DE10359811A1 - A method for increasing the space-time yield (RZA) in a process for preparing a symmetrical secondary amine - Google Patents

Abstract

A method for increasing the space-time yield (RZA) in a process for producing a symmetrical secondary amine by reacting a primary amine in the presence of hydrogen and a catalyst at a temperature in the range of 50 to 250 ° C and an absolute pressure in the range of 5 to 350 bar, by lowering the absolute pressure while maintaining the temperature.

Description

The present invention relates to a process for increasing the space-time yield (RZA) in a process for the preparation of a symmetrical secondary amine (R-NH-R; 'symmetrical' expressing that the two radicals R are the same) by reaction a primary amine (R-NH ₂ ).

symmetrical secondary Amines can by catalytic amination of corresponding alcohols, aldehydes or ketones with appropriate primary amines with release of one molar equivalent Water are produced.

Also known are processes for the preparation of symmetrical secondary amines from primary amines by dimerization of the primary amine in the presence of H ₂ under NH ₃ formation according to: 2 R-NH ₂ + H ₂ → R-NH-R + NH ₃ .

The Dimerization of primary Amines, especially from primary linear diamines, e.g. 1,2-ethylenediamine (EDA), on transition metal catalysts to corresponding symmetrical secondary amines, suffers from a Variety of secondary products and side reactions. These are just undesirable in the field of diamines cyclic products such as piperazine (PIP) and piperazine derivatives, but also higher linear products. As a rule, it is based on metallic amination catalysts (e.g., Ni, Co, Cu) at elevated Temperature and under pressure. As examples are the Dimerization (Conversion) of Ethylenediamine (EDA) to Diethylenetriamine (DETA) and the dimerization of 3- (N, N-dimethylamino) propylamine (DMAPA) to bis [(3-dimethylamino) propyl] amine (BisDMAPA).

EP-A1-1 270 543 (BASF AG) describes a process for the preparation of certain secondary amines from primary Amines in the presence of hydrogen and a catalyst, the at least one element or compound of an element contains groups VIII and IB of the periodic table.

The reaction of EDA with transition metal catalysts with itself under a hydrogen atmosphere is known, for example, on Ni-containing catalysts and takes place, for example, at 140-210 [deg.] C. [GB-A-1,508,460 (BASF AG); US 4,568,746 (UCC)]. The reaction is usually carried out only to a partial conversion (10-50%), since the diethylenetriamine formed preferably reacts with prolonged residence time to the thermodynamically preferred piperazine and piperazine derivatives and open-chain higher compounds. The representation succeeds in a wide temperature and pressure range (20-300 bar) on a variety of transition metal-containing catalysts. To increase the overall yield of the process, the use of high metal contents in the catalyst and the use of selectivity- and activity-increasing promoters (eg Ru, Re, Pd, Pt) was investigated: US 3,714,259 . US 4,568,746 WO-A-01/66247, WO-A-03/010125.

By Use of high-percentage Ni-containing catalysts (up to 65%) the EDA conversion can be carried out under milder conditions and so the formation of undesirable By-products and secondary products are lowered (WO-A-03/010125).

To control the DETA / PIP ratio US 5,410,086 (Burgess) the control by adjusting the hydrogen concentration in the liquid phase. It is described that increasing the concentration of hydrogen in the liquid phase increases the ratio of DETA to piperazine, so that a larger proportion of the desired linear product is formed. An increase in the pressure (of the H ₂ partial pressure) should therefore lead to an increase in the H ₂ content in the liquid phase and thus to an improvement in the DETA / PIP ratio.

The Dimerization of DMAPA to bisDMAPA is also described a series of Ni-containing catalysts (e.g., DE-A-101 29 908). The formation of higher linear or cyclic by-products is blocked in this case through the tertiary Amine function of the educt. Therefore, this implementation can generally be found in higher sales to BisDMAPA performed and the by-product spectrum is much less complex than that of the reaction of ethylene amines.

The German Patent Application No. 10261195.5 dated 20.12.02 (BASF AG) a process for producing a symmetrical secondary amine by implementing a primary Amines in the presence of hydrogen and a catalyst, wherein one uses a catalyst, in its production a precipitation of catalytically active components on monoclinic, tetragonal or cubic zirconia.

Controlled So far, such processes have had the choice of sales and product selectivity the reaction temperature, the catalyst composition and catalyst loading, the hydrogen content or the residence time. Furthermore, some procedural Particularities published, such as the use of temperature graded Reactors for avoiding secondary products (for example: EP-A-1 044 183, EP-A-197 611).

For the known processes and catalyst systems for the synthesis of secondary amines from the corresponding primary amines (dimerization) it is known that
that (usually) the conversion should be increased at a given load by increasing the temperature in the reactor,
that, as a rule, in the case of increased conversion (for example in the case of an increase in temperature), the proportion of undesirable secondary components increases as a result of decreasing selectivity of the catalyst,
that usually by raising the burden of sales can be lowered and
that usually by lowering the conversion, the selectivity of the catalyst system increases.

It is an object of the present invention to overcome the disadvantages of the prior art and to provide an improved economical process for the preparation of symmetrical secondary amines. The process should have an increased space-time yield [product amount / (catalyst volume · time)] (kg / (l _cat. · H)) and / or mass-time yield [product amount / (catalyst mass · time)] (kg / (kg _cat. · h)), thereby increasing the conversion of starting material and reduce the catalyst costs by smaller amounts of catalyst, and thus allow in comparison the use of smaller and simpler and also less expensive reactors.

