RU2284314C1 - 2-ethylhexanol production process - Google Patents

Abstract

FIELD: industrial organic synthesis.

SUBSTANCE: process involves aldol condensation of n-butyric aldehyde in presence of 1-3% aqueous NaOH solution to form 2-ethyl-2-hexenal, which is washed out to remove alkali residues and distilled on steam stripping rectification column to separate high-boiling products, after which it is hydrogenised on copper-chromium catalyst to produce 2-ethylhexanol. 2-Ethyl-2-hexenal distillation bottom residue is treated for 15-60 min with aqueous NaOH solution at 100-120°C and aqueous NaOH solution-to-bottom residue volume ratio 1:(4-10). Alakali effluent produced in n-butyric aldehyde aldol condensation stage is evaporated to NaOH concentration 15-30% and then utilized to treat 2-ethyl-2-hexenal distillation bottom residue, while water steam obtained from evaporation is used as vaporizing agent in stripping rectification column.

EFFECT: reduced (by a factor of 20-50) volume of alkali effluent in aldol condensation stage.

2 tbl, 10 ex

Description

The invention relates to the field of petrochemical synthesis and may find application in the preparation of 2-ethylhexanol by aldol condensation of n-butyraldehyde.

BACKGROUND

A known method of producing 2-ethylhexanol, according to which formed in the process of aldol condensation of n-oil aldehyde in the presence of 1-3 wt.% Aqueous solution of NaOH 2-ethyl-2-hexenal is washed with water from alkali residues, separated from high-boiling products by steam distillation in a stripping distillation column, and then hydrogenated on a copper-chromium catalyst in 2-ethylhexanol (Rybakov V.A., Elkin A.L. et al. Technology of oxosynthesis and related processes involving carbon monoxide: - Alex-Press LLC, Perm, 2004 .-- p. 170-176 (ISBN 5-88345-082 -2).

However, this method is characterized by several disadvantages, namely:

- increased yield of by-products of high boiling point at the aldol condensation stage of n-butyric aldehyde (up to 2.5%);

- reduced installation performance;

- increased amounts of alkaline wastewater due to the release of water by the condensation reaction of n-butyraldehyde in 2-ethyl-2-hexenal and the subsequent washing of the reaction products with water from alkali residues.

The closest to the proposed invention in technical essence and the achieved result is a method for producing 2-ethylhexanol by aldol condensation of n-butyraldehyde in the presence of a catalyst - an aqueous solution of NaOH with the formation of 2-ethyl-2-hexenal, which after distillation is hydrogenated on a copper-chromium catalyst in 2-ethylhexanol, including the additional stage of processing the bottom residue of rectification of 2-ethyl-2-hexenal with 15-20 wt.% aqueous NaOH at a temperature of 100-120 ° C, for 15-60 minutes, with a volume ratio ii NaOH aqueous solution: bottoms ratio of 1: 4-10 (Pat RU 2155180. Kirillov OY, Chekryshkin YS et al..).

However, this method is characterized by increased consumption of alkali and alkaline wastewater.

SUMMARY OF THE INVENTION

The invention is aimed at solving the problem - improving the technical and economic indicators of the process (reducing the amount of waste - alkaline wastewater).

The solution to this problem is mediated by a new technical result. This technical result consists in the additional effect of the aldol condensation stage of n-butyraldehyde on alkaline wastewater by evaporation.

SIGNIFICANT SIGNS

Obtaining 2-ethylhexanol by aldol condensation of n-butyric aldehyde in the presence of a catalyst of a -1-3 wt.% Aqueous solution of NaOH with the formation of 2-ethyl-2-hexenal, which after washing with water from alkali residues and distillation using high-temperature by-product steam the products in a stripping distillation column are hydrogenated on 2-ethylhexanol on a copper-chromium catalyst, while the bottom residue of the distillation of 2-ethyl-2-hexenal is treated with an aqueous solution of NaOH at a temperature of 100-120 ° C for 15-60 minutes at a volumetric water ratio th solution of NaOH: VAT residue equal to 1: 4-10.

FEATURES

The method DISTINCTIVE according to claim 1, wherein the alkaline wastewater of the aldol condensation stage of n-butyraldehyde is evaporated to obtain a concentration of NaOH of 15-30 wt.% And then used to treat the distillation residue of 2-ethyl-2-hexenal, and the resulting upon evaporation, water vapor is used as an evaporating agent in a stripping column of rectification of 2-ethyl-2-hexenal.

