Procedimiento para producir un compuesto de difenilsulfona

Procedimiento para la purificación de un compuesto representado por la fórmula (I): en la que R1 y R2 son, cada uno independientemente, halógeno, alquilo con 1 a 8 carbonos o alquenilo con 2 a 8carbonos; m y n son, cada uno independientemente, 0 o un número entero de 1 a 4; y R3 es alquilo con 1 a 8carbonos, alquenilo con 2 a 8 carbonos, cicloalquilo con 3 a 8 carbonos, bencilo, 4-clorobencilo o 2-feniletilo, quecomprende: ajustar un pH de una solución acuosa que contiene el compuesto de fórmula (I) a un valor prefijado (P1) en elintervalo de 8,4 a 8,7, extraer a continuación dicha solución acuosa con un solvente orgánico no miscible en agua, yseparar dicha solución acuosa extraída a una capa orgánica y una capa acuosa, en el que el compuesto defórmula (I) se encuentra en la capa orgánica separada y añadir agua a la capa orgánica separada, y ajustar el pH de la capa acuosa a un valor prefijado (P2) en elintervalo de 8,3 a 8,6, en el que el compuesto de fórmula (I) se encuentra en la capa orgánica separada. The present invention is to provide methods for preparing a compound of Formula (I) (wherein, R 1 and R 2 are each independently halogen, alkyl having 1 to 8 carbons or alkenyl having 2 to 8 carbons; m and n are each independently 0 or an integer of 1 to 4; and R 3 is alkyl having 1 to 8 carbons, alkenyl having 2 to 8 carbons, cycloalkyl having 3 to 8 carbons or optionally substituted aralkyl) reacting a compound of Formula (II) (wherein R 1 and R 2 , m and n are as defined above) with a compound of Formula (III) €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 3 -X€ƒ€ƒ€ƒ€ƒ€ƒ(III) (wherein R 3 is as defined above and X is halogen) in a solvent in the presence of a base and the compound of Formula (III) is (1) removed from the reaction mixture, (2) present in the reaction in 5 % by weight or less in the purification process or (3) removed by distillation. Additionally, the invention provides methods for preparing a compound of Formula (I) such that (4) the reaction process is carried out in a solvent containing 0.05 ppm or less of iron components, (5) the purification process is carried out in water containing 0.05 ppm or less of iron components, (6) the reaction process is carried out in a tank with a corrosion-resistant layer over the inner wall, (7) the purification process is carried out in a tank with a corrosion-resistant layer over the inner wall, (8) a chelating agent is added to the purification process or (9) the product is dried with mechanical stirring.