Process for the preparation of a mono-N-alkylpiperazine

Information

  • Patent Grant
  • 8927712
  • Patent Number
    8,927,712
  • Date Filed
    Friday, May 31, 2013
    11 years ago
  • Date Issued
    Tuesday, January 6, 2015
    10 years ago
Abstract
Process for the preparation of a mono-N-alkylpiperazine of the formula I
Description

The present invention relates to a process for the preparation of a mono-N-alkylpiperazine of the formula I




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in which R1 is C1- to C5-alkyl or 2-(2-hydroxyethoxy)ethyl, by reacting diethanolamine (DEOA) of the formula II




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with a primary amine of the formula H2N—R1 (III) in the presence of hydrogen and a catalyst molding.


The process products are used inter alia as intermediates in the production of fuel additives (U.S. Pat. No. 3,275,554 A; DE 21 25 039 A and DE 36 11 230 A), surfactants, drugs and crop protection agents, hardeners for epoxy resins, catalysts for polyurethanes, intermediates for producing quaternary ammonium compounds, plasticizers, corrosion inhibitors, synthetic resins, ion exchangers, textile auxiliaries, dyes, vulcanization accelerators and/or emulsifiers.


WO 2011/067199 A1 (BASF SE) relates to certain aluminum oxide-, copper-, nickel-, cobalt- and tin-containing catalysts and their use in processes for the preparation of an amine from a primary or secondary alcohol, aldehyde and/or ketone. The preparation of N-methylpiperazine from DEOA and monomethylamine is mentioned in general terms on page 25, lines 20-21.


WO 2011/157710 A1 (BASF SE) describes the preparation of certain cyclic tertiary methylamines, where an amino alcohol from the group 1,4-aminobutanol, 1,5-aminopentanol, aminodiglycol (ADG) or aminoethylethanolamine is reacted with methanol at elevated temperature in the presence of a copper-containing heterogeneous catalyst in the liquid phase.


WO 2012/049101 A1 (BASF SE) relates to a process for the preparation of certain cyclic tertiary amines by reacting an amino alcohol from the group 1,4-aminobutanol, 1,5-aminopentanol, aminodiglycol (ADG) or aminoethylethanolamine with a certain primary or secondary alcohol at elevated temperature in the presence of a copper-containing heterogeneous catalyst in the liquid phase.


CN 102 101 847 A (Zhangjiagang Tianyou New Material Techn. Co., Ltd.) describes a two-stage synthesis for N-methyl-N-(2-chloroethyl)piperazine from aminodiglycol (ADG) via N-methylpiperazine as intermediate.


CN 102 304 101 A (Shaoxing Xingxin Chem. Co., Ltd.) relates to the simultaneous preparation of piperazine and N-alkylpiperazines by reacting N-hydroxyethyl-1,2-ethanediamine with primary C1-7-alcohols in the presence of metallic catalysts.


EP 446 783 A2 (BASF AG) relates inter alia to the preparation of N-aryl-substituted piperazines by amination of corresponding N,N-di(2-hydroxyalkyl)-N-arylamines.


EP 235 651 A1 (BASF AG) teaches a process for the preparation of N-methylpiperazine from DEOA and methylamine in the presence of metal-containing supported catalysts, in particular Cu-containing catalysts.


DE 198 59 776 A1 (BASF AG) relates to certain amination processes using catalyst moldings which comprise oxygen-containing compounds of titanium and of copper and metallic copper.


WO 04/085356 A1 and WO 2010/115759 A2 (both BASF AG) describe the use of certain Al2O3/Cu/lanthanum oxide catalysts for the hydration of certain carbonyl compounds.


The object of the present invention was to improve the economic feasibility of processes to date for the preparation of mono-N-alkylpiperazines of the formula I and to overcome one or more disadvantages of the prior art. The aim was to find conditions which can be established in technical terms in a simple manner and which make it possible to carry out the process with high conversion, high yield, space-time yields (STY), selectivity coupled with simultaneously high mechanical stability of the catalyst molding and low “runaway risk”.


[Space-time yields are given in “amount of product/(catalyst volume·time)” (kg/(lcat.·h)) and/or “amount of product/(reactor volume·time)” (kg/(lreactor·h)].


Accordingly, a process for the preparation of a mono-N-alkylpiperazine of the formula I




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in which R1 is C1- to C5-alkyl or 2-(2-hydroxyethoxy)ethyl, by reacting diethanolamine (DEOA) of the formula II




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with a primary amine of the formula H2N—R1 (III) in the presence of hydrogen and a catalyst molding has been found, wherein the reaction is carried out in the liquid phase at an absolute pressure in the range from 150 to 250 bar and the amination is carried out by means of a catalyst molding, the precursor of which can be prepared according to a process in which


(i) an oxidic material comprising copper oxide, aluminum oxide and lanthanum oxide is provided,


(ii) pulverulent metallic copper and/or copper flakes and optionally graphite is added to the oxidic material,


(iii) the mixture resulting from ii is shaped to give a molding,


where the oxidic material is obtainable by simultaneous or successive precipitation of the component copper oxide, of the component aluminum oxide and of the component lanthanum oxide and subsequent drying and calcination


and, after the shaping according to step iii, the catalyst molding is calcined again.


The radical R1 is 2-(2-hydroxyethoxy)ethyl or C1-5-alkyl, preferably C1-3-alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, particularly preferably methyl, ethyl and 2-(2-hydroxyethoxy)ethyl.


The primary amine III is correspondingly particularly preferably monomethylamine, monoethylamine or 1-amino-2-(2-hydroxyethoxy)ethane (aminodiglycol, ADG).


Preferably preparable with the process according to the invention are amines of the formula I




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in which R1=methyl, ethyl or 2-(2-hydroxyethoxy)ethyl.


