阅读说明：本技术 连续制备1,2-丙二胺(1,2-pda)和二甲基二亚乙基三胺(dmdeta)的方法 (Process for the continuous preparation of 1, 2-propanediamine (1,2-PDA) and dimethyldiethylenetriamine (DMDETA) ) 是由 C·艾达姆肖斯 J-P·梅尔德 J·帕斯特尔 H-J·帕拉施 于 2018-11-19 设计创作，主要内容包括：本发明涉及一种通过在氢气和负载型多相氢化催化剂(催化剂)存在下使单异丙醇胺(MIPOA)与氨反应而连续制备1,2-丙二胺(1,2-PDA)和二甲基二亚乙基三胺(DMDETA)的方法,其特征在于反应在液相中于60-170巴的绝对压力下进行。(The invention relates to a process for the continuous preparation of 1, 2-propanediamine (1,2-PDA) and dimethyldiethylenetriamine (DMDETA) by reacting Monoisopropanolamine (MIPOA) with ammonia in the presence of hydrogen and a supported heterogeneous hydrogenation catalyst (catalyst), characterized in that the reaction is carried out in the liquid phase at an absolute pressure of 60 to 170 bar.)

1. A process for the continuous preparation of 1, 2-propanediamine (1,2-PDA) and dimethyldiethylenetriamine (DMDETA) by reaction of Monoisopropanolamine (MIPOA) with ammonia in the presence of hydrogen and a supported heterogeneous hydrogenation catalyst (catalyst), wherein the reaction is carried out in the liquid phase at an absolute pressure of from 60 to 170 bar.

2. The process of claim 1 wherein the reaction is carried out in a reactor and the reactor output is separated by distillation, wherein

(1) The reactor output is fed to a first distillation column K1, in which ammonia is removed from the side draw or from the top,

(2) the bottom output from K1 is fed to a second distillation column K2, in which water is removed from the side offtake or the top,

(3) the bottom output from K2 is fed to a third distillation column K3, in which 1,2-PDA is removed from the side or overhead,

(4) the bottom output from K3 is fed to a fourth distillation column K4, in which DMDETA is removed at the bottom, MIPOA is removed from the side cut, and low boilers are removed from the top.

3. The process according to the preceding claim, wherein the ammonia obtained in step (1) and/or the MIPOA obtained in step (4) is recycled to the reaction.

4. The process according to any of the preceding claims, wherein the catalytically active composition of the catalyst comprises an oxygen-containing compound of aluminium and an oxygen-containing compound of copper, nickel and/or cobalt prior to reduction of the catalyst with hydrogen.

5. A process according to any one of the preceding claims wherein the catalytically active composition of the catalyst prior to reduction of the catalyst with hydrogen comprises oxygen-containing compounds of aluminium, copper, nickel and cobalt and 0.2 to 5.0 wt.% of oxygen-containing compounds of tin, calculated as SnO.

6. A process according to any one of the preceding claims wherein the catalytically active composition of the catalyst comprises 0.4 to 4.0% by weight, calculated as SnO, of an oxide of tin prior to reduction of the catalyst with hydrogen.

7. The process according to any of the preceding claims, wherein the catalytically active composition of the catalyst comprises 5.0 to 35 wt.% of oxygen-containing compounds of cobalt, calculated as CoO, before reduction of the catalyst with hydrogen.

8. A process according to any one of claims 1 to 5 wherein the catalytically active composition of the catalyst comprises from 10 to 30% by weight, calculated as CoO, of oxygen-containing compounds of cobalt prior to reduction of the catalyst with hydrogen.

9. The process according to any one of the preceding claims, wherein the catalytically active composition of the catalyst comprises prior to reduction of the catalyst with hydrogen

With Al₂O₃15-80% by weight calculated on aluminum oxide,

1.0 to 20% by weight, calculated as CuO, of oxygen-containing compounds of copper, and

5.0 to 35 wt.% of an oxygen-containing compound of nickel, calculated as NiO.

10. The process of any of claims 1 to 7 wherein the catalytically active composition of the catalyst comprises prior to reduction of the catalyst with hydrogen

With Al₂O₃30-70% by weight, calculated as aluminum, of an oxygen-containing compound,

from 2.0 to 18% by weight, calculated as CuO, of oxygen-containing compounds of copper, and

10-30 wt% of an oxygen-containing compound of nickel calculated as NiO.

