyst. Examples of such bases are: NaOH, LiOH, KOH, Na2O, K2O, Na2CO,, NaHCO,, Ca(OH)2 and CaO. It is of course possible to use several of these compounds at the same time. Alkali metal carbonates are preferred. The base may be used in solid, powdered form or in the form of solutions together with the dehydrogenation/hydrogenation catalysts. The coemployment of the inorganic base results in a significant activation of the catalysts. It is therefore possible to carry out the alkylation of the amines at much lower temperatures.This in turn results in the reactions proceeding with high selectivity. Since the conventional reaction temperature can be lowered by about 500C, transalkylation reactions are reduced to a minimum.

Although the reaction can be carried out in the absence of hydrogen, which according to the gross equation does not take part in the reaction, it has proved advantageous in some cases to ensure that a small quantity of hydrogen is present in the reaction zone.

However, for economic reasons the use of hydrogen will usually be dispensed with. The alkalinized catalysts are of advantage in this embodiment, too.

In principle all conventional hydrogena tion/dehydrogenation catalysts are suitable for the reaction according to the invention; how ever, particularly good results are achieved with nickel catalysts, in conjunction with an inorganic base as indicated above. Specific examples are Raney nickel on aluminium oxide, nickel on pumice, and nickel on mag nesium oxide. Good results are also achieved with catalysts based on chromium and copper, Although noble-metal catalysts based on platinum or palladium are suitable, they will usually not be employed in view of their high cost. The catalysts, especially the nickel catalysts, are used in catalytically effective amounts, e.g. 0.1 to 100%, preferably 5 to 40%, by weight based on the amount of alcohol initially present. The catalysts are not consumed in the reaction and can be reused many times.For this reason the use of larger quantities (higher concentrations) can in fact be economical in some cases.

Alcohols which can be reacted with the primary or secondary amine by the process of, the invention comprise primary and sec ondary alcohols of any type. It appears that primary alcohols can be reacted by the new process with particular advantags. The economically most important results are obtained with monofunctional and polyfunctional primary and secondary alcohols which contain 8 or more carbon atoms in the molecule, although the process works equally well with, for example, methanol, i.e. with alcohols containing 1 or more carbon atoms. Products of particular industrial importance are the fatty amines and they are derived from fatty alcohols having up to 22 carbon atoms. Specific examples are n-octyl alcohol, iso-octyl alcohol, n-decyl alcohol, isodecyl alcohol, tridecyl alcohol, stearyl alcohol, ethylene glycol, diethylene glycol, and butanediol-1,4.When polyfunctional alcohols are used, high molecular weight polycondensation products are of course formed; when high polymers bearing alcoholic hydroxyl groups are used, polyamines are formed in a reaction analogous to polymerization.

Primary amines suitable for a process according to the invention have the general formula H,NR, where R denotes any aliphatic or alicyclic radical. e.g. one having 1 to 25, particularly 1 to 10, and preferably 1 to 3 carbon atoms. Examples of industrially important primary amines are monomethylamine, Smonoethylamine and monopropylam ine; od corresponding importance are the tertiary amines obtainable therefrom.

The reaction is successful at temperatures of from 60 to 2000C, preferably from 100 to 1600C. It may be carried out at sum atmospheric or atmospheric pressure, depending on the nature of the reactants used and on the reaction temperature chosen; pressures of 2 bars or below are preferred. In some cases subatmospheric pressure may be erriployed, especially in the case of high molecular weight reactants, in order to remove the water.

If a high-boiling alcohol, such as hexanol or octanol, is used for alkylation, it suffices to heat the alcohol and, in the presence of the catalyst and alkali, to introduce the primary amine at the rate at which it is reacted with the alcohol. The water formed in the reaction is continuously distilled off from the reaction system. This later process can be promoted by removing the water of reaction as an azeotrope with a suitable solvent, e.g.

an aliphatic or aromatic hydrocarbon, and separating the azeotrope into its components.

A reaction zone suitable for the process of the invention is, for example, a reactor equipped with a stirrer, a condenser, and a water separator.