According to the proposed method, the production of 2-ethylhexanol is carried out through the stage of aldol condensation of n-butyric aldehyde in the presence of 1-3 wt.% Aqueous NaOH solution to obtain 2-ethyl-2-hexenal, which, after washing from alkali residues, is distilled off from high-boiling by-products in stripping distillation column. Purified by steam distillation, 2-ethyl-2-hexenal is then hydrogenated on a copper-chromium catalyst in 2-ethylhexanol. The high-boiling products remaining during the distillation of 2-ethyl-2-hexenal (bottoms) are treated with a 15-30 wt.% Aqueous NaOH solution obtained by evaporation of alkaline wastewater from the aldol condensation stage at a temperature of 100-120 ° C for 15-60 minutes, with a volume ratio of NaOH solution: VAT residue equal to 1: 4-10. The water vapor obtained by evaporation of alkaline wastewater is sent to a stripping column of rectification of 2-ethyl-2-hexenal as an evaporating agent. The 2-ethyl-2-hexenal formed during treatment with an aqueous NaOH solution is isolated by distillation and sent to the hydrogenation step in 2-ethylhexanol.

The essence of the proposed method for producing 2-ethylhexanol is illustrated by examples.

Example 1

A 1000 ml two-necked flask equipped with a thermometer and a water cooler is charged with 600 ml of alkaline wastewater generated during the aldol condensation step of n-butyraldehyde. Evaporation of wastewater is carried out on an electric stove to obtain a concentration of an aqueous solution of NaOH in a flask of 10 wt.%. The alkali content in the initial and stripped off solutions is determined by titration. Thus obtained 10 wt.% Aqueous NaOH solution is used to treat the distillation residue of 2-ethyl-2-hexenal.

Example 2

In the conditions of example 1, the evaporation of wastewater is carried out to obtain a concentration of an aqueous solution of NaOH in a flask of 15 wt.%.

Example 3

In the conditions of example 1, the evaporation of wastewater is carried out to obtain a concentration of an aqueous solution of NaOH in a flask of 20 wt.%.

Example 4

In the conditions of example 1, evaporation of wastewater is carried out to obtain a concentration of an aqueous solution of NaOH in a flask of 25 wt.%.

Example 5

In the conditions of example 1, the evaporation of wastewater is carried out to obtain a concentration of an aqueous solution of NaOH in a flask of 30 wt.%.

The results of evaporation of alkaline wastewater (examples 1-5) are given in table 1.

As can be seen from the results, the evaporation of alkaline wastewater stage aldol condensation allows you to expand, compared with the prototype, the upper concentration limit used for the treatment of bottoms of distillation of 2-ethyl-2-hexenal aqueous solution of NaOH to 30 wt.%, As this is not only It will not increase the total consumption of alkali, but it will further reduce the total amount of wastewater.

The boiling point of the solution above 100 ° C during evaporation of alkaline wastewater allows not to condense evaporating water vapor, but to use it as an evaporating agent in a stripping column of rectification of 2-ethyl-2-hexenal.

Table 1
The results of the evaporation of alkaline wastewater stage aldol condensation of n-butyric aldehyde Example No. The initial concentration of NaOH in wastewater, wt.% The initial volume of wastewater, ml Temperature ° C The resulting concentration of NaOH, wt.% The resulting volume of aqueous solution, NaOH, ml Decrease in alkaline wastewater, times one 0.75 600 103 10 40 fifteen 2 0.75 600 105 fifteen 26 23 3 0.75 600 109 twenty eighteen 33 four 0.75 600 112 25 fourteen 43 5 0.75 600 119 thirty eleven 54

Example 6

In a 500 ml three-necked flask equipped with a mechanical stirrer with a water trap and reflux condenser, 200 ml of the cubic residue of the distillation of 2-ethyl-2-hexenal obtained during the aldol condensation of n-butyraldehyde and 10 ml of a 10 wt.% Aqueous solution of NaOH are placed obtained by evaporation of wastewater (volume ratio 1:20). The temperature of the reaction mixture was maintained equal to 90 ° C. After mixing the components at certain time intervals, 10 ml of the mixture are selected, washed with water and analyzed on a gas-liquid chromatograph. Quantitative analysis is carried out by the internal standard method (n-amyl alcohol).

