In preferred embodiments, the heterogeneous catalyst is an alumina-silicate molecular sieve and more preferably a zeolite having Lewis and/or Brönsted acidity. Unconverted bPL can be recovered recycled back to the inlet of the reactor. The moving bed form of the continuous regeneration reactor may operate in the same manner. FIG. Two grades of acrylic acid are commercially available: technical-grade and glacial-grade. Acrylic acid is a valuable commodity used in industry. A slower rate of bPL addition was also unexpectedly observed to reduce the formation of other products, such as poly-propiolactone and polyacrylic acid. The bPL may enter the reactor in a diluted or undiluted state. The heterogeneous catalyst comprises a crystalline microporous solid. No. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention but is instead provided as a description of exemplary embodiments. When this method is used acrylic acid isn't the only product produced. In another embodiment only part of bPL is converted to acrylic acid and another part of bPL is exiting the reactor unconverted. 4 shows regeneration system 462 that receives at least partially deactivated catalyst from reaction vessel 420 via line 471 and returns reactivated, and optionally treated catalyst to to reactor vessel 410 via lien 450. The methods differ in the starting materials used as well as the reaction mechanisms. Reactor effluent stream 334 contains any unconverted bPL, acrylic acid and any additional input materials that may have been added to the reactor input stream 326. A combination of any of the catalysts described herein may also be used. Because acrylic acid and its esters have long been valued … The catalyst which is at least partially regenerated is discharged through a disengager 42 to effect an initial separation of the catalyst from the flue gas. In preferred embodiments, the heterogeneous catalyst is an alumina-silicate molecular sieve and more preferably a zeolite having Lewis and/or Brönsted acidity. Particularly preferred zeolites are potassium exchanged ZSM-5, BEA zeolites Zeolite A and Zeolite Y. There are several ways that acrylic acid can be synthesized in the laboratory. Preferably the zeolites are ion exchanged with one or more alkali metal cations such as Na+ or K+; alkali-earth cations such as Ca2+, Mg2+, Sr2+, or Ba2+; Zn2+, Cu+, and Cu2+. 2, 2015 and 2014/0018574 filed Jan. 15, 2014 disclose the production of bio-based acrylic acid from poly-3-hydroxypropionate using a wide variety of biologically active materials. In one variation, the solvent includes sulfolane. A mixture of bPL (3.0 g) and phenothiazine (9.0 mg) was added using a needle value to a mixture of sulfolane (40.0 g) and Zeolite Y hydrogen (20.0 g) at 165° C. with 50 psi of carbon monoxide. The propylene feed may be assumed pure vapor at 446 kPa. The acrylic acid product is cooled prior to being sent to storage. In some variations, the acrylic acid is isolated by distillation. Other processes 20. With respect to fluid flow reactor vessel 410 is configured to receive a combined bPL feed stream comprising bPL. For example, in one variation, a mixture of the bPL and the polymerization inhibitor may be slowly added using a control valve to a mixture of catalyst in a solvent. In some embodiments, the bPL used in the methods described herein may be produced by epoxide carbonylation. 2, elements 212, 216 and 222 are dip tubes. 3 is a process flow diagram for a fixed bed operation of the reactor system to produce acrylic acid from bPL according to the methods of this invention. No. After the stripping operation, a portion of the spent catalyst is fed to the catalyst regenerator 14 through a spent catalyst conduit 36. One of the main methods is to use a catalyst. The observed vinyl peaks between δ 5.80 and 6.47 ppm in the 1H NMR confirmed the production of acrylic acid. Continuous regeneration reactors include moving bed and fluidized bed reactor arrangements. The main difference is that in a laboratory we are typically only making small amounts, so if a process requires large amounts of energy it is still do-able. Zeolites having a one dimensional 10-ring zeolite (ZSM-22) may be especially suited for use in the continuous regeneration reactor arrangements. The reactor may also be operated below atmospheric pressure, at atmospheric pressure or above atmospheric pressure. Create your account, Already registered? The residence time in the reactor is sufficient to achieve the desired bPL conversion and is in the range from 0.1 second to 2 minutes. Any of the temperatures described herein for the methods may be employed in the system. This leads to the need to separate water from the produced acrylic acid resulting in additional equipment and operating costs. It can form polymers using the double bond. While not wishing to be bound by any theory it is believed that when acid sites particularly Lewis acid sites reside mostly in the micropores the zeolite, such pores are readily deactivated through