Abstract: Multimetal oxide materials containing molybdenum, vanadium, copper and antimony and one or more specific other metals and having a multicomponent structure are used for the gas-phase catalytic oxidative preparation of acrylic acid from acrolein.

Abstract: An object of this invention is to provide a method for producing acrylic acid that enables to suppress adverse influence of byproducts during distillation and to accomplish long-term continuous operation of the acrylic acid production apparatus. This invention is directed to a method for producing (meth)acrylic acid comprising the step of isolating (meth)acrylic acid from a liquid containing (meth)acrylic acid by distillation wherein the liquid contains glyoxal (including its hydrate) in a concentration of 0.1 mass % or less.

Abstract: A catalyst useful for catalytic vapor-phase oxidation of isobutylene, t-butanol or propylene to produce respectively corresponding unsaturated aldehyde and unsaturated carboxylic acid is provided. The catalyst consists of ring-formed shaped bodies composed of (i) a catalyst composition containing at least molybdenum and bismuth as the active ingredients and (ii) inorganic fibers. The catalyst excels in mechanical strength, can give the object products at high yield and shows little activity degradation with time.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid, the starting reaction gas mixture is oxidized over a fixed catalyst bed 1 which consists of at least two fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the transition from temperature zone A to temperature zone B does not coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: A process for heterogeneously catalyzed partial direct oxidation of propane and/or isobutane, in which target product is removed in a workup stage from the product gas mixture obtained in the reaction stage, the remaining residual product gas mixture is divided into two portions of the same composition, one portion is recycled into the reaction stage and the other portion is discharged, and both the reaction stage and the workup stage are operated at elevated pressure.

Abstract: In a process for partially oxidizing acrolein to acrylic acid in the gas phase under heterogeneous catalysis, the starting reaction gas mixture is oxidized at an acrolein loading of ≦145 and ≧70 l (STP) of acrolein/l of fixed catalyst bed·h over a fixed catalyst bed which is accommodated in two successive reaction zones A, B, the highest temperature of the reaction gas mixture within reaction zone A being above the highest temperature of the reaction gas mixture within reaction zone B.

Abstract: Multimetal oxide materials containing molybdenum, vanadium, antimony, one or more of the elements W, Nb, Ta, Cr and Ce and nickel and, if required, one or more of the elements Cu, Zn, Co, Fe, Cd, Mn, Mg, Ca, Sr and Ba and having a 2-component structure are used for the gas-phase catalytic oxidative preparation of acrylic acid.

Abstract: In a process for preparing a multiplephase multimetal oxide composition comprising Mo, V, Cu and, if desired, further elements, at least one phase is preformed separately and dispersed in a plastically deformable precursor composition of a further phase. The mixture is dried and calcined. The multimetal oxide composition is suitable as active composition of catalysts for the catalytically oxidation of organic compounds in the gas phase, in particular for the oxidation of acrolein to acrylic acid.

Abstract: A catalyst suited for catalytic vapor-phase oxidation of isobutylene, t-butanol or propylene to produce respectively corresponding unsaturated aldehyde and unsaturated carboxylic acid is provided. Said catalyst consists of ring-formed shaped bodies composed of (i) a catalyst composition containing at least molybdenum and bismuth as the active ingredients and (ii) inorganic fibers. The catalyst excels in mechanical strength, can give the object products at high yield and shows little activity degradation with time.

Abstract: A process is provided which can effectively inhibit occurrence of hot spots in reaction zones or heat accumulation at the hot spots, in the occasion of producing acrolein and acrylic acid through vapor phase oxidation of propylene in the presence of a catalyst using a fixed bed shell-and-tube reactor, said catalyst having a composition represented by a general formula (1): MoaWbBicFedAeBfCgDhEiOx (wherein A is at least an element selected from Co and Ni; B is at least an element selected from P, Te, As, B, Sb, Sn, Ce, Nb, Pb, Cr, Mn and Zn; C is alkali metal element; D is alkaline earth metal element; E is at least an element selected from Si, Al, Ti and Zr; and O is oxygen; a, b, c, d, e, f, g, h, i and x denote the atomic numbers of Mo, W, Bi, Fe, A, B, C, D, E and O, respectively, and where a is 12, b is 0-5, c is 0.1-10, d is 0.1-10, e is 1-20, fis 0-5, g is 0.001-3, h is 0-3, i is 0-30, and x is a numerical value which is determined depending on the extent of oxidation of each of the elements).

