Production method of isobutyl acrylate
阅读说明：本技术 一种丙烯酸异丁酯的生产方法 (Production method of isobutyl acrylate ) 是由 于彦哲 于 2019-11-05 设计创作，主要内容包括：本发明公开一种丙烯酸异丁酯的生产方法,包括如下内容：以丙烯酸、异丁醇为反应原料,在和催化剂以及阻聚剂混合后,利用反应精馏的生产工艺,获得丙烯酸异丁酯粗品,粗品再经过萃取、碱洗和连续精馏后得到目标产物丙烯酸异丁酯。本发明实现了异丁醇等原料的回收利用,反应条件温和,污水排放少,CODCr低；丙烯酸和异丁醇等原料利用率高,总转化率>99.5％,最终产品的选择性>98％；根据不同的应用需求,可以选择不同工艺段,生产出两种级别的丙烯酸异丁酯：(1)合格品：丙烯酸0.4％,丙烯酸异丁酯≥99.5％；(2)优级品：丙烯酸异丁酯≥99.9％。(The invention discloses a method for producing isobutyl acrylate, which comprises the following steps: acrylic acid and isobutanol are used as reaction raw materials, mixed with a catalyst and a polymerization inhibitor, and then subjected to reactive distillation to obtain a crude product of isobutyl acrylate, and the crude product is subjected to extraction, alkali washing and continuous rectification to obtain a target product of isobutyl acrylate. The invention realizes the recycling of raw materials such as isobutanol, has mild reaction conditions, less sewage discharge and low CODCr; the raw materials such as acrylic acid, isobutanol and the like have high utilization rate, the total conversion rate is more than 99.5 percent, and the selectivity of the final product is more than 98 percent; according to different application requirements, different process sections can be selected to produce two grades of isobutyl acrylate: (1) qualified products: 0.4 percent of acrylic acid and more than or equal to 99.5 percent of isobutyl acrylate; (2) the superior products are as follows: isobutyl acrylate is greater than or equal to 99.9%.)
1. A method for producing isobutyl acrylate is characterized by comprising the following steps: taking acrylic acid and isobutanol as reaction raw materials, and adding the raw materials in a molar ratio of 1: 1.0-1.1, adding a catalyst and a polymerization inhibitor, wherein the addition amount of the catalyst accounts for 0.25-5% of the total material amount, the addition amount of the polymerization inhibitor accounts for 0.03-0.3% of the total material amount, obtaining an isobutyl acrylate crude product by using a reactive distillation system, and extracting, alkali washing and continuously rectifying the isobutyl acrylate crude product to obtain a target product isobutyl acrylate.
2. The method for producing isobutyl acrylate according to claim 1, wherein the catalyst is one or more of benzenesulfonic acid, toluenesulfonic acid, sulfonic acid resin or sulfuric acid; the polymerization inhibitor is one or more of diethylhydroxylamine, p-hydroxyanisole, hydroquinone, phenothiazine or 2, 6-di-tert-butyl-p-cresol.
3. The method for producing isobutyl acrylate according to claim 1, wherein the reaction temperature of the reaction kettle of the reactive distillation system is between 80 and 110 ℃, the pressure is between 30 and 100kpa, the reaction time is between 8 and 24 hours, during which the distillate of the distillation column of the reactive distillation system is condensed and then enters an oil-water separation tank, the temperature is controlled below 45 ℃, after the mixture of the distilled isobutyl acrylate, water and isobutanol is layered, the oil phase rich in isobutyl acrylate at the upper layer flows back to the reactive distillation system, and the water phase is extracted and enters an intermediate storage tank for later use.
4. The method for producing isobutyl acrylate according to claim 3, wherein the reaction is stopped when the acrylic acid content of the reaction kettle of the reactive distillation system is reduced to below 0.5% and the isobutanol content of the reaction kettle is reduced to below 5.0%, and the reaction kettle is pumped into a middle storage tank of the reaction kettle for further purification.
