 In others, the catalyst is in the form of impregnated charcoal granules.Process flow diagrams and descriptions of the two conventional versions of the Merox process are presented in the following sections.The conventional Merox process for extraction and removal of mercaptans from liquefied petroleum gases (LPG), such as propane, butanes and mixtures of propane and butanes, can also be used to extract and remove mercaptans from light naphthas.