Questions tagged [organic-chemistry]
Use this tag for questions relating to organic molecules and their properties (structure of organic molecules, spectroscopic properties, reaction mechanisms, stereochemistry etc). DO NOT use this tag as the only tag in your question, as this tag by itself cannot appropriately classify your question. Always use this tag in addition to other more specific tags.
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What is the size parameter of the direct red 80 molecule?
Basic information:
CAS number: 2610-10-08
Molecular formula: C45H26N10Na6O21S6
Molecular weight: 1373.07
Structural formula:
For example:
For congo red whose structural formula is demonstrated below, ...
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Does nitroprusside test only work for ketones and not aldehydes?
Since the Brady test will be positive for both aldehydes and ketones, we need a way to distinguish between the two. The Tollen's test is only positive for aldehydes (and $\alpha$-hydroxyketones). I ...
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Why O-H bond and not C-O bond breaks in Acid Catalyzed Hydration of Alkene?
Recently, while studying Hydrocarbons I came across this reaction (Acid catalyzed hydration of an alkene)
What I don't get here is that the breaking of O-H bond (in Step 3) and not the C-O bond, even ...
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Why is fermentation of cellulose to produce biofuel and nutrients so difficult?
The formula for glucose is $\ce{C6H12O6}$ and that of cellulose is very similar $\ce{C6H10O5}$. Glucose can be readily fermented by yeast and other micro-organisms to produce carbon dioxide and ...
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Bonding and antibinding orbital energy difference
Reading Claydens organic chemistry, in chapter 5 it states that Br-Br makes a good electrophile while the C-C in ethane doesnt because the energy difference between bromines bonding and anti bonding ...
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Cation/Anion UV-Vis absorption
I want to understand how the ground state absorption of a molecule shifts if an electron is added or removed. I found these two publications 1 and 2 that observe shifts, but both times a redshift, be ...
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ppm as hexane/propane/methane etc
This question is primarily related to stack testing data.
Whenever stack testing is being conducted and the parameter being measured is VOC concentration, it is often reported as ppm (as hexane) or ...
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How is nitrogen the most powerful electron donor in aromatic rings?
In Clayden, page 735, Aromatic Heterocycles 1:Reactions:
The other simple five-membered heterocycles are furan, with an oxygen atom instead of nitrogen, and thiophene, with a sulfur atom. They also ...
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Hydrolyse a fluorophosphonic compound / Which protective group strategy can I use for phosphonate esters to access the free acid after a reaction?
I have a synthetic problem in my PhD thesis, in which I synthesize a phosphonate ester.
To be more precise, it is a phosphonofluoridic compound. In my specific case, the fluorine attached to the ...
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What is has a higher priority in naming organic compounds, alkyl groups or halides?
2-Chloro-3,3-dimethylbutane or 3-Chloro-2,2-dimethylbutane?
According to these sources, both are correct:
NIST/TRC Web Thermo Tables (WTT)
ChemSpider
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How to name an ester with an alkene or alkyne as the R group? [closed]
More specifically, see the image down below:
Would it be pentan-2-ene-3-yl propanoate? Do you just add the 2-ene to specify the position of the double bond?
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What is the number of different compounds formed from the monochlorination of cis-1,2-dimethyl cyclopentane?
I encountered this question in the Black Book of Organic Chemistry by Ashish Mishra while preparing for a college entrance exam.
According to the answer key the answer is 12. I have only managed to ...
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Why does polar solvents favor Ketonization and non-polar solvents favor Enolization? [duplicate]
I was just studying isomerism, when I came across this statement for keto-enol tautomerism:
A polar solvent favors ketonization, while a non-polar solvent favors enolization.
And I just can't get my ...
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Mesomeric form and organic reaction [closed]
I'm looking to find all the mesomeric form of the compound A. I don't know how to take it because there is triple bond. I think one bond of the double bond of ceton can go on the oxygen, but after ...
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Isoelectric Point
How do we derive the formula of isoelectric point?
pI=(pKa1 + pKa2)/2
I read that isoelectric point is defined as the pH at which degree of protonation in amino group is same as degree of ...
