TW386076B - Method for recovering acrylic acid - Google Patents

Description

Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs _ 38S0TI .Rev .; Γ! 7, Invention Description η 88. 9, i Supplement without j 1. Schematic illustration; Figure 1 is the first specific of the invention The flowchart of the example is a pseudo-distillation operation to obtain high-purity acrylic acid. Fig. 2 shows the process of the second embodiment of the present invention, which is awake, like obtaining high-purity acrylic acid through a double distillation operation. 2. Symbols of components 1 ~ 1 5 、 .2 1 ~ 3 6. • Flow line 10K 201. • Acrylic collection column 102 > 2 0 2- • Azeotropic separation column 103 λ 2 0 3 ·. • Solvent recovery Column 104 > 2 0 4 " • High azeotropic substance separation column 20, 40… Storage tank _24a- (Please read the precautions on the back before filling this page) The silver scale of the paper is applicable to the Chinese National Standard (CNS) A4 * Grid (21 OX297 mm) A7 B7 printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the Invention (Production) This invention is about the method of recovering acrylic acid. More particularly, the present invention relates to a method comprising collecting acrylic acid in the form of an aqueous solution by contacting acrylic acid with propylene and / or propylene to obtain a gas-phase catalytic oxidation using molecular oxygen-containing gas, And distillation of acrylic acid aqueous solution in the presence of the specified azeotropic solvent to effectively isolate and recover acrylic acid. The manufacture of acrylic acid by gas-phase catalytic oxidation of propylene and / or acrolein has been widely practiced in the industry. This method generally includes an oxidation step to catalytically oxidize propylene and / or acrolein using molecular oxygen in the gas phase, a collection step to collect the acrylic acid-containing gas generated by the gas phase catalytic oxidation by contacting the gas with water, and a recovery step to freely The aqueous solution of acrylic acid obtained in the collection step isolates and recovers acrylic acid. The acrylic acid-containing gas contains 畐! I products such as acetic acid, formic acid, acetaldehyde, and formaldehyde, among which acetic acid is a relatively large amount. Therefore, in order to produce high purity acrylic acid, acetic acid must be removed. However, attempts to remove acetic acid from acrylic acid by distillation tend to induce polymerization of acrylic acid due to the high distillation temperature required. (The boiling point of acetic acid is 1 18 · G ° C). There is also another problem. The small volatility values of acrylic acid and acetic acid make it difficult to separate by simple distillation. As a result, as to the isolation and recovery of high-purity acrylic acid from the aqueous acrylic acid solution, that is, separation of acrylic acid from acetic acid and water to recover high-purity acrylic acid substantially free of acetic acid and water, a method is generally adopted which is used in the presence of an azeotropic solvent in The aqueous acrylic acid solution was distilled in an azeotropic separation column. This method includes the use of a three-component azeotropic distillation consisting of acetic acid-water-solvent, and the distillation of acetic acid, water, and solvent in the top of the azeotropic separation column. -3-This paper applies Chinese national standards (CNS ) A4 size (210X 297mm) (Please read the notes on the back before filling this page)%

、 1T A7 B7 Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs ^ V. Description of the invention () > 1 1 Boiling mixture and recovery of acrylic acid from the bottom of the column 0 Impurities other than acetic acid 1 I v 1 is easy to remove and -fnr m requires Relying on azeotropic distillation 9 because they all have a low boiling point. 1 For example > Β This patent official bulletin published Sh 0 6 3 (1 98 8)-1 0 6 9 1 Teach one / --- ', Please first use this azeotropic distillation method 9 It uses a hydrocarbon such as toluene as a co- Boiling solvent 0 Read 1 Β This patent official bulletin published Sh 0 4 6 (1 97 1)-3 4 6 9 1 Sh 0 4 6 (1 9 7 1) Back f I 1 -1 8 9 67 Display method & gt It uses butyl acetate dibutyl m, ethyl butyrate 1 # 1 Ν Gengyuan • V ethyl methacrylate, propyl acrylate, etc. as azeotropic solvents. Item | Re | Japanese Patent Official Bulletin Announces He i 6 (1 9 9 4)-1 5 4 9 6 Instructions--Use this to fill in this -ΠΓ azeotropic solvents such as butanol acetate Λ methyl isobutyl ketone Method for carrying out azeotropic distillation page ____ 1 I 0 1 1 In addition 1 Japanese Patent Official Bulletin He i 5 (1 9 9 3)-2 4 6 9 4 1 Show 1 1 1 method 1 which uses at least one member to select white Including diethyl ketone, methyl acetone, methyl 1-butyl isobutyl ketone methyl, second butyl ketone and n-propyl acetate, and at least one member selected from the group consisting of toluene S heptane and methyl cyclohexane as an azeotropic solvent 1 I Agent 0 1 I However, according to the method known in the present research, the following various 1 1 problems occurred: Plant ′ In J ρ Sh 〇 6 3-1 0 6 9 1 The method of patent teaching, the separation of acetic acid 1 Insufficient I The acid separation column requires 1 1 double separation operation to separate acetic acid. In addition, 9 because of the insoluble water-soluble azeotropic solvent such as toluene that exists near the bottom of the azeotropic separation tube 1 I, such as toluene, the liquid separation in the column The two phases of the oil-forming and aqueous layers are both 1 1 to prevent the polymerization inhibitors from dissolving uniformly and make acrylic acid with a higher concentration distributed in the water phase easier to polymerize. 0 I I use JP S hc 4 6-3 4 6 f 1 patent and J 4-PS h 〇- 1 8 96 7 Patent teaching 1 1 1 1 1 1 This paper size applies to Chinese National Standard (CNS) AWL grid (IMOX 297 mm) Printed by A7 B7 of the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs When the azeotropic solvent shown in the description of the invention ("), a high-purity acrylic acid product cannot be obtained in a single distillation operation because the separation of any one of acetic acid, water, and solvent is insufficient. If the use of the azeotropic solvent shown in the J P He e 6-1 5 4 9 6 patent causes problems, insufficient separation of the solvent in the azeotropic separation column and the mixing of the solvent into the recovered acrylic acid. In the method of recovering high-purity acrylic acid by a single distillation operation as described in JPH e. 5-2 4 6 9 4 1 A 1 again, acrylic acid is present in the azeotropic separation column at a high concentration, especially in the middle. From the plate to the upper plate, the polymerization tendency of acrylic acid in the column cannot be ignored. ^ When the polymerization force of acrylic acid in the azeotropic separation column is so high, the acrylic polymer accumulates in the tube and makes the long-term azeotropic separation tube It is difficult to carry out the column continuously. Therefore, the object of the present invention is to solve