SU1395623A1 - Method of separating 2-ethylhexanol from mixture containing butyl alcohols - Google Patents

Abstract

The invention relates to aliphatic alcohols, in particular, the method of separating 2-ethyl 1 hexanol (EG) from a mixture containing butyl alcohols, which can be used to obtain a plasticizer. In order to utilize production and increase the degree of extraction of EG and butanol from bottom products containing ethers, rectification is carried out. the latter at 150,200 mm Hg and 50-55 ° C at the top of the first Distillate column (light-boiling components) are removed from the system, and the bottoms (EG, esters, high-boiling components) are separated in the second column at 105-II5 C at the top of the column and 20 -80 mm Hg, the bottom product (high boiling components) is removed from the system, and the distillate (EG-raw) is separated in the third column at 60-70 ° C at the top of the column and 75-100 mm pTOSTO in the presence of an aqueous alkali solution ( 40%), Distillate (azeatropic mixture of butanol and water: which is separated by exfoliation) is removed from the system, and the bottoms (EG, high the oxidizing components, minus} are divided in the fourth column at 113-115 ° C at the top of the column and 82–90 mm pTOSTO per cubic product — high-boiling components, soaps, and distillate — the target EG. esters and the release of the resulting butanol to increase the purity and yield of the EG to 89.9- 91% against 74.8-82.6% in the known method, while it does not contain acidic impurities, 2 tablé (O (L 00 01 05

Description

The invention relates to aliphatic alcohols, in particular, to an improved method for separating 2-ethylhexanol from a mixture containing butyl alcohols, namely from bottom products of the production of boot-based alcohols according to the naphthenate-evaporation scheme.

This mixture, which also contains ethers, is obtained as a VAT residue at the stage of rectification of hydrogenation of zate with the isolation of n-butyl and iso-butyl alcohols. Dedicated 2-ethylhexanol can be used to obtain a plasticizer.

The bottoms of the production of butyl alcohols have the composition, wt% 2 light-boiling components 29, 2-ethylhexanol 50, esters 6, high-boiling components 15 sec.

Its qualitative indicators are the following: acid number 1.5 mg KOH / g, saponification number 31.0 mg KOH / g, carbonyl 2.6 mg KOH / G, iodine 2.0 g Ij / lOO g.

The light-boiling components are represented by an in-separable mixture of butyl alcohols (n-butanol, iso-butanol) and neutral impurities in a ratio of 1; 2 s,

High-boiling components are products of compaction (resin-forming) in a mixture with high-molecular alcohol.

The esters are represented by a mixture of butyl fatty acid esters, boiling away in the temperature range of 165–200 ° C at atmospheric pressure.

The purpose of the invention is the utilization of waste production of butyl alcohols by the method of oxosynthesis and an increase in the degree of extraction of 2-ethhexanol and butanol from the bottom products of this production, containing ethers, achieved by the rectification of the latter at a temperature at the top of the first column at 50-55 ° C and a residual pressure of 150-200 mm Hg, distillate - boiling components, which are removed from the system, and the bottom product of composition - 2-ethylhexanol, ethers, high-boiling components, which are separated in the second column at a temperature at the top of 105-115 ° C and a residual pressure of 20-80 mm pToSt per cubic product - high-boiling components withdrawn from the system, and a 2-ethexanol hexanol distillate of the composition 2-1x1hexanol, ethers, high boiling components, which are is subjected to distillation in the presence of an aqueous solution of alkali in the third column, where, at a temperature at the top of the column 60-70 ° C and a residual pressure of 75-100 mmHg, an azeotropic mixture of butanol and water is separated, which is separated by exfoliation into water and butyl alcohols, and the cubic residue of the composition is 2-ethyl 1-hexanol, high boilers ponenty, soap, are divided in the fourth column at a temperature in the top of the column 113-115 C and a residual pressure of 82-90 mm Hg st on the bottom product of the composition - high-boiling components, tar, withdrawn from the system, and distillate target 2- ethyl hexanol

Example 1: 1245 g / h of feedstock containing 361.1 g / h of light-boiling components, g / h of 2-ethylhexaiol, 74.7 g / h of ethers, 186.7 g / h of high-boiling components, is fed to Perth column “ The temperature at the top of the column-50 ° C5 residual pressure of 150 mm Hg "Art.

