• 专利附录
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  • 权利要求
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    • 专利摘要:

    公开号:SU963461A3
    申请号:SU782627502
    申请日:1978-06-14
    公开日:1982-09-30
    发明作者:Биола Жорж；Коморн Ив；Шнейдер Жерар
    申请人:Рон-Пуленк Эндюстри (Фирма)；
    IPC主号:
    专利说明:

    The invention relates to an improved process for the isolation of acrylic acid from its solutions in tri-n-butyl phosphate by distillation. It is known that the separation of acrylic acid from the reaction media of its manufacture, for example, from the crude product of the oxidation of propylene and / or acrolein, gives rise to complicated problems and that many methods have been proposed to solve them. Thus, a method of isolating acrylic acid is known by absorption in the gas phase or extraction in the liquid phase of acrylic acid using various solvents. Thereafter, acrylic acid is separated by distillation or is directly esterified in a recoverable medium 1. The closest in technical essence and the achieved effect is a method of separating acrylic acid from reaction mixtures by countercurrent extraction of acrylic acid with an extractant, followed by distillation of the target product. A mono- or dicarboxylic aliphatic or aromatic acid ester, tributyl phosphate or tricresyl phosphate 2 is used as the extractant. It has been established that tri-n-butyl phosphate is the best extractant from B1 listed above. However, there are numerous difficulties in the separation of acrylic acid from its solutions in this solvent. Thus, at high temperatures, especially in the presence of acids and / or water, tributyl phosphate is decomposed so that the extraction of acrylic acid from solution by distillation at normal or slightly reduced pressure leads to a significant loss of solvent. On the other hand, in order to obtain good performance in the steps of absorbing or recovering acrylic acid with tributyl phosphate, which is recycled to the distillation cycle, it is necessary that it have as low as 1-strilic acid as possible. In order to avoid decomposition of the solvent and to reduce its content in acrylic acid as much as possible, it would be possible to carry out distillation under high vacuum. However, in this case, it is difficult to produce acrylic acid because it has a relatively high crystallization point (ISfEC) corresponding to a vapor pressure of several millimeters of a mercury column. The purpose of the invention is to simplify the process of separation of acrylic acid 1z of its solution in tri-n-butyl phosphate. The aim is to achieve the separation of acrylic acid from its solution in tri-n-butyl phosphate by distillation, the process is carried out in an evaporator with a thin film at 119146 ° C and residual pressure, 2-9 mm Hg. Art. within 15–20 s, the vapor phase is condensed and the resulting condensate is subjected to double distillation at 120 ° С and 42 mm Hg, respectively. Art. and 130-142 ° C and 12-30 mm Hg, Art. and the concentration of acrylic acid to the bottom of the column is 19.822 wt.% for 20-30 minutes. The starting solution of acrylic acid in tri-n-butyl phosphate can be of any origin. It can be obtained, for example, by absorbing acrylic acid with tri-n-butyl phosphate, starting from a gas mixture resulting from the oxidation of propylene and / or acrolein. It can be obtained in the resultant of the extraction of aqueous solutions of acrylic acid with tri-n-butyl phosphate,. The concentration of acrylic acid in the original solution is insignificant, since the proposed method is equally applicable and equally beneficial in both concentrated and dilute solutions of acrylic acid / the initial solution can contain from 5 to 50% by weight of acrylic acid. In the first stage of the process, a vapor phase is obtained that contains practically all acrylic acid and part of the tri-n-butsphosphate by heating the initial liquid under conditions that do not decompose the three butyl phosphate. In this respect, the main factor is the upper temperature limit. It is not necessary to exceed 146 ° C, and the most preferable temperature range is Dy 119 and 146 ° C. The duration of the heating also has a certain value and must be controlled, the pull-out time is the lower the temperature is chosen, for the