Accordingly, became a method of increase the space-time yield (RZA) in a process for preparation a symmetrical secondary Amines by implementing a primary Amines in the presence of hydrogen and a catalyst at one Temperature in the range of 50 to 250 ° C and an absolute pressure in the Range from 5 to 350 bar found by keeping under retention the temperature decreases the absolute pressure.

According to the invention, it was recognized which dependence of the space-time yield (RZA) or mass-time yield (MZA) on the pressure in the reactor at a constant temperature in the implementation of a primary amine in the presence of hydrogen and a catalyst under NH ₃ Cleavage to the corresponding symmetrical secondary amine (dimerization) is present.

It was found to be at constant pressure when the pressure decreased Temperature an increase in the space-time yield or mass-time yield to achieve.

According to the invention the increase independent of the RZA of whether the conversion takes place at constant sales (by adjustment the weight-hourly-space-velocity (WHSV)) or without adaptation of the WHSV is operated at varying sales and selectivity ratios.

According to the invention was realized that the increase the space-time yield at constant temperature by lowering of the pressure possible is because the decrease in selectivity compensated by the increase in sales becomes.

in the Generally, according to the inventive method while maintaining the temperature, the absolute pressure (e.g., measured in bar) by 10 to 98%, especially 20 to 95%, especially 40 to 95%, especially 60 to 95%, particularly preferably 80 to 95%, decreased.

Under "Retention the temperature "is to understand that, in comparison, the mean temperature in the reactor essentially, i. +/- 0 to 10%, in particular +/- 0 up to 5%, especially +/- 0 up to 2%.

Absolute pressure is the absolute measured pressure in the reactor, which results from the sum of the partial pressures of the reaction components [H ₂ , NH ₃ (product by cleavage), amines, if necessary, solvent].

According to the invention, in the process for preparing a symmetrical secondary amine increase the space-time yield (RZA) by up to 5%, e.g. by 2-5%, in particular up to 10%, e.g. by 6-10%, especially up to 15%, e.g. around 11-15%, (in each case based on the primary amine used) can be achieved.

in der
R¹ Alkyl, wie C_1-200-Alkyl, Cycloalkyl, wie C_3-12-Cycloalkyl, Hydroxyalkyl, wie C_1-20-Hydroxyalkyl, Aminoalkyl, wie C_1-20 -Aminoalkyl, Hydroxyalkylaminoalkyl, wie C_2-20-Hydroxyalkylaminoalkyl, Alkoxyalkyl, wie C_2-30-Alkoxyalkyl, Dialkylaminoalkyl, wie C_3-30-Dialkylaminoalkyl, Alkylaminoalkyl, wie C_2-30-Alkylaminoalkyl, Aryl, Heteroaryl, Aralkyl, wie C_7-20-Aralkyl, Heteroarylalkyl, wie C_2-40-Heteroarylalkyl, Alkylaryl, wie C_7-20-Alkylaryl, Alkylheteroaryl, wie C_4-20-Alkylheteroaryl, oder R³R⁴N-A-, mit A = C_1-6-Alkylen oder -CH₂-CH₂-O-(CH₂-CH₂-O)_n-CH₂-CH₂- (mit n = 0, 1 oder 2) und R³, R⁴ = C_1-4-Alkyl oder gemeinsam mit dem N-Atom, an das sie gebunden sind, einen Piperidin- oder Morpholinring bildend,
bedeutet,
oder die beiden Reste R¹ gemeinsam -(CH₂)_l-CH₂-X-(CH₂)_m-, mit
X CH₂, CHR⁵, Sauerstoff (O), Schwefel (S) oder NR⁵,
R⁵ Wasserstoff (H), Alkyl, wie C_1-4-Alkyl, Alkylphenyl, wie C_{7- 40}-Alkylphenyl,
l, m eine ganze Zahl von 1 bis 4,
bedeuten, durch Umsetzung eines entsprechenden primären Amins der Formel II oder IIa R¹NH₂ (II), H₂N-(CH₂)_l-CH₂-X-(CH₂)_m-NH₂ (IIa). The process according to the invention is preferably used for the preparation of a symmetrical secondary amine of the formula I.

in the
R ^{1 is} alkyl, such as C _1-200 -alkyl, cycloalkyl, such as C _3-12 -cycloalkyl, hydroxyalkyl, such as C _1-20 -hydroxyalkyl, aminoalkyl, such as C _1-20 -aminoalkyl, hydroxyalkylaminoalkyl, such as C _2-20 - Hydroxyalkylaminoalkyl, alkoxyalkyl such as C _2-30 alkoxyalkyl, dialkylaminoalkyl such as C _3-30 dialkylaminoalkyl, alkylaminoalkyl such as C _2-30 alkylaminoalkyl, aryl, heteroaryl, aralkyl such as C _7-20 aralkyl, heteroarylalkyl such as C _2-40 heteroarylalkyl, alkylaryl, such as C _7-20 alkylaryl, alkylheteroaryl, such as C _4-20 alkyl heteroaryl, or R ³ R ⁴ NA-, with A = C _1-6 alkylene or -CH ₂ -CH ₂ -O- (CH ₂ -CH ₂ -O) _n -CH ₂ -CH ₂ - (with n = 0, 1 or 2) and R ³ , R ⁴ = C _1-4 -alkyl or together with the N-atom to which they are attached, forming a piperidine or morpholine ring,
means
or the two radicals R ¹ together - (CH ₂ ) ₁ -CH ₂ -X- (CH ₂ ) _m -, with
X is CH ₂ , CHR ⁵ , oxygen (O), sulfur (S) or NR ⁵ ,
R ⁵ is hydrogen (H), alkyl, such as C _1-4 alkyl, alkylphenyl, such as C _{7- 40} alkylphenyl,
l, m is an integer from 1 to 4,
mean, by reacting a corresponding primary amine of formula II or IIa R ¹ NH ₂ (II), H ₂ N- (CH ₂ ) ₁ -CH ₂ -X- (CH ₂ ) _m -NH ₂ (IIa).

