Abstract: This invention relates to a process for preparing polytrimethylene ether glycols or copolymers thereof by a polycondensation reaction using at least one acid catalyst, wherein the temperature of the reaction is controlled such that the average temperature during the first half of the reaction is higher than the average temperature during the second half of the reaction.

Abstract: Methods for purifying an aqueous hydrochloric acid solution waste stream having an impurity fraction comprising an initial Ti fraction, an initial S fraction and an initial Si fraction; that provide purified aqueous hydrochloric acid solutions having a final Ti fraction of less than 250 ppm, a final S fraction of less than 200 ppm, and a final Si fraction of less than 10 ppm, which may be determined with inductively coupled plasma spectroscopy. Process steps in various embodiments include sparging with an gas; mixing the sparged solution with a precipitation agent comprising a sufficient amount of an alkali earth metal salt and, optionally, a phosphoric acid source, to provide a metal salt precipitate; and mixing the initial aqueous acid solution or, optionally, the sparged aqueous acid solution, with a flocculating polymer. A preferred alkali earth metal salt is barium chloride and preferred flocculating polymers are poly(diallyldialkylammonium chloride) homopolymers and copolymers.

Abstract: This invention relates to a process for preparing polytrimethylene ether glycols or copolymers thereof by a polycondensation reaction using at least one acid catalyst, wherein the temperature of the reaction is controlled such that the average temperature during the first half of the reaction is higher than the average temperature during the second half of the reaction.