specified temperature range the holding time is between 15 and 20. The liquid remaining after the first Stage of the process. consists of tri-n-butylphosphate, practically devoid of acrylic acid and any other easily boiling organic acid, which could be present in the initial liquid. Obtaining an organic acid free tri-n-butyl phosphate after this first step is one of the important advantages of the method. Indeed, due to the rapid recovery of the target product, the solvent undergoes thermal action for a minimum time, as a result of which it practically does not decompose, moreover, since the tri-n-butyl phosphate does not contain acid, it can be directly used again for the extraction or absorption operations of acrylic acids from the reaction mixtures containing it. According to the second stage of the process, the vapor phase formed in the first stage is subjected, after partial or complete condensation, to distillation, allowing the collection of high purity acrylic acid. The temperature conditions of this distillation are critical: indeed, the boiling point of the liquid should not exceed the temperature at which the tributyl phosphate decomposes noticeably, i.e. approximately 142 ° C, and the most preferred operating range is between 120 and 140 ° C. This result cannot be achieved in the classical way by sufficiently reducing the pressure, since the acrylic acid crystallizes when the pressure in the column drops to a value less than 5 mm Hg. At the base of the column, an amount of acrylic acid is maintained which is at least sufficient so that distillation can be carried out under the desired temperature conditions. The amount of acrylic acid that should be maintained in solution is between 19.8 and 22 wt.%. As in the previous stage, the time of the Bi-hold acquires a definite value; it is the smaller, the higher the temperature. The pressure is regulated depending on the temperature and on the content of acrylic acid selected for each particular case. The liquid exiting at the bottom of the column, consisting of tri-n-butyl phosphate and some amount of acrylic acid, is preferably returned to the evaporation stage, which is the first stage of the proposed process. It is easy to understand the benefits of this return to the cycle, due to which, using the whole method, it is possible to select all the quantities of acrylic acid and regenerate the three-n-butyl phosphate contained in the initial solution. An embodiment of the process may furthermore consist in regulating the operation of the distillation column so that the liquid exiting at the bottom of the column and returned to the first stage has a concentration of the same order as the concentration of the initial solution. However, this method of implementation does not constitute HfcOM, and it is possible to work perfectly with the original and return solutions having different concentrations. The proposed method may contain a certain number of options that are applicable individually or simultaneously. According to the first variant, if the initial solution contains, along with acrylic acid, other low-boiling organic acids, in particular, acetic acid, then at an additional preliminary stage, the distillation of this acid is performed. The conditions of temperature and pressure should be close to these conditions during the distillation of acrylic acid, i.e. it is necessary to use such a temperature at the base of the column that does not lead to the decomposition of tributyl phosphate, and not to lower the pressure to the point at which the acetic acid freezes. Temperatures of the order of 120 to 150 ° C and pressures of from 30 to 100 mm of mercury are favorable working conditions. According to the second variant, which is particularly advantageous in the case when the method is applied to solutions having a relatively high concentration of acrylic acid, the whole or part of the treated solution is introduced at the outlet of the evaporator into the distillation column at the level where the concentration of acrylic acid is approximately equal to the concentration of the solution given. A part of the acrylic acid is distilled, and the liquid remaining at the base of the column is directed to the evaporator. At the same time, the working cycle as a whole remains