A reactor for exothermic or endothermic catalytic chemical reactions which comprises: a. a substantially cylindrical container (A) wherein feeding and discharging means of a thermoregulation fluid for the involved chemical reaction are present; b. a top closing element (B1) and a bottom closing element (B2) placed at the top and bottom ends of the container, respectively; c. feeding means of the reagent phase positioned in the top closing element and/or in the bottom closing element ; d. discharging means of the reacted phase positioned in the top closing element and/or in the bottom closing element ; e. one or more tubular elements , arranged vertically inside the container (A) between the top closing element (B1) and the bottom closing element (B2), each tubular element containing in its interior at least one body having the structure of a rigid open-cell foam made of a material having an intrinsic thermal conductivity higher than 10 W/m/K, said body being filled with a catalyst, also supported, in the form of particles, wherein: - an average pore size of the open-cell foam ranges from 0.25 to 10 mm, wherein said average pore size is measured considering polygonal structures of pores as being circles comprising same surface area, said average pore size is indicated as an average diameter of said circles and is calculated by evaluating a representative number of said pores for each sample, - a filling ratio, between the volume of the particles and the volume of the void space available in the open-cell foam, ranges from 0.4 and 0.8, - a filling degree of the open-cell foam ranges from 10 to 40%, wherein said filling degree is defined as the ratio between the density of the foam and the density of a full solid made of the same material, and - a ratio between the average pore size in the open-cell foam and an average size of the catalyst particles ranges from 1.1 to 30, wherein said average size of the catalyst particles being assessed using a laser granulometer. a. a substantially cylindrical container (A) wherein feeding and discharging means of a thermoregulation fluid for the involved chemical reaction are present; b. a top closing element (B1) and a bottom closing element (B2) placed at the top and bottom ends of the container, respectively; c. feeding means of the reagent phase positioned in the top closing element and/or in the bottom closing element ; d. discharging means of the reacted phase positioned in the top closing element and/or in the bottom closing element ; e. one or more tubular elements , arranged vertically inside the container (A) between the top closing element (B1) and the bottom closing element (B2), each tubular element containing in its interior at least one body having the structure of a rigid open-cell foam made of a material having an intrinsic thermal conductivity higher than 10 W/m/K, - an average pore size of the open-cell foam ranges from 0.25 to 10 mm, wherein said average pore size is measured considering polygonal structures of pores as being circles comprising same surface area, said average pore size is indicated as an average diameter of said circles and is calculated by evaluating a representative number of said pores for each sample, - a filling ratio, between the volume of the particles and the volume of the void space available in the open-cell foam, ranges from 0.4 and 0.8, - a filling degree of the open-cell foam ranges from 10 to 40%, wherein said filling degree is defined as the ratio between the density of the foam and the density of a full solid made of the same material, and - a ratio between the average pore size in the open-cell foam and an average size of the catalyst particles ranges from 1.1 to 30, wherein said average size of the catalyst particles being assessed using a laser granulometer. <EOS>