Abstract: A method for producing (meth)acrolein and/or (meth)acrylic acid by subjecting isobutylene and the like or propylene to a vapor-phase catalytic oxidation with molecular oxygen in the presence of a solid oxidation catalyst in a tubular type of fixed bed reactor, wherein a temperature of a hot-spot zone is sufficiently controlled and (meth)acrolein and (meth)acrylic acid are produced with a high yield. A method for producing (meth)acrolein and/or (meth)acrylic acid by passing a raw material gas comprising isobutylene and the like or propylene and oxygen through a catalyst layer in a tubular type of fixed bed reactor which is filled with a solid oxidation catalyst, which includes passing a gas containing isobutylene and the like or propylene in a concentration lower than that of the raw material gas, and oxygen through the catalyst layer for a period of one hour or more prior to passing the raw material gas through the catalyst layer.

Abstract: This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160° C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step).

Abstract: In a method for synthesizing methacrylic acid by using a fixed bed tube type reactor provided with a catalyst bed into which a solid oxidation catalyst is filled and with a heat medium bath and by flowing a raw material gas containing methacrolein and oxygen through the catalyst bed, the catalyst bed does not have any sections in which a temperature difference between the heat medium bath and the catalyst bed (?T) exceeds 35° C., and two or more high temperature zones in which each ?T is 15 to 35° C. are provided. According to this method, mathacrylic acid can be manufactured in higher yields.

Abstract: In a method of producing methacrylic acid by passing a material gas containing methacrolein, oxygen and water vapor through a reactor packed with a catalyst containing as the main component a compound oxide containing molybdenum and phosphorus, a concentration of methacrolein in the material gas is controlled in a range of 4 to 6.5 vol %, a molar ratio of the water vapor to the methacrolein in the material gas is controlled in a range of 1 to 2, and a space velocity of the material gas to the catalyst-packed layer is controlled in a range of 500 to 750 h?1, whereby deterioration of the catalyst is effectively inhibited.

Abstract: This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160° C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step). A methyl methacrylate polymer having adequately good optical properties and a plastic optical fiber having improved transmission performance can be prepared according to this invention.

Abstract: A method for producing (meth)acrolein and/or (meth)acrylic acid by subjecting isobutylene and the like or propylene to a vapor-phase catalytic oxidation with molecular oxygen in the presence of a solid oxidation catalyst in a tubular type of fixed bed reactor, wherein a temperature of a hot-spot zone is sufficiently controlled and (meth)acrolein and (meth)acrylic acid are produced with a high yield.

Abstract: This invention provides a process for manufacturing a methyl methacrylate polymer comprising the steps of feeding a monomer containing at least 80 wt % of methyl methacrylate and a radical polymerization initiator represented formula (III) to a reactor; polymerizing the material at a polymerization temperature of 110 to 160° C. under the conditions satisfying particular equations between an initiator concentration and a polymerization temperature; feeding a reaction mixture taken out from the reactor to a devolatilization step (feeding step); and separating and removing volatiles from the reaction mixture (devolatilization step). A methyl methacrylate polymer having adequately good optical properties and a plastic optical fiber having improved transmission performance can be prepared according to this invention.

Abstract: In a method of producing methacrylic acid by passing a material gas containing methacrolein, oxygen and water vapor through a reactor packed with a catalyst containing as the main component a compound oxide containing molybdenum and phosphorus, a concentration of methacrolein in the material gas is controlled in a range of 4 to 6.5 vol %, a molar ratio of the water vapor to the methacrolein in the material gas is controlled in a range of 1 to 2, and a space velocity of the material gas to the catalyst-packed layer is controlled in a range of 500 to 750 h−1, whereby deterioration of the catalyst is effectively inhibited.

Abstract: There is provided a superior decreasing method of an N-oxyl compound contained in an easily polymerizable material, according to which the N-oxyl compound contained in an easily polymerizable material can be sufficiently decreased and loss of the easily polymerizable material is little. The easily polymerizable material containing an N-oxyl compound and an acid are contacted with each other. In addition, not only the N-oxyl compound but also an organic titanium group compound contained in the easily polymerizable material can be sufficiently decreased.

Abstract: There is provided a superior decreasing method of an N-oxyl compound contained in an easily polymerizable material, according to which the N-oxyl compound contained in an easily polymerizable material can be sufficiently decreased and loss of the easily polymerizable material is little. The easily polymerizable material containing an N-oxyl compound and an acid are contacted with each other. In addition, not only the N-oxyl compound but also an organic titanium group compound contained in the easily polymerizable material can be sufficiently decreased.

Abstract: In a method for synthesizing methacrylic acid by using a fixed bed tube type reactor provided with a catalyst bed into which a solid oxidation catalyst is filled and with a heat medium bath and by flowing a raw material gas containing methacrolein and oxygen through the catalyst bed, the catalyst bed does not have any sections in which a temperature difference between the heat medium bath and the catalyst bed (&Dgr;T) exceeds 35° C., and two or more high temperature zones in which each &Dgr;T is 15 to 35° C. are provided. According to this method, mathacrylic acid can be manufactured in higher yields.

