A Simple and Efficient Device and Method for Measuring the Kinetics of Gas‐Producing Reactions

Abstract

We present a new device for quantifying gases or gas mixtures based on the simple principle of bubble counting. With this device, we can follow reaction kinetics down to volume step sizes of 8–12 μL. This enables the accurate determination of both time and size of these gas quanta, giving a very detailed kinetic analysis. We demonstrate this method and device using ammonia borane hydrolysis as a model reaction, obtaining Arrhenius plots with over 300 data points from a single experiment. Our device not only saves time and avoids frustration, but also offers more insight into reaction kinetics and mechanistic studies. Moreover, its simplicity and low cost open opportunities for many lab applications.

Isocyanate-Free Polyurea Synthesis via Ru-Catalyzed Carbene Insertion into the N–H Bonds of Urea

“…On the other hand, with 1,4-substituted diazo 2a some rate dependence on conversion was observed. To investigate this further with improved time resolution, kinetic experiments were undertaken to derive the rate law for both diazo 2a and 2e by monitoring the gas production of the reaction with a bubble counter . For diazo 2a , the diazo order dependence in the range of 5–10% catalyst loading was found to not clearly fit to a reaction order (Figures S16–S21).…”

“…To investigate this further with improved time resolution, kinetic experiments were undertaken to derive the rate law for both diazo 2a and 2e by monitoring the gas production of the reaction with a bubble counter. 35 For diazo 2a, the diazo order dependence in the range of 5−10% catalyst loading was found to not clearly fit to a reaction order (Figures S16−S21). We believe this to be an effect of the para substitution on the diazo, causing the electronics of one diazo moiety to be influenced by reactions at the other, thereby complicating the reaction profile.…”

Isocyanate-free Polyurea Synthesis via Ru-Catalyzed Car-bene Insertion into the N‒H Bonds of Urea

“…Incorporation of soft segments within polyurea segments is known to lead to a decrease in glass transition temperature. 28,29 Indeed, the heptyl substituted polymer 3d has the lowest Tg, and ethyl substituted diazo 3a has the highest Tg (Table 2). Furthermore, 1,3-phenylene substituted polymer 3e is observed to have an intermediate Tg of 89 °C whilst having the same molecular formula as 3a, showing that main chain connectivity can be used as an effective tool to control the material properties.…”