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Stereoselectivity of the homogeneous catalytic hydrogenation of 2-Methylenebicyclo[2.2.1]heptane using wilkinson's catalyst
For the following reaction, 2 products are available: in one, the methyl group is axial, and in the other, it is equatorial.
The addition of hydrogen to the double bond is a syn addition to the less ...
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Neighbouring Group Participation of Aldehyde group
Does the aldehyde group -CHO give neighbouring group participation? For example in the following compound:
Why or why not will the formyl group show neighboring group participation? Although I have ...
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What is the pKa of methylamine
I completed a practice (not for marks) assignment for an organic chemistry course, and one of the questions asked for the pKa of methylamine.
I looked on PubChem, and it gave a result of $10.6$. ...
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How to remove hexane from nBuLi
As described in a paper, the authors removed the hexane from the nBuLi solution "under reduced pressure".
I was wondering if anyone had any experience on how to proceed safely with this ...
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Why isn't the dielectric constant for molecules like methanol higher than water using inductive effect?
The dielectric constant of a more polar molecule should be higher than a molecule which is less polar(polarity can be measured by dipole moment), so methanol should have higher dipole moment than ...
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Why is the ketone not attacked by the Grignard reagent/cuprate in this case but a double bond is?
According to the book the answer is (a)
Here I assume transmetallation occurs and then the nucleophilic carbon of methyl attacks the ring but what I don’t understand is why the ketone remains ...
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Ratio of amounts of different mono substituted alkanes (by halogenation)
My problem here is the I'm unable to use the information for reactivity of C-H bonds to calculate the amount of mono chlorides. If anyone can help me in the process, that would be great.
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Should I add more of a trihydrate chemical to a solution if recipe calls for hemihydrate?
I am running phosphate by the ascorbic acid method (SM 4500-PE, PDF), and making the antimony potassium tartrate reagent. Standard methods uses $\pu{1.3715 g}$ of $\ce{K(SbO)C4H4O6 * 1/2 H2O}$ per $\...
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What is the priority of an alkyl substituent containing double or triple bonds, in comparison to the other functional groups?
If we have an alkyl substituent containing a double bond(s) or triple bonds(s), what is it's priority in comparison to other functional groups and substituents?
For example, take the compound given ...
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Major product in chloro-sulfonation of toluene
According to Clayden's Organic Chemistry (2e) (p.485)
... and the acid chloride (tosyl chloride, $\ce{TsCl}$) needed to make tosylates can be made from the acid in the usual way (p. 215) with $\ce{...
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Why is +M effect of OH greater than OR?
In some books it is written that +M (mesomeric effect) effect of OH is less than that of OR. The reason they give is inductive effect of R (group) which sounds plausible. But in some places it is ...
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Ambimodal transition states in some organic reaction pathways
In many computational studies, mechanisms appear to have so-called ambimodal transition states, i.e. a transition state which can lead to multiple products, in conflict to the common undergraduate ...
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Why is cyclooctene the smallest cycloalkene to have cis-trans isomerism?
What prevents cis and trans isomers from existing in smaller cycloalkenes, for example, cyclohexenes for more than a short period of time?
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Why is benzoic acid a stronger acid than 3-aminobenzoic acid?
Why is benzoic acid a stronger acid than 3-aminobenzoic acid? Obviously at meta position, only negative inductive effect will operate. But, how does that make it a weaker acid than benzoic acid?
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The Role of Acidified Potassium Manganate(VII) in Oxidation of Alcohols [closed]
The chemical equation for the oxidation of ethanol is given as:
$$\ce{C2H5OH + 2[O] -> CH3COOH + H2O}.$$
Acidified potassium manganate (VII) solution $\ce{KMnO4}$ is added as the oxidising agent. ...
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History of Azeotrope (azeotropic mixtures)
I'm currently researching the history of azeotropic mixtures for an essay, and I've come across some interesting information. The term "azeotrope" was coined in 1911 by English chemists John ...
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Extended resonance and colour [duplicate]
I was pretty sure that this would've been asked before but I couldn't find anything here. I've noticed that system with multiple benzene rings and pi donating/accepting groups tend to be quite ...
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Simplest way to convert glucose into water and carbon dioxide other than burning?