A particularly simple method consists in allowing the amine and, if appropriate, hydro gen to bubble in gaseous form through the alcohol which has been heated to the reaction temperature. In this method the water formed is removed in vapour form from the reaction zone and condensed and the non-consumed gas is recycled.

Depending on the quantity of catalyst used it is possible for example to introduce 0.05 to 0.5 mole, preferably 0.1 to 0.5 mole, of amine per mole of alcohol per hour into the reaction mixture. The quantity of hydrogen to be used is in the same order of magnitude, but may be varied within wide limits, since hydrogen is not consumed. In some cases the use of hydrogen may be dispensed with.

It may be seen from the above that it is advantageous to choose conditions under which the reaction takes about 1 to 10 hours, although shorter or longer reaction times are also possible. The rate of reaction is od course also governed by the quantity of amine added per unit time.

Is accordance with the invention the reaction can be carried out at lower temperatures than have usually been deemed possible in connection with the alkylation of primary and secondary amines with alcohols. As has been stated above, temperatures of below 1000C may be used in the reaction according to the invention without difficulty. The upper temperature limit at which the reaction can still be carried out with high selectivity is, in general, 170 C; beyond this limit, operation with satisfactory selectivity is possible in many cases. Temperatures between 100 and 1600C are preferred.

Since it is highly desirable to react the alcohol completely, the total amount of amine, added gradually, is usually the stoichiometric quantity. Towards the end d the reaction even a certain excess of amine may be advantageous, and processes in which this occurs are within the invention. The expression "towards the end of the reaction means the point at which the conversion of the alcohol used exceeds 90%. The excess may be, on an average, between 5 and 100 mole%, preferably 10 to 30 mole%, of the unreacted remainder of alcohol; that is to say, the reaction conditions are maintained until the desired conversion can be expected to have been reached. In some cases it has proved advantageous to add to the amine a small quantity of hydrogen, e.g. 5 to 20 mole%, in this final phase of the reaction.The excess if amine added is then removed from the reaction mixture. It is important that the amine should be added, in the course of the main part of the reaction, at the rate at which it reacts; this ensures that the amine always comes into contact with an excess of alcohol, in any case as long as the latter is present in the reaction mixture in any appreciable concentration. These conditions are achieved in a very simple way by using a countercurrent process, which has the additional advantage that it can be carried out continuously.

The parts and percentage indicated in the following Examples are by weight, unless otherwise stated. Parts by weight bear the same relation to parts by volume as the kilo gramm to the litre.

EXAMPLE 1.

744 parts of n-dodecanol, 400 parts of Raney nickel and 10 parts of anhydrous sodium carbonate are pllaced in a stirred vessel at atmospheric pressure and the mixture is heated to 1SOOC. During the heating-up period such an amount of monomethylamine is introduced in gaseous form that the reaction mixture is saturated.

The reaction sets in at above 1 100C and an aqueous phase is separated in a distillation head designed for azeotropic water removal.

Then 35 parts per hour of monomethylamine are fed into the reaction mixture in gaseous form. From the distillation head about 18 to 19 parts per hour of aqueous phase are o tained. The reaction is over after 4 hours; the separation of water has ceased.

After cooling, the reaction product is sep; arated from the catalyst by filtration and the colourless filtrate is worked up by distillation.

A small quantity of a mixture of 40% of dimethyllaurylamine and 60% of methyllaurylamine (15% of the total quantity calculated from e conversion; bpl = 80 to 1000 C) is obtained as first runnings. At a boiling point of 1400C and a pressure of 10-6 mbars, dilaurylmethylamine is obtained (75 % of the total amount calculated from the conversion); trilaurylamine (5%) remains as a non-distill- able residue.

A similar result is obtained when using potassium carbonate as a catalyst addition.

When sodium bicarbonate and potassium bicarbonate are employed, the rate of reaction is increased by about 30%, while the yield remains essentially unchanged.