• – Alkyl, wie C_1-200-Alkyl, bevorzugt C_1-20-Alkyl, besonders bevorzugt C_1-14-Alkyl, wie Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec.-Butyl, tert.-Butyl, n-Pentyl, iso-Pentyl, sec.-Pentyl, neo-Pentyl, 1,2-Dimethylpropyl, n-Hexyl, iso-Hexyl, sec.-Hexyl, Cyclopentylmethyl, n-Heptyl, iso-Heptyl, Cyclohexylmethyl, n-Octyl, iso-Octyl, 2-Ethylhexyl, n-Decyl, 2-n-Propyl-n-heptyl, n-Tridecyl, 2-n-Butyl-n-nonyl und 3-n-Butyl-n-nonyl, insbesondere C_1-4-Alkyl,
• – Cycloalkyl, wie C_3-12-Cycloalkyl, bevorzugt C_3-8-Cycloalkyl, wie Cyclopropyl, Cyclobutyl, Cyclopentyl, Cyclohexyl, Cyclohentyl und Cyclooctyl, besonders bevorzugt Cyclopentyl und Cyclohexyl,
• – Hydroxyalkyl, wie C_1-20-Hydroxyalkyl, bevorzugt C_1-8-Hydroxyalkyl, besonders bevorzugt C_1-4-Hydroxyalkyl, wie Hydroxymethyl, 1-Hydroxyethyl, 2-Hydroxyethyl, 1-Hydroxy-n-propyl, 2-Hydroxy-n-propyl, 3-Hydroxy-n-propyl und 1-(Hydroxymethyl)ethyl,
• – Aminoalkyl, wie C_1-20-Aminoalkyl, bevorzugt C_1-8-Aminoalkyl, wie Aminomethyl, 2-Aminoethyl, 2-Amino-1,1-dimethylethyl, 2-Amino-n-propyl, 3-Amino-n-propyl, 4-Amino-n-butyl, 5-Amino-n-pentyl, N-(2-Aminoethyl)-2-aminoethyl und N-(2-Aminoethyl)aminomethyl,
• – Hydroxyalkylaminoalkyl, wie C_2-20-Hydroxyalkylaminoalkyl, bevorzugt C_3-8-Hydroxyalkylaminoalkyl, wie (2-Hydroxyethylamino)methyl, 2-(2-Hydroxyethylamino)ethyl und 3-(2-Hydroxyethylamino)propyl,
• – Alkoxyalkyl, wie C_2-30-Alkoxyalkyl, bevorzugt C_2-20-Alkoxyalkyl, besonders bevorzugt C_2-8-Alkoxyalkyl, wie Methoxymethyl, Ethoxymethyl, n-Propoxymethyl, iso-Propoxymethyl, n-Butoxymethyl, iso-Butoxymethyl, sec.-Butoxymethyl, tert.-Butoxymethyl, 1-Methoxy-ethyl und 2-Methoxyethyl, besonders bevorzugt C_2-4-Alkoxyalkyl,
• – Dialkylaminoalkyl, wie C_3-30-Dialkylaminoalkyl, bevorzugt C_3-20-Dialkylaminoalkyl, besonders bevorzugt C_3-10-N,N-Dialkylaminoalkyl, wie (N,N-Dimethylamino)methyl, (N,N-Dibutylamino)methyl, 2-(N,N-Dimethylamino)ethyl, 2-(N,N-Diethylamino)ethyl, 2-(N,N-Dibutylamino)ethyl, 2-(N,N-Di-n-propylamino)ethyl, 2-(N,N-Di-iso-propylamino)ethyl, (R⁵)₂N-(CH₂)_l, ganz besonders 3-(N,N-Dimethylamino)propyl
• – Alkylaminoalkyl, wie C_2-30-Alkylaminoalkyl, bevorzugt C_2-20-Alkylaminoalkyl, besonders bevorzugt C_2-8-Alkylaminoalkyl, wie Methylaminomethyl, 2-(Methylamino)ethyl, Ethylaminomethyl, 2-(Ethylamino)ethyl und 2-(iso-Propylamino)ethyl, (R⁵)HN-(CH₂)_q (q = 1 bis 6),
• – Aryl, wie Phenyl, 1-Naphthyl, 2-Naphthyl, 1-Anthryl, 2-Anthryl und 9-Anthryl, bevorzugt Phenyl, 1-Naphthyl und 2-Naphthyl, besonders bevorzugt Phenyl,
• – Heteroaryl, wie 2-Pyridinyl, 3-Pyridinyl, 4-Pyridinyl, Pyrazinyl, Pyrrol-3-yl, Imidazol-2-yl, 2-Furanyl und 3-Furanyl,
• – Aralkyl, wie C_7-20-Aralkyl, bevorzugt C_7-12-Phenylalkyl, wie Benzyl, p-Methoxybenzyl, 3,4-Dimethoxybenzyl, 1-Phenethyl, 2-Phenethyl, 1-Phenyl-propyl, 2-Phenylpropyl, 3-Phenyl-propyl, 1-Phenyl-butyl, 2-Phenyl-butyl, 3-Phenyl-butyl und 4-Phenyl-butyl, besonders bevorzugt Benzyl, 1-Phenethyl und 2-Phenethyl,
• – Heteroarylalkyl, wie C_4-20-Heteroarylalkyl, wie Pyrid-2-yl-methyl, Furan-2-yl-methyl, Pyrrol-3-yl-methyl und Imidazol-2-yl-methyl,
• – Alkylaryl, wie C_7-20-Alkylaryl, bevorzugt C_7-12-Alkylphenyl, wie 2-Methylphenyl, 3-Methylphenyl, 4-Methylphenyl, 2,4-Dimethylphenyl, 2,5-Dimethylphenyl, 2,6-Dimethylphenyl, 3,4-Dimethylphenyl, 3,5-Dimethylphenyl, 2,3,4-Trimethylphenyl, 2,3,5-Trimethylphenyl, 2,3,6-Trimethylphenyl, 2,4,6-Trimethylphenyl, 2-Ethylphenyl, 3-Ethylphenyl, 4-Ethylphenyl, 2-n-Propylphenyl, 3-n-Propylphenyl und 4-n-Propylphenyl,
• – Alkylheteroaryl, wie C_4-20-Alkylheteroaryl, wie 2-Methyl-3-pyridinyl, 4,5-Dimethyl-imidazol-2-yl, 3-Methyl-2-furanyl und 5-Methyl-2-pyrazinyl,
• – R³R⁴N-A-, mit A = C_1-6-Alkylen (wie -CH₂-CH₂-, -CH₂-CH₂-CH₂-, -CH₂-CH₂-CH₂-CH₂-) oder -CH₂-CH₂-O-(CH₂-CH₂-O)_n-CH₂-CH₂- (mit n = 0, 1 oder 2) und R³, R⁴ = C_1-4-Alkyl (wie oben für R¹ definiert) oder gemeinsam mit dem N-Atom, an das sie gebunden sind, einen Piperidin- oder Morpholinring bildend,
• – oder beide Reste bedeuten gemeinsam eine -(CH₂)_l-CH₂-X-(CH₂)_m Gruppe, wie -(CH₂)₄-, -(CH₂)₅-, -(CH₂)₆-, -(CH₂)₇-, -(CH₂)-O-(CH₂)₂-, -(CH₂)-NR⁵-(CH₂)₂-, -(CH₂)-CHR⁵-(CH₂)₂-, -(CH₂)₂-O-(CH₂)₂-, -(CH₂)₂-NR⁵-(CH₂)₂-, -(CH₂)₂-CHR⁵ (CH₂)₂-, -CH₂-O-(CH₂)₃-, -CH₂-NR⁵-(CH₂)₃-,

