Questions tagged [esters]

For questions about the synthesis, properties, and reactions of ester compounds, both organic and inorganic.

Filter by
Sorted by
Tagged with
3
votes
1answer
1k views

Ethyl Acetate: how to store

I'm a 3D printing hobbyist and a few months ago I bought some Ethyl Acetate after learning online that it might have a similar effect on PLA as acetone has on ABS. From the tests I made, I was either ...
5
votes
1answer
13k views

Sulphuric Acid in Esterification Reaction

Why is it that adding the sulphuric acid slowly to a solution of alcohol and carboxylic acid (making an ester) will increase the yield of the product? It seems that not only does the rate at which it ...
1
vote
0answers
971 views

Esterification Colour Change

I was in a chemistry lecture about the upcoming laboratory practical on esters that I would have to take. My lecturer had mentioned that we ought not worry about "the pink coloration that will occur" ...
4
votes
1answer
397 views

Hydrolysis of an ester

An organic compound X of formula $\ce{C5H10O2}$ forms two compounds when boiled in aqueous sodium hydroxide solution. One of these compounds forms a ketone when treated with acidified potassium ...
9
votes
2answers
1k views

Why are peroxides unstable but disulfide bridges considered stable? Why are esters stable but thiolesters are unstable?

I can not understand why a peroxide $\ce{R-O-O-R}$ is considered reactive and unstable. Going down one row on the periodic table, a disulfide bridge ($\ce{R-S-S-R}$) is apparently super stable and ...
3
votes
0answers
648 views

Purification of polar NHS esters

What are the options that I might be missing for the purification of a molecule with the following characteristic: Contains an activated ester that reacts with water (NHS) Reacts readily with ...
0
votes
2answers
1k views

Esterification with tertiary alcohol

I saw a different mechanism for esterification of tertiary alcohol in a book. They say that first the $\ce{OH}$ is protonated and it leaves to form the tertiary carbocation. Then the oxygen's lone ...
1
vote
0answers
724 views

Saponification value of a fat/oil

The saponification value of a fat was determined by adding $\pu{9.0 g}$ of the fat to flask containing $\pu{50.0 cm3}$ of $\pu{1.00 M}$ ethanolic potassium hydroxide. The remaining solution was ...
5
votes
1answer
3k views

Protonation of Carbonyl oxygen in Fischer Esterification

In the Fischer Esterification, why is it the acid's carbonyl oxygen getting protonated and not the hydroxyl oxygen? This protonation occurs in Step 1 of the mechanism below. I read in some textbooks ...
0
votes
2answers
2k views

selective hydrolysis problem

I am aware that esters can be selectively hydrolysed depending on the type of alkyl group present e.g. Me ester vs t-butyl ester, the latter is reactive to acidic conditions and not basic because of ...
1
vote
0answers
595 views

Are esters and amides soluble in cold acids/bases? [closed]

The main problem I have is that we say amines are soluble in acids because they are bases, and they will thus react with acids. But if A reacts with B, how does that imply A is soluble in B? Yes, ...
1
vote
1answer
8k views

Is the reaction between a carboxylic acid and alcohol endothermic?

I would say that it is endothermic, and then by increasing the temperature, one could get more product, disturbing the equilibrium. Is this true, though? During an esterification, some bonds are ...
2
votes
0answers
274 views

Hoffmann's rule in ester pyrolysis

Why is the Hoffmann's product the major product in the pyrolysis of an ester to form a carboxylic acid and alkene?
4
votes
2answers
1k views

Which side of the C-O-C bond breaks in esters during hydrolysis in basic medium?

When an ester undergoes hydrolysis which side of the $\ce{C-O-C}$ breaks for instance in the following example: I believe the first is correct but is it a rule that the salt of a carboxylic acid is ...
2
votes
1answer
1k views

Why do esters have to be distilled during purification?

I am currently designing a lab experiment for a school project in which I am to determine the effect of catalyst concentration ($\ce{H2SO4}$) on the rate of reaction between methanoic (formic) acid ...
1
vote
1answer
1k views

Direct conversion of amides to esters

Rarely does the literature describe the synthesis of esters from amides. I understand that amides are a relatively unreactive functional group but they can easily be hydrolysed to give carboxylic ...
7
votes
2answers
601 views

Retrosynthesis of a lactone

We have been asked to do a retrosynthesis of (6⁠S)-6-[(2⁠S)-2-hydroxy-4-phenylbutyl]oxan-2-one J from 3-phenylpropan-1-ol K: My first instinct would be to do a functional group interconversion of the ...
6
votes
1answer
2k views

Finding the mystery ester strucuture using NMR

I have an unknown ester with the chemical formula $\ce{C9H10O2}$ that is used as a flavoring agent in candies. It exhibits the following H-NMR and C-NMR (Attached file: unknown ester NMR) Based on ...
2
votes
0answers
3k views

Will oxalic acid react with ethanol?