While an addition of 10 parts of calcium oxide increases the rate of reaction by about 10% as compared with sodium carbonate, the addition of 10 parts of calcium hydroxide, 10 parts of barium hydroxide or 0.5 part of sodium hydroxide lowers it by about 20%.

If Raney cobalt is used instead of Raney nickel, the process is, in principle, also successful. However, under comparable reaction conditions a conversion of only 15 % is achieved.

A similar result is obtained if stearyl alcohol is used for alkylating the monomethylamine at 1600C. The desired distearylmethylamine is obtained in a yield of 78%.

A 65 % yield is obtained if the alcohol used is an isomer mixture called isotridecanol which can be prepared from trimeric propylene by the oxosynthesis.

EXAMPLE 2.

The procedure described in Example 1 is followed. A suspension of 100 parts of a nickel catalyst, prereduced at 3700C with hydrogen and containing 45% of nickel on magnesium silicate, and 7 parts of sodium carbonate in 390 parts of n-octanol-l is heated to 1500C and then gaseous monoethylamine is introduced into the well-stirred suspension at this temperature. After 7 hours the reaction is over. Working up by distillation gave the following products, the percentages being based on the quantity of alcohol reacted: 82% of dioctylethylamine (bpl 3 = 150 C) 10% of a mixture consisting essentially of octylethylamine and diethyloctylamine in a ratio of 3 : 2 (bop22 = 116 to 1250C) 3% of trioctylamine.

EXAMPLE 3.

For carrying out a process in continuous operation a vertically arranged reaction tube is filled with 2,000 parts by volume of a catalyst composition consisting of 57% of nickel oxide, 16% of magnesium oxide, 23% of SiO2, 1% of Cr2O3 and 3% of Na2CO,, which can be referred to as a magnesium silicate supported catalyst. The catalyst composition is in the form of cylindrical pellets 3 mm in diameter and 3 mm in length. The ratio of diameter to length of the reaction tube is 1 : 20. Before the reaction is started, the catalyst is activated by heating at 3700C in a stream of hydrogen.

At 1550C, 200 parts by weight of n-dode canol-l are introduced per hour at the top of the reaction tube. About 33 parts by weight of gaseous monomethylamine are supplied per hour to the bottom of the reaction tube. Unreacted monomethylamine, which escapes at the upper end of the reaction tube, is freed from the entrained water vapour and recycled to the reaction tube by means of a pump.

As monomethylamine is consumed, makeup is added continuously. At the lower end of the reaction tube about 185 parts by weight per hour of a mixture of amines is withdrawn.

This mixture consists of about 70% of dilaurylethylamine, 20% of methyllaurylamine, 8% of dimethyllaurylamine and 2% O/o of trilaurylamine.

EXAMPLE 4.

744 kg of n-dodecanol-l (lauryl alcohol), 500 kg of ethylbenzene, 10 kg of sodium carbonate and 300 kg of Raney nickel are placed in a stirred vessel operated at atmospheric pressure and the mixture is heated to 130 to 1350C. As soon as this temperature has been reached, hydrogen and dimethylamine are passed into the reaction mixture.

In a distillation head designed for azeotropic water removal, ethylbenzene and a lower aqueous phase are separated. The ethylben zene is recycled. After a reaction time of 7 hours the calculated amount of water has been separated; the reaction ceases. The reaction product is separated from the catalyst by filtration and the colourless filtrate is distilled.

The original quantity of ethylbenzene and, at a pressure of 1.3 mbars and a temperature of about 800C, pure dimethyllaurylamine (80% of the calculated amount), which is free from secondary and primary amines, are obtained. At a boiling point of 1480C and a pressure of 10-4 mbars pure dilaurylmethylamine, which is free from primary and secondary amines, is obtained (15% of the calculated amount). The residue obtained consists mainly of trilaurylamine (5 % of the calculated amount).

The same result is obtained if potash is used instead of soda ash. If sodium bicarbonate is used the rate of reaction is increased by about 30%, the yields obtained being the same as with sodium carbonate. If the process is carried out at 1200C in the absence of hydrogen and ethylbenzene, dimethyllaurylamine in a yield of 92% is obtained within a reaction time of 7 hours.