R⁵:

• – Wasserstoff (H),
• – Alkyl, besonders C_1-4-Alkyl, wie Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec.-Butyl und tert.-Butyl, bevorzugt Methyl und Ethyl, besonders bevorzugt Methyl,
• – Alkylphenyl, besonders C_7-40-Alkylphenyl, wie 2-Methylphenyl, 3-Methylphenyl, 4-Methylphenyl, 2,4-Dimethylphenyl, 2,5-Dimethylphenyl, 2,6-Dimethylphenyl, 3,4-Dimethylphenyl, 3,5-Dimethylphenyl, 2-, 3-, 4-Nonylphenyl, 2-, 3-, 4-Decylphenyl, 2,3-, 2,4-, 2,5-, 3,4-, 3,5-Dinonylphenyl, 2,3-, 2,4-, 2,5-, 3,4- und 3,5-Didecylphenyl,

X:

• – CH₂, CHR⁵, Sauerstoff (O), Schwefel (S) oder NR⁵, bevorzugt CH₂, NH und O,

l:

• – eine ganze Zahl von 1 bis 4 (1, 2, 3 oder 4), bevorzugt 1 und 2,

m:

• – eine ganze Zahl von 1 bis 4 (1, 2, 3 oder 4), bevorzugt 1 und 2,

The substituents R ¹ , R ³ to R ⁵ , the variable X and the indices I, m in the compounds I, II and IIa have, independently of one another, the following meanings:
R ¹ :