The results of the processing of the bottom residue of the rectification of 2-ethyl-2-hexenal with an aqueous solution of NaOH (examples 6-10) are shown in table 2.

Example 7

Under the conditions of Example 6, 300 ml of a bottoms distillation residue of 2-ethyl-2-hexenal and 25 ml of 15, 20 and 25% by weight of an aqueous NaOH solution obtained under the conditions of Example 1 were added into a three-necked flask (volume ratio 1:12). The temperature of the reaction mixture is maintained at 90, 100, 110, 120 and 130 ° C. Mixing of the components is carried out for 15, 30, 45, 60 and 75 minutes.

Example 8

Under the conditions of Example 6, 250 ml of a bottoms distillation residue of 2-ethyl-2-hexenal and 25 ml of 10, 15, 20, 25, and 30 wt% of an aqueous NaOH solution obtained under the conditions of Example 1 were added into a three-necked flask (volume ratio 1:10) . The temperature of the reaction mixture is maintained at 90, 100, 110, 120 and 130 ° C. Mixing of the components is carried out for 15, 30, 45, 60 and 75 minutes.

Example 9

Under the conditions of Example 6, a 200 ml distillation residue of 2-ethyl-2-hexenal and 50 ml of 10, 15, 20, 25, and 30 wt.% Aqueous NaOH solution obtained under the conditions of Example 1 were added into a three-necked flask (volume ratio 1: 4) . The temperature of the reaction mixture is maintained at 90, 100, 110, 120 and 130 ° C. Mixing of the components is carried out for 15, 30, 45, 60 and 75 minutes.

Example 10

Under the conditions of Example 6, 150 ml of a bottoms distillation residue of 2-ethyl-2-hexenal and 50 ml of 10, 15, 20, 25 and 30 wt.% Aqueous solution of NaOH obtained under the conditions of Example 1 were added into a three-necked flask (volume ratio 1: 3) . The temperature of the reaction mixture is maintained at 90, 100, 110, 120 and 130 ° C. Mixing of the components is carried out for 15, 30, 45, 60 and 75 minutes.

Thus, the use of the proposed method for the production of 2-ethylhexanol, including the additional stage of evaporation of alkaline wastewater stage aldol condensation of n-butyric aldehyde to obtain a concentration of NaOH 15-30 wt.% And use them to treat the bottom residue of distillation of 2-ethyl-2-hexenal moreover, the water vapor obtained by evaporation is used as an evaporating agent in a stripping column for rectification of 2-ethyl-2-hexenal, which reduces the amount of alkaline wastewater at the aldol condensation stage by 20-50 times.