If Raney cobalt is used as catalyst instead of Raney nickel, the reaction also takes place; however, the rate of reaction is only 1/20 of that observed when using Raney nickel under comparable conditions.

EXAMPLE 5.

The procedure of Example 1 is followed except that dodecanol is replaced by noctanol-l. There are obtained 75% of the calculated amount of dimethyloctylamine, 15 % of dioctylmethylamine and 10% of trioctylamine, based on the alcohol. The reaction to form the tertiary amine proceeds almost quantitatively as in the case of alkylation with lauryl alcohol.

EXAMPLE 6.

The equipment described in Example 4 is used. For the production of diethyloctylamine, 390 kg of n-octanol and 300 kg of ethylbenzene are heated to 1350C in the presence of 150 kg of Raney nickel and 10 kg of calcined ground soda ash. In the course of 8 hours 230 kg of diethylamine are added to the reaction mixture while stirring well. The water being formed is continuously withdrawn in the manner described. Upon completion of the reaction the mixture is distilled; there is obtained 85 % of diethyloctylamine (boiling point 980C at 13 mbars), 9% of dioctylethylamine (boiling point 1160C at 1.3 mbars), and 6% of trioctylamine (in each case based on the quantity of the substance used in a less than stoichiometric amount).

Here again, the reaction products are free from primary and secondary amines.

A similar result is obtained when a finely ground nickel catalyst containing 70% of nickel on magnesium silicate and reduced at 3700C prior to use is employed instead of Raney nickel.

The catalysts separated from the finished reaction product by filtration can be reused for the reaction and do not exhibit any decrease in activity even after having been reused 30 times.

EXAMPLE 7.

644 kg of ethanol (100 mole% excess), 315 kg of dimethylamine, 200 kg of Raney nickel and 10 kg of calcined ground soda ash were heated at 1600C for 12 hours in a pressure-tight stirred vessel at a hydrogen pressure of 20 bars. Upon cooling, the reaction mixture is freed from catalyst and separated by distillation. There is obtained 55 mole% of dimethylethylamine (boiling point 350), 43 mole % of diethylmethylamine (boiling point 630C) and 2 mole% of triethylamine, based on alcohol reacted.

EXAMPLE 8.

In an apparatus similar to, but smaller than, that described in Example 4, 390 parts of n-octanol-1, 300 parts of ethylbenzene, 20 parts of bis-(cycloocta-1,5-dienyl)-nickel(0) and 10 parts of calcined ground soda ash are heated to 1350C while introducing steam.

After the reaction temperature has been reached, 218 parts of diethylamine are added to the reaction mixture uniformly over 15 hours with vigorous stirring. A black metallic nickel precipitate separates. At the same time water is formed which is removed from the reaction mixture as an azeotrope by distillation with ethylbenzene. The reaction product obtained is separated into its constituents by distillation, but is first distilled off from the catalyst at 1.3 mbars and a bottoms temperature of up to 1200 C. 140 parts of distillate is obtained, which is fractionally distilled in a packed column (5 theoretical trays) at 13 and 1.3 mbars. There is obtained 83% of the caculated amount of diethyloctylamine (bp = 980 C) and 10% of dioctylethylamine (bop,.3 = 1160C).About 3% by weight of the crude distillate remain as residue.

EXAMPLE 9.

The procedure described in Example 6 is followed except that use is made of a catalyst containing 20% of copper on silica, prereduced at 1800C with hydrogen and ground in a ball mill in octanol for 5 hours. After 18 hours the reaction of n-octanol to give diethyloctylamine is complete. Gas chromatographic analysis shows that the reaction mixture contains 86% of the calculated amount of diethyloctylamine, 7% of dioctylethylamine and 7% of trioctylamine.

EXAMPLE 10.

