SU1643525A1 - Method of purification of primary aliphatic amines - Google Patents

Abstract

The invention relates to α-amines, in particular, purification of primary aliphatic C, 2-C (β-amines, which are used as corrosion inhibitors. The goal is to increase the concentration of amines in distillate. For this, purification of the raw amine (obtained by nitration of paraffins followed by reduction of nitroparaffins to amines) is carried out by treating it with a mixture of stable gas gasoline or hexane with monoethanolamine at a mass ratio of 1: (0.66-1) :( 0.3-0.5). In this case, the amines are extracted with carbon hydrogen, and impurities - polar dissolve (monoethanolamine). The extracts are then distilled to give the desired amines as a distillate. In the latter, the amine content is 93.8-97.4% versus 48.6%. These conditions exclude the use of expensive reagents, allow reduce water consumption and ensure recycling of solvents. 1 ill., 4 tab. С / С

Description

The invention relates to chemical technology, in particular to a method for purifying higher aliphatic amines which can be used as inhibitors of acid corrosion of equipment.

The aim of the invention is to increase the concentration of the amine fraction in the purified product.

The drawing shows the installation that implements the proposed method.

The extraction column 1 is equipped with a nozzle made of glass rings (equivalent to five theoretical plates). Separators 2 and 3 of the phases are designed to separate and return solvents into the monoethanolamine cycle in separator 2 and the hydrocarbon in the separator 3. In the distiller 4, the pro- (the distillation of the hydrocarbon solution is wired, which is condensed in the refrigerator 5 and returned to extractor 1. The bottom product from the separator 3 is treated with water, the aqueous layer is separated from the organic layer containing resinous impurities. The latter is removed from the system from the sump 6. The resulting aqueous layer of NEPЈo, and

N

SG

water is distilled from monoethanolamine. Water vapor from the top of the distiller 7 is cooled in the refrigerator 8 and the condensate is returned to the water treatment stage of the stream from the separator 3 containing monoethanolamine and gums. The bottoms from the distiller 7, which is the monoethanolamine fraction, are cooled in the refrigerator 9 and sent to the distiller 1 for reuse in the cleaning process.

The starting material is the reaction mixture of primary aliphatic amines Cjj-C obtained from paraffins through the nitration stage, followed by reduction of nitroparaffins to amines. The content of amines in raw materials

41-54 wt.%. As a dissolvent, the results are listed in Table. 2,

YU

J5

Leu use stable gasoline, hexane and monoethanolamine qualification pure.

Example 1. Amine raw containing primary aliphatic amines 25 in the amount of 44.2 wt.%, Served in the middle of the Packed column 1. In the upper part of the column enters monoethanolamine, in the lower hydrocarbon solvent. The temperature of the initial components of the room. Warming up takes place in column 1 and the temperature rises by 5-7 ° C.

From the top of the column 1 take a solution of amines in hydrocarbons. After settling in the phase separator 2 and separating the entrained monoethanolamine, the amine solution enters the distiller 4, where the hydrocarbon solvent is distilled off at a vapor phase temperature of 69 ° C, which is condensed in the refrigerator 5 and returned to the columns 1. The amines are isolated as a marketable product . .

The resin solution in monoethanolamine from the bottom of the column is divided into two layers in a 3 phase separator. Carried away hydrocarbons return to the column, and the solution of the resin in monoethanolamine is mixed with water in a mass ratio of 1: 4. In settler 6, the mixture is divided into two layers. The upper layer (resin) is removed from the system, and the lower one (aqueous solution of monoethanolamine) is sent to the distiller 7, where water vapor is distilled off at a temperature lower than the distiller, not higher than 115 ° C. prayer, monoethanolamine. Water vapor

40

45

50

55

Stable gasoline (measure 8) has the following composition, Isopentane,

Normal pentane 34, a mixture of hexanes and higher hydrocarbons, 64 Gasoline is characterized by the following indicators:

Boiling point, 0:

top38,

end of 138

Residue + loss,% 2, Density, kg / dm 0,

(20

For comparison, the process of purification of the starting fraction with C yes. Is carried out. -C ° n ° to the known ratio of crude amine: hexane: 1: 1: 2. The amine content increased from 44.2 to 48.6 wt.% In course of production. Since the increase in the amine content is small, the known value in this case is not practical.

