& Terms of Use. 1 shows an absorption column 12, applicable in the inventive process. An acrylic acid-depleted gas stream which flows out of the absorption column is generally also subjected to a condensation of the water vapor normally present therein. From the stripping unit 44 a feed stream F 2 is introduced into a rectification column 4, comprising a rectifying section 6 and a stripping section 8. Optionally, substances which complex metals, for example EDTA, can be added to the bottom liquid in the bottom space of the absorption column. x�+� � | BASF is one of the largest producers of crude acrylic acid (CAA). 2 shows a flow chart of a preferred embodiment of the inventive process, FIGS. Presently, acrylic acid is produced by the oxidation of … Advantageously in accordance with the invention, the boiling point of the absorbent at standard pressure is at least 20° C., preferably at least 50° C., more preferably at least 75° C. and most preferably at least 100° C. or at least 125° C. above the boiling point of acrylic acid, which is 141° C. at 1 atm, at the same pressure. The fraction containing the acrylic acid is removed in the middle part of the column, via one or more side take-offs. BASF is the world’s largest producer of acrylic acid and has substantial capabilities in its production and downstream processing. Acrylic acid is removed via the side take-off. For the process according to the invention, particular preference is also given to absorbents which consist to an extent of at least 70% by weight of those organic molecules which do not comprise any externally active polar groups and are therefore, for example, incapable of forming hydrogen bonds. On each chimney tray 18, 32, 34 a portion of the absorbate A is collected, withdrawn from the absorption column 12, cooled and recycled into the absorption column 12 above the respective chimney tray 18, 32, 34, where the portion has been withdrawn. This leadership position enables BASF to be a strong and reliable partner for its customers. Possible sources for a metal contamination as described above include especially the catalyst bed used for the heterogeneously catalyzed partial gas phase oxidation and the manufacturing materials used for the equipment involved. Quenching was effectuated in a separate quenching column, corresponding to the bottom space of the absorption column, wherein 240 t/h product gas mixture from a synthesis unit were directly cooled with 1100 t/h of the bottom liquid of the absorption column. <>/XObject<>/ExtGState<>/ColorSpace<>>>/Annots[36 0 R 37 0 R 38 0 R 39 0 R 40 0 R 41 0 R 42 0 R 43 0 R 44 0 R 45 0 R 46 0 R 47 0 R 48 0 R 49 0 R 50 0 R 51 0 R 52 0 R 53 0 R 54 0 R 55 0 R 56 0 R 57 0 R 58 0 R 59 0 R 60 0 R 61 0 R 62 0 R 63 0 R 64 0 R 65 0 R 66 0 R 67 0 R 68 0 R 69 0 R 70 0 R 71 0 R 72 0 R 73 0 R 74 0 R 75 0 R 76 0 R 77 0 R 78 0 R 79 0 R 80 0 R]/Tabs/S/StructParents 2>> <>/ColorSpace<>>>/Annots[139 0 R 140 0 R 141 0 R 142 0 R 143 0 R 144 0 R 145 0 R 146 0 R 147 0 R 148 0 R 149 0 R 150 0 R 151 0 R 152 0 R 153 0 R 154 0 R 155 0 R 156 0 R 157 0 R 158 0 R 159 0 R 160 0 R 161 0 R 162 0 R 163 0 R 164 0 R 165 0 R 166 0 R 167 0 R 168 0 R 169 0 R 170 0 R 171 0 R 172 0 R 173 0 R 174 0 R 175 0 R 176 0 R 177 0 R 178 0 R 179 0 R 180 0 R 181 0 R 182 0 R 183 0 R 184 0 R 185 0 R 186 0 R 187 0 R 188 0 R 189 0 R 190 0 R 191 0 R]/Tabs/S/StructParents 4>> The variation of the eluent over the elution time ensures an increased separating action (in general, the liquid phase to be analyzed, as well as glyoxal, also comprises other by-product aldehydes and/or by-product ketones which form the particular corresponding hydrazone with 2,4-dinitrophenyl-hydrazine). The air cooler can comprise fine tubes in which the withdrawn mixture to be cooled is conducted from the top downward and which are supplied from outside with ambient air with the aid of ventilators. Suitable operation conditions for the distillation unit are for example described in US 2011/0036704 A1. Indirect heat exchangers have at least one primary space and at least one secondary space. The boiling point of these high-boiling secondary constituents is, both at standard pressure and under the conditions of the distillation, typically above that of the