Using the apparatus described in Example 4, 2,500 kg of a C,,--C,, oxoalcohol mixture prepared from a C12,4 Ziegler olefin, 300 kg of Raney nickel.and 25 kg of calcium oxide are reacted with dimethylamine at 1380C and atmospheric pressure under a hydrogen blanket. After 25 hours, reaction of the quantity of dimethylamine which is expected to react is over. 215 kg of water are formed during the reaction. After separation of the catalyst by filtration there remains a colourless mixture of tertiary amines having an amine number of 200 mg of KOH/g.

The alcohol used consists of about 70% of tridecanol and 30% of pentadecanol. The amine number calculated for a dimethylalkylamine obtainable therefrom is 239 mg of KOH/g. Practically the same result is obtained when the calcium oxide is replaced by 25 kg of barium oxide, 20 kg of calcium hydroxide or 1.3 kg of potassium hydroxide.

EXAMPLE 11.

Following the procedure described in Example 4, a solution of 400 parts of cyclohexanol and 353 parts of ethylbenzene is reacted with dimethylamine in the presence of 200 parts of Raney nickel and a mixture of 5 parts of sodium carbonate and 10 parts of calcium carbonate at 1300C in the presence of hydrogen. After 24 hours the reaction is over. The reaction mixture is freed from catalyst by filtration and the dimethylcyclohexylarnine formed is separated by distillation.

The yield is 380 parts (75 /O of theory). The amine number of the product is 488 mg of KOH/g; its boiling point at 30 mbars is 570C.

EXAMPLE 12.

848 parts of diethyleneglycol, 350 parts of Raney nickel and 10 parts of sodium carbonate are placed in a stirred vessel operated at atmospheric pressure and equipped with a dephlegmator which is operated at 1000C; no hydrogen blanket is used. In the course of 20 hours 900 parts of dimethylamine are introduced into the well-stirred reaction mixture at 1400C. During this time 600 parts of condensate are obtained in a cooled receiver connected to the dephlegmator. This condensate is combined with the reaction solution freed from catalyst by filtration, and worked up by the distillation. There are obtained 420 parts of bis- [2-(N,N-dimethylamino)ethyl] ether (bp1, = 700C, yield 52% of theory) and 240 parts (18% of theory) of 2-[2-(N,N-dimethyl- amino)ethoxy] ethanol (bpia =' 880C). 150 parts of distillation bottoms remain as residue., When the 2- [2-(N,Ndimethylamino)- ethoxy] ethanol is again reacted with dimethylamine under the reaction conditions described above, 40% of the substance is converted into is- [2-(N,N-dimethylamino)-ethyl] ether.

EXAMPLE 13.

1,000 parts of polytetramethylene ether glycol-a polytetrahydrofuran which is obtainable for example from Quaker Oats under the designation Polymeg 65eare reacted, in the apparatus described in Example 9, with dimethylamine in the presence of 300 parts of Raney nickel and 15 parts of sodium bicarbonate, at atmospheric pressure and without the use of a hydrogen blanket. The polytetrahydrofuran has an OH number of 174 mg of KOH/g, which corresponds to a molecular weight of 645. After 10 hours the reaction is over. During this time 53 parts of water is formed. The colourless reaction product, freed from catalyst by filtration, has an amino number of 123 mg of KOH/g.

EXAMPLE 14.

744 parts of n-dodecanol-l, 500 parts of ethylbenzene, 10 parts of sodium carbonate and 300 parts of Raney nickel are placed in a stirred vessel as described in Example 4, and heated to 1350C. During the heating-up period the reaction mixture is kept saturated with hydrogen and dimethylamine. The reaction commences at above 1100C and an aqueous phase is obtained in a distillation head designed for azeotropic water removal.

Then 28 parts of dimethylamine and 15 parts by volume (S.T.P.) of hydrogen are introduced per hour into the reaction mixture in gaseous form. At the reaction temperature the mixture boils, the ethylbenzene being distilled off together with the water of reaction. The aqueous phase is separated in a water separator and the solvent is returned to the reactor.