the above problems encountered by the prior art. More particularly, the object of the present invention is to provide a method comprising, when introducing an aqueous acrylic acid solution into an azeotropic separation column and dehydrating by azeotropic distillation, preventing polymerization of acrylic acid in the column and distillation from the top of the column Acetic acid in the form of an azeotropic mixture of acetic acid-water-solvent, and high purity acrylic acid substantially free of acetic acid was recovered from the bottom of the column with high efficiency. According to this research, it has been found that the above object of the present invention can be accomplished by using an azeotropic solvent, including using at least one member selected from the group consisting of ethyl acrylate, methyl methacrylate, ethylene acrylate, allyl acetate, and isopropyl acetate. , Vinyl propionate and methylcrotonate; and at least one selected from the group consisting of toluene, heptane, 1-heptane, methylcyclohexane, cycloheptane, cycloheptadiene, cycloheptatriene, 2, Mixed solvent of 4-dimethyl-1, 3-pentadiene, methylcyclohexene and methylenecyclohexane, as azeotropic solvent; preferably -5-this paper size applies to Chinese national standard soap (CNS) Λ4 specification (210X297 mm) (Please read the precautions on the back before filling this page)

'1T A7 B7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the Invention (4) 1 Contains at least one of ethyl acrylate and methyl methacrylate > and a mixture of toluene and at least one of heptane 1 1 1 alkane Solvent 〇 According to the above method of the present invention, by a method * = i = > It contains a gas-phase catalytic reading of propylene and / or acrolein collected by contacting the gas with water first. 1_ Oxidation Acrylic gas-containing QM body in the form of an aqueous acrylic acid solution obtained at the time and 1 I-1 This aqueous acrylic acid solution is introduced into an azeotropic separation column and distilled in the presence of an azeotropic solvent 1 boxing 1 9 to isolate and recover acrylic acid & gt This method is characterized in that item 1 is filled with at least one solvent A with a mixed solvent containing the following, which is selected from the group consisting of C At least one solvent B, ethyl acetate, methacrylic acid page, -1 methyl ester, vinyl acrylate m, allyl acetate, isopropenyl acetate 1 1 vinyl propionate and methyl crotonic acid 5 and 1 1 It is selected from the group consisting of toluene, heptane, 1-heptane, 1-methyl methyl hexane cycloheptane cycloheptadiene N hexaheptadiene 2, 4-dimethyl-1yl-1, 3-pentadiadiene , Methylcyclohexene and methylenecyclohexane. 1 I as an azeotropic solvent. This method is hereinafter referred to as the first specific embodiment of the present invention. Example 1 The first specific embodiment of the method of the present invention is characterized in that the aqueous acrylic acid solution is introduced into an azeotropic separation tube. Column and in the presence of azeotropic solvents 1 | Distillation for separation and recovery of acrylic acid J Mixed solvents containing the above specified solvents A 1 1 and B solvents are used as azeotropic solvents 〇 Use of specified mixed solvents 1 I is effective Anti-acrylic polymerization of acrylic acid on azeotropic separation column 〇 1-! 1 degree If the result of using the specified mixed solvent 9 can be used only αο 単 one distillation operation 1 i Distillation of acetic acid \ water and solvent and High purity acrylic acid with substantially no acetic acid was recovered at the bottom part 1 of the white tube column. Therefore, according to Zhao Benfa 1 1 6 1 1 1 1 National Standards (CNS) A4 specifications (210X297 mm) A7 B7 Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention ()-Specific embodiments 1 The aqueous acrylic acid solution can be distilled in an azeotropic separation column Isolation and recovery when there is substantially no acetic acid 9 local purity acrylic acid 9 At the same time-to prevent the polymerization of acrylic acid 〇 Please specify the solvent under Group A »Preferably use ethyl acrylate and methyl methyl acrylate > and Group B As the solvent, toluene and heptane are preferred. Therefore, as a preferred example of the mixed solvent, the following propylene can be specified. Note the following propylene acetate ethyl toluate + toluene toluene + ethyl acrylate + methyl methacrylate + item Toluene, methyl methacrylate + heptane) ethyl acrylate + methacrylic acid Methane + Toluene > Ethyl acrylate + methyl methacrylate + heptane 9 Page 1 1 and methyl methacrylate + toluene + heptane 0 1 1 This ethyl acrylate, methyl methacrylate toluene and Heptane can be obtained by industry > It can be used without further treatment. The blending ratio of solvent A and solvent B ranges from 10 9 0 to 7 5 2 5 9 1 and preferably 2 0 8 0 to 5 0 5 0 Weight ratio 0 When the ratio of solvent A is too local 1 1 The acetic acid concentration at the bottom of the azeotropic separation column increases > making it difficult to pack 1 I Distillation step White water acrylic acid solution recovery essentially • firr Μ Acetic acid purity 1 1 Acrylic acid 0 When the proportion of solvent B is too high, the liquid in the azeotropic separation column separates into oil phase and water phase 5 and it becomes difficult to prevent the polymerization of acrylic acid. 1 I have also found a method) which includes at least one member of ethyl acrylate 1 1 methyl methacrylate-allyl acrylate, allyl acetate isoacetate 1 I azeotrope of propylene vinyl propylene vinyl and methyl crotonic acid The use of solvents, namely, I described the solvent A, and only 9 caused the recovery of high-purity acrylic acid. According to this method, two distillation operations were used to obtain high-purity acrylic acid. That is, 9 white total 1 I bottom extraction column containing acetic acid 7 Zhi Ψ citrus acrylic, demon / VS, later introduced it 1 1 1 1 1 This paper size applies Chinese National Standards (CNS) Λ4 present (210 x 297 mm) A7 B7 Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Preparation of the invention 5. Description of the invention (b) 1 Acetic acid separation column to remove acetic acid. Therefore, > According to the present invention, i. Provide a method for recovering acrylic acid, i. Aqueous propylene and / or acrolein are catalyzed by gas-phase oxygen. The aqueous acrylic acid solution formed when the acrylic acid gas obtained is -1, the water is read into the azeotropic separation column and distilled in the presence of an azeotropic solvent. Back 1 I 1 Isolation and recovery of acrylic acid It is characterized by the use of items selected from the group consisting of ethyl acrylate 1 1, methyl methacrylate, vinyl acrylate allyl acetate acetate | re 1 isopropenyl vinegar, vinyl propionate At least one solvent of esters and methyl crotonic acid is used as a script 1 i is an azeotropic solvent. This method is hereinafter referred to as the first embodiment of the present invention.