11. The process according to any of the preceding claims, wherein the catalytically active composition of the catalyst does not contain any rhenium and/or ruthenium.

12. The process according to any of the preceding claims, wherein the catalytically active composition of the catalyst does not contain any iron and/or zinc.

13. The process according to any of the preceding claims, wherein the catalytically active composition of the catalyst does not contain any silicon and/or zirconium oxygenates.

14. A process according to any one of the preceding claims wherein the absolute pressure is from 70 to 145 bar.

15. The process according to any of the preceding claims, wherein the reaction temperature during the reaction is 160-195 ℃.

16. The process according to any of the preceding claims, wherein the reaction is carried out in the presence of 1.2-4.5 wt% of hydrogen based on the amount of MIPOA used.

17. The process according to any of the preceding claims, wherein ammonia is used in a molar amount of 5-30 times based on MIPOA.

Prior Art

1,2-PDA is used, inter alia, as an intermediate for the preparation of fuel additives, surfactants, pharmaceuticals and crop protection products, as a curing agent for epoxy resins, as a catalyst for polyurethanes, as an intermediate for the preparation of quaternary ammonium compounds, as a plasticizer, as a corrosion inhibitor, as a synthetic resin, as an ion exchanger, as a textile auxiliary, as a dye, as a vulcanization accelerator and/or as an emulsifier. For example, DMDETA can be used as an epoxy curing agent.

WO 03/051508 a1(Huntsman Petrochemical Corp.) relates to a process for the amination of alcohols using a specific Cu/Ni/Zr/Sn containing catalyst which in another embodiment comprises Cr instead of Zr (see page 4, lines 10-16). The catalyst described in this WO application does not contain any aluminium oxide or cobalt.

WO 2008/006750 a1(BASF AG) relates to specific Pb, Bi, Sn, Sb and/or In doped zirconium dioxide, copper, nickel and cobalt containing catalysts and their use In a process for the preparation of amines by reacting primary or secondary alcohols, aldehydes and/or ketones with hydrogen and ammonia or primary or secondary amines. No alumina support is taught.

WO 2009/080507 a1(BASF SE) relates to specific Sn-and Co-doped zirconium dioxide, copper and nickel-containing catalysts and their use in a process for preparing amines by reacting primary or secondary alcohols, aldehydes and/or ketones with hydrogen and ammonia or primary or secondary amines. No alumina support is taught.

WO 2009/080506 a1(BASF SE) describes specific Pb, Bi, Sn, Mo, Sb and/or P doped zirconium dioxide, nickel and iron containing catalysts and their use in a process for the preparation of amines by reacting primary or secondary alcohols, aldehydes and/or ketones with hydrogen and ammonia or primary or secondary amines. No alumina support is taught. The catalyst preferably does not contain any Cu or Co.

WO 2009/080508 a1(BASF SE) teaches specific Pb, Bi, Sn and/or Sb doped zirconium dioxide, copper, nickel, cobalt and iron containing catalysts and their use in a process for the preparation of amines by reacting primary or secondary alcohols, aldehydes and/or ketones with hydrogen and ammonia or primary or secondary amines. No alumina support is taught.

WO 2009/114438A 2(Huntsman petrochem. Corp.) relates to the use of a catalyst for the oxidation of ZrO in the presence of hydrogen and ZrO₂Supported metal catalysts, e.g. ZrO₂Amination of cyclohexanedimethanol in the presence of/Cu/Ni/Sn.

1,2-PDA can be prepared by reacting Monoisopropanolamine (MIPOA) with ammonia and hydrogen in the presence of a suitable catalyst.

WO 2011/067199 a1(BASF SE) describes a process for the preparation of amines by reacting primary or secondary alcohols, aldehydes or ketones with hydrogen and ammonia in the presence of a supported copper, nickel and cobalt containing catalyst comprising 0.2 to 5.0 wt.% of an oxygen containing compound of tin, calculated as SnO. This description generally describes 2-hydroxypropylamine and NH₃Reaction (page 25, line 25).