358.6 g / h of light-boiling components are recovered in the distillate, which are removed from the Process, 886.4 g / h of bottom product is fed to the second column, where at a temperature in the top of the column is 105 ° C and the residual pressure is 20 microns Hg . 179.9 g / h of the bottom product — high-boiling components discharged from the system

In the distillate, 706.5 g / h of 2-ethylhexanol-extract containing 610 g / h of 2-ethylhexanol, 6.4 g / h of light-boiling components, 7154 g / h of esters, 18s4 g / h of high-boiling components, which are rectified are recovered in the presence of 48.3 g / h of an aqueous solution of alkali (40%) with a reflux number of 15, a temperature in a cube of 120 ° C, at the top 60 ° C, a residual pressure of 75 mm to obtain 68.5 g / h of distillate, stratifying into 39 , 5 g / h of butanol and 29.0 g / h of water supplied from the system, and 686.3 g / h of the cubic residue of the composition - 6.4 g / h of light-boiling components, 1.5 g / h of butanol, 605, 0 g / h, 2-ethylhexanol, 18.4 g / h high kokip boiling components, 55.0 g / hr msh which is rectified at a reflux ratio of 1, bottom temperature of 130 C., at the top of a residual pressure of 82 mm rtost "obtained 560.0 g / h

3

2-ethylhexanol, 6.4 g / h light kit

components, 1.5 g / h of butanol, 6.0 g / h of HIGH-BELTED components

The degree of extraction of 2-etxhexano is 89.9 wt.%

After dehydration, 31.6 g / h of butanol are obtained with a basic substance content of 98.5% by weight. The degree of conversion of the esters to butanol is 95.6% by weight,%

PRI me R 2 „1000 g / h of raw material containing 290 g / h of light-boiling components. 500 g / h of 2-ethylhexanol, 60 g / h of esters, 150 g / h of high-boiling components, are served

in the first column Temperature at the top of the column 55 C, residual pressure 200 mm Hg, I

In the distillate, 288 g / h of low-boiling components are removed, which are removed from the process, vat products of 712 g / h are fed to the second column, where at the temperature at the top of the column

 and a residual pressure of 80 mm pTTST, 114.5 g / h of the bottom product — high-boiling components withdrawn from the system.

In the distillate, 567.5 g / h of raw 2-ethylhexanol containing 490.0 g / h of 2-ethylhexanol, 5.0 g / h of light boiling components, 57.5 g / h are added.

esters, 15.0 g / h of HIGHLY BOILED KOM41 .3g / h of 2-ethylhexanol, 4.3 g / h of light-boiling components, 25.6 g / h

and 598.1 g / h of the bottoms residue, which is rectified with the reflux number 1, the temperature in the cube is 137 C, in 40 the top 111 C, and the residual pressure is 90 mm rost. 508.9 g / h of 2-ethylhexanol, 1.1 g / h of light-boiling components, 13.2 g / h of ethers, 3.6 g / h of high-boiling components are obtained

45

penther, which is rectified in at-35 esters, 1.0 g / h of high-boiling compositions of 38.8 g / h of an aqueous solution of nanoty, which is removed from the system, alkali (40%) at a reflux ratio of 20, temperature in a cube of 125 ° C, at the top, a residual pressure of 100 mm pToSTo to obtain 55.0 g / h of distillate, splitting into 31.7 g / h of butanol and 23.3 g / h of water discharged from the system, and 551.3 g / h of the cubic residue of the composition - 5.0 g / h of light-boiling components, 1.0 g / h of butanol, 486.0 g / h of 2-ethylhexanol, 15.0 g / h of high-boiling components, 44.3 g / h mish, which is rectified with a reflux number of 1.5, perature in a cube 135 ° C, at the top 115 ° C, residual pressure of 90 mm rostrum 455 g / h of 2-ethylhexanol, 2.0 g / h of light-boiling components, 0.5 g / h of butanol, 3.5 g / h are obtained high-boiling components

The degree of extraction of 2-ethylhexanol is 91.0% by weight. After dehydration, 25.4 g / h of butanol is obtained with the content of the basic substance.

50

55

The recovery heat of 2-ethylhexanol is 82.6% by weight.

Rectification of bottoms of butyl alcohols production under the conditions of the known (example 3) method showed that it is impossible to separate 2-ethylhexanol from esters by a clear rectification, which is explained by the proximity of their boiling points and possible aeotropy phenomenon. When treating 2-ethnphexanol raw with an aqueous alkaline solution under rectification conditions (temperature, mass transfer), the esters are converted to butyl alcohol.

98.0 maso%

The degree of conversion of esters into butanol is 95.8 May,%

Example 3 (in accordance with a known method, for comparison). 1232.0 g / h of feedstock containing 357.3 g / h of light-boiling components, 616.0 g / h of 2-ethylhexanol, 73.9 g / h of esters, 18A, 8 g / h of high-content components, served in the first column Temperature at the top of the column 60 Cj, residual pressure 150 mm

RTOST

358.4 g / h 15 light-boiling components are removed in the distillate, which are removed from the process, the bottom product 873.6 g / h is fed to the second column, where at a temperature at the top of the column 120 C and a residual pressure of 20 mm 203.3 g / h of the bottom product — high-boiling components withdrawn from the system;