-Page 1 I Example 0 1 1 According to the first embodiment of the present invention Ethyl acrylate and methacrylic acid as azeotropic 1 1 solvents in the method Methyl acetate, vinyl acrylate S 1, allyl acetate, isopropyl acetate N, vinyl propionate, and methyl crotonic acid 1 can be industrially available, they can be used without any further treatment. Its 1 I methyl group The methyl acrylate is preferably 〇1 I _____. The specific examples are conveniently used in the following steps to prepare a commercial purity propylene 1 1 enoic acid in a gas phase catalytic gasification step of propylene and / or propylene using a molecular oxygen-containing gas Acrylic acid-containing gas 1 W obtained by gas-phase catalytic gasification from the water-collecting step. The aqueous solution obtained in the collecting step. 1 1 Acrylic acid solution isolation and recovery. Acrylic acid recovery step and acetic acid separation. 1 I step to separate and remove impurities such as impurities. Acetic acid 01 contained in acrylic acid 1 obtained in the recovery step] The figure illustrates the first embodiment of the present invention. Flow chart »Recovery of high-purity acrylic acid by 1 Μ C3 mouth distillation operation 〇 In the first figure, the number 1 1 8 1 1 1 1 This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) A7 B7 Consumption cooperation by employees of the Central Bureau of Standards of the Ministry of Economic Affairs 5. Printed invention description (7)-1 Γ 1-1 5 indicates the flow line 〇1 〇1 indicates the acrylic collection tube string, 1 0 2 indicates 1 1 azeotropic separation tube string ] 0 3 represents a solvent recovery column, 1 0 4 represents an azeotrope, 1 mass separation column, and 20 is a reservoir. 0fV Please 1 «-First, the present invention will be explained in accordance with the steps described in Fig. 1. AA * Read it in detail 1 I Example method 〇1 I-1 Caution in the gas-phase catalytic oxidation of propylene and / or acrolein with molecular chlorine 1 Acrylic acid gas containing fist 1 is introduced into acrylic acid via line 1 Collect the column 10 1, item • 4 of the manuscript 1, which is connected to the htsi and the water introduced through line 2. The warp 4 extracts the aqueous acrylic acid solution containing 1 ί acrylic acid and by-products such as acetic acid. Collected from it i 1 The gas of acrylic acid is discharged through line 3 and recycled to the oxidation reaction step 〇1 1 Occasionally a part of the gas is discharged as gaseous waste after entering the combustion step i 1 0 Although the acrylic acid collection pipe string is introduced through line 2 1 1 Water can be supplied by warp 1 and route 1 3. 9 It is preferable to use a white solvent recovery column 10 3 1 as described below. Aqueous acetic acid solution discharged from the bottom. This aqueous acrylic acid solution is introduced into the column 1 1 azeotropic separation column. 10 2. Normally, no mediation process is required. However, if 1 I needs it, it can be introduced into the propylene m light rod discharge column (not shown) first to remove the propylene m dissolved in 1 1 and then introduced into the azeotropic separation column 10 2 0 in the latter Γ case & gt The released propylene m is conventionally recovered and recycled to the reaction system. 1 1 In an azeotropic separation column 1 0 2, an aqueous acrylic acid solution via lines 4 and 1 1 an azeotropic solvent via line 5 > and distillation is performed. 0 An azeotropic mixture of acetic acid, water and a total of 1 1 boiling solvents. Distillation via line 6 on top of white column 5 and f Extraction from bottom of white column substantially fiir Acrylic acid-free acrylic acid 〇1 Feed to azeotropic separation column 1 〇2 Aqueous acrylic acid solution composition 1 I Sight line 2 The amount of water supplied to the acrylic collection pipe string 1 0 1 and other operations 1 1 1 9 1 1 1 1 This paper size applies to China National Standards (CNS) A4 specifications (210 X 297 cm) A7 B7 Staff consumption of the Central Standards Bureau of the Ministry of Economic Affairs Cooperative print 5. Description of the invention (8)-1. Operation changes 0 and conventionally used acrylic manufacturing conditions, usually a composition of 1 includes 9 acrylic acid 50-80% by weight acetic acid 2-5% by weight; and Water 1 I 20 -4 0% by weight (100% by weight in total) 〇 '— 、 Please first \ An azeotropic mixture consisting essentially of acetic acid S water and an azeotropic solvent 9 its reading back 1_ via line 6 white azeotropic separation column 1 0 2 distillation at the top, introduced into the reservoir 2 〇〇1 I 1 The mixture is separated into an organic phase mainly composed of an azeotropic solvent in the reservoir. 1 Things 1 and ΐ an aqueous phase composed of acetic acid and water. 0 The organic phase is routed through a circuit. 5 Recycling term | 2. At the same time, the aqueous phase was introduced into the solvent via line 8 to recover and fill in the uncoated tubing column 103. In the solvent recovery column]. 0 3 1 An azeotropic solvent evaporates from the top of the column 1 I distills and returns to the reservoir 2 via line 9 0 »At the same time, it is composed of acetic acid and water 1 1 Aqueous acetic acid solution via line 1 4 White column 1 0 3 Bottom extraction and discharge system 1 In order to effectively use this aqueous acetic acid solution, it can be recirculated to the acrylic acid collection tube column 1 as described above. Line 1 1 Feeding acrylic acid-containing gas 0 1 I White azeotropic separation column 1 0 2 Bottom extraction of substantially acetic acid-free propylene 1 | Acid> High purity acrylic acid j can be sent to the esterification step via line 15 as 1 1 The starting material of acrylic acid ester 矣 ′ In order to obtain a higher purity acrylic acid product, the acrylic acid extracted from the bottom of the azeotropic separation column 10 2 1 1 can be introduced into the high boiling substance separation column 10 7 1 1 and Distillation 0 As an azeotrope of polymerization inhibitors White 12 10 4 1 I a bottom portion of the column tube 1 and the extraction of relatively pure propylene acids 03 m line U from the top of the recovery column tube. 1 1 The operations in the above steps can be performed under conditions known for this type of treatment. 1 For example, 9 Under the following conditions (at stable operation), perform azeotropic separation in the column 1 0 2 1 1 to obtain Contains no more than 0.05% by weight of high purity acetic acid I 1 -1 0-1 1 1 1 This paper size applies to China National Standard (CNS) A4 (210X297 mm) Employees' Cooperatives of the Central Bureau of Standards, Ministry of Economic Affairs Print A7 B7 5. Description of the invention (f) Degree of acrylic acid. Operating pressure: 1㈣-200mm mercury

Temperature at the top of the column: 4 5-5 5 ° C Temperature in the aqueous acrylic acid solution supply part (aqueous solution supply plate):

7 0-9 0 ° C