table 2
The results of the processing of the bottoms of the distillation of 2-ethyl-2-hexenal with an aqueous solution of NaOH * N example Temperature ° C Volumetric ratio. aqueous solution of NaOH: VAT residue The content of 2-ethyl-2-hexenal in the bottom residue (in wt.%) After processing for min 10 fifteen thirty 45 60 75 one 2 3 four 5 6 7 8 9 10 wt.% Aqueous NaOH solution 6 90 1:20 0.8 1.2 1.4 1.4 1.7 1.8 15 wt.% Aqueous NaOH solution 7 90 1:12 1.2 2.3 3.5 4.0 4.5 5.3 7 one hundred 1:12 7.4 8.5 9.8 11.3 13.1 16.3 7 110 1:12 8.2 10.4 12.7 14.4 17.6 19.1 7 120 1:12 9.3 13.2 14.3 17.2 19.6 20.7 7 130 1:12 8.3 2.4 15.1 15.2 14.0 15.3 20 wt.% Aqueous NaOH solution 7 90 1:12 3.2 4.6 5.7 6.7 9.1 10.4 7 one hundred 1:12 6.9 8.7 10.9 13.8 15.8 17.9 7 110 1:12 9.4 10.5 12.7 15.4 18.5 20.2 7 120 1:12 8.9 3.8 15.0 19.2 16.1 14.6 7 130 1:12 9.6 13.0 14.8 16.6 14.4 14.4 25 wt.% Aqueous NaOH solution 7 90 1:12 5.4 7.1 10.5 15.5 20.2 22.4 7 one hundred 1:12 8.0 9.4 12.3 13.8 16.2 18.5 7 110 1:12 9.4 10.2 15.4 18.8 20.2 21.1 7 120 1:12 8.4 12.3 17.3 22.2 22.4 21.0 7 130 1:12 10.7 13.5 18.4 22.4 21.9 20.8 Continuation of Table 2 one 2 3 four 5 6 7 8 9 10 wt.% Aqueous NaOH solution 8 90 1:10 0.9 1.2 1.5 1.7 1.7 1.8 8 one hundred 1:10 2.2 10.1 12.3 15.5. 17.2 18.0 8 110 1:10 2.4 12.8 16.8 20.1 24.5 25.1 8 120 1:10 6.5 17.7 19.1 23.2 27.4 27.7 8 130 1:10 6.0 16.8 23.4 25.2 25.2 24.3 15 wt.% Aqueous NaOH solution 8 90 1:10 4.4 6.1 6.3 6.3 6.5 6.3 8 one hundred 1:10 6.8 21.2 23.8 25.4 28.4 28.7 8 110 1:10 10.0 29.2 32.4 36.0 39.9 41.1 8 120 1:10 13.3 37.6 39.9 42.2 44.0 44.7 8 130 1:10 16.2 40.6 41.1 42.5 40.9 39.3 20 wt.% Aqueous NaOH solution 8 90 1:10 6.1 10.4 10.2 11.7 13.0 13.4 8 one hundred 1:10 9.1 25.8 28.8 34.9 40.1 40.9 8 110 1:10 12.7 38.1 40.7 41.7 42.0 42.1 8 120 1:10 17.3 42.1 43.8 44.0 45.4 44.9 8 130 1:10 20.6 40.0 44.6 45.3 43.4 40.5 25 wt.% Aqueous NaOH solution 8 90 1:10 16.3 20.2 23.4 25.0 26.1 26.5 8 one hundred 1:10 23.6 26.0 30.2 30.5 32.2 33.0 8 110 1:10 29.5 39.2 41.1 42.1 43.6 42.8 8 120 1:10 32.4 42.1 44.3 44.2 44.7 43.0 8 130 1:10 40.7 43.4 41.7 42.5 41.4 40.5 30 wt.% Aqueous NaOH solution 8 90 1:10 16.8 21.0 25.2 28.2 28.5 28.2 8 one hundred 1:10 24.3 27.2 32.4 33.7 31.2 31.6 8 110 1:10 29.1 38.7 39.9 41.7 42.4 40.6 8 120 1:10 34.1 44.9 45.7 42.3 41.8 40.3 8 130 1:10 40.8 42.9 40.6 40.6 39.4 39.0 Continuation of Table 2 one 2 3 four 5 6 7 8 9 10 wt.% Aqueous NaOH solution 9 90 1: 4 10.2 11.6 12.5. 15.1 17.9 21.1 9 one hundred 1: 4 12.2 14.4 16.7 18.7 21.5 22.8 9 110 1: 4 14.1 1.82 18.7 22.2 26.9 28,2 9 120 1: 4 16.2 19.5 24.4 27.3 30.1 32.7 9 130 1: 4 18.0 27.1 29.1 34.5 34.4 30.6 15 wt.% Aqueous NaOH solution 9 90 1: 4 12.7 18.5 22.1 26.2 28.7 30.2 9 one hundred 1: 4 16.2 41.4 44.6 47.7 49.1 49.5 9 110 1: 4 16.1 42.1 45.4 46.9 48.8 49.3 9 120 1: 4 19.6 42.7 47.2 48.0 49.9 50.0 9 130 1: 4 21.4 45.6 50.5 48.2 47.9 46.3 20 wt.