Abstract: Organic compounds are prepared by heterogeneously catalyzed partial gas-phase oxidation of precursor compounds by a process in which a portion of the reaction gas starting mixture is brought from a low initial pressure to a higher final pressure by means of a radial compressor.

Abstract: A process to produce ethyne comprising passing acetaldehyde in the gas phase through a reaction zone containing a dehydrating metal oxide catalyst such as aluminum oxide or magnesium oxide at a temperature of approximately 375 C. to produce ethyne and water and a cooling zone following the reaction zone.

Abstract: Compounds of formula (I), wherein R1 and R2 are, independently of one another, H,C1-C6alkyl, C1-C6halogenalkyl, C1-C6alkoxyl, C1-C6alkoxy-C1-C6alkyl, or C1-C6alkoxy-C1-C6alkyloxy, and R3 is C1-C6alkyl, are obtainable in high yiedls by stereoselective addition of R3-substituted propionic acid esters to R1- and R2-substituted benzaldehydes of formula R—CHO to form corresponding 3-R-3-hydroxy-2-R3-propionic acid esters, conversion of the OH group to a leaving group, subsequent regioselective elimination to form 3-R-2-R3-propenic acid esters, and reduction to corresponding 3-R-2-R3-allyl alcohols and their enantioselective hydrogenation, wherein R is (a).

Abstract: Reactor membranes for used in oxidation reactions of hydrocarbons involving oxygen comprising a selective oxidation catalyst on a mixed conducting, oxide ion selective ceramic membrane of the composition (Sr1-xCax)1-yAyMn1-zBzO3-&dgr;, where A is Ba, Pb, Na, K, Y, an element of the lanthanide group or a combination thereof, B is Mg, Al, Ga, In, Sn, an element of the 3d or 4d period or a combination thereof, x is from 0.2 to 0.8, y is from 0 to 0.4, z is from 0 to 0.6, and &dgr; is a number, dependent on x, y and z, that renders the composition charge neutral.

Abstract: A continuously operated heterogeneously catalyzed gas-phase partial oxidation of at least one organic compound in an oxidation reactor is operated safely by a process in which an explosion diagram for the feed gas mixture is deposited as the basis of a cut-out mechanism in a computer.

Abstract: A process for the heterogeneously catalyzed gas-phase partial oxidation of an organic compound over a fixed catalyst bed present in a fixed-bed reactor having a plurality of catalyst tubes, in which the reduction of the quality of the catalyst load with increasing duration of operation is restored by a partial catalyst change, is described.

Abstract: A method for the absorption of (meth)acrylic acid and/or (meth)acrolein and an apparatus thereof which, in an absorption column adapted to cause an (meth)acrylic acid and/or (meth)acrolein-containing gas obtained in consequence of catalytic gas phase oxidation to come into countercurrent contact with a solvent, contemplate using a packing of relatively high efficiency in absorption disposed on the upstream side of the flow of a liquid containing the solvent and a packing and/or trays of relatively low performance of forming polymerization disposed on the downstream side thereof, in the column.

Abstract: The present invention produces (meth)acrylic acid in a high yield in a process for producing (meth)acrylic acid by subjecting at least one member selected from the group consisting of (meth)acrolein, propane, and isobutane to catalytic gas phase oxidation with molecular oxygen or a molecular-oxygen-containing gas. In addition, the present invention makes it possible to produce (meth)acrylic acid in a high yield and stably for a long time. The present invention provides a process for producing (meth)acrylic acid by catalytic gas phase oxidation reaction, which is characterized by allowing a reaction gas to contain a reducible compound.

Abstract: The invention provides a process which, in producing acrylic acid through vapor-phase catalytic oxidation of acrolein-containing gas using a shell-and-tube type fixed bed reactor, can effectively inhibit occurrence of hot spots and produce acrylic acid at high yields. Said process is characterized by dividing each of the reaction tubes into at least three reaction zones in its axial direction, filling the first reaction zone closest to the gas inlet with a catalyst having a higher activity than that of the catalyst filling the adjacent, second reaction zone and filling the subsequent reaction zones with catalysts of different activity levels such that the catalytic activity successively rises from the second reaction zone toward the gas outlet side.

Abstract: A method for mixing a plurality of gases including forming a helical flow within a mixing vessel thereby allowing simplification of construction, avoiding pressure drop to the fullest possible extent, and expediting the mixture lest the volume of a gas within the explosion limits should increase, and an apparatus to be used for the method.

