Abstract: The invention relates to a method of preparing a stationary silica phase for the purpose of packing a chromatographic column intended for the liquid-phase separation of components. There are thus effected a first grafting with functional groups of the amine type, a complete hydrolysis of the stationary phase so grafted, and finally a further grafting with functional groups of the alkyl type, optionally substituted. A chromatographic column packed with the stationary silica phase can be used to separate the constituents of a petroleum product.

Abstract: A process and apparatus for blow-molding hollow bodies in a mold having half-molds which are closed along a mold joint during blow molding and are laterally displaced with respect to one another to open the mold for removal of the formed hollow body. The half-molds are shaped to form a concave bottom on the hollow body and when the half-molds are opened they impose a translation movement on the hollow body. A plug is formed at the bottom of the hollow body during molding which plug is seized by pincers prior to the opening of the mold such that the hollow body is supported by the pincers during mold opening. The pincers are displaced during mold opening, in translation parallel to the plane of the mold joint, over a distance at least equal to that imposed on the hollow body by the half-molds during opening of the mold.