Acetone peroxide

Acetone peroxide

Names
IUPAC names 3,3-Dimethyl-1,2-dioxacyclopropane (monomer) 3,3,6,6-Tetramethyl-1,2,4,5-tetraoxane (dimer) 3,3,6,6,9,9-Hexamethyl-1,2,4, 5,7,8-hexaoxacyclononane (trimer) 3,3,6,6,9,9,12,12-Octamethyl-1,2,4, 5,7,8,10,11-octaoxacyclododecane (tetramer)
Other names Triacetone Triperoxide Peroxyacetone Mother of Satan
Identifiers
CAS Number	17088-37-8 N
ChemSpider	3582942 Y
Jmol 3D model	dimer: Interactive image trimer: Interactive image
PubChem	536100
InChI InChI=1S/C9H18O6/c1-7(2)10-12-8(3,4)14-15-9(5,6)13-11-7/h1-6H3 Y Key: ZTLXICJMNFREPA-UHFFFAOYSA-N Y InChI=1/C9H18O6/c1-7(2)10-12-8(3,4)14-15-9(5,6)13-11-7/h1-6H3 Key: ZTLXICJMNFREPA-UHFFFAOYAS
SMILES dimer: CC1(C)OOC(C)(C)OO1 trimer: CC1(C)OOC(C)(C)OOC(C)(C)OO1
Properties
Chemical formula	C6H12O4 (dimer) C9H18O6 (trimer) C12H24O8 (tetramer)
Molar mass	148.157 g/mol (dimer) 222.24 g/mol (trimer)
Appearance	White crystalline solid
Melting point	91 °C (196 °F; 364 K)
Boiling point	97 to 160 °C (207 to 320 °F; 370 to 433 K)
Solubility in water	insoluble
Vapor pressure	{{{value}}}
Explosive data
Shock sensitivity	High / moderate when wet
Friction sensitivity	High / moderate when wet
Detonation velocity	5300 m/s 17,384 ft/s 3.29 miles per second
RE factor	0.83
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Acetone peroxide (triacetone triperoxide, peroxyacetone, TATP, TCAP) is an organic peroxide and a primary high explosive. It takes the form of a white crystalline powder with a distinctive bleach-like odor.

It is susceptible to heat, friction and shock. The instability is greatly altered by impurities, including its own oligomers. It is not easily soluble in water.

History

Acetone peroxide was discovered in 1895 by Richard Wolffenstein. He was the first chemist to use inorganic acids as catalysts. He was also the first researcher to receive a patent for using the peroxide as an explosive compound. In 1900 Bayer and Villiger described in the same journal the first synthesis of the dimer and also described use of acids for the synthesis of both peroxides. Information about these procedures including the relative proportions of monomer, dimer, and trimer is also available in an article by Milas and Golubović.

Chemistry

"Acetone peroxide" most commonly refers to the cyclic trimer TCAP (tri-cyclic acetone peroxide, or tri-cyclo, C₉H₁₈O₆) obtained by a reaction between hydrogen peroxide and acetone in an acid-catalyzed nucleophilic addition:

The dimer (C₆H₁₂O₄) and open monomer are also formed, but under proper conditions the cyclic trimer is the primary product. A tetrameric form was also described.

In mildly acidic or neutral conditions, the reaction is much slower and produces more monomeric organic peroxide than the reaction with a strong acid catalyst. Due to significant angle strain of the chemical bonds in the dimer and especially the monomer, they are even more unstable than the trimer.

At room temperature, the trimeric form slowly sublimes, reforming as larger crystals of the same peroxide.

Acetone peroxide is one of the few high explosives not containing nitrogen. This is one reason it has become popular with terrorists, as it can pass through scanners designed to detect nitrogenous explosives.

TCAP generally burns when ignited, unconfined, in quantities less than about 4 grams. More than 4 grams will usually detonate when ignited; smaller quantities might detonate when even slightly confined. Completely dry TCAP is much more prone to detonation than the fresh product still wetted with water or acetone. The oxidation that occurs when burning is:

2 C
₉H
₁₈O
₆ + 21 O
₂ → 18 H
₂O + 18 CO
₂

Theoretical examination of the explosive decomposition of TCAP, in contrast, predicts "formation of acetone and ozone as the main decomposition products and not the intuitively expected oxidation products." This result is in good agreement with the results of 60 years of the study of controlled decompositions in various organic peroxides. It is the rapid creation of gas from a solid that creates the explosion. Very little heat is created by the explosive decomposition of TCAP. Computational analysis suggests that TCAP decomposition as an entropic explosion. However, this hypothesis has been challenged as not conforming to actual measurements.

