SU1035018A1 - Process for isolating methanol - Google Patents

Abstract

1. METHOD FOR ISOLATION OF METHANOL from methanol-methyl acetate waste from the production of polyvinyl alcohol or polyvinyl acetals — methanol-methyl acetate – water – acetaldehyde – crotonaldehyde mixtures, by rectification to obtain distillate –zeotropic mixture of methanol methyl acetate, containing acetaldehyde by distillation, to obtain distillate –zeotropic methyl acetate mixture containing acetaldehyde containing a methane acetate mixture, a mixture of methanol and methyl acetate, and a residue of acetaldehyde. containing impurities acetaldehyde, methyl acetate and crotonic isdehyde, using alkaline treatment and subsequent rectification to obtain distilled methanol with acetal impurities eguid and water and bottom liquid - water containing impurities of methanol and alkaline products, which are removed from the system, characterized in that, in order to increase the purity of the target product, 30-85% aqueous methanol with impurities are treated first with hydrogen peroxide, taken in an amount of 1.5-8.5 equivalents of crotonic aldehyde, then alkali, taken in an amount of 1-6 equivalents of crotonic aldehyde and 1-1.2 equivalents of methyl acetate, further treated product ® is rectified with Highlighted distillate (L ta - impure methanol which is passed through a cation exchange resin KU-2-8 to H - form. 2. Method pop.1, distinguished by the fact that, in order to increase the purity of the target methanol, 0-85% AQUEOUS methanol with impurities is separated from the initial mixture: AD ad / which, after peroxide-alkaline treatment, is subjected to rectification with the production of a distillate — methanol, which is passed through cation exchanger KU-2-8 in H 7Form, and a bottom liquid — 40% methanol with examples of MI, which is additionally rectified either separately or together with the initial mixture to produce a distillate supplied to the stage of separation of 80-85% aqueous methanol a, and a bottom liquid containing water and impurities of alkaline treatment products and methanol, which is removed from the system.

Description

This invention relates to organic synthesis, in particular, to an improved method for the recovery of methanol from methanol methyl acetate. production waste of polyvinyl alcohol or polyvinyl acetals - mixtures of methanol - methyl acetate - water acetaldehyde - crotonaldehyde.

A method is known for separating methanol from the initial mixture, composition, wt.%

0.3

13.8

i44,8

0.1 41.0

processing it with 2 wt.% sodium metabisulfite (dry or as a solution) and subsequent distillation at a cube temperature of 98-100 ° C, column top 5b-58 ° C, reflux ratio 2-2.5 to obtain a distillate - a mixture of methanol, methyl acetate, sulfur dioxide (formed as a result of partial decomposition of sodium metabisulfite) and water, composition, wt.%:

75 24 0.4 0.6

and the bottom of the liquid is water containing up to 5.7% by weight of bisulfite compounds of aldehydes and up to 1% by weight of methanol, which is diverted to sewage treatment plants. By treating the distillate with the first column with a 3-4% aqueous solution of caustic soda at the rate of 1% dry by weight of the mixture and subsequent distillation at a cube temperature of 98-100.c., The top of the column 5b-58 ° C, reflux ratio 2-2.5 a distillate is obtained - a methanol-methyl acetate mixture containing impurities of acetaldehyde and water, composition,% in May:

Adetaldehyde0.004

24,496

Methyl acetate

75.0 Methanol

Water0,5

and the bottom liquid is water containing up to 6% by weight of sodium sulfite and sodium acetate, and up to 1% by weight methane, which is diverted to wastewater treatment plants. Extractive distillation of the distillate of the second column at a bottom temperature of 93-95 0, top of the column 52-54 ° C, reflux ratio of 1.5-2, and a ratio of water (extractant) and nutrition equal to 2.5: 1 gives the distillate — azeotropic a mixture of methyl acetate and water containing up to 5 wt.%

methanol, and the bottom liquid: m. - 13% methanol, which is subjected to rectification in another column at a cube temperature of 98-100 ° C, top of the column 61-62 ° C, reflux ratio of 2.5-3 to produce distillate - methanol and bottom liquid containing up to 1 wt. .% methanol, which is recycled to the extractive distillation stage.

Methanol obtained by this method contains up to 0.003 wt.% Acetaldehyde, up to 0.08 wt.% Water, and withstands the test for permanganate sample for 40-50 minutes. Methanol yield

5 from theory 96.35% G1 J.

This method, although it provides high quality methanol, but the process itself is characterized by a high consumption of sodium bisulfite, which in the process decomposes to caustic soda and sulfur dioxide, which requires the use of equipment from special steels, as well as a large consumption of alkali, which affects the cost of the target tonnage. industrial product.

