摘要 |
<p>The invention provides a process that can be used for producing a bis-glycolate ester of 5-sulfo isophthalate metal salt. The process comprises contacting a 5-sulfo isophthalate a metal salt or a dialkyl ester of 5-sulfo isophthalate metal salt, in the presence of a catalyst, with a glycol. The catalyst comprises (1) a titanium compound, a solubility promoter, a phosphorus source, and optionally a solvent, (2) a titanium compound, a complexing agent, a phosphorus source, and optionally a solvent, a sulfonic acid, or combinations thereof, or (3) combinations of (1) and (2). The solubility promoter can be selected from the group consisting of ortho silicates, ortho zirconates and combinations thereof. The phosphorus source is selected from the group consisting of a phosphonic acid, a phosphinic acid, a phosphine, and combinations of two or more thereof. The complexing agent can be selected from the group consisting of hydroxycarboxylic acids, aminocarboxylic acids, and combinations thereof. The invention also provides a process that can be used for producing a cationic dyeable polyalkylene terephthalate. The process comprises contacting a mixture, in the presence of an esterification or transesterification catalyst, with a glycol in which the mixture comprises the bis-glycolate ester of 5-sulfo isophthalate metal salt produced by the process disclosed above and either a terephthalate acid or a dialkyl terephthalate.</p> |