Abstract: The invention relates to the production of (meth)acrylic esters according to a process by direct esterification, and in particular to the purification of a crude reaction mixture comprising a C4-C12 (meth)acrylic ester using a dividing wall column employed in a particular configuration. The dividing wall column is equipped with a separating wall creating separation zones in the column, the wall not being joined to the upper dome of the column in the top part and being joined to the bottom of the column in the bottom part. The process according to the invention guarantees a product of very high purity, independently of the back-cracking reactions of the heavy by-products liable to arise during the purification of the product sought.

Abstract: An isopoly-molybdic acid coordination polymer catalyst for manufacturing polycaprolactone and method of manufacturing the same are provided. It relates to a field of catalysts from polycaprolactone. The chemical formula of the isopoly-molybdic acid coordination polymer catalyst is [Cu2(trz)2(?-Mo8O26)0.5(H2O)2]. In the chemical formula, trz is 1,2,4-triazole negative monovalent anion, and [?-Mo8O26] is a ? type octamolybdate anion. This synthesis method offers higher yield with strong reproducibility. The resulting crystal products have higher purity. The isopoly-molybdic acid coordination polymer catalyst shows high catalytic activity towards the bulk ring-opening polymerization of caprolactone. The resulting polycaprolactone has a weight average molecular weight exceeding 50,000 and a narrow molecular distribution. The polycaprolactone has great potential in the application of low- to medium-temperature thermoplastic medical materials.

Abstract: A method for producing an oxide catalyst according to the present invention is a method for producing an oxide catalyst containing Mo, V, Sb, and Nb, the method including: a raw material preparation step of obtaining an aqueous mixed liquid containing Mo, V, Sb, and Nb; an aging step of subjecting the aqueous mixed liquid to aging at more than 30° C.

Abstract: A method for producing (meth)acrylic acid comprising: a step of obtaining a (meth)acrylic acid-containing gas by subjecting a (meth)acrylic acid production raw material to a catalytic gas phase oxidation reaction; a step of obtaining a (meth)acrylic acid-containing liquid by bringing the (meth)acrylic acid-containing gas into contact with a collection solvent and/or condensing the (meth)acrylic acid-containing gas by cooling; a step of obtaining crude (meth)acrylic acid by introducing the (meth)acrylic acid-containing liquid into a low-boiling separation column; a step of obtaining purified (meth)acrylic acid and a refining residue containing a glyoxal compound by purifying the crude (meth)acrylic acid; and a step of returning at least a part of the refining residue to the low-boiling separation column; wherein a returning position of the refining residue to the low-boiling separation column is located closer to a bottom side of the low-boiling separation column than a supply port of the (meth)acrylic acid-co

Abstract: The invention relates to the use of a column with a separating wall as a purification/finishing column in a (meth)acrylic acid recovery method based on the use of two distillation columns in the absence of external organic solvent. The method according to the invention improves the energy balance for the method while improving the technical quality of the (meth)acrylic acid recovered. The method according to the invention further produces polymer-grade (or glacial) (meth)acrylic acid compatible with the production of high-molecular weight acrylic acid polymers.

Abstract: A process for isolating pure tert-butyl (meth)acrylate from crude tert-butyl (meth)acrylate by distillation, wherein the process is carried out in a dividing wall column having separation-active internals and a vaporizer and in which a dividing wall is arranged in the longitudinal direction of the column to form an upper joint column region, a lower joint column region, an inflow section having a side feed point, and an offtake section having a side offtake point, where the column has from 20-80 theoretical plates and the ratio of the amount of liquid at the upper end of the dividing wall going to the enrichment section and the stripping section of the column is set in the range from 1:0.2 to 1:5.

