So the ethoxide ion is almost a "bare" nucleophile. It is better able to attack the substrate and is therefore a stronger nucleophile. WARNING: Ethoxide ion is also a strong base, so you will get a competing reaction in acetone
Acetone
Acetone, or propanone, is the organic compound with the formula₂CO. It is a colorless, volatile, flammable liquid and is the simplest and smallest ketone. Acetone is miscible with water and serves as an important solvent in its own right, typically for cleaning purposes in laboratories. About 6.7 …
Is ethoxide ion a strong or weak nucleophile?
(from chemwiki.ucdavis.edu) So the ethoxide ion is almost a "bare" nucleophile. It is better able to attack the substrate and is therefore a stronger nucleophile. WARNING: Ethoxide ion is also a strong base, so you will get a competing reaction in acetone — the aldol condensation.
How does solvent affect the nucleophilicity of ethoxide ion?
The solvent affects the nucleophilicity of ethoxide ion. A polar protic solvent like methanol can participate in hydrogen bonding with a nucleophile like ethoxide ion, creating a “shell” of solvent molecules around the ion.
Why can methanol be used as a nucleophilic solvent?
A polar protic solvent like methanol can participate in hydrogen bonding with a nucleophile like ethoxide ion, creating a “shell” of solvent molecules around the ion. This decreases the nucleophilicity of the ethoxide, because the nucleophile must push these solvent molecules out of the way in order to attack the substrate.
What makes a base not a good nucleophile?
Bases will not be good nucleophiles if they are really bulky or hindered. A variety of amine bases can be bulky and non-nucleophilic. 2. Nucleophiles will not be good bases if they are highly polarizable. I- is the best example of this. Great nucleophile, really poor base. Why do we care about strong nucleophiles?
What type of solvent is involved in hydrogen bonding?
Does acetone bond to ethoxide?
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Why is ethoxide a strong nucleophile?
A polar aprotic solvent like acetone does not hydrogen bond to ethoxide ion to a significant extent. So the ethoxide ion is almost a "bare" nucleophile. It is better able to attack the substrate and is therefore a stronger nucleophile.
Is ethoxide strong or weak?
Safety. Sodium ethoxide is a strong base, and is therefore corrosive.
Is ethoxide a stronger nucleophile than hydroxide?
Ethoxide is a better nucleophile than hydroxide ion. Because of more Lewis basicity of ethoxide due to more electron density on oxygen in ethoxide (inductive +I effect of ethyl group) as compared to hydroxide ion, ethoxide is better nucleophile.
Which is the most strong nucleophile?
In acetone and other polar aprotic solvents, the trend in nucleophilicity is the same as the trend in basicity: fluoride is the strongest base and the strongest nucleophile.
How do you know if a nucleophile is strong or weak?
Nucleophilicity is measured by comparing reaction rates; the faster the reaction, the better (or, “stronger”) the nucleophile.
Why is ethoxide a strong base?
Ethoxide Ions are Strongly Basic The solution is strongly alkaline because ethoxide ions are Brønsted-Lowry bases and remove hydrogen ions from water molecules to produce hydroxide ions, which increase the pH.
Which is the weakest nucleophile?
Now, fluoride is the best nucleophile, and iodide the weakest.
Which is better nucleophile ethoxide or methoxide?
However, methoxide is only 0.82 times as nucleophilic as ethoxide (as we will show later) so the amount of methyl 12-butyl ether formed is reduced by this amount. Accordingly, the competitive reactivities of methoxide versus ethoxide in the above experiment is 4.4 times 0.82 which equals 3.6.
What is the order of nucleophilicity?
Within a group, the order of nucleophilicity is opposite to the order of basicity. This order of nucleophilicity is related to the polarizability of the nucleophile. The order I− > Br− > Cl− is one that we encounter many times in the study of reaction mechanisms. Another important relationship is RS− > RO−.
How do you rank up nucleophiles?
Within a group in the periodic table, increasing polarisation of the nucleophile as you go down a group enhances the ability to form the new C-X bond and increases the nucleophilicity, so I- > Br- > Cl- > F-.
Which one is a good nucleophile?
In general, things with extra electrons, lone pairs of electrons, and especially a negative charge, are going to be pretty good nucleophiles.
Which of the following is a good nucleophile?
Ammonia, Water, Carbanions, and Cyanide ion are a few examples of nucleophiles. To measure the nucleophilic strength, the reaction rate is calculated. The kinetically favoured reaction has a good nucleophile. A base is an electron-rich species that donates electron pairs to a hydrogen atom and forms a covalent bond.