There is also known a method for the separation of methanol from the methanol fraction of the composition, wt.%:

Up to 0.1 up to 2.0 up to 0.1

Degid To 0.5 Else

by distillation at a cube temperature of 66-68 ° C, top of the column 54-56 ° C, reflux number 30-50 with obtaining 40 distillate composition, wt.%:

Up to 2

Acetaldehyde

50-70

Methyl acetate

28-48

Methanol

and bottom liquid, composition, wt.%: Acetaldehyde. Up to 0.02 Methyl acetateTo 0.03

0 Crotonaldehyde Do O, 1

Up to 0.5 Water

o Methanol Else

which is treated with a 3O aqueous alkali solution, taken in an amount of 3-4% by weight of methanol. By distillation of the treated mixture at a cube temperature of 75-78 ° C, top of the column 65-65.5 ° C, a reflux ratio of 0.5-1, a distillate is obtained — methanol containing water up to 0.5% by weight and bottom liquid of the basis, wt. %: methanol 50-60; A 30% aqueous solution of 50–40 gels, which is rectified at a temperature of 5 ° C of 105 ° C, top of the column is 6565, with a reflux ratio of 3 to obtain a distillate — methanol containing water up to 0 May. liquids - 30% aqueous solution. alkali, which, after separation from the resin, is recycled. The resulting methanol is recrypted at the temperature of the bb-cb cube, the top of the column, with a reflux number of up to 4, to obtain a distillate — methanol and a bottom liquid — methanol containing water up to 10 wt.% And the croton aldehyde microfusion mixture, which is recycled . The methanol obtained by this method contains up to 0.006 wt.% Dehydrous acetal, up to 0.1 wt.% Of water, and withstands the test for permanganate carbon dioxide for 35-45 minutes. The output of methanol from the theoretical 98% L21. However, even in this case, the method is technologically difficult due to the need for alkaline treatment of the methanol fraction, the separation of methanol from an alkaline-treated mixture for the separation of tarred aldehydes from an alkaline solution and the distillation of methanol. The closest in technical essence to the present invention is a method for the separation of methanol by distillation of the initial mixture of composition, wt. 0.03-0.06 Acetaldehyde. 7-12 Methyl acetate 53-63 Methanol Crotonic Up to 0.03 aldehyde 30-40 at. the temperature of the TZ-Tb C cube, column top 54-5b ° C, reflux number up to 5 to obtain a distillate - from an orop mixture of methyl acetate-methanol containing acetaldehyde, composition, wt.%: 0.3-0.4 Acetaldehyde Methyl acetate Methanol and the bottom liquid - aqueous methanol containing impurities of acetaldehyde, methyl acetate, crotonaldehyde, composition, wt.%: 0.006-0.008 Acetaldehyde 0.08-0.12 Methyl acetate Methanol Crotonic To 0.03 aldehyde 33-45 which is treated with 0.1% alkalis about the weight of the mixture and rectified at that. the bottom of the cube is 101-105 s, the top of the column is 65 s, the reflux number is up to 4 to produce distillate methanol and the bottom liquid is water containing salt, alkali, tarred aldehydes and up to 0.1 wt.% methanol, which is removed from the system . The meta NOL obtained by this method contains up to 1.0.1 wt.% (In terms of acetone) aldehydes, up to 0.2 May,% (in terms of acetic acid) of esters, up to 0.5 wt.% Water and not withstands the permanganate test. The output of methanol from the theory of 98% Sz. However, the consumption of alkali - 0.1% by weight of the processed mixture, the shortage of g dl. complete tarification of aldegns p, as a result of which the aldehydes enter the target product, methanol. Regenerated aldehyde-containing methanol cannot be used at the stages of vinyl acetate polymerization, preparing methanol solutions of phosphorus and alkali, and using polyvinyl acetate (PVA) lacquer, distilling off monomer from PVA lacquer (in case of polymerization with incomplete conversion) at the stages of dilution, proc Polyvinyl alcohol from sodium acetate leads to staining of polyvinyl alcohol and polyvinyl acetals obtained on its basis, the products of condensation of aldehydes. Crotonaldehyde impurity is especially harmful. In the production of polyvinyl butyral for optical purposes, fresh methanol (GOST 2222-78) is used for optical purposes, containing: Grade 1 Top grade Mass fraction of water,%, not more than 0.05 Mass fraction of aldehydes and ketones in terms of acetone,%, not more than 0.003 Test with potassium permanganate, min, not less than 60 The aim of the invention is to increase the purity of the target product - methanol when it is separated from methanol-methyl acetate waste from the production of polyvinyl alcohol or polyvinyl acetal d - methanol – methyl acetate – water – acetaldehyde – CROTON aldehyde mixtures. This aim is achieved in that according to a method of separating methanol from the methanol - methyl water - acetaldehyde - crotonic aldehyde by distillation with polucheniI it distillate - azeotropic mixture of methyl acetate - methanol containing acetaldehyde, and the bottom liquid aqueous methanol containing an impurity B atsetgshdegida, methyl and crystalline aldehyde using alkaline treatment and subsequent rectification to obtain a distillate of methanol with acetalde admixtures and water and a bottom liquid - water containing mixtures of methanol and alkaline products, which are removed from the system, 30–85% aqueous methanol with impurities is removed with hydrogen peroxide in an amount of 1.5–8.5 equivalents of creto aldehyde and alkali in the amount of 1-6 equivalents of crotonic aldehyde and 1-1.2 equivalents of methyl acetate / after which the treated product is subjected to rectification to obtain distillate - methanol with acetaldehyde impurities and water, which is passed through g of K-2-8 ationite form. To ensure higher purity of methanol released, it is expedient to separate from the initial mixture 80-85% aqueous methanol with impurities, which, after peroxide-alkali treatment, are subjected to rectification to obtain distillate-methanol, which is passed through cation exchanger KU-2 -8 in the H-form, and bottoms liquid — 40% methanol, containing an impurity of alkaline products, which is additionally rectified either alone or together with the initial mixture to produce a distillate that is sent to the release stage 80-85% - fresh water of methanol, and a bottom liquid, containing water and impurities of alkalis hydrochloric processing products and impurities methanol to toruyu withdrawn from the system. When treating an aqueous solution of methanol with hydrogen peroxide and alkali, crotonaldehyde and partially acetaldehyde are oxidized to acids, which are neutralized by alkali. The role of the latter is to catalyze the decomposition of hydrogen peroxide and the oxidation of aldehydes. The use of a cation exchanger permits the coupling of acetaldehyde impurities in methanol to dimethyl acetal. The presence of the latter does not affect subsequent use. The proposed method for the separation of methanol with a relatively simple instrumental and technological design of the process allows to obtain methanol at the level of the requirements of GOST 2222-78 with an aldehyde content of not more than 0.003 wt.% And a permanent sample of 30-65 minutes. The yield of methanol from the theoretical 98%. Dimethyl acetal present in the methanol released in an amount of 0.02-0.045 wt.% Does not adversely affect the polymerization process of f4 J vinyl acetate and is stable in an aqueous-alkaline medium. Thus, the methanol released by this method from methanol-methyl acetate waste can be used at all stages of the production of polyvinyl alcohol or polyvinyl acetals, in particular, polyvinyl butyral for optical purposes. FIG. Tables 1 and 2 show the technological separation of methanol from methanol-methyl acetate waste from the production of polyvinyl alcohol or polyvinyl acetals. Scheme I (Fig. 1). The initial mixture of 1 composition, wt.%: 0.02-0.06 Acetaldehyde 4.5-12 Methyl acetate, Crotonic 0.014-0.035, aldehyde 64-65 is subjected to rectification in a column 2 125-28 theoretical plates) to obtain a distillate - azeotropic mixture methyl acetate-methanol containing acetaldehyde, 3 composition, May. % 0.3-0.4 Acetaldehyde 60-78 Methyl acetate 22-40 Methanol and. the bottom liquid - aqueous methanol containing impurities of acetaldehyde, methyl acetate and crotonic aldehyde 4 composition, wt.%: 0.004-0.01 Acetaldehyde 0.05-0.15 Methyl acetate 30-85 Methanol Crotonaldehyde 0.015-0.04 Water15-70 Column 2 operation mode. 68-83 C Cube temperature 54-56 ° C Top 6-15 Reflux Number Cubic liquid 4 is treated at SO-BO with and mixing with hydrogen peroxide and alkali. In the mixer 5, the bottom liquid 4 is mixed with hydrogen peroxide 6, from where the mixture flows into the reactor 7, where the alkali solution 8 is fed. The consumption of hydrogen peroxide in the form of a 30% aqueous solution (GOST 177-77) is 1.5-8.5 ( mainly 5.5) equivalent by