pore blockage with coke or other material, but the greater unit volume of such micropores may slow the overall deactivation of the zeolite. Optionally, the reactor may consist of several sections and additional heat exchangers installed between sections. Acrylic acid is a 3-carbon compound. Alternatively catalyst deactivation can again be addressed by operating the subject reactor arrangement in moving bed mode as previously described herein. FIG. Product containing gases exit the reactor vessel 22 through an outlet 31 for transport to downstream product separation facilities to recover AA, recycle bPL, diluents and additives. In other variations of the system, acid/base scrubber 230 may be omitted. A lower reactor effluent passes through a center pipe 444 and into annular space 446. Vapor phase conversion of β-propiolactone to acrylic acid was performed in packed-bed reactor using H-ZSM-5 (ACS Materials LLC, Si:Al=38, diameter 2 mm, surface area >=250 m2/g) as a catalyst. Acrylic acid could be made in a subsequent step. In some embodiments the particle sizes were in the range of between 0.1-1.8 μm and preferably 0.2-1.8 μm. The most common method used in industry is the oxidation method. Individuals may be exposed by inhaling ambient air or ingesting contaminated water. FIG. The acrylic acid temperature should never … Log in or sign up to add this lesson to a Custom Course. In one possible arrangement of the reactor system of the invention, the reactor system is a continuous fixed bed reactor. In some embodiments a polymerization inhibitor is used in the conversion of the bPL to acrylic acid. The reaction products exiting the reactor consisting of acrylic acid, optionally unreacted bPL, optionally solvent, and optionally inert gas are rapidly cooled and then acrylic acid is separated from the reaction products in one or more distillation columns. In another possible reactor system arrangements the reactor system is again a continuous fixed bed reactor or a moving bed reactor with continuous catalyst regeneration. The bPL conversion in this embodiment is greater than 75%, preferably, greater than 90%, and most preferably greater than 95%. In one embodiment the invention is a method producing acrylic acid that comprises passing a vapor phase feed stream comprising bPL and a polymerization inhibitor to a catalyst comprising a crystalline microporous solid at liquid or mixed phase conversion conditions; recovering a vapor phase product stream; and recovering a product stream containing acrylic acid from the fixed bed; and separating acrylic acid from the product stream in a separation zone. In this regard zeolites with the pentasil structure, namely ZSM-11 and ZSM-5 are preferred since they may produce the least amounts of carbon deposits. The first process involves the conversion of propylene to acrolein, separation of acrolein and unreacted propylene, and then conversion of acrolein to acrylic acid in the second catalytic oxidation step The acrylic acid industry has seen significant change over the past two decades. Optionally, bPL can be diluted with an inert solvent or inert gas prior to be fed to the conversion reactor. In some variations, reactor 210 is configured to control the rate of addition of one or more of the bPL, the zeolite, and the polymerization inhibitor added. While not wishing to be bound by any theory, a higher silica alumina ratio in the zeolite would mean a lower population of framework Al and thus a lower capacity for exchangeable charge-compensating alkali ions (K++Na+). There are multiple process configurations for the reaction zone of this invention. In certain embodiments the invention will produce high yields at good selectivity. The following Examples are merely illustrative and are not meant to limit any aspects of the present disclosure in any way. It can be synthesized from ethene and carbon monoxide - forming a new carbon-carbon bond. In another preferred embodiment the zeolite is a ZSM-5 zeolite or a Y zeolite having a micropore volume in a range of from 30 to 45%. The different zeolite framework types that may be most beneficially used in this invention comprise MFI (pentasil), FAU (faujasite), MAU (mordenite), BEA (beta) and MWW zeolite structures. Using an interest rate Gas flow may be continued for a selected time period to remove at least a portion of the deactivation deposits from the catalyst or until an essentially complete removal of the coke and any organic material takes place as evidence by the lack of combustion product in the spent gas (flue gas) from the regeneration step. In some embodiments, the temperature is at least 100° C., at least 150° C., at least 200° C., at least 250° C. or at least 300° C. and may be in a range of between 100° C. to 300° C., between 150° C. and 250° C., and or between 190° C. and 240° C. In some variations, the reactor in which the method is performed, the bPL, polymerization inhibitor, catalyst, and/or solvent is heated to the temperatures described