Will oxalic acid, in a saturated solution in ethanol, be able to undergo an esterification reaction with the ethanol? This is assuming no acidifying agents (or anything else, for that matter) are ...
1
vote
1answer
249 views

Why is the ester bond stable under Reformatsky reaction conditions?

The following reaction is a Reformatsky reaction. Why is the ester bond not attacked in the last step? Couldn’t $\ce{OR3}$ be replaced by $\ce{OH}$ or $\ce{O(molecule)}$?
4
votes
1answer
464 views

Naming of ester alkoxide

I'm trying to name the following compound: I believe the carboxyl group has priority and should make up the parent name. I'm not sure how to name the alcohol derivative portion. My first thought is: ...
1
vote
1answer
215 views

What is the major hydrolysis product of 2,2,2-trifluoroethyl 2-acetamido-3-phenylprop-2-enoate?

In the below reaction we have to find the major hydrolysis product of 2,2,2-trifluoroethyl 2-acetamido-3-phenylprop-2-enoate. My doubt is why the major hydrolysis is not when $\ce{OH-}$ at the $\ce{C}...
2
votes
1answer
5k views

Will glycerol and citric acid react? If yes, under what conditions?

I would like to know whether the reaction will take place if glycerol and citric acid are merged? In particular, what will happen if both substances are heated up to high temperature (+100°C)?
11
votes
1answer
256 views

Which electronic effects are responsible for the reduction of nucleophilicity of a hydroxy group orthogonal to an ester?

I am facing a similar synthetic problem as Boekman Jr. et al noted in their synthesis of Tetronolide.[1] I will quote their’s rather than disclosing my actual synthetic problem, but note that the key ...
0
votes
1answer
975 views

What determines the boiling point of esters of the same number of carbon atoms but different structural formula?

The boiling point of esters increases with molecular weight (and therefore, number of carbon atoms) because of more dispersion forces. But if you had two different esters with the same number of ...
6
votes
2answers
720 views

How is the configuration of an ester enolate double bond assigned according to CIP?

Two principal modern methods for enantioselective aldol reactions — the Evans aldol and the Masamune aldol — use a carboxylic-acid derived enolate rather than a ketone enolate as e.g. in the Paterson ...
5
votes
1answer
542 views

Is Nitroglycerine a Nitro Compound or an Ester?

I looked up nitroglycerine in a science dictionary (Oxford Dictionary of Science, 2003), and it explicitly mentions that nitroglycerine is an ester and not a nitro compound. However my teacher told ...
7
votes
1answer
507 views

What is the name of this ester?

Can you tell me the name of this ester? It is two $\ce{C8}$ fatty acids ester-linked with a molecule of 1,3-butanediol in the middle. I would be tempted to say (R)-butanediol-1,3-diyl dihexanoate, but ...
1
vote
0answers
100 views

Organic polyether with carboxyl moiety reacting with aldehyde, following reaction with sulfuric acid

I want to react the following molecule with conc. sulfuric acid in the presence of methanol at room temperature: If I am right, this would make a methyl ester to be formed on the carboxyl. The aim ...
0
votes
2answers
251 views

Formation of Lactone from 5-amino-decanoic acid?

As expressed in the title, I am trying to figure out how to form a lactone from 5-amino-decanoic acid. The thing that comes to my mind as a start is the attachment of the amino group ($\ce{NH2}$) to ...
1
vote
1answer
2k views

In a condensation reaction, which of the reactants loses their OH group?

You have Propanoic Acid ($\ce{CH3CH2CO-O-H}$) so an $\ce{OH}$ on the end You have Ethanol ($\ce{CH3CH2-OH}$) so an $\ce{OH}$ on the end When you combine the two for a condensation reaction you have ...
0
votes
2answers
970 views

Will sulphuric acid react with water produced in an esterification process?

Sulphuric acid acts as a catalyst to catalyze the reactions of alcohol and carboxylic acid to form ester. Alcohol reacts with carboxylic acid to produce ester and water. However, as sulphuric acid ...
0
votes
3answers
588 views

What techniques can determine the concentration of ethyl acetate in a solution containing ethyl acetate, acetic acid, ethanol and water?