CN 104693037A (Dalian Institute of Chemical Physics) describes the reaction of isopropanolamine and ammonia in the presence of hydrogen at a pressure of 20 to 250 bar and a temperature of 120 ℃ and 230 ℃ over a catalyst comprising Ni and/or Cu and a promoter selected from the group consisting of Fe, Cu, Ru, Re, K, Zn and B, the support used being SiO₂And/or Al₂O₃。

DMDETA can be prepared in up to 24% yield, for example, by reacting 1,2-PDA with methylaziridine (as described in US2011/151615a1(President and Fellows of Harvard College)). 1, 2-dichloropropane may also be reacted with ammonia (K.V.Chernitskii, V.A.Bobylev, J.Gen.chem.USSR, 1990, 60, 1636-. Furthermore, it is theoretically possible to obtain DMDETA as a so-called by-product (valuable product) when preparing 1, 2-PDA. This involves reacting the already formed 1,2-PDA with unconverted MIPOA to produce DMDETA and eliminate water. However, it is generally not possible to obtain a sufficient amount of DMDETA because it cyclizes to produce dimethylpiperazine and eliminates ammonia. Therefore, the formation of the valuable product DMDETA has not been described in the prior art.

The present invention is based on the object of remedying one or more of the drawbacks of the prior art. In particular, the aim was to find a process for the preparation of 1,2-PDA, in which a significant amount of DMDETA is formed simultaneously. Conditions should be found which can be formed technically simply and are therefore cost-effective and which make it possible to carry out the process efficiently, in particular with high conversions, high yields, space-time yields (STY) and selectivities and at the same time high mechanical stability of the shaped catalyst bodies. Furthermore, methods should be found to obtain 1,2-PDA and DMDETA of the highest possible purity.

[ space-time yield in "amount of product/(catalyst volume ● time)" (kg/(l)_{Catalyst and process for preparing same}● h)) and/or "amount of product/(reactor volume ● time)" (kg/(l) time (s))_{Reactor with a reactor shell}● h)) report]。

Surprisingly, a process has been found for the continuous preparation of 1, 2-propanediamine (1,2-PDA) and dimethyldiethylenetriamine (DMDETA) by reaction of Monoisopropanolamine (MIPOA) with ammonia in the presence of hydrogen and a supported heterogeneous hydrogenation catalyst (catalyst), wherein the reaction is carried out in the liquid phase at an absolute pressure of from 60 to 170 bar.

Description of the invention

For example, catalysts can be used whose catalytically active composition, before reduction thereof with hydrogen, comprises oxygen-containing compounds of aluminum and oxygen-containing compounds of copper, nickel and/or cobalt.

Preference is given to catalysts whose catalytically active composition, before reduction with hydrogen, comprises oxygen-containing compounds of aluminum, copper, nickel and cobalt and from 0.2 to 5.0% by weight, calculated as SnO, of oxygen-containing compounds of tin.

In the amination process described above, use is made, inter alia, of catalysts whose catalytically active composition, before reduction thereof with hydrogen, comprises:

oxygen-containing combination of 15-80 wt.% aluminumObject (with Al)₂O₃A meter),

1 to 20% by weight of oxygen-containing compounds of copper (calculated as CuO),

5-35 wt.% of an oxygen-containing compound of nickel (calculated as NiO),

5 to 35% by weight of oxygen-containing compounds of cobalt, calculated as CoO, and

0.2 to 5.0% by weight of oxygen-containing compounds of tin (calculated as SnO).

Preferably the reactor is a tubular reactor. Examples of suitable reactors comprising a recycle gas stream are described in Ullmann's encyclopedia of Industrial Chemistry, 5 th edition, volume B4, pages 199-.

Alternatively, the reaction is advantageously carried out in a shell-and-tube reactor or in a single-flow apparatus. In a single flow arrangement, the tubular reactor in which the reaction is carried out may be constituted by a plurality (e.g. 2 or 3) of individual tubular reactors connected in series. A possible and advantageous option in this case is the feed (comprising MIPOA and/or ammonia and/or H)₂) And/or intermediate introduction of recycle gas and/or reactor output of a downstream reactor.

At H₂In the case of a content of 80% by volume, the amount of circulating gas is preferably from 10 to 450Nm³/[m³Catalyst (bed volume). h]In particular 15-450Nm³/[m³Catalyst (bed volume). h]More particularly 20-400Nm³/[m³Catalyst (bed volume). h]Very particularly from 25 to 400Nm³/[m³Catalyst (bed volume). h]E.g. 35-360Nm³/[m³Catalyst (bed volume). h]。

For different H₂Content, the amount of the above-mentioned circulating gas is mathematically changed accordingly to maintain H₂Amount (in Nm)³/[m³Catalyst (bed volume). h]Meter) is constant.

