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acrylic acid production from propylene

The gaseous reaction product in the first-stage reactor leaves the reactor, and through a line 6, enters a heat exchange 104 where it is rapidly cooled without undergoing condensation. Acrylic acid from the primary oxidation can be recovered while the acrolein is fed to a second step to make acrylic acid. 3,766,265, and German Laid-Open Patent Publication Specification Nos. In the process of U.S. Pat. The compositions of these catalysts excepting oxygen, in terms of atomic ratio, were as follows: Catalyst (I): co4 Fe1 Bi1 W2 Mo10 Si1.35 Mg0.04, Catalyst (II): mo12 V4.8 Ba0.5 Cu2.2 W2.4. A route to acrylic acid production is through an acrolein intermediate as illustrated by reaction schemes 6 and 7. endobj Elsewhere, the process idsclosed in Japanese Laid-Open Patent Publication No. After 100 hours from the start of the reaction, the conversion of proplyene decreased to 85%, and the starting reactant gas at the inlet of the first-stage reactor contained 0.7% by volume of acrylic acid. The most widely accepted process for making acrylic acid is the vapor phase oxidation of propylene. The compositions of these catalysts excepting oxygen, in terms of atomic ratio, were as follows: Catalyst (I): co5 Fe0.35 Bi1 W2 Mo10 Si1.35 K0.06. For example, by the process disclosed in U.S. Pat. Hence, a heat exchanger 108 for controlling the temperature of the supply water is provided, or a heat exchanger (not shown) capable of heating or cooling the liquid falling down in the acrylic acid collector 107 is provided interiorly or exteriorly of the collector. The starting reactant gas mixture to be introduced into the first-stage reactor contained 0.13% by colume of acrylic acid. For example, U.S. Pat. The inventors also performed an experiment on a so-called oxygen method in which to use gaseous oxygen instead of air as a source of molecular oxygen. Furthermore, the amount of oxygen in the reaction system becomes excessive. Thus, it was ascertained that acrylic acid cannot be produced generally in high yields by the complete recycle method in accordance with the oxygen method. in simplifying the kinetics to only one reaction. The exhaust gas to be reused for the reaction passes through a line 12, and is increased in pressure by a blower 109. The process of claim 1 wherein the acrylic acid is recovered from the acrylic acid collector in the form of a 30 to... 3. The invention is described more specifically by reference to the accompanying drawing which is a flowsheet illustrating one preferred embodiment of the process of the present invention. ��0�idIqf攬C7,AаW}/g��!+���Xz䴋X)��o3�ŨM���7�.�2/���� ���]����74x��s�T.Mʹz�@� /Filter /LZWDecode It has not yet been known which of these impurities causes catalyst degradation. water = 1.15 kmol/hr solvent = 10.82kmol/hr Production of Acrylic Acid form propylene. The tower top temperature so set is 35° to 80° C., preferably 40° to 70° C. If the tower top temperature is set at a lower point, that is below 35° C., the amount of the recycle gas increases as a result of supplying a specified amount of steam, and the amount of oxygen to be supplied is insufficient. During this time, an aqueous solution of acrylic acid in a concentration of 30 to 32% by weight was obtained, but the rate of acrylic acid collection decreased to 88%. one-step reaction from propylene to acrylic acid when in reality, propylene is first oxidized to acrolein and then acrolein to acrylic acid. According to the process disclosed in Japanese Laid-Open Patent Publication No. � Acrylic acid is produced via the catalytic partial oxidation of propylene. More particularly, the invention relates to a process for producing an aqueous solution of acrylic acid of a high concentration by oxidation of propylene at a high concentration and also providing with prolonged catalytic activity a Mo-Bi composite oxide catalyst used for vapor phase … These catalysts are disclosed, for example, in U.S. Pat. When a large amount of flowing water was used in order to raise the rate of acrylic acid collection to 98-99%, the concentration of the resulting aqueous solution of acrylic acid decreased drastically. The work of the inventors, however, led to the discovery that if the acrylic acid concentration of the starting reactant gas mixture after incorporation of the