Of the operating conditions required, the operating temperature is especially important. incorporating 15 to 85% of the exhaust gas into the starting reactant gas mixture so that acrylic acid content in the gas mixture is maintained at not more than 0.5% by volume; recovering acrylic acid from the acrylic acid collector in the form of a 20-70% by weight aqueous solution; and. Introduction. No. Products Acrolein, Acrylic acid, Acetic acid Standard inputs oxygen from air, Propylene Methodology: Environmental Clarity gtg lci reports are based on industrial practice information, standard methods of engineering process design, and technical reviews. 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. 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. in simplifying the kinetics to only one reaction. 4 0 obj Acrylic acid was produced using the below-specified starting reactant gas and the same catalysts and reactors as used in Example 1. The remainder was returned to a position before the first-stage reactor by a blower, and after being mixed with propylene and air, was introduced into the first-stage reactor. Production of Crude Acrylic Acid from Propylene. www.entrepreneurindia.co. The results are shown in the following table. 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. endstream �W�6��OR M�4�x�7���@�]��$�����Z�T�������ؔ� 5��5�����;:%��Zg���ϲ�NN��i�-�5��]fxu��{q'K�=U:�^\HNO�(kk��o_f4���6��U���!������-��U�����]���Ԇ���I ɇX�kbKRFn u-.h��z�����t̸C. Privacy Policy Known catalysts for producing acrylic acid from acrolein are also many. Both processes depend It has not completely been elucidated yet why in the process of the present invention, the temperature conditions for obtaining the exhaust gas and the proportion of the recycle gas in the exhaust gas obtained are so important. (j�\���Vi 2���.b©�d���y#�_c �V]��ؙk?晊�>�Y?q�v���OƑd����7�R���B����`03�T�[_�H&�ϖ/�G�] �n@\��(>)B�c���D�����#�;b���1 ��B$&B��ڪ�g�:j��H��%BGf�O�&^`�r�2d@� ��c�P�fSO��� j X�T�PJ-K� @"�e@����Ln`dp �!b� rׅN�`@�@c��E��E�bFp|����rP�6��6F��`�H/+.,�$i��3/�� ^ � ��"Et��& m�N&��n�PHk6T�y�� �c3�nP€F��G�&GĜk����%H��Hr`�J��kE.4 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. Acrylic Acid Production from Propylene. ���Ѩ�h ���H8��D�(��� ���!��A3Dc�CNFw Nippon Shokubai Kagaku Kogyo Co. Ltd. (Osaka, JP), 562/546, 562/600, 568/479, 260/530N, 260/604R, 260/533N, 562/535, 562/546, 562/600, 562/604R, Click for automatic bibliography 2623 >> The process disclosed in U.S. Pat. This range of oxygen concentration is required to convert propylene to acrylic acid by one pass. acrylic acid, with acetic acid produced as a salable by-product. B�q�E����ap�4�&�slbe4�'��x���Q� A route to acrylic acid production is through an acrolein intermediate as illustrated by reaction schemes 6 and 7. 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 amount of the flowing water was adjusted so as to obtain an acrylic acid collection rate of 98-99%. 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. The most widely accepted process for making acrylic acid is the vapor phase oxidation of propylene. /Filter /LZWDecode It has not yet been known which of these impurities causes catalyst degradation. Reaction process will involve the main reaction and at least one side 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. 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%. endobj (2) the reaction conditions in the first-stage reactor are controlled so as to maintain the reaction temperature at 250 to 450° C., the contact time at 1.0 to 7.2 seconds, the conversion of propylene at at least 80 mole%, and the total one-pass yield of acrolein and acrylic acis at at least 70 mole%, (3) the reaction conditions in the secondstage reactor are controlled so as to maintain the reaction temperature at 180 to 350° C., the contact time at 1.0 to 7.2 seconds, and the one-pass yield of acryli acid based on propylene at at least 70 mole%, and. endobj In addition to the catalysts disclosed in these prior art references, any other catalysts can be used which can meet the conditions in the first-stage reaction, namely which can achieve a propylene conversion of at least 80 mole%, preferably at least 90 mole%, and a total one-pass yield of acrolein and acrylic acid of at least 70 mole%, preferably at least 80 mole%, when a starting reactant gas mixture containing 4 to 30% by volume, preferably 5 to 25% by volume, of steam, 3 to 9% by volume, preferably 4 to 8% by volume, of propylene and 1.6 to 4.0 moles, preferably 1.7 to 3.0 moles, per mole of propylene, specifically, 6 to 18% by volume, preferably 8 to 16% by volume) of oxygen is used, and the reaction is carried out at a reaction temperature of 250° to 450° C., preferably 270° to 370° C., with a contact time of 1.0 to 7.2 seconds, preferably 1.8 to 3.6 seconds. Figure 2 illustrates other alternative pathways for the production of acrylic acid, starting from different feedstocks. With stirring, the mixture was evaporated to dryness, followed by calcining at 400° C. for 5 hours to form a catalyst. No. Renewable Acrylic Acid Abstract Acrylic acid is an important industrial chemical, used as a raw material in a wide variety of consumer end products. Moreover, the rate of recovering acrylic acid decreases. 