Questions tagged [radicals]

Radicals are highly reactive species, that have one or more unpaired electrons. Whether a species has unpaired electron(s) can be experimentally determined through electron pair resonance spectroscopy. Radicals are paramagnetic. This tag should be applied to questions that involve free radicals as a species or radicals in reactions and their mechanisms.

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Mechanism of Cu Catalyzed reaction between Benzoic acid with DMF

I'm looking for the mechanism of this reaction that I have stumbled upon. It is believed to be a radical reaction and I can kinda see that but I'm not convinced that I can understand all of the steps, ...
GabrielAlx's user avatar
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Potassium Ethoxide Synthesis: Does the Reaction Involve Radical Processes?

Can Potassium Ethoxide be obtained by reacting the alcohol with metallic potassium? Considering that potassium, as a group one metal, has only one valence electron, would this reaction therfore ...
Re7's user avatar
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Can Sodium atom (Na not Na+) be considered a free radical?

By definition "Free radical is a chemical species that has a single unpaired electron in the outermost orbit". Sodium atom also has a unpaired electron in outermost shell and it is also ...
Afzaal's user avatar
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Confusion in Free Radical Reactions with alkenes

I was reading the free radical reactions, therein I saw two almost same(atleast that's what i think) but forming different products. First, we have cyclohexene reacting with Br2 in presence of ...
PinkAura's user avatar
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Can I Detect Hydroxyl Radicals Using Methylene Blue Spectrophotometry?

I am going to be pulsing radiation into a chamber containing a solution of water and both ferric and ferrous iron. The irradiation event should cause a Fenton reaction to ensue and I'd like to trap ...
Bon's user avatar
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1 answer
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Any method for measuring hydroxyl and hydroperoxyl radicals in water?

I am looking to irradiate water containing some amounts of iron and would like to measure the amount of hydroperoxyl and hydroxyl radicals produced in real time as a result of the irradiation. Is ...
Bon's user avatar
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2 answers
237 views

Ozone formation

I have read about the formation of natural atmospheric ozone on Wikipedia, where it is claiming that the ozone creation step requires an extra molecule in order to conserve momentum and energy: $$\ce{...
user21820's user avatar
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Order of radical dimerization ability

In a question I came across recently, it was asked to arrange the following radicals in the ascending order of dimerization ability. I have read about the triphenylmethyl radical undergoing Gomberg ...
Cyclopropanol's user avatar
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What is the free radical mechanism of Ruff's degradation?

There are very few resources on the mechanism of Ruff's degradation of carbohydrates, which adds $\ce{Br2}$ to oxidize aldehydic group of reducing sugars like glucose to carboxylic acid and then adds ...
user21737217's user avatar
3 votes
1 answer
196 views

Free-radical addition of bromine to alkene

If light and radical initiators are present, radical addition of $\ce{HBr}$ to alkenes takes place and outcompetes electrophilic addition of $\ce{HBr}$ to alkenes. Why isn't a similar thing same ...
Silenus's user avatar
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Why is the phrase "abstraction" used in radical reactions? [closed]

Often, I see the phrase "abstraction" used to describe certain radical reactions. Why is this specific term "abstraction" used in the case of radicals? This may be more of a ...
Eric's user avatar
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+M or -I for chlorine? Major product in free radical chlorination and bromination of 2-chloropropane?

Is the +M or -I effect more dominant in when an alkyl (mono)halide is subject to free radical chlorination/bromination? For example what will be the major product in case of free radical (mono)...
Valoruz's user avatar
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How does tetraethyl lead prevent knocking?

My understanding of knocking is that in a spark ignition engine as the fuel is being compressed it heats up. The heat causes some of the oxygen to break up into oxygen radicals the $\ce{O^.}$ ...
Q the Platypus's user avatar
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1 answer
101 views

Radicals, reaction intermediate, activated complex [closed]

I'm really confused about those three concepts: radicals, reaction intermediate, activated complex. First of all, in my course we have seen radicals in the context of chain radical reactions. But ...
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Radical chain reactions

I have some questions about radical chain reactions. Let's take an example: And here are my questions: How can we define in the above case at which level the reaction 2) is located (initiation or ...
c.leblanc's user avatar
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Why are free radicals not considered as positive or negative even though they usually have 1 excess electron? [closed]

Same as the question, I looked up radicals etc, and could see that methyl radical or phenyl radical had 1 extra electron that would have been a bonding electron normally. However it is not considered ...
amspsingh04's user avatar
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Monochlorination of (R)-2-chlorohexane: Number of possible chiral dichloro products

How many possible chiral dichloro products can be formed when (R)-2-chlorohexane reacted with one equivelent of $\ce{Cl2}$ in the presence of UV radiation (monochlorination only)? $$\ce{C6H11Cl + Cl2 -...
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PVP-iodine and octenidine can stain skin purple, does the reaction create iodine radicals?

