Controlled temperature process for making 2,2'-oxodisuccinates useful as laundry detergent builders

Abstract From the Canadian patent

IMPROVED, CONTROLLED TEMPERATURE PROCESS FOR MAKING 2,2'-OXODISUCCINATES USEFUL AS, LAUNDRY DETERGENT BUILDERS ABSTRACT OF THE DISCLOSURE, High yields of 2,2'-oxodisuccinate are secured by reacting maleate and malate in aqueous alkaline media containing mixtures of particular divalent (e.g. Ca2+) and solubilizing monovalent (e.g. Na+) cations. In a preferred embodiment the process has, both an elevated temperature primary reaction step and one or more low temperature maturation steps. Yields of 2,2'-oxodisuccinate are increased and formation of fumarate by-product is minimized. Malate useful as a starting-material in the process is also, provided near-quantitatively by heating an aqueous …