exhaust gas is not more than 0.5% by volume, preferably not more than 0.3% by volume, the adverse effects of these impurities on the catalyst can almost be neglected. No. It has been the conventional practice to recycle the exhaust gas to the reaction system. Using 12.0 liters of the catalyst (I) and 9.0 liters of the catalyst (II) and the same apparatus as used in Example 1, propylene was reacted under the same reaction conditions as in Example 1 except that the reaction temperatures were varied as shown in the following table. /Length 9 0 R The gaseous reaction product in the second-stage reactor passes through a line 8, and enters a heat exchanger 106 where it is rapidly cooled. 1 986. During the operation, a gaseous mixture consisting of 5.5% by volume of propylene, 10.0% by volume of steam, 12.5% by volume of oxygen, a small amount of the reaction product and the remainder being nitrogen was introduced into the first-stage reactor at a rate of 16.2 m3 /h (calculated on NTP). 9 0 obj (� �ʔFQ#�U�Tև4�V�;y+�J�@Ɛ��U The proportion of that part of the exhaust gas from the acrylic acid collector which is to be recycled to the reactor is determined according to the concentrations of propylene, steam and oxygen in the starting reactant gas mixture, and the tower top temperature of the acrylic acid collector. The catalytic vapor phase oxidation of propylene to acrylic acid usually consists of two stages. 3,775,474 affords acrylic acid in a one-pass yield of 90 mole% when using catalytic oxides containing molybdenum, vanadium, chromium, tungsten and copper as constituent elements. The reactions for acrylic acid production from propylene are as follows: In the acrylic production plant, the propylene is fed from a storage tank at a rate of 127 kmol/hr and 10 bar, which is mixed with compressed air is compressed as a source of oxygen from atmospheric conditions, to 5 bar. Consequently, adverse effects, such as reduced catalytic acitivity, are exerted on the catalytic reaction. As is clear from the above description, the process of the present invention is characterized in that a recycle exhaust gas containing a large quantity of steam is prepared by substantially preventing the condensation of steam contained in the gaseous reaction product introduced into the acrylic acid collector, and by stripping water from the aqueous solution of acrylic acid, and this exhaust recycle gas is reused in the reaction. At this time, the temperature of the tower top of the acrylic acid collector was 64° C., and the proportion of the recycle gas was 42.4% based on the exhaust gas obtained. German Patent Publication No. Acrylic Acid Production via the Catalytic Partial Oxidation of Propylene Process Information Background Acrylic acid (AA) is used as a precursor for a wide variety of chemicals in the polymers and textile industries. www.entrepreneurindia.co. 1986-StudentDesignContent-Production-of-Crude-Acrylic-Acid-from-Propylene.pdf. As a result, according to the process of the present invention, the reaction conditions in the first-stage reactor and the second stage reactor are maintained stable, and an aqueous solution of acrylic acid in a concentration of 20 to 70% by weight, preferably 30 to 60% by weight, can be withdrawn from the bottom of the acrylic acid collector. Edited by Scott Jenkins Editor’s Note: The content for this column is supplied by Intratec Solutions LLC (Houston; www.intratec.us) and edited by Chemical Engineering. The procedure of Example 1 was repeated except that the composition of the starting reactant gas mixture, the reaction pressure, the tower top temperature of the acrylic acid collector, and the proportion of the recycle gas was changed so as shown in the following table. % acetic acid Bottom product is 99.5 wt.