crotonaldehyde. The consumption of alkali (caustic soda) in the form of a 40% aqueous solution (GOST 2184-77 grade PP) 1-6 (mostly 3) is equivalent to crotonic aldehyde and 1-1.2 equivalent to methyl acetate.

The processing time of the mixture with hydrogen peroxide in the presence of alkali is from 15 to 30 minutes.

After treatment, mixture 9 is subjected to rectification in column 10 (2528 theoretical plates) to produce distillate methanol 11, which is passed through apparatus 12. filled with cation exchanger KU-2-8 in H-form at a rate of 10 to obtain the desired product 13.

The bottom liquid of the column 10 is water containing salts and alkali in an amount of O DB- 2, 7 wt.% And methanol to 0.1 wt.%, 14 are removed from the systems. The mode of operation of the column 10: Cube temperature, ° C 100-103

0

65

top, C

1.5-5

Reflux number

To cationic

After cation treatment (11) processing (13)

Acetalde guide

Dimethyl acetal

Ketyl acetate

Methanol

Thief

Permanganate sample, Methanol, separated according to the scheme, has the composition, wt. Scheme II (Fig. 2). Isolation of methanol from methyl acetate-methanol wastes is carried out as in Scheme 1, only the bottom water of the column 2 - 80-85% aqueous methanol 4 is fed to hydrogen peroxide and alkali, and the mixture 9 after treatment is subjected to distillation in a column of 10 s. obtaining distillate methanol 11 and bottom liquid 40% aqueous methanol containing salts and alkali in the amount of 0.65-1.7 wt.%, 14. The operating mode of the column 10. The temperature of the bottom, 78-80 ° C top, s 65 Reflux number 1.2-1.5 Cubic liquid 14 is subjected to | rectification in column 15 (25-28 theoretical tons relocs) to give a distillate - methanol containing impurity acetaldehyde, 16 which is combined with the starting mixture 1 and

0.01-0 / 019

0,016-0,067

99,814-99., 874

To OD

sample, min 30-50

0,012-0,021

0.024-0.043

0.01-0.067 0.01-0.067 9.814-99.867 99.783-99.86 to 0.1 To 0.107 17-40 31-52

After cation exchanger

Before cation treatment (13) processing (11)

0.02-0.038

0,016-0,067

99,788-99,857

To 0.107

45-65 recieves in xxon 2, and the bottom liquid — water containing CoV r ° ' h < > ° C to 0.1 wt.%, / ° discharged from the system. “Mixtures of water over 20% by weight of the initial f are subjected to rectification. in column 15 to obtain distilled - a - mixtures of acetaldehyde, methyl acetate, methanol, crotonaldehyde containing 13-17 wt.% water, 16, which is rectified in column 2, and the bottom water - water, containing salt and alkali in the amount of 0, 13-1.5 wt.% And methanol - up to 0.1 wt.%, 17, which is removed from the system. The operation mode of the column is 15. The temperature of the cube, from 100-103 tops, from 65-68 0.5-2 Reflux number Methanol released according to scheme I.I. has the composition, in% by weight:

Example 1. The process is carried out according to the described scheme t. The original mixture of 1 composition, wt.%:

0.059

11,954

73,919

0.033 14.035

is subjected to rectification with obtaining distillate - aerootropic mixture of methyl acetate - methanol containing acetaldehyde, 3, and a bottom liquid - aqueous methanol containing impurities of acetaldehyde, methyl acetate and crotonic aldehyde, 4 composition, wt.%:

0.01

0.149

82,891

0.04 16.91

Operation mode COLUMNS Cube temperature, ° С

top, C

Reflux number Addetaldehyde Dimethyl acetal Methylaetat Methanol Permanganate pr The material balance is in tab. 1. Method 2. The process is as in example 1, only liquid 4 is treated with 8, hydrogen peroxide valents Acetaldehyde Dimethyl Acetal Methyl acetate Methanol Water Permanganate sample Material balance in tab. 2

Cubic liquid 4 is treated at a temperature of 40 ° C and mixing of the research Institute of hydrogen peroxide 6 and alkali 8.

The consumption of hydrogen peroxide is 1.5 equivalents of crotonic aldehyde (0.03% of the amount of the mixture) in the form of a 30% aqueous solution.

The consumption of caustic soda is 1 equivalent of crotonaldehyde and 1 equivalent of methyl acetate J0, l% of the amount of the mixture) in the form of a 40% aqueous solution.

First load the hydrogen peroxide solution, then the alkali solution. The processing time of the mixture with hydrogen peroxide in the presence of alkali is 15 minutes.

A mixture of 9 psle after processing is subjected to distillation to obtain a distillate — methanol containing an admixture of: and acetaldehyde and methyl acetate, 1 and a bottom liquid — water containing methanol to 0.1% by weight, salt and alkali, 14, which is removed from the system . The mode of operation of the column 10.

The temperature of the cube.

100-103 top, 65 ° C

Reflux. the number 1 / 5-2 Distil t 11 is passed through a layer of cation exchanger KU-2-8 in the H-form at a temperature of 40 ° C, at a rate of 10 m7 MCH, while acetaldehyde is bound in dimethyl acetal.

The methanol produced has a composition

O. wt.%: After cationic treatment with cationic treatment (13) (11) 0.067 99.822 99.8C6 0.099 17 tonaldehyde (0.165% of the mixture) and 6 equivalents of caustic soda in crotonic aldehyde and 1 equivalent in methyl acetate (0.356% on the amount of the mixture). The methanol released has a composition, wt.%: Ationite. After cation treatment (11) treatment (13) treatment 0.02 0.04 0.016 0.016 99.865 99.838 0.099 0.106 40 56 Example 3. The process is carried out in example 1, only cube i

Liquid 4 is treated with 1.5 equivalents of hydrogen peroxide over croton aldehyde (0.03% of the mixture) and 6 equivalents of caustic soda for crotonic acidAcetoshdegid Dimethyl acetal Methyl t Methanol Water Permanganate sample, min The material balance is presented in Table. 3. PRI and, MER 4. The process is carried out as in Example 1, only the bottom liquid {liquid 4 is treated with 8.5 equivalents of hydrogen peroxide by cro-acetaldehyde

Dimethyl acetal

Methyl acetate

Methanol

Water

Permanganatna test, 4in

The balance is presented in table. four.

Example 5. The process is carried out as in example 1, only the bottom liquid 4 is treated with 5.5 equivalents of crotonaldehyde hydrogen peroxide (0.11% of the amount of acetaldehyde

Dimethyl acetal

Methyl acetate

Methanol

Water

Permanganate sample, min. Material balance is represented by abl. five.

Example 6. The original mixture of example 1, only with a content of 35 wt.%, Composition, wt.%:

0.044

Acetaldehyde 8,975

Methyl acetate 55,502

methanol

0.025 35.454

guide and 1 equivalent of methyl acetate (0.35 €% of the amount of the mixture).

The methanol released has a composition by weight%:

0.021

0.043

0.067 0.067 99.814 99.783 0.099 0.107 25 40

five

va mixture) and 3 equivalents of caustic soda in crotonaldehyde and jl equivalent of methyl acetate (0.145% of the mixture).

The methanol produced has a composition

0 May.%:

cation exchanger

After cation resin (11) treatment (13)

0.013

0.026

0.049 0.049 99.838 99.821 0.1 34 0.104 45

is processed as in example 1, only the bottom liquid 4 is treated as in example 5.