[Nm³Volume converted to standard conditions (20 ℃, 1 bar absolute)]。

(Standard pressure 1 absolute bar)

In the process of the invention, if the catalyst is used in the form of shaped bodies, i.e. without any other catalytically active accompanying substances, the catalyst is preferably used in the form of a catalyst consisting only of the catalytically active composition and optionally a shaping aid (e.g. graphite or stearic acid).

In this connection, the oxide support material alumina (Al)₂O₃) Are considered to belong to the catalytically active composition.

The catalyst was used in the following manner: the catalytically active composition ground to powder is introduced into the reaction vessel or, after grinding, mixing with shaping assistants, shaping and heat treatment, is placed in the reactor in the form of shaped catalyst bodies, for example in the form of tablets, spheres, rings, extrudates (e.g. strands).

Unless otherwise stated, the concentration values (in% by weight) of the individual components of the catalyst are in each case based on the catalytically active composition of the finished catalyst after its final heat treatment and before its reduction with hydrogen.

After its final heat treatment and before its reduction with hydrogen, the catalytically active composition of the catalyst is defined as the sum of the mass of the catalytically active components and the above-mentioned catalyst support material and essentially comprises the following components: alumina (Al)₂O₃) Oxygen-containing compounds of copper, nickel and cobalt and oxygen-containing compounds of tin.

The sum of the abovementioned components of the catalytically active composition is generally from 70 to 100% by weight, preferably from 80 to 100% by weight, particularly preferably from 90 to 100% by weight, in particular > 95% by weight, very particularly > 98% by weight, in particular > 99% by weight, for example particularly preferably 100% by weight.

The catalysts of the invention and the catalytically active compositions of those used in the process of the invention may also comprise one or more elements selected from groups IA to VIA and IB to VIIB and VIII of the periodic table (oxidation state 0) or inorganic or organic compounds thereof.

Examples of such elements and their compounds are as follows: transition metals, e.g. Mn or MnO₂W or tungsten oxide, Ta or tantalum oxide, Nb or niobium oxide or niobium oxalate, V or vanadium oxide or vanadyl pyrophosphate; lanthanides, e.g. Ce or CeO₂Or Pr₂O₃(ii) a Alkaline earth metal oxides such as SrO; alkaline earth metal carbonates such as MgCO₃、CaCO₃And BaCO₃(ii) a And boron oxide (B)₂O₃)。

The catalyst of the invention and the catalytically active compositions of those used in the process of the invention are preferably free of any rhenium, any ruthenium, any iron and/or any zinc, in each case in metallic form (oxidation state ≠ 0) or in ionic form (oxidation state ≠ 0), in particular in oxidized form.

The catalysts of the invention and the catalytically active compositions of those used in the process of the invention are preferably free of any silver and/or any molybdenum, in each case in metallic form (oxidation state ≠ 0) or in ionic form (oxidation state ≠ 0), in particular in oxidized form.

In a particularly preferred embodiment, the catalyst of the invention and the catalytically active composition of those used in the process of the invention are free of any further catalytically active component in elemental form (oxidation state ≠ 0) or in ionic form (oxidation state ≠ 0).

In a particularly preferred embodiment, the catalytically active composition is not doped with other metals or metal compounds.

Preferably, however, this excludes trace elements normally associated with metal extraction from Cu, Co, Ni and/or Sn.

The catalytically active composition of the catalyst preferably does not contain any silicon and/or zirconium-containing oxygen compounds.

The catalytically active composition of the catalyst preferably does not contain any oxygen-containing compounds of titanium and/or chromium.

The catalytically active composition of the catalyst comprises, before its reduction with hydrogen, from 0.2 to 5.0% by weight, in particular from 0.4 to 4.0% by weight, more particularly from 0.6 to 3.0% by weight, and very particularly preferably from 0.7 to 2.5% by weight, of oxygen-containing compounds of tin (calculated as SnO).

The catalytically active composition of the catalyst comprises, before its reduction with hydrogen, preferably from 5.0 to 35% by weight, in particular from 10 to 30% by weight, more particularly from 12 to 28% by weight, very particularly from 15 to 25% by weight, of oxygen-containing compounds of cobalt, calculated as CoO.