5. The method for producing isobutyl acrylate according to claim 1, wherein the recovery of the catalyst is achieved by batch multi-stage extraction or continuous tower extraction by using a water phase extraction process, the content of the catalyst discharged from the oil phase is controlled below 500ppm, the oil phase enters a feeding intermediate storage tank of a reactive distillation system, the water phase containing the catalyst enters a catalyst distillation water removal system, the concentrated catalyst returns to the reactive distillation system for reuse, and the distilled water is treated in an alcohol water recovery tower; when the catalyst is sulfuric acid, extraction is not needed, and alkali washing neutralization is directly carried out; when the catalyst is sulfonic acid resin, the reaction material is directly filtered, and an extraction section is omitted.
6. The method for producing isobutyl acrylate according to claim 3, wherein before entering the reactive rectification system, the oil phase rich in isobutyl acrylate is subjected to alkali washing according to needs or directly enters the reactive rectification system, and when the oil phase is rectified after an alkali washing section is selected, the purity of isobutyl acrylate can reach more than 99.9%; when alkali washing section is not selected, the product containing 99.5% of isobutyl acrylate and 0.4% of acrylic acid is obtained by direct rectification.
7. The method for producing isobutyl acrylate according to claim 3, wherein the rectification column of the reactive rectification system is divided into a light component removal column and a heavy component removal column, and the rectification operation is performed by adopting a continuous rectification mode; when the temperature of the bottom of the light component removal tower is 80-110 ℃, the pressure is 10-50kpa, and the content of isobutanol at the bottom of the tower is less than or equal to 0.03%, extracting materials at the bottom of the tower, pumping the materials into a heavy component removal tower, and feeding the extracted materials at the top of the tower into an alcohol-water recovery tower; the temperature of the de-heavy tower is 100-.
8. The method for producing isobutyl acrylate according to claim 1, wherein the raw material source of the alcohol-water recovery column for recovering isobutanol is: (a) water is distilled out of the reaction rectification system; (b) distilled water of the catalyst distillation water removal system; (c) tower top material of a light component removing tower of the reactive distillation system; the alcohol recovery tower is a normal pressure tower, the temperature of the tower bottom is maintained between 90 ℃ and 105 ℃, a cooling and oil-water separation system similar to the tower top of the reactive distillation device is arranged at the tower top, the reflux of the tower top is separated water phase, the separated oil phase is mainly isobutanol, and the wastewater with CODCr <3000 is extracted from the tower bottom of the alcohol recovery tower.
9. The method for producing isobutyl acrylate according to claim 7, wherein the heavy component with isobutyl acrylate content less than 35% is obtained from the bottom of the de-heavy column, acrylic acid and isobutanol are recovered by an additional high-temperature cracking device, or the product is sold as high-energy liquid fuel; when the high-temperature cracking device is used for recovering the raw materials, the temperature of the high-temperature cracking device is controlled at 160-200 ℃, a copper salt polymerization inhibitor is added, cracking is carried out under normal pressure, and the cracked materials are returned to the previous reaction rectifying system for recycling.
Technical Field
The invention relates to a method for producing isobutyl acrylate (i-BA).
Background
The acrylic coating has the characteristics of light color, excellent weather resistance, multiple varieties, wide application, environmental protection and the like, so that the acrylic coating not only has wide range and large quantity, but also presents a favorable situation of rapid development along with rapid development and application of the coatings in the automobile industry, the building industry, the household appliance industry and other industries. In order to meet the objective requirements of acrylic paint development, the performance of acrylic resins used in combination with acrylic paints and determining the performance of acrylic paints must be improved in various aspects to meet and meet the requirements and developments of different paints.