The mode in the distillation columns is maintained such that the degrees of separation are as in Example 1. The operating mode of the columns is 2 "U. Cube temperature, ° C 75 100-103 top, 54 65

Reflux number

5 3 Cubic liquid 4

composition, wt.%: 0,007

Acetaldehyde After cationic ationite treatment (13) processing (11) 0.012 0.024 0.016 0.016 99.873 99.857 0.099 0.103 38 tono aldehyde (0.135% of the amount of the mixture) and 1 equivalent of unit sodium of crotonic aldehyde and 1 equivalent of methyl acetate (0.1% of amount of mixture). . The methanol isolate has the composition, wt.%: Cationic After cationic treatment (11) treatment (13) 0.107 Methyl acetate 59,215 Methanol Cretan aldehyde Water 40,642 is treated with 5.5 equivalents of hydroxy acid in crotonic Acetaldehyde Dimethylacetal Methyl acetate Methanol Permangantet acetraldehyde Dimethylacetal Methyl acetate Methanol Permangantet acetraldehyde Dimethylacetal Methyl acetate Methanol Permangantet acetraldehyde Dimethylacetal Methyl acetate Methanol Permangantricanetromanthropanetricantetetanetromantet acetondehyde Methylene acetaldehyde Water 40,642 is treated with 5.5 equivalents of hydrochloric acid in crotonic acid tab. 6. Example 7. The starting material from Example 1, only with a water content of 65% by weight of the composition, by weight. Acetaldehyde 0.024 4.866 Methyl acetate Methanol 30.096 Crotonaldehyde0.014 Water65.0 is reprocessed as in re 1, only the cubic liquid is processed as in Example 5. Mode B: distillation bottoms are maintained so that the separation penalties are as in p The columns 82-8 Temperature cuba, C top, Reflux number Acetaldehyde Dimethyl acetal Methyl acetate Methanol Permanganate sample, min Material balance presented In Table. 7 Example 8. The process is carried out according to scheme II. The original mixture 1 from example 1 composition, wt.%:

, 059 11.954 73.919

0.028

98,978

0.994 guide (0.077% of the amount of the mixture) and 3 equivalents of caustic soda for crotonaldehyde and 1 equivalent for methyl acetate (0.1% of the amount of the mixture). The methanol released has a composition, wt.%: After cationic onite ki (11) treatment (13) 0.026 1 0.01, 99.86 877 0.104 52 Cubic liquid 4, composition, may.%: Acetaldehyde 0.004 Methyl acetate 0.054 Methanol 30.094 Crotonic 0.015 aldehyde 69.833 is treated with 5.5 equivalents of hydrogen peroxide for crotonaldehyde (0.04% of the mixture) and 3 equivalents of caustic soda for crotoid aldehyde and 1 equivalent for methyl acetate (0.055% of the amount of the mixture). The selected methanol has the composition, in% by weight: After cation-exchanger cation treatment (13) testing (11) 0.01 99.877 Crotonic 0.033 aldehyde 14.035 together with recycled methanol stream 16, composition, wt.%: Subjected to distillation to obtain distillate azeotropic mixture methyl acetate - methanol containing acetaldehyde, 3 and bottoms liquid aqueous methanol containing 4% by weight with acetaldehyde, methyl acetate and crotonic aldehyde, wt.%: 0.009 Acetaldehyde 0.133 Methyl acetate 84.611 Metaiol Crotonaldehyde 0,036 Water15.211 Work pattern -70 tempera travel cube C on the top, 54 C reflux ratio of 6-7 bottoms liquid 4 I process temperature and by mixing at a temperature of 40 6 SRI hydrogen peroxide and alkali Flow rate of hydrogen peroxide - 5 equivalents of crotonic Alde (0.1% of the mixture). Acetaldehyde Dimethyl Acetal Methyl Acetate Methanol. Permanganate sample, min Cubic liquid 14 is subjected to distillation to obtain distillate — methanol with admixtures of acetas dehydide 16, which is sent to recycling — to the stage of rectification of the feed mixture, and bottled liquid of water containing methanol to m salt and alkali, 17, which output from the system. The mode of operation of the column 15. The temperature of the cubic, C 100-10 top, p. 65-66 Reflux number 2 The material balance is presented in Table. 8. Example 9. The initial mixture from example b composition, wt.%; 0.044 Acetaldehyde Methyl Acetate 8.975 55,502 Methanol Crotonic 0.025 Aldehyde 35.454 Consumption of caustic soda 3 equivalent of crotonic aldehyde and 1 equivalent of methyl acetate {0.13% of the mixture). First, the hydrogen peristication solution is loaded, then the alkali solution. The processing time of the mixture with hydrogen peroxide in the presence of alkali is 5 min. After treatment, mixture 9 is subjected to distillation to obtain distillate — methanol, containing acetaldehyde and methyl acetate, 11, and bottom oil — 40% aqueous methanol, containing salt and alkali, 14. Column operating mode 10. Cube temperature, From the top, ° C Reflux Distil t 11 is passed through a layer of cation exchanger KU-2-8 in the H-form at a temperature with speed. . 10, while acetaldehyde is bound to dimethyl acetal. Methanol has a composition. May.%: Ionite After cationic (11) treatment (13) 0.022 0.049, 841 99.826 0.103 60 together with the bottom liquid of the methanol recovery column 14, May.% Water 59.102 Methanol39.993 Salt (alkali 0.905 is subjected to rectification to obtain distillate - mixtures of acetyldehyde, methyl acetate, methanol, crotonic aldehyde and 13 wt.% water 16 composition, wt.%: Aichetaldehyde 10.878 Methypacetate Tat 76.173 Methanol Crotonic 0.030 aldehyde 12.863 and bottom water - water containing methanol to 0.1 wt.% , salt and alkali, which is removed from the system. Column operation mode 15.

