On October 27, 2020, Lin, Binhong; Jadrich, Caleb N.; Pane, Vince E.; Arrechea, Pedro L.; Erdmann, Tim; Dausse, Charles; Hedrick, James L.; Park, Nathaniel H.; Waymouth, Robert M. published an article.Category: amides-buliding-blocks The title of the article was Ultrafast and Controlled Ring-Opening Polymerization with Sterically Hindered Strong Bases. And the article contained the following:
The controlled anionic ring-opening polymerization of lactones and siloxanes is carried out in continuous-flow reactors. Anionic ring-opening polymerization of cyclic esters with strong, soluble bases such as potassium tert-butoxide (KOtBu) is typically performed as batch reactions, leading to broad dispersity and poor control over the mol. weight (Mn) mainly because of transesterification reactions. Although reactions with strong bases give rise to “uncontrolled” polymerizations, a variety of transition metal-based and organocatalysts have been developed with the goal of reliably controlling the dispersity and Mn. Herein, we show that the rapid mixing and short residence times accessible with a continuous-flow apparatus can enable the controlled polymerization of low-reactivity monomers such as δ-valerolactone and ε-caprolactone on millisecond time scales using a base [such as KOtBu or potassium bis(trimethylsilyl)amide (KHMDS)] in conjunction with a primary alc. These reactions exhibit characteristics capable of producing narrow dispersity with predictable mol. weights and can rapidly generate well-defined block copolymers with residence times below 0.1 s. The experimental process involved the reaction of 1,3-Diphenylurea(cas: 102-07-8).Category: amides-buliding-blocks
The Article related to ultrafast controlled ring opening polymerization sterically hindered strong base, Chemistry of Synthetic High Polymers: Ring-Opening and Other Polymerizations and other aspects.Category: amides-buliding-blocks
Referemce:
Amide – Wikipedia,
Amide – an overview | ScienceDirect Topics