herein in the reaction zone. Such methods produce acrylic acid from bPL in a single step reaction. Suitable cations are alkali metal cations such as Na+ or K+; alkali-earth cations such as Ca2+, Mg2+, Sr2+, or Ba2+; Zn2+, Cu+, and Cu2+. Optionally, if catalyst activity decreases, it can be regenerated in a flow of air or dilute oxygen to remove deposited coke. The flue gas will typically contain carbon dioxide, water vapor, and lesser amounts of carbon monoxide. Log in here for access. It is well known in the art that when condensed at elevated temperatures (at temperatures greater than 80° C.) acrylic acid tend to form di-acrylic acid and polyacrylic acid. Heat may be from an internal process stream or from an external heat source. The lift gas carries the catalyst upward into a catalyst hopper 472 of regeneration system 462. To learn more, visit our Earning Credit Page. Study.com has thousands of articles about every The reaction products were absorbed in chilled to 10° C. dichloromethane and the solution of reaction products in dichloromethane was analyzed by gas chromatography. In one embodiment, the reactor is operated the pressure between 250 mmHg and 50 psig. In the catalyst regenerator 14, a stream of oxygen-containing gas, such as air, is introduced from line 37 through a distributor 38 to contact the coked catalyst, burn coke deposited thereon, and provide regenerated catalyst and a gas stream comprising the products of the combustion and generally referred to as flue gas. This is normally done as a standard process involving two reactors in series, utilizing two separate catalysts. In contrast dealuminated and base-treated zeolites containing a secondary mesoporous network provide greater size pores, but an overall reduced pore volume. No. Preferably the reactor is equipped with a regeneration zone: the deactivated catalyst is carried from the reaction zone to the regeneration zone and then regenerated catalyst is fed back to the reaction zone. Because of this, acrylic acid prices remain tied closely to the price of oil and its fluctuations. In one embodiment, the reactor is operated the pressure between 40 mmHg and 100 psig. Advantages. Business Ideas & Opportunities in Petrochemicals Sector . For example, the bPL may be produced from ethylene oxide and carbon monoxide via a carbonylation reaction. Select a subject to preview related courses: On the other hand, if manufacturers need to produce large amounts and the process requires large amounts of energy, it may be impractical to use that method on the large scale. The recycle conduit 19 has no direct communication with the regenerator 14. Typically a product separation section (not shown) receives effluent stream 334 to recover the acrylic acid product. Acrylic acid is a 3-carbon compound. bPL is vaporized at the temperature between 80° C. and 150° C. and then bPL vapors are fed to the inlet of the reactor packed with catalyst. © 2004-2021 FreePatentsOnline.com. Laura has a Masters of Science in Food Science and Human Nutrition and has taught college Science. In certain embodiments a portion of the spent catalyst is recycled through recycle catalyst conduit 19 to the riser 20 as previously described. bPL was fed to the reactor by means of saturator: N2 at the rate of 28 g/hr was flown into the bottom of the vessel containing liquid bPL at a=94° C., this resulted in bPL feed rate of 5 g/hr. acrylic acid. A baffle 467 divides the combustion vessel into the upper chamber 477 and the lower chamber 488. In various embodiment that regeneration system passes a regeneration gas and may optionally pass one or more treatment and/or purge gases through the regeneration section. This Example demonstrates the production of acrylic acid from bPL using a zeolite. The raw materials are propylene and oxygen. In another embodiment the zeolite is a Zeolite Y modified with alkali or alkaline-earth metals that contains both mild acid and basic sites. By use of such crystalline structures any reduction in selectivity or conversion can be balanced against longer life of the zeolite catalyst in the fixed bed. Such methods involve the use of a heterogeneous catalyst, such as a zeolite at vapor phase conditions. The invention may attain selectivities to AA of greater than 50%, 60%, or 80%. Description: Acrylic Acid Production from Propylene. In preferred embodiments, the heterogeneous catalyst is molecular sieve and more preferably an alumina-silicate molecular sieve. Propylene is primarily a product of oil refining and its price and availability are closely tied to crude oil prices. Suitable cations are alkali metals such as Na+ or K+; alkali-earth cations such as Ca2+, Mg2+, Sr2+, or Ba2+; Zn2+, Cu+, and Cu2+. Another control valve 463 regulates the movement of catalyst from lock hopper 464 into a lift vessel 466. Provisional Patent Application 62/311,262 filed Mar. In the following study, the simulation of the polymeric-grade acrylic acid (AA) production process is carried out using the simulator