absorbent. Np;N�R�l�8-��4�|tsrl��ι��Qj�:��#��|Vz|~]�����5. endobj Absorbents which are particularly favorable in accordance with the invention are, for example, diphenyl ether, diphenyl, corresponding to biphenyl, mixtures, known as Diphyl® and consisting of 70% to 75% by weight of diphenyl ether and 25% to 30% by weight of diphenyl, and also dimethyl phthalate, diethyl phthalate and mixtures of a first constituent, the first constituent consisting of 70% to 75% by weight of diphenyl ether and 25% to 30% by weight diphenyl, and dimethyl phthalate or the first constituent, the first constituent consisting of 70% to 75% by weight of diphenyl ether and 25% to 30% by weight diphenyl, and diethyl phthalate or the first constituent, the first constituent consisting of 70% to 75% by weight of diphenyl ether and 25% to 30% by weight diphenyl, dimethyl phthalate and diethyl phthalate. Reaction and quench.Chemical-grade (CG) propylene is mixed with steam and air and fed to a two-step oxidation reaction system. 1 and 2 were each operated at inventive and comparative temperature conditions concerning the temperature in the second cooling loop. The most commonly used processes are based on Nippon Shokubai, BASF, BP (Sohio), and Mitsubishi catalysts or technologies. <>/ColorSpace<>>>/Tabs/S/StructParents 1>> To this end, 2.0 g of a 50% by weight solution of 2,4-dinitrophenylhydrazine, available for example from Aldrich with a purity of at least 97%, are dissolved at a temperature of 25° C. in 62 ml of a 37.0% by weight aqueous hydrochloric acid, available for example from Aldrich with a purity of at least 99.999%. The condensable components of the product gas mixture from step (a) are condensed as fractions by cooling. BASF, Cargill and Novozymes have signed an agreement to develop technologies to produce acrylic acid from renewable raw materials. A process for preparing aqueous solutions of homo- or copolymers of acrylic acid by means of free-radical polymerization of acrylic acid and optionally water-soluble, monoethylenically unsaturated comonomers in an aqueous medium in the presence of at least one water-soluble initiator and of at least one water-soluble regulator, where the amount of acrylic acid is at least 50% by weight based on the … A larger distance between two vertical lines indicates that longer runtimes between two shutdowns were possible. FIG. After the air cooler 26 and before the withdrawn portion of the absorbate A is recycled from the second cooling loop 16 into the absorption column 12, the temperature of the cooled portion of the absorbate A is measured by a temperature sensor 36. FIG. Prior to this recycling, it is appropriate to extract a portion with acid water. The adsorption column preferably has baffles which effect separation, in particular having packings and/or trays, preferably bubble trays, sieve trays, valve trays and/or dual-flow trays. <>/SpiderInfo 279 0 R>> Preferably, the absorbent is a high-boiling adsorbent. %���� Above the third chimney tray 11 fixed valve trays were present. From the bottom space 22, a bottom liquid comprising the absorbent is withdrawn as a stream 40. US3002017A US826768A US82676859A US3002017A US 3002017 A US3002017 A US 3002017A US 826768 A US826768 A US 826768A US 82676859 A US82676859 A US 82676859A US 3002017 A US3002017 A US 3002017A Authority US United States Prior art keywords acrylic acid temperature homopolymer cooled beta Prior art date 1959-07-13 Legal status (The legal status is an assumption … In general, the high-boiling absorbents are organic liquids. e) enriching the absorbent in the stripping section and enriching acrylic acid in the rectifying section. The precooled product gas mixture ascends in the absorption column 12 and is contacted with an absorbent in a countercurrent mode. %PDF-1.6 In the first plant, according to FIG. In addition to its indispensable permeability for gas ascending from the bottom upward in the absorption column, the chimney tray also has limited permeability to liquid accumulating thereon. 