Abstract: A method of preparing (meth)acrylic acid by using a reaction distillation apparatus including a reaction distillation tower, and a natural circulation type of heat exchanger as a heat source for the reaction distillation tower. The reaction distillation tower a vessel, where decomposition of Michael adducts occurs, connected to a distillation tower, where distillation of decomposition products occurs. The method includes the following steps: feeding a waste liquid to the reaction distillation apparatus after passing through the heat exchanger, wherein the waste liquid is fed to a lower portion of the heat exchanger via a first input port; feeding a gas, separately from the waste liquid via a second input port, to the lower portion of the heat exchanger, and producing and recovering (meth)acrylic acid while the waste liquid is circulated in the reaction distillation apparatus by the gas which is fed separately from the waste liquid.

Abstract: An ?,?-unsaturated aldehyde and/or an ?,?-unsaturated carboxylic acid are prepared by gas phase oxidation of alkene with molecular oxygen over a fixed catalyst bed comprising a bed of hollow cylindrical shaped catalyst bodies having a multimetal oxide active composition. The fixed catalyst bed comprises at least three successive reaction zones; the highest local temperature in the fixed catalyst bed does not occur in the reaction zone closest to the reactor outlet; the highest local temperature in the fixed catalyst bed does not occur in the reaction zone closest to the reactor inlet; and the value WT=(ED?ID)/2 in the reaction zone in which the highest local temperature in the fixed catalyst bed occurs is lower than in the other reaction zones, in which ED is the external diameter and ID is the internal diameter of the shaped catalyst body. The yield of the products of value is enhanced in this way.

Abstract: This invention provides a method for producing acrolein and/or acrylic acid by catalytic gas-phase oxidation, which method makes it possible to carry out a continuous operation steadily for a long period of time while a high yield is maintained. This method is characterized by comprising filling each of reaction tubes of a fixed-bed multitubular reactor with at least two species of catalysts each of which essentially comprises, as catalytically active components, oxide of molybdenum, oxide of bismuth and oxide of iron and/or composite oxide of at least two of said elements, said at least two species of catalysts being different in the ratio of D1/D2, D1 denoting the proportion of the total pore volume of pores whose pore diameter falls within the range of at least 0.03 ?m and less than 0.3 ?m to the total pore volume of the whole pores, and D2 denoting the proportion of the total pore volume of pores whose pore diameter falls within the range of at least 0.

Abstract: There is provided a process for producing a shaped catalyst for a fixed bed oxidation reaction or a fixed bed oxidative dehydrogenation reaction, the catalyst having both of sufficient mechanical strength and catalyst performance, and the catalyst is produced by supporting a catalyst powder containing a complex metal oxide having molybdenum as an essential ingredient on an inert support by a tumbling granulation method at a relative centrifugal force of 1 to 35G.

Abstract: The disclosed invention is a method for manufacturing an oxidized organic compound which includes a step of forming an oxidized organic compound, in use of a fixed-bed reactor having a reaction tube packed with an oxide catalyst, by supplying at least one type of organic compound as a reaction feedstock gas and using a molecular oxygen-containing gas to carry out a catalytic gas-phase oxidation reaction; and a step of stopping the catalytic gas-phase oxidation reaction. In the manufacturing method, when stopping the catalytic gas-phase oxidation reaction, the supply of the reaction feedstock gas is stopped, after which an inert gas is supplied to the reactor, then a molecular oxygen-containing gas is supplied, subsequent to which the supply of the molecular oxygen-containing gas to the reactor is stopped.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of acids from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of acids in the hydrocarbon stream by use of adsorbents or basic solutions.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: The present invention relates to a process for preparing unsaturated aldehydes or unsaturated carboxylic acids by heterogeneous catalytic gas phase oxidation of unsaturated or saturated hydrocarbons, comprising the process steps of: i) providing a gas mixture comprising a saturated hydrocarbon and catalytically dehydrogenating the saturated hydrocarbon in the gas phase to obtain a gas mixture comprising an unsaturated hydrocarbon in a dehydrogenation reactor having a dehydrogenation catalyst material; or ii) providing a gas mixture comprising oxygen and an unsaturated hydrocarbon; iii) catalytically oxidizing the unsaturated hydrocarbon obtained in process step i) or provided in process step ii) in the gas phase to obtain a gas mixture comprising an unsaturated aldehyde in a first oxidation reactor having a first oxidation catalyst material; wherein at least one of the reactors selected from the dehydrogenation reactor, the first oxidation reactor and the second oxidation reactor comprises at least one foam b