• Alkyl, such as C _1-200 -alkyl, preferably C _1-20 -alkyl, more preferably C _1-14 -alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec Butyl, tert-butyl, n-pentyl, iso-pentyl, sec-pentyl, neo-pentyl, 1,2-dimethylpropyl, n-hexyl, iso-hexyl, sec-hexyl, cyclopentylmethyl, n-heptyl , isoheptyl, cyclohexylmethyl, n-octyl, isooctyl, 2-ethylhexyl, n-decyl, 2-n-propyl-n-heptyl, n-tridecyl, 2-n-butyl-n-nonyl and 3-n Butyl-n-nonyl, in particular C _1-4 -alkyl,
• Cycloalkyl, such as C _3-12 -cycloalkyl, preferably C _3-8 -cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohentyl and cyclooctyl, more preferably cyclopentyl and cyclohexyl,
• Hydroxyalkyl, such as C _1-20 -hydroxyalkyl, preferably C _1-8 -hydroxyalkyl, more preferably C _1-4 -hydroxyalkyl, such as hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, 1-hydroxy-n-propyl, 2-hydroxy n-propyl, 3-hydroxy-n-propyl and 1- (hydroxymethyl) ethyl,
• Aminoalkyl, such as C _1-20 -aminoalkyl, preferably C _1-8 -aminoalkyl, such as aminomethyl, 2-aminoethyl, 2-amino-1,1-dimethylethyl, 2-amino-n-propyl, 3-amino-n- propyl, 4-amino-n-butyl, 5-amino-n-pentyl, N- (2-aminoethyl) -2-aminoethyl and N- (2-aminoethyl) aminomethyl,
• Hydroxyalkylaminoalkyl, such as C _2-20 -hydroxyalkylaminoalkyl, preferably C _3-8 -hydroxyalkylaminoalkyl, such as (2-hydroxyethylamino) methyl, 2- (2-hydroxyethylamino) ethyl and 3- (2-hydroxyethylamino) propyl,
• Alkoxyalkyl, such as C _2-30 -alkoxyalkyl, preferably C _2-20 -alkoxyalkyl, particularly preferably C _2-8 -alkoxyalkyl, such as methoxymethyl, ethoxymethyl, n-propoxymethyl, isopropoxymethyl, n-butoxymethyl, isobutoxymethyl, sec Butoxymethyl, tert-butoxymethyl, 1-methoxy-ethyl and 2-methoxyethyl, more preferably C _2-4 -alkoxyalkyl,
• Dialkylaminoalkyl, such as C _3-30 -dialkylaminoalkyl, preferably C _3-20 -dialkylaminoalkyl, particularly preferably C _3-10 -N, N-dialkylaminoalkyl, such as (N, N-dimethylamino) methyl, (N, N-dibutylamino) methyl , 2- (N, N-Dimethylamino) ethyl, 2- (N, N -diethylamino) ethyl, 2- (N, N -dibutylamino) ethyl, 2- (N, N-di-n-propylamino) ethyl, 2 - (N, N-di-iso -propylamino) ethyl, (R ⁵ ) ₂ N- (CH ₂ ) ₁ , especially 3- (N, N-dimethylamino) propyl
• Alkylaminoalkyl, such as C _2-30 -alkylaminoalkyl, preferably C _2-20 -alkylaminoalkyl, more preferably C _2-8 -alkylaminoalkyl, such as methylaminomethyl, 2- (methylamino) ethyl, ethylaminomethyl, 2- (ethylamino) ethyl and 2- ( iso-propylamino) ethyl, (R ⁵ ) HN- (CH ₂ ) _q (q = 1 to 6),
• Aryl, such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl and 9-anthryl, preferably phenyl, 1-naphthyl and 2-naphthyl, more preferably phenyl,
• Heteroaryls such as 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, pyrazinyl, pyrrol-3-yl, imidazol-2-yl, 2-furanyl and 3-furanyl,
• Aralkyl, such as C _7-20 aralkyl, preferably C _7-12 phenylalkyl, such as benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, 1-phenethyl, 2-phenethyl, 1-phenyl-propyl, 2-phenylpropyl, 3-phenyl-propyl, 1-phenyl-butyl, 2-Phe nyl-butyl, 3-phenyl-butyl and 4-phenyl-butyl, more preferably benzyl, 1-phenethyl and 2-phenethyl,
• Heteroarylalkyl, such as C _4-20 heteroarylalkyl, such as pyrid-2-ylmethyl, furan-2-ylmethyl, pyrrol-3-ylmethyl and imidazol-2-ylmethyl,
• Alkylaryl, such as C _7-20 -alkylaryl, preferably C _7-12 -alkylphenyl, such as 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,3,4-trimethylphenyl, 2,3,5-trimethylphenyl, 2,3,6-trimethylphenyl, 2,4,6-trimethylphenyl, 2-ethylphenyl, 3 Ethylphenyl, 4-ethylphenyl, 2-n-propylphenyl, 3-n-propylphenyl and 4-n-propylphenyl,
• Alkylheteroaryl, such as C _4-20 -alkyl heteroaryl, such as 2-methyl-3-pyridinyl, 4,5-dimethyl-imidazol-2-yl, 3-methyl-2-furanyl and 5-methyl-2-pyrazinyl,
• R ³ R ⁴ NA-, with A = C _1-6 -alkylene (such as -CH ₂ -CH ₂ -, -CH ₂ -CH ₂ -CH ₂ -, -CH ₂ -CH ₂ -CH ₂ -CH ₂ -) or -CH ₂ -CH ₂ -O- (CH ₂ -CH ₂ -O) _n -CH ₂ -CH ₂ - (with n = 0, 1 or 2) and R ³ , R ⁴ = C _1-4 -Alkyl (as defined above for R ¹ ) or together with the N-atom to which they are attached, forming a piperidine or morpholine ring,
• Or both radicals together represent a - (CH ₂ ) ₁ -CH ₂ -X- (CH ₂ ) _m group, such as - (CH ₂ ) ₄ -, - (CH ₂ ) ₅ -, - (CH ₂ ) ₆ - , - (CH ₂ ) ₇ -, - (CH ₂ ) -O- (CH ₂ ) ₂ -, - (CH ₂ ) -NR ⁵ - (CH ₂ ) ₂ -, - (CH ₂ ) -CHR ⁵ - ( CH ₂ ) ₂ -, - (CH ₂ ) ₂ -O- (CH ₂ ) ₂ -, - (CH ₂ ) ₂ -NR ⁵ - (CH ₂ ) ₂ -, - (CH ₂ ) ₂ -CHR ⁵ (CH ₂ ) ₂ -, -CH ₂ -O- (CH ₂ ) ₃ -, -CH ₂ -NR ⁵ - (CH ₂ ) ₃ -,