After 7 hours the reaction is over; the separation of water has ceased. After cooling, the reaction product is separated from the catalyst by filtration and the colourless filtrate is worked up by distillation. The original quantity of ethylbenzene is obtained as first runnings; subsequent distillation at subatmospheric pressure gives dimethyllaurylamine (80% of the calculated amount; bpl = 800C). At a boiling point of 1480C and a pressure of 10-4 mbars dilaurylmethylantine (15 % of the calculated amount) is obtained. Trilaurylamine (5% of the calculated amount) remains as a residue.

A similar result is obtained when using potassium carbonate as catalyst addition. An about 30% /O higher reaction rate can be achieved by using sodium bicarbonate and potassium bicarbonate. In this case the yield of pure dimethyllaurylamine is about 85%.

A slightly (about 20%) reduced rate of reaction is achieved by addition of 10 parts of calcium hydroxide, 10 parts of barium hydroxide or 0.5 part of potassium hydroxide. If Raney cobalt is used instead of Raney nickel, the process is, in principle, also successful as regards product purity; however, the rate of reaction is only about 1/20 of that achieved with Raney nickel. When the process is carried out with n-octanol-l instead of with dodecanol under the same reaction conditions, there are formed about 80% of the calculated amount of dimethyloctylamine, 15 % of di octylmethylamine and 5% of trioctylamine, based on the alcohol. There is practically no formation of secondary and primary amines.

An approximately equally good result is obtained when the alcohol used is isotridecanol prepared from trimeric propylene by oxosynthesis.

EXAMPLE 15.

The procedure described in Example 14 is followed. 390 parts of n-octanol-l, 150 parts of Raney nickel, 300 parts of ethylbenzene and 10 parts of calcined ground soda ash are heated to 1350C while introducing hydrogen.

As soon as the reaction temperature has been reached, a total of 218 parts of gaseous diethylamine is added to the reaction mixture uniformly over 8 hours with vigorous stirring.

The water formed is removed as an azeotrope by distillation of ethylbenzene. The reaction mixture is worked up as described above, the following reaction products being isolated: 85 % of theory of diethyloctylamine (bp13 = 980C) 9% of theory of dioctylethylamine (bpl., = 1160C) 6% of theory of trioctylamine The amines obtained are free from primary and secondary groupings.

As compared with the last-mentioned reaction time, the reaction is accelerated by about 40% when using, instead of Raney nickel, a catalyst consisting of 45% of nickel on magnesium silicate and prereduced with hydrogen at 3700C.

If the reactions are carried out with starting materials which are free from catalyst poisons, the catalyst have an almost unlimited life. The reaction of n-octanol-l with dimethylamine was carried out with Raney nickel 30 times without any decrease in activity or selectivity being observed.

EXAMPLE 16.

Dimethylarnine is reacted with n-dodeca nol-l in accordance with the procedure of Example 4 and in the apparatus described therein, but the use of hydrogen and solvent is dispensed with. The reaction temperature is 1180C. After 10 hours complete reaction of the alcohol has been achieved. Subsequent working up of the reaction mixture by distillation gives 90% of the calculated amount of dimethyllaurylamine, 8% of dilaurylmethylamine and 2% of trilaurylamine.

EXAMPLE 17.

For carrying out a continuous process, a vertically arranged reaction tube is filled with 2,000 parts by volume of a catalyst composition which, according to analysis, consists of 57% of NiO, 16% of MgO, 23% of SiO2, 1% of Cur203 and 3% of Na2CO8 and may be referred to as a magnesium silicate supported catalyst. The catalyst is in the form of cylindrical pellets 3 mm in diameter and 3 mm in length. The ratio of diameter to length of the reaction tube is 1 : 20. Before the reaction is started the catalyst is activated by heating at 300 to 3700C in a stream of hydrogen.