The high sensitivity to shock, heat and friction are due to the instability of the molecule. Big crystals, found in older mixtures, are more dangerous, as they are easier to shatter—and initiate—than small ones.

Synthesis of tri-cyclic acetone peroxide.

Due to the low cost and ease with which the precursors can be obtained, acetone peroxide can be manufactured by those without the resources needed to manufacture or buy more sophisticated explosives. When the reaction is carried out without proper equipment the risk of an accident is significant.

There is a common myth that the only "safe" acetone peroxide is the trimer, made at low temperatures:

The mixture must be kept below 10 degrees Celsius. If the crystals form at this temperature, it forms the isomer called tricycloacetone peroxide, which is relatively stable and safe to handle. If the crystals form above this temperature, the dimeric form, called dicycloacetone peroxide. This isomer is much more unstable, and could go off at the touch, making it not safe enough to be considered a practical explosive. As long as the temperature is kept below 10 degrees Celsius, then there is little to worry about.

The trimer is the more stable form, but is not much more so than the dimer. All forms of acetone peroxide are sensitive to initiation. Organic peroxides are sensitive, dangerous explosives; due to their sensitivity they are rarely used by well funded militaries. Even for those who synthesize explosives as a hobby there are far safer explosives with syntheses nearly as simple as that of acetone peroxide.

Acetone peroxide is commonly combined with nitrocellulose by dissolving the nitrocellulose in acetone and then mixing in the acetone peroxide and letting it dry, which results in a mixture that is both more stable and somewhat more powerful than acetone peroxide by itself. This mixture is commonly referred to as APNC.

Tetrameric acetone peroxide is more chemically stable (heating to 120 °C for 4 hours), although it is still a very dangerous primary explosive. It can be prepared using tin(IV) chloride (without acid present) as a catalyst with up to 40% yield if a radical inhibitor such as hydroquinone, or a chelator such as EDTA is added.

Tetrameric acetone peroxide

Acetone peroxide evaporates 6.5% in 24 hours at 14–18 °C. In open air at 25 °C it has a loss by sublimation of 68.6% in 14 days. Many accidents have resulted from the fact that acetone peroxide detonates due to sublimation. Keeping it wet stops the sublimation and can prevent this type of accident.

Industrial occurrence

Acetone peroxides are common and unwanted by-products of oxidation reactions, such as those used in phenol syntheses. Due to their explosivity, they are hazardous. Numerous methods are used to reduce their production—shifting the pH to more alkaline, adjusting the reaction temperature, or adding a soluble copper(II) compound.

Acetone peroxide and benzoyl peroxide are used as flour bleaching agents to bleach and "mature" flour.

Ketone peroxides, including acetone peroxide, methyl ethyl ketone peroxide, and benzoyl peroxide, find applications as initiators for polymerization reactions of e.g. silicone or polyester resins, often encountered when making fiberglass-reinforced composites. For these uses, the peroxides are typically in the form of a dilute solution in an organic solvent, though even commercial products with higher concentrations of organic peroxides can form crystals around the lid when older, making the can shock-sensitive. Methyl ethyl ketone is more common for this purpose, as it is stable in storage.

Accidental byproduct

Acetone peroxide can also occur accidentally, when suitable chemicals are mixed. For example, when methyl ethyl ketone peroxide is mixed with acetone while making fiberglass composites, and left to stand for some time, or when a mixture of peroxide and hydrochloric acid from printed circuit board etching is mixed with waste acetone from cleaning the finished board and allowed to stand. While amounts obtained this way are typically much smaller than from intentional production, they are also less pure and prepared without cooling, and hence very unstable.

It is also a hazardous by-product of isosafrole oxidation in acetone, a step in the synthesis of MDMA.

Use in improvised explosive devices

See also: Improvised explosive device

Acetone peroxide has earned the nickname "Mother of Satan", for its high susceptibility to accidental detonation, but is used by terrorists due to the low cost and ease with which the precursors can be obtained; and because it is one of the few high explosives not containing nitrogen, so can pass undetected through scanners designed to detect nitrogenous explosives.

The precursor, Hydrogen Peroxide, which acts an explosive in itself when highly concentrated, as well as when used to make the primary explosive Tri-Acetone Tri-Peroxide (TATP), has been used in a number of terror attacks. It was for instance used in the November 2015 Paris attacks.

Several methods can be used for trace analysis of TATP, including gas chromatography/mass spectrometry (GC/MS) and high performance liquid chromatography/mass spectrometry (HPLC/MS).

External links

• ChemSub Online: Acetone peroxide – Triacetone triperoxide.