Abstract: The present invention relates to a method and apparatus for continuous recovery of (meth)acrylic acid, and more specifically to a method of continuous recovery of (meth)acrylic acid, including: conducting gas phase oxidation of at least one compound selected from the group consisting of propane, propylene, butane, i-butylene, t-butylene, and (meth)acrolein in the presence of a catalyst to obtain a mixed gas containing (meth)acrylic acid; quenching the (meth)acrylic acid-containing mixed gas to remove high boiling point by-products in the (meth)acrylic acid-containing mixed gas; contacting the high boiling point by-product-free (meth)acrylic acid-containing mixed gas with water or an aqueous solution to obtain an aqueous solution containing (meth)acrylic acid; and purifying the aqueous solution containing (meth)acrylic acid to obtain (meth)acrylic acid.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of heavy metals from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of heavy metals in the hydrocarbon stream.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of mercury from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of mercury and mercury containing compounds in the hydrocarbon stream.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of solids from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of inorganic and organic solids in the hydrocarbon stream by use of adsorbent beds, filters, cyclone or gravity separators.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of organic oxygenates from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of organic oxygenates in the hydrocarbon stream.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of acids from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of acids in the hydrocarbon stream by use of adsorbents or basic solutions.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes removing at least a portion of heavy hydrocarbon compounds including C2+ hydrocarbons from a hydrocarbon stream. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level heavy hydrocarbons in the hydrocarbon stream by use of adsorbents, physical separators or cryogenic separation.

Abstract: Methods and systems are provided for converting methane in a feed stream to acetylene. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of water, carbon dioxide and other condensable contaminants in the hydrocarbon stream by use of a fluid separation assembly such as a supersonic inertia separator. In addition, one or more adsorbent beds may be used to remove remaining trace amounts of condensable contaminants. The fluid separation assembly has a cyclonic fluid separator with a tubular throat portion arranged between a converging fluid inlet section and a diverging fluid outlet section and a swirl creating device.

Abstract: The invention relates to a shaped catalyst body for the catalytic conversion of organic and inorganic components in fixed-bed reactors, wherein the shaped catalyst body is formed as cylinder with a base, a cylinder surface, a cylinder axis and at least one continuous opening running parallel to the cylinder axis, and the base of the cylinder has at least four corners.

Abstract: The present invention relates to a method and apparatus for continuous recovery of (meth)acrylic acid, and more specifically to a method of continuous recovery of (meth)acrylic acid, including: conducting gas phase oxidation of at least one compound selected from the group consisting of propane, propylene, butane, i-butylene, t-butylene, and (meth)acrolein in the presence of a catalyst to obtain a mixed gas containing (meth)acrylic acid; quenching the (meth)acrylic acid-containing mixed gas to remove high boiling point by-products in the (meth)acrylic acid-containing mixed gas; contacting the high boiling point by-product-free (meth)acrylic acid-containing mixed gas with water or an aqueous solution to obtain an aqueous solution containing (meth)acrylic acid; and purifying the aqueous solution containing (meth)acrylic acid to obtain (meth)acrylic acid.

Abstract: There is provided a process for producing aerolein, acrylic acid, methacrolein, methacrylic acid in a safe and steady manner and in high yields, which avoids a phenomenon of occurrence of an abnormal reaction attributable to the fact that the temperature at a raw material gas outlet side becomes considerably higher than the temperature at a raw material gas inlet side, with regard to the temperature of a catalyst packed in a reaction tube at vapor-phase catalytic oxidation of propylene, isobutylene, or the like.

Abstract: The present disclosure relates to a single shell open interstage reactor (“SSOI”). The SSOI comprises a first reaction stage, an interstage heat exchanger, an open interstage region, and a second reaction stage. The SSOI may be configured for upflow or downflow operation. Further, the open interstage region of the SSOI may comprise a supplemental oxidant feed. When the open interstage region comprises a supplemental oxidant feed, the SSOI may further comprise a supplemental oxidant mixing assembly. Processes for producing acrylic acid through the oxidation of propylene are also disclosed.

