Imperial College London
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Dr James A Bull

Faculty of Natural Sciences, Department of Chemistry

Reader in Synthetic Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 5811j.bull Website

 
 
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Location

 

501bMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Green:2020:10.1021/acs.oprd.9b00422,
author = {Green, S and Wheelhouse, K and Payne, A and Hallett, J and Miller, P and Bull, J},
doi = {10.1021/acs.oprd.9b00422},
journal = {Organic Process Research and Development},
pages = {67--84},
title = {Thermal stability and explosive hazard assessment of diazo compounds and diazo transfer reagents},
url = {http://dx.doi.org/10.1021/acs.oprd.9b00422},
volume = {24},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided in industry owing to concerns over their instability, exothermic decomposition and potential explosive behaviour. The stability of sulfonyl azides and other diazo-transfer reagents is relatively well understood, but there is little reliable data available for diazo compounds. This work firstly collates available sensitivity and thermal analysis data for diazo-transfer reagents and diazo compounds to act as an accessible reference resource. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC) data for the model donor/acceptor diazo compound ethyl (phenyl)diazoacetate is presented. We also present a rigorous DSC dataset with 43 other diazo compounds, enabling direct comparison to other energetic materials to provide a clear reference work to the academic and industrial chemistry communities. Interestingly, there is a wide range of onset temperatures (Tonset) for this series of compounds which varied between 75 and 160 °C. The thermal stability variation depends on the electronic effect of substituents and the amount of charge delocalisation. A statistical model is demonstrated to predict the thermal stability of differently substituted phenyl diazoacetates. A maximum recommended process temperature (TD24) to avoid decomposition is estimated for selected diazo compounds. Average enthalpy of decomposition (HD) for diazo compounds without other energetic functional groups is −102 kJ mol−1. Several diazo transfer reagents are analyzed using the same DSC protocol and found to have higher thermal stability, which is in general agreement with reported values. For sulfonyl azide reagents an average HD of −201 kJ mol−1 is observed. High quality thermal data from ARC experiments shows the initiation of decomposition for ethyl (phenyl)diazoacetate to be 60 °C , compared to 100 °C for t
AU  - Green,S
AU  - Wheelhouse,K
AU  - Payne,A
AU  - Hallett,J
AU  - Miller,P
AU  - Bull,J
DO  - 10.1021/acs.oprd.9b00422
EP  - 84
PY  - 2020///
SN  - 1083-6160
SP  - 67
TI  - Thermal stability and explosive hazard assessment of diazo compounds and diazo transfer reagents
T2  - Organic Process Research and Development
UR  - http://dx.doi.org/10.1021/acs.oprd.9b00422
UR  - https://pubs.acs.org/doi/10.1021/acs.oprd.9b00422
UR  - http://hdl.handle.net/10044/1/75419
VL  - 24
ER  -
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