3 0 obj After stirring at 25° C. for 1 hour, the derivatization solution D is obtained by filtration as the resulting filtrate. In general, the water vapor content of the starting reaction gas mixture will, however, not be more than 40% by weight, frequently not more than 30% by weight. endobj However, it shall also include desorption, corresponding to the removal of an absorbed low boiler from the absorbate, by, for example, heating or by reducing the pressure in the gas phase. In August 2012, BASF, Cargill and Novozymes announced their joint agreement to develop a process for the conversion of renewable raw materials into bio-based acrylic acid. “3-HP is a potential key raw material for the production of bio-based acrylic acid which is a precursor of superabsorbent polymers,” said Teressa Szelest, Senior Vice President Global Hygiene Business at BASF. BASF’s role in the enlarged collaboration will be to develop a process to convert 3-HP into acrylic acid. 9 0 obj BASF is the world's largest producer of acrylic acid and has substantial capabilities in its production and downstream processing. 2 0 obj At a side take-off at the first cooling loop, 230 t/h of absorbate A were withdrawn from the absorption column and conducted towards the rectification column. In the first step, the propylene is oxidized to acrolein a… The recycled, condensed high boiler fraction is fed countercurrent to the ascending gas. The process water taken from BASF Petronas Chemicals Sdn Bhd containing 4% acrylic acid is used as sample water in this study. The invention is related to a process for production of acrylic acid comprising the following steps: OBLON, MCCLELLAND, MAIER & NEUSTADT, L.L.P. The absorption column 12, comprises three cooling loops 14, 16, 24. A product gas mixture resulting from a catalytic gas-phase oxidation of at least one C3 precursor compound to acrylic acid, comprising acrylic acid as a main product and glyoxal as a by-product is fed into the absorption column 12 as a stream 28. an acrylic acid price of $1.75/lb. Appropriately, the process for heterogeneously catalyzed partial gas phase oxidation will therefore be performed as detailed in WO 2005/042459 or in WO 2005/113127 using the example of a two-stage heterogeneously catalyzed partial gas phase oxidation of propene to acrylic acid. 4 0 obj The materials used for the equipment involved are especially those recommended in DE-A 10336386. A second portion of stream 40 is purified and recycled into the absorption column as a stream 42. If the product price decreases by 45% to $1.20/lb (the current market price of acrylic acid), the estimated IRR will be 45% with a NPV of $114,552,700 at a 15% discount rate. Prior to the aforementioned further use as stripping gas, it is preferably scrubbed with absorbent conducted out of the stripping section of the rectification column, before the latter is recycled into the absorption column. Between the first cooling loop and the side take-off, distillative concentration and condensation of the high boiler fraction from the gas stream fed countercurrent upward are effected toward the first cooling loop. This route is also being pursued by biobased chemicals start-up OPX Biotechnologies . A shutdown was necessary regularly after 10 to 20 days for polymer removal. <> endobj Preferably, the second cooling loop comprises an indirect heat exchanger, more preferably an air cooler. (ALEXANDRIA, VA, US), 1. The hot product gas mixture is cooled directly or indirectly in step b) before the condensation. By the temperature increase, the glyoxal concentration in the crude acrylic acid was reduced from up to 90 weight ppm to a glyoxal concentration of less than 30 weight ppm resulting in runtimes of up to 50 days. It can be reacted with alcohols to form esters know as acrylates. The supply of the bottom liquid withdrawn from the bottom space of the absorption column to the distillation unit is for the purpose of recovering absorbent present in the bottom liquid, before undesired high-boiling by-products, which also comprise high-boiling secondary constituents are discharged from the process for removal of acrylic acid as described in for example DE-A 24 49 780. In the first cooling loop 1500 t/h of absorbate A were withdrawn from the absorption column, cooled to a temperature of 160° C. and recycled back into the absorption column. 