Abstract: The process for the distillation of a gas mixture comprising (meth)acrylic acid obtained from the gas-phase oxidation of at least one (meth)acrylic acid precursors is improved through the use of coupled distillation columns. In a first column, the gaseous mixture is dehydrated while in a second column, the dehydrated gaseous mixture is distilled into product, overhead and bottoms streams.

Abstract: A process for inhibiting polymerization of (meth)acrylic acid and/or (meth)acrylic esters by introducing an oxygenous gas into the (meth)acrylic acid and/or the (meth)acrylic ester, in which the (meth)acrylic acid and/or the (meth)acrylic ester has a degree of purity of at least 95% and is in the liquid state.

Abstract: A process for producing a ringlike oxidic shaped body by mechanically compacting a pulverulent aggregate introduced into the fill chamber of a die, wherein the outer face of the resulting compact corresponds to that of a frustocone.

Abstract: The invention relates to a process of the selective oxidation of carbon monoxide to carbon dioxide present in a gas mixture comprising at least one hydrocarbon or a hydrocarbon derivative, and to its integration into a process for producing hydrocarbon derivatives. The process according to the invention comprises a step that consists in bringing said gas mixture into contact with a solid catalyst capable of oxidizing carbon monoxide to carbon dioxide at a chosen temperature, characterized on that said step is carried out in a fluidized bed.

Abstract: The present invention relates to a process for preparation of pure methacrylic acid, at least comprising the process steps: a) gas phase oxidation of a C4 compound to obtain a methacrylic acid-comprising gas phase, b) condensation of the methacrylic acid-comprising gas phase to obtain an aqueous methacrylic acid solution, c) separation of at least a part of the methacrylic acid from the aqueous methacrylic acid solution to obtain at least one crude methacrylic acid-comprising product; d) separation of at least a part of the methacrylic acid from the at least one crude methacrylic acid-comprising product by means of a thermal separation process to obtain a pure methacrylic acid.

Abstract: In industrial scale production of acrolen and/or acrylic acid by catalytic gas-phase oxidation of propylene or a propylene-containing gas with molecular oxygen or a molecular oxygen-containing gas or in industrial scale production of acrylic acid by catalytic gas-phase oxidation of acrolein or an acrolein-containing gas with molecular oxygen or a molecular oxygen-containing gas, this invention provides a process characterized in that the initial stage operation is carried out under advancedly elevated reaction temperature and thereafter the reaction temperature is lowered to carry out the steady state operation. According to this process, acrolein and/or acrylic acid can be produced in high yield stably over prolonged period.

Abstract: A process which enables production of acrylic acid on an industrial scale at high productivity with stability, comprising production of acrylic acid by oxidation of propane with molecular oxygen, is provided. The process is characterized in characterized by re-use of the gas containing unreacted propane, as obtained after recovering acrylic acid from the gas produced of the reaction, as a recycling gas after removing at least a part of carbon dioxide from the same gas.

Abstract: The invention relates to processes for production of methacrylic acid and to processes for production of methyl methacrylate.

Abstract: A system and process for separating methacrolein (MA) from methacrylic acid (MAA) and acetic acid in the gas phase product from partial oxidation of isobutylene (IB) in two oxidation steps is disclosed. The process and system maximize recovery of all three components at minimum capital and energy cost, under conditions that minimize polymerization conditions and plugging by solids deposition in compressors, columns, etc.

Abstract: The invention relates to a method for preparing acrylic acid from an aqueous glycerol solution, comprising a first step of dehydration of the glycerol to acrolein, carried out in the gas phase in the presence of a catalyst and under a pressure of between 1 and 5 bar, and a second step of oxidation of the acrolein to acrylic acid, in which an intermediate step is implemented, consisting in at least partly condensing the water and heavy by-products present in the stream issuing from the first dehydration step. This method serves to obtain high acrylic acid productivity and selectivity.

