chemistry

Hydroperoxide

Hydroperoxide is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hydroperoxide rather than just read about it. In short: Hydroperoxides or peroxols are compounds of the form ROOH, where R stands for any group, typically organic, which contain the hydroperoxy (also known as perhydroxyl) functional group (−OOH). Hydroperoxide also refers to the hydroperoxide anion (−OOH) (also known as perhydroxyl anion) and its salts, and the neutral hydroperoxyl radical (•OOH) consist of an unbound hydroperoxy group.

Key takeaways

Hydroperoxide belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hydroperoxide to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hydroperoxide from memory before moving on to harder problems.

Reference excerpt

Hydroperoxides or peroxols are compounds of the form ROOH, where R stands for any group, typically organic, which contain the hydroperoxy (also known as perhydroxyl) functional group (−OOH). Hydroperoxide also refers to the hydroperoxide anion (−OOH) (also known as perhydroxyl anion) and its salts, and the neutral hydroperoxyl radical (•OOH) consist of an unbound hydroperoxy group. When R is organic, the compounds are called organic hydroperoxides. Such compounds are a subset of organic peroxides, which have the formula ROOR. Organic hydroperoxides can either intentionally or unintentionally initiate explosive polymerisation in materials with saturated chemical bonds.

Properties The O−O bond length in hydroperoxides is about 1.45 Å. The R−O−O angles (R = H, C) are about 110° (water-like). Characteristically, the C−O−O−H dihedral angles are about 120°. The O−O bond is relatively weak, with a bond dissociation energy of 45–50 kcal/mol (190–210 kJ/mol), less than half the strengths of C−C, C−H, and C−O bonds. Hydroperoxides are typically more volatile than the corresponding alcohols:

tert-BuOOH (b.p. 36 °C) vs tert-BuOH (b.p. 82-83 °C) CH3OOH (b.p. 46 °C) vs CH3OH (b.p. 65 °C) cumene hydroperoxide (b.p. 153 °C) vs cumyl alcohol (b.p. 202 °C) (C6H5)3COOH (m.p. 87.5–88.5 °C) is a particularly stable example of a hydroperoxide

Miscellaneous reactions Hydroperoxides are mildly acidic. The pKa range is indicated by 11.5 for CH3OOH to 13.1 for Ph3COOH. Hydroperoxides can be reduced to alcohols with lithium aluminium hydride, as described in this idealized equation:

4 ROOH + LiAlH4 → LiAlO2 + 2 H2O + 4 ROH This reaction is the basis of methods for analysis of organic peroxides. Another way to evaluate the content of peracids and peroxides is the volumetric titration with alkoxides such as sodium ethoxide. The phosphite esters and tertiary phosphines also effect reduction:

ROOH + PR3 → OPR3 + ROH

Uses

Precursors to epoxides "The single most important synthetic application of alkyl hydroperoxides is without doubt the metal-catalysed epoxidation of alkenes." In the Halcon process tert-butyl hydroperoxide (TBHP) is employed for the production of propylene oxide. Of specialized interest, chiral epoxides are prepared using hydroperoxides as reagents in the Sharpless epoxidation.

Production of cyclohexanone and caprolactone Hydroperoxides are intermediates in the production of many organic compounds in industry. For example, the cobalt catalyzed oxidation of cyclohexane to cyclohexanone:

C6H12 + O2 → (CH2)5C=O + H2O Drying oils, as found in many paints and varnishes, function via the formation of hydroperoxides.

Hock processes

Compounds with allylic and benzylic C−H bonds are especially susceptible to oxygenation. Such reactivity is exploited industrially on a large scale for the production of phenol by the Cumene process or Hock process for its cumene and cumene hydroperoxide intermediates. Such reactions rely on radical initiators that reacts with oxygen to form an intermediate that abstracts a hydrogen atom from a weak C-H bond. The resulting radical binds O2, to give hydroperoxyl (ROO•), which then continues the cycle of H-atom abstraction.

Formation

By autoxidation The most important (in a commercial sense) peroxides are produced by autoxidation, the direct reaction of O2 with a hydrocarbon. Autoxidation is a radical reaction that begins with the abstraction of an H atom from a relatively weak C-H bond. Important compounds made in this way include tert-butyl hydroperoxide, cumene hydroperoxide and ethylbenzene hydroperoxide:

R−H + O2 → R−OOH

Auto-oxidation reaction is also observed with common ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran, and 1,4-dioxane. An illustrative product is diethyl ether peroxide. Such compounds can result in a serious explosion when distilled. To minimize this problem, commercial samples of THF are often inhibited with butylated hydroxytoluene (BHT). Distillation of THF to dryness is avoided because the explosive peroxides concentrate in the residue. Although ether hydroperoxide often form adventitiously (i.e. autoxidation), they can be prepared in high yield by the acid-catalyzed addition of hydrogen peroxide to vinyl ethers:

C2H5OCH=CH2 + H2O2 → C2H5OCH(OOH)CH3

From hydrogen peroxide Many industrial peroxides are produced using hydrogen peroxide. Reactions with aldehydes and ketones yield a series of compounds depending on conditions. Specific reactions include addition of hydrogen peroxide across the C=O double bond:

R2C=O + H2O2 → R2C(OH)OOH In some cases, these hydroperoxides convert to give cyclic diperoxides:

[R2C(O2H)]2O2 → [R2C]2(O2)2 + 2 H2O Addition of this initial adduct to a second equivalent of the carbonyl:

R2C=O + R2C(OH)OOH → [R2C(OH)]2O2 Further replacement of alcohol groups:

[R2C(OH)]2O2 + 2 H2O2 → [R2C(O2H)]2O2 + 2 H2O Triphenylmethanol reacts with hydrogen peroxide in the presence of acid to give the hydroperoxide:

(C6H5)3COH + H2O2 → (C6H5)3COOH + H2O

Naturally occurring hydroperoxides Many hydroperoxides are derived from fatty acids, steroids, and terpenes. The biosynthesis of these species is affected extensively by enzymes.

In the remote troposphere, hydrogen peroxide (H₂O₂) and methyl hydroperoxide (CH₃OOH) are among the most abundant hydroperoxides and act as reservoirs for HOx (OH + HO₂), buffering radical concentrations and tracing oxidation chemistry. Formation in the remote troposphere is dominated by peroxy-radical chemistry: HO₂ + HO₂ → H₂O₂ + O₂ and CH₃O₂ + HO₂ → CH₃OOH + O₂ Global aircraft observations during NASA's Atmospheric Tomography (ATom) mission show that their distributions reflect formation via peroxy-radical chemistry and are modulated by season and recent convection. Under atmospheric conditions, the reaction of organic peroxyl radicals (RO₂) with HO₂—an important source of ROOH—exhibits a generally negative temperature dependence, and its product branching competes with RO₂ autoxidation (isomerization) and RO₂+RO₂ channels. Many functionalized RO₂ types (for example, β-hydroxy or highly oxygenated RO₂) still lack good laboratory data on rates and products. Because of that, the predicted ROOH yields—and how they change with temperature—remain uncertain.

Inorganic hydroperoxides

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Hydroperoxide

Start with the simplest possible case. Write down what Hydroperoxide claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hydroperoxide before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hydroperoxide ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hydroperoxide

In research: Hydroperoxide appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hydroperoxide in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hydroperoxide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Food additives, Functional groups, Hydroperoxides, so understanding it makes those chapters shorter.
In everyday life: Look for Hydroperoxide outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hydroperoxide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hydroperoxide means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hydroperoxide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hydroperoxide in simple terms?

Why does Hydroperoxide matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hydroperoxide?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hydroperoxide.