In particular, catalyst moldings are used wherein the oxidic material comprises


(a) copper oxide with a fraction in the range from 50≦x≦80% by weight, preferably 55≦x≦75% by weight, in, each case calculated as CuO,


(b) aluminum oxide with a fraction in the range from 15≦y≦35% by weight, preferably 20≦y≦30% by weight, and


(c) lanthanum oxide with a fraction in the range from 2≦z≦20% by weight, preferably 3≦z≦15% by weight, further preferably 3.5≦z≦10% by weight,


in each case based on the total weight of the oxidic material after calcination, where: 80≦x+y+z≦100, in particular 95≦x+y+z≦100.


The process can be carried out continuously or discontinuously. Preference is given to a continuous procedure.


In the circulating-gas procedure, the starting materials (DEOA, the primary amine III) are evaporated in a circulating-gas stream and passed to the reactor in gaseous form.


The starting materials (DEOA, the primary amine III) can also be evaporated as aqueous solutions and be passed with the circulating-gas stream to the catalyst bed.


Preferred reactors are tubular reactors. Examples of suitable reactors with circulating-gas stream can be found in Ullmann's Encyclopedia of Industrial Chemistry, 5th ed., vol. B 4, pages 199-238, “Fixed-Bed Reactors”.


Alternatively, the reaction takes place advantageously in a tube-bundle reactor or in a mono-stream plant.


In a mono-stream plant, the tubular reactor in which the reaction takes place can consist of a serial connection of a plurality (e.g. two or three) of individual tubular reactors. Optionally, an intermediate introduction of feed (comprising the DEOA and/or primary amine III and/or H2) and/or circulating gas and/or reactor discharge from a downstream reactor is advantageously possible here.


The circulating-gas amount is preferably in the range from 40 to 1500 m3 (at atmospheric pressure)/[m3 of catalyst (bed volume)·h], in particular in the range from 400 to 1400 m3 (at atmospheric pressure)/[m3 of catalyst (bed volume)·h]. (Atmospheric pressure=1 bar abs.).


The circulating gas comprises preferably at least 10, particularly 50 to 100, very particularly 80 to 100, % by volume of hydrogen (H2).


In preferred embodiments, the catalyst moldings are used in the process according to the invention as unsupported, impregnation, coated or precipitation catalysts.


The catalyst used in the process according to the invention for the amination is notable for the fact that the component copper oxide, the component aluminum oxide and the component lanthanum oxide are precipitated preferably with a sodium carbonate solution, simultaneously or successively, then dried, calcined, shaped, e.g. tableted, and calcined again.


Copper oxide means CuO, Cu2O or a mixture of both oxides. For quantitative data, copper(I) oxide is calculated as copper(II) oxide.


Aluminum oxide means Al2O3 and lanthanum oxide means La2O3.


In particular, the following precipitation method is contemplated:

  • A) A copper salt solution, an aluminum salt solution and a solution of a salt of lanthanum or a solution comprising copper, aluminum and lanthanum salt is simultaneously, or are successively, precipitated with a sodium carbonate solution.
  • B) Precipitation of a copper salt solution and, separately, of a solution of a salt of lanthanum or a solution comprising copper salt and a salt of lanthanum onto a prefabricated aluminum oxide support. In one particularly preferred embodiment, this is present in the form of a powder in an aqueous suspension. However, the support material can e.g. also be present as spheres, extrudates, spall or tablets.
    • In one particular variant of B) (B1), a copper salt solution and a solution of a salt of lanthanum or a solution comprising copper salt and a salt of lanthanum is precipitated preferably with sodium carbonate solution. The initial charge used is an aqueous suspension of the support material aluminum oxide.


Precipitated solids which result from A) or B) are separated off in the usual way, e.g. filtered, and preferably washed to free them from alkali, as is described, for example, in DE 198 09 418 A1 (BASF AG).


After the precipitation of the components, particularly the end products from A) or from B), these are dried at elevated temperature, particularly at temperatures of from 50 to 150° C., preferably at 110 to 130° C. (e.g. over a period from 5 to 30 hours, preferably 10 to 20 hours) and then calcined, preferably e.g. over a period from 0.5 to 6 hours, particularly 1 to 3 hours, at generally 200 to 700° C., in particular at 400 to 650° C.


The starting substances for A) and/or B) can in principle be all Cu(I) and/or Cu(II) salts soluble in the solvents used in the precipitation (preference being given to water), such as, for example, nitrates, carbonates, acetates, oxalates or ammonium complexes, and also analogous ammonium salts and salts of lanthanum. Particular preference is given to using copper (II) nitrate as copper salt. The lanthanum salt used is preferably lanthanum nitrate. The aluminum salt used is preferably aluminum nitrate.


The composition of the oxidic material is preferably such that the fraction of copper oxide is in the range from 50 to 80% by weight, particularly 55 to 75% by weight, in each case calculated as CuO, the fraction of lanthanum oxide is in the range from 2 to 20% by weight, particularly 3 to 15% by weight, and the fraction of aluminum oxide is in the range from 15 to 35% by weight, particularly 20 to 30% by weight, for all components, in each case based on the total weight of the sum of the aforementioned oxidic constituents, these three oxides together constituting at least 80% by weight, particularly at least 95% by weight, of the oxidic material after calcination, where optionally added cement, e.g. clay earth cement, is not included in the oxidic material in the above sense.


In one preferred embodiment, the present invention therefore provides a process, as described above, wherein the oxidic material comprises

  • (a) copper oxide with a fraction in the range from 50≦x≦80% by weight, preferably 55≦x≦75% by weight, in each case calculated as CuO,
  • (b) aluminum oxide with a fraction in the range from 15≦y≦35% by weight, preferably 20≦y≦30% by weight, and
  • (c) lanthanum oxide with a fraction in the range from 2≦z≦20% by weight, preferably 3≦z≦15% by weight, further preferably 3.5≦z≦10% by weight,


    in each case based on the total weight of the oxidic material after calcination, where: 80≦x+y+z≦100, in particular 95≦x+y+z≦100.