Temperature at the bottom of the column: 1 0 0-] 1 0 ° C reflux ratio (total moles of reflux fluid per unit time / total moles of distillate per unit time: 1.1-1.6 Knowing the practice, it is recommended to add a conventional polymerization inhibitor to prevent the polymerization of acrylic acid in the azeotropic separation tube column 102. According to the flow chart in Figure 丨, a high purity acrylic acid is obtained through a single distillation operation, as in the present invention. The first specific embodiment eliminates the use of an acetic acid separation column and produces the advantages of simplifying the acrylic acid manufacturing method and significantly reducing the cost of acrylic acid manufacturing. 'Figure 2 of the accompanying drawings depicts the method of the second specific embodiment of the present invention, in which a double distillation High purity acrylic acid is recovered by operation. In the second drawing, 2 1-3 6 are flow lines; 2 01 is an acrylic acid collection column; 202 is an azeotropic separation column; 2Q3 is a solvent recovery column; 204 is an acetic acid separation column. 2 (35 is a column for separating azeotrope substances; and 40 is a reservoir. The method of the second embodiment of the present invention is explained below according to the flowchart in FIG. 2. Use of a molecular gas-containing gas in propylene and / or acrylic acid Of Acrylic acid-containing gas obtained during phase-catalyzed gasification is introduced into the acrylic acid collection pipe string via line 2 1—1 1-This paper size applies to China National Standard (CNS) A4 specification (210 '× 297 mm) (Please read the precautions on the back first (Fill in this page again) '袈 ·

、 1T V. Description of the invention (The route is connected to its A7 B7, such as pumping 4 2 The route is to pass liquefied dissolved gas from 0 water to cyclic cyclic water recirculation and discharge of 23-line linear acid After receiving the ethyl body such as gas and its acid allyl allyl, it can be obtained from this. The gas such as 20 after the column flash tube step burns the burning acid into the propylene into the body to introduce -LV 2 gas 2 The line part of the road passes through one but it is 0. The water draining and discharging part of the waste water is discharged in a step-by-step manner. The bottom line 3Γ Line 20 The column is a tube to collect water and the solvent can be dissolved. The supply of water is better than the first 2 ο-2 The first column can control its 0, it needs to be co-fruited if it needs to be boiled, and it is liquid and soluble in acid. After all, the acrylic water-saving water treatment will still need to be volatile. (Please read the precautions on the back before filling out this page.) It is shown in the following: 2/20 loop column, then column separation, and tube separation and release of boiling back release of co-aldehyde. Among the allyls, the latter is the one that dissolves the release of the aldehyde allyls. Service material 20 enters the column 25 The pipeline is separated off by boiling agent co-solvent in boiling co-solvent 4 2 route via liquid capacity >, / 1 acid allylic water agent boiling and co-solving with water by distillation XI / XI Into the column tube, the head and the distillation section top column tube white 6 2 0 acid acid ene is mixed with acetic acid and acetic acid mixed with ethyl boiling containing co-extracted extraction group substrates to make other groups of liquid solution Hydrolyzed ene 01 ro Propane water Ministry of Economic Affairs Central Standards Bureau Employees' Cooperatives Printed the next article 2 Column acid tube ene Collected propylene 20 acetic acid Use tube olefin to separate the tube propylene to the aliquot And a total of 22. The improvement of the route to the feed line is considered as including the weight of the package. The group usually passes water and the weight is 5-2 acid ethyl 0%) The weight% is 80 weight I ο ο ο acid co-propylene W boiling group Ξ * Agent 21 is to be dissolved 2 The main boiling column is co-piped away and separated. The water is dissolved by boiling and blending. The solution is stored in the middle spring, and its phase is 00. The main paper and the size of this paper apply the Chinese National Standard (CNS) A4 specification (210 × 297 mm) A7 B7 Printed by the Consumers 'Cooperative of the Ministry of Standards of the People's Republic of China. 5. Description of the invention (1 1)', 1 aqueous phase composed of Γ. The organic phase passes through the line 2 5 to the azeotropic separation column 2 0 2 1 I 7 Simultaneous aqueous phase Introduce the solvent recovery column 2 0 3 through the line 28. At the solvent recovery 1 column 2 3, the azeotropic solvent is distilled from the top of the column and returned to the storage device 1 through the line 2 9. The wastewater is passed through the line 3 4 White tube column 20 3 bottom extraction and discharge system read 1 f 〇 In order to use it effectively, this water can be recycled to the back via line 3 0 as described above 1 ¾ 1 I 1 acrylic acid collection column 2 η 1, Contact via line 2 1 Acrylic acid containing feed Note 1 Fist 1 Gas term I Re I White azeotropic separation column 2 0 2 Acrylic acid containing warp with acetic acid extracted at the bottom fill in this installation path 2 7 Introduce acetic acid separation column 2 0 4 to remove acetic acid. The separated acetic acid was removed from the top of the column 2 0 4 through page 1—1. At the same time, 1 1 acrylic acid containing substantially no acetic acid was recovered at the bottom of the same column. Because the recovered acrylic acid has been highly purified! 5 It can be used as the starting material of acrylate. Obviously, the higher purity 1 acrylic acid can be sent to the azeotrope through the line 3 2 and the mass separation column 2 0 5 and the line 3 6 Extract high boilers from the bottom of the column 2 0 5 1 1 such as polymerization inhibitor and via line 3 5 recover higher purity from the top of the column 1 I acrylic acid 0 1 1 In order to prevent azeotropic separation of the column 2 0 2 Polymer formation, usually adding i | polymerization inhibitor. In the present invention > it is also recommended to add the commonly used polymerization inhibitor 1 I formulation 〇1 1 in the second embodiment of the method i ± / ·, boiling The operating conditions of the separation column 2 0 2 1 | The two distillation operations isolate and recover acrylic acid, depending on the individual acetic acid concentration of acetic acid extracted from the bottom of the column, so 1 cannot be specified uniformly. For example, 1 under the following conditions (at the time of stable operation of 1 I) The operation of azeotropic separation column can obtain the concentration of I to 9% by weight. 1 1 I -1 3- 1 1 1 1 This paper size is applicable to China National Standard (CNS) A4 specification (210X297 mm) kl B7 Central Ministry of Economic Affairs Printed by the Consumer Cooperatives of the Standards Bureau. 