I need to monitor the concentration of ethyl acetate in an Fischer esterification reaction. What techniques or spectroscopies can detect the concentration of the compound? And which one do you ...
3
votes
1answer
3k views

Failed esterification of 1-butanol and ethanoic acid

I did an esterification experiment of 1-butanol and ethanoic acid. 30 mL of 1-butanol was added followed by 30 mL of ethanoic acid, and then 1.5 mL of concentrated sulphuric acid and some boiling ...
1
vote
2answers
5k views

Differentiating esters from glycosidic linkages

What exactly is the difference between an ester linkage and a glycosidic linkage? I know both release a molecule of water, but what is the difference? Is it simply which types of monomers are involved ...
2
votes
1answer
174 views

Why are the ethyl ester methylene protons not diastereotopic in ethyl (+-)-2-methylbutyrate?

In the following compound, there is one chiral center and two methylene groups. Why are the protons on the ethyl ester methylene not diastereotopic?
1
vote
0answers
250 views

Why does adding PBS to a lipid+propylene glycol solution cause the lipid to precipitate?

I am trying to create an aqueous phospholipid suspension using ~50 mg of 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC), 13 mL of propylene glycol (PG), and 72 mL of phosphate-buffered saline (PBS)....
3
votes
1answer
745 views

Why aqueous hydroxide is slippery (beyond just saponification)

A recent question mentions: Bases are soapy to touch because of soap formation on contact with lipids present on our skin. This is always the reasoning I hear, as well, and searching the internet ...
5
votes
1answer
665 views

Does the Dieckmann Reaction proceed via the conjugated enolate of the product?

In the following mechanism of the Dieckmann Condensation, the product has been formed in the fourth step, but still the reaction proceeds and $ \ce{RO^{-}}$deprotonates the product. Then $\ce{H^{+}}$ ...
1
vote
1answer
306 views

Naming of bicyclo[2.2.1]hept-5-ene-1,4,5,6-tetramethyl-3-bromo-2-ethyl carboxylate

I've synthesized a molecule (depicted above) using a Diels-Alder reaction, and I can't find it in any database (I used scifinder for my search), so I need advice about the name. The name I came up ...
0
votes
1answer
543 views

which starting material on heating with concentrated sulfuric acid generate cyclic ester

I have just learned esterification of normal reactions with aliphatic compounds, but this one is a cyclic compound. Is it different? There are both a hydroxyl group and a carboxyl group in choice B ...
1
vote
1answer
2k views

Alkaline Ester Hydrolysis Reaction

In an ester hydrolysis reaction using a dilute base what is the pH change before and after the reaction occurs. In this reaction I want to react methyl ethanoate with dilute sodium hydroxide. I want ...
1
vote
1answer
1k views

How can the formation of an alkene be explained during the hydrolysis of an ester when the alkoxy moiety is tertiary?

$$ \ce{RCOOR' + H2O -> RCOOH + R'OH} $$ But when $\ce{R'}=3^\circ$ it may result in the formation of alkene. But by the normal mechanism given in books and in various sites I am not able to explain ...
4
votes
2answers
151 views

How does this brominated intermediate lose its methyl group?

The problem is such: So far my working has been: I'm concerned about the last step where the ester forms a ring. The methyl group doesn't look like a plausible leaving group, but it does not ...
4
votes
1answer
152 views

Why does a carbonyl reform in ester reactions

I have noticed that frequently whenever esters react with a nucleophile, the nucleophile will attack the carbonyl carbon and eventually in order for the carbonyl to reform the other oxygen will leave ...
7
votes
2answers
915 views

Choice of base for malonic ester synthesis

Most reaction mechanisms use $\ce{EtO-}$ as a base to deprotonate the alpha hydrogen in the malonic ester sythesis. But in the equilibrium there are still esters that haven't been deprotonated. Why ...
5
votes
2answers
858 views

How to esterify phenol with oxalic acid?

Is it possible to fully esterify phenol with oxalic acid in order to get diphenyl oxalate? What catalyst should I use and is the synthesis possible to perform at home with hobby equipment?
2
votes
1answer
715 views

Mechanism for oxidative cleavage of tertiary alcohols by NaOCl

I came across this today An ester $\ce{C4H8O2}$ on reaction with $\ce{CH3MgCl} $ and hydrolysis gives an alcohol. The alcohol on reaction with $\ce{NaOCl}$ and $\ce{H3O+}$ gives acetic acid. ...
2
votes
2answers
3k views

Routes of formation of esters with highest yield

Esters can be formed in two ways according to the syllabus I'm following: (1) Mixing an alcohol with a carboxylic acid in the presence of sulfuric acid; and (2) Mixing an alcohol with an acid ...
8
votes
1answer
276 views

How can rotamers of alpha-keto esters be named to distinguish between different geometries?

When talking about free rotation it is often helpful to determine about which geometric arrangement one is referring to. For example in the case of butane we talk about several eclipsed or staggered ...