Abstract: The present disclosure relates to a dehydration catalyst, a method for preparing the same, and a method for preparing an alkene using the same. More particularly, the present invention relates to a dehydration catalyst that is mixed-phase alumina including 1 to 18% by weight of alpha-alumina, 65 to 95% by weight of theta-alumina, and 4 to 34% by weight of delta-alumina, a method for preparing the dehydration catalyst, and a method for preparing an alkene using the dehydration catalyst.

Abstract: Disclosed is a low gloss black polyimide film produced from a soluble black polyimide resin composition capable of realizing matte by surface transfer of a support film, without addition of a matting agent. Also provided is a black polyimide film including a stress canceling resin layer and having no curl or distortion. The black polyimide film includes: a stress canceling resin layer; a support film; and a black polyimide resin layer coated on the support film in a flexible manner, wherein low gloss is realized without addition of a matting agent, and the stress canceling resin layer for residual stress cancellation of the black polyimide resin layer is provided on the other surface of the support film.