The acrylic resin for the coating belongs to a high polymer, and the molecular movement of the acrylic resin comprises chain segment movement and whole molecular chain movement, namely the elasticity of solid and the viscoelasticity of liquid are reflected. Glass transition temperature (T) g) The lowest temperature of the polymer chain segment which can move is directly related to the flexibility of the molecular chain, and the higher the flexibility of the molecular chain is, the lower the glass transition temperature is; the molecular chain has high rigidity and the glass transition temperature is high. Since a coating film is softened at a temperature higher than the glass transition temperature of a coated product, the coated product is generally used at a temperature lower than the glass transition temperature, and therefore, it is desired that the glass transition temperature is higher in use. T of acrylic resin gThe higher the value, the harder the coating film and the stronger the scratch resistance; t is gThe lower the value, the lower the hardness of the coating film, the poorer the scratch resistance, and the coating film tends to become soft, sticky and easily contaminated at higher temperatures in summer. T of acrylic resin gThe higher the paint making, the better the film drying rate; t is gThe lower the drying rate after the resin varnish is made, the worse. T of acrylic resin gThe higher the solvent release of the coating, the better; the lower the solvent release, the worse. In general, under the same synthesis conditions, the acrylic resin T gThe higher the value is, the better the solvent resistance and corrosion resistance of the coating film after the paint is prepared; resin T gThe lower the value, the lower the corrosion resistance and solvent resistance of the coating film after painting. T of acrylic resin gDepending on the monomers and formulation used, the glass transition temperature (T) of the acrylic resin is determined once the overall requirements are met, depending on the type, properties and specific properties of the coating g) The glass transition temperature of the acrylic resin is determined by the T of the monomers in the formulation gDetermined, difference of height T gThe target T can be obtained only by using the monomers in a composite way gThe acrylic resin of (1). Common monomer for acrylic resin and glass transition temperature (T) thereof g) See attached table 1.
Attached table 1: monomers commonly used for acrylic resins and glass transition temperatures (T) thereof g)
Such as one-component thermoplastic acrylic coatings, T of acrylic resins thereof
gResin T for plastic coating as primer at 100-110 deg.C
gThe temperature can be controlled at 45-60 ℃. T of resin for thermoplastic acrylic metallic paint or semi-gloss or matt paint for finishing paint of TV set, mobile phone, computer, etc
gT of thermoplastic acrylic resin modified by PP and other plastic primers at 90-110 DEG C
gPreferably 50-65 ℃. And the most used architectural coating industry, T of its emulsion
gGenerally, the building coating emulsion market demand of China is about 150 ten thousand tons per year at the temperature of 10-30 ℃, and partial waterproof emulsion and partial special emulsion are not included. To avoid the use of the more expensive methyl methacrylate MMA, the current Chinese architectural coating emulsions are largely made of styrene (T) with a high
In pure acrylic emulsion in the coating emulsion, the polymerization monomer is generally compounded by methyl methacrylate MMA, n-butyl acrylate (n-BA) and isooctyl acrylate (2-EHA) to prepare the proper T gThe target emulsion of (1). Wherein 2-EHA is mainly used for increasing the hydrophobicity and the water resistance of the emulsion and is matched with MMA and n-BA to regulate the T of the product g. This combination necessitates the use of large amounts of MMA to convert the T of the acrylic emulsion to a pure acrylic emulsion gThe temperature is increased to 10-30 ℃. However, MMA is not good enough in weather resistance and water resistance, and excessive addition of MMA lowers the overall performance of the product, so that the choice of mainstream products is not given. We have found that: acrylic acid isobutyl ester (T) g259K, -14 ℃ C. has a T which is higher than that of n-BA and 2-EHA gAnd alsoThe acrylic emulsion has better comprehensive performance, can reduce the using amount of MMA with higher price when being used in the pure acrylic emulsion for building and coating, can improve multiple performance indexes of yellowing resistance, water resistance and the like of the emulsion and building coating, and can reduce the cost. In addition, according to the characteristics of the special molecular structure of the isobutyl acrylate (i-BA), the isobutyl acrylate and MMA are mixed and used in polymethyl methacrylate (PMMA), and the impact resistance of the PMMA is also remarkably improved.
Because of the existence of simple substitutes, the production process of isobutyl acrylate is more complicated than the production processes of n-butyl acrylate (n-BA) and isooctyl acrylate (2-EHA) which are substitutes, and China has no industrial production device of isobutyl acrylate (i-BA) so far. The patent related to isobutyl acrylate is not found, and even related documents are only found in an article of researches on reaction conditions and kinetics of acrylic acid and isobutyl alcohol synthesized acrylic acid isobutyl acetate by researchers such as Song dynasty people and Wang Hongfeng reported by Beijing chemical fiber academy of Industrial science in 1986, the researches utilize the reaction kinetics researches of sulfuric acid and P2O5 as catalysts, the reaction conditions are not optimized, and the comprehensive consideration of material recycling, equipment corrosion and pollution is very lacking, so the research result of the article is far away from the real industrial production. Other articles on the separation of mixtures of isobutyl acrylate, isobutanol and water have proved that the data are too much different from each other by our experiments, and are not cited here.