What is the simplest pathway from glucose to $\ce{H2O}$ and $\ce{CO2}$, such that
all reactions happen in aqueous solution with pH between 5 and 8,
temperature is in range between 0 and 35 °C,
no (...
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Definition of alpha-carbon [duplicate]
What is an $\alpha$-carbon, and how can I identify one?
The other questions because of which my questions has been termed as duplicated is asking about alpha carbons in alkyl halide , while my ...
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How is the alpha carbon defined in alkyl halides?
The α carbon refers to the first carbon that attaches to a functional group. According to this information, the alpha carbon in 2-bromobutane should have been the carbon next to the one with ...
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Ambiguous nature of aldehydic group in glucose
In aqueous solution, α-anomer and β-anomer of glucose
remain in equilibrium with each other along with a small amount of
glucose in open chain form ($0.02~\%$). The open chain form in ...
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Acidic strength of 4-(tribromomethyl) benzoic acid vs 4-(trichloromethyl) benzoic acid
From what I leart from my teacher is that 4-(tribromomethyl) benzoic acid is more acidic than 4-(trichloromethyl) benzoic acid. But I'm not sure what the reason is.According to me 4-(trichloromethyl) ...
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Order of positive mesomeric effect of halides
I learned that the order of $+M$ effect (mesomeric effect) for halogens is as follows: $\ce{F} > \ce{Cl} > \ce{Br} > \ce I$.
I wonder why this is so?
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ortho-bromoanisole + NaNH2 + Liquid NH3 =?
when we add ortho-bromoanisole in NaNH2 + NH3 we form products using the benzyne mechanism.
here, we form the products considering only -I effect of -OCH3, if we consider its +M effect we would form, ...
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Why does acidity increase going from sulfide to sulfoxide to sulfone?
It is fairly well-known that the acidity of a proton alpha to a sulfide/sulfoxide/sulfone increases in that order. Some pKa values (in DMSO), courtesy of the Evans pKa table:
Traditionally this has ...
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Why does a mixture of nitrous acid with concentrated nitric acid cause nitration of benzene instead of nitrosation?
A question came up in our worksheet to predict the reaction product of nitrous acid and concentrated nitric acid with benzene.
I quickly recognized it to be similar to the nitration reaction. ...
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Storing 'Tollens Reagent'?
I have read that tollens reagent is unstable and hence must be freshly prepared before testing. However my school has a bottle of 'tollens reagent' on the shelf for use in organic qualitative analysis ...
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What is the correct reaction mechanism for the following :
The question is :
Now, this is what I have done :
So I dont know how to proceed to the final product. In some book they tell we need to break the cyclopropane to get the desirable answer but how ?
...
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Inductive Effect (R-NH3+ and R-NH2)
Textbooks I've read state that R-NH3+ has exhibits a greater -I inductive effect than R-NH2 does.
However, I've also read in places that the + charge in R-NH3+ only represents a formal charge and has ...
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Why is formyl chloride unstable while higher acyl chlorides are stable?
From Bruice's Organic Chemistry, section 18.6 Friedel–Crafts acylation of benzene [1, pp. 876–877]:
Friedel–Crafts acylation places an acyl group on a benzene ring, and Friedel–Crafts alkylation ...
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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 ...
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What can I do if a peptide won't go in solution in a biological assay?
I have working on the realisation of on assay, that is intended to examine the activity of a protein. The assay works in a way, in which the product of the target enzyme is transfered by a support ...
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Does the magnesium 2+ ion prefer tetrahedral or octahedral coordination?
In organic chemistry I was told that the magnesium ion which is part of Grignard reagents is coordinated to several ether molecules. The overall structure around the magnesium is tetrahedral, which ...
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Why hyperconjugation is called as σ to π* donation for alkenes and alkynes?
Why hyperconjugation is called as σ to π* donation for alkenes and alkynes if for C2 lowest unoccupied molecular orbital is σ2p not π*2p?
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Determining R-S configuration with lowest priority groups in plane of paper
I was studying R-S nomenclatures and determining configurations of molecules when I came across a certain problem, which had the 4th priority group on the plan of paper (not on a dash or wedge)
...
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