A new process of gaseous-phase dealkylation of alkylphenols by heterogeneous catalysis (NiSO 4 Al 2 O 3 ) through a tubular reactor is described. The process is studied with an experimental design using the de-tert-butylation reaction of 4-tert-butyl-2,6-dimethylphenol as a model, and we show that the process does not noticeably depend on the variation of the experimental conditions. Under optimum conditions, the conversion is 98% and the selectivity 100%. The same process is applied to various alkylphenols to give high conversion and selectivity (generally higher than 95%).Nous decrivons un nouveau procede de desalkylation d'alkylphenols en phase gazeuse par catalyse heterogene (NiSO 4 Al 2 O 3 ) dans un reacteur tubulaire. L'etude de la reaction de de-tert-butylation du 4-tert-butyl-2,6-dimethylphenol (reaction modele) par les plans d'experiences montre que le procede ne depend pas notablement de la variation des conditions experimentales. Dans les conditions optimales, nous obtenons un taux de conversion de 98 % et une selectivite de 100 %. L'application de ce procede a divers alkylphenols conduit dans les conditions optimales a des taux de conversion et a des selectivites generalement superieurs a 95 %.