Benziodoxoles Stability Data

introduction

Benziodoxol(on)es are high energy compounds. Therefore having good information on their stability is important for safety reasons. They are generally more stable than the corresponding acyclic reagents, but they should nevertheless be manipulated with great care. The goal of this website is to have all stability data on a single place instead of scattered in our different publications. We will be happy to add data collected by other laboratories.

Since 10 years we are working with these compounds, we had an accident and explosion only with azidobenziodoxolone (ABX, Zhdankin reagent, see accident report below). This compound has therefore to be manipulated with outmost care. Original DSC data are also available below. We thank Dr. Régis Mondière, Jerome Cassayre, Fides Benfatti, Ms. Marylene Stempien and Mr. Tony O’Sullivan from Syngenta Crop Protection Munchwilen AG for performing these measurements. We thanks Dr. Annik Nanchen, Mr. Christian Aeby, Ms. Delphine Berset and Mr. Daniel Steiner from TÜV SÜD Schweiz AG for performing the in-depth studies on azidation reagents, and DR. MER Thierry Meyer from the group of chemical and physical safety at EPFL for his expert analysis of the data.

For other benziodoxole reagents, stability data are not yet available: all these compound should be therefore manipulated with great care.

According to their available stability data, we categorize the compounds in our laboratory as following:

Green: No compound, as all hypervalent iodine reagents are high energy compounds.

Yellow: Decomposition starts above 125 °C,  DSC peak height <50 mV and peak width > 5 °C, no shock sensitivity, no explosion reported.

Orange: Decomposition starts between 90 and 125 °C or DSC peak height is 30-200 mV or DSC peak width is 1-5 °C, no shock sensitivity, no explosion reported.

Red: Decomposition starts below 90 °C, or DSC peak height > 200 mV, or DSC peak width < 1 °C, or shock sensitive, or explosion reported.

Warning sign: Accident has occurred.

!!The content of this site is purely informative. In no case it can replace risk/safety analysis in other laboratories by a safety specialist. The presented data are preliminary and do not constitute a full safety analysis. They therefore cannot replace in-depth safety analysis by specialized laboratories.!!

ebx-reagents

TIPS-EBX

Decomposition starts: 135 °C
DSC data: peak height: 19 mV, peak width: 10.7 °C, peak max: 198 °C, energy: 497 J/g
No shock sensitivity observed
No explosion in more than 5000 experiments

Comment: most often used EBX reagent, strong nucleophilic bases may lead to decomposition by silyl group removal

TMS-EBX

Decomposition starts: 117 °C
DSC data: peak height: 27 mV, peak width: 9.5 °C, peak max: 155 °C, energy: 596 J/g
No shock sensitivity observed
No explosion in more than 500 experiments

Comment: sensitive to nucleophilic bases, as the silyl group is very easy to remove. Some batches decomposed in presence of bases, but never with explosive behavior

EBX

Decomposition starts: -20 °C
DSC data: not determined
No explosion in more than 200 experiments

Comment: unstable compound, needs to be generated in situ.

Me-EBX

Decomposition starts: 97 °C
DSC data: peak height: 28 mV, peak width: 9.2 °C, peak max: 148 °C, energy: 697 J/g
No shock sensitivity observed
No explosion in more than 100 experiments

tBu-EBX

Decomposition starts: 158 °C
DSC data: peak height: 15 mV, peak width: 10.6 °C, peak max: 195 °C, energy: 1066 J/g
No shock sensitivity observed
No explosion in more than 30 experiments

C14H29-EBX

Decomposition starts: 115 °C
DSC data: peak height: 10 mV, peak width: 16 °C, peak max: 147 °C, energy: 485 J/g
No shock sensitivity observed
No explosion in more than 30 experiments

Cl(CH2)3-EBX

Decomposition starts: 138 °C
DSC data: peak height: 18 mV, peak width: 16 °C, peak max: 151 °C, energy: 585 J/g
No shock sensitivity observed
No explosion in more than 30 experiments

HO(CH2)5-EBX

Decomposition starts: 124 °C
DSC data: peak height: 11 mV, peak width: 15 °C, peak max: 155 °C, energy: 438 J/g
No shock sensitivity observed
No explosion in more than 30 experiments