unchanged. Polymerization inhibitors of known types, such as hydroquinone, hydroquinone methyl ester and others, can also be introduced into the cycle. The invention is illustrated in the drawing. The method is carried out as follows. The solution to be treated is fed through the channel 2 into the evaporator 1. From the bottom of the device 1, tri-n-butyl phosphate, freed from acrylic acid and from any other possible acid, is removed and sent along line 3 to the absorption or extraction stage of acrylic acid, i.e. used to prepare the stock solution. The vapor phase, containing acrylic acid and possibly low-boiling acids such as acetic acid, and some tri-n-butyl phosphate, is removed through channel 4 from apparatus 1, then, after partial and / or complete condensation, is introduced into column 5 where the acetic acid passes into the head and is discharged through line 6. The remaining liquid phase flows through channel 7 and is fed to the distillation column 8, where the acrylic acid leaves through head 9, while the liquid taken from the bottom of the column returns to channel 10 to the input device va. Column 5 is optional and is eliminated if the feed solution does not contain acids other than acrylic acid. The proposed method can be carried out continuously or periodically. Example 1. In the evaporator with a thin film 1 is fed through the pipe 2 108,78 weight.h. mixtures containing 6.52% by weight of acrylic acid, 93.30% of tributyl phosphate, 0.01% of water and 0.17% of acetic acid. The evaporator 1 is supported using an appropriate system under a pressure of 5 mm Hg and at 128 ° C. There is a separation of the liquid fraction and vaporous fraction. The liquid fraction taken through the nozzle 3 at the bottom of the apparatus is 76.77 parts, containing 0.1% by weight of acrylic acid and 99.9% of tributyl phosphate. This liquid, after appropriate cooling, is sent back to the acrylic acid extractor. The vaporous fraction through the channel 4 after condensation is sent to the distillation column 5. It comprises 32.01 parts by weight containing 21.90% by weight of acrylic acid, 77.46% of tributyl phosphate, 0.59% of vinegar-. hydrochloric acid and 0.03% water. Column 5 operates at a pressure of 35 mm Hg at the head and 42 mm: Hg at the base, which corresponds to temperatures of 40 ° C and 120 ° C, respectively. The presence of tributyl phosphate allows the separation in the head after 60.19 parts by weight. waste containing 89.47% by weight of acetic acid, 5.26% acrylic acid and 5.26% water. The liquid exiting at the bottom of the column through channel 1 is 31.82 parts by weight, containing 77.94% tributyl phosphate, 22.00% acrylic acid and 0.06% acetic acid. This product is sent to a column 8 operating under a pressure of 10 mm Hg at a head of i 12 mm at the base. Temperatures are respectively 40 and 130 ° C. The fraction of the head 9 is 5.7 parts by weight. corresponds to the production of acrylic acid with a purity of 99.65%. Waste flowing through channel 10, consisting of 26.12 parts of a liquid containing 94.95% of tributyl phosphate and 5.06% of acrylic acid, is returned to the inlet of the apparatus 1. Example 2. I submit 128 to thin-film evaporator 1 , 17 weight. including a solution of tributyl phosphate containing 1.19% by weight of acrylic acid. The evaporator 1 is maintained under a pressure of 9 mm Hg and at 146 ° C. As a result of separation, two fractions are obtained: the liquid fraction and the vapor fraction. The residence time of the medium in the evaporator is 20 seconds. The liquid fraction is discharged through the cuttings 3 at the bottom of the device: it represents 8.2.68 parts of three butyl phosphate containing 0.26 wt. acrylic acid and 99.74 wt.