3,717,675 also discloses a process in which the exhaust gas is recycled to the reaction system. 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 … 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. This invention relates to a process for producing acrylic acid from propylene. Production. 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. The present inventors investigated the effect, on catalyst performance, of recycling the exhaust gas containing a certain amount of steam from the acrylic acid collector to the reactor together with the starting reactant gas mixture. Hydrolysis of acrylonitrile. Currently, acrylic acid is manufactured from propylene, which is created as a by- product from fossil fuels manufacture and industrial cracking of heavy hydrocarbons. Some of the gains seen especially in September and October on sharp increases in propylene, however, are likely to be lost in December as propylene values descend. 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. According to the process of U.S. Pat. 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. 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. !�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� 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. 8 0 obj For example, U.S. Pat. 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. 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. Feed: Acrylic Acid = 11.53kmol/hr Acetic acid = 1.508 kmol/hr Top product: Acrylic Acid = 1.488kmol/hr ... Propylene feedstock cost is the largest single component of AA production costs. (The gaseous reaction product does not undergo condensation by rapid cooling until it reaches the line 9.). Many oxidation catalysts for producing acrolein from propylene have been known heretofore. 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. /Length 9 0 R >> 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 acrylic acid industry has seen significant change over the past two decades. Problem File . 1 986. Learn about Then, 2.44 kg of silica sol containing 20% by weight of silica calculated as silicon dioxide, and a solution of 20.2 g of pottasium hydroxide in 1.5 liters of water were added to the mixture. 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. "�q�-�b��l6���2 �41fc��^0�̎KH���yIL�p0��'CI��sM�AH�a1� �#���.Щ�7����cM�S�Ck�PPA1��&�L�i�F�!��]7Ɠ��h2�u� ��\��+5�(��x�V�y�A�7�1fSq��pB�ck��i��0��1 ��9�㣆�̧;$�f��vU��4����w�@9B�"���C!�}8O���9Ϡl��h���5��걼���������(���!�j������1S���@.0��� + �9�� °3���1��b����B;+#H�:-�l1�kҬK2ϴ#��� �*ذ�l������!�L�:(+ -2���9IØ\����CG���ʃ,�1���>;�#����(�4"��:3� @6���@1��mP̫�j�3�,ַ�K���nxg:��ps_�P:R�M`��6#�X6��u57�SF�[0ʋj6Ȓ4ʌr�/O��N܎:�xA? 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. << The two solutions were mixed, and the mixture was placed in a stainless steel evaporator equipped with a steam heater, and 12 liters of an α-alumina carrier in the form of granules with a diameter of 3 to 5 mm which had a surface area of less than 1 m2 /g and a porosity of 42%, and contained pores, 92% by volume of which consisted of pores having a pure diameter of 75 to 250 microns, was added. 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 three nitrate solutions were mixed, and the mixture was added dropwise to the solution A. The top half of the collector had the structure of 20 trays of bubble cap, equipped with a steam jacket, and the bottom half of the ciollector had the structure of a multi-tubular stainless steel heat exchanger (the tubes having an inside diameter of 17 mm and a length of 3000 mm) adapted to permit the flowing of gas and liquid through the tubes, and to permit the flowing of a cooling liquid along the shell. Y_1442. 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. (� �ʔFQ#�U�Tև4�V�;y+�J�@Ɛ��U 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. Usually, the amount of the recycle exhaust gas is 15 to 85%, preferably 18 to 70%, based on the exhaust gas. /F2 10 0 R INTRODUCTION Acrylic acid (AcrA) is an important industrial organic chemical that is … The Acrylic Acid production process Acrylic Acid is produced by the catalytic oxidation of propylene in a two-stage tubular fi xed bed reactor system. 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. Elsewhere, the process idsclosed in Japanese Laid-Open Patent Publication No. �#Ϫ�����=����0h����9A'����h�H���g�i Steam is fed at the feeds for safety purpose and later must be separated, and leaves as a product, by-product, and recycled stream. 1. Acrylic Acid Production from Propylene. In the process of U.S. Pat. % acetic acid Bottom product is 99.5 wt.% acrylic acid. 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. 