Process for producing a catalyst comprising at least the element tantalum, and at least one silica-based mesoporous oxide matrix, the weight of tantalum representing between 0.1 and 30% of the weight of said mesoporous oxide matrix, comprising at least the following steps: a) at least one step of acid washing of a silica-based mesoporous oxide matrix comprising, before washing, at least 90% by weight of silica, said silica-based mesoporous oxide matrix, before washing, being a mesoporous amorphous silica with a non-organized porosity with no micropores, having a BET specific surface area of at least 250 m 2 /g, the weight percentages being expressed relative to the total weight of the mesoporous oxide matrix, said washing being carried out by means of bringing into contact with at least one inorganic acid, chosen from nitric acid, sulfuric acid and hydrochloric acid, diluted in an aqueous solution at a concentration within the range of from 0.05 M to 3 M, at a temperature of between 0°C and 120°C and a contact time of said acid solution with said mesoporous oxide matrix of between 10 min and 10 h, b) at least one step of heat treatment of said washed matrix resulting from step a), said heat treatment being drying carried out at a temperature of from 80 to 300°C for a period of less than 24 h, so as to obtain a catalyst support, c) at least one step of deposition of at least one metal precursor of at least the element tantalum on the surface of said support obtained at the end of step b), and d) at least one step of heat treatment of the solid resulting from step c), said heat treatment being drying followed by calcination, the drying being carried out under circulation of air at a temperature between 80 and 150°C for a period of between 1 and 24 hours, and the calcination being carried out under circulation of a gas stream comprising oxygen, at a temperature between 450 and 600°C, for a period of between 1 and 6 hours. a) at least one step of acid washing of a silica-based mesoporous oxide matrix comprising, before washing, at least 90% by weight of silica, said silica-based mesoporous oxide matrix, before washing, being a mesoporous amorphous silica with a non-organized porosity with no micropores, having a BET specific surface area of at least 250 m 2 /g, the weight percentages being expressed relative to the total weight of the mesoporous oxide matrix, said washing being carried out by means of bringing into contact with at least one inorganic acid, chosen from nitric acid, sulfuric acid and hydrochloric acid, diluted in an aqueous solution at a concentration within the range of from 0.05 M to 3 M, at a temperature of between 0°C and 120°C and a contact time of said acid solution with said mesoporous oxide matrix of between 10 min and 10 h, b) at least one step of heat treatment of said washed matrix resulting from step a), said heat treatment being drying carried out at a temperature of from 80 to 300°C for a period of less than 24 h, so as to obtain a catalyst support, c) at least one step of deposition of at least one metal precursor of at least the element tantalum on the surface of said support obtained at the end of step b), and d) at least one step of heat treatment of the solid resulting from step c), said heat treatment being drying followed by calcination, the drying being carried out under circulation of air at a temperature between 80 and 150°C for a period of between 1 and 24 hours, and the calcination being carried out under circulation of a gas stream comprising oxygen, at a temperature between 450 and 600°C, for a period of between 1 and 6 hours. <EOS>