Abstract: The subject of the present invention is a process for preparing acrolein by dehydration of glycerin, characterized in that the dehydration is carried out in the presence of a catalyst comprising mainly a compound in which protons in a heteropolyacid are exchanged at least partially with at least one cation selected from elements belonging to Group 1 to Group 16 of the Periodic Table of Elements. The process according to the invention permits to obtain acrolein at higher yield.

Abstract: The process for the distillation of a gas mixture comprising (meth)acrylic acid obtained from the gas-phase oxidation of at least one (meth)acrylic acid precursors is improved through the use of coupled distillation columns. In a first column, the gaseous mixture is dehydrated while in a second column, the dehydrated gaseous mixture is distilled into product, overhead and bottoms streams.

Abstract: Solutions such as for example groundwater, drinking water, extracting solutions and effluents contaminated with metals, radioactive species and organics, singly or in combination, are treated by first removing undesirable oxidizing agents from the contaminated solution. Then the contaminated solution is separately treated with aqueous solutions of ferrous sulfate and hydroxide, which precipitate substantially all of the contaminants. Next, the precipitate is treated with a flocculant and/or a coagulant to form an easily dewaterable and separable solid. The solid contaminants are readily removed from the cleansed solution. The process utilizes a novel combination of steps which maximizes contaminant removal, minimizes waste volume, and produces a recyclable solution and a manageable waste stream. The preferred hydroxide solutions are sodium hydroxide, calcium hydroxide, and ammonium hydroxide.

Abstract: A method for removing and stabilizing in-situ soluble heavy metal contaminants in land formations which comprises introducing into said formation an aqueous remediation solution comprising naturally-occurring ions present in said formation and remediation ions. The remediation solution selectively solubilizes and mobilizes the heavy metal contaminants into solution while substantially suppressing the displacement of said naturally-occurring ions from said formation. The method is effective with heavy metals which exist in both anionic and cationic form, and may be used to treat land formations below the surface to reduce soluble heavy metal contamination to a few parts per billion.