Henry Rzepa's Blog Chemistry with a twist

September 28, 2020

Blasts from the past: a snapshot of online content in chemistry, ~1994-1998.

Filed under: Historical — Henry Rzepa @ 2:03 pm

With universities around the world having to very rapidly transition to blended learning (a mixture of virtual and face-2-face experiences) with a very large component based on online materials, I thought it might be interesting to try to give one snapshot of when the online experience started to happen in chemistry.


September 7, 2020

The Willgerodt-Kindler reaction. Completing the Box set.

Filed under: reaction mechanism — Henry Rzepa @ 10:14 am

These four posts (the box set) set out to try to define the energetics for a reasonable reaction path for the Willgerodt-Kindler reaction. The rate of this reaction corresponds approximately to a free energy barrier of ~30 kcal/mol. Any pathway found to be >10 kcal/mol at its highest point above this barrier was deemed less probable. The first three efforts at defining such pathways all gave such a result. Here I try a fourth pathway in search of the hitherto elusive appropriately low energy barrier.


September 2, 2020

High-performance polythioesters with high chemical recyclability.

Filed under: Interesting chemistry — Henry Rzepa @ 2:18 pm

Here I investigate a recent report[1] of a new generation of polyesters with the intrinsic properties of high crystallinity and chemical recyclability. The latter point is key, since many current plastics cannot be easily recycled to a form which can be used to regenerate the original polymer with high yield. Here I show some aspects of this fascinating new type of polymer.



  1. C. Shi, M.L. McGraw, Z. Li, L. Cavallo, L. Falivene, and E.Y. Chen, "High-performance pan-tactic polythioesters with intrinsic crystallinity and chemical recyclability", Science Advances, vol. 6, pp. eabc0495, 2020. http://dx.doi.org/10.1126/sciadv.abc0495

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