% three tilphosphate. After appropriate cooling, this liquid is sent to an acrylic acid separation device. Steam fraction through t; pipe 4 is condensed and sent to distillation column 5. This fraction is 45.49 pts in weight, containing 2.85% acrylic acid and 97.1-5% tributyl phosphate. This product is sent to column 8, which operates under a pressure of 5 mm of mercury column in the head section of the column and 7 mm of mercury column in the lower part. The temperatures in these parts of the column are respectively 42 ° C and 149 ° C. The residence time of the medium in column 8 is 20 minutes. The fraction from the bottom of the column 9 of 1.21 weight, corresponds to the production of acrylic acid with a frequency of 99.8%. Flowing through the nozzle 10 medium contains 44.28 parts of a liquid containing 99.8% tri-butyl phosphate and 0.2 acrylic acid. This effluent liquid is recirculated to power the device 1.. Example 3. In the thin-film evaporator 1 is fed through the pipe 2 106,52 weight.h. tributyl phosphate solution containing 13.6% by weight of ACRYLIC acid and 0.5% by weight of acetic acid, as well as 500 parts per thousand of hydroquinone methyl ester (polymerization inhibitor). In the evaporator 1, the pressure is maintained at -2 mm Hg at 119 ° C. As a result of the separation process, neither liquid nor vapor fractions are obtained. The residence time of the medium in the evaporator is 15 seconds. The liquid fraction removed through pipe 3 is 66.99.h. a solution of 0.71 wt.% acrylic acid in tributyl phosphate. After cooling, this liquid is directly injected into an apparatus for extracting acrylic acid. The vapor fraction passing through the pipe 4 is condensed and sent to the distillation column 5. The condensate is 39.61 parts by weight. a solution of 35.43% by weight of acrylic acid, 1.30% by weight of acetic acid, 63.15% by weight of tributyl phosphate and. 1 0.12% by weight of oxen. The distillation column 5 operates under a pressure of 40 mm Hg at the head and 47 mm Hg at the bottom, with temperatures of 40 ° C and 137 s respectively maintained in these parts of the column. Time of stay in the distillate. Station column 5 is 30 minutes. The presence of tributyl phosphate allows the separation of the medium at the head of the column using conduit 6 of 0.57 parts by weight. effluent containing .89.47 wt.% acetic acid together with 8.05 wt.% acrylic acid and 8 wt.% water. The liquid leaving the bottom of the column through the pipe 7 is 39.04 parts by weight, containing 64.11% by weight,% of tributyl phosphate, 35.83% by weight of acrylic acid and 0.05% by weight of acetic acid. This product is sent to column 8, which operates under a pressure of 10 mm Hg at the head and 11 mm Hg at the bottom of the column. In these parts of the column, respectively, the temperature is maintained at 40 ° C and 143 s. The residence time of the medium in column 8 is 30 minutes. Fractions from the head of the column 9 out of 10.07 weight.h. corresponds to the production of acrylic acid with a purity of 99.8%. Through the nozzle 10, a liquid consisting of 28.97 parts by weight flows out. a liquid containing 84.4% by weight of tributyl phosphate and 13.6% by weight of acrylic acid, this liquid is recycled to power the device 1. Example 4. A thin film evaporator 1 is fed through the nozzle 2 of 170.12 parts by weight. tributyl phosphate solution containing 5.24% by weight of acrylic acid and 0.35% by weight of acetic acid. In the evaporator 1 maintain a pressure of 5 mm Hg and a temperature of 143 ° C. In the evaporator, the solution is divided into a liquid fraction and a vapor fraction. The evaporation time in the evaporator is 15 seconds. Removing through the pipe 3, the liquid fraction is 128.1 parts by weight. a solution of 0.64% by weight of acrylic acid in tributyl phosphate. After cooling, this liquid is directed
    to an acrylic acid recovery device.
    The fraction exiting through the nozzle 4 is condensed and sent to the distillation column 5. It is 42.02 parts by weight. solution of 19.24 wt.% acrylic acid, 1.12 wt.% acetic acid, 79.54 wt.% tributyl phosphate and 0.1 wt.% water.
    The distillation column 5 operates under a pressure of 40 mm Hg in the head section and 47 mm Hg in the lower part of the column, this pressure corresponding to a temperature of 40 ° C and 128 ° C.
    The residence time of the working medium in column 5 is 45 minutes.
    The presence of tributyl phosphate allows separation by conduit 6 at the head of a column of 0.50 parts by weight. hsdkostyu containing 89.1 wt.% acetic acid with 2.8 wt.% acrylic kg slots and 8.1 wt.% water. The liquid exiting through the tube 7 from the bottom of the column is 41.52 parts by weight, containing 19.44% by weight of acrylic acid, 80.50% by weight of tributyl phosphate and 0.06% by weight of acetic acid.