N3(CH2)2-EBX, JW-RF-010

Decomposition starts: 105 °C
DSC data: peak height: 540 mV, peak width: 1.2 °C, peak max: 129 °C, energy: 1927 J/g
No shock sensitivity observed
No explosion in more than 200 experiments

Ph-EBX

Decomposition starts: 113 °C
DSC data: peak height: 11 mV, peak width: 17 °C, peak max: 149 °C, energy: 559 J/g
No shock sensitivity observed
No explosion in more than 300 experiments

CF3-TIPS-EBX

Decomposition starts: 140 °C
DSC data: peak height: 8 mV, peak width: 50 °C, peak max: 226 °C, energy: 342 J/g
No shock sensitivity observed
No explosion in more than 500 experiments

other-benziodoxole-reagents

ABX, Zhdankin reagent

Decomposition starts: 90 °C
DSC data1 (pdf), DSC data2 (excel) : peak height: 132 mV (78 W/g), peak width: 0.9 °C, peak max: 127 °C, energy: 1770 J/g
Shock Sensitive. Confirmed by Fallhammer test, > 1 J (exact value too small to be determined)
Friction Sensitive: positive for a friction load of 360 N in Alox plate
Spark ignition successful (see video)
Explosion! About 3 in 700 experiments, one resulting in injury. Accident Report.

Comment: Highly useful and popular compound for azidation. Due to high hazard, should be manipulated with extreme care and in small quantities.

tBu-ABX

Decomposition starts: 98 °C
DSC data: peak height: 74 W/g, peak width: 0.7 °C, peak max: 139 °C, energy: 1440 J/g
Shock Sensitive. Confirmed by Fallhammer test, > 2 J
Friction Sensitive: negative for a friction load of 360 N in Alox plate
No explosion in about 50 experiments.

Comment: Slightly more stable derivative of Zhdankin reagent with similar reactivity and higher solubility in organic solvents.

ABZ

Decomposition starts: 143 °C, 268 °C
DSC data: peak height: 25 and 1 W/g, peak width: 1.2 and 37.7 °C, peak max: 159 and 308 °C, energy: 965 and 380 J/g
Shock Sensitive. Confirmed by Fallhammer test, > 5 J
Friction Sensitive: negative for a friction load of 360 N in Alox plate
No explosion in about 100 experiments.

Comment: Most stable analogue of Zhdankin reagent, with only few residual shock sensitivity. Comparable reactivity in photoredox and metal catalysis, but thermal initiation requires higher temperature. Solubility limited in some organic solvents. For a detailed discussion, see: ChemRxiv

ADBX

Decomposition starts: 107 °C
DSC data: peak height: 10 mV, peak width: 19 °C, peak max: 134 °C, energy: 843 J/g
No shock sensitivity. Confirmed by hammer test.
No explosion in more than 500 experiments

Comment: Surprising strong effect on safety profile of replacing carboxy group. Should be used whenever possible for azidation.

CBX

Decomposition starts: 135 °C
DSC data: peak height: 250 mV, peak width: 2 °C, peak max: 152 °C, energy: 571 J/g
No shock sensitivity observed
No explosion in more than 500 experiments

CDBX

Decomposition starts: 120 °C
DSC data: peak height: 45 mV, peak width: 10 °C, peak max: 133 °C, energy: 543 J/g
No shock sensitivity observed
No explosion in more than 100 experiments

HO-BX

Decomposition starts: 205 °C
DSC data: 135 mV, peak width: 0.5 °C, peak max: 229 °C, energy: 597 J/g
No shock sensitivity observed
No explosion in more than 500 experiments

Comment: Detailed safety studies reported in Org. Proc. Res. Dev. 2013, 17, 318. Large temperature safety margin but still high explosive potential.

NMe-C3-IndoleBX

Decomposition starts: 150 °C
DSC data: 18 mV, peak width: 3.7 °C, peak max: 183 °C, energy: 282 J/g
No shock sensitivity observed
No explosion in more than 100 experiments

NMe-C3-PyrroleBX

Decomposition starts: 190 °C
DSC data: 41 mV, peak width: 1.8 °C, peak max: 215 °C, energy: 574 J/g
No shock sensitivity observed
No explosion in more than 20 experiments

NMe-C2-PyrroleBX

Decomposition starts: 165 °C
DSC data: 27 mV, peak width: 3.3 °C, peak max: 203 °C, energy: 546 J/g
No shock sensitivity observed
No explosion in more than 20 experiments