A novel process can be used for producing methacrylates such as methacrylic acid and/or alkyl methacrylates, in particular MMA. The process leads to an increased yield and increased efficiency compared to other C4-based production processes, in particular processes starting from isobutylene or tert-butanol as raw material. The process can be operated for longer periods without disruption and with the same or even increased activities and selectivities. The process can also be executed in a manner that is as simple, cost-effective, and environmentally friendly as possible.

A process for the continuous production of either acrolein or acrylic acid as the target product from propene comprising a catalyzed gas phase partial oxidation of propene to yield a product gas containing the target product, transferring the target product in a separating zone from the product gas into the liquid phase and conducting out of the separating zone a stream of residual gas the major portion of which is returned into the partial oxidation and the remaining portion of said stream is purged from the process as off-gas from which synthesis gas can be produced or which can be added to synthesis gas produced otherwise.

A process for the continuous production of either acrolein or acrylic acid as the target product from propene comprising a catalyzed gas phase partial oxidation of propene to yield a product gas containing the target product, transferring the target product in a separating zone from the product gas into the liquid phase and conducting out of the separating zone a stream of residual gas the major portion of which is returned into the partial oxidation and the remaining portion of said stream is purged from the process as off-gas from which synthesis gas can be produced or which can be added to synthesis gas produced otherwise.

The present invention relates to a process for preparing a poly(meth)acrylic acid, characterized in that a (meth)acrylic acid-containing process stream from (meth)acrolein synthesis is subjected to free-radical polymerization. The invention also relates to the esterification of the polymer obtained to give a homopolymer or copolymer ester, and to the use thereof as additive, flow improver and water reducer.

The present invention relates to a process for preparing a poly(meth)acrylic acid, characterized in that a (meth)acrylic acid-containing process stream from (meth)acrolein synthesis is subjected to free-radical polymerization. The invention also relates to the esterification of the polymer obtained to give a homopolymer or copolymer ester, and to the use thereof as additive, flow improver and water reducer.

A method for producing (meth)acrolein by vapor-phase catalytic oxidation of propylene or isobutylene in a multitubular reactor including a plurality of reaction tubes, the reaction tubes each including a reaction zone filled with a catalyst including molybdenum oxide and a cooling zone filled with an inert substance, wherein a temperature of a heat medium that flows outside the cooling zone is lower than a temperature of a heat medium that flows outside the reaction zone, and wherein the inert substance includes an inert substance having a major-axis length that is equal to or more than 1.7 times a major-axis length of the catalyst. A method for producing (meth)acrylic acid in which (meth)acrolein thus produced is converted to (meth)acrylic acid by vapor-phase catalytic oxidation.

A method for producing (meth)acrolein by vapor-phase catalytic oxidation of propylene or isobutylene in a multitubular reactor including a plurality of reaction tubes, the reaction tubes each including a reaction zone filled with a catalyst including molybdenum oxide and a cooling zone filled with an inert substance, wherein a temperature of a heat medium that flows outside the cooling zone is lower than a temperature of a heat medium that flows outside the reaction zone, and wherein the inert substance includes an inert substance having a major-axis length that is equal to or more than 1.7 times a major-axis length of the catalyst. A method for producing (meth)acrylic acid in which (meth)acrolein thus produced is converted to (meth)acrylic acid by vapor-phase catalytic oxidation.

A catalyst for producing unsaturated aldehyde and unsaturated carboxylic acid, wherein the cumulative pore volume (A) of pores having a pore diameter of 1 μm or more and 100 μm or less, in the catalyst, is 0.12 ml/g or more and 0.19 ml/g or less, and the ratio (A/B) of the cumulative pore volume (A) to the cumulative pore volume (B) of pores having a pore diameter of 1 μm or more and 100 μm or less, in a pulverized product not passing through a Tyler 6 mesh, in a pulverized product obtained by pulverization of the catalyst under a particular condition is 0.30 or more and 0.87 or less.

A catalyst for producing unsaturated aldehyde and unsaturated carboxylic acid, wherein the cumulative pore volume (A) of pores having a pore diameter of 1 μm or more and 100 μm or less, in the catalyst, is 0.12 ml/g or more and 0.19 ml/g or less, and the ratio (A/B) of the cumulative pore volume (A) to the cumulative pore volume (B) of pores having a pore diameter of 1 μm or more and 100 μm or less, in a pulverized product not passing through a Tyler 6 mesh, in a pulverized product obtained by pulverization of the catalyst under a particular condition is 0.30 or more and 0.87 or less.

Provided is a process for preparing acrolein by catalytic gas phase oxidation comprising (a) providing a reaction gas comprising (i) 5 to 10 mol % propylene, (ii) 0.02 to 0.75 mol % propane, and (iii) 0.25 to 1.9 mol % of a fuel mixture comprising at least one of methane and ethane, wherein the molar ratio of the total amount of propane, methane, and ethane to the total amount of propylene is from 0.01:1 to 0.25:1, and (b) contacting the reaction gas with a mixed metal oxide catalyst comprising one or more of molybdenum, bismuth, cobalt, and iron.