Disclosure of Invention
In order to solve the above situation, the invention provides a method for producing isobutyl acrylate (i-BA), which takes acrylic acid and isobutanol as reaction raw materials, and obtains the target product isobutyl acrylate through the production processes of process sections such as reactive distillation, extraction, alkali washing, continuous distillation, material recovery and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
a process for the production of isobutyl acrylate comprising: taking acrylic acid and isobutanol as reaction raw materials, and adding the raw materials in a molar ratio of 1: 1.0-1.1, adding a catalyst and a polymerization inhibitor, wherein the addition amount of the catalyst accounts for 0.25-5% of the total material amount, the addition amount of the polymerization inhibitor accounts for 0.03-0.3% of the total material amount, obtaining an isobutyl acrylate crude product by using a reactive distillation system, and extracting, alkali washing and continuously rectifying the isobutyl acrylate crude product to obtain a target product isobutyl acrylate.
Further, the catalyst is one or more of benzene sulfonic acid, methyl benzene sulfonic acid, sulfonic acid resin or sulfuric acid; the polymerization inhibitor is one or more of diethylhydroxylamine, p-hydroxyanisole, hydroquinone, phenothiazine or 2, 6-di-tert-butyl-p-cresol.
Further, the reaction temperature of a reaction kettle of the reactive distillation system is between 80 and 110 ℃, the pressure is between 30 and 100kpa, and the reaction time is between 8 and 24 hours, wherein a distillate of a distillation tower of the reactive distillation system is condensed and then enters an oil-water separation tank, the temperature of the oil-water separation tank is controlled to be below 45 ℃, after a mixture of the distilled isobutyl acrylate, water and isobutanol is layered, an oil phase rich in the isobutyl acrylate on the upper layer reflows to the reactive distillation system, and a water phase is extracted and then enters an intermediate storage tank for later use.
Further, when the content of acrylic acid in the kettle liquid of the reaction kettle reaction of the reactive distillation system is reduced to be below 0.5 percent and the content of isobutanol is reduced to be below 5.0 percent, the reaction is stopped, and the reaction kettle liquid is pumped into a middle storage tank of the reaction kettle liquid for later use and is further purified.
Furthermore, the recovery of the catalyst is realized by adopting a water phase extraction process through intermittent multi-stage extraction or continuous tower extraction, the catalyst content of the discharged oil phase is controlled below 500ppm, the oil phase enters a feeding intermediate storage tank of a reaction rectification system, the water phase containing the catalyst enters a catalyst distillation water removal system, the concentrated catalyst returns to the reaction rectification system for reuse, and the distilled water is treated in an alcohol water recovery tower; when the catalyst is sulfuric acid, extraction is not needed, and alkali washing neutralization is directly carried out; when the catalyst is sulfonic acid resin, the reaction material is directly filtered, and an extraction section is omitted.
Further, before the oil phase rich in isobutyl acrylate enters a reactive rectification system, alkali washing is selected according to needs or the oil phase directly enters the reactive rectification system, and when an alkali washing working section is selected and then rectified, the purity of isobutyl acrylate can reach more than 99.9%; when alkali washing section is not selected, the product containing 99.5% of isobutyl acrylate and 0.4% of acrylic acid is obtained by direct rectification.
Further, a rectifying tower of the reactive rectifying system is divided into a light component removing tower and a heavy component removing tower, and a continuous rectifying mode is adopted for rectifying operation; when the temperature of the bottom of the light component removal tower is 80-110 ℃, the pressure is 10-50kpa, and the content of isobutanol at the bottom of the tower is less than or equal to 0.03%, extracting materials at the bottom of the tower, pumping the materials into a heavy component removal tower, and feeding the extracted materials at the top of the tower into an alcohol-water recovery tower; the temperature of the de-heavy tower is 100-.
Further, the raw material sources of the alcohol-water recovery tower for recovering isobutanol are as follows: (a) water is distilled out of the reaction rectification system; (b) distilled water of the catalyst distillation water removal system; (c) tower top material of a light component removing tower of the reactive distillation system; the alcohol recovery tower is a normal pressure tower, the temperature of the tower bottom is maintained between 90 ℃ and 105 ℃, a cooling and oil-water separation system similar to the tower top of the reactive distillation device is arranged at the tower top, the reflux of the tower top is separated water phase, the separated oil phase is mainly isobutanol, and the wastewater with CODCr <3000 is extracted from the tower bottom of the alcohol recovery tower.