At 900C, 200 parts by weight of n-dodecanol-1 are introduced per hour at the top of the reaction tube. About 90 parts by weight of gaseous dimethylamine are supplied per hour to the bottom of the reaction tube. Unreacted dimethylamine, which escapes at the upper end of the reaction tube, is freed from the entrained water vapour and recycled to the reaction tube by means of a pump. As dimethylamine is consumed, makeup is added continuously. At the lower end of the reaction tube about 230 parts by weight per hour of a mixture of amines is withdrawn. This mixture consists of about 90% of dimethyllaurylamine, 6% of dilaurylmethylamine and 4% of trilaurylamine.

WHAT WE CLAIM IS: 1. A process for the production of a monofunctional or polyfunctional, symmetrical or unsymmetrical, tertiary amine which includes progressively adding a primary or secondary amine of the formula R1-NH-R' where R1 and Ri are identical or different aliphatic or alicyclic hydrocarbon radicals optionally substituted by one or more amino groups of the formula -NHR1 and/or one or more substituents which are inert under the reaction conditions and R1 may additionally be hydrogen, to a liquid phase comprising a primary or secondary, monohydric or polyhydric alcohol in the presence of a catalyst having hydrogenating/dehydrogenating properties and including an inorganic base, and in the presence or absence of hydrogen, at the rate at which it reacts with the alcohol, and removing water at the rate at which it is formed.

2. A process as claimed in claim 1, wherein the amine to be reacted is added to the liquid phase at such a rate that, averaged over the duration of the reaction, a concentration of 10 % by weight in the mixture is not exceeded.

3. A process as claimed in claim 1 or 2, wherein the amine to be reacted is contacted in gaseous form with the liquid phase which initially does not contain any amine.

4. A process as claimed in claim 3, wherein gaseous amine is passed continuously countercurrently to the liquid phase.

5. A process as claimed in claim 1 or 2, wherein the amine to be reacted is added in liquid form to the liquid phase by means of a metering device.

6. A process as claimed in any of claims 1 to 5, wherein the reaction is carried out at a temperature from 60 to 200cm.

7. A process as claimed in any of claims 1 to 6, wherein the reaction is carried out at a pressure of 2 bars or less.

8. A process as claimed in any of claims 1 to 7, wherein the reaction is carried out such that the water formed continuously escapes in vaporous form from the zone in which reaction occurs.

9. A process as claimed in any of claims 1 to 7, wherein the reaction is carried out such that water is continuously separated from the other components outside the zone in which reaction occurs and the other components are recycled to the reaction zone.

10. A process as claimed in any of claims 1 to 9, wherein the catalyst is a nickel catalyst together with an inorganic base and the proW cess is carried out at a temperature of from 100 to 1600C.

11. A process as claimed in claim 9, wherein the catalyst is Raney nickel suspended in the reaction mixture in the presence od a susr pended inorganic base.

12. A process as daimed in any of claims 1 to 11, wherein the inorganic base is an alkali metal carbonate.

13. A process as claimed in any of claims 1 to 12, wherein from 0.01 to 5% by weight of inorganic base, based on the weight of liquid phase plus catalyst, is used.

14. A process as claimed in any of claims 1 to 13, wherein the amine to be reacted is a primary amme.

15. A process as claimed in any of claims 1 to 13, wherein the amine to be reacted is a secondary amine.

16. A process as claimed in any of claims 1 to 15, wherein the radicals R1 and R2 in the formula of the amine are alkyl or cycloalkyl radicals of up to 25 -carbon atoms and Rl may additionally be hydrogen.

17. A process as claimed in claim 14 or 16, wherein the amine is a primary aliphatic or cycloaliphatic amine of up to 10 carbon atoms.

18. A process as claimed in any of claims 1 to 17, wherein the alcohol contains 8 or more carbon atoms and is, or behaves like, a fatty alcohol.

19. A process for the manufacture of a tertiary amine carried out substantially as described in any of the foregoing Examples.

20. Tertiary amines when manufactured by a process as claimed in any of claims 1 to 19.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

3 mm in length. The ratio of diameter to length of the reaction tube is 1 : 20. Before the reaction is started the catalyst is activated by heating at 300 to 3700C in a stream of hydrogen.

