| 摘要 |
Process for preparing a mixture of hydroxyl-containing di- and trisulfides, from either 2-mercaptoethanol or 3-mercaptopropanol, directly in two steps, without the formation of deleterious by products. Precise control of process conditions (a) in a first step in which the disulfide is formed, includes oxidation of mercapto-lower alkanol with a stoichiometric amount of H<u2>uO<u2>u while maintaining the pH and temperature of a relatively dilute aqueous reaction mixture within a specific narrow range; and, (b) in a second step in which a predetermined portion of the disulfide is converted substantially exclusively to the trisulfide, requires controlled heating of the reaction mixture to a temperature not to exceed 100`C. The process may be carried out in a single reaction vessel, and directly yields a preselected distribution of disulfide and trisulfide in the mixture. The mixture is especially useful as a chain terminator in the preparation of hydroxyl-terminated liquid polymers having an aliphatic polymeric backbone and sulfide linkages near the terminal portions of the polymer molecule (referred to as "HTPS" polymers). |