In this paper it is mentioned that ... octenidine can release iodine radicals from the PVP complex, resulting in a tissue irritation as well as strong brown to violet discolouration in the border ...
Michael Paul's user avatar
3 votes
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70 views

Calculate frequency dose from different light intensities

The quantum yield for homolytic O-O cleavage of (CH$_3$)$_3$COOC(CH$_3$)$_3$ at $266$ nm is $0.21$. In one experiment, a pulsed laser of this wavelength was used to induce the formation of t-butoxyl ...
katara 's user avatar
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Two wavelength photo-initiators?

Not a chemist so I hope you'll forgive any amateur mistakes. I found an overview of 3D printing resin photo-initiators here: https://pubs.acs.org/doi/10.1021/acsapm.8b00165#tbl1 All these activate ...
Stefan's user avatar
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The major product of radical halogenation: Why is it a halogen attached to a primary carbon and not a tertiary carbon in the given example?

There's this problem that I saw in my Organic Chemistry book: The reaction between $\ce{(CH3)3CH}$ and $\ce{Cl2}$ forms two products: $\ce{(CH3)2CHCH2Cl}$ (63%) and $\ce{(CH3)3CCl}$ (37%). Why is the ...
blair's user avatar
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3 votes
2 answers
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Why are radicals considered electron deficient?

I have often read that radicals are electron-deficient and are therefore stabilized by things like electron-donating groups (EDGs) and hyperconjugation. However, today I learned that electron-...
Akash's user avatar
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How are antioxidants different from other compounds that contain hydroxyl group?

From my book: An antioxidant is a substance that prevents oxidation by reacting with an oxidizing agent If that's the case, why do we distinguish between antioxidants? Are all compounds containing ...
Patrick's user avatar
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1 answer
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How does Hyperconjugation stabilize a Carbon Free Radical? [closed]

I tried drawing the resonance structures but just cannot see how donating two electrons to a carbon that only needs one electron make it more stable? I stumbled upon this question asked years ago ...
Arman Ansary's user avatar
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1 answer
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Kharasch Peroxide effect with heating

From what i have learnt, kharasch Peroxide effect is only applicable for HBr. The reason for this is for the other halogens, HCl and HI the propagation steps in the radical mechanism are endothermic. ...
Sage of Seven Paths's user avatar
3 votes
1 answer
606 views

Ozone depletion with the OH radical

$\ce{OH*}$ radicals are known to deplete the ozone layer. Fill out the gaps below to complete the propagation stage: \begin{align} \ce{? + O3 &-> ? + O2}\\ \ce{? + O3 &-> ? + O2} \...
FShrike's user avatar
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1 answer
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Can uv light cause heterolytic cleavage?

All sources I've read stated that UV-light can only cause homolytic cleavage (homolytic fission), producing radicals while not mentioning whether it was possible for it to cause heterolytic cleavage ...
boop's user avatar
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1 answer
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How to name radical

The name of biradical —CO—CH2–O—CH2–CO— is Oxybis (1-oxo-2,1-ethanediyl). Why is it wrong to write 1,2-ethanediyl instead of 2,1? Thanks in advance!
Ann Ivanov's user avatar
1 vote
1 answer
289 views

Why do radical inhibitors inhibit a reaction by creating a "more stable" radical, but for monohalogenation, we WANT to form the most stable radical?

According to my notes, radical inhibitors tend to turn a more reactive radical into a less reactive radical by making it more stable. For instance, the hydroquinone reacts with a radical species, ...
BlueMagic1923's user avatar
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1 answer
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Why is carbon tetrachloride more stable than methane?

When a mixture of methane and chlorine is exposed to ultraviolet light – typically sunlight – a substitution reaction occurs and the organic product is chloromethane. However, the reaction doesn't ...
Invisible's user avatar
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1 answer
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Reaction Mechanism for a radical ring opening

I have a radical reaction which I got from an organic chemistry lecture and was drawing the possible mechanism for it. Fig 2. shows my thought process. The I is removed making a radical and ISnBu$_3$. ...
bobsburger's user avatar
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What is the reaction steps taken when producing auroral forcing?

As described in here: https://www.nasa.gov/feature/goddard/2018/sounding-rocket-mission-will-trace-auroral-winds A mixture of Trimethylaluminium, Barium and Strontium reacts and ionize in the upper ...
C-Consciousness's user avatar
2 votes
0 answers
54 views

Plotting second order reaction with different reactants

In a laser flash photolysis experiment, $\ce{C6H5NH2}$ $(C_0 = \pu{60 \mu M})$ is oxidize to its corresponding radical cations. There are three possible reaction pathways for the formation of the ...
katara 's user avatar
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2 votes
1 answer
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g-tensor and hyperfine tensor for nitroxide spin label with 15N

Does anyone know where I can find numerical data for the $g$ tensor and hyperfine tensor for a nitroxide spin label where the nitrogen-14 atom has been replaced by a nitrogen-15 atom? I'm really ...
Ben's user avatar
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Photobromination of cyclohexene

During bromination of cyclohexene in the presence of hv via free radical mechanism, there are two allylic carbons. Why does the major product have only one Br an not a Br on either side of double bond....
Niescte's user avatar
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5 votes
2 answers
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How would this reaction occur through free radical substitution?