The catalysts used in the process according to the invention are also notable for the fact that the addition of the lanthanum salt during the precipitation leads to a high stability of the ultimately resulting molding which is used as catalyst.


Then (step ii), pulverulent copper and/or copper flakes and optionally graphite is/are added to the oxidic material. Preferably, pulverulent copper and graphite is added. The addition of graphite can also take place before the addition of copper, in which case then preferably a precompaction is firstly carried out. E.g. graphite is added in amounts in the range from 0 to 5% by weight, preferably in the range from 0.5 to 4% by weight, particularly preferably in the range from 0.8 to 2% by weight, in each case based on the total weight of the oxidic material after calcination.


The pulverulent copper used is preferably that which has a grain diameter in the range from 1 to 700 μm, preferably in the range from 5 to 500 μm. Particular preference is given to using a pulverulent copper in which the sieve analysis produces a fraction of particles>500 μm of ≦6%, particularly a fraction of particles>350 μm of ≦5%. The grain morphology is preferably spherical.


The copper flakes used are preferably those which have a D50 value in the range from 5 to 40 μm, particularly in the range from 10 to 35 μm (“D50 value” means that 50% of the particles are smaller than the stated value). Preferably, the sieve analysis produces a fraction of particles>45 μm of ≦6%, particularly ≦2%. The copper flakes preferably have a lamellar flake structure.


Pulverulent copper and/or copper flakes, taken together, are preferably added in amounts in the range from 0.5 to 40% by weight, preferably in the range from 2 to 20% by weight, particularly preferably in the range from 3 to 10% by weight, in each case based on the total weight of the oxidic material after calcination.


In particular embodiments, the oxidic material, in a fraction of at most 10% by weight, preferably at most 5% by weight, based on the total weight of the oxidic material after calcination, can have at least one further component which is selected from the group consisting of oxides of the elements Re, Fe, Ru, Co, Rh, Ir, Ni, Pd and Pt.


Preferably, the catalyst molding comprises no rhenium, no ruthenium, no iron and/or no zinc, in each case neither in metallic (oxidation state=0) nor in ionic (oxidation state≠0), in particular oxidized, form.


Preferably, the catalyst molding comprises no silver and/or molybdenum, in each case neither in metallic (oxidation state=0) nor in ionic (oxidation state≠0), in particular oxidized, form.


Preferably, the catalyst molding comprises no oxygen-containing compounds of silicon, zirconium and/or chromium.


Preferably, the catalyst molding comprises no oxygen-containing compounds of titanium.


In step iii, the mixture resulting from step ii is shaped to give a molding and then calcined. Preference is given to adding graphite to the mixture prior to shaping to give the molding. Preferably, the amount of graphite added is such that the shaping to give a molding can be carried out better. In a preferred embodiment, 0.5 to 5% by weight, particularly 1 to 3% by weight, of graphite, based on the total weight of the mixture resulting from step ii, are added.


The sum of the fractions of oxidic material, metallic copper powder and/or copper flakes and optionally graphite is preferably at least 95% by weight, particularly at least 98% by weight, of the catalyst molding.


The shaping in step iii leads preferably to tablets, rings, ring tablets, extrudates, honeycomb structures or similar moldings. Of suitability for this purpose are all processes known from the prior art.


After the shaping, moldings obtained are then calcined again, at least once. The calcination takes place in each case preferably over a period of in general 0.5 to 10 hours (h), particularly 0.5 to 2.5 hours. The temperature during this at least one calcination step (and also during the optional repeat calcination steps) is generally in the range from 200 to 600° C., preferably in the range from 250 to 500° C. and particularly preferably in the range from 270 to 400° C.


In a further embodiment, the molding obtained can also be treated with boiling water and/or water vapor before it is used for the amination.


In the case of use as catalyst in the oxidic form, the molding is prereduced prior to charging with the starting materials with reducing gases, for example hydrogen, preferably hydrogen/inert gas mixtures, in particular hydrogen/nitrogen mixtures, at elevated temperatures, e.g. in the range from 100 to 500° C., preferably in the range from 150 to 350° C. and in particular in the range from 180 to 200° C. Preference is given here to using a gas mixture with a hydrogen fraction in the range from 1 to 100% by volume, particularly preferably in the range from 1 to 50% by volume.


In a preferred embodiment, the molding is activated prior to being used as a catalyst in a manner known per se by treating with reducing media. The activation takes place either beforehand in a reducing furnace or following insertion in the reactor. If the reactor has been activated beforehand in the reducing furnace, it is incorporated into the reactor and charged directly with the starting materials under hydrogen pressure.


The process according to the invention is preferably carried out continuously, the catalyst preferably being arranged as a fixed bed in the reactor. In this connection, flow through the fixed catalyst bed from above and also from below is possible.


The primary amine III is used preferably in 0.5- to 20-fold molar amount, further preferably in a 2- to 17-fold molar amount, particularly in a 5- to 15-fold molar amount, in particular in a 6- to 14-fold molar amount, further particularly in a 7- to 13-fold molar amount, very particularly in a 8- to 12-fold molar amount, further very particularly in a 8- to 10-fold molar amount, in each case based on the DEOA used.


Particularly preferably, in the case of aminodiglycol (ADG) as primary amine III, the primary amine is used in a 0.5- to 2-fold, in particular in a 0.6- to 1.2-fold, molar amount, in each case based on the DEOA used.


Particularly preferably, in the case of monomethylamine (MMA) as primary amine III, the primary amine is used in a 4- to 13-fold, in particular in a 5- to 12-fold, molar amount, in each case based on the DEOA used.