% acrylic acid. The gaseous product from the second-stage reactor was introduced into the collector from below, and the acrylic acid in the gaseous product was collected as an aqueous solution by flowing down water containing a polymerization inhibitor from the topmost part of the tower. & Terms of Use. The catalyst for the first-stage reaction (12.0 liters) was packed uniformly into the tube of the reactor, and heated to 325° C. Separately, 9.0 liters of the catalyst for the second-stage reaction was packed uniformly into the tube of the same type of multi-tubular reactor as the first-stage reaction, and heated to 260° C. The two reactors were connected by a conduit equipped with a heat exchanger so as to introduce the gaseous reaction product from the first-stage reactor into the second-stage reactor. B�q�E����ap�4�&�slbe4�'��x���Q� The exhaust gas to be discharged passes through a line 11, and after being rendered non-polluting by, for example, being completely burned by using a catalyst, it is discharged into the atmosphere. Further investigations into these conditions led to the discovery that acrylic acid can be obtained in high yields over long periods of time with commercial advantage only when the temperature of the tower top of the acrylic acid collector is adjusted to 35°-80° C., and the proportion of the recycle gas is adjusted to 15 to 85%. It was found that almost all of the exhaust gas can be recycled, but light-boiling impurities (e.g., carbon dioxide, carbon monoxide, and hydrogen) are concentrated to about 40 times or more in the gas circulating through the reactor, and cause gradual degradation of the catalyst performance during operation for long periods of time. The greatest characteristic feature of the process of this invention is that the exhaust gas discharged from the acrylic acid collector after the recovery of acrylic acid from the gaseous reaction product is adjusted to a specified steam content, and then incorporated in the starting reactant gas mixture as a diluent for preventing its combustion. In the same way as in Example 1, a catalyst (I) for the first-stage reaction and a catalyst (II) for the second-stage reaction were prepared. Feed: Acrylic Acid = 11.53kmol/hr Acetic acid = 1.508 kmol/hr Top product: Acrylic Acid = 1.488kmol/hr The upper portion is of a structure of a plate tower or a packed tower where acrylic acid in the gaseous product is caused to be absorbed by water, and water is stripped by the exhaust gas. This assumption is based on the inventors' finding that the conversion of propylene decreases when acid substances such as acrylic acid make contact with the catalyst of the first-stage reactor, and attempting to increase the conversion by raising the reaction temperature tends to result in reduced selectivity. Ordinary water is used as the water from the line 16. Goal is to produce 200 TPD of 99.0% acrylic acid utilizing 8000 hours a year. ����x��‰��/^��h�������'��h�ılo� ��M���2?����K���M��ֽ~����4 �͜��� The exhaust gas obtained in the collector 107 is withdrawn through a conduit 10 kept warm so as not to condense moisture in the gas. /Contents 8 0 R conducting the propylene oxidation in the first-stage reactor in the presence of 5 to 25% by volume of steam, substantially all of the steam except the steam in the starting gas reaction mixture being fed to the first-stage reactor being contained in the recycled exhaust gas discharged from the acrylic acid collector. A design feasibility study is presented to analyze the There are several chemical pathways to produce AA, but the most common one is via the partial oxidation of propylene. 1,924,496 states that steam is used as a diluent in a reaction of oxidizing acrolein to acrylic acid in order to perform the reaction selectively and narrow the flammable range of the reaction gas. Follow AIChE. nitric acid and 3 liters of water. & Terms of Use. It also can react with alcohols to form acrylates (esters) that are … The present inventors extensively worked on the re-use of the exhaust gas an an inert diluting gas for the reaction, and found that the conditions for obtaining the exhaust gas and the conditions for re-using the exhaust gas (the proportion of the recycle gas) are of utmost importance. >> %���� These reports are intended to be In these types of acrylic acid collectors, the temperature of the tower top is set within the range of temperatures at which acrylic acid is recovered from the gaseous reaction product with good efficiency as a high concentration aqueous solution of acrylic acid and at which the concentration of steam in the starting reactant gas mixture reaches a predetermined value. As a result of searching for its cause, it was found that the reduction of the catalyst performance is ascribable to impurities (e.g., the unrecovered acrylic acid, acetic acid, and aldehydes) in the exhaust gas. The object of the invention is achieved by a process which comprises passing a starting reactant gas mixture containing propylene, a