% Aqueous NaOH solution 9 90 1: 4 15.1 25.6 27.6 29.4 30.5 32.4 9 one hundred 1: 4 19.2 48.8 51.3 53.0 53.3 52.8 9 110 1: 4 20.5 49.3 52.7 53.6 54.0 53.5 9 120 1: 4 24.7 49.6 53.3 54.0 53.8 53.0 9 130 1: 4 25.2 53.6 52.0 51.1 49.7 48.7 25 wt.% Aqueous NaOH solution 9 90 1: 4 12.2 22.7 27.6 31.0 33.2 33.6 9 one hundred 1: 4 17.5 47.2 50.8 51.0 49.7 47.2 9 110 1: 4 19.2 50.0 50.7 48.7 46.9 45.1 9 120 1: 4 24.5 49.7 48.7 47.2 45.9 43.4 9 130 1: 4 25.9 49.9 48.6 46.3 45.9 42.5 30 wt.% Aqueous NaOH solution 9 90 1: 4 14.8 25.9 30.2 33.0 35.2 35.6 9 one hundred 1: 4 27.0 44.2 52.0 52.0 48.4 48.4 9 110 1: 4 28.2 48.9 50.9 48.7 45.2 45.2 9 120 1: 4 28.2 49.9 47.6 45.1 44.0 40.1 9 130 1: 4 30.9 51.0 46.2 44.8 43.9 40.1 Continuation of Table 2 one 2 3 four 5 6 7 8 9 10 wt.% Aqueous NaOH solution 10 90 1: 3 10.7 18.9 24.4 27.7 30.1 32.2 10 one hundred 1: 3 25.2 29.4 32.5 37.3 39.0 39.6 10 110 1: 3 26.2 32.7 35.9 39.4 40.3 42.0 10 120 1: 3 27.0 33.9 38.0 41.1 44.1 41.1 10 130 1: 3 27.9 37.0 40.1 43.6 46.1 46.1 15 wt.% Aqueous NaOH solution 10 90 1: 3 12.4 19.6 24.2 28.4 29.4 30.0 10 one hundred 1: 3 26.2 40.2 44.6 47.7 49.1 49.5 10 110 1: 3 26.1 42.6 45.0 47.7 47.3 48.6 10 120 1: 3 28.6 42.9 46.4 50.9 49.6 49.3. 10 130 1: 3 29.4 44.3 48.3 50.5 46.4 40.3 20 wt.% Aqueous NaOH solution 10 90 1: 3 12.7 20.1 23.5 25.3 27.4 30.4 10 one hundred 1: 3 25.2 42.3 48.2 49.1 52.8 52.9 10 110 1: 3 25.5 43.3 50.6 53.3 53.8 52.4 10 120 1: 3 27.8 44.8 50.0 52.5 51.9 50.4 10 130 1: 3 28.4 43.6 46.0 45.4 42.6 40.7 25 wt.% Aqueous NaOH solution 10 90 1: 3 13.0 21.7 24.3 28.4 30.1 31.6 10 one hundred 1: 3 27.4 45.9 48.2 47.0 46.4 46.2 10 110 1: 3 26.2 48.2 47.1 46.8 46.9 44.1 10 120 1: 3 23.5 45.8 44.7 42.2 40.7 41.1 10 130 1: 3 24.9 43.1 43.0 41.8 39.5 37.6 30 wt.% Aqueous NaOH solution 10 90 1: 3 13.1 24.4 28.9 31.0 33.6 33.8 10 one hundred 1: 3 29.0 46.2 47.7 47.7 45.5 44.2 10 110 1: 3 33.9 45.9 46.2 46.2 43.8 40.0 10 120 1: 3 36.6 45.9 42.8 41.9 39.8 38.2 10 130 1: 3 39.7 44.0 40.8 39.6 37.2 36.0 * The initial content of 2-ethyl-2-hexenal in the bottom residue of 0.49 wt.%

Claims (1)

The method of producing 2-ethylhexanol by aldol condensation of n-butyric aldehyde in the presence of 1-3 wt.% Aqueous NaOH solution with the formation of 2-ethyl-2-hexenal, which, after washing from alkali residues, is distilled with steam in a stripping distillation column from high boiling products and then hydrogenated on a copper-chromium catalyst in 2-ethylhexanol, while the bottom residue of the distillation of 2-ethyl-2-hexenal is treated with an aqueous solution of NaOH at 100-120 ° C for 15-60 minutes, with a volume ratio of an aqueous solution of NaOH: VAT residue equal to 1 : 4-10, characterized in that the alkaline wastewater obtained in the aldol condensation step of n-butyric aldehyde is evaporated to a NaOH concentration of 15-30 wt.% And then used to treat the distillation residue of 2-ethyl-2-hexenal, and water vapor obtained by evaporation is used as an evaporating agent in a stripping column for rectification of 2-ethyl-2-hexenal.