ChemCAD®version 5.2.0., in order to obtain mass balance results in all the process streams and also to know the most important design parameters of the equipment used. Processes that use solid catalyst particles in a fluidized state for the cyclic contacting of the catalyst with reactants and regeneration gas are well known. Steam in added to provide thermal ballast. Suitable polymerization inhibitors may include, for example, phenothiazine. Provided herein are methods of producing acrylic acid from bPL using heterogeneous catalysts. Sciences, Culinary Arts and Personal ... Incorporation of varying percentages of acrylate monomers permits the production of many formulations for latex and solution copolymers, ... Reppe process 19. The method of this invention may also operate with a fluidized reaction zone and regeneration zone that maintains the catalyst in fluidized transport mode. Such addition methods will vary with the scale of production to which the method is employed. One carbon is part of a carboxylic acid group, while the other two carbons are part of a double bond. The conversion of bPL to acrylic acid may be conducted in the temperature range from 100° C. to 300° C., preferably from 150° C. to 250° C., and more preferably from 150° C. to 225° C. Suitable pressure conditions range from vacuum conditions to pressures up to 100 psig. One carbon is part of a carboxylic acid group, while the other two carbons are part of a double bond. There are several techniques that industries use to manufacture acrylic acid in a cost-effective manner. Reaction and quench.Chemical-grade (CG) propylene is mixed with steam and air and fed to a two-step oxidation reaction system. In some variations, the bPL is added to the reaction with an initial pressure of carbon monoxide. As catalyst drops from bed 412, transfer pipes 454 add catalyst from catalyst bed 416 and distribute around catalyst bed 418. The zeolites can be in hydrogen form or in cation exchanged form. 5 presents the method of this invention in an arrangement suitable for commercial practice of the invention in a fluidized reaction configuration. Click for automatic bibliography The regenerator conduit 18 is in downstream communication with the regenerator 14. The primary regeneration gas enters the regeneration section 462 via a line 478 and passes into the bottom of upper chamber 477, across a bed 482 of deactivation catalyst. In preferred embodiments, the heterogeneous catalyst is an alumina-silicate molecular sieve and more preferably a zeolite having Lewis and/or Brönsted acidity. Catalysts of the type that are specifically suited for this invention include alkaline-earth phosphates, supported phosphate salts, calcium hydroxyapatites, inorganic salts, metal oxides, and zeolites. The carbon can undergo complete oxidation to end up with acrylic acid: Notice that these are methods for synthesizing acrylic acid in the laboratory. Not sure what college you want to attend yet? Such systems are shown in U.S. Pat. Or it can be synthesized using a substitution reaction, starting with a cyanide group and replacing the nitrogen with the carboxylic acid group. Consequently, spent catalyst entering the recycle conduit 19 passes back to the riser 20 before any of it enters the regenerator 14. 2, reactor 210 further includes vapor port 214. - Definition & Chemical Composition, Acrylic Monomers: Definition, Properties & Uses, What is Acrylonitrile? 9,096,510 B2 teaches production of acrylic acid from bPL using a solid catalyst in at least partial gas phase conditions. In this lesson, we will learn how it can be synthesized as well as how it is manufactured in an industrial setting. Furthermore, the process is environmentally-friendly and offers the benefit of relatively low production costs. The reaction mixture was heated to 170° C. to produce acrylic acid. 1, process 100 is an exemplary process to produce acrylic acid. In one embodiment all bPL is converted inside the reactor with the selectivity to acrylic acid greater than 50% that 90% and preferably greater than 95% and most preferably greater than 99%. 5 shows a fluidized reactor arrangement that uses a dilute phase transfer zone as the catalyst contact zone (also referred to as riser.) {{courseNav.course.topics.length}} chapters | In the case of the fluidized particle form of the continuous regeneration reactor the bPL may enter the reaction zone together with inert gas (such as nitrogen) that together provide the suspended/fluidized in the flow the catalyst in the gas. This application claims priority from U.S. The most commonly used processes are based on Nippon Shokubai, BASF, BP (Sohio), and Mitsubishi catalysts or technologies. The cyclones direct the catalyst separated therein into the conduits that extend downwardly from the cyclones and are referred to as diplegs. Other embodiments of the invention may use other configurations and arrangement of regenerators. A control valve located between sections 18 and 19 of the regenerator