Particularly preferably, in the case of monoethylamine (MEA) as primary amine III, the primary amine is used in a 2- to 10-fold, in particular in a 3- to 9-fold, molar amount, in each case based on the DEOA used.


The primary amine III can be used as aqueous solution, particularly as 30 to 95% strength by weight aqueous solution, e.g. also 65 to 90% strength by weight aqueous solution. Monomethylamine and monoethylamine are preferably also used without further solvent (compressed gas, purity particularly 95 to 100% strength by weight).


The starting material DEOA is preferably used as aqueous solution, particularly as 75 to 95% strength by weight aqueous solution, e.g. as 80 to 85% strength by weight aqueous solution.


Preferably, an offgas amount of from 5 to 800 cubic meters (stp)/(cubic meters of catalyst·h), in particular 20 to 300 cubic meters (stp)/(m3 of catalyst·h) is processed. [Cubic meters (stp)=volume converted to standard temperature and pressure conditions (20° C., 1 bar abs.)]. Catalyst volume data always refers to the bulk volume.


The amination of the primary alcohol groups of the starting material DEOA is carried out in the liquid phase. Preferably, the fixed bed process is in the liquid phase.


In the case of the continuous fixed bed process in the liquid phase, the following process configuration, which has inter alia a particularly advantageous effect on the catalyst performance, is particularly preferred. The starting materials (DEOA, primary amine III) including hydrogen are passed over the catalyst firstly at a temperature in the range from 80 to 160° C., preferably 100 to 140° C., particularly preferably 110 to 130° C., and then, e.g. after 1 to 240 min, preferably 5 to 120 min, particularly preferably 10 to 90 min, further particularly preferably 20 to 60 min, the temperature is increased to 180 to 240° C., particularly 180 to 235° C., preferably 185 to 230° C., in particular 190 to 225° C. Accordingly, a start-up procedure at lower temperatures is connected upstream. The reaction product resulting from the start-up procedure can be discarded or returned to the reaction.


When working in the liquid phase, the starting materials (DEOA, primary amine III) are passed, preferably simultaneously, in liquid phase at pressures of from 15.0 to 25.0 MPa (150 to 250 bar), preferably 15.5 to 23.0 MPa, further preferably 16.0 to 22.0 MPa, further preferably 16.5 to 21.5 MPa, particularly preferably 17.0 to 21.0 MPa, and at temperatures of in general 180 to 240° C., particularly 180 to 235° C., preferably 185 to 230° C., in particular 190 to 225° C., including hydrogen over the catalyst, which is usually located in a fixed-bed reaction heated preferably from the outside. Here, both a trickle mode and also a liquid-phase mode is possible. The catalyst hourly space velocity is generally in the range from 0.2 to 0.8, preferably 0.3 to 0.7, particularly preferably 0.4 to 0.6, further preferably 0.4 to 0.5 kg of DEOA per liter of catalyst (bed volume) and per hour (DEOA calculated as 100% strength). Optionally, the starting materials can be diluted with a suitable solvent, such as water, tetrahydrofuran, dioxane, N-methylpyrrolidone or ethylene glycol dimethyl ether. It is expedient to heat the reactants even before they are introduced into the reaction vessel, preferably to the reaction temperature.


The reaction is preferably carried out at a catalyst hourly space velocity in the range from 100 to 1500 liters (stp) of hydrogen/(lcat.·h), particularly a catalyst hourly space velocity in the range from 400 to 1400 liters of hydrogen (stp)/(lcat.·h).


[Liters (stp)=l (stp) volume converted to standard temperature and pressure conditions (20° C., 1 bar abs.)]


The pressure in the reaction vessel which arises from the sum of the partial pressures of the primary amine III, of the DEOA and of the reaction products formed, and also optionally of the co-used solvent at the stated temperatures, is expediently increased to the desired reaction pressure by injecting hydrogen.


In the case of continuous operation in the liquid phase, the excess primary amine III can be circulated together with the hydrogen.


If the catalyst is arranged as a fixed bed, it can be advantageous for the selectivity of the reaction to mix the catalyst moldings in the reactor with inert packings, to “dilute” them so to speak. The fraction of packings in such catalyst preparations can be 20 to 80, particularly 30 to 60 and in particular 40 to 50, parts by volume.


The water of reaction formed in the course of the reaction (in each case one mole per mole of reacted alcohol group) generally does not have a disruptive effect on the degree of conversion, the rate of reaction, the selectivity and the service life of the catalyst and is therefore expediently only removed upon working-up the reaction product, e.g. by distillation.


After the reaction discharge has expediently been decompressed, the excess hydrogen and the optionally present excess aminating agents are removed therefrom and the crude reaction product obtained is purified, e.g. by means of fractional rectification. Suitable work-up methods are described e.g. in EP 1 312 600 A and EP 1 312 599 A (both BASF AG). The excess primary amine and the hydrogen are advantageously returned again to the reaction zone. The same applies for any incompletely reacted DEOA.


A work-up of the product of the reaction is preferably as follows:


From the reaction product of the reaction, by means of distillation,


(i) firstly optionally unreacted primary amine III, R1 preferably =C1- to C5-alkyl, is separated off overhead,


(ii) water is separated off overhead,


(iii) optionally present by-products with a lower boiling point than that of the process product l (low boilers) are separated off overhead,


(iv) the process product mono-N-alkylpiperazine I is separated off overhead, with optionally present by-products with a higher boiling point than that of the process product l (high boilers) and optionally present unreacted DEOA (II) remaining in the bottom.


During the reaction of the process according to the invention, the alkylaminoethylethanolamine of the formula IV




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can be formed as by-product:




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Therefore, in particular by means of distillation,


(v) from the bottom of step iv, optionally present unreacted DEOA (II) and/or optionally present alkylaminoethylethanolamine as by-product with the formula IV are separated off overhead and returned to the reaction.