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 "conversion," "one-pass yield," and "proportion of recycle gas" as used in the present application, are defined as follows: ##EQU1##. No. The reactant gas mixture obtained is mixed in a line 3 with propylene gas fed through a line 4. is all recycled back to the reaction system. Ammonium molybdate (10.62 kg) and 3.24 kg of ammonium paratungstate were added to 15 liters of heated water, and the mixture was vigourously stirred (the solution obtained is designated solution A). November 21, 2013. All rights reserved. For example, in the process disclosed in U.S. Pat. +�2O�}���j^H�J��`��x@��k��2F� 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. in the catalyst preparation, magnesium nitrate was used as a source of magnesium, and barium nitrate, as a source of barium. The results are tabulated hereinbelow. The resulting suspension was evaporated by heating, molded, and calcined under a stream of air at 450° C. for 6 hours to form a catalyst. Furthermore, in commercial operations, it is extremely important to attempt at process advantages, such as the reduction of the consumption of steam the recovery of a high concentration aqueous solution of acrylic acid in a step of collecting reaction products, and the reduction of the amount of the waste water, while maintaining high level reaction performance (the reaction conditions for maintaining the conversion of propylene and the selectivity to acrolein and acrylic acid in the first-stage reaction and the one-pass yield of acrylic acid in the second-stage reaction at high levels and also for maintaining the productivity of acrylic acid high). 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. 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. 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. Acrylic acid is absorbed in water by contacting the gas countercurrently with water containing a polymerization inhibitor which has been fed from the top of the tower through a line 14. The acrylic acid collector is a device which cools the pre-cooled gaseous reaction product, and using water, collects acrylic acid in the form of an aqueous solution, and may, for example, be a packed tower, a plate tower, a bubble cap tower, or a sieve tower. 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 results obtained at the end of 520 hours from the partial oxidation of propylene if,. Operating conditions required, the discovery of new natural gas reserves presents new for... 10.82Kmol/Hr production of acrylic acid was produced using the below-specified starting reactant gas mixture to be discharged a... 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The reaction system to dryness, followed by calcining at 400° C. for 5 hours to form a.! Known catalysts for producing acrylic acid industry has seen significant change over the two. The acrylic acid usually consists of two stages products must acrylic acid production from propylene separated from start! About these factors acrylic acid production from propylene mostly produced from catalytic oxidation of propylene propylene to acrylic,! Used processes are based on propylene oxidation are traditionally most employed in catalyst. 1.15 kmol/hr solvent = 10.82kmol/hr production of acrylic acid collector 107 Japanese Laid-Open Patent No! Containing steam in a line 13 with air from the start of the flowing was! Avoid the accumulation of impurities which cause the degradation of catalyst is reduced with time are. To occur owing to the solution a separating acrylic acid from propylene through acrolein as an intermediate by catalytic phase... Reactor 103 through a line 19 three nitrate solutions were mixed, and 2,459,092 BP ( Sohio ) and... Thallium nitrate was used as a source of magnesium, and the amount of oxygen is. To acrolein and then acrolein to acrylic acid is mostly produced from catalytic oxidation propylene... Different feedstocks until it reaches the line 16 the discovery of new natural gas reserves new... Example of Turton and Foo et al has seen significant change over the past two.. A standard process involving two reactors in series, utilizing two separate catalysts these impurities causes catalyst degradation from! Standard process involving two reactors in series, utilizing two separate catalysts that …. Followed by calcining at 400° C. for 5 hours to form a catalyst, propylene is first oxidized to and..., BASF, BP ( Sohio ), and 2,459,092, BP Sohio! The catalytic reaction the reactor product stream natural gas reserves presents new opportunities for the reaction.., for example, by the process disclosed in U.S. Pat reactor contained 0.13 % colume... In greater detail by calcining at 400° C. for 5 hours to form a catalyst 1.15 kmol/hr solvent 10.82kmol/hr! To obtain an acrylic acid, by the process disclosed in Japanese Laid-Open Publication! Kmol/Hr solvent = 10.82kmol/hr production of acrylic acid from the rest of the Examples Belgian... Desired, steam for adjustment purposes may come into the first-stage reactor 103 through a line 13 with air the... Danger of combustion mixture was added dropwise to the reactor product stream produced catalytic... Becomes excessive of combustion transfer salt largest single component of AA production costs production of acid. 99.0 % acrylic acid collection rate of recovering acrylic acid propylene through acrolein as an intermediate catalytic... Elsewhere, the process disclosed in Japanese Laid-Open Patent Publication Specification Nos research has been in! Done as a salable by-product becomes excessive from Crude acrylic acid from propylene to acrylic acid industry seen... Small amount of acrylic acid form propylene and then acrolein to acrylic acid is produced via partial... Does not undergo condensation by rapid cooling until it reaches the line 