Cube temperature, from 100-103

top, ° C 65-68 Reflux Number Up to 0.5

The distillate 16 is subjected to rectification to obtain a distillate of azeotropic methyl acetate – methanol containing acetaldehyde, 3 and a bottom liquid – aqueous methanol containing acetaldehyde, methyl acetate and crotonic aldehyde impurities, 4% by weight:

Acetaldehyde

0.009 0.133

Letyl acetate

Before cation treatment (11) Acetaldehyde Dimethyl acetal. Methyl acetate Methanol Water Permanganate sample, min. The material balance is presented in Table. 9. Example 10. Initial mixture 1 from example 7 composition, wt.%: 0.024 Acetaldehyde 4.866 Methyl acetate 30.096 Methanol Crotonaldehyde together with the bottom liquid of the column evolving methanol 14 composition, may.%: Water59,102 Methanol39.993 45 Salts + alkali 0.905 is subjected to distillation with obtaining distillate - a mixture of acetaldehyde methyl acetate, methanol, crotonic 50

Before cation treatment (11) sample, min

Materia LNI balance presented

in tab. ten.

84,605

Methanol

Crotonic

0.036

aldehyde 15,217

Water

The mode of operation of the column 2. Temperature tank, ° C 68-70

top, ° C

54

6-7

Reflux number

Cubic liquid 4 is treated with hydrogen peroxide and alkali and rectified as in example 8.

The methanol released has a composition of 15% by weight:

After cation treatment (13), 0.04– 99.8 0.09–45 alva and st

After cation treatment (13)

0; 011

0.022

0.049 0.049 99.841 99.826 0.099 0.103 45 60 0.022 0.049 9 99.826 41 0.103 9 60 Ådehyde and 13% by weight of water, 16%, May%:, Acetaldehyde Methyl acetate 10.878 Methanol 76.173 Crotonic aldehyde 0.030 12.863 cubic liquid - water, contain 1 methanol / liter. Oh, May 1. % salt and salt, 17, which is derived from siema. The mode of operation of the column 15. The temperature of the cube, ° C 100-103 top, from 65-68 Reflux number To 0.7. The distillate 16 is processed by dividing methanol as in Example 9. The methanol recovered is E.e.%: Rectification starting material. Initial mixture 1 750.84 100.0 Including: 0.44 0.059 acetaldehyde 89.75 11.954 methyl acetate 555, 02 73,919 croton methanol 0.25 0.033 aldehyde 105.38 14.035

750,84

Total:

Processing the water-methanol fraction with hydrogen peroxide and alkali (reactors 5 and 7) and rectification of the treated mixture (column 10)

to

623.191100.0

0.0610.01

0.93OD49

516,5782,891

0,250,040

105,3816,91

isi

0.607100.0

0.182

0.425 1.615

and 8,

Table 1

517,646 100.0

t 11,

0.012

0.062 erg 0.067 0.345

Tat 99.822 516.729

0.51

0.099 100.0

liquid 14, 107,767

98,736

106,426

0.086

0.093

30.0

1,158

1.248 70.0

Christmas tree 100.0 months (column 2) 127.649 100.0 Distillate t 3 including: Kubova liquid 4, 623.191 100.0 including:

0.646 40.0 0.969 60.0 625.413

Cationic treatment of methanol (apparatus 12)

Methanol before treatment (11) 517.646 100.0 including: acetal aldeg id methyl acetate 516.729 99.822 methanol 0.51 0.099 water 517.646 Total:

The distillation of the initial mixture (column 2) - the same balance as in example 1 (see table. 1)

Treatment of water-methanol stock with hydrogen peroxide and alkali (reactors 5 and 7) and rectification of the treated mixture (column 10)

to

629,191 100.0

0.061 0.01 0.93 0.149 516.57 82.891

0.25 0.040 105.38 16.91

isi

100.0

3.437 30.0 1.031

kind of

Continued table. one

625,413

Total:

Methanol after treatment 13 W.h .: 517,646 100.0

Table 2

517,539 100.0

0.102O 02

0.0850.016

516,84299,865

0,510,099

Cubic liquid 14, 114,637 100.0 including:

111,473 97,240

water 0.093 0.081 methanol 0.1270.025 dimethyl acetal 0.3450.067 methyl acetate 516.63999.806 methanol 0.5350.102 water 517.646 Total

including

The distillation of the initial mixture (column 2) - matbalais is the same as in example 1 (see table. 1)

Treatment of water-methanol fraction with hydrogen peroxide and alkali (reactor 5 and 7) and rectification of the treated mixture (column 10)

flax

623,191 100.0

0.061 0.01 0.930.149

516.57 82.891

0.040

0.25 105.38 16.91

Kishi

100.0

0,607

Continued tobl. 2

Table

517,498100,0

0.0610.012

0.0850.016

516,84299,873

0.510,

Cubic liquid 14, 111,848 100.0 incl. 2,219 40,0 alkali 3,329 60,0 water 629,346 Total: methanol (apparatus 12 Cationic treatment Methanol before processing 517, 498 100.0 Ki 11, including: 0.061 0.012 acetaldehyde 0.085 0.016 methyl acetate 516.842 99.873 methanol 0.510.099 517.498 Total:

The distillation of the initial mixture (column 2) - the same balance as in example 1 (see table. 1)

Processing the water-methanol fraction with hydrogen peroxide and alkali (reactors 5 and 7) and rectification of the treated mixture (column 10)