Further, heavy components with isobutyl acrylate content less than 35% are extracted from the bottom of the de-heavy tower, and acrylic acid and isobutyl alcohol are recovered through an additional high-temperature cracking device or sold as high-energy liquid fuel; when the high-temperature cracking device is used for recovering the raw materials, the temperature of the high-temperature cracking device is controlled at 160-200 ℃, a copper salt polymerization inhibitor is added, cracking is carried out under normal pressure, and the cracked materials are returned to the previous reaction rectifying system for recycling.
Has the advantages that:
1. the production method of the invention has sufficient raw materials and low production cost: one of main raw materials used in the invention is acrylic acid which is a bulk chemical with rich sources, the yield of China is more than 200 ten thousand tons/year, the yield of the whole world is more than 600 ten thousand tons/year, the resources are rich, and the price is stable; the other main raw material used in the invention is isobutanol which is a byproduct of n-butanol, the annual output in 2018 across the country is about 12 ten thousand tons, and the price of the isobutanol serving as the byproduct is about 700 yuan lower than that of the n-butanol per ton.
2. Acrylic acid isobutyl ester (T) g259K and 14 ℃ has higher glass transition temperature relative to n-BA and 2-EHA and better comprehensive performance, and when the acrylic emulsion is used in the pure acrylic emulsion for building and coating, the acrylic emulsion not only can reduce the using amount of MMA with higher price, but also can reduce the production cost, bring direct economic benefit, improve the comprehensive performance of terminal products and increase the competitiveness of related products.
3. The production method for producing isobutyl acrylate provided by the invention fully combines the kinetic characteristics of reaction and the rectification characteristics of physical properties, elaborately designs the reaction temperature and the rectification conditions, and realizes the optimal matching of the reactive rectification section by utilizing the azeotropic-cooling layering characteristics of materials; the invention also realizes the recovery of the liquid-separating water phase, the catalyst concentration and concentration distilled water and the isobutanol of the light-component removing tower by using the same principle, improves the yield, simultaneously achieves the recovery and the utilization of the raw materials, reduces the organic matter content of the waste water and reduces the treatment difficulty of the production waste water; the invention provides a production method for extracting the catalyst, which can realize the recycling of the catalyst, not only can reduce the production cost, but also can ensure that the production method has the flexibility of catalyst selection, not only can select the (methyl) benzenesulfonic acid catalyst, reduce the equipment investment cost and avoid the difficulty in sewage treatment caused by alkaline washing, but also can select the cheap sulfuric acid as the catalyst to carry out the alkaline washing later and reduce the cost and the production investment.
4. The production method for producing isobutyl acrylate provided by the invention can add alkaline washing equipment before the rectification of the crude product, so that the process route can select cheap sulfuric acid as a catalyst, and can select different processes according to specific consumption requirements, and finally can produce two grades of isobutyl acrylate: (a) qualified products: isobutyl acrylate > 99.5%, acrylic acid 0.4%; (b) the superior products are as follows: isobutyl acrylate > 99.9%.
Drawings
FIG. 1 is a schematic diagram of the process for producing isobutyl acrylate according to the present invention;
FIG. 2 is a graph of conversion over time for example 1 of the present invention;
FIG. 3 is a simulated diagram of activation energy of esterification reaction according to example 1 of the present invention;
FIG. 4 is a diagram showing the ternary phase equilibrium of isobutyl acrylate-isobutanol-water in example 2 of the present invention;
FIG. 5 is a simulated graph of the reverse reaction kinetics of I-BA of example 3 of the present invention;
FIG. 6 is a graph of a PTSA concentration index simulation of example 4 of the present invention;
FIG. 7 is a graph of sulfuric acid concentration index simulation of example 4 of the present invention.
