The phenolate ion can react with carbon dioxide to form carboxylic acids. This reaction is one of the steps in the synthesis of acetylsalicylic acid (aspirin). The reaction, which is carried out under 100 atm. pressure of carbon dioxide, is called the Kolbe reaction. It is named after the German chemist H.

What is Kolbe reaction in chemistry?

1 : the synthesis of a hydrocarbon (as ethane) by the electrolysis of a salt (as sodium acetate) 2 : the synthesis of salicylic acid by heating a mixture of sodium phenoxide and carbon dioxide under pressure at 180° to 200° C.

What is a Phenolate?

Phenolate is a phenolate anion that is the conjugate base of phenol obtained by deprotonation of the OH group. It has a role as a human xenobiotic metabolite. It is a conjugate base of a phenol. ChEBI.

Is Phenolate a strong Nucleophile?

Phenols are in fact potent nucleophiles, but their electron density is NOT localized to the oxygen centre.

Is Phenolate ion aromatic?

Phenols certainly behave like benzene and are therefore aromatic, please note that aromaticity is an experimentally observed feature. You can see the aromaticity from the π type orbitals, that are in both cases quite similar and extensively delocalised.

A Level Chemistry Reactions of Phenol

38 related questions found

Is Phenolate a strong base?

However, phenol is sufficiently acidic for it to have recognizably acidic properties - even if it is still a very weak acid. A hydrogen ion can break away from the -OH group and transfer to a base. For example, in solution in water: Phenol is a very weak acid and the position of equilibrium lies well to the left.

What is resonance in benzene?

Resonance in benzene: Benzene ring has three double bonds in it and is expected to be quite reactive. ... Due to resonance in benzene, the carbon-carbon bonds in benzene acquire an intermediate character of carbon-carbon single and double bonds.

Which is better nucleophile PhO or AcO?

AcO- is conjugate base of acetic acid. So, it is not a very good nucleophile. In PhO-, the negative charge is in resonance with the ring. So, the effective of negative charge further decreases.

What is MBD and nucleophile?

An ambident nucleophile is an anionic nucleophile whose negative charge is delocalized by resonance over two unlike atoms or over two like but non-equivalent atoms. The most common ambident nucleophiles are enolate ions. For example, the resonance forms of acetone enolate are shown below.

Why is aniline a good nucleophile?

Is aniline a good nucleophile? ... Aniline is not a good nucleophile because the lone pair of electrons of nitrogen are resonance stabilized by the benzene ring. Anilinium chloride is also not a good nucleophile, and actually acts as an electrophile. So rather than donating electrons, it accepts.

Is Phenolate an acid?

For example, in solution in water: Phenol is a very weak acid and the position of equilibrium lies well to the left. Phenol can lose a hydrogen ion because the phenoxide ion formed is stabilised to some extent. The negative charge on the oxygen atom is delocalised around the ring.

What is carbolic acid used for?

Carbolic acid is used to make plastics, nylon, epoxy, medicines, and to kill germs. Also called phenol.

Is carbolic acid harmful?

Damage continues to occur to the esophagus and stomach for several weeks after the poison was swallowed. Death may occur as long as a month later.

What is Kolbe reaction with example?

(i) Kolbe's reaction: When phenol is treated with sodium hydroxide, sodium phenoxide is produced. This sodium phenoxide when treated with carbon dioxide, followed by acidification, undergoes electrophilic substitution to give ortho-hydroxybenzoic acid as the main product. This reaction is known as Kolbe's reaction.

What reagent is Kolbe reaction?

Applications of Kolbe Reaction

When Potassium Hydroxide is used in the Kolbe reaction, 4-Hydroxybenzoic acid can be accessed. This is an important precursor for parabens (parahydroxybenzoate or ester of para-hydroxy benzoic acid, used as a biocide in cosmetic products).

What is Sulphonation of phenol?

sulphuric acid is known as the sulphonation of phenol. The product of sulfonation depends upon the temperature. ... At high temperature, it's not possible to form any interaction and hence steric repulsion overcomes the attraction. Para-phenol sulfonic acid is obtained at high temperature.

What are nucleophiles with examples?

Examples of nucleophiles are the halogen anions (I^-, Cl^-, Br^-), the hydroxide ion (OH^-), the cyanide ion (CN^-), ammonia (NH₃), and water. Compare electrophile.

What is nucleophile give example?

Types. Examples of nucleophiles are anions such as Cl⁻, or a compound with a lone pair of electrons such as NH₃ (ammonia), PR₃. In the example below, the oxygen of the hydroxide ion donates an electron pair to form a new chemical bond with the carbon at the end of the bromopropane molecule.

What are MBD and nucleophiles explain with an example?

Ambident nucleophiles are nucleophiles having two nucleophilic sites. Thus, ambident nucleophiles have two sites through which they can attack. For example, nitrite ion is an ambident nucleophile. Nitrite ion can attack through oxygen resulting in the formation of alkyl nitrites.

Which is more stable PhO or PhS?

There are plenty of cases of more 'stable' anions that are more nucleophilic than less 'stable' ones. I mentioned sulphur derivatives. PhSH is about 2000 times more acidic in water than PhOH, but PhS^- is more nucleophilic than PhO^-.

What is the order of nucleophilicity?

Across a row in the periodic table nucleophilicity (lone pair donation) C^- > N^- > O^- > F^- since increasing electronegativity decreases the lone pair availability. This is the same order as for basicity.

What is PhO organic chemistry?

In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C₆H₅. Phenyl groups are closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group.

What is resonance explain in short?

1. Resonance is the ability of system to move its pi electrons in the system. 2. The delocalized electron when show movement contributing structures are prepared , this structures are called as resonating structures. Example : Benzene shows resonance.

What is resonance and resonance effect?

Resonance effect is the polarity produced in a molecule due to interaction between a lone pair of electron and a pi bond or it is produced due to interaction of two pi bonds between two adjacent atoms.

What is the simple definition of resonance?

In physics, resonance is the tendency of a system to vibrate with increasing amplitudes at some frequencies of excitation. These are known as the system's resonant frequencies (or resonance frequencies). The resonator may have a fundamental frequency and any number of harmonics.