SU566822A1 - Method of purifying acetic acid - Google Patents

Description

rotated in column 1 for irrigation in the form of phlegm.

The bottom liquid of the column 1 is sent to the second distillation column 4, from which, in the form of a distillate, after cooling,

the refrigerator 5 is taken regenerated acetic acid.

Example 1. Technological parameters for carrying out the regeneration process of acetic acid are given in Table. one.

Table I

In the power of the column 1 serves water in the amount of 0.8 kg / hour, and in the cube of the column 1-0.8 nl of nitrogen per 100 liters of acetic acid.

The material balance of distillation coloins 1

As can be seen from the results of the material balance table. 2, when using 0.8 nl of crotonaldehyde nitrogen, acetic acid is not blown off, the crotonaldehyde fraction is sent to incineration. The distillate of distillation column 1 in a Florentine vessel 3 is stratified into organic and aqueous phases. The latter is discarded as waste.

In tab. 3 shows the material balance of Florentine 3.

The bottom liquid of the distillation column 1 in the amount of 100.086 kg / h is fed to the distillation column 4, where regenerated acetic acid is recovered as a distillate, and the bottom liquid is further evaporated, after which the bottom balance of the column 1 is given in table. 2

table 2

the evaporator current is directed to incineration.

The material balance of the distillation column 4 is presented in table. four.

Example 2. Technological scheme and parameters of the rectification process are similar.

example 1.

Nitrogen in the amount of 0.05 nl per 100 l of acetic acid is fed to the bottom of the column 1. At the same time, the content of crotonic acid increases in the bottom liquid of the distillation column 1.

aldehyde to 0.056% by weight, whereas in distillation distillation column 4, the content of crotonaldehyde increases to 0.058%, indicating an insufficient amount of nitrogen and a low purity of the target acetic acid.

The material balance of distillation column 4

Example 3. Technological scheme and parameters of the rectification process are similar to example 1.

50 nl per 100 liters of acetic acid is fed to the bottom of the column 1. The content of crotonaldehyde in nitrogen removed from column 1 is 2.1% by weight and 0.024% in regenerated acetic acid.

Example 4. Technological scheme and parameters of the rectification process are similar to example 1,

Table 3

Table 4

70 nl of nitrogen per 100 liters of acetic acid is fed to the column. The nitrogen removed from the column 1 contains 4.6% of crotonaldehyde by weight and 0.024% in regenerated acetic acid, which indicates that an increase in the amount of nitrogen supplied does not affect the quality of the target product.

Example 5. Technological scheme, parameters of the rectification process and the amount of nitrogen fed to the cube of the column 1 are similar to example 1, except for the purity of acetic acid supplied for rectification and the amount of water,

Material balance of the distillation column 1

Material Balance of Florentine 3

Example 6 (comparative). Technological conditions and process parameters are similar to Table 5

Table 6

Example 1 with the exception of the purity of the supplied acetic acid and the amount of water, 8 In table. Table 5-7 shows the material balances of columns 1 and 4, as well as Florentine 3.

910

The material balance of the distillation column 4 The process is carried out without supplying nitrogen, i.e., as in the lime process.

Material balance of the distillation column 1

Example 7. The process conditions and process parameters are similar to example 1, the composition and amount of acetic acid, as well as the amount of water are similar to example 6.

The process is conducted in the presence of 0.76 nl of nitrogen.

In tab. 10 and And shows the material balances of distillation columns 1 and 4.

As can be seen from examples 6 and 7, in suggestion 566822

Tabl.a 7

Table 8

In this way, acetic acid is purified to a crotonaldehyde content of 0.023% (at 99.357% concentration) versus 0.182% (at 99.78% concentration).

In addition, the loss of acetic acid with the crotonaldehyde fraction is lower than in

The known method is -4.4% versus 5%. In tab. 8 and 9 show the material balances of columns 1 and 4.

Ii.

The material balance of distillation column 4

Material balance of the distillation column 1

566822

Table 9

Table 10

Material balance of the rectification column 4

Claims (2)

1. A method of purifying acetic acid from impurities formed during the synthesis of vinyl acetate by two-column distillation in the presence of water, characterized in that, in order to increase the degree of purification Table ll acetic acid and its release, the process of distillation lead by filing 0.1-50 nl of nitrogen per 100 liters of acetic acid in the cube of the first distillation column. 2. The method of claim 1, wherein nitrogen is supplied in an amount of 0.8 nl per 100 liters of acetic acid. Nutrition Nitrogen / 7i, fncrMi / e Regenerated Acetic, fucj oma