4 is assigned to a second plant. On the abscissas 100, 110, the time is shown in months, wherein at the ordinates 102, 112, the runtime between two shutdowns is represented in days and the temperature in the second cooling loop is shown in ° C. The abscissa 112 in FIG. 11 0 obj 210 t/h of the absorbent A were led through the second chimney tray towards the first chimney tray. As separating internals between the chimney trays, tray types known by the person skilled in the art are applicable such as tunnel trays, fixed valve trays, sieving trays or bubble cap trays or packings. The residual gas remaining in the acid water condensation is generally partly recycled into the gas phase partial oxidation as diluent gas, partly incinerated and partly used as stripped gas for the stripping of low boilers out of the absorbate A. The entire contents of the screwtop bottle are then mixed by shaking and then left at a temperature of 25° C. for a period of 10 minutes. Tube-bundle heat exchangers, plate-type heat exchangers and air coolers are preferred. BASF is the world’s largest producer of acrylic acid and has substantial capabilities in its production and downstream processing. “After just 18 months havewe selected the preferred process to convert 3HP into glacial acrylic acid- . The company plans initially to use the bio-based acrylic acid to manufacture superabsorbent polymers. Suitable diethyl phthalate for this purpose is, for example, at least 99% by weight diethyl phthalate from BASF SE. <> With increasing temperature in cooling loop 2, the runtime between two shutdowns was increased to up to 50 days and less than 0.1 tons of polymer had to be removed during shutdowns. The shutdowns were effectuated at the latest possible point of time, when too much polymer was accumulated in the rectification column and the pressure difference in the rectification column therefore increased. It is also possible to proceed as described in the flow diagrams of DE-A 19606877 and DE-A 1960687. The process is predicted to become profitable in year 3. Grey squares 106, 116 stand for the amount of polymer in tons, which had to be removed at the corresponding shutdown. 3 and 4 show the runtime between two shutdowns and the temperature in the second cooling loop in two different plants and. The molar amount thereof results directly in the molar amount of glyoxal present in the sample of the liquid phase to be analyzed: Chromatography column to be used: Waters Symmetry C18, 150×4.6 mm, 5 μm, from Waters Associates, Milford, Mass., USA; Injection volume of the solution to be analyzed: 50 μl at time t=0; Eluent flow rate: 1.5 ml/min; Analysis time: 17 min; Equilibration time: 8 min; in the period t from more than 0 min to 15 min, a mixture of 30% by weight of acetonitrile, 50% by weight of water and 20% by weight of tetrahydrofuran, each HPLC grade; in the period from more than 15 min to 17 min, a mixture of 65% by weight of acetonitrile, 30% by weight of water and 5% by weight of tetrahydrofuran; in the period from more than 17 min to 25 min, a mixture of 30% by weight of acetonitrile, 50% by weight of water and 20% by weight of tetrahydrofuran. Circles 104, 114 represent the temperature of the absorbate A in the second cooling loop before re-entering the absorption column. 245 t/h cycle gas were withdrawn from the upper part of the absorption column. endobj It will be appreciated that aforementioned water vapor contents also promote the formation of glyoxal hydrates. 3, the temperature in the second cooling loop was enhanced to a temperatures between 62° C. and 63.5° C. after approximately 14 months. The cooling liquid enters the absorption column 12 as a stream 30. The acid water extract obtained is advantageously stripped with residual gas to be supplied to the incineration thereof. .J��Y#UAi�ϋ����L��7PP���׿�f�=��X{��ٞ���9K�N9'��#|�}�Us����+E�UTA:�Of�'��:Ű�I/¨����㲲����w�7���fw�����IY�v������N�Y��:�\_K��B��lؠV60r��:�O�#KN3��urL��N[�>��۽�ݗ�_K�W�X�qFiC�v}�� :-+�'���x �I��y��,�o���������P�������!|N�sq:*+'N� %��.�>9J�u�ޖ^��)\���q�a���'$�C�����E�ʧ��>�7��?U�J�[�$M Currently, acrylic acid is produced by the oxidation of propylene derived mainly from the refining of crude oil. Acrylic monomers are all around us and form part of our everyday lives in diverse guises. 