molecular oxygen-containing gas and steam through a first-stage reactor packed with a molybdenum-containing multi-component catalyst, passing the resulting acrolein-containing gas through a second-stage reactor packed with a multi-component catayst containing vanadium and molybdenum, introducing the resulting acrylic acid-containing gas to an acrylic acid collector thereby to recover acrylic acid in the form of an aqueous solution, and incorporating a part of the exhaust gas from the collector in the starting reactant gas mixture; wherein. The gaseous reaction product in the first-stage reaction can be used as a starting gas in the second-stage reaction as it contains by-product acrylic acid.. *��&�;���R�a��I�b��H�41�E�ܷm����J�R �h�v������R�Ɏ��� ˒62�cq�=ySְ��aϲЮ+ט�ߗ�:�n�fCо[-+L�#]�8 �CB7�R3;Y No. The composition of this catalyst excepting oxygen, in terms of atomic ratio, was as follows: Mo12 V4.6 Cu2.2 Cr0.6 W2.4, reactions and the collection of acrylic acid. Acrylic acid is a relatively large volume monomer that can be made from glycerol and carries a premium price that has been about 25% more than 1,2 propanediol and epichlorohydrin. endobj %PDF-1.2 Introduction. This invention relates to a process for producing acrylic acid from propylene. conclude, the price of propylene glycol has to drop by 45−55% to make the biobased production of acrylic acid from propylene glycol economically feasible. !�m��h&\��}H�4b�a�[���G��¸g�� d HY /H8�j�!r)K�}���?%/��A����]���0��b���A>/�Daa�H��A�×��b,`AC���7&��d�vq�8��/Dv����Ň��x (�����h����#DJ�d8T�7��z+E�P $ 풯��s��et����, q3���KX��`4�P��ˢ��%��3WLi'-���ľF@`m4�$�ĺ3��F#�RS��؈�@O�3f �=��D�9lq�h0�䐔�(L]���r�{J�MN��B1^�I�,���t���$��Õ� © 2004-2021 FreePatentsOnline.com. Nevertheless, no sufficient research has been undertaken in the art about these factors. No. No. The content … The reactant gas mixture obtained is mixed in a line 3 with propylene gas fed through a line 4. Moreover, the rate of recovering acrylic acid decreases. Communities. On the other hand, when the tower top temperature exceeds 80° C., acrylic acid and other impurities are fed to the reactor together with the recycle exhaust gas, and adversely affect the catalytic reaction. When calculated on the basis of the Examples of Belgian Patent Nos. The starting reactant gas mixture then enters a first-stage reactor 103 through a line 5. A portion (6,790 liters/hr; 42.4%) of the exhaust gas was taken out, and mixed with 8,350 liters/hr of air and 890 liters/hr of propylene to form a starting reactant gas mixture. Generally, in order to produce acrylic acid with good commercial efficiency by catalytic vapor phase oxidation of propylene, it is necessary to use catalysts which give high conversions of propylene and have high selectivities to acrolein and acrylic acid, and also to employ the most economical process for catalytic vapor phase oxidation reaction. conducting the oxidation of propylene in the first-stage reactor in the presence of 4 to 30% by volume of steam substantially all of the steam except the steam in the starting reactant gas mixture being fed to the first-stage reactor being contained in the recycled exhaust gas discharged from the acrylic acid collector. However, the discovery of new natural gas reserves presents new opportunities for the production of acrylic acid. r.��(�JU2����uz��g[���rP�r8���֋-�A�SF#���s�T!p�. The following Examples and Comparative Examples illustrate the present invention in greater detail. >> Acrylic Acid Production from Propylene. U.S. Pat. Hence, conditions for obtaining the exhaust gas and conditions for recycling it to the reactor, namely, the operating conditions in the acrylic acid collector and the recycling rate of the exhaust gas to the reactor, are important, and the present invention has offered a solution to this problem. With the closure of acetylene-based and acrylonitrile-based plants in the 1990s, the producon of acrylic acid via two-stage propylene oxidation became the preferred and dominant method of production for acrylic acid … The tower top temperature was adjusted to 64° C., and the exhaust gas was obtained. Production of Crude Acrylic Acid from Propylene. In the same way as in Example 1, a catalyst (I) for the first-stage reaction, and a catalyst (II) for the second-stage reaction were prepared. The multi-component cartalyst containing vanadium and molybdenum used in the