Primary amine III separated off in step i and having a purity of from 90 to 99.9% by weight, particularly 95 to 99.9% by weight, is preferably returned to the reaction where further preferably some of the separated-off amine III, particularly 1 to 30% by weight of the separated-off amine III, further particularly 2 to 25% by weight of the separated-off amine III, is removed.


A work-up of the product of the reaction of aminodiglycol (ADG), i.e. R1=2-(2-hydroxyethoxy)-ethyl, with DEOA is preferably as follows:


From the reaction product of the reaction, by means of distillation,


(i) firstly water is separated overhead,


(ii) optionally unreacted ADG is separated off overhead,


(iii) optionally present by-products with a lower boiling point than that of the process product I (low boilers) are separated overhead,


(iv) the process product mono-N-alkylpiperazine I is separated off overhead, with optionally present by-products with a higher boiling point than that of the process product l (higher boilers) and optionally present unreacted DEOA (II) remaining in the bottom.


In particular, by means of distillation,


(v) from the bottom of step iv, optionally present unreacted DEOA (II) and/or optionally present alkylaminoethylethanolamine as by-product with the formula IV are separated off overhead and returned to the reaction.


ADG separated off in step ii and having a purity of from 90 to 99.9% by weight, particularly 95 to 99.9% by weight, is preferably returned to the reaction where further preferably some of the separated-off ADG, particularly 1 to 30% by weight of the separated-off ADG, further particularly 5 to 25% by weight of the separated-off ADG, is removed.


All pressure data refer to the absolute pressure.


All ppm data refer to the mass.







EXAMPLES
1. Preparation of Catalyst A

A mixture of 13.39 kg of a 19.34% strength copper(II) nitrate solution and 14.78 kg of an 8.12% strength aluminum nitrate solution and 0.56 kg of a 37.58% strength lanthanum nitrate solution (feed material: lanthanum (III) nitrate.6H2O) were dissolved in 1.5 l of water (solution 1). Solution 2 was 60 kg of a 20% strength sodium carbonate solution (feed material: Na2CO3 anhydrous). Solution 1 and solution 2 were passed via separate lines to a precipitation vessel which was provided with a stirrer and comprised 10 l of water heated to 60° C. Here, by means of appropriate adjustment of the feed rates of solution 1 and solution 2, the pH was brought to 6.0.


While keeping the pH constant at 6.0 and the temperature constant at 60° C., the entire solution 1 was reacted with the sodium carbonate solution. The suspension formed in this way was then heated to 80° C., the pH was increased to 8.0 by adding dilute sodium carbonate solution (solution 2), and the mixture was after-stirred for 15 min at this pH and at 80° C. The suspension was filtered and washed with distilled water until the nitrate content of the wash water was <10 ppm.


The filter cake was dried for 16 h at 120° C. and then calcined for 2 h at 600° C. The catalyst powder obtained in this way was precompacted with 1% by weight of graphite. The resulting compacted material was mixed with 5% by weight of Cu flakes, which had a D50 value in the range from 5 to 40 μm (e.g. available from Schlenk Metallpulver GmbH & Co. KG, D-91154 Roth-Barnsdorf), and then with 2% by weight of graphite and compressed to give tablets 3 mm in diameter and 3 mm in height. Finally, the tablets were calcined for 2 h at 350° C.


The catalyst prepared in this way had the chemical composition 61.5% by weight of CuO/28.5% by weight of Al2O3/5.0% by weight of La2O3/5% by weight of Cu (graphite fraction excluded from the calculation).


2. Reaction of DEOA with Monomethylamine (MMA) in a Continuously Operated Tubular Reactor

A heated tubular reactor with an internal diameter of 14 mm, a centrally installed thermocouple and a total volume of 1000 ml was filled in the lower section with a bed of glass beads (250 ml), on top of this 500 ml of catalyst A and finally the remainder was filled again with glass beads. Prior to the reaction, the catalyst was activated under atmospheric pressure for 24 hours at max. 200° C. under hydrogen (25 l (stp)/h) (l (stp)=liters at standard temperature and pressure=volume converted to standard temperature and pressure conditions (20° C., 1 bar abs.)). 300 g/h of DEOA (85% strength aqueous), 600 g/h of the primary amine and 200 l (stp)/h of hydrogen were metered through the reactor from bottom to top. The reactor was held at a temperature of approx. 185 to 220° C. and a total pressure of 200 bar. The reaction temperature was selected such that a DEOA conversion of >90% was reached. The mixture leaving the reactor was cooled and decompressed to atmospheric pressure. At various times, samples were taken from the reaction mixture and analyzed by means of gas chromatography. For this, an “RTX-5 Amine” GC column 30 m in length was used, with a temperature program: 70° C./5 min, heat to 280° C. at a rate of 5° C./min, at 280° C./10 minutes. The results of the experiments can be found in table I below.

















TABLE I











Hourly space










velocity calc.




H2
MR


100% strength
Conversion
Sel. NMePIP



Pressure
l (stp)/
MMA:DEOA
Temp.