Abstract: A process for the long-term operation of a heterogeneously catalyzed partial gas phase oxidation of an organic starting compound, in which the reaction gas input mixture is partially oxidized over a fixed catalyst bed which is accommodated in two successive temperature zones A, B whose temperature is changed with increasing operating time such that the initially lower temperature increases and the difference between the two temperatures decreases.

Abstract: Disclosed is a method of a gas-phase catalytic oxidation reaction of propylene, isobutylene, or tertiary butanol with molecular oxygen in the presence of a catalyst to produce a corresponding unsaturated aldehyde and a corresponding unsaturated carboxylic acid, in which the catalyst can be used over a long period of time. Concretely, in the presence of the catalyst containing a complex oxide including molybdenum, bismuth and iron as essential components, at least one factor of a reaction pressure and a molar ratio of molecular oxygen to a raw material is controlled to change in such a way that a rate of reaction of the raw material is kept constant in the temperature range of from (TA?15)° C. to TA° C., when a boundary temperature of the activation energy of the catalyst is set to be TA° C.

Abstract: Disclosed is a method for producing at least one of an ?,?-unsaturated aldehyde and an ?,?-unsaturated carboxylic acid from an alcohol in a liquid phase through a simple process. Namely, at least one of an ?,?-unsaturated aldehyde and an ?,?-unsaturated carboxylic acid is produced by dehydrating and oxidizing an alcohol in a liquid phase at 110 to 250° C. in the presence of molecular oxygen and a noble metal-containing catalyst. Alternatively, at least one of an ?,?-unsaturated aldehyde and an ?,?-unsaturated carboxylic acid is produced by dehydrating and oxidizing an alcohol in a liquid phase in the presence of molecular oxygen, a noble metal-containing catalyst, and an acidic substance.

Abstract: Disclosed is a shell-and-tube heat exchanger type reactor that can be used for a process of producing unsaturated acids from olefins via fixed-bed catalytic partial oxidation, which comprises at least one reaction tube, each including at least one first-step catalyst layer, in which olefins are oxidized by a first-step catalyst to mainly produce unsaturated aldehydes, and at least two second-step catalyst layers, in which the unsaturated aldehydes are oxidized by a second-step catalyst to produce unsaturated acids, wherein a first catalyst layer of the second-step catalyst layers, disposed right adjacent to the first-step catalyst layer, has an activity corresponding to 5˜30% of the activity of the catalyst layer having a highest activity among the second-step catalyst layers. A method of producing unsaturated acids from olefins by using the reactor is also disclosed.

Abstract: The present invention provides: a palladium-containing supported catalyst which is used for producing an ?,?-unsaturated carboxylic acid from an olefin or an ?,?-unsaturated aldehyde in high selectivity; a method for manufacturing the catalyst; and a method for producing an ?,?-unsaturated carboxylic acid in high selectivity. In particular, the present invention resides in a method for manufacturing a palladium-containing supported catalyst for producing an ?,?-unsaturated carboxylic acid from an olefin or an ?,?-unsaturated aldehyde, comprising the step of reducing palladium oxide contained in a catalyst precursor wherein at least the palladium oxide is supported on a carrier. By using such a palladium-containing supported catalyst, an ?,?-unsaturated carboxylic acid is produced through liquid-phase oxidation of an olefin or an ?,?-unsaturated aldehyde with molecular oxygen.

Abstract: The present invention relates to an integrated process for producing unsaturated carboxylic acids from the corresponding C2-C4 alkane. The process begins with performance of thermally integrated dehydrogenation reactions which convert a C2-C4 alkane to its corresponding C2-C4 alkene, and which involve exothermically converting a portion of an alkane to its corresponding alkene by oxidative dehydrogenation in an exothermic reaction zone, in the presence of oxygen and a suitable catalyst, and then feeding the products of the exothermic reaction zone to an endothermic reaction zone wherein at least a portion of the remaining unconverted alkane is endothermically dehydrogenated to form an additional quantity of the same corresponding alkene, in the presence of carbon dioxide and an other suitable catalyst.

