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 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 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.

Provided is a method for producing an unsaturated aldehyde including subjecting an alkene to partial oxidation using a fixed bed multi-tube reactor to produce the corresponding unsaturated aldehyde, in which n catalyst layers (n is 2 or more) in a gas flow direction in a reaction tube are provided, when a filling length of the catalyst layers from a first catalyst layer to an (n-1)th catalyst layer from a gas inlet side of the reaction tube is L, and a filling length of an nth catalyst layer from the gas inlet side of the reaction tube is Ln, a relationship between L and Ln satisfies the following equation (1):

[00001]$\begin{array}{cc}1<L\text{/}\mathrm{Ln}\le 3,& \left(1\right)\end{array}$ and a composition of a catalytically active component contained in the catalyst layers from the first catalyst layer to the (n-1)th layer from the gas inlet side of the reaction tube is different from a composition of a catalytically active component contained in the nth catalyst layer from the gas inlet side of the reaction tube.

Provided is a method for producing an unsaturated aldehyde including subjecting an alkene to partial oxidation using a fixed bed multi-tube reactor to produce the corresponding unsaturated aldehyde, in which n catalyst layers (n is 2 or more) in a gas flow direction in a reaction tube are provided, when a filling length of the catalyst layers from a first catalyst layer to an (n-1)th catalyst layer from a gas inlet side of the reaction tube is L, and a filling length of an nth catalyst layer from the gas inlet side of the reaction tube is Ln, a relationship between L and Ln satisfies the following equation (1):

[00001]$\begin{array}{cc}1<L\text{/}\mathrm{Ln}\le 3,& \left(1\right)\end{array}$ and a composition of a catalytically active component contained in the catalyst layers from the first catalyst layer to the (n-1)th layer from the gas inlet side of the reaction tube is different from a composition of a catalytically active component contained in the nth catalyst layer from the gas inlet side of the reaction tube.

Provided is a method for producing an unsaturated aldehyde including subjecting an alkene to partial oxidation using a fixed bed multi-tube reactor to produce the corresponding unsaturated aldehyde, in which n catalyst layers (n is 2 or more) in a gas flow direction in a reaction tube are provided, when a filling length of the catalyst layers from a first catalyst layer to an (n-1)th catalyst layer from a gas inlet side of the reaction tube is L, and a filling length of an nth catalyst layer from the gas inlet side of the reaction tube is Ln, a relationship between L and Ln satisfies the following equation (1):

[00001]$\begin{array}{cc}1<L\text{/}\mathrm{Ln}\le 3,& \left(1\right)\end{array}$ and a composition of a catalytically active component contained in the catalyst layers from the first catalyst layer to the (n-1)th layer from the gas inlet side of the reaction tube is different from a composition of a catalytically active component contained in the nth catalyst layer from the gas inlet side of the reaction tube.

A method of loading granules into reaction tubes of a vertical multitube reactor installed in a vertical direction by dropping the granules from above each of the reaction tubes in a state that a linear member is inserted and suspended in the reaction tube. The reaction tube has an effective length of 1000 mm or more. The linear member includes a small-diameter portion positioned on an upper side and a large-diameter portion continuously extending from the small-diameter portion. The small-diameter portion has an outer diameter (Ra) of 5.0 mm or less, and the large-diameter portion has an outer diameter (Rb) of 5.0 to 15.0 mm larger than the outer diameter (Ra). A length of the small-diameter portion from an upper end of the reaction tube is 10.0 mm or more. A distance between an upper surface of a granule loaded layer formed inside the reaction tube and a lower end of the linear member inserted in the reaction tube is 100 mm or more.

A method of loading granules into reaction tubes of a vertical multitube reactor installed in a vertical direction by dropping the granules from above each of the reaction tubes in a state that a linear member is inserted and suspended in the reaction tube. The reaction tube has an effective length of 1000 mm or more. The linear member includes a small-diameter portion positioned on an upper side and a large-diameter portion continuously extending from the small-diameter portion. The small-diameter portion has an outer diameter (Ra) of 5.0 mm or less, and the large-diameter portion has an outer diameter (Rb) of 5.0 to 15.0 mm larger than the outer diameter (Ra). A length of the small-diameter portion from an upper end of the reaction tube is 10.0 mm or more. A distance between an upper surface of a granule loaded layer formed inside the reaction tube and a lower end of the linear member inserted in the reaction tube is 100 mm or more.

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 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.