The catalytically active composition of the catalyst further preferably comprises, before its reduction with hydrogen:

15 to 80% by weight, in particular 30 to 70% by weight, more in particular 35 to 65% by weight, of aluminum oxygen-containing compounds (in each case as Al)₂O₃A meter);

1 to 20% by weight, in particular 2 to 18% by weight, more in particular 5 to 15% by weight, of oxygen-containing compounds of copper (in each case calculated as CuO); and

5 to 35% by weight, in particular 10 to 30% by weight, more particularly 12 to 28% by weight, very particularly 15 to 25% by weight, of oxygen-containing compounds of nickel (in each case calculated as NiO).

The molar ratio of nickel to copper is preferably greater than 1, particularly preferably greater than 1.2, very particularly preferably from 1.8 to 8.5.

The BET surface area of the catalysts of the invention and those used in the process of the invention (ISO 9277:1995) is preferably from 30 to 250m²In particular from 90 to 200 m/g²(iv)/g, more particularly 130-²In each case before reduction with hydrogen. These ranges are obtained in particular by the calcination temperature during the catalyst preparation of 400-600 deg.C, in particular 420-550 deg.C (see below).

Various methods can be used to prepare the catalysts for use in the process of the present invention. For example, the catalyst may be obtained by peptizing a powdered mixture of hydroxides, carbonates, oxides and/or other salts of the components with water, followed by extrusion and heat treatment of the resulting composition.

The catalyst of the invention is preferably prepared using a precipitation process. Thus, it can be obtained, for example, by coprecipitation of nickel, cobalt, copper and Sn components from an aqueous salt solution comprising the elements nickel, cobalt, copper and Sn by means of a base in the presence of a suspension of a sparingly soluble oxygen-containing aluminum compound and subsequent washing, drying and calcination of the precipitate obtained. Sparingly soluble aluminum oxo compounds which can be used include, for example, aluminum oxide hydrate, aluminum phosphate, aluminum borate and aluminum silicate. Suspensions of sparingly soluble aluminum compounds can be prepared by suspending fine powders of these compounds in water under vigorous stirring. Advantageously, these suspensions are obtained by precipitation of sparingly soluble aluminum compounds from aqueous solutions of aluminum salts by means of a base.

The catalyst of the invention is preferably prepared by coprecipitation (co-precipitation) of all its components. For this purpose, the aqueous salt solution comprising the catalyst components is advantageously mixed under thermal conditions with stirring with an aqueous base (for example sodium carbonate, sodium hydroxide, potassium carbonate or potassium hydroxide) until the precipitation is complete. Alkali metal-free bases such as ammonia, ammonium carbonate, ammonium bicarbonate, ammonium carbamate, ammonium oxalate, ammonium malonate, urotropin, urea, and the like can also be used. The nature of the salt used is generally not important since the main factor in the procedure is the water solubility of the salt, the criterion being that it has good water solubility required to prepare these relatively highly concentrated salt solutions. It is considered self-evident that when selecting the salts of the individual components, the salts selected are of course only those having anions which do not cause damage, whether causing undesirable precipitation or hindering or preventing precipitation by complex formation.

The precipitates obtained in these precipitation reactions are generally chemically heterogeneous and consist in particular of the oxides, oxide hydrates, hydroxides, carbonates and mixtures of insoluble and basic salts of the metals used. In terms of filterability of the precipitate, it may prove advantageous to age it, i.e. to leave it for a period of time after precipitation, optionally under hot conditions or to let air pass.

The precipitate obtained after these precipitation processes is subjected to conventional further treatment to obtain the catalyst of the invention. The precipitate is first washed. The alkali metal content provided by the (inorganic) base and available as a precipitant can be influenced by the duration of the washing operation and the temperature and amount of the washing water. In general, increasing the washing time or increasing the temperature of the washing water reduces the alkali metal content. After washing, the precipitated material is generally dried at 80-200 ℃, preferably at 100-150 ℃ and then calcined. The calcination is generally carried out at a temperature of 300-800 deg.C, preferably 400-600 deg.C, especially 420-550 deg.C.

The catalysts of the invention can also be prepared by reacting, for example, alumina (Al) in the form of a powder or shaped bodies, such as wires, flakes, spheres or rings₂O₃) And (3) dipping to prepare the coating.

Alumina is used, for example in amorphous, gamma, theta and/or form, preferably in amorphous form, as the basic aluminium hydroxide (boehmite) form.

The shaped bodies can be prepared by conventional methods.