In distillate, 670.3. G / h of 2-ethylhexanol raw containing 25,589.2 g / h of 2-ethylhexanol, 5.4 kg / h is recovered.

low-boiling components, 60.2 g / h of esters, 15.5 g / h of high-boiling components, which are rectified at a reflux number of 10, a temperature in a cube, the top is 95 ° C, a residual pressure of 100 mm pToSTo

72.2g / h light fraction containing

41.3g / h 2-ethylhexanol, 4.3 g / h light-boiling components, 25.6 g / h

35 esters, 1.0 g / h of high boiling components, which are removed from the system,

and 598.1 g / h of the bottoms residue, which is rectified with the reflux number 1, the temperature in the cube is 137 C, in 40 the top 111 C, and the residual pressure is 90 mm rost. 508.9 g / h of 2-ethylhexanol, 1.1 g / h of light-boiling components, 13.2 g / h of ethers, 3.6 g / h of high-boiling components are obtained

35 esters, 1.0 g / h of high boiling components, which are removed from the system,

45

35 esters, 1.0 g / h of high boiling components, which are removed from the system,

50

55

The recovery heat of 2-ethylhexanol is 82.6% by weight.

Rectification of bottoms of butyl alcohols production under the conditions of the known (example 3) method showed that it is impossible to separate 2-ethylhexanol from esters by a clear rectification, which is explained by the proximity of their boiling points and possible aeotropy phenomenon. When treating 2-ethnphexanol raw with an aqueous alkaline solution under rectification conditions (temperature, mass transfer), the esters are converted to butyl alcohol.

and soap. This increases the temperature difference between the boiling point of 2-ethylhexano-l and the water-butanol heteroazeotropic mixture formed, resulting in a separation of butanol-water in the form of distillate, and the soaps, being volatile products, are removed together with high-boiling components.

The tabLo provides comparative data on the known and proposed methods.

The qualitative composition of the components at each stage of the distribution is given in the scoreboard.

The results are compared with Example 3, carried out under the conditions of a known method using the same initial mixture.

The proposed method provides for the redistribution of products in the process of rectification and the separation of 2-ethyl hexanol from mixtures containing ethers with an increase in the yield of the target products. The degree of extraction of 2-ethylhexanol increases to 89.9-91.0% against 74.8-82.6 % in a known way

At the same time, due to the saponification of the esters (rectification with the loss of alkali) and the release of the resulting butanol as an azeotrope with water, it becomes possible to increase the yield and purity of the separated 2-eTylhexanol, in addition, butanol as the target product. - ethylhexanol does not contain acidic impurities, which are available in the form of VAT residue in the form of cn,

0

0

five

five

0

five

Formula of the invention. The method of separating 2-ethylhexanol from a mixture containing butyl alcohols by multistep distillation under reduced pressure to obtain distilled distillate and bottom product in the first column, which enters the second column, where it is divided into the bottom product recovered from the system, and distillate containing 2-ethylhexanol, which is then subjected to rectification with the release of low-boiling products that are removed from the system, and the bottom residue containing 2-ethylhexanol, which is subjected to rectification with Obtaining 2-ethylhexanol in the form of a distillate, characterized in that, in order to utilize waste production of butyl alcohols by the method of oxosynthesis and increase the degree of extraction of 2-ethylhexanol and butanol from distillation products of this production containing ethers, rectification, containing ethers, rectification of the latter is carried out the temperature in the top of the first column is 50-55 ° C; in the second column it is 105-115 seconds to produce distillate containing 2-ethylhexanol; ethers, high-boiling components, the latter being distilled in the presence of u lochi at a temperature of column top of 60-70 C to give butyl alcohol as distillate, and bottoms, containing 2-ethylhexanol, high boiling components, soaps, the latter is subjected to distillation at a column top temperature 113-115 C,

Table 1

74, 8

98, 9

G 0,002

2-Ethylhexanol

82,689,9

96,697,6

0,010,002

91.0

98.7 0.001

Mass fraction of water,%

0.075

Recycled

eight

Continuation of table 1

0.200.08

Butyl alcohol

0.06

Losses

95.5

96.2

9

High-boiling components

Total distiplat

In tocho

Easy Ponents

2-Ethylhexanol Esters

High boiling components

Cubic residue, total

Including

Light bob vschy

Components

2-Ethiphexanol Esters

High boiling coponents

Distillate whole

In t, h,

Lightweight components

2-Ethylhexanol Esters

High boiling components

Butanol +: water

50.3 + 42.4 27.7 + 23.3

1395623

ten

Continued tabl, 2

1and

0.8

Vat residues, total

Boiling components

2-TheseLhexanol

Ethers

High boilers

90.3

- 39, 8 36.0 11, 1 10.0

49.1 44.3

395623

12 Continuation of table 2

0.1

91.6

5.8

485.5

0.8

444.7

28.1

57.9

31.3 17.6

9.0

Claims (2)