3 and 4 by a vertical line. Normally, the total amount of mixture G added in order to bring about the dissolution of the precipitate does not exceed 5 g. All above dissolution tests are carried out at 25° C. The solution of the hydrazone H obtained in the screwtop bottle as described is subsequently analyzed for its hydrazone content by means of HPLC using the following operating conditions. The chimney tray can also be described as collecting trail. In general, the boiling point of the absorbent used for the process according to the invention at standard pressure is at values of at least 400° C., frequently at least 350° C. and in many cases also at least 300° C. or at least 280° C. In a manner particularly suitable for the process according to the invention, the boiling point of the absorbent used for the process according to the invention, at standard pressure, is at values in the range from 200° C. to 350° C., preferably in the range from 200° C. to 300° C. For example, useful absorbents include all of those which satisfy the aforementioned boundary conditions and are recommended in the documents DE-A 103 36 386, DE-A 024 49 780, DE-A 196 27 850, DE-A 198 10 962, DE-A 043 08 087, EP-A 0 722 926 and DE-A 044 36 243. Each cooling loop 14, 16, 24 comprises a chimney tray 18, 32, 34. During this time, the corresponding hydrazone H of monomeric glyoxal forms from the monomeric glyoxal present in the screwtop bottle by chemical reaction with 2,4-dinitrophenylhydrazine. It has the capacity to produce 160,000t of acrylic acid a year. endobj BASF is the world´s largest producer of acrylic acid and has substantial capabilities in its production and downstream processing. Diamonds 108, 118 indicate the number of days of the runtime between two shutdowns. & Terms of Use. In principle, however, it is also possible to strip as in EP-A 1041062. 7 0 obj On the secondary ordinates 103, 113, the amount of polymer, which had to be removed at each shutdown, is given in tons. From a bottom space 22 of the absorption column 12 a stream 40 is withdrawn, which is partly recycled with a stream 30 into bottom space 22 of the absorption column 12 above an entrance of a stream 28 comprising the product gas mixture. Most acrylic acid is converted into commodity esters from crude acrylic acid (CAA),generally >97% purity. As a consequence, there may be a discharge of fine catalyst dust with the reaction gas mixture. The resulting condensate is referred to as acid water. 8 0 obj These by-products to be discharged from the removal process include, for example, also polymers of acrylic acid which form in an unavoidable manner only in the course of the performance of the removal process, and resinified cracking products of the absorbent, but also polymerization inhibitors and any catalyst dust present in the product gas mixture of the partial oxidation. The circulation heat exchanger of the distillation unit is understood to mean an indirect heat exchanger present outside the distillation column. 6 0 obj Glacial Acrylic Acid or prop-2-enoic acid is the starting point for all other acrylics chemistry. For example, the stripping can be performed in analogy to the remarks in DE-A 4308087 and in DE-C 2136396. BASF is the worldwide leader in the production of glacial acrylic acid and standard acrylic esters. Since the acrylic acid-containing gas mixture contains a plurality of fractions, it is expedient to install a plurality of cooling apparatuses in various sections of the column, for example a cooling apparatus in the lower section of the column for condensing the high boiler fraction and a cooling apparatus at the top of the column for condensing the low boiler fraction. BASF has now joined the collaboration to develop the process for conversion of 3-HP into acrylic acid. Preferably, this proportion by weight is less than 1 ppm by weight per metal or per heavy metal or per transition metal, based on the weight of the bottom liquid. In the plants, the absorption column comprised 13 fixed valve trays between the first and the second chimney tray and 21 fixed valve trays between the second and the third chimney tray. “3-HP is a potential key raw material for the production of bio-based acrylic acid which is a precursor of superabsorbent polymers,” said Teressa Szelest, Senior Vice President Global Hygiene Business at BASF. The inventive process preferably further comprises