Impregnation is likewise carried out by conventional methods, for example by applying the corresponding appropriate metal salt solutions in one or more impregnation steps, as described in A.B. Stiles, Catalyst Manufacture-L organism and Commercial Preparations, Marcel Dekker, New York (1983), where the metal salts used are, for example, the corresponding nitrates, acetates or chlorides.

The impregnation can be carried out by the so-called incipient wetness method, in which the alumina is wetted according to its water-absorbing capacity up to the maximum saturation of the impregnation solution. Alternatively, the impregnation may be carried out in a supernatant solution.

In the case of a multistage impregnation process, drying and optionally calcination are suitably carried out between the impregnation steps. Multistage impregnation can be advantageously used, in particular when the alumina is loaded with a relatively large amount of metal.

For application of the metal components to the alumina, the impregnation can be carried out simultaneously with all metal salts or sequentially with the metal salts alone in any desired order.

The catalyst prepared by impregnation is subsequently dried and preferably also calcined, for example in the calcination temperature range already described above.

After calcination, the catalyst is suitably adjusted, whether it is adjusted to a certain particle size by grinding, or mixed with a shaping aid, such as graphite or stearic acid, after grinding, or pressed into a molding (e.g. a tablet) by means of a press and subjected to a heat treatment. The heat treatment temperature at this time preferably corresponds to the temperature during calcination.

The catalysts prepared in this way comprise the catalytically active metals in the form of mixtures of their oxygen-containing compounds, i.e. in particular in the form of oxides and mixed oxides.

The catalyst, e.g. prepared as described above, is stored as such and optionally traded. It is usually pre-reduced before it is used as a catalyst. However, it can also be used without prereduction, in which case it is reduced under the conditions of the hydroamination by the hydrogen present in the reactor.

For the pre-reduction, the catalyst is first exposed to a nitrogen-hydrogen atmosphere, preferably at 150-200 deg.C, for a period of, for example, 12-20 hours, and then retreated in a hydrogen atmosphere, preferably at 200-400 deg.C, for up to about 24 hours. In this pre-reduction process, part of the oxygen-containing metal compounds present in the catalyst are reduced to the corresponding metals, and therefore these are present in the active form of the catalyst together with different types of oxygen compounds.

The process according to the invention is carried out continuously, the catalyst preferably being arranged in the reactor in the form of a fixed bed. The flow towards the fixed catalyst bed can be from the top or from the bottom.

The reactant used was MIPOA. There are two different MIPOA structural isomers: 1-aminopropan-2-ol and 2-aminopropan-1-ol. According to the present invention, both isomers can be converted into 1, 2-PDA. Thus, 1-aminopropan-2-ol, 2-aminopropan-1-ol or mixtures of the two isomers may be used. If such a mixture is used, reference to MIPOA in this application always refers to both isomers. MIPOA prepared by reacting propylene oxide with ammonia is preferably used. This gives predominantly 1-aminopropan-2-ol and also small amounts of 2-aminopropan-1-ol, the proportion usually being from 2 to 10% by weight, in particular from 4 to 6% by weight, based on the total mass of the two isomers.

DMDETA prepared according to the present invention is obtained as three different structural isomers. These are N2- (2-aminopropyl) propane-1, 2-diamine, N1- (2-aminopropyl) propane-1, 2-diamine and N2- (2-amino-1-methylethyl) propane-1, 2-diamine.

Ammonia is generally used in a molar amount of from 5 to 30 times, preferably from 6 to 29 times, more preferably from 7 to 28 times, in particular from 8 to 27 times, especially from 9 to 26 times, from 9 to 25 times, from 9 to 20 times or from 9 to 15 times, in each case based on the MIPOA used.

Preference is given to using ammonia (compressed gas, purity in particular 95 to 100% by weight) in the absence of other solvents.

The reactant MIPOA is preferably used in a purity of 95 to 100% by weight, in particular 98 to 100% by weight.

Preferably, 1 to 450 standard cubic meters/[ m ] are used³Catalyst (bed volume). h]In particular 2-200 standard cubic meters/[ m ]³Catalyst (bed volume). h]The volume of exhaust gas of (a). [ Standard cubic meter ═ volume converted to standard conditions (20 ℃, 1 bar absolute)]. The reported catalyst volume is always related to the bed volume.

The amination of the alcohol group of the reactant MIPOA is carried out in the liquid phase. Fixed bed processes are preferred.