Water-methanol fraction 4,

623,191 100.0

including:

0.061 0.01 acetaldehyde

0.93 0.149

methyl acetate 516.57 82.891 methanol

croton

0.25 0.040 aldehyde 105.38 16.91

water

Continued table. 3 Mebo in di me

Table 4

517,694 100.0

0.11

0.021

0.345 0.067 516.729 99.814

0.51 0.099 pts 14, 110.549 100.0 629.346 total: a) thanol after processing, 498100.0 13, including: 0.1250.024 methyl acetal 0.0850.016 tilacetate 516.75399.857 tanol 0, 5350,103 517,498 Total:

and

3.437100.0

1,03130,0

Yes

2,40670,0

1,615,100.0

eight,

0.64640.0

0.96960.0. 628,243

Cationic treatment of metaiol (apparatus 12)

Methanol before treatment (11) .517,694 100.0

0.11 0.021 0.345 0.067 516.729 99.814 0.510.099

The distillation of the initial mixture (column 2) - the same balance as in example 1 (see table. 1)

Treatment of water-methane fraction with hydrogen peroxide and alkali (reactors 5 and 7) and rectification of the treated mixture (column 10)

flax

623,191 100.0

0.01

0.061

OD49

0.93

516.57

82,891

0.25

0.04

Continuation of taOl four

0,093 0,084 109,005 98,603 1,451 1,313

628,243

Total:

Methanol after treatment (13) 517,694 100.0

0.225 0.043 0.345 0.067 516.569 99.783 0.555 0.107

Table 5

istil t 11,

517,599100.0

including

0.0660.013

acetaldehyde

0,2540,049

methyl acetate

516.76999,838

methanol

0,51,0,1

water

isi

2,226

100.0

30.0

0.668

genus 1.558 70.0

and 8, 100.0 2.26

0.904 40.0 1.356 60.0 627.677

Cationic treatment of methanol (apparatus 12)

Methanol before processing (11) 517,599 100.0

0.0660.013

0,2540,049

516.76999,838

0.510.1 517.599

:

Rekti (1mkatsi initial mixture (column 2) 1, 1000.0 100.0 Distillation t 3,

including:

0.44 0.044 acetousdehyde

89.75 8,975 methyl acetate

555.02 55,502 methanol

Continued table. five

108,326 98,408 0,093 0,085 1,659 1,507

627,677

Total;

about517, 599100,0

0,1350,026

0,2540,049

516,67399,821

0.5730,104 517,599

Table 6

127,649100.0

0,3790,297

88,8269,581

38.4530,122

0.25 0.025 354.54 35.454

1000.0

Total:

Processing the water-methanol fraction with hydrogen peroxide and silk (reactors 5 and 7) and rectification of the treated mixture (column 10)

to

872,351 100.0

0.061

0.007 0.107 0.93

516.57 59.215

th aldehyde 0.25 0.029 354.54 40.642

354.54

peroxide

2,226,100.0 6,

0.668

30.0

hydrogen 1,558 70,0 100,0

alkali 8, 2.26

40.0

0.904

1,356 60.0 876,837

Total: Methanol to Ki (11),

including:

0.0660.013 acetaldehyde

Continued table. 6

872,351 100.0

4,

0.061

0.007 0.93 0.107

516,5759,215

0,250,029

degid

354.5440,642 1000.0

),

517.227100.0

0.0660.013

0.0510.01

516,699,877

0.510.1

item 14,

359,61100.0

357,4999,411

0,350,097

1,770,492

876,837

Total:

517.227 100.0

including:

0.135 0.026 dimethyl lal tal Cationic treatment of methanol (apparatus 12) with Methanol after treatment, 227 100.0 treatment (13),

Rectification of the initial mixture (column 2) Initial mixture 1, 1844.17 100.0 Distil t 3,

Including t

scalaldehyde

methyl acetate

methanol

crotonaldehyde

1198.71 65.0

water

1844.17

Total:

Processing the water-methanol fraction with hydrogen peroxide and alkali (reactor 5 and 7) and distillation of the treated mixture (column 10)

Water-methanol

fraction 4,

including:

acetaldehyde

methyl acetate

methanol

crotonaldehyde

Continued table. 6

Table 7

127,649 100.0

0,3790,297

88,8269,581

38.453022 t 4, 1716.521 100.0

0.0610.004

0,930,054

516.5730.094

dehyd 0,250,015

1198,769,833 1844.17

516,427,100.0

0.066

0.013

joanmectap

then

teio.%

g

1198.71 69.833 2.226 100.0 Cationic treatment of methanol (the methanol sample apparatus is the same as in the example.