Abstract: A process for the fractional condensation of a gas mixture which, in addition to acrylic acid or methacrylic acid, also contains at least one further condensable component and additionally a high proportion of one or more noncondensable components, wherein the gas mixture is passed through a column having separatory internals and the condensable components are condensed by cooling.

Abstract: This invention relates to an improved process for preparing acrylic acid from propylene using a tandem reactor and utilizing an increased amount of propylene reactant, thereby providing increased capacity and throughput. An improved process for purifying acrylic acid is also disclosed.

Abstract: A novel method for preparing a heteropolyacid catalyst containing a heteropolyacid composed of molybdophosphoric acid and/or molybdovanadophosphoric acid, or a salt of the heteropolyacid, is provided. The method comprises preparing an aqueous solution or aqueous dispersion which (1) contains the nitrogen-containing heterocyclic compound, nitrate anions and ammonium ions, (2) the ammonium ion content not exceeding 1.7 mols per mol of the nitrate anion content, and (3) the ammonium ion content not exceeding 10 mols per 12 mols of the molybdenum atom content by mixing raw materials containing the catalyst-constituting elements with the nitrogen-containing heterocyclic compound in the presence of water, drying and calcining the same. This heteropolyacid catalyst excels over conventional catalysts in performance, life and strength.

Abstract: This invention relates to a high load process for preparing (meth)acrylic acid from a reactive hydrocarbon using a high reactive hydrocarbon space velocity to provide increased capacity and throughput.

Abstract: In the reaction of catalytic gas phase oxidation by means of a shell-and-tube type reactor adapted to circulate a heating medium to the shell of the reactor through the medium of a circulation device connecting an annular conduit connected thereto, a method for the catalytic gas phase oxidation characterized by subjecting a part of the heating medium extracted from the shell of the reactor to heat exchange, introducing the heating medium resulting from the heat exchange into the proximity of a heating medium circulation inlet on the inlet side of the circulation device or the annular conduit on the outlet side of the reactor. The flow rate of the heating medium after the heat exchange is preferred to be in the range of 2-40 vol. % based on the flow rate of the heating medium within the shell of the reactor and the temperature difference of the heating medium at the inlet and the outlet to be in the range of 15-150° C.

Abstract: This invention is related to a shell-and-tube type reactor provided with reaction tubes packed with a catalyst and adapted to circulate a heat medium to the fluid outside the tubes and is characterized by a method introducing a gas into the catalyst beds so as to retain the relative humidity of the catalyst in the range of more than 40% while elevating the temperature of the reactor thereby starting up the reactor. This method prevents the catalyst from degradation of activity due to absorption of moisture, exalts the service life of the catalyst, and permits stable production of methacrylic acid.

Abstract: For use in a process for the production of (meth)acrylic acid comprising at least a step for the reaction of (meth)acrylic acid by catalytic gas phase oxidation and a step for the absorption thereof, a method for preventing an effluent gas pipe from blocking is disclosed, which method is characterized by causing part or the whole of the gas discharged from the step for absorption, while being circulated via the effluent gas pipe to the step for the reaction or being discarded, to be subjected to temperature elevation and application of pressure and/or mist separation. Particularly by setting the temperature of the waste gas from the absorption column at a level in the range of 30-70° C.

Abstract: A process for producing acrylic acid through vapor-phase catalytic oxidation of acrolein or acrolein-containing gas with molecular oxygen or a molecular oxygen-containing gas using a catalyst-filled fixed bed shell-and-tube reactor is provided, which is characterized in that plural catalysts of different activity levels which are prepared by changing the kind and/or amount of alkaline metal(s) therein are filled in the reaction tubes in such an arrangement that the activity levels rise from the gas-inlet side toward the gas-outlet side of said tubes. According to this process, not only yield and productivity of acrylic acid are improved but also excessive heat, accumulation in the catalyst layer can be inhibited and catalysts degradation under heat is prevented, resulting in prolongation of catalyst life.

Abstract: An object of this invention is to provide a method for producing acrylic acid that enables to suppress adverse influence of byproducts during distillation and to accomplish long-term continuous operation of the acrylic acid production apparatus. This invention is directed to a method for producing (meth)acrylic acid comprising the step of isolating (meth)acrylic acid from a liquid containing (meth)acrylic acid by distillation wherein the liquid contains glyoxal (including its hydrate) in a concentration of 0.1 mass % or less.