second-stage reaction is preferably a catalyst containing vanadium, molybdenum, and at least one element selected from the group consisting of copper, tungsten, chromium and alkaline earth metals. Production of acrylic acid through the catalytic partial oxidation of propyleneis another economically viable approach.Propylene is easily available as a byproduct of cracking of naptha.Production of acrylic acid takes place by two stage selective oxidation of propylene into acrylic acid where acrolein is a fast acting intermediate. A multi-tubular reactor including 10 steel reaction tubes with an inside diameter of 25 mm and a length of 3,000 mm was used in which heat exchange was possible on the shell side by circulating molten salts. However, this process is directed to the production of acrylic acid by the oxygen method (complete recycling method), and differs from the process of the present invention in that after separation of acrylic acid as an aqueous solution, the remainder of the exhaust gas containing acrolein, propylene, steam, oxygen, etc. 3,970,702 discloses that in a reaction of oxidizing propylene to acrolein, it is desirable to incorporate steam in the starting reactant gas in an amount of about 1 to 15 moles per mole of propylene. 3,833,649 discloses that acrylic acid is obtained in a one-pass yield of 98 mole% by using catalytic oxides containing molybdenum, vanadium, chromium, and tungsten as constituent elements. The results are shown in the following table. Business Ideas & Opportunities in Petrochemicals Sector Acrylic acid (2-propenoic acid) is a highly reactive carboxylic acid that can react with itself to form polyacrylic acid, which is used as an absorbent in hygiene products. /F2 10 0 R << November 21, 2013. The acrylic acid collector used was also of the same type as used in Example 1 except that it did not include 20 trays of bubble cap. Both processes depend These are economically disadvantageous. Purification can be carried out by azeotropic distillation. 3,373,692, acrylic acid is obtained in a one-pass yield of 86 to 91 mole% by using catalytic oxides containing antimony, molybdenum, vanadium, tungsten, lead, copper, tin, titanium and bismuth as constituent elements. The three nitrate solutions were mixed, and the mixture was added dropwise to the solution A. The lower portion is of a structure of a multi-tubular heat exchanger, or a packed tower or plate tower having a heat exchanger either inside or outside. Such catalysts are disclosed, for example, In U.S. Pat. 4.10 Acid tower (design as a major equipment) Assumption: top product is 95 wt. The flow rate of water flowing down from the tower top of the collector was 3.5 kg/hr, and the rate of acrylic acid collection was 98 to 99%. Acrylic Acid Production and Manufacturing Process. The results of the reaction obtained at the end of 46 hours, and 1810 hours from the start of the operation are shown in the following table. Processes based on propylene oxidation are traditionally most employed in the production of acrylic acid. The present inventors, however, assume that unidentifiable impurities formed in the oxidation reaction are concentrated in the recycle system when the conditions specified in the invention are not met, or acrylic acid or by-product acetic acid and other impurities are again fed into the reactor together with the exhaust gas when they are not sufficiently collected, with the result that the catalytic reaction is impaired. With stirring, the mixture was evaporated to dryness, followed by calcining at 400° C. for 5 hours to form a catalyst. In the lower portion, the gaseous product fed is cooled indirectly by a cooling medium, or directly cooled by contact with a cooled aqueous solution of acrylic acid, and also humidified. __________________________________________________________________________, Reaction Composition of the starting temperature reactant gas mixture Oxygen/ Reaction (° C.) (% by volume) propylene time that 1st 2nd Acrylic (mole elapsed stage stage Propylene Steam Oxygen acid ratio) (hr). If desired, steam for adjustment purposes may come into the line 13 from a line 19. Consider the production of acrylic acid from the partial oxidation of propylene (propene). No. /ProcSet 2 0 R It has been the wide practice in this oxidation reaction to incorporate steam in the starting reactant gas in order to avoid its burning and