When carried out in the liquid phase, the reactants (MIPOA, ammonia) are passed, preferably simultaneously, over a catalyst, which is usually located in a fixed-bed reactor preferably heated from the outside, in the liquid phase at a pressure of from 60 to 170 bar, preferably from 70 to 145 bar, more preferably from 80 to 140 bar, more preferably from 90 to 135 bar, particularly preferably from 100 to 130 bar, for example from 110 to 125 bar and at a temperature of from 120-.

The temperature is chosen such that there is a certain conversion of MIPOA at a given pressure. The reaction is generally present in a conversion of from 70 to 100%, preferably from 80 to 99.9%, likewise preferably from 82 to 99.5%. The conversion was calculated as follows:

wherein n is the residual molar amount of MIPOA after completion of the reaction and n₀Is the original molar amount of MIPOA before the start of the reaction. The molar amount can be determined by gas chromatography, for example as described in the examples section of the present application.

When carried out in the liquid phase, both trickle and liquid phase modes are possible. The liquid phase mode is preferred. The catalyst hourly space velocity is generally in the range from 0.1 to 0.7, preferably from 0.15 to 0.6, particularly preferably from 0.2 to 0.5kg of MIPOA per liter of catalyst (bed volume) and per hour (MIPOA in 100% by weight). The reactants may optionally be passed through a suitable solvent such as water, tetrahydrofuran, dioxaneDiluting with alkyl, N-methyl pyrrolidone or ethylene glycol dimethyl ether. The reactants are preferably not diluted with a solvent, i.e. the reaction according to the invention is carried out without a solvent. It is advantageous to heat the reactants, preferably to the reaction temperature, even before they are fed to the reaction vessel.

The reaction is carried out in the presence of from 1.0 to 4.5% by weight of hydrogen, in particular from 1.2 to 4.5% by weight of hydrogen, more particularly from 1.5 to 4.0% by weight of hydrogen, very particularly from 2.0 to 4.0% by weight of hydrogen, and very particularly from 2.5 to 3.7% by weight of hydrogen, based in each case on the amount of MIPOA used.

The pressure in the reaction vessel, which results from the sum of the partial pressures of ammonia, MIPOA and the reaction products formed and any additionally used solvent at the indicated temperatures, is advantageously increased to the desired reaction pressure (absolute pressure) by injection of hydrogen. All pressure descriptions given herein refer to absolute pressures, unless explicitly stated otherwise.

In addition, excess ammonia may be recycled with the hydrogen.

If the catalyst is arranged in the form of a fixed bed, it may be advantageous for the selectivity of the reaction to mix the shaped catalyst bodies in the reactor with inert random packings, so to speak "dilute". The proportion of random filler in such catalyst preparations may be from 20 to 80 parts by volume, in particular from 30 to 60 parts by volume, especially from 40 to 50 parts by volume.

The reaction water formed during the reaction (in each case 1 mole per mole of alcohol groups converted) generally has no harmful effect on the degree of conversion, the reaction rate, the selectivity and the catalyst life and is therefore only expediently removed from the reaction product (for example by distillation) when working up the reaction product.

The product from the reaction of the present invention may be further worked up. The reaction is generally carried out in a reactor, the output of which, after it has optionally advantageously been depressurized to remove excess hydrogen, is separated by distillation, with

(1) The reactor output is fed to a first distillation column K1, in which ammonia is removed from the side draw or from the top,

(2) the bottom output from K1 is fed to a second distillation column K2, in which water is removed from the side offtake or the top,

(3) the bottom output from K2 is fed to a third distillation column K3, in which 1,2-PDA is removed from the side or overhead,

(4) the bottom output from K3 is fed to a fourth distillation column K4, in which DMDETA is removed at the bottom, MIPOA is removed from the side cut, and low boilers are removed from the top.

The ammonia, water and 1,2-PDA are preferably each removed overhead.

The reactant MIPOA is preferably removed in gaseous form. The side draw is preferably located in the stripping section of K4.

In K4, low boilers (e.g. piperazine, in particular dimethylpiperazine) are generally removed from the top of the column. Low boilers are understood to be those organic components which, under the given distillation conditions (pressure and temperature), have a boiling point which is lower than that of 2-aminopropan-1-ol or 1-aminopropan-2-ol, depending on which of the two has a lower boiling point under the given distillation conditions. The low boilers are in particular organic components with a boiling point of <159 ℃ (1.013 bar).