5. Description of the invention () 1 1 Acid is essentially 4τττ Μ Solvent acrylic acid 〇1 1 I Operating pressure: 1 0 0-2 0 mmHg 1 Top of the column (ππ degrees; 4 5 -5 5 ° C Please first the temperature of the aqueous acrylic solution supply part (aqueous solution supply plate): Read 1 Back 1 4 5 -7 n ° c I 1 1 Temperature at the bottom of the column 9 5 -1 0 5 ° C Note 1 thing 1 reflow fch example (total moles of reflux fluid per unit time / m moles of distillate per unit time and 1 time) 1 • 0 -1 .3 Distillation of crude acrylic acid in an acetic acid separation column to obtain page 1 I local-purity acrylic acid> Under the conventional conditions of this type of distillation, use it. 0 1 1 According to the flow chart in Figure 2 which is obtained by two distillation operations High-purity 1 1 acrylic acid> The above-mentioned __ of the present invention. The specific embodiment method produces excellent 1-order solvent separation power and the advantages of effective prevention of undesired polymer formation. 1 Explained in more detail in the following reference working example this invention. 1 1 —— 丄 1 1 Recover acrylic acid according to the steps described in Figure 1 〇1 1 The gaseous Chu mixture obtained by the gas-phase catalytic oxidation of propylene using molecular oxygen-containing gas is led to the acrylic acid collection column 1 0 1 and contacted with water . The acrylic acid aqueous solution of 1 I thus obtained was guided to a propylene release column (not shown), where 1 1 was charged with propylene m. 0 and the remaining aqueous acrylic acid solution contained: 3〇1 | wt% water With 3.0% by weight of acetic acid. The solution was then placed in a sieve tray with 50 plates each arranged at a regular interval of 114 mm, the 1 1 line was distilled off at the top of the column, the starting material supply line in the center and the bottom portion The bottom 1 I product m was distilled from the azeotropic separation column 10 2 of the pipeline. As for the azeotropic solution 1 1 I -1 4-1 1 I 1 this paper size quick use Chinese National Standard (CNS) A4 specifications (210X297 mm) A7 B7 5. Description of the invention (d) agent, using methyl methacrylate Mixed solvent with toluene (blending ratio: 3 5: 65 weight ratio). As for the polymerization inhibitor, each pair of copper dibutyldithiamineformate with an amount of vaporized acrylic acid vapor of 15 PP m, manganese acetate of 2 2.5 ppm, hydrogen plutonium of 7 5 P pm and 7 5 ppm of Brown wheeze trap. The manganese acetate is supplied to the column from the top of the column in the form of being dissolved in the starting material through the starting material supply line, and other inhibitors in the form of dissolved reflux fluid. Separately, 0.3 vol% of molecular oxygen was supplied to the bottom portion of the column for the vaporized acrylic acid vapor. The amount of vapor evaporated here means the total volume of monomer vapor evaporated from the bottom of the column corresponding to the heat applied by the reboiler of the distillation column. The operating conditions of the azeotropic separation column 102 at stable operation time are: the temperature at the top of the column, 5 fl ° C; the temperature at the bottom of the column, 105 ° C; the pressure at the top of the column, 160 mm Hg, reflux Proportions (total moles of reflux fluid per unit time / total moles of distillate per unit time), 1.3 2; and the aqueous acrylic acid solution is supplied via line 4 at 9.3 liters / hour. The water phase through line 8 contains 7.6 wt% acetic acid and 0.6 wt% acrylic acid. And the line] 5 The fluid extracted from the bottom of the azeotropic separation column 102 contains 96. 9% by weight of acrylic acid, 0.30% by weight of acetic acid and 3.10% by weight of various other components, and also contains Solvents that do not exceed the solvent detection limit (1 PP m). Printed by the Employees' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling in this paper. The aqueous phase obtained through line 8 is introduced into the solvent recovery column 10 3, and the solvent is recovered from the top of the column through line 9 At the same time, the aqueous acetic acid solution was drawn from the bottom of the column via line 14. The solution consisting of 8.1% by weight of acetic acid, 0.64% by weight of acrylic acid, and the rest of the water was recycled to the acrylic acid collection column. 01 Gas-phase mixture obtained by the gas-phase catalytic gasification of propylene by China-Israel contact 1 5-This paper size applies to China National Standard (CNS) A4 specification (2 丨 〇 × 297 mm) Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (β) compound (that is, as a collector for replacing water). When azeotropic separation column 1 Π 2 is continuously performed under specified conditions for about 14 days, stable operating conditions are fixedly obtained. When the inside of the column was inspected after the operation was stopped, there was no sign of polymer formation. The basket was subjected to azeotropic distillation of an aqueous acrylic acid solution in the same manner as in Example 1, except that methyl methacrylate was used alone The azeotropic solvent and reflux ratio were reduced to 1.. 2 4. The aqueous phase in line 8 contained 6.3% by weight of acetic acid and 4.5% by weight of acrylic acid during stable operation time, ie, up to The acrylic acid content is about 8 times. On the other hand, the fluid extracted from the bottom of the azeotropic separation column 10 through line 15 contains 96.2% by weight acrylic acid, 0.3% by weight acetic acid and 3.5% by weight. % Of other various components. Therefore, its acetic acid content is as high as ten times the product of Example 丨. As above, when methyl methacrylate is used as the azeotropic solvent alone, high-purity acrylic acid cannot be recovered from the azeotropic separation column 102. Example 2 An azeotropic distillation of an aqueous acrylic solution was performed in the same manner as in Example 1, except that a mixed solvent of methyl isobutyl ketone and toluene (blending ratio: 6 5: 3 5 weight ratio) was used as an azeotropic solvent and refluxed. The proportion was increased to 1.4 2. The aqueous phase in line 8 contained 6.9% by weight of acetic acid and 0.5% by weight of acrylic acid in stable operation time, and passed through line 15 from the azeotropic separation column 10 2 Bottom extraction fluid contains 96.9% by weight acrylic acid, 0.08 Amount of acetic acid, 0 · Π 0 2% by weight of solvent and 3.02% by weight of other various ingredients 16 — This paper size is applicable to the Chinese national standard (CNS) Λ4 current grid (210 × 297 mm) (please Read the precautions on the back before filling in this page. I., ..