Is ethoxide stronger than hydroxide?
Explanation: Because of the +I effect -CH2CH3 group shifts its electron density on Oxygen making it more polarizable. And thus Na ethoxide behaves stronger base than NaOH.
Is sodium ethoxide a strong base?
Sodium ethoxide is used as a strong base in organic synthesis.
Which is stronger base ethoxide or hydroxide?
The reason is also correct the ethoxide ion is the stronger base than hydroxide ion. Because of the aq. NaOH when reacts with water forms ethoxide ion but due to its basicity it abstract hydrogen reforming alcohol. hence alcohols does not reacts with the base.
Which is a weak nucleophile?
Weak nucleophiles (water, H2O and alcohols, ROH in our course) react with secondary and tertiary RX compounds (SN1 > E1 reactions). Also, methyl and primary alcohols react under strong HX acid conditions via SN2, while secondary, and tertiary alcohols react under strong HX acid conditions via SN1 (HX = HCl, HBr, HI).
What type of solvent is involved in hydrogen bonding?
A polar protic solvent like methanol can participate in hydrogen bonding with a nucleophile like ethoxide ion, creating a “shell” of solvent molecules around the ion.
Does acetone bond to ethoxide?
A polar aprotic solvent like acetone does not hydrogen bond to ethoxide ion to a significant extent.
Why is a nucleophile more nucleophilic?
This is because it can react at more sites and will not be sterically hindered if it is smaller or linear. Remember, smaller nucleophiles can fit into more places, therefore will be able to react at more places and will necessarily be more nucleophilic.
Why is nucleophilic strength relative?
This is relative because nucleophilic strength is also dependent on other factors in the reaction, such as solvent.
What happens when an atom is more electronegative?
2) Electronegativity – The more electronegative an atom is, the less nucleophilic it will be. This is because more electronegative atoms will hold electron density closer, and therefore will be less likely to let that electron density participate in a reaction. We see this in calculations and experiments that show nucleophilicity decreases as you get closer to fluorine on the periodic table (C > N > O > F)
What is the ability to distort the electron cloud of an atom?
3) Polarizability – The more polarizable an atom is, the more nucleophilic it will be. Polarizability is defined as the ability to distort the electron cloud of an atom, which allows it interact with a reaction site more easily. Generally, polarizability increases as you travel down a column of the periodic table (I > Br > Cl > F)
Is a nucleophile a good base?
Nucleophiles will not be good bases if they are highly polarizable. I- is the best example of this. Great nucleophile, really poor base.
Do nucleophiles have a negative charge?
Think about it for a second….good nucleophiles (as shown above) can have a negative charge and will almost always have a lone pair. Bases accept protons, with a negative charge or lone pair. [gasp] So it makes sense there will be at least some overlap between bases and nucleophiles.
This week's submission is from Burnie Urethra, and features a partial total synthesis of a supernatural product: Impracticatechol. Full text in comments
This week's submission is from Burnie Urethra, and features a partial total synthesis of a supernatural product: Impracticatechol. Full text in comments.
Longest known alkane?
I'm just curious, but what is the longest known alkane. The longest I've found is dictane, which has 200 carbons, but is there anything longer? And if so, what kind of purposes could it have? Thanks!
Kinda off topic,but
Some of you here probably know "The organic chemistry tutor" and how good he is.
What is a strong nucleophile?
A strong nucleophile is basically a strong base that isn't sterically hindered. This is a simplified definition, but it will almost always work.
Is it hard to draw a line when something is a strong base or a strong nucleophile?
as far as i know many compounds can act as both. there are some factors that can favor something acting as a nucleophile or as a base.
Is sodium azide a strong nucleophile?
you're welcome, glad it helped. So, sodium azide is a tricky one because it is one of the few strong nucleophiles that is a weak base (the halides also follow this rule). It is a strong nucleophile because it has that negative charge. I'm not entirely sure why it is a weak base, but I believe it is because the molecule is stabilized due to resonance. So, if it is a strong nucleophile, it will favor SN2, which needs a good nucleophile. It does not favor E2 because E2 needs a strong base that will donate to the hydrogen. Think of it as you would with a halide. You know that halides are strong nucleophiles and they occur frequently in substitution reactions, but you would never use a halide for an elimination reaction because it is a weak base.
What type of solvent is involved in hydrogen bonding?
A polar protic solvent like methanol can participate in hydrogen bonding with a nucleophile like ethoxide ion, creating a “shell” of solvent molecules around the ion.
Does acetone bond to ethoxide?
A polar aprotic solvent like acetone does not hydrogen bond to ethoxide ion to a significant extent.