The ammonia obtained in step (1) and/or the MIPOA obtained in step (4) may be recycled to the reactor. Preferably, both are recycled.

The ammonia removed in step (1) is recycled to the reaction, in particular with a purity of from 90 to 99.9% by weight, more in particular from 95 to 99.9% by weight, wherein in a particular embodiment a portion of the removed ammonia, in particular from 1 to 30% by weight of the removed ammonia, more in particular from 2 to 20% of the removed ammonia, is discharged.

The 1,2-PDA obtained in step (3) usually has a purity of 90 to 99.98% by weight, in particular 95 to 99.9% by weight.

The MIPOA removed in step (4) is recycled to the reaction, in particular with a purity of 90 to 99.9 wt.%, more in particular of 95 to 98 wt.%.

The DMDETA removed in step (4) typically has a purity of 90 to 99.9 wt.%, particularly 94 to 97.5 wt.%.

The top pressure in K1 is preferably from 10 to 25 bar, particularly preferably from 15 to 20 bar, very particularly preferably from 17 to 19 bar. The top temperature is preferably from 20 to 70 ℃, particularly preferably from 30 to 60 ℃ and very particularly preferably from 40 to 50 ℃. The bottom temperature is preferably 180 ℃ and 250 ℃, particularly preferably 190 ℃ and 240 ℃, very particularly preferably 200 ℃ and 230 ℃.

The top pressure in K2 is preferably from 0.3 to 2.5 bar, particularly preferably from 0.5 to 2 bar, very particularly preferably from 1 to 1.5 bar. The top temperature is preferably from 80 to 150 ℃, particularly preferably from 90 to 130 ℃ and very particularly preferably 100 ℃ and 120 ℃. The bottom temperature is preferably 100-.

The top pressure in K3 is preferably from 0.1 to 3 bar, particularly preferably from 0.4 to 2 bar, very particularly preferably from 0.5 to 1.5 bar. The top temperature is preferably from 20 to 200 ℃, particularly preferably from 50 to 190 ℃ and very particularly preferably from 80 to 150 ℃. The bottom temperature is preferably 100-.

The top pressure in K4 is preferably from 0.1 to 3 bar, particularly preferably from 0.3 to 1.5 bar, very particularly preferably from 0.5 to 1 bar. The top temperature is preferably from 80 to 200 ℃, particularly preferably from 100 ℃ to 190 ℃ and very particularly preferably from 120 ℃ to 170 ℃. The bottom temperature is preferably 100-.

In a further distillation stage (step (5)), the DMDETA removed in the bottom of the distillation column K4 can be fed to a fifth distillation column K5, in which the DMDETA having a reduced APHA color number is removed from the top of the column. The distillation in K5 is preferably in the presence of additives for improving the APHA color number, such as NaBH₄Or in the presence of a phosphonic acid.

The DMDETA thus prepared generally has an APHA color number of ≦ 20, in particular ≦ 15, very particularly ≦ 10, for example from 2 to 8.

The APHA color number is determined in accordance with DIN EN 1557.

Suitable distillation columns K1 to K5 include all possible column types known to the person skilled in the art. Preference is given to packed columns having structured or random packing and tray columns having trays such as sieve trays, bubble cap trays or valve trays.

Such distillation methods for the preparation of 1,2-PDA and DMDETA are not described in the prior art. In particular, the following advantages arise, which are surprising to the person skilled in the art. DMDETA having a high purity can be produced by means of the fourth distillation column K4. DMDETA having the above-mentioned purity and formed as a by-product in the preparation of 1,2-PDA is not described at all in the prior art. Further surprising advantages arise in terms of recycling of MIPOA. For example, no accumulation of by-products (e.g., methyl or dimethylpiperazine) has been found. Therefore, it is not necessary to reject a portion of the MIPOA that is preferably present in the above-mentioned purity. This constitutes a significant economic advantage, since the removed MIPOA can thus be completely recycled into the reaction.

FIG. 1 shows a particular embodiment of the process of the invention, in which 1,2-PDA and DMDETA are obtained via a 4-column interconnect.

The following examples serve to illustrate the invention without limiting it in any way.

Examples

The catalyst was produced according to example B3 of WO2013/072289a 1.

Description of the experiments:

as a result:

the results for each molar ratio of ammonia to MIPOA are given in tables 1 and 2.