R ^5:

• - hydrogen (H),
• - Alkyl, especially C _1-4 alkyl, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl and tert-butyl, preferably methyl and ethyl, particularly preferably methyl .
• Alkylphenyl, especially C _7-40 -alkylphenyl, such as 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3, 5-dimethylphenyl, 2-, 3-, 4-nonylphenyl, 2-, 3-, 4-decylphenyl, 2,3-, 2,4-, 2,5-, 3,4-, 3,5-dinonylphenyl, 2,3-, 2,4-, 2,5-, 3,4- and 3,5-didecylphenyl,

X:

• - CH ₂ , CHR ⁵ , oxygen (O), sulfur (S) or NR ⁵ , preferably CH ₂ , NH and O,

l:

• An integer from 1 to 4 (1, 2, 3 or 4), preferably 1 and 2,

m:

• An integer from 1 to 4 (1, 2, 3 or 4), preferably 1 and 2,

The primary amines which can be used in the process according to the invention can be straight-chain (linear), branched or cyclic. With regard to the carbon number of the primary amines, there are practically no restrictions. The primary amines may further bear substituents or contain functional groups which are inert under the conditions of dimerization to the symmetrical secondary amine under NH ₃ formation, for example hydroxy, alkoxy, alkylamino or dialkylamino groups, or optionally also hydrogenated under the conditions For example, aliphatic (ie, non-aromatic) C-C double bonds and C-C triple bonds.

For example, the following primary amines are preferably used in the process according to the invention:
1,2-ethylenediamine (EDA) (conversion to diethylenetriamine (DETA),
3- (dimethylamino) propylamine (DMAPA) (conversion to bis [(3-dimethylamino) -propyl] amine (bis-DMAPA),
1,3-propanediamine (conversion to corresponding oligomer or polymer).

The inventive method is generally at temperatures of 50 to 250 ° C, preferably at 90 to 200 ° C, more preferably at 140 to 170 ° C, and absolute pressures of 5 up to 350 bar, preferably 5 to 200 bar, particularly preferably 10 up to 100 bar, in particular 20 to 60 bar, discontinuously or preferably continuously in pressure equipment such as autoclaves or preferably carried out tubular reactors. Of the Pressure is preferably over set the amount of hydrogen in the reactor. When using a tubular reactor the catalyst used may also be present as a fixed bed catalyst.

The Reaction can be in the gas phase or in the gas / liquid phase respectively.

The catalyst loading, based on the primary amine used, is preferably 0.1 to 2 kg I _cat. ^-1 h ^-1 , in particular 0.8 to 1.2 kg I _cat. ^-1 h ^-1 . (I _cat. = Catalyst bulk volume in liters).

It can be a part of the liquid or gaseous Be discharged reaction in the implementation.

The inventive method let yourself solventless or in solvents such as. Water, methanol, ethanol, tetrahydrofuran (THF), methyl tert-butyl ether (MTBE) or N-methylpyrrolidone (NMP). In the solvent can thereby used primary Amine dissolved be. The solvent can also be fed separately to the reactor at any point. Preferably, it becomes solvent-free worked.

The with the method according to the invention obtained desired symmetrical secondary Amine leaves in a conventional manner, for example by distillation, from Separate reaction mixture and clean.

For example it is possible in the work-up of the reaction product by Rectification a stream with pure secondary amine and a stream with primary Amine, wherein the current with the primary amine advantageously is attributed to the synthesis.

in the In general, the (unreacted) primary amines fall in the crude reaction product and the symmetrical secondary Amines in a weight ratio from 10: 1 to 1:10, preferably 2: 3-4.

at In the conversion of DMAPA to bis-DMAPA these two amines are included in the Reaction product generally in the weight ratio DMAPA: bis-DMAPA = 0.5-1.5 : 1, e.g. 1: 1, on.

at In the reaction of EDA to DETA, these two amines fall in the reaction product generally in weight ratio EDA: DETA = 50-90: 20, e.g. 70: 20, on. Here is e.g. at a EDA conversion of 30% achieved a DETA selectivity of about 75%.

in the Generally, the reaction crude products of the process according to the invention contain only small amounts of tertiary Amines as reaction by-products (usually in amounts <10 wt .-%, in particular <5 wt .-%, completely especially 0 to 3 wt .-%).

In the process according to the invention, preference is given to using catalysts which comprise a transition metal selected from Ni, Co, Cu, Ru, Re, Rh, Pd and Pt, or a mixture of the elements mentioned on oxidic supports [eg. Alpha-Al ₂ O ₃ , gamma]. Al ₂ O ₃ , delta-Al ₂ O ₃ , theta-Al ₂ O ₃ , TiO ₂ , amorphous or crystalline ZrO ₂ (eg monoclinic, tetragonal, cubic), SiO ₂ ] or mixtures of said support materials.

The catalytically active material used in the process according to the invention Catalysts may further comprise one or more elements (oxidation state 0) or their inorganic or organic compounds selected from Groups IA to VI A and IB to VIIB and VIII of the Periodic Table, contain.