Rectification of the initial mixture together with recycled ELM methanol stream (column 2)

one,

750,84100,0

0,440,059

89,7511,954

555.0273,919

crotonaldehyde 0,25 0,033

105.38 14.035

water

Recyclable

methanol stream 16, 74,471 100.0

0.0210.028

73,7198,978

0.740,994 825,311

The Proposal 7

“Aeya

ioteir

- "

liquid 14, 1204.58 100.0

1201.66 99.758 1.15 0.095

0.147

1.77

127.67 100.0

0.313

0.40 69.570 82.82 30.117 38.45, 697.641 100.0.0, 4,

0.061

0,009

0.133

0.93

84,611

590.28

0.25

0.036

dehydde

106.12

15.211

825,311

: 1721,007 12) -matbalance and permanganate 6 (Table 6) .., Table 8 Processing (Water-methanol reactors 697.641100.0 fraction 4, including 0.0610.009 acetal & dehyd 0.930.133 methyl acetate 590,2884,61 methanol 0,250,03 crotonaldehyde 106,1215,21 Hydrogen peroxide solution b 2,226100,0 including; hydrogen peroxide water. Alkali solution 8, including j Alkali Total: Cationic treatment Me Methanol before treatment (11), 517.589 100.0 including J 0.056 0.011 acetaldehyde 0.254 0.049 methyl acetate 516.769 99.841 methanol 0.51 0; 099 water Total: 517.589 Distillation of bottom liquid methanol (column 15) Cubic liquid of the separation column 184.538 100.0 methanol 14, including 8

Continued table. 8 water-methanol fractions with hydrogen peroxide and alkali 5 and 7) and rectification of the treated mixture (column 10) Distillate 11, 517.589 100.0 including: 0.056 0.011 acetalde guide 0.254 0.049 methyl acetate 516.769 99.841 methanol 0.51 0.099 Kubova liquid 14, 184.538 100.0 including: 109.066 59.102 73.803 39.993 methanol 1.669 0.905 salts + alkali Total; 702,127 (apparatus 12) tanol after processing TJOT (13), 517,589100.0 including. 0.115O, .022 methyl acetal 0.2540.019 thiladetate 516.68899.826 tanol 0.5320.103 517.589 Total: columns of extraction of steel stills 16, 74.471100.0 including: 0.0210.028 crude dehydrate

109,066 59,102 73,803 39,993 1,669 0,905

184,538

Total: Rectification of the starting mixture by combining methanol (column 15)

Initial mixture 1,

1000.0 100.0 incl.

184,538100,0

109.06659.102

73.80339,993

1.6690.905 1184,538 Aeotropic mixture separation. Distillation of organic components from MeP Continued t abl. 8TCTl 0.74 0.994 110.067 100.0

fluid 17,

108.32698.418

0.0930.085

1,6481,497

Christmas night 184,538

Total:

Tblcc 9

825.047 100.0.

0.461 0.056 89.75 10.878 628.466 76.173 0.25 0.030

dehyd 106,12

Be 17, 359.491 100.0

357.486 99.443 0.357 0.099 1.648 0.458

1184,538

Total: the bottom liquid of the column methyl acetate - methanol (column 2) Distil t 3, 127.67 100.0

s

825.047100.0

0,4610,056

89,7510,878

628,46676,173

cretonic aldehyde 0,250,030

water106.12 12.863

825,047

Total:

The material balance of the process from the water-methanol fraction

Rectification of the initial mixture together with the bottom liquid of the methanol recovery column (column 15)

one,

1844.17 100.0

0.440.024

89,754,866

555.0230.096

0,250,014

eguid

1198,7165.0

b and

184.538 100.0 109.066 59.102

Continued table. 9

0.4000.313

88,8269,570

38.4530,117

697,377100,0

item 4,

0.061 0.009 0.930.133

590,016 84,605 0,250,036

dehydde

106.12 15.217 825.047

distribution of methanol 4 (tab. 8)

ten

Table

824,254 100.0

0.461 0.056 89.75 10.889 627.673 76.15 0.250.030

dehydde

106.12 12.875

St17, 1204,454 100.0

i: 01, 656 99,768

1, 095

73,803 39,993 1,669 0,905 2028,708 Note:

Continued 1gabl. ten

1,648 0.137

salts + alkali 2028,708

Total: Material balance of the process of methanol extraction from distillate 16 - (see tab. 9 and 8)

Claims (2)

1. METHOD OF ISOLATION OF METHANOL from methanol-methyl acetate waste products of the production of polyvinyl alcohol or polyvinyl acetals - a mixture of methanol - methyl acetate - water - acetaldehyde -. Crotonic aldehyde, by distillation to obtain a distillate - an azeotropic mixture of methyl acetate, methanol, acetaldehyde, water and acetaldehyde, and containing impurities of acetaldehyde, methyl acetate and crotonaldehyde, using alkaline treatment and subsequent distillation to obtain distillate - methanol with impurities of acetaldehyde water and bottoms liquid - water containing impurities of methanol and alkaline products, which is removed from the system, characterized in that, in order to increase the purity of the target product, 30-85% aqueous methanol with impurities released from the initial mixture is treated first hydrogen peroxide taken in an amount of 1.5-8.5 equivalents for crotonic aldehyde, then alkali taken in an amount of 1-6 equivalents for crotonaldehyde and 1-1.2 equivalents for methyl acetate, then the processed product is rectified ?, with isolation dis tillate - methanol’s impurities, which are passed through KU-2-8 cation exchange resin in the H ⁺ form. 2. The method of pop. 1, characterized in that, in order to increase the purity of the target methanol, -80-85% aqueous methanol with impurities is isolated from the initial mixture, which is subjected to rectification after peroxidation treatment to obtain distillate - methanol, which is passed through KU cation exchange resin -2-8 in Н ⁺ ; -form, and bottoms liquid - 40% methanol with impurities, which is additionally rectified either separately or together with the initial mixture to obtain distillate fed to the separation stage of 80-85% “aqueous methanol, and bottoms containing water and impurities of alkaline products and methanol, which is removed from the system. SU „„ 1035018>