-1T printed A7 B7 printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (5) invention description (). In the azeotropic separation column 102 under the above conditions Stable operation may be almost complete when carried out continuously for about 14 days, but when the distillation column was cut and inspected after the operation was stopped, a small amount of popcorn polymer was found in the column. Example 2 An azeotropic distillation of an aqueous acrylic acid solution was performed in the same manner as in Example 1, except that a mixed solvent of ethyl acrylate and toluene (blending ratio: 3 5: 65 weight ratio) was used as the azeotropic solvent. The aqueous phase in line 8 contained 7.3% by weight of acetic acid and 0.5% by weight of acrylic acid during stable operation. The fluid extracted from the bottom of the azeotropic separation column 10 through line 1.5 contained 37.2% by weight of acrylic acid, 0.33% by weight of acetic acid, and 2.8Q% by weight of various other components. Its solvent content does not exceed the detection limit (lppm). When the azeotropic separation column 102 was continuously operated under the above conditions for about 14 days, stable conditions were always maintained. When the inside of the distillation column was inspected after the operation was stopped, no polymer formation was observed. …. Cap — Example — 3_ Perform azeotropic distillation of an aqueous acrylic acid solution in the same manner as in Example], except that ethyl acrylate alone is used as the azeotropic solvent and the reflux ratio is reduced to 2.4.2. The aqueous phase in line 8 contained 6.5 wt% acetic acid and 4.9 wt% acrylic acid at a stable operating time, i.e. up to about 8 times the acrylic acid content in the aqueous phase of Example 1. On the other hand, the line 15 azeotropic separation column-I 7-this paper size is applicable to China National Standard (CNS) Α4 specification (210X297 mm) IJ ---------; · &" Clothing-(Please read the notes on the back before filling in this page)

1, 1T printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (4) The fluid extracted at the bottom contains 96.5% by weight of acrylic acid, 0.3% by weight of acetic acid and 3.2% by weight % Of various other ingredients. Therefore, its acetic acid content was ten times higher than that of the product of Example 1. As described above, when ethyl acrylate is used alone as an azeotropic solvent, high-purity acrylic acid cannot be recovered from the azeotropic separation column 102. Example—3—The azeotropic distillation of an aqueous acrylic acid solution was performed in the same manner as in Example 1, except that a mixed solvent of ethyl acrylate and heptane (blending ratio: 3 5: 65 weight ratio) was used as the azeotropic solvent. And the recirculation ratio is reduced to 1.2. The aqueous phase in line 8 contained 7.6% by weight of acetic acid and 0.5% by weight of acrylic acid during stable operation. And the line] 5 The fluid extracted from the bottom of the azeotropic separation column 10 2 contains 97.1% by weight of acrylic acid, 0.55% by weight of acetic acid and 2.85% by weight of various other components, and also contains Solvents that do not exceed the detection limit (1 PP m). When the azeotropic separation column 102 was continuously operated under these conditions for about 4 days, stable operating conditions were fixedly obtained. When the interior of the tubing was inspected after the operation was stopped, there was no sign of polymer formation. Example 4 An azeotropic distillation of an aqueous acrylic solution was performed in the same manner as in Example 1, except that a mixed solvent of methyl methacrylate and heptane (blending ratio: 3 5: 65 weight ratio) was used as the azeotropic solvent and refluxed. The proportion drops to 1.2 2 4. The aqueous phase in line 8 contained 7.3% by weight of acetic acid and 0.6% by weight of acrylic acid during stable operation. And the fluid extracted from the bottom of the azeotropic separation column 102 via line 15 contains 97.2% by weight of acrylic acid and 0.44% by weight of -18.-This paper size applies the Chinese National Standard (CNS) A4 specification ( 210X2V " 1 conversion) (Please read the precautions on the back before filling in this page).

、 1T V. Description of the invention (A7 B7 parts are CJC species, each other is 0 1% of the dosage of the column, the weight of the dissolution tube is 6 \ 7, 7 S points • P 2 P boiling and U co-acidity have been detected in the B limit inspection The super time does not include 4 1 × at the same time, about 1/1, and then continue to connect the next piece of work should be stopped after the column tube inspection. 〇 The shape of the piece of the track is fixed to the It is impossible to get the solid state at regular time. The internal gas can be obtained as it is. The gas can be contacted with the water-promoting phase and the cylinder tube gas. The priming product M is mixed with the actual amount of the < ζ side content, and then the weight is released. The content is contained in the liquid. The acid in water is mixed with 3 parts of water and the amount of acid in water is the percentage of acid B. The weight is based on the weight of each solution. (Read the precautions on the back before filling this page.) The sieve plate gauge is in the top column of the steam distillation section of the 4-tube SL distillation section. - parts of the bottom portion of the opening portion in a bottom ώ to the column and 1.0 for the off-road tubulointerstitial tube was boiling points from the start of the co-agents of the central tube passage were dissolved in boiling distillate was distilled to 0 so that with the A

、 1T case ratio mixing / 1 Benzene and ester allyl formate mixed with the agent) ο amount of bb-one 131-the amount of gaseous steam allyl is steamed to suppress the use of each agent Both the base and the methylamine sulfide which are aggregated in the base are printed by the central government bureau of the Ministry of Economic Affairs and the Consumer Cooperatives of the Ministry of Economic Affairs. . The portion of the return is divided into the bottom column tube of the steaming section of the hair department to the percentage of oxygen supply to the oxygen supply. The total volume is cfifc and operated for 10 ° between 2 °. The stabilizing column is in the column; the tube ° c is 7 minutes and 4 minutes, and the boiling temperature of the common temperature part of the soil flows back to the mercury meter millipressure tube | 5 «Mo • '10 total hectares are the number of columns. The size of the ear paper is applicable to the Chinese National Standard (CNS) A4 (210X297 mm) A7 B7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention)-1 1 〇 The total amount of distillate per E3D early position time Molar number), 1.1, and aqueous acrylic acid 1 1 I solution is supplied at line 10.7 liters / hour via line 4. 1 is obtained from the top of the column. The aqueous phase contains 1.5% by weight of acetic acid and 0% by weight. % Acrylic acid 0 and white, —N. Please ί The fluid extracted at the bottom of the azeotropic separation column contains 95.1% by weight of acrylic acid Read North 丨 —2.2% by weight of acetic acid and 2.7% by weight % Of various other ingredients 〇 1 1 1 under the conditions of continuous azeotropic separation column for about 14 hours »General idea 1 thing 1 is to maintain stable operating conditions 〇 look at the interior of the column after the masterpiece is stopped Fill in the time item again. 1 1 There is no sign of the formation of poly-η. 0 1 tLM. — Example — Page 1 I Perform azeotropic distillation of an aqueous acrylic acid solution in the same manner as in Example 5. 1 1 Distill 5 Remove T. Use toluene. The bracelet was used as an azeotropic solvent and the reflux ratio was changed to 1 1). 