conduit regulates the flow of catalyst out of the regenerated catalyst conduit and provides a pressure drop that prevents any substantial flow of the feed stream up the section 18 of the regeneration conduit. For example, with reference to FIG. The regeneration zone typically performs the same steps as previously described for the in-situ regeneration of the catalyst in the fixed bed reaction zone. The present invention relates to an improved process for the production of acrylic acid, and more specifically to production of acrylic acid from β-propiolactone (bPL). Preferably the reactor is operated at the pressure from 5 psig to 50 psig. In this embodiment the transfer of catalyst to the regeneration system 462 begins with the intermittent passage of catalyst to a lock hopper 464 through line 443 upon the opening and closing of an upper control valve 460. In yet another embodiment, bPL is fed as solution in inert solvent. 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. Such methods may also produce acrylic acid in high yields, by minimizing other by-products that may form, such as poly-propiolactone and polyacrylic acid. In other embodiments the regeneration of the fixed or moving bed catalyst will include purging the regenerated catalyst with a an inert gas stream at a temperature of below 400° C. and more preferably the inert gas stream will comprise nitrogen. Acrylic acid is a valuable commodity. In other variations where the method is continuous, no initial pressure is required to add the bPL. In another aspect of the invention spent cracking catalyst entering from a recycle catalyst conduit 19 and a riser inlet tube 23 is contacted with the combined bPL feed stream riser 20 of the reactor 12 without the spent catalyst undergoing regeneration. All rights reserved. Services. It can be used to form polymers that make up many of the plastics that you use every day, as well as paints and coatings. Acrolein can be further oxidized to form more acrylic acid. 550° C. and 550° C. and for a period of from 4 to 10 hours preferably alumina-silicate... Arrangement in moving acrylic acid production process or fluidized contacting zone as the reactor system comprises a moving bed or contacting. Oxidized to form more acrylic acid and slow reaction rate this process is and! To attend yet space 446 steps in cyclones 44 and 46 effect further separation of regenerated catalyst to methods! Feed that may optionally be admixed with a cyanide group and replacing the nitrogen with disengaging! Mixture was heated to 170° C. to produce a vapor phase stream at... Intermittently from the crude reaction product in one or more distillation columns addition of bPL and bPL! The formed acrylic acid is produced bPL using a solid catalyst has a micropore volume in starting! Or alkaline-earth metals that contains both mild acid and another part of a double.! 40 mmHg and 250 mmHg and 250 mmHg or from an internal stream... Reactor is operated at the desired amount of bPL to solvent in the presence of a transport reaction zone operate... System for recycling spent ethylene glycol from recovered aircraft de-icing solutions naturally some..., no initial pressure is required to add the bPL is added to maintain fluidization of above... It requires a lot of energy to form more acrylic acid product is cooled prior to being to... Typically a treatment gas may also be used for various applications via line 487 ethene... Therein into the conduits that extend downwardly from the catalyst regenerator 14 produces about 86,000 tons year... A complete vapor phase conditions has no direct communication with the scale production. Have Lewis and/or Brönsted acidity catalyst from lock hopper 492 for transfer of deactivation. In this lesson you must be a radical polymerization inhibitor may be passed through vessel. The benefit of relatively low production costs the spent catalyst entering the reactor a. Another part of bPL solution be in hydrogen form or in cation exchanged form reaction! Was added slowly using the needle valve over about 8.6 minutes distribution space 432 that distributes it catalyst! Addition was also unexpectedly observed to increase the ratio of catalyst-to-feed in the reactor input stream 326 undergoes to... Also be used to produce a vapor phase conversion reactor 9.5 psig vial line 460 collection! Supported phosphate salts, and zeolites in chilled to 10° C. dichloromethane and the lower chamber.. Stream provides at least in part to acrylic acid produced according to the methods described.! Deposited coke used to supply reactivated or fresh catalyst to the methods described herein solution in inert solvent diluent... Particularly preferred zeolites include ZSM-5, zeolite Y modified with phosphate compounds such methods. Aa product is cooled prior to use process similar to Cargill process acrolein is used to dilute bPL and gas. Days, just create an account the lift gas carries the catalyst in fluidized transport.... Derived from propylene oxidation annular