DEOA
of DEOA
based on


Cat.
bar
(l · h)
mol/mol
° C.
DEOA feed*)
kg/(l · h)
mol %
DEOA mol %























A
120
400
8
195
85% strength
0.5
98
73


A
200
400
8
195
85% strength
0.5
97
88


A
200
400
12
195
85% strength
0.5
97
89


A
200
400
5
195
85% strength
0.5
98
68





Cat.: Catalyst


Temp.: Temperature in the reactor


Hourly space velocity: Catalyst hourly space velocity [kg of DEOA/(litercat. · h)]


MR: Molar ratio in the feed


Sel.: Selectivity


NMePIP: Monomethylpiperazine (N-methyl-PIP)


*)Aqueous solution, in % by weight






3. Reaction of DEOA with Monoethylamine (MEA) in a Continuously Operated Tubular Reactor

A heated tubular reactor with an internal diameter of 14 mm, a centrally installed thermocouple and a total volume of 1000 ml was filled in the lower section with a bed of glass beads (250 ml), on top of this 500 ml of catalyst A and finally the remainder was filled again with glass beads. Prior to the reaction, the catalyst was activated under atmospheric pressure for 24 hours at max. 200° C. under hydrogen (25 l (stp)/h) [l (stp)=liters at standard temperature and pressure=volume converted to standard temperature and pressure conditions (20° C., 1 bar abs.)]. 180 g/h of DEOA (85% strength aqueous), 460 g/h of the primary amine and 2001 (stp)/h of hydrogen were metered through the reactor from bottom to top. The reactor was held at a temperature of approx. 185 to 220° C. and a total pressure of 200 bar. The reaction temperature was selected such that a DEOA conversion of >90% was reached. The mixture leaving the reactor was cooled and decompressed to atmospheric pressure. At various times, samples were taken from the reaction mixture and analyzed by means of gas chromatography. For this, an “RTX-5 amine” GC column 30 m in length was used, with a temperature program: 70° C./5 min, heat to 280° C. at a rate of 5° C./min, at 280° C./10 minutes.


The results of the experiments can be found in Table II below.

















TABLE II











Hourly space

Sel.








velocity calc.

NEtPIP




H2
MR


100% strength
Conversion
based on



Pressure
l (stp)/
MEA:DEOA
Temp.

DEOA
of DEOA
DEOA


Cat.
bar
(l · h)
mol/mol
° C.
DEOA feed*)
kg/(l · h)
mol %
mol %







A
200
400
5
217
85% strength
0.4
85
33


A
200
200
5
214
85% strength
0.4
93
39


A
200
200
3
202
85% strength
0.4
79
31


A
200
100
5
200
85% strength
0.2
95
44


A
200
100
9
211
85% strength
0.2
89
40


A
200
400
5
193
85% strength
0.3
82
35





Cat.: Catalyst


Temp.: Temperature in the reactor


Hourly space velocity: Catalyst hourly space velocity [kg of DEOA/(litercat. · h)]


MR: Molar ratio in the feed


Sel.: Selectivity


NEtPIP: Monoethylpiperazine (N-ethyl-PIP)


*)Aqueous solution, in % by weight






4. Reaction of DEOA with aminodiglycol (ADG, 1-amino-2-(2-hydroxyethoxy)ethane) in a Batch Reactor

A batch reactor with stirrer, a thermocouple and a total volume of 300 ml was filled with 7.5 g of activated catalyst. For this, the catalyst was activated under atmospheric pressure for 24 hours at max. 200° C. under hydrogen [25 l (stp)/h) (l (stp)=liter at standard temperature and pressure=volume converted to standard temperature and pressure conditions (20° C., 1 bar abs.)]. The starting material mixture of DEOA and ADG was initially introduced and the reactor was heated to 180° C. The total reaction mixture was then supplied with 200 bar of hydrogen. At various times, samples were taken from the reaction mixture and analyzed by means of gas chromatography. For this, an “RTX-5 amine” GC column 30 m in length was used, with a temperature program: 70° C./5 min, heat to 280° C. at a rate of 5° C./min, at 280° C./10 minutes. The results of the experiments can be found in Table III below.


















TABLE III













Sel..
Sel.










HEOEtPIP
HEOEtPIP







MR
Conversion
Conversion
based on
based on



Pressure
Temp.
Time
DEOA
ADG:DEOA
of
of
DEOA
ADG


Cat.
bar
° C.
(h)
(g)
mol/mol
DEOA
ADG
(mol %)
(mol %)
























A
200
180
5
77
1
43
43
7
8


A
200
180
10
77
1
68
71
16
19


A
200
180
15
77
1
84
86
22
27


A
200
180
20
77
1
93
93
24
31


A
200
180
10
90
0.67
74
89
13
25


A
200
180
15
90
0.67
89
97
17
29





Cat.: Catalyst


Temp.: Temperature in the reactor


MR: Molar ratio in the feed


Sel.: Selectivity (mol %)


Conversion: mol %


HEOEtPIP: 2-(2-Hydroxyethoxy)ethylpiperazine






5. Work-Up

The work-up can preferably take place by means of the following five steps (here using the example of a reaction of DEOA with monomethylamine or monoethylamine):


1) Separating off unreacted primary amine (monomethylamine or monoethylamine) and returning it to the reactor


Optionally removal of some of the monomethylamine or monoethylamine from the top of the column.


2) Separating off water


3) Separating off low-boiling secondary components


4) Pure distillation of the N-alkylpiperazine I overhead while separating off high-boiling secondary components via the bottom.


5) Optionally returning some of the high-boiling secondary components, in particular diethanolamine, N—(N′-methyl-2-aminoethyl)ethanolamine, N-methyl-N-(2-aminoethyl)-ethanolamine (or N—(N′-ethyl-2-aminoethyl)ethanolamine, N-ethyl-N-(2-amino-ethyl)ethanolamine) to the reaction.