Detailed Description
The invention discloses a method for producing isobutyl acrylate (i-BA), which comprises the following steps:
as shown in figure 1, after uniformly mixing a reactant acrylic acid, an isobutanol catalyst and a polymerization inhibitor (including recovered alkyd or catalyst) (MIX-1), carrying out a reaction in a reaction kettle (REACTOR) of a reactive distillation system at a reaction temperature of 85-115 ℃ and a pressure of 30-100kpa for 8-24 hours; wherein isobutyl acrylate, water and raw material isobutanol produced by the reaction are evaporated by using a rectifying tower (DISTIL-1) of a reactive rectifying device; condensing (COOLER) a mixture of the three materials, then feeding the mixture into a water-oil separation tank (SEP-1), refluxing an oil phase on the upper layer back to the reaction rectification system, and extracting a water phase and then feeding the water phase into an intermediate storage tank; stopping the reaction until the content of acrylic acid in the reaction kettle liquid is reduced to be below 0.5 percent and the content of isobutanol is reduced to be below 5.0 percent, and pumping the reaction kettle liquid into a reaction liquid intermediate storage tank. The recovery of the catalyst in the reaction kettle liquid adopts a water phase extraction process, can be realized by intermittent multi-stage extraction or continuous tower Extraction (EXTRACT), when the content of the catalyst discharged from the oil phase is required to be below 500ppm, the oil phase enters a feeding intermediate storage TANK (TANK2) of a rectification system, the water phase containing the catalyst enters a catalyst distillation water removal system (CONCENTR), and the concentrated catalyst returns to the reaction rectification system for recycling.
Before the oil phase rich in isobutyl acrylate enters a reactive rectification system, alkali washing (NEUTRAL) can be selected according to requirements or the oil phase directly enters a rectification system comprising a light component removal tower (DISTIL-3) and a heavy component removal tower (DISTIL-4). After the secondary rectification of the alkali washing section, the purity of the isobutyl acrylate can reach more than 99.9 percent; without the selection of a caustic washing section, a product containing > 99.5% isobutyl acrylate and about 0.4% acrylic acid can be obtained. The rectifying tower is divided into a light component removing tower and a heavy component removing tower, and the rectifying operation is carried out by adopting a continuous rectifying mode; the bottom temperature of the light component removal tower is maintained at 80-110 ℃, the pressure is 10-50kpa, the content of isobutanol at the bottom of the tower is less than or equal to 0.03%, and materials at the bottom of the tower are pumped into a heavy component removal tower after being extracted; the temperature at the bottom of the de-heavy tower is maintained at 120 ℃ of 100-. The heavy components at the bottom of the tower can be used for recovering acrylic acid and isobutanol by an additional high-temperature cracking device and can also be sold as high-energy liquid fuel.
Extracting residual alcohol-containing water, alcohol-containing water distilled by a catalyst distillation water removal system (CONCENTR) and alcohol-water mixture distilled by a light component removal system (DISTIL-3) after the water-oil separation tank (SEP-1) is discharged, and feeding the alcohol-water mixture into an alcohol recovery tower (DISTIL-2) to realize the recovery of isobutanol and ester. The alcohol recovery tower (DISTIL-2) is an atmospheric tower, the temperature of the tower bottom is maintained between 90 ℃ and 105 ℃, a cooling and oil-water separation system similar to a rectifying tower (DISTIL-1) of a reactive rectifying device is arranged at the tower top, the reflux of the tower top is separated water phase, the separated oil phase is mainly isobutanol and ester, and the separated oil phase is returned to a blending tank (MIX-1) of the reactive rectifying device to continuously participate in the reaction. Wastewater is extracted from the bottom of the alcohol recovery tower (DISTIL-2), and CODCr <3000 is considered as qualified.
The production method provided by the invention realizes the recycling of raw materials, the total conversion rate of the raw materials such as acrylic acid, isobutanol (sec-butyl alcohol) and the like is more than 99.5 percent, and the utilization rate is high; the reaction condition is mild, and the product selectivity is more than 98 percent. According to the selection of different processes, two grades of isobutyl acrylate (a) qualified products can be finally produced: isobutyl acrylate > 99.5%, acrylic acid 0.5%; (b) the superior products are as follows: isobutyl acrylate > 99.9% and can meet different application requirements.
The synthesis of isobutyl acrylate (equation) is an acid-catalyzed reversible reaction, and the equilibrium of the reaction is reached at a certain reaction level, so that it is necessary to further understand the present invention through a series of figures and examples, but the following examples are not intended to limit the contents of the present invention.
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