Kolbe–Schmitt reaction: Difference between revisions

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{{Short description|A chemical reaction used in organic chemistry}}
{{Short description|A chemical reaction used to synthesize salicylic acid}}
{{Use dmy dates|date=October 2023}}


The '''Kolbe–Schmitt reaction''' is an important [[chemical reaction]] in [[organic chemistry]] that involves the carboxylation of [[phenolates]] to produce [[salicylic acid]] derivatives. This reaction is named after the chemists [[Hermann Kolbe]] and [[Rudolf Schmitt]], who developed the process in the late 19th century.
== Kolbe–Schmitt reaction ==
The '''Kolbe–Schmitt reaction''' is an important [[chemical reaction]] in organic chemistry that involves the [[carboxylation]] of [[phenolates]] to produce [[salicylic acid]] derivatives. This reaction is named after the chemists [[Hermann Kolbe]] and [[Rudolf Schmitt]], who developed the process in the late 19th century.


==Mechanism==
[[File:Kolbe-Schmitt-reaction-mechanism.png|thumb|right|300px|Mechanism of the Kolbe–Schmitt reaction]]
The Kolbe–Schmitt reaction proceeds through the reaction of a [[sodium phenoxide]] with [[carbon dioxide]] under high pressure and temperature conditions. The general mechanism involves the following steps:


# '''Formation of Sodium Phenoxide''': [[Phenol]] is treated with [[sodium hydroxide]] to form sodium phenoxide.
== Mechanism ==
# '''Carboxylation''': The sodium phenoxide is then exposed to carbon dioxide gas at elevated temperatures (around 125–150 °C) and pressures (approximately 100 atm). This results in the formation of an [[ortho-carboxylate]] intermediate.
The Kolbe–Schmitt reaction proceeds through the following steps:
# '''Acidification''': The reaction mixture is acidified, typically with [[sulfuric acid]], to yield the desired [[salicylic acid]].


[[File:Kolbe-Schmitt reaction mechanism.png|thumb|right|300px|Mechanism of the Kolbe–Schmitt reaction.]]
# '''Formation of the phenolate ion''': The reaction begins with the deprotonation of a [[phenol]] to form a [[phenolate ion]]. This is typically achieved by treating the phenol with a strong [[base]] such as [[sodium hydroxide]] (NaOH).
# '''Carboxylation''': The phenolate ion is then reacted with [[carbon dioxide]] (CO₂) under high pressure and elevated temperature. This step results in the formation of a [[carboxylate]] intermediate.
# '''Protonation''': The carboxylate intermediate is then protonated to yield the final product, which is a [[salicylic acid]] derivative.


==Applications==
The overall reaction can be summarized as follows:
The primary application of the Kolbe–Schmitt reaction is in the industrial production of [[salicylic acid]], which is a precursor to [[aspirin]] and other pharmaceuticals. Salicylic acid is also used in the manufacture of dyes, preservatives, and as a [[keratolytic]] agent in dermatology.


==Advantages and Limitations==
: C₆H₅ONa + CO₂ + H₂O → C₆H₄(OH)COOH + NaOH
The Kolbe–Schmitt reaction is advantageous due to its ability to selectively carboxylate phenolates at the ortho position. However, the reaction requires harsh conditions, including high temperatures and pressures, which can limit its applicability in some contexts. Additionally, the reaction is specific to phenolates and does not work well with other types of [[aromatic compounds]].


==Historical Context==
== Applications ==
The development of the Kolbe–Schmitt reaction marked a significant advancement in the field of organic synthesis. Hermann Kolbe first discovered the reaction in 1860, and it was later refined by Rudolf Schmitt in 1885. This reaction laid the groundwork for the synthesis of many important [[aromatic carboxylic acids]].
The Kolbe–Schmitt reaction is primarily used in the industrial production of [[salicylic acid]], which is a precursor to [[aspirin]] and other pharmaceuticals. Salicylic acid is also used in the manufacture of dyes, preservatives, and as a [[keratolytic]] agent in dermatology.


==Related pages==
== Historical significance ==
The development of the Kolbe–Schmitt reaction marked a significant advancement in the field of organic synthesis. It provided a practical method for the large-scale production of salicylic acid, which was previously difficult to synthesize efficiently. This reaction laid the groundwork for the development of [[non-steroidal anti-inflammatory drugs]] (NSAIDs) and other important medicinal compounds.
 
[[File:K_S_startAnimGif.gif|thumb|left|300px|Animation of the Kolbe–Schmitt reaction]]
 
== Related pages ==
* [[Salicylic acid]]
* [[Salicylic acid]]
* [[Aspirin]]
* [[Aspirin]]
* [[Carboxylation]]
* [[Carboxylation]]
* [[Phenol]]
* [[Phenol]]
* [[Organic chemistry]]
* [[Hermann Kolbe]]
* [[Rudolf Schmitt]]


[[Category:Organic reactions]]
[[Category:Organic reactions]]
[[Category:Carbon dioxide]]
[[Category:Carbon-carbon bond forming reactions]]
[[Category:Carboxylation reactions]]
[[Category:Name reactions]]

Latest revision as of 14:13, 21 February 2025

A chemical reaction used to synthesize salicylic acid


Kolbe–Schmitt reaction[edit]

The Kolbe–Schmitt reaction is an important chemical reaction in organic chemistry that involves the carboxylation of phenolates to produce salicylic acid derivatives. This reaction is named after the chemists Hermann Kolbe and Rudolf Schmitt, who developed the process in the late 19th century.

Mechanism of the Kolbe–Schmitt reaction

Mechanism[edit]

The Kolbe–Schmitt reaction proceeds through the following steps:

  1. Formation of the phenolate ion: The reaction begins with the deprotonation of a phenol to form a phenolate ion. This is typically achieved by treating the phenol with a strong base such as sodium hydroxide (NaOH).
  2. Carboxylation: The phenolate ion is then reacted with carbon dioxide (CO₂) under high pressure and elevated temperature. This step results in the formation of a carboxylate intermediate.
  3. Protonation: The carboxylate intermediate is then protonated to yield the final product, which is a salicylic acid derivative.

The overall reaction can be summarized as follows:

C₆H₅ONa + CO₂ + H₂O → C₆H₄(OH)COOH + NaOH

Applications[edit]

The Kolbe–Schmitt reaction is primarