Home Podcasts THMG118 – Functional Groups: Organic Peroxides

THMG118 – Functional Groups: Organic Peroxides


In this episode, Bob and Mike talk about the organic peroxides functional group.

Complete Show Notes

3:45 What Are Organic Peroxides?

  • Any organic compound having two oxygen atoms that are bonded together – not the double bond we see in compounds like O2, but as a single O-O bond
  • Oxygen doesn’t really like O-O bonds, so it becomes unstable – that instability it what distinguishes peroxides from organic peroxides
  • Peroxides have two oxygens attached to each other in a single bond, but oxygen really wants to bond twice – as a result, it combines with other things
  • As a general rule of thumb, these carbon-based things tend to be flammable – at the very least, they’re a fuel
  • This doesn’t mean they can’t burn and cause problems, though
  • Organic peroxides are far worse than peroxides because there’s a fuel right next to the oxygen – when they decompose, they can instantly react with the available oxygen
  • They also break down at really low temperatures, which doesn’t help the situation

10:15 How Do We Use Organic Peroxides?

  • Used as accelerators in chemical reactors, activators, and catalysts
  • To turn a raw material into a finished product, you have to change it through a chemical reaction of some type
  • The instability of organic peroxides and their desire to react means they’re great at helping make those changes in industry
  • When trying to combine large compounds, organic peroxides are great at cross-linking
  • They can also create curing agents, hardeners, initiators, and promoters – you’ll find them in almost any industry as a result

14:20 How Are Organic Peroxides Transported?

  • Rail cars: DOT class 103, 104, 105, 109, 111, 112, 114, 115, and 120
  • Cargo tanks: MC 307, MC 310, MC 311, MC 312, DOT 407, and DOT 412 – only cargo tank motor vehicles with a tank pressure of at least 172 kPa (25 psig) are authorized

15:55 Transportation in Portable Tanks

  • Transported via DOT 51, DOT 57, and IM 101
  • These tanks and numbers correspond to the types of tanks the DOT has created specifications for – for example, DOT 51 is a steel tank, and under that specification it has to meet certain requirements
  • Portable tanks must be designed for a test pressure of at least 0.4 MPa (4 bar) and outfitted with temperature-sensing devices (vacuum relief devices may also be used)
  • Pressure relief devices must operate at pressures determined by both the properties of the hazardous material and the construction characteristics of the portable tank
  • Fusible elements aren’t allowed in the shell – can also be found in Jerrica boxes and composite packaging with a plastic inner receptacle

19:50 The Globally Harmonized System for Hazard Communication (GHS)

  • Classification and labeling of chemicals – 7 categories for organic peroxides
  • Type A: an organic peroxide as packaged that can detonate or deflagrate rapidly
  • Type B: an organic peroxide as packaged that doesn’t detonate or deflagrate rapidly, but is capable of undergoing a thermal explosion
  • Type C: an organic peroxide as packaged that possesses explosive properties but will not denote, deflagrate, or thermally explode
  • Types D-F: organic peroxides that have shown hazards (such as partial detonation) when tested in a laboratory, but do not possess these hazards as packaged

21:55 Storing Organic Peroxides and Self-Accelerating Decomposition Temperature (SADT)

  • Most organic peroxides are stored in some kind of chilling unit at around 20 degrees Fahrenheit below the SADT
  • SADT is the lowest temperature at which self-accelerating decomposition may occur
  • As temperatures increase, so does the rate at which an organic peroxide will break down – this breakdown reaction is very exothermic, so it gives off heat in the process
  • Heat then breaks down the surrounding organic peroxides and starts a chain reaction that there’s no coming back from if the temperature is too high
  • When an organic peroxide (a fuel) mixes into our oxygen, there’s the potential for a reaction that can happen so fast that it deflagrates or detonates
  • Shock waves off a detonation of an organic peroxide can get up to 9,000 m/s – the better or stronger the container is, the higher the pressure builds up, which leads to bigger or faster reactions
  • This becomes an issue during transportation incidents where the ability to chill the organic peroxide is reduced or eliminated, the time it takes to transport the organic peroxide is underestimated or delayed, or if the transportation vessel is involved in a fire

27:10 Approaching and Handling an Organic Peroxide Transportation Incident

  • We need to obtain the temperature of the product and a pressure reading inside the vessel (if it has a temperature gauge)
  • Comparing that information to the SADT can help us determine the next step and what we need to know about that chemical
  • You can find more information on organic peroxides in several places:
    • CAMEO
    • PubChem
    • ChemicalBook
    • Safety data sheets (SDS) – these usually provide the SADT, which is the most important thing we need to know about an organic peroxide

37:10 Bonus Organic Peroxide Nuggets

  • Organic peroxides will whiten your fingers if you touch them
  • Organic peroxides also have a bleaching effect
  • Organic peroxides defeat our oxidizer (KI) and pH papers by whitening them
  • Organic peroxides are lighter than water
  • Water is the recommended cooling/fire extinguishing agent for organic peroxides – you won’t put the fire out, but you’ll slow it down
  • Organic peroxides release hydrocarbons and alcohols when burning

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