Claims
  • 1. A process for the preparation of a mono-N-alkylpiperazine of the formula I
  • 2. The process according to claim 1, wherein the oxidic material comprises (a) copper oxide with a fraction in the range from 50≦x≦80% by weight, calculated as CuO,(b) aluminum oxide with a fraction in the range from 15≦y≦35% by weight and(c) lanthanum oxide with a fraction in the range from 2≦z≦20% by weight,in each case based on the total weight of the oxidic material after calcination, where: 80≦x+y+z≦100.
  • 3. The process according to claim 1, wherein the oxidic material comprises (a) copper oxide with a fraction in the range from 55≦x≦75% by weight, calculated as CuO,(b) aluminum oxide with a fraction in the range from 20≦y≦30% by weight and(c) lanthanum oxide with a fraction in the range from 3≦z≦15% by weight,in each case based on the total weight of the oxidic material after calcination, where: 80≦x+y+z≦100.
  • 4. The process according to claim 1, wherein the oxidic material comprises (a) copper oxide with a fraction in the range from 55≦x≦75% by weight, calculated as CuO,(b) aluminum oxide with a fraction in the range from 20≦y≦30% by weight and(c) lanthanum oxide with a fraction in the range from 3≦z≦15% by weight,in each case based on the total weight of the oxidic material after calcination, where: 95≦x+y+z≦100.
  • 5. The process according to claim 1, wherein, in step ii, graphite is added in amounts in the range from 0.5 to 5% by weight, based on the total weight of the oxidic material after calcination.
  • 6. The process according to claim 1, wherein pulverulent copper and/or the copper flakes taken together are added in amounts in the range from 0.5 to 40% by weight, based on the total weight of the oxidic material after calcination.
  • 7. The process according to claim 1, wherein 0.5 to 5% by weight of graphite is added to the mixture resulting from step ii prior to the shaping in step iii, based on the total weight of the mixture resulting from step ii.
  • 8. The process according to claim 1, wherein the sum of the fractions of oxidic material, metallic copper powder and/or copper flakes and optionally graphite is at least 95% by weight of the catalyst molding.
  • 9. The process according to claim 1, wherein the catalyst molding comprises no rhenium and/or ruthenium.
  • 10. The process according to claim 1, wherein the catalyst molding comprises no iron and/or zinc.
  • 11. The process according to claim 1, wherein the catalyst molding comprises no oxygen-containing compounds of silicon and/or of zirconium and/or of titanium.
  • 12. The process according to claim 1, wherein the reaction is carried out at a temperature in the range from 180 to 240° C.
  • 13. The process according to claim 1, wherein the reaction is carried out at an absolute pressure in the range from 160 to 220 bar.
  • 14. The process according to claim 1, wherein the primary amine of the formula H2N—R1 (III) is used in a 5- to 15-fold molar amount, based on the DEOA used.
  • 15. The process according to claim 1, wherein aminodiglycol (ADG) is used in a 0.2- to 2-fold molar amount, based on the DEOA used.
  • 16. The process according to claim 1, wherein monomethylamine (MMA) is used in a 4- to 13-fold molar amount, based on the DEOA used.
  • 17. The process according to claim 1, wherein monoethylamine (MEA) is used in a 2- to 10-fold molar amount, based on the DEOA used.
  • 18. The process according to claim 1, wherein the catalyst is arranged as a fixed bed in the reactor.
  • 19. The process according to claim 1, wherein the reacting diethanolamine (DEOA) of the formula II
  • 20. The process according to claim 18, wherein the reaction is carried out firstly at a temperature in the range from 80 to 160° C. and then at a temperature in the range from 180 to 240° C.
  • 21. The process according to claim 18, wherein the reaction takes place in a tubular reactor.
  • 22. The process according to claim 18, wherein the reaction takes place in a circulating-gas mode.
  • 23. The process according to claim 1, wherein the DEOA is used as aqueous solution.
  • 24. The process according to claim 1, wherein the primary amine of the formula H2N—R1 (III) is used as aqueous solution.
  • 25. The process according to claim 1, wherein the reaction is carried out at a catalyst hourly space velocity in the range from 0.3 to 0.7 kg of DEOA/(lcat.·h).
  • 26. The process according to claim 1, wherein the reaction is carried out at a catalyst hourly space velocity in the range from 400 to 1400 liters (stp) of hydrogen/(lcat.·h).
  • 27. The process according to claim 1 for the preparation of a mono-N-alkylpiperazine of the formula I in which R1 is methyl, ethyl or 2-(2-hydroxyethoxy)ethyl, by reacting diethanolamine (DEOA) of the formula II with a primary amine of the formula H2N—R1 (III).
  • 28. A process for the preparation of a mono-N-alkylpiperazine of the formula I
  • 29. The process according to claim 28, wherein, by distillation, (v) from the bottom of step iv, optionally present unreacted DEOA (II) and/or optionally present alkylaminoethylethanolamine as by-product with the formula IV
  • 30. The process according to claim 28, wherein primary amine III separated off in step i and having a purity of from 90 to 99.9% by weight is returned to the reaction.
  • 31. A process for the preparation of a mono-N-alkylpiperazine of the formula I
  • 32. The process according to claim 31, wherein, by distillation, (v) from the bottom of step iv, optionally present unreacted DEOA (II) and/or optionally present alkylaminoethylethanolamine as by-product with the formula IV
  • 33. The process according to claim 31, wherein ADG separated off in step ii and having a purity of 90 to 99.9% by weight is returned to the reaction, where some of the ADG is removed.
  • 34. The process according to claim 28, wherein primary amine III separated off in step i and having a purity of from 90 to 99.9% by weight is returned to the reaction, with some of the amine III being removed.
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit (under 35 USC 119(e)) of U.S. Provisional Application 61/654,132, filed Jun. 1, 2012, which is incorporated by reference.