SUMMARY OF THE INVENTION A method for separating 2-ethylhexanol from a mixture containing butyl alcohols by multi-stage distillation under reduced pressure to obtain a distillate distillate and a bottoms product in the first column entering the second column, where it is separated into a bottoms product removed from the system and distillate, containing 2-ethylhexanol, which is then subjected to rectification with the release of low-boiling products discharged from the system, and still bottoms containing 2-ethylhexanol, which is subjected to rectification to obtain in the form of 2-ethylhexanol distillate, characterized in that, in order to dispose of butyl alcohol production wastes by oxosynthesis and increase the degree of extraction of 2-ethylhexanol and butanol from bottoms of this production containing esters, rectification containing ethers, the rectification of the latter is carried out at a temperature at the top of the first column, 50-55 C, in the second column, 105-115 ° C to obtain a distillate containing 2-ethylhexanol, ethers, high-boiling components, the latter being rectified in the presence of alkali at perature in the column top of 60-70 C to give butyl alcohol as distillate, and bottoms, containing 2-ethylhexanol, high boiling components, soaps, the latter is subjected to distillation at a column top temperature 113-115 ° C. Table! Indicators Way In a well-known Proposed by Example Famous Example 3 1 2 2-ethylhexanol The degree of extraction, May 7 Mass fraction of the main substance,% Acid number, mg KOH / g 74.8 82.6 98.9 96.6 0.002 0.01 89.9 0.002 91.0 98.7 0.001 Ί Continuation of table 1 Way Indicators In a well-known 9 Proposed by Example Famous | Example 3 1 1. ² Mass fraction of water,% 0,075 1 0.20 0.08 0.06 Butyl alcohol The degree of extraction, May% In recycling Losses 95.5 96.2 Mass fraction of the main substance% No data - 98.5 98.0 Acid number, mg KOH / g No data - 0.01 0.005 Mass fraction of water,% 0.2 0.15 Table 2 Component The proposed method Example 3 in the conditions of the known method Exit Exit % kg / h % | kg / h Distillate total In t »h _about Low boiling components 2-ethylhexanol Ethers High boiling components VAT residue, total In _about Low boiling components 2-ethylhexanol Column 1 288.0 290.9 98.9 285.0 98.2 285.7 1,1 3.0 0.5 1,5 - - 1.3 3,7 - - - “712.0 709.1 0.7 5,0 0.6 4.3 69.8 497.0 70.3 498.5 I Continuation of Table 2 Component The proposed method Example Sv conditions of a known method Exit Exit " X kg / h ....... kg / h Ethers 8, 4 60.0 7.9 56.3 High boiling components 21 150.0 21,2 150.0 Column 2, Dnetillat, total In tocho Low boiling components 2-ethylhexanol Ethers High boiling components 567.5 544.1 1,0 5,0 0.8 4.3 86.3 490.0 87.9 478.2 10.1 57.5 9.0 48.9 2.6 15.0 2,3 12.7 Kuboy balance, total 144.5 165.0 Including Low boiling components - 2-ethylhexanol 4.8 7.0 12.3 20.3 Ethers 1.7 2,5 4,5 7.4 High boiling components 93.5 135.0 83,2 137.3 Column 3 Distillate total 55.0 58.6 B-.tch Low boiling components 6.0 3,5 2-ethylhexanol 7.3 4.0 57.2 33.5 35.4 20.8 Ethers High boiling components 1.4 0.8 i Butanol + water 50.3 + 42.4 27.7 + 23.3 eleven 1395623 12 Continuation of Table 2 The proposed method Example 3 in conditions Component famous way Exit Exit X 1 1 -------------- 1 1 1 I 1 1 1 1 ί ^d 1! 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1_______________________1 X. G • kg / h VAT residues 1 Ki, total 551.3 485.5 Low boiling point Components 0.9 5,0 0.1 0.8 2-Ethylhexanol 88.1 486.0 91.6 444.7 Ethers - - 5.8 28.1 High boiling point Components 2,8 15.0 2.5 ' 11.9 Butanol 0.2 1,0 - - Soaps 8.0 44.3 - - Column 4 Distillate total 461.0 427.6. In TOCH, Boiling com ponents 1,1 5,0 0.2 0.8 2-ethylhexanol 97.6 450,0 96.6 413.4 Ethers - - 2,5 10.5? High boiling components ents 1,1 5,0 0.7 2.9 Butanol 0.2 1,0 - - VAT residue Total 90.3 57.9 Boiling com ponents - - - - 2-ethylhexanol 39.8 36.0 54.1 31.3 Ethers - - 30,4 17.6. High boiling com ponents 11.1 10.0 15,5 9.0 Soaps 49.1 44.3 - -