Examples of such elements or their compounds are:
Transition metals, such as Mn or manganese oxides, Re or rhenium oxides, Cr or chromium oxides, Mo or molybdenum oxides, W or tungsten oxides, Ta or tantalum oxides, Nb or niobium oxides or niobium oxalate, V or vanadium oxides or vanadyl pyrophosphate, zinc or Zinc oxides, silver or silver oxides, tin or tin oxides, lanthanides, such as Ce or CeO ₂ or Pr or Pr ₂ O ₃ , alkali metal oxides, such as Na ₂ O, alkali metal carbonates, such as Na ₂ CO ₃ and K ₂ CO ₃ , Alkaline earth metal oxides, such as SrO, alkaline earth metal carbonates, such as MgCO ₃ , CaCO ₃ , BaCO ₃ , phosphoric anhydrides and boron oxide (B ₂ O ₃ ).

The Catalysts can according to known methods, e.g. by precipitation, precipitation, impregnation.

Particularly preferred catalysts contain in their catalytically active composition prior to treatment with hydrogen
20 to 85 wt .-%, preferably 20 to 65 wt .-%, particularly preferably 22 to 40 wt .-%, Al ₂ O ₃ , TiO ₂ , ZrO ₂ and / or SiO ₂ ,
1 to 30 wt .-%, particularly preferably 2 to 25 wt .-%, oxygen-containing compounds of copper, calculated as CuO, and
14 to 70 wt .-%, preferably 15 to 50 wt .-%, particularly preferably 21 to 45 wt .-%, oxygen-containing compounds of nickel, calculated as NiO, wherein preferably the molar ratio of nickel to copper greater than 1, especially greater than 1.2, especially 1.8 to 8.5,

In a further variant, these particularly preferred catalysts additionally contain in their catalytically active composition prior to treatment with hydrogen
15 to 50 wt .-%, particularly preferably 21 to 45 wt .-%, oxygen-containing compounds of cobalt, calculated as CoO.

The oxygenated compounds of copper, nickel and optionally Cobalt, each calculated as CuO, NiO and CoO, the preferred Catalysts are generally in total in amounts of 15 to 80 wt .-%, preferably 35 to 80 wt .-%, particularly preferably 60 to 78 wt .-%, in the catalytically active composition (before treatment with hydrogen), wherein particularly preferably the molar ratio of Nickel to copper is greater than 1.

Further preferred catalysts in the process according to the invention are
in DE-A-19 53 263 (BASF AG) disclosed catalysts containing cobalt, nickel and copper and alumina and / or silica having a metal content of 5 to 80 wt .-%, in particular 10 to 30 wt .-%, based on the total catalyst, wherein the catalysts, calculated on the metal content, 70 to 95 wt .-% of a mixture of cobalt and nickel and 5 to 30 wt .-% copper and wherein the weight ratio of cobalt to nickel 4: 1 to 1: 4 , in particular 2: 1 to 1: 2, for example, the catalyst used in the examples there having the composition 10 wt .-% CoO, 10 wt .-% NiO and 4 wt .-% CuO on Al ₂ O ₃ ,
in EP-A-382 049 (BASF AG) disclosed catalysts whose catalytically active material prior to treatment with hydrogen
From 20 to 85% by weight, preferably from 70 to 80% by weight, of ZrO ₂ ,
From 1 to 30% by weight, preferably from 1 to 10% by weight, of CuO,
and in each case 1 to 40 wt .-%, preferably 5 to 20 wt .-%, CoO and NiO contains, for example, those in loc. cit. 76 wt% Zr calculated as ZrO ₂ , 4 wt% Cu, calculated as CuO, 10 wt% Co, calculated as CoO, and 10 wt% Ni, on page 6 calculated as NiO,
in EP-A-963 975 (BASF AG) disclosed catalysts whose catalytically active material prior to treatment with hydrogen
From 22 to 40% by weight of ZrO ₂ ,
1 to 30% by weight of oxygen-containing compounds of copper, calculated as CuO, 15 to 50% by weight of oxygen-containing compounds of nickel, calculated as NiO, the molar Ni: Cu ratio being greater than 1,
From 15 to 50% by weight of oxygen-containing compounds of cobalt, calculated as CoO, from 0 to 10% by weight of oxygen-containing compounds of aluminum and / or manganese, calculated as Al ₂ O ₃ or MnO ₂ ,
and contains no oxygen-containing compounds of molybdenum,
for example, the one in loc. cit., page 17, disclosed catalyst A having the composition 33 wt% Zr, calculated as ZrO ₂ , 28 wt% Ni, calculated as NiO, 11 wt% Cu, calculated as CuO and 28 wt%. % Co, calculated as CoO,
in EP-A-696 572 (BASF AG) disclosed catalysts whose catalytically active material before reduction with hydrogen 20 to 85 wt .-% ZrO ₂ , 1 to 30 wt .-% oxygen-containing compounds of copper, calculated as CuO, 30 to 70% by weight of oxygen-containing compounds of nickel, calculated as NiO, 0.1 to 5% by weight of oxygen-containing compounds of molybdenum, calculated as MoO ₃ , and 0 to 10% by weight of oxygen-containing compounds of aluminum and / or manganese , calculated as Al ₂ O ₃ or MnO ₂ , contains, for example, in loc. cit., page 8, disclosed catalyst having the composition 31.5 wt% ZrO ₂ , 50 wt% NiO, 17 wt% CuO and 1.5 wt% MoO ₃ ,
in EP A1-1 270 543 (BASF AG), comprising at least one element or a compound of an element from Groups VIII and IB of the Periodic Table,
and
in the German patent application no. 10261195.5 from 20.12.02 (BASF AG) described catalysts, in whose preparation a precipitation of catalytically active components on monoclinic, tetragonal or cubic zirconia took place.