US Referenced Citations (48)
Number Name Date Kind
3166558 Mascioli Jan 1965 A
3275554 Wagenaar Sep 1966 A
3751475 van der Voort et al. Aug 1973 A
3997368 Petroff et al. Dec 1976 A
4014933 Boettger et al. Mar 1977 A
4323550 Goupil Apr 1982 A
4442306 Mueller et al. Apr 1984 A
4739051 Schroeder et al. Apr 1988 A
4832702 Kummer et al. May 1989 A
4845218 Schroeder Jul 1989 A
4851578 Fischer et al. Jul 1989 A
4851580 Mueller et al. Jul 1989 A
4910304 Fischer et al. Mar 1990 A
5002922 Irgang et al. Mar 1991 A
5110928 Schroeder et al. May 1992 A
5463130 Witzel et al. Oct 1995 A
5530127 Reif et al. Jun 1996 A
5847131 Simon et al. Dec 1998 A
6187957 Meyer et al. Feb 2001 B1
6448457 Hesse et al. Sep 2002 B1
7750189 Kubanek et al. Jul 2010 B2
8436169 Wigbers et al. May 2013 B2
8450530 Mueller et al. May 2013 B2
20030089591 Wolfert et al. May 2003 A1
20050000791 Wolfert et al. Jan 2005 A1
20070232833 Haese et al. Oct 2007 A1
20080064882 Huber-Dirr et al. Mar 2008 A1
20080255351 Hoffer et al. Oct 2008 A1
20080299390 Houssin et al. Dec 2008 A1
20090286977 Kubanek et al. Nov 2009 A1
20100069681 Heimann et al. Mar 2010 A1
20100274010 Kubanek et al. Oct 2010 A1
20100274055 Kubanek et al. Oct 2010 A1
20110054167 Kubanek et al. Mar 2011 A1
20110137029 Kubanek et al. Jun 2011 A1
20110137030 Kubanek et al. Jun 2011 A1
20110172430 Ernst et al. Jul 2011 A1
20110218270 Suter et al. Sep 2011 A1
20110218323 Dahmen et al. Sep 2011 A1
20110251433 Wigbers et al. Oct 2011 A1
20110288337 Chedid et al. Nov 2011 A1
20110288338 Wigbers et al. Nov 2011 A1
20110294977 Schaub et al. Dec 2011 A1
20120035049 Kubanek et al. Feb 2012 A1
20120035399 Abillard et al. Feb 2012 A1
20120095221 Wigbers et al. Apr 2012 A1
20120157679 Wigbers et al. Jun 2012 A1
20130331573 Bou Chedid et al. Dec 2013 A1
Foreign Referenced Citations (70)
Number Date Country
1046166 Jan 1979 CA
1055677 Jun 1979 CA
102101847 Jun 2011 CN
102304101 Jan 2012 CN
917 784 Sep 1954 DE
941 909 Apr 1956 DE
1954546 May 1971 DE
21 25039 Dec 1971 DE
1953263 Feb 1972 DE
2445303 Apr 1976 DE
26 28 087 Jan 1977 DE
2706826 Sep 1977 DE
36 11 230 Oct 1987 DE
4021230 Jan 1991 DE
4028295 Mar 1992 DE
19809418 Sep 1999 DE
19859776 Jun 2000 DE
10218849 Nov 2003 DE
70 512 Jan 1983 EP
75940 Apr 1983 EP
0137478 Apr 1985 EP
0227904 Jul 1987 EP
235651 Sep 1987 EP
0257443 Mar 1988 EP
382049 Aug 1990 EP
0434062 Jun 1991 EP
440829 Aug 1991 EP
446783 Sep 1991 EP
514 692 Nov 1992 EP
552 463 Jul 1993 EP
599 180 Jun 1994 EP
673 918 Sep 1995 EP
696572 Feb 1996 EP
0816350 Jan 1998 EP
1 312 599 May 2003 EP
1 312 600 May 2003 EP
1512797 Jun 1978 GB
62145076 Jun 1987 JP
WO-9204119 Mar 1992 WO
WO-03051508 Jun 2003 WO
WO-2004085356 Oct 2004 WO
WO-2005110969 Nov 2005 WO
WO-2006005505 Jan 2006 WO
WO-2006114417 Nov 2006 WO
WO-2007036496 Apr 2007 WO
WO-2008006750 Jan 2008 WO
WO-2008006754 Jan 2008 WO
WO-2009027249 Mar 2009 WO
WO-2009080506 Jul 2009 WO
WO-2009080507 Jul 2009 WO
WO-2009080508 Jul 2009 WO
WO-2010031719 Mar 2010 WO
WO-2010052181 May 2010 WO
WO-2010054988 May 2010 WO
WO-2010069856 Jun 2010 WO
WO-2010089265 Aug 2010 WO
WO-2010089266 Aug 2010 WO
WO-2010089346 Aug 2010 WO
WO-2010103062 Sep 2010 WO
WO-2010106133 Sep 2010 WO
WO-2010115759 Oct 2010 WO
WO-2010146009 Dec 2010 WO
WO-2011067200 Jun 2011 WO
WO-2011067199 Jun 2011 WO
WO-2011082967 Jul 2011 WO
WO-2011082994 Jul 2011 WO
WO-2011107512 Sep 2011 WO
WO-2011115759 Sep 2011 WO
WO-2011157710 Dec 2011 WO
WO-2012049101 Apr 2012 WO
Non-Patent Literature Citations (7)
Entry
U.S. Appl. No. 13/906,960, filed May 31, 2013.
U.S. Appl. No. 13/910,554, filed Jun. 5, 2013.
U.S. Appl. No. 13/910,602, filed Jun. 5, 2013.
Database WPI, Week 198731, Thomson Scientific, London, GA; AN 1987-218358 (XP002664153), & JP 62 145076 A (KOA Corp) Jun. 29, 1987.
International Search Report for PCT/EP2011/059848—Jun. 14, 2011, dated Jul. 25, 2011.
International Search Report for PCT/EP2011/067612 dated Nov. 22, 2011.
International Search Report for PCT/EP2011/068700, mailed Feb. 17, 2012.
Related Publications (1)
Number Date Country
20130324731 A1 Dec 2013 US
Provisional Applications (1)
Number Date Country
61654132 Jun 2012 US