increase the selectivity to acrylic acid as a final product. /F1 7 0 R The process disclosed in U.S. Pat. Acrylic acid (AA) is a 4.4 million metric ton-per-year global petrochemical business with an average 2011 revenue of nearly $7 billion per year. Of the operating conditions required, the operating temperature is especially important. Propylene-based acrylic acid production processescovered herein are by BASF, Nippon Shokubai (original and updated), Mitsubishi Chemical, and Lurgi/Nippon KayakuThe production . No. Hence, this causes the defect that the concentration of propylene cannot be increased in order to avoid a danger of combustion. This design followed the example of Turton and Foo et al. The "conversion," "one-pass yield," and "proportion of recycle gas" as used in the present application, are defined as follows: ##EQU1##. If this proportion is too high, the concentrations of impurities which accumulate in the reaction system increase, and adversely affect the catalyst performance or cause process inconveniences. Acrylic acid is produced by oxidation of propylene, which is a byproduct of the production of ethylene and gasoline: 2 CH 2 =CHCH 3 + 3 O 2 → 2 CH 2 =CHCO 2 H + 2 H 2 O Historical methods. Process for producing acrylic acid from propylene 1. endstream The oxidation of propylene produces acrolein, acrylic acid, acetaldehyde and carbon oxides. generation, Manufacture of acrylic acid by oxidation of propylene with oxygen-containing gases in two separate catalyst stages, <- Previous Patent (Liquid phase oxidati...). The presence of acrylic acid in the starting gas in the second-stage reaction, like the presence of steam, gives favorable results, and has an effect of substantially reducing the load of the catalyst in the second-stage reaction. Ԍ"�0�#� In the course of this investigation, the inventors found that the performance of catalyst is reduced with time. The results are tabulated below. ���Ѩ�h ���H8��D�(��� ���!��A3Dc�CNFw Acrylic acid (AA) is widely used as an intermediate of chemicals and polymer in textile industry (Xu et al., 2006).There are several alternative processes to produce it, but the most common way nowadays is the partial oxidation of propylene ().The mechanism of producing AA is that propylene is oxidized to acrolein first and then the acrolein is oxidized to AA. Acrylic Acid Production Reactions The reactions for acrylic acid production from propylene as follows: C H O C H O H O propylene acrylic acid 3 6 2 3 4 2 2 3 2 + → + (1) C H O C H O CO H O propylene acetic acid 3 6 2 2 4 2 2 2 5 2 + → + + (2) C 3 H 6 O 2 CO 2 H 2O 9 2 + → 3 + 3 (3) The exhaust gas was not condensed, and a part of it was prged. �� 1. >> For example, U.S. Pat. With the closure of acetylene-based and acrylonitrile-based plants in the 1990s, the production of acrylic acid via two-stage propylene oxidation became the preferred and dominant method of production for acrylic acid … 47917/75, acrolein is obtained in a one-pass yield of 80% by using catalytic oxides containing cobalt, iron, bismuth, tungsten, molybdenum, zinc, indium and silicon as constituent elements. Y_1442. In the present invention, the concentration of oxygen in the first-stage reactor is adjusted to 1.6-4.0 moles, preferably 1.7-3.0 moles, per mole of propylene. Using 10.8 liters of the catalyst (I) and 9.0 liters of the catalyst (II) and the same apparatus as used in Example 1, propylene was reacted under the same conditions as in Example 1 except that the reaction temperatures were changed as shown in the following table. stream Separately, an aqueous solution of 1.03 kg of copper nitrate in 0.72 liter of water was prepared. No. However, the production process most used at present at commercial scale consists of the catalytic oxidation of gaseous propylene through the application of two process stages [2]: Catalytic oxidation of propylene to acrolein: 2CH 2 =CHCH 3 +O 2 →2CH 2 =CHCHO+H 2 O Catalytic oxidation of the acrolein to acrylic acid: 2CH r��jDAS�!�m�#�m��Y`h��?0���&@ Renewable Acrylic Acid Abstract Acrylic acid is an important industrial chemical, used as a raw material in a wide variety of consumer end products. 4 0 obj (The gaseous reaction product does not undergo condensation by rapid cooling until it reaches the line 9.). This stream consists of acrylic acid, acetic acid, water, oxygen, nitrogen, and carbon dioxide. The analyses and models presented are prepared on the basis of publicly available and non-confidential information. /Parent 5 0 R q�١g`K�f#�p��Gr�� 7�Dx"�/���+���I��},���0�4�>���p��}��Wy�^����r`�J�ϋ� ����M z���Q@L�рԡ6ښu���3�@М�H����� !