The with the method according to the invention available symmetrical secondary Amines, e.g. To-DMAPA, can can be used as a hardener for epoxy resins, Catalysts for Polyurethanes, intermediates for the preparation of quaternary ammonium compounds, Plasticizers, corrosion inhibitors, textile auxiliaries, dyes and / or emulsifiers.

The symmetrical secondary Amines can Furthermore for the production of synthetic resins, ion exchangers, pharmaceuticals, Crop protection and / or pesticides serve.

Examples

example 1

EDA dimerization (conversion) to DETA

For the conversion from EDA to DETA, the space-time yield was dependent determined by pressure and temperature in such a way that by regulation the WHSV kept the sales and the selectivity in a constant relationship were.

The Implementation of EDA was carried out in a fixed bed reactor, which at different pressures and temperatures could be operated.

The Reaction of EDA was at different pressures between 17 and 200 bar carried out.

The reaction of EDA was carried out in the presence of hydrogen, between 5 and 0.05% by weight of H ₂ (based on EDA).

The catalyst used was the catalyst disclosed in DE-A-19 53 263 (BASF AG) with the composition 10% by weight of CoO, 10% by weight of NiO and 4% by weight of CuO on Al ₂ O ₃ .

to Determination of the space-time yield of secondary amines became the reactor operated at a certain temperature and pressure and over the variation of WHSV regulated an EDA turnover in the range of 28 to 32%.

Temperature - Variation:

to Determination of the space-time yield was at a given pressure the Temperature gradually increased from 150 to 170 ° C and respectively over the Variation of WHSV adjusted sales in the range 28 to 32%. So could be a dependency be determined by the temperature in the reactor at a constant pressure. It turns out that when increasing the temperature at constant pressure to achieve an increase in the space-time yield is.

A increase the reaction rate with temperature increase is generally known.

With Although the increase in conversion decreases the selectivity of the used Catalyst, nevertheless results in an increase in the RZA of the product DETA.

Pressure Variation:

to Determination of the space-time yield was at a given temperature the pressure gradually reduced from 200 to 17 bar (ie by 91.5%) and each about the variation of WHSV regulated sales in the range 28 to 32%.

It it was found that when reducing the pressure of the reactor to increase the WHSV could be driven to sales in the desired To regulate area. The selectivity values obtained in these reactions remained under pressure reduction and sales increase in a range of 73 up to 76% stable.

Out the increase the WHSV at the same time approximate Consistency of sales and selectivity results in an increase the space-time yield of the product.

A graphical representation of the results can be found in the attached Graphics 1 and 2.

Example 2

Conversion (dimerization) from DMAPA to BisDMAPA

The Conversion of DMAPA to bisDMAPA was at different temperatures between 150 and 170 ° C carried out.

The Reaction was at different pressures between 10 and 80 bar carried out.

The reaction was carried out in the presence of hydrogen, between 0.45 and 0.9% by weight of H ₂ (based on EDA).

A catalyst according to DE-A-19 53 263 with the composition 10% by weight of CoO, 10% by weight of NiO and 4% by weight of CuO on Al ₂ O _{3 was used} .

to Determination of the space-time yield was at constant WHSV and Temperature of the pressure gradually reduced from 80 to 10 bar (ie 87.5%) and conversion and selectivity values of the reaction.

The revenues were not regulated to a specific value.

It showed that the space-time yield of the product at reduction to increase the pressure. Primarily the turnover of the reaction increases at decrease of pressure with decrease of selectivity; the RZA as Product of WHSV, sales and selectivity increases with pressure reduction.

Claims (10)

Method for increasing the space-time yield (RZA) in a process for preparing a symmetrical secondary amine by implementing a primary Amines in the presence of hydrogen and a catalyst at one Temperature in the range of 50 to 250 ° C and an absolute pressure in the Range from 5 to 350 bar by keeping the temperature lowered the absolute pressure. The method of claim 1 for increasing the RZA by up to 15%. Process according to claims 1 or 2 for the preparation of bis [(3-dimethylamino) propyl] amine (BisDMAPA) by reaction of 3- (N, N-dimethylamino) propylamine (DMAPA). Process according to claims 1 or 2 for the preparation of diethylenetriamine (DETA) by reaction of ethyleneamine (EDA). Method according to one of the preceding claims, wherein the reaction is carried out at a temperature in the range of 90 to 200 ° C. Method according to one of claims 1 to 4, wherein the reaction at a temperature in the range of 140 to 170 ° C is performed. Method according to one of the preceding claims, wherein while maintaining the temperature, the absolute pressure by 10 to 98% lowered. Method according to one of claims 1 to 6, wherein under Maintaining the temperature lowered the absolute pressure by 20 to 95%. Method according to one of the preceding claims, wherein the average temperature in the reactor is maintained +/- 0 to 10%: Method according to one of the preceding claims, wherein the reaction is carried out in the presence of a catalyst, in its catalytically active composition prior to treatment with hydrogen 20 to 85 wt .-%, Al ₂ O ₃ , TiO ₂ , ZrO ₂ and / or SiO ₂ , 1 to 30 wt .-%, oxygen-containing compounds of copper, calculated as CuO, and 14 to 70 wt .-%, oxygen-containing compounds of the nickel, calculated as NiO contains.