| abstract |
A process for removing precursors, such as low boiling alkyl glycols (e.g., ethylene glycol and/or 1,2-propylene glycol), to undesirable color forming acetal impurities (e.g., 1,3-dioxolane and 4-methyl-1,3-dioxolane) from technical grade 1,4-butanedio1/2-methyl-1,4-butanediol mixtures and the like by distillative topping of the diol mixture prior to ring closing cyclization to corresponding tetrahydrofuran/3-methyl tetrahydrofuran mixture and subsequent polymerization to polytetramethylene glycol ether polymers. Such a process is useful to produce THF and PTMEG having an APHA color index of nearly zero. |