a stripping unit, wherein low boilers are stripped out of the absorbate A in the stripping unit between step c) and step d). endobj This process is described in the next paragraphs. FIG. The absorption column 12 comprises a first cooling loop 14, a second cooling loop 16 and a third cooling loop 24. Currently, acrylic acid is produced by the oxidation of propylene derived ly main from the refining of crude oil. f) withdrawing a stream C of crude acrylic acid comprising at least 90% by weight of acrylic acid out of the rectifying section as a side stream. ACRYLIC ACID A SUMMARY OF SAFETY AND HANDLING 3RD EDITION Compiled by BASF Corporation Celanese, Ltd. Elf Atochem North America, Inc. Rohm & … The conventional method to produce acrylic acid is by the two-stage catalytic oxidation of propylene. Based on the data from the first plant, FIG. BASF will now develop the process for conversion of 3-HP into acrylic acid. Then the column is equilibrated and ready for use again for the next analysis. Further, from the bottom space of the absorption column 62 kg/h of the bottom liquid, which was enriched in high boiling impurities, were withdrawn from the absorption column and removed from the process. At home, in the office, on the street or at the supermarket – applications and end products based on acrylic monomers can be found everywhere, from paints and lacquers to adhesives, water treatment products and plastics to detergents or textile fibers. More preferably, a stream of the vapors, optionally after cooling and/or condensation thereof in an undirect heat exchanger, is recycled into the absorption column above the first chimney tray, most preferably above the second chimney tray. Acrylic acid is a high-volume chemical that feeds into a broad range of products. The analysis is effected by means of monochromatic radiation of wavelength 365 nm. 5 shows the dependency of the glyoxal concentration on the temperature. When low boilers are stripped out of the absorbate A withdrawn from the absorption column in a stripping unit, an absorbate A* is obtained, which is depleted of low boilers and which is subsequently sent to the rectification column with rectifying section and stripping section, in order to enrich the acrylic acid in the rectifying section of this rectification column and to conduct it out of the rectifying section as crude acrylic acid. BASF initially to use the bioplans based acrylic acid to manufacture superabsorbent - polymers. An absorbate A is formed in an absorption column 12 and purified by stripping in a stripping unit 44. 2 shows a preferred embodiment of the inventive process. The company plans initially to use the bio-based acrylic acid to manufacture superabsorbent polymers. This is in particular because the catalysts used as active materials for the partial oxidation are normally multimetal oxide materials comprising Mo, Bi and Fe and/or multimetal oxide materials comprising Mo and V. Owing to its water vapor content, the reaction mixture is capable, for example, of promoting the discharge of molybdenum oxides from the active materials. Advantageously, however, a forced circulation evaporator or forced circulation heat exchanger is used according to for example FIG. Presently, acrylic acid … Preferably, in the distillation column, the bottom liquid of the absorption column fed to the distillation unit is separated by distillation into vapor, in which the proportion by weight of absorbent is greater than the proportion by weight of absorbent in the bottom liquid of the absorption column, and into liquid concentrate, in which the proportion by weight of constituents with higher boiling point than the absorbent, under distillation conditions, is greater than the proportion by weight of these constituents in the bottom liquid of the absorption column. BASF plans initially to use the bio-based acrylic acid to manufacture superabsorbent polymers that can soak up large amounts of liquid and are used mainly in baby diapers and other hygiene products. For cooling, the second cooling loop 16 comprises an air cooler 26. Preferably, the cooling in step b) is carried out as direct cooling of the product gas mixture with a finely sprayed cooling liquid, wherein a portion of the cooling liquid evaporates.