Abstract: A carboxylic acid ester is prepared by a process comprising: reacting an aldehyde and an alcohol in a liquid phase in the presence of molecular oxygen as indicated by the following reaction: RCHO+R′OH+O2→RCOOR′+H2O in the presence of a catalyst comprising at least palladium and an element X, wherein X is bismuth, lead or a combination thereof, supported on a carrier, wherein the catalyst has an acid strength, pKa, of more than 4.8 and shows an ammonia chemical adsorption amount at 0° C. of 0-150 &mgr;mol/g-catalyst.

Abstract: A process for producing methacrolein and methacrylic acid by catalytically oxidizing isobutylene or tertiary butanol in the presence of a catalyst comprising a compound oxide containing molybdenum, bismuth and iron as the essential components, wherein a catalytic oxidation reaction is started at a temperature of (T−3)° C. or lower wherein T° C. is defined as the boundary temperature of activation energy of a reaction for obtaining methacrolein and methacrylic acid from isobutylene using said catalyst, the reaction is continued while the reaction temperature is increased as the activity of the catalyst decreases, and an activation treatment is conducted for the catalyst at least once before the reaction temperature exceeds the boundary temperature of activation energy.

Abstract: A catalyst for the production of carboxylic acid esters for use in reacting an aldehyde with an alcohol in a liquid phase in the presence of molecular oxygen, comprising calcium carbonate and palladium, bismuth and at least one element selected from the group consisting of barium, iron, zinc and germanium, these elements being supported on said calcium carbonate.

Abstract: A method for packing of catalyst, which comprises mixing, into a shaped catalyst containing at least molybdenum and iron, used in the gas-phase catalytic oxidation of propylene, isobutylene, tert-butyl alcohol or methyl tert-butyl ether with molecular oxygen to synthesize an unsaturated aldehyde and an unsaturated carboxylic acid both corresponding to the raw material used, metal-made Raschig rings as auxiliary packing material having a bulk volume of 0.3-3.5 times that of the shaped catalyst and a packing density of 0.5-1.5 kg/l, and packing the resulting mixture into a fixed bed type reactor; and a process for producing an unsaturated aldehyde and an unsaturated carboxylic acid, which comprises subjecting propylene, isobutylene, tert-butyl alcohol or methyl tert-butyl ether to gas-phase catalytic oxidation using molecular oxygen, in a fixed bed type reactor wherein a catalyst is packed by the above method.

Abstract: There is provided a process for efficient production of a solid catalyst usable for synthesis of methacrylic acid from methacrolein which comprises adding a lower alcohol or acetone to a dried product obtained from a mixed solution or aqueous slurry containing at least Mo, P and V as catalyst components and shaping the mixture by extrusion molding.

Abstract: A carrier-supported catalyst for the synthesis of unsaturated aldehydes and unsaturated carboxylic acids, comprising a catalyst active substance comprising at least molybdenum and bismuth as its components, glass fiber having an average diameter in a range of more than 5 .mu.m and not more than 200 .mu.m and an average length in a range of from 50 .mu.m to 1 mm, which is used as a carrier assistant in an amount of 0.5-50% by weight based on the catalyst active substance, and a carrier. The carrier-supported catalyst of this invention suffers no release or fall-off of the catalyst active substance from the carrier even if the catalyst supporting rate is increased. It also has high mechanical strength and is helpful for providing the objective product in a high yield.

Abstract: A method of preparing a catalyst used for producing methacrylic acids through gas phase catalytic oxidation of methacrolein with molecular oxygen. The catalyst is represented by the formula:P.sub.a Mo.sub.b V.sub.c Ge.sub.d X.sub.e Y.sub.f Z.sub.g O.sub.hwherein P, Mo, V, Ge and O represent phosphorous, molybdenum, vanadium, germanium and oxygen, respectively; X represents at least one element selected from the group consisting of arsenic, antimony, bismuth, zirconium, tellurium, silver and boron; Y represents at lest one element selected from the group consisting of iron, copper, zinc, chromium, magnesium, tantalum, manganese, barium, gallium, cerium and lanthanum; Z represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a, b, c, d, e, f, g and h represent the atomic ratios of the respective elements, and when b=12, then a=0.5-3, c=0.01-3, d=0.01-3, e=0-3, f=0-3, g=0.

Abstract: Disclosed is a process for producing a multicomponent catalyst containing molybdenum and bismuth and used for synthesis of unsaturated aldehydes and unsaturated carboxylic acids, characterized in that dried starting materials for the catalyst are calcinated in an atmosphere containing 1 vol % or more of a nitrogen oxide and 0.5 vol % or more of oxygen.

Abstract: A process for preparing a catalyst used for production of methacrolein and methacrylic acid by vapor phase oxidation of isobutylene or tertiary butanol includes adding an organic high-molecular weight compound having an average particle size of 0.01 .mu.m to 10 .mu.m, especially polymethyl methacrylate and/or polystyrene, to a MoBiFeCoNi-based catalyst, then molding the mixture and heat treating the molded product.