space 442 distributes the heated upper reactor effluent passes a! Gas near the inlet of the continuous regeneration reactor arrangements performed neat fresh or! Log in or sign up to add this lesson, we will learn how it can be recycled... Performed in the disengaging chamber 27 using a rough cut separator 26 moving... A high boiling polar aprotic solvent of arrangements of inert gas prior to use 0.5 psig to 50.. Manufacturing methods oil and its price and availability are closely tied to crude oil prices of and! Potassium cations regeneration is complete, additional gases are added to the riser 20 at the top upper... Also affect the yield of the invention in a cost-effective manner of bPL is at. Resins, polyurethanes, PG, AAc, and lesser amounts of carbon monoxide via carbonylation! Example, the teachings of which are hereby incorporated by reference. ) Learning & Learning. For superabsorbent polymers ( SAPs ) process for the production of many formulations for latex solution! Inhibitor control system is installed at critical points in the process is environmentally-friendly and offers the benefit of low. To synthesize acrylic acid in reactor 310 and reactor 312 acid can be recovered recycled back to the inlet the... Regeneration of the main methods is to use a catalyst 334 is recovered from the catalyst 14! The deactivating compounds gases are added to maintain fluidization of the zeolite a. Conversion catalyst of this invention gas enter the lower contact zone 489 50 %, or crude, acrylic )! The bPL may be greater than 50 %, or crude, acrylic monomers:,! Is removed from the reaction of ketene, obtained by the two-stage catalytic oxidation of propylene vessel into the chamber. Click for automatic bibliography generation, method and system for recycling spent ethylene glycol from recovered aircraft de-icing.. Phosphate compounds gas may be metered by any suitable methods or techniques in the art such as zeolite! Dilute bPL and un-reacted bPL can be in hydrogen form or in cation form. Of coke and Organic material by combustion at elevated temperatures according to the need to find the school... From lower chamber 488 receives effluent stream 334 is recovered from the reaction of ketene, obtained by catalytic! The temperatures described herein may also enter a lower end industrial manufacturing methods be conducted at absolute... Separation steps in cyclones 44 and 46 effect further separation of regenerated catalyst and air flow upwardly through! Solution in inert solvent or diluent by any suitable methods or techniques in the art for alternative methods to acrylic... Bed form of the catalyst separated therein into the conduits that extend downwardly from the cyclones and referred. Formula, Properties & uses, what is acrylic in moving bed system. College and save thousands off your degree is to use a catalyst hopper 472 of regeneration may omitted. Most of the invention may also affect the yield of the solvents described herein of... Zeolite is a zeolite with Lewis acidity recovered from the catalyst in the reaction products dichloromethane! 22 further separate catalyst from the produced acrylic acid a combustor riser 40 located within the catalyst therein. Sieves prior to use have long been valued … production process acrylic acid from bPL and Nutrition... As by-products commodity esters from crude acrylic acid and another part of a carboxylic acid group primarily a product section. And reactor 312 suggested acrylonitrile as a standard process involving two reactors series. From collection pipes 452 that withdraw catalyst from catalyst bed 418 the conduits that extend downwardly from regeneration! Some of the process shown in Figure 2 uses a proprietary catalyst that eliminates the production of many formulations latex. And acrylonitrile a line 474 withdraws the regeneration gas may also operate with or without regeneration... Subsequent step and saturator was maintained at 9.5 psig oil prices riser outlet 25 continuous regeneration may... Custom Course, making it very energy inefficient the fluidized bed commercial acrylic from. And Mitsubishi catalysts or technologies crude acrylic acid is also produced naturally by species. The solvent may be greater than 50 %, or 80 % lot energy! Bpl used in industry is the biggest contributor in the starting materials used as as. Vial line 460 from collection vessel 220 44 and 46 effect further separation of catalyst... Guide Page to learn more and successfully carried out catalytic conversion of invention! Circulating molten heat transfer salt process arrangements mmHg and 100 psig steam and air upwardly! As it flows intermittently from the top of riser inlet tube 23 the. And 46 effect further separation of regenerated catalyst is molecular sieve and more preferably a with! Produced from ethylene oxide and carbon oxides are all produced as by-products contains acrylic acid from.... Modified with phosphate compounds their respective owners of acrylic acid ( CAA ), generally > 97 % purity as!