�#���+�����NS�$�T����8p�%hx^�a�wA)j�N��cH��Q�9N�=wW��N9���T�hTw'(bzM�).h�Y3d�\h����R�9��'��&'(�E�N��O�TܥF d�s��\e��4�W�3EC�f�x��#��"��!ΐ`iy��q��v��Oͧ�������h�e�u�c�MFx�Dm�?��QםH���&��W�B��Ѯ�����qߠ9w�Rb{���Tow�`_���Q�2p� �Sf��Ʊև�O)��i�o(��� The molybdenum-containing multi-component catalyst used in the first-stage reaction is preferably a catalyst containing molybdenum, iron and bismuth, more preferably a catalyst containing molybdenum, cobalt, iron, bismuth and at least one element selected from the group consisting of alkali metals, alkaline earth metals, thallium, tungsten and silicon. Privacy Policy Usually, the amount of the recycle exhaust gas is 15 to 85%, preferably 18 to 70%, based on the exhaust gas. >> A process for producing acrylic acid from propylene through acrolein as an intermediate by catalytic vapor phase oxidation, which comprises passing a starting reactant gas mixture containing propylene, a molecular oxygen-containing gas and steam through a first-stage reactor packed with a molybdenum-containing multi-component catalyst, passing the resulting acrolein-containing gas through a second-stage reactor packed with a multi-component catalyst containing vanadium and molybdenum, introducing the resulting acrylic acid-containing gas to an acrylic acid collector thereby to recover acrylic acid in the form of an aqueous solution, and incorporating a part of the exhaust gas from the collector in the starting reactant gas mixture. The supply water originates from a line 16, and before entering the collector 107, it is mixed with a polymerization inhibitor from a line 15 and after advancing through a line 17, the mixture is optionally heated at a heat-exchanger 108. For example, in the process disclosed in U.S. Pat. One of the typical processes for industrial production is as follows. Air is fed from a blower 101, passed through a line 1, heated at a preheated 102, and then mixed in a line 2 with a recycle gas from a line 13. The acrylic acid collector 104 should be operated in such a manner that acrylic acid is collected as a high concentration aqueous solution of acrylic acid with good efficiency, the absorption of impurities such as acrolein is prevented to the greatest possible extent, and all the steam required for the reaction is included in the exhaust gas which is discharged from the top of the tower. www.entrepreneurindia.co. Acrylic acid was produced using the below-specified starting reactant gas and the same catalysts and reactors as used in Example 1. 3,954,855, acrylic acid is obtained in a one-pass yield of 91.7 to 97.5 mole% by using catalytic oxides containing molybdenum, vanadium, tungsten, copper and alkaline earth metals as constituent elements. In addition to these catalysts, any other catalysts can be used which meet the conditions of the second-stage reaction, namely which can achieve a one-pass yield of acrylic acid based on propylene of at least 70 mole% when the reaction is carried out at a reaction temperature of 180° to 350° C., preferably 200° to 300° C. with a contact time of 1.0 to 7.2 seconds, preferably 1.6 to 3.0 seconds. Industry has seen significant change over the past two decades enters a first-stage contained... Recycled to the solution a catalytic acitivity, are exerted on the basis of the Examples of Patent! Comparative Examples illustrate the present invention in greater detail recycled to the process disclosed in Japanese Laid-Open Publication... Is used as a source of barium tower ( design as a source of magnesium, and carbon oxides product. Barium nitrate, as a source of strontium industry has seen significant change the. Amount of waste water increases in 0.72 liter of water was prepared magnesium, and a small amount acrylic... To acrylic acid collector 107 consists of acrylic acid this causes the defect that the concentration of propylene of!, nitrogen, and the same catalysts and reactors as used in example 1 of! In greater detail and a small amount of waste water increases catalyst preparation, thallium nitrate was used as water. That is … acrylic acid ( CAA ; generally > 97 % purity of acrylic acid utilizing 8000 a. For adjustment purposes may come into the line 16 ; generally > %. To acrolein and then acrolein to acrylic acid collector 107 consists of a lower and! 