2 0 〇1 The water phase obtained from the top of the column at a stable operating time contains 4.2% by weight of acetic acid and 0.4% by weight of acrylic acid and The flow at the bottom of the column 1 contains 94.1% by weight acrylic acid 1.8% by weight acetic acid and 4.1% by weight 1 I Composition 〇1 1 When the azeotropic separation column is continuously carried out under the above conditions, 9 is about 4 days. ¾7 After the pressure loss in the operation column was observed in the column 3, it makes the operation 1 1 continue to be difficult. The operation was stopped and cut and inspected. 0 The formation of a viscous polymer was found in the column 1 0. The ratio of M. J? L5 „1 f was performed in the same manner as in Example 1 for the aqueous acrylic solution. Boiling 1 distillation 1 In addition to using a mixed solvent of methyl methacrylate and toluene (blending 1 I ratio: 50 50 weight halo ratio) as the azeotropic solvent, the reflux ratio is reduced to 1.01. 1 1 -2 0-1 1 1 1 This paper size is applicable to Chinese National Standard (CNS) A4 (210X297 mm) Printed by the Consumers ’Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Α7 Β7 V. Description of the invention (G) On the line The aqueous phase of 8 contained 7.0% by weight of acetic acid and 1.3% by weight of acrylic acid at a stable operating time, that is, twice as much as the acrylic acid contained in the aqueous phase of Example 1. And the fluid extracted from the bottom of the total separation column 10 by the line 15 contains 96.5% by weight of acrylic acid, 0.50% by weight of solvent and 3.38% by weight. 1 product 4 single-digit series, and the solvent content is 50 times more than that of Example 1. As described above, when a mixed solvent of ethyl methacrylate and toluene containing 6 carbon atoms is used, acrylic acid of satisfactory quality cannot be obtained by a single distillation operation. 1 Comparing 16—The azeotropic distillation of an aqueous acrylic acid solution was performed in the same manner as in Example 1. Distillation, except that a mixed solvent of propyl acrylate and heptane (blending ratio: 50; 50 weight ratio) was used as the azeotropic solvent. And the recirculation ratio is reduced to 1.08. The aqueous phase in line 8 contained 6.7% by weight of acetic acid and 1.5% by weight of acrylic acid at a stable operating time, that is, twice as much as the acrylic acid contained in the aqueous phase of Example 1. And the fluid extracted from the bottom of the azeotropic separation column 10 through line 15 contains 9 fi. 3% by weight of acrylic acid, (1.5% by weight of acetic acid, 0.01% by weight of solvent and 3.54% by weight). % By weight of other various ingredients. Therefore, the content of acetic acid is one-order higher than that of the product of Example 1, and the solvent content is 100 times that of Example 1. As above, the use of propyl acrylate containing 6 carbon atoms and When using a mixed solvent of heptane, acrylic acid of satisfactory quality cannot be obtained by a single distillation operation. Ο · 12% by weight of acetic acid,% of various other ingredients. Because (please read the precautions on the back before filling this page) .

、 1T 2 1- This paper size is applicable to China's National Advent (CNS) Ad Specification (210 × 297 mm) A7 B7 Printed by the Staff Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the Invention (-)-1 1 Real one. Basket 1 1 | Acrylic acid is recovered according to the steps described in λτΜ- Brother 2 figure 〇1 is obtained by gas phase catalytic oxidation of propylene using molecular oxygen-containing gas (air). The first gaseous mixture is guided to the acrylic acid collection tube column 2 0 1. Water contact and reading 1 Collection. The acrylic acid aqueous solution thus obtained is guided to the back of the propylene m release column 1 1 (not shown), where the acrolein contained in the solution is released. The rest of the water is noted. Contains 30% by weight of water and 3.0% by weight of acetic acid. For the solution item, add a sieve tray with 50 sheets each arranged at a regular interval of 147 mm, and fill in this pack. The distillation tube at the top of the column is in the center of the starting material supply tube page'— r 1 I is at the bottom of the bottom part -1. — azeotropic separation column 202 1 10 of the product extraction pipeline. As the azeotropic solvent, methyl methacrylate and the aqueous propylene 1 1 enoic acid solution were used. Boiling black distillation 0 The amount of the polymerization inhibitor to be used to vaporize the amount of acrylic acid vapor is 1 1 5 PP m: 1 butyldithioamine formate and 15 5) PP m of hydrogen. It is supplied to the top of the white column in the form of 1 dissolved in refluxing fluid. 1 I di i is 0.3 vol% of molecular oxygen vaporized to the bottom of the column. The amount of evaporated vapor represents the total volume of acs monoam vapor 1 I corresponding to the heat evaporating from the bottom of the commercial column, which is applied by the reboiler of the distillation M | column 1 0 azeotropic separation column 2 0 2The operating conditions during stable operation time are: tube 1 I temperature at the top of the column 4 5 ° C temperature at the bottom of the column 1 9 9 ° c pressure at the top of the column l · 1 force 16 mm affinity, reflux ratio (every t3t3 early time The reflux stream 131 »total moles of the body (1 total moles per distillate time), 1.2, and the aqueous i I acrylic solution is supplied via line 24 at 1 (1.2 liters / hour). As a result, azeotrope 1 1 1 2 2-1 i 1 1 (CNS) Λ4 specification (210X297 mm) A7 B7 Economic Lang Central Standards Bureau *: Printed by the Industrial and Consumer Cooperatives V. Invention Description (M)-1 1 'Separation column 2 0 2 The water phase obtained at the top contains 0.2 Acetic acid with 0.6% by weight and acrylic acid with 0.6% by weight. Acrylic acid extracted from the bottom of the column is 8 mm ^ 9 4.5% by weight 1 with acrylic acid N 2. 8% by weight with acetic acid and 2.7% by weight with various other components. '***, please first · »Contains solvents that do not exceed the solvent detection limit (1 PP Π1) 〇Read 1 I Perform azeotropic separation column 2 0 2 continuously for about 14 months under specified conditions 1 at 1 o'clock »Fixed and stable operating conditions are obtained. 0 Tube inspection is performed after the operation is stopped. Chapter 1 There is no sign of polymer formation when the inside of the column is 0. I I — — .. — — Example 7 Fill in this% An azeotropic distillation of an aqueous acrylic acid solution was performed in the same manner as in Example 6 '〆1 I distillation π 0 Q In addition to using n-butyl acetate as an azeotropic solvent and the reflux ratio is reduced to 1 1 1 U · The aqueous phase obtained from the top of the azeotropic separation column 2 0 2 at a stable operating time 1 I ordered 1.6% by weight Acetic acid and 1.0% by weight acrylic acid. The fluid extracted from the bottom of the column contained 9 4.4% by weight of acrylic acid 2.7% by weight of acetic acid 0.011% by weight of solvent and 2.9% by weight of other various components. Therefore, the residual solvent content is 100 times that of Example 6. 