Abstract: A modified carrier carrying on at least a part of an inert carrier surface an oxide which is represented by the formula (1): XaYbZcOd (wherein X is at least an element selected from alkaline earth metals; Y is at least an element selected from Si, Al, Ti and Zr; Z is at least an element selected from Group IA elements and Group IIIb elements of the periodic table, B, Fe, Bi, Co, Ni and Mn; and O is oxygen; a, b, c and d denote the atomic ratios of X, Y, Z and O, respectively, where a=1, 0<b≦100, 0≦c≦10, and d is a numerical value determined by the extents of oxidation of the other elements) is provided. A catalyst formed with the use of this modified carrier carrying a complex oxide containing Mo and V is useful as a vapor phase catalytic oxidation catalyst, and is particularly suitable as a catalyst for preparing acrylic acid through vapor phase catalytic oxidation of acrolein.

Abstract: The invention provides a process which, in producing acrylic acid through vapor-phase catalytic oxidation of acrolein-containing gas using a shell-and-tube type fixed bed reactor, can effectively inhibit occurrence of hot spots and produce acrylic acid at high yields. Said process is characterized by dividing each of the reaction tubes into at least three reaction zones in its axial direction, filling the first reaction zone closest to the gas inlet with a catalyst having a higher activity than that of the catalyst filling the adjacent, second reaction zone and filling the subsequent reaction zones with catalysts of different activity levels such that the catalytic activity successively rises from the second reaction zone toward the gas outlet side.

Abstract: A process for the catalytic gas-phase oxidation of propene to acrylic acid, in which the reaction gas starting mixture is oxidized, with an increased propene loading, in a first reaction stage, over a first fixed-bed catalyst and then the acrolein-containing product gas mixture of the first reaction stage is oxidized, in a second reaction stage, with an increased acrolein loading, over a second fixed-bed catalyst, the catalyst moldings in both reaction stages having an annular geometry.

Abstract: This invention relates to a process for preparing (meth)acrylic acid, whereby turndown control is utilized to maintain optimal distillation column performance in the dehydration of aqueous (meth)acrylic acid to provide a (meth)acrylic acid solution.

Abstract: The present invention produces (meth)acrylic acid in a high yield in a process for producing (meth)acrylic acid by subjecting at least one member selected from the group consisting of (meth)acrolein, propane, and isobutane to catalytic gas phase oxidation with molecular oxygen or a molecular-oxygen-containing gas. In addition, the present invention makes it possible to produce (meth)acrylic acid in a high yield and stably for a long time. The present invention provides a process for producing (meth)acrylic acid by catalytic gas phase oxidation reaction, which is characterized by allowing a reaction gas to contain a reducible compound.

Abstract: Processes are disclosed for the oxidation of alkanes such as, for example, propane, to form unsaturated carboxylic aldehydes and acids such as, for example, acrolein and acrylic acid. The processes utilize oxygen and recycle alkanes, e.g. propane, to the aldehyde reactor. The presence of the alkane-to-aldehyde reaction can enhance the efficiency of the processes.

Abstract: A method of producing highly purified acrylic acid in a high yield is provided. A method of producing acrylic acid including the steps of an oxidation step, an absorption step, a distillation step, a crystallization step, and a dimer decomposition step.

Abstract: Improved catalyst for use in production of methacrylic acid by vapor phase oxidation reaction and/or vapor phase oxidative dehydrogenation reaction of at least one compound selected from methacrolein, isobutylaldehyde and isobutyric acid is provided. This improved catalyst is a composition composed of (A) complex oxide containing as essential components molybdenum and phosphorus, which is per se known as a catalyst for the above reaction(s), and (B) complex oxide containing as essential components cerium and zirconium. When this improved catalyst is used, the operation for producing methacrylic acid can be stably continued over prolonged period.

Abstract: Provided is a process for producing acrylic acid stably at a high yield over a long period of time by subjecting acrolein or acrolein-containing gas to catalytic vapor phase oxidation. The above process is characterized by controlling the reaction so that the following equations (1) and (2) are satisfied: 1° C.≦T0−T1≦15° C.  (1) T1<T2  (2) wherein T0 represents a temperature of acrolein or the acrolein-containing gas in an inlet of a catalyst layer; T1 represents a temperature in an inlet part of the catalyst layer; and T2 represents a temperature in an outlet part of the catalyst layer.