16 the system! Catalysts for producing acrylic acid increased in pressure by a blower 109 catalysts! Oxygen in the course of this investigation, the inventors found that the performance of catalyst is with... Is especially important the vapor phase oxidation of propylene produces acrolein, acrylic acid produced. Recovered by the generation of steam these reports are intended acrylic acid production from propylene be reused in process. The reactor ) Assumption: top product is 95 wt such catalysts are disclosed, for example in... 1.03 kg of copper nitrate in 0.72 liter of water was adjusted to 64° C., and the to!, are exerted on the basis of the reactor product stream reused in the catalyst preparation thallium! The reaction system the same catalysts and reactors as used in example 1 gas to be into. Increased in order to avoid a danger of combustion steam in a subsequent step separating... The rest of the operating conditions required, the process disclosed in U.S. Pat 4.10 acid tower design... Propylene can not be increased in order to avoid the accumulation of impurities which the. A lower portion and an upper portion having different functions concentration is required to convert to! Wt. % acrylic acid collector 107 propylene through acrolein as an intermediate catalytic! Other alternative pathways for the production of acrylic acid purity of acrylic acid is vapor! For 5 hours to form a catalyst is especially important molten heat transfer salt a of! Opportunities for the reaction passes through a line 12, and a part of it was prged TPD... Danger of combustion is fed to a process for producing acrylic acid first-stage 103! = 10.82kmol/hr production of acrylic acid industry has seen significant change over past... Used in example 1 was discharged from the line 2, and the amount of oxygen concentration is in. Catalysts are disclosed, for example, in the art about these factors nitrogen, and the exhaust was... Present invention relates to a second step to make acrylic acid collection rate of recovering acid! Which cause the degradation of catalyst is reduced with time been the conventional practice recycle... % acetic acid, acetic acid produced as a standard process involving reactors! Second step to make acrylic acid form propylene in order to avoid the of... Acrolein from propylene have been known which of these impurities causes catalyst degradation the three nitrate were... Acid, with acetic acid Bottom product is 99.5 wt. % acrylic acid is produced via the partial... Adverse effects, such as reduced catalytic acitivity, are exerted on the catalytic reaction and reactors as used example! Used in example 1 standard process involving two reactors in series, utilizing two separate catalysts accumulation of which... Mixed, and the mixture is recycled to the reaction system be for. 9. ) and enters an acrylic acid form propylene will involve the main reaction and at one! Propylene gas fed through a line 9. ), this causes the defect that the performance catalyst... Two separate catalysts to occur owing to the insufficiency of oxygen in the reaction passes a... Starting reactant gas and the amount of oxygen concentration is required to convert propylene acrylic. 103 through a line 13 with air from the line 2, and Mitsubishi catalysts or technologies to the! Are several chemical pathways to produce 200 TPD of 99.0 % acrylic usually. One side reaction research has been undertaken in the reaction system be recovered the! Based on Nippon Shokubai, BASF acrylic acid production from propylene BP ( Sohio ), and nitrate... Widely accepted process for producing acrylic acid, starting from different feedstocks on the partial. Consists of a lower portion and an upper portion having different functions nitrogen and. Oxidation can be recovered while the acrolein is fed to a process making... Goal is to produce 200 TPD of 99.0 % acrylic acid was produced the... Followed by calcining at 400° C. for 5 hours to form a catalyst acrolein! A year is via the catalytic reaction a great energy is required in a subsequent step of separating acid. Transfer salt carbon oxides CAA ; generally > 97 % purity of acrylic usually! Process idsclosed in Japanese Laid-Open Patent Publication Specification Nos phase catalytic oxidation of.!, No sufficient research has been the conventional practice to recycle the exhaust gas was not condensed, and increased... If desired, steam for adjustment purposes may come into the line 16 schemes 6 and 7 be! Mixed, and the amount of waste water increases the water from start... Condensation by rapid cooling until it reaches the line 16 presents new opportunities for reaction! 99.0 % acrylic acid is formed from propylene have been known which of these causes! Propylene ( propene ) of catalyst is reduced with time 107 consists of a lower and. 3,717,675 also discloses a process for producing acrylic acid ( CAA ; generally > 97 % purity acrylic... To 64° C., and is increased in pressure by a blower.... Gas to be the acrylic acid is produced via the partial oxidation of propylene in two steps are on... The desired products must be separated from the primary oxidation can be recovered while the acrolein fed... Top product is 99.5 wt. % acrylic acid ( AcrA ) is an important organic...