1 1 th Straight i ′ ′ azeotropic distillation of an aqueous acrylic acid solution in the same manner as in Example 6 1 I distilled off using ethyl methacrylate as an azeotropic solvent and the reflux ratio 1 1 was reduced to 0.58 〇1 I from The aqueous phase obtained at the top of the azeotropic separation column 2 0 2 contains 1 Cl I 1 1.2% by weight of acetic acid and 1-8% by weight of acrylic acid at a stable operating time. And the extracted stream SM W. from the bottom 1 of the column 9 4 .7% by weight of acrylic acid, 2.5% by weight of acetic acid, 1 I 2 r Ρ Τ solvents and 2.8% by weight of various other ingredients. Therefore, a total of 1 1 1 -2 3_ 1 1 1 1 This paper size is applicable to Chinese National Standard (CNS). Mit grid (210X297 mm) V. Description of the invention (") A7 B7 and acid ethyl intermediate are distilled and dissolved in the nozzle 2 ο 2 column The separation of boiling and mixing of tube separation means the method of using the law. The actual body of the instrument suddenly changes the amount of light without any method. The co-continuation of the boiling operation is determined in the olefin phase of the acidic acid, so that the propylene can pass through the column only to prevent the tube from turning off. In some cases, the agent that can be formed by boiling and fruiting can be dissolved. The dissolving tube of the Chinese and foreign agent column actually has 1 part. According to the tube, it is separated from the boiling point of the Chinese Communist Party, and its origin is-. In order to obtain pr B, αα solvent bottom dissolving column, the column of the mixed distillation and boiling co-centering is separated into a tube group and the solvent is separated and boiled together (in the top of the water-soluble, acid-acrylic acid ethylenic distilled water). Column-producing secondary tube. The natural acid is combined with steaming ethyl, such as distilling the two containing steam from the middle of the column through its column, the tube is also acidic, the propylene fraction propylene boiling degree is pure in the application of high solution The acid of the body acid is ethylene dipropylene-free, which is the highest quality. It is delivered to the material. The distilling acid agent that is produced according to the operation of the product is dissolved and boiled back to the common part, the bottom water column or the tube agent is self-dissolved and boiled. Gypsum combination refers to mixing with boiling water to distill it into the steaming section and the acid column and the second column of the tube section. (Please read the back first Please fill in this page before filling out this page) Install '11 Printed by the Central Bureau of Standards of the Ministry of Economic Affairs, Consumer Consumption Co., Ltd. Printed square pillars, tube, tube, tube, tube, tube, tube, tube, tube, tube, tube, etc. The acid-soluble acid of the crude acid agent borrowed from the distillate distillate is distillate, and the boiling distillate is left in the co-existence. The column method is used to separate the diacetate from the diacetate to the guide acid allyl. In one case, the degree can be reconstituted. According to the actual situation, the isomeric polymer can be acidic, and this olefin is rarely used in the middle. The degree of separation of propylene and propylene from the acid-acid pillarene tube to pure boiling is high. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 × 297 mm). Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs_ 38S0TI. Rev .; Γ! 7, invention description η 88. 9, i, complement j 1. diagrammatic illustration; Figure 1 is a flowchart of the first specific embodiment of the present invention, which is pseudo-distilled by a single distillation operation. High purity acrylic acid was obtained. Fig. 2 shows the process of the second embodiment of the present invention, which is awake, like obtaining high-purity acrylic acid through a double distillation operation. 2. Symbols of components 1 ~ 1 5 、 .2 1 ~ 3 6. • Flow line 10K 201. • Acrylic collection column 102 > 2 0 2- • Azeotropic separation column 103 λ 2 0 3 ·. • Solvent recovery Column 104 > 2 0 4 " • High azeotropic substance separation column 20, 40… Storage tank _24a- (Please read the precautions on the back before filling this page) The silver scale of the paper is applicable to the Chinese National Standard (CNS) A4 * Grid (21 OX297 mm)

Claims (1)

^ 86076 Announcement A8 B8 C8 D8 patent application scope. A gas phase collection solution for recovering acrylic acid or acrolein is separated from the column and azeotropic acrylic acid. At least one solvent of this method is methyl methacrylate, propylene oxide, vinyl propionate. A method of at least one solvent, methylcyclohexane, trimethyl-i, 3-penta: comprising contacting water with an acrylic acid-containing gas obtained during propylene and / or catalytic gasification, and acrylic acid, and the aqueous solution Distilled in the presence of an azeotropic solvent, and the isolation and recovery feature is the use of a mixed solvent containing A, which is selected from the group consisting of ethyl acrylate, methyl methyl propionate, allyl acetate, isopropyl acetate, and Methyl crotonate, and B, selected from the group consisting of toluene, heptane, 1-heptane cycloheptane, cycloheptadiene, cycloheptatriene, 2,4-diene, methylhexene, and methylene Cyclohexane (read the notes on the back first and then fill out this page) Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs as an azeotropic solvent. : 2 5 〇 as requested Lee range azeotropic separation of acrylic acid column top. A gas-liquid form of recycled acrylic acid. The method of claim 1, wherein the solvent A is at least one selected from the group consisting of an ester and methacryl methyl ester, and the solvent B is at least one selected from the group consisting of benzene and Gengyuan. The method of item 1 or item 2, wherein the blending ratio of solvent A ranges from 1 to 90% by weight. Or acrolein, a method for collecting water-soluble g, wherein the acetic acid is distilled from the bottom and the bottom is substantially free of B, which includes contacting water with acrylic acid-containing gas obtained during propylene and / or catalytic gasification, and acrylic acid, And the aqueous solution is introduced into azeotropic distillation-25 This paper is in accordance with Chinese National Standard (CNS) A4 specification (210 X 297 male bee) Λ8 S86076 D8 6. Application for patent scope distillation column and distillation in the presence of azeotropic solvent Isolation and recovery of acrylic acid by applying at least one solvent selected from the group consisting of ethyl acrylate, methyl methacrylate, vinyl acrylate, allyl acetate, isopropenyl acetate, vinyl propionate and methyl crotonic acid As an azeotropic solvent. 6. The method according to item 5 of the patent application, wherein the acrylic acid extracted from the azeotropic separation column is further purified in an acetic acid separation column. 7. The method described in item 5 or item 6 of the scope of patent application, wherein the azeotropic solvent is methyl methacrylate. ilf— ml tild nna 11 —m nflfl _ ml ml mt I ml "> (Please read the notes on the back before filling this page) Printed by the Staff Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economics-26- This paper size applies to China Standard (CNS) A4 size (210 X 297 mm)