At 900C, 200 parts by weight of n-dodecanol-1 are introduced per hour at the top of the reaction tube. About 90 parts by weight of gaseous dimethylamine are supplied per hour to the bottom of the reaction tube. Unreacted dimethylamine, which escapes at the upper end of the reaction tube, is freed from the entrained water vapour and recycled to the reaction tube by means of a pump. As dimethylamine is consumed, makeup is added continuously. At the lower end of the reaction tube about 230 parts by weight per hour of a mixture of amines is withdrawn. This mixture consists of about 90% of dimethyllaurylamine, 6% of dilaurylmethylamine and 4% of trilaurylamine.

WHAT WE CLAIM IS: 1. A process for the production of a monofunctional or polyfunctional, symmetrical or unsymmetrical, tertiary amine which includes progressively adding a primary or secondary amine of the formula R1-NH-R' where R1 and Ri are identical or different aliphatic or alicyclic hydrocarbon radicals optionally substituted by one or more amino groups of the formula -NHR1 and/or one or more substituents which are inert under the reaction conditions and R1 may additionally be hydrogen, to a liquid phase comprising a primary or secondary, monohydric or polyhydric alcohol in the presence of a catalyst having hydrogenating/dehydrogenating properties and including an inorganic base, and in the presence or absence of hydrogen, at the rate at which it reacts with the alcohol, and removing water at the rate at which it is formed.
2. A process as claimed in claim 1, wherein the amine to be reacted is added to the liquid phase at such a rate that, averaged over the duration of the reaction, a concentration of 10 % by weight in the mixture is not exceeded.
3. A process as claimed in claim 1 or 2, wherein the amine to be reacted is contacted in gaseous form with the liquid phase which initially does not contain any amine.
4. A process as claimed in claim 3, wherein gaseous amine is passed continuously countercurrently to the liquid phase.
5. A process as claimed in claim 1 or 2, wherein the amine to be reacted is added in liquid form to the liquid phase by means of a metering device.
6. A process as claimed in any of claims 1 to 5, wherein the reaction is carried out at a temperature from 60 to 200cm.
7. A process as claimed in any of claims 1 to 6, wherein the reaction is carried out at a pressure of 2 bars or less.
8. A process as claimed in any of claims 1 to 7, wherein the reaction is carried out such that the water formed continuously escapes in vaporous form from the zone in which reaction occurs.
9. A process as claimed in any of claims 1 to 7, wherein the reaction is carried out such that water is continuously separated from the other components outside the zone in which reaction occurs and the other components are recycled to the reaction zone.
10. A process as claimed in any of claims 1 to 9, wherein the catalyst is a nickel catalyst together with an inorganic base and the proW cess is carried out at a temperature of from 100 to 1600C.
11. A process as claimed in claim 9, wherein the catalyst is Raney nickel suspended in the reaction mixture in the presence od a susr pended inorganic base.
12. A process as daimed in any of claims 1 to 11, wherein the inorganic base is an alkali metal carbonate.
13. A process as claimed in any of claims 1 to 12, wherein from 0.01 to 5% by weight of inorganic base, based on the weight of liquid phase plus catalyst, is used.
14. A process as claimed in any of claims 1 to 13, wherein the amine to be reacted is a primary amme.
15. A process as claimed in any of claims 1 to 13, wherein the amine to be reacted is a secondary amine.
16. A process as claimed in any of claims 1 to 15, wherein the radicals R1 and R2 in the formula of the amine are alkyl or cycloalkyl radicals of up to 25 -carbon atoms and Rl may additionally be hydrogen.
17. A process as claimed in claim 14 or 16, wherein the amine is a primary aliphatic or cycloaliphatic amine of up to 10 carbon atoms.
18. A process as claimed in any of claims 1 to 17, wherein the alcohol contains 8 or more carbon atoms and is, or behaves like, a fatty alcohol.
19. A process for the manufacture of a tertiary amine carried out substantially as described in any of the foregoing Examples.
20. Tertiary amines when manufactured by a process as claimed in any of claims 1 to 19.