DE1768853A1 - Process for the continuous production of mono- and / or di- and / or triaethylamine - Google Patents

Description

Process for the continuous production of mono- and or or The and or or triethylamine The invention relates to a process for continuous Production of mono- and / or die and / or triethylamine by hydrogenation of acetonitrile over a fixed catalyst. In the manufacture of acrylonitrile the ammoxidation of propylene produces large amounts of acetonitrile as a by-product received, which must be supplied to an economic recovery. One of the ways this consists in converting this acetonitrile into ethylamines by hydrogenation, It is known to produce acetonitrile by catalytic hydrogenation with hydrogen in the presence of metals or oxides, such as nickel, with the simultaneous addition of ammonia to be converted into the primary amine.

According to another known method, a special catalyst is used based on nickel, which is evenly mixed with alkali metal salts, through reduction primary amine generated from acetonitrile with hydrogen.

Furthermore, a method for producing, in particular, sec. and or or tert. Amines known after the acetonitrile with acetaldehyde at increased Temperature reacted with hydrogen over nickel catalysts to die and riethylamine will.

The disadvantage of the known method is that after each only monoethylamine or di- or triethylamine can be obtained. A Another disadvantage is the additional consumption of ammonia and acetaldehyde.

The invention is based on the object of creating a method with which it is possible to mix mixtures of mono-, The and triethylamine to get in which the three amines in a desired proportion are present, so that it is possible, then only one of the three amines in high Gain concentration.

This object is achieved by a process for continuous production of mono- and or or die and or or triethylamine by hydrogenation of acetonitrile on a fixed catalyst, with the hydrogen and the products in be circulated in a manner known per se, solved according to the invention by that the hydrogenation is carried out at pressures of 5 to 230 atm and the product separation is carried out in a temperature range from - 33 ° to + 50 0C.

Namely, it has surprisingly been found that, as shown in the following Table shows a relationship between the quantitative composition des Äthylamineemis Ches and the temperature at which the mixture of the cycle gas is deposited, exists.

The following table shows the dependency of the quantitative composition of the product formed from the product separator temperature at a pressure of for example 40 at.

Table 1 Product formed by separators in% by weight based on temperature the total amines ° C mono- di-triamine - 30 90.0 6.1 3.9 - 20 64.0 31.6 4.4 - 10 35.0 61.4 3.6 0 3.6 9023 6.1 + 10 4.0 65.8 31.2 + 20 2.5 24.8 72.7 + 30 2.0 6.2 91.8 The known arrangements for hydrogenation are suitable for carrying out the process under increased pressure and temperature. It can e.g. B. a hydrogenation reactor with several reaction tubes, which are flushed with a coolant, for use come. There are no special design requirements for the product separator posed; he only needs a sufficient calming of the cycle gas and a ensure that the temperature is kept constant. By the invention Separator temperatures will determine the composition of the cycle gas and thus its Density significantly influenced.

The reaction product is removed from the separator in liquid form and fed to the distillation.

All conventional catalysts are used as catalysts for carrying out the procedure Nitrile hydrogenation catalysts suitable, e.g. B. Nickel on silica gel, or chromium oxide Alumina, cobalt on silica gel cder alumina and eesir. tertiary cobalt.

The used sydation temperatures depend on the used Catalysts and are generally between 100 and 200 00, preferably between 140 and 180 00.

The working pressure also depends on the activity of the catalysts away; it can be varied within wide limits.

To produce only one of the amines in high concentration, it is advantageous to carry out the hydrogenation in a pressure range from 35 to 45 atm. It is preferred to work at a hydrogen pressure of 40 atm (see Table 1).

The following tables show the pressure dependency of the product composition at a constant separator temperature.

Table 2 Pressure dependence of the product composition at constant Separator temperature of + 30 ° C working pressure Product formed in% by weight, based on at on the total amines mono- di-triamine 5 71.3 24.3 4.4 10 44.8 40.3 14.9 20 21.6 27.4 51.0 40 3.1 9.2 87.7 100 22.9 40.0 37.1 230 17.4 48.8 33.8 Tabel 3 The pressure dependency of the product composition at constant separator temperature Product formed by a working pressure of - 23 ° C in weight-based at the total amines Mono- diamine 5 63.8 32.4 3.8 10 57.0 33.9 9.1 20 58.3 35.1 6.5 40 69.0 24.4 6.6 100 34.4 45.6 20.0 230 26.3 43.8 29.0 Using the information given in the tables and the following examples are the most favorable temperature and pressure conditions in each case easy to determine empirically.

Example 1 The experimental set-up consisted of a high pressure hydrogenation reactor with the dosing devices for the products, a gas compressor for the hydrogen and product circuit, preheaters, coolers and a jacketed product separator. 2 liters of a nickel catalyst were firmly arranged in the hydrogenation reactor. The catalyst was obtained by joint precipitation of a nickel and chromium nitrate (molar ratio 5: 1) made using soda solution. The precipitated product was calcined at 420 oC and, compressed into pills, used for hydrogenation. The activation temperature of the catalyst was 180,000. The system pressure was 40 atm. hydrogen. It became 600 ml / h of acetonitrile are metered in. The acetonitrile was evaporated using hydrogen and hydrogenated at 150 ° C.

At a separator temperature of -29 ° C, the used Acetonitrile formed an amine mixture with the following amine proportions (based on weight the total amines): monoethylamine 88.0% diethylamine 10.2; Triethylamine 1.8% Die The yield and the conversion were quantitative.

Example 2 The experimental set-up was the same as in Example 1.

Only the separator temperature was set to -2 0C and the system pressure changed to 36 atm hydrogen.

An amine mixture with the following amine proportions was made from the acetonitrile formed (by weight, based on the total amines): monoethylamine 4, 1% diethylamine 91.0% triethylamine 4.9% The yield and the conversion were quantitative.

Example 3 The experimental set-up was the same as in Example 1.

Only the separator temperature was set to 34 oC and the system pressure changed to 42 atm of hydrogen.

The acetonitrile became an amine mixture with the following amine proportions formed (% by weight, based on the total amines): monoethylamine 2.3% diethylamine 8.4% triethylamine 89.3% The yield and the conversion were quantitative.

Example 4 The experimental set-up was the same as in Example 1.

It was only the separator temperature to 30 0C and the system pressure changed to 5 atm hydrogen.

The acetonitrile became an amine mixture with the following amine proportions formed (by weight, based on the total amines): monoethylamine 68.2 s diethylamine 27.5% triethylamine 4.3% The yield and the conversion were quantitative.

Example 5 The experimental set-up was the same as in Example 1.

Only the separator temperature was set to - 23 0C and the system pressure changed to 230 atm hydrogen.

The acetonitrile became an amine mixture with the following amine proportions formed (% by weight, based on the total amines): monoethylamine 28.2% diethylamine 41.8% triethylamine 30.0 s The yield and the conversion were quantitative.

Claims (2)

Claims 1. Process for the continuous production of Mono- and or or Die and or or triethylamine by hydrogenation of acetonitrile on a foot-mounted catalyst, the hydrogen and the products in the Circulation are performed, characterized in that the hydrogenation at pressures carried out from 5 to 230 at and the product deposition in a temperature range from - 33 0 to + 50 0C. 2. The method according to claim 1, characterized in that in the Production of only one of the amines in high concentration the hydrogenation in a pressure range from 35 to 45 at, preferably at 40 at.