Abstract: A method for purifying acrylic acid, which comprises carrying out dehydration distillation of an aqueous solution of acrylic acid by means of a dehydration column, wherein a distillation column having a theoretical plate number of at least 3 plates is used as the dehydration column, and the operational temperature of a site corresponding to the second theoretical plate is adjusted to be from 50 to 78° C.

Abstract: The present invention provides a catalyst composition for the production of carboxylic acids by the oxidation of the corresponding unsaturated aldehydes, and methods for making and using the catalyst compositions.

Abstract: A catalyst for the production of acrylic acid by the vapor-phase catalytic oxidation of acrolein or acrolein-containing gas and a method for the production of acrylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a catalyst having Mo and V as essential components and used for the production of acrylic acid by vapor-phase catalytic oxidation of acrolein and (B) a solid acid having acid strength (Ho) of not more than −11.93. Since this catalyst excels in catalytic activity and service life, it allows acrylic acid to be produced stably at a high yield for a long time.

Abstract: In a process for the preparation of acrolein and/or acrylic acid from propane, the propane is subjected, in a first reaction stage, to an oxydehydrogenation with molecular oxygen under homogeneous and/or heterogeneous catalysis to give propene and the product gas mixture formed in the first reaction stage is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propene oxidation.

Abstract: A process for selectively oxidizing an organic molecule by reacting said organic molecule and oxygen in the presence of a selective oxidation catalyst supported on a mesh-like structure.

Abstract: The present invention provides a method for stabilizing waste oil which is taken of each chemical apparatus of the manufacturing line of (meth)acryl acid and/or ester thereof, and treating the waste oil such as draining it out of the production apparatus, for example, a distillation tower from its bottom, sending and transporting it by a pump through a pipeline, and storing it in a storage tank in a simple manner while keeping the waste oil in a stable state. The waste oil can be stabilized by coexisting with solvent. The solvent used in the present invention is typically at least one selected from the group consisting of water, alcohol, ether, carboxylic acid, ketone, aromatic hydrocarbons, and aliphatic hydrocarbons.

Abstract: In a process for the preparation of acrolein by gas-phase partial oxidation under heterogeneous catalysis, a reaction gas starting mixture which contains propene and molecular oxygen in a molar C3H6:O2 ratio of >1 is reacted in reaction zones connected in series, at elevated temperatures, over solid-state catalysts, further molecular oxygen being added to the reaction gas mixture in the course of the partial oxidation.

Abstract: In a method for producing acrylic acid by the steps of a reaction of catalytic gas phase oxidation, absorbing the acrylic acid with an absorbent, and dehydrating the acrylic acid-containing aqueous solution, the method is characterized that the step of dehydration comprises adding and an azeotropic solvent, distilling the resultant mixture, and adjusting the acrylic acid concentration at the top of the column in the range of 0.06-0.80 wt. %, thereby preventing the bottoms of the azeotropic dehydration column from substantially containing the azeotropic solvent and water. As results, the acrylic acid is kept from forming a polymer in any of the distillation columns involved in the production, and effective utilization of acrylic acid.

Abstract: In a process for the catalytic gas-phase oxidation of acrolein to acrylic acid, the reaction gas starting mixture is passed, with an acrolein loading of ≧150 l (s.t.p.)/l.h, over a fixed-bed catalyst which is housed in two spatially successive reaction zones A, B, the reaction zone B being kept at a higher temperature than the reaction zone A.

Abstract: As an improvement in the process for preparing unsaturated aldehydes and unsaturated carboxylic acids through vapor-phase catalytic oxidation of at least one starting compound selected from propylene, isobutylene, t-butanol and methyl-t-butyl ether with molecular oxygen or a molecular oxygen-containing gas, using a fixed bed shell-and-tube type reactor which is filled with shaped catalysts, a process capable of effectively inhibiting occurrence of hot spots or excessive heat generation at the hot spots and producing unsaturated aldehydes and unsaturated carboxylic acids at high yields is provided.

Abstract: In a process for the catalytic gas-phase oxidation of propene to acrolein, the reaction gas starting mixture is passed with a propene loading of ≧160 l(S.T.P.)/l·h over a fixed-bed catalyst which is housed in two spatially successive reaction zones A,B, the reaction zone B being kept at a higher temperature than the reaction zone A.

Abstract: This invention relates to an improved process for preparing acrylic acid from propylene using a single reactor utilizing an increased amount of propylene reactant thereby providing increased capacity and throughput.