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Concentration is required to convert propylene to acrylic acid conventional practice to recycle the exhaust gas was not,. Catalysts or technologies the largest single component of AA production costs gas to be introduced into the line from! Produced via the catalytic partial oxidation of propylene first-stage reactor contained 0.13 % by colume of acrylic acid decreases causes! Product stream propene ) subsequent step of separating acrylic acid is converted into commodity esters from Crude acrylic acid acetic... Least one side reaction employed in the catalyst preparation, magnesium nitrate was used as a source of.! Presented are prepared on the catalytic reaction gas containing steam in a concentration determined the. Through acrolein as an intermediate by catalytic vapor phase catalytic oxidation of propylene in two steps be recovered while acrolein... Obtained is mixed in a line 19 first stage, acrolein and then acrolein to acrylic (. Reserves presents new opportunities for the production of acrylic acid from propylene acrylic acid production through... Water, oxygen, nitrogen, and is increased in order to avoid danger... Having different functions to dryness, followed by calcining at 400° C. for 5 hours to form a.. Production and Manufacturing process the art about these factors flowing water was prepared figure 2 illustrates other pathways... Vapor phase... 2 are cooled by circulating molten heat transfer salt oxidation propylene! Publication No of new natural gas reserves presents new opportunities for the production of acrylic acid.... 2,164,905, 2,337,510, 2,344,956, 2,448,804, and barium nitrate, as a process... 95 wt water was adjusted to 64° C., and 2,459,092 traditionally employed... Transfer salt the second stage, acrylic acid from acrolein are also many with acetic,. This investigation, the amount of the reactor product stream mixed, and nitrate! Producing acrolein from propylene by circulating molten heat transfer salt two decades diameter of 200 mm different! In 0.72 liter of water was adjusted so as to obtain an acrylic acid from the top of reactor. Is recovered by the generation of steam steam for adjustment purposes may come into the first-stage contained. As illustrated by reaction schemes 6 and 7 the primary oxidation can be recovered while acrolein... Passes through a line 3 with propylene gas fed through a line.. Of combustion which the exhaust gas is recycled to the reaction system range of oxygen is... Fed to a process for producing acrylic acid utilizing 8000 hours a year are disclosed for... = 1.15 kmol/hr solvent = 10.82kmol/hr production of acrylic acid industry has seen change! Effects, such as reduced catalytic acitivity, are exerted on the catalytic vapor oxidation! Reduced catalytic acitivity, are exerted on the basis of publicly available and non-confidential information... 2 of.! Bp ( Sohio ), and strontium nitrate, as a source of thallium and... The performance of catalyst performance separately, an aqueous solution of 1.03 kg of nitrate... Is used as the water from the primary oxidation can be recovered the! Nitrate in 0.72 liter of water was adjusted so as to obtain an acrylic.. Propylene produces acrolein, acrylic acid industry has seen significant change over the past two.... New opportunities for the production of Crude acrylic acid industry has seen change. Determined by the generation of steam study is presented to analyze the the acrylic (! Are exerted on the basis of publicly available and non-confidential information acid produced as a source barium. Portion having different functions significant change over the past two decades temperature is especially important fed. Reserves presents new opportunities for the reaction system becomes excessive pressure by a blower 109 for acrylic. Line 12, and carbon oxides an inside diameter of 200 mm at the end of 520 from... A small amount of waste water increases 2,448,804, and the amount waste... Propylene can not be increased in order to avoid a danger of combustion discloses a process for producing acrolein propylene! Are shown in the reaction passes through a line 5 are based on propylene oxidation are traditionally most in.

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