The content of amines in the course of the product after purification (the mass of crude amine is 1) is given in Table. 3

As follows from the table. 3 data proposed from the purification of raw amine from impurities to obtain the final product by holding the main substance 9 33.8 wt.%, Which is significantly you by a known method (48.6 mA

The economic efficiency of the method is confirmed

(Condensed in a water cooler 8 and returned to the process. Monoethanolamine after cooling in the refrigerator 9 is recycled.

Mass, process flow, their composition and the results obtained are given in Table. one.

The degree of extraction of aciii is 92.8%, the content of the target fraction of amines in the purified product is 96.6 wt.%.

Examples 2-8. The crude amine purification process is carried out under the conditions of example 1, varying the ratio of solvents, the concentration of the target fraction in the feedstock (example 7) or using stable gas gasoline as the hydrocarbon (example 8).

Mode parameters and received re

five

0

five

0

five

Stable gasoline (example 8) has the following composition, wt.%: Isopentane, 0.33

Normal pentane 34.79 A mixture of hexanes and higher hydrocarbons64, 88 Gasoline is characterized by the following indicators:

Boiling point, 0:

top38,8

end of 138.2

Residue + loss,% 2.9 Density, kg / dm 0.704

()

For comparison, the method of purification of the initial fraction of amines C da.-C ° n ° C is carried out to a known method with a crude amine: hexane: water ratio of 1: 1: 2. The amine content is increased from 44.2 to 48.6% by weight in the final product. Since the increase in the concentration of amines is small, the known method is of no practical importance in this case.

The content of amines in the final product after purification (the mass fraction of the crude amine is 1) is given in table. 3

As follows from the table. 3 data, the proposed method of purification of raw amine from impurities allows to obtain the final product with the content of the main substance of 97.4 - 33.8 wt,%, which is significantly higher than by a known method (48.6 wt.%).

The economic efficiency of the proposed method is confirmed by its

by comparison with the famous, in which 16

The amine release method is treated with sulfuric acid followed by neutralization of the resulting amine salt with alkali.

The main technical and economic indicators of the purification stage of amines according to the known and proposed methods are given in table. four.

Claims (1)

When implementing the proposed method in practice, the annual economic effect per unit of commercial product will be at least 295 rubles per ton due to the elimination of expensive reagents, reduction of water consumption and the possibility of recycling solvents in the proposed method. Invention Formula The method of purification of primary aliphatic amines by treating five -0.5). raw material obtained by nitrating paraffins, followed by reducing the resulting nitroparaffins to amines with a mixture of liquid paraffin carbon-4 hydrogen and a polar solvent with simultaneous extraction of amines with a hydrocarbon, and impurities with a polar solvent, and separating the extracts in a distillation column. to produce amines in the form of distillates This is characterized in that, in order to increase the concentration of amines in the distillate, stable gas gasoline or hexane is used as hydrocarbons, and as polar gas monoethanolamine is used in the vortel with a mass ratio of amine-raw hydrocarbon gmonoethanolamine 1: (0.66-1) :( 0.3 Note. Hexane was used as a hydrocarbon (examples 1-7), and stable gas gasoline (example 8). Table .Table 2 Production capacity of amines, C, t / year 3000 Sulfuric acid consumption, t / year3600 Cost of sulfuric acid, thousand rubles year 360 Alkali consumption, t / year T 224 The cost of alkali, thousand rubles. year 612 Water consumption, thou.m year 1800 Steam consumption, tons / year Cost of steam, thousand rubles The cost of water, thousand rubles. year 18 Monoethanolamine, t / year The cost of monoethanol amine, thousand "rub. year Stable gas gasoline (Su + v), tons / year Cost of stable gas gasoline, thousand rubles year Capital investment - RUB thousand 50 The economic effect on the volume of production, thousand rubles. year The economic effect per unit of production. . rub./t Table 3 3000 3241.5 600 15.6 32.4 100 36,100 5,150 886 295.3 Crude amine