So, I was trying to solve this through free radical substitution: (Side note, the (ac) means (aq)) The best product I managed to do/think was the following: However, according to what I've seen, it'...
Wild Chemist's user avatar
2 votes
1 answer
168 views

Bromochlorofluoromethane as a reagent in Riemer-Tiemann reaction

The reagent usually used in Riemer-Tiemann reaction is $\ce{CHCl_3 }$ however one of the variations I read used $\ce{CHFClBr}$ as a reagent. Now $\ce{CHCl_3}$ produces the $\ce{:CCl_2}$ radical using ...
Ashish's user avatar
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How to graph a second order reaction with two different reactants

In a laser flash photolysis experiment, $\ce{C6H5NH2}$ $(C_0 = \pu{60 \mu M})$ is oxidized to the corresponding radical cation. The disappearance of radical cation is monitored spectrophotometrically ...
katara 's user avatar
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3 votes
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Preferred radical attack on a polyester

My question concerns the relative stability of a radical next to an ester oxygen compared to a radical next to an ester carbonyl carbon. The stabilizing effect of the electron pairs of ether oxygen ...
Lothar Maier's user avatar
8 votes
1 answer
307 views

Is “double dot” (“··”) notation used for a double radical?

I wondered if this was a typo in the notes given to me. I haven’t come across notation like this before: Branching — steps in which number of radicals increases (can lead to explosion) $$\ce{H^. + O2 ...
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2 votes
1 answer
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Flavonoid Xanthine Oxydase Inhibitors vs Hydroxychloroquine

Regarding COVID-19 and hydroxychloroquine (HCQ), HCQ is known to increase pH in lysosomes by 1-2 orders of magnitude, and also results in lethal intracellular heme overload in parasites responsible ...
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Stabillity of ethyl, iso propyl and vinyl free radicals

Well this might seem like a dumb question but I was just wondering if any other factor would apply here as well? By simply looking at the number of hyperconjugative structures, I could easily tell ...
Prajwal Tiwari's user avatar
5 votes
1 answer
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TEMPO Radical Analogue

After investigating what makes the persistent radical TEMPO stable, I was wondering if another compound which is more feasible for my needs would be comparable to it. Would oxidizing 2,2’-dimethyl-...
Evamentality's user avatar
3 votes
1 answer
52 views

Photodissociated iodine laser and population inversion

Iodine molecules ($\ce{I2}$) can absorb in the visible region and dissociate into $\ce{2 I^.}$ radicals. One of the I atoms is in ground electronic state $\mathrm{^2P_{3/2}}$ and the other I atom is ...
S R Maiti's user avatar
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2 votes
2 answers
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Why doesn't fluorine harm the ozone layer the way chlorine and bromine do? [closed]

I don't understand the chemistry here: fluorine is a halogen too. I read that fluorine in the atmosphere readily forms HF, which is (somewhat) stable and doesn't catalytically break down ozone. But, ...
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What is the geometry of a tri-substituted methyl free radical?

My teacher explained that free radicals could have a geometry that is planar or pyramidal(tending to tetrahedral) based on whether or not it is substituted by lone-pair containing atoms. For example, $...
Desai's user avatar
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Why is gasoline consisting of heavily branched alkanes better fuel than gasoline consisting of more linear alkanes? [duplicate]

As far as I know, the reason isooctane is better than octane in gasoline engines is because the octane is more prone to ignition by pressure. This makes it ignite when it is not supposed to, which ...
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What are some convenient examples of so-called dissolved organic matter (DOM) for lab work?

Background, I have come across a chemical reaction system, occurring in nature, that apparently involves the presence of dissolved organic matter (in a catalytic role). My research returns, for ...
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Measured g-factor of a free-radical changing as a function of something. But I cant work out what?

I'm looking at EPR of a paramagnetic organic molecule in solution that has a very stable free-radical signature with gfactor ~2.0035. All good. Except when watching one particular experiment I saw ...
Tunneller's user avatar
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8 votes
1 answer
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Reaction of 1,3-dibromobutane with zinc dust upon heating

I've studied that when 1,3-dibromopropane (or in general any halogen, not just bromine) is heated with Zn dust, the electrons produced cause the halogens to break away homolytically and two free ...
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