Abstract: A process for starting-up a heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid or of methacrolein to methacrylic acid over a fixed catalyst bed disposed in a tube bundle reactor cooled by a heat exchange medium, wherein the temperature of the heat exchange medium is ?290° C. and the temperature of that reactor plate surface which faces the reaction gas entry mixture and the temperature of the reaction gas entry mixture itself are ?285° C.

Abstract: [Problem] There is provided, in a process for producing acrylic acid having a catalytic gas-phase oxidation reaction step, a condensation step, a collection step, a distillation step, a crystallization step, an acrylic acid recovering step or the like, a production method for acrylic acid, in which contamination of acrylic acid with protoanemonin without providing any additional purification treatment to the resultant purified acrylic acid can be reduced.

Abstract: The invention relates to a method for producing acrylic acid in one step by an oxydehydration reaction of glycerol in the presence of molecular oxygen. The reaction preferably carried out in gaseous phase in the presence of a suitable catalyst.

Abstract: A process for preparing at least one partial oxidation and/or ammoxidation product of a hydrocarbon by partially dehydrogenating at least one saturated hydrocarbon H under heterogeneous catalysis and using the resulting product gas mixture A, which comprises the partially dehydrogenated hydrocarbon H, as such or in modified form for heterogeneously catalyzed partial oxidation and/or ammoxidation of the partially dehydrogenated hydrocarbon present in the product gas mixture A, said process including at least one mechanical separating operation inserted between the product gas mixture A and the heterogeneously catalyzed partial oxidation and/or ammoxidation.

Abstract: A catalyst for the oxidation of an alkane, alkene or mixtures thereof. The catalyst includes a mixed-metal oxide having the formula MoaVbNbcTedSbeOf wherein, when a=1, b=0.01 to 1.0, c=0.01 to 1.0, d=0.01 to 1.0, e=0.01 to 1.0, and f is dependent upon the oxidation state of the other elements, the catalyst further characterized by having at least two crystal phases, the first crystal phase being an orthorhombic M1 phase and the second crystal phase being a pseudo-hexagonal M2 phase, the orthorhombic M1 phase present in an amount between greater than 60 weight percent to less than 90 weight percent. The catalysts disclosed herein exhibit a chemisorption of NH3 of less than about 0.2 mmole per gram of metal oxide.

Abstract: Materials for making apparatus and a method of inhibiting polymerization during manufacture, purification, handling and storage of subject ethylenically unsaturated monomers are disclosed. In particular, copper or metals containing copper, in the presence of oxygen, have inhibit undesired polymerization resulting in polymer fouling in apparatus used during the manufacture, purification, handling and storage of the monomers, such as acrylic acid, methacrylic acid, acrylic acid esters and methacrylic acid esters. The copper or copper alloys as described herein, in the presence of an oxygen-containing gas, exhibit self-inhibiting surface characteristics when used to make at least a portion of the apparatus to inhibit polymerization of the monomers in contact with the portion of the apparatus including such copper-containing metal.

Abstract: A process for preparing acrolein or acrylic acid or a mixture thereof as the target product from propane, in which propane is partially dehydrogenated under heterogeneous catalysis in a reaction zone A, molecular hydrogen formed is at least partly combusted to water, any water present in the product gas A formed in reaction zone A is removed therefrom and product gas A is otherwise used to charge a reaction zone B in which propylene formed in reaction zone A is partially oxidized in the presence of remaining propane to give the target product. The target product is removed from the product gas B formed in reaction zone B and propane present in the remaining residual gas is absorbed therefrom into a solvent and, after release from the absorbate, recycled into reaction zone A.

Abstract: Conventional gas-phase catalytic oxidation reaction apparatus comprising two reactors for production of acrylic acid is subject to problems of high equipment costs for the reactors and piping, necessity for wide installation area and easy accumulation of carbides generated by autoxidation of acrolein. On the other hand, conventional reaction apparatus comprising a single reactor has the drawbacks that the composition of gas in the first stage reaction and in the second stage reaction cannot be optimized independently of each other, and that the allowable concentration of starting propylene is limited because of the risk of explosion.