    This product is sent to column 8, which operates under a pressure of 30 mm Hg at its head and 32 mm Hg at the bottom. In these parts of the distillation column, respectively, the temperature is maintained at 25 ° C and 142 ° C. The residence time of the medium in column 8 is 30 minutes.
    Head fraction 9 of 4.32 weight.h.
    corresponds to the production of acrylic acid with a purity of 99.7%. The liquid flowing out through the pipe 10 is 37.20 parts by weight. liquid containing 10.1 wt.% acrylic
    acids and 89.9% by weight of tributyl phosphate.
    权利要求:
    Claims (2)
    [1]
    1.Patent of France. 1452566, class C 07 C, publ. 1965.
    [2]
    2. The patent of France No. 1558432, cl. C 07 C, publ. 1967.
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    同族专利:
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    CA1103196A|1981-06-16|
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    DE2862438D1|1984-10-04|
    JPS5416421A|1979-02-07|
    EP0000110A1|1978-12-20|
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    EP0000110B1|1984-08-29|
    FR2394512B1|1980-01-18|
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    IT7849856D0|1978-06-13|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3092587A|1959-07-22|1963-06-04|Bergwerksgesellschaft Hibernia|Process for the production of high percentage solutions of organic peroxides|
    FR1359885A|1963-03-21|1964-04-30|Electrochimie Soc|Manufacturing process of glacial acrylic acid|
    US3555082A|1966-12-15|1971-01-12|Knapsack Ag|Process for isolating acrylic acid from the reaction gases obtained by oxidation of propylene or acrolein|
    AT274743B|1967-09-28|1969-09-25|Krems Chemie Gmbh|Process and device for the continuous fractionation of tall oil or other organic multicomponent mixtures|
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    NL180579C|1972-05-24|1987-03-16|Sumitomo Chemical Co|METHOD FOR SEPARATING A MIX consisting of ACRYLIC ACID, ACETIC ACID AND WATER.|
    US4043873A|1973-06-15|1977-08-23|Societa' Italiana Resine S.I.R. S.P.A.|Plural stage recovery of trioxane in a process having a molecular distillation step|JPS6098794A|1983-11-04|1985-06-01|Matsushita Electric Ind Co Ltd|Piezo-electric electroacoustic transducer|
    JPS61159899A|1985-01-08|1986-07-19|Kimio Takahashi|Piezoelectric speaker|
    JPS61159900A|1985-01-08|1986-07-19|Kimio Takahashi|Piezoelectric speaker|
    JPS61161100A|1985-01-09|1986-07-21|Kimio Takahashi|Piezoelectric speaker|
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    JPH01176200A|1987-12-29|1989-07-12|Nec Corp|Piezoelectric diaphragm|
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    DE19740252A1|1997-09-12|1999-03-18|Basf Ag|A novel method of acrylic and methacrylic acid production by catalytic gas oxidation of 3 - 4C hydrocarbons|
    DE19833049A1|1998-07-22|2000-01-27|Basf Ag|Acrylic acid production by gas-phase oxidation of 3C feedstock, involves work-up by condensation and vacuum-crystallization, recycling mother liquor and evaporated liquid to the condensation stage|
    DE19838783A1|1998-08-26|2000-03-02|Basf Ag|Process for the continuous production ofacrylic acid|
    NL1013682C2|1999-11-26|2001-05-30|Purac Biochem Bv|Method and device for purifying an aqueous solution of lactic acid.|
    US20030150705A1|2002-01-08|2003-08-14|Deshpande Sanjeev D.|Acrylic acid recovery utilizing ethyl acrylate and selected co-solvents|
    DE10220494A1|2002-05-07|2003-11-20|Basf Ag|Process for the preparation of an aqueous alkali acrylate solution|
    TWI337996B|2003-10-09|2011-03-01|Basf Ag|Rectificative separation of an acrylic acid-containing liquid|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    FR7718136A|FR2394512B1|1977-06-14|1977-06-14|
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