DD217507A1 - PROCESS FOR PREPARING DI AND POLYETHYLENE POLYAMINES - Google Patents

Abstract

A process for the preparation of di- and polyethylenepolyamines in which it is possible by a 2-stage reaction of monoethanolamine on a hydrogenation catalyst in the presence of hydrogen, the ratio between the most important reaction products, such as ethylenediamine, diethylenetriamine, triethylenetetramine, piperazine and Nb- Aminoethylpiperazine depending on the reaction conditions to vary widely. The first stage of the amination of monoethanolamine is carried out in the presence of an excess of ammonia, in which subsequent second stage is a largely freed of ammonia amination of the first stage used. Under mild reaction conditions, a water-clear reaction product is thus obtained, which is virtually free from discoloration and higher molecular weight condensation products.

Description

VEB-.Leuna-Werke Leuna, the

"Walter Ulbricht"

LP 8322 ...

Title of the invention · .- '. , Process for the preparation of di- and polyethylenepolyamines Field of application of the invention

The invention relates to a process for the preparation of di- and polyethylenepolyamines, in particular of diethylenetriamine, by amination of monoethanolamine on a hydrogenation catalyst. . "

Characteristic of the known technical solutions

The preparation of ethylenediamine from monoethanolamine by reaction with ammonia is known. In this amination arise, especially when a high selectivity of Ethylenend'iaminbildung is desired, only small amounts of diethylenetriamine. and higher polyethylenepolyamines (PM Kohn, Chem. Eng. 85 (1978/7), 90 and Ch. M. Barnes et al., Ind. Eng. Chem. Prod. Res. Dev. 20 (1981/2), 399-407) ,

2fiAUG.1983 * il2O5-7

It has therefore already been attempted to obtain higher polyethylenepolyamines, including dithylenetriamine, by the direct reaction of monoethanolamine with ethylenediamine. Thus, US Pat. No. 3,7t4,259 describes a process in which ethylenediamine is reacted with monoethanolamine on a nickel / copper / chromium oxide catalyst in the presence of hydrogen and water to give a mixture of cyclic and linear polyamines. The temperatures of about 425 K possible in these processes for a high dithiethylenitriamine selectivity permit only a low conversion even with long reaction times.

Furthermore, it is / known to implement ethylenediamine with monoethanolamine on BPO, and other phosphorus compounds (US Pat. No. 4,036,881) and on cation exchangers (DS-OS No. 3,127,105). An excess of ethylenediamine is required and for conversions of approx. 50 % , temperatures of at least 575 K are necessary. Ss creates a complex. Reaction mixture whose composition determined by GC does not permit any assessment of the selectivity without specifying the formation of high molecular weight products which is customary in such reaction temp era doors.

U.S. Pat. Nos. 4,316,840 and 4,316,841 disclose the conversion of ethylenediamine to higher polyamines, which are predominantly cyclic (piperazine, IT-.beta.-aminoethylpiperazine), and the reaction requires as catalysts either beryllium salts or freshly precipitated BPO, and also temperatures above 575 K. Sine economical. Use of these methods is excluded by the product range and the reaction conditions.

All previously known processes for the preparation of higher polyethylenepolyamines require pure ethylenediamine, usually in excess, in addition to monoethanolamine as the starting material. The reaction gives in all cases a reaction mixture which corresponds in its qualitative composition to that in the amination of monoethanolamine with ammonia. About that

In addition, the predominantly used high reaction temperatures lead to a significant thermal decomposition of amines and hydroxyamines, so that permanently discolored reaction products mit.einem a high proportion of undefined and polymeric substances are formed. _f

Object of the invention

The aim of the invention is to develop an economical process for the preparation of preferably higher polyethylenepolyamines, based on polyunanolamine without the use of ethylenediamine as the pure substance, whose reaction product can be worked up in a known manner without additional measures for the decolorization of the amines. "

Explanation of the essence of the invention

It was therefore the object to carry out the reaction of monoethanolamine in the amination so that not only high selectivity ethylenediamine, but also by Polgereaktionen monopethanolamine and the primary reaction products, higher, preferably linear polyethylenepolyamines are formed.

This object was achieved by a process for the preparation of di- and polyethylene polyamines by amination of monoethanolamine at elevated pressure and elevated temperature of a hydrogenation catalyst in the presence of hydrogen according to the invention characterized in that in a first reaction step the monoethanolamine with excess ammonia and then in a second reaction step the primary amination product from the first reaction step after separation of the excess ammonia is converted to a secondary amination product. · .; ' "

According to the process of the invention, in the first reaction step of the amination, 30 to 60%, preferably 45 to 55% of the monoethanolamine are reacted in the presence of excess ammonia, and after the second reaction step the amount of honethanolamine is 50 to 50%, preferably 55 up to 70%, by reaction of the monoethanolamine with amines contained in the reaction mixture, ie reaction products of the first amination stage.

The ratio between ethylenediamine and monoethanolamine after the first reaction stage of the process according to the invention is 0.3 to 1.0, preferably 0.4 to 0.8 (mol), and it is obtained by the reaction of monoethanolamine with excess', ammonia an.einem hydrogenation catalyst in the presence of hydrogen in the above turnover, adjusted.

In order to obtain a sufficient selectivity of the amination of monoethanolamine by the process according to the invention in the first and second reaction stage, the reaction temperature for the second reaction stage is selected to be up to 20 K lower than for the first reaction stage, ie for example 455 K for the first and 445th K for the second reaction stage.

In the process according to the invention, between the first and second reaction stage, the ammonia content of the primary amination product is to be reduced to 0 to 5, preferably 0 to 2, Ma.-5a. To realize this measure, the primary amination product emerging from the reaction tube of the first reaction stage is decomposed in a separator at synthesis pressure into a gas and liquid phase, the liquid phase is expanded to 2 MPa and heated in a heat exchanger to 430 to 470 K, preferably 440 to 480 K. and then again decomposed into a gas and liquid phase in a separator. The liquid amination product thus obtained from the second separator is used directly in the second stage of the amination.

Instead of this simple stripping can be provided in a known manner, a pressure distillation for the removal of ammonia from the primary amination by the process according to the invention · The application of pressure when expelling the ammonia, from the primary amination product is useful to condense the ammonia with cooling water can , The ammonia from the gas phases accumulating in the two separators is condensed and returned to the first reaction stage, which depressurizes uncondensed fractions as exhaust gas. Low, with the ammonia entrained shares of water and possibly also ethylenediamine do not disturb the first Reaktionssehritt, especially since it is customary to carry out the reaction of monoethanolamine with ammonia to ethylenediamine in the presence of water *.

As amination catalysts for the first and second reaction step of the invention Yerfahrens all the reaction between monoethanolamine and ammonia or amines causing catalysts, preferably those elements containing cobalt, nickel and copper supported catalysts on alumina, can be used. ',

The possible pressure range for the process according to the invention is between 5 and 30 MPa, preferably between 12 and 20 Pa

The process according to the invention is preferably carried out continuously in the trickle phase.

The two-stage amination of the process according to the invention results in a water-clear reaction product which contains no appreciable amounts of higher-condensed substances (evaporation residue ^; 1.5 Ma % at 475 K and 130 Pa). The amination product is worked up by distillation in known manner.

embodiments

The amination reaction was carried out both for the first and the second reaction stage in a vertically arranged high-pressure reaction tube (0 28 mm, length 1500 mm). In the first reaction tube, the reactants monoethanolamine and ammonia and, if necessary, water were conveyed via Ko-bend metering pumps and the hydrogen was added via a metering orifice for quantity control. The individual product streams were combined in front of a heat exchanger used as a heater and passed out of the preheater with the desired reaction temperature in the shortest route to the reactor, where they trickled down from above over the -Katalysetorstränge (catalyst with 20 wt .-% CoO., 5 wt .-% ITiO and 4 Ma .-% CuO on Al ₂ On), after passing through the first reaction tube, the primary amination product was separated in a high pressure separator into a gas and liquid phase, the flow igp ha se relaxed to .2 MPa and then heated in a second heat exchanger (W-2) and the resulting liquid / vapor -Mixed another separator. The Gäsphasen the two separators are recycled to ^ 300 K and the liquid at 2 IvIPa ammonia'in the pump template of Ammoniakeinspritzpuinpe, the substantially consisting of hydrogen uncontrollable shares are expanded as exhaust.

Da's'in the second separator resulting liquid product was conveyed via a Kolbendosierpumpe to the head of the second reaction tube and reacted on the same amination catalyst as in the first reaction stage after passing a preheater and the addition of hydrogen in the trickle phase. The obtained after passing through the second reactor R.Areaktionsgemisch is separated in a separator in gas and Plus phase, both relaxed and forwarded the liquid phase for distillative workup and isolation of the desired amines. '

The temperature control of the amination reaction in the first and second stage was carried out by 3 in the Hochdrückreaktionsrohren centrally arranged and evenly distributed over the length of thermocouples (thermocouple sleeve 0 4 mm). Furthermore, the temperature at the outlet of the preheater was measured, whose setpoint coincided with the reaction temperature. ,

The conditions and results of the individual embodiments include the 'Table 1.'. '

Table 1

Example 1 2 ' 3 - 4 5

· 1 · reaction stage 455 458 458 ^: 458 .. 464 reaction conditions 14 20 20   , 20 ... * 20 Temperature K ¹ 0.76 0.85 '.0,85   0.85 1.12 Pressure MPa _; Load v / vh 5.3. 7.2 7.2 7.2 7.4 Einsatzproduktverh. (Mole) 0.19 0.18 0.18 0.18 ^; .- HHO / MEA 0, .15 0.12 0.12 0.12 0.25 H ₂ OAiBA Η ₂ / ΜΞΑ 53.3 48.5 48.5 48.5 60.6. Result 0 -50 0.65 0.65 0.65 0.95 ΜΞΑ sales % 4.8 3.8 2.1. 2.1 , 0.4 EDA / MEA Ratio. (Mole) 435 448 453 453 464- ! IEU-Ge ha It Ha. -% at temp. W-2K

Example ', "' 1 2 3 · 4.

2nd reaction stage. ·· '·

 Reaction conditions.

temperature κ-. MEA EDA 445 454 452 445. 453 print ¹ MPa _t BDA DETA 14 T4 .- Η 14 , 14 burden (EDA + MEA) v / vh total TETA   0.41 0.59 0.75 0.41 , 0.33 Ratio H ₂ Z (EDA-J-IiEA) (mol.) , 1st + 2nd stage DEDA .0,32 0.19 0.13 0.27 0.44 Result Selectivity Overall process ABP Sales % ' fflol-ib HBEDA 37.0 77.3 35.6  41.1 57.6 Evaporation residue "'^ 18.4 51.5 27.7 20.7. 51 ', 6 • Ma '.- 5S 32.4 72.4 33.7 37.2 · .56,1 63.4 80.8 62.3 60.4. 75.2 ). 26.0 ^: 14.4 22.8 28.1 15.9 .19,7 12.0 .19,8, , 19.4 16.4 7.9 19.2   ; 6.7 'S, 9 9.5 20.3 25.6 22.8 18.4 28.4 5.6 14.9 9.2 , 5.9 10.7 18.4 7.8 16.2 17.9 15.9. 0.88 0.83 0.71 0.54 , 0.71

s). based on reacted Elonoetb.anolamine 33) at 475 K and 130 Pa '. Abbreviations mean: ΪΊΕΑ monoethanolamine ' _: ZDk ; ethylenediamine

DETA diethylenetriamine,,. TETA triethylenetetramine

, '. DEDA piperazine, diethylenediamine AE? N-.beta.-aminoethylpiperazine HEEDA hydrozyethylethylenediamine

Claims (4)

Invention claim '...: 1. A process for the preparation of di- and polyethylene polyamines by amination of monoethanolamine at elevated pressure and elevated temperature of a hydrogenation catalyst in the presence von.Wasserstoff, characterized in that in "a first reaction step, the monoethanolamine with excess ammonia and then in a second reaction step primary amination product from the first reaction step is converted to a secondary amination product after removal of the excess ammonia 2. Method according to "point -j ^ characterized in that the first stage of the amination up to a monoethanolamine conversion of -30 to 60, preferably 45 to 55 $>» and the second stage up to a total monoethanolamine conversion of 50 to 80 %, preferably 55 to 70 % , 3. The method according to I point 1 to 2, characterized in that the second stage of the amination is carried out at up to 20 1 as the reaction temperature lower than the first 'stage. 4. The method according to item 1 to 3, characterized in that the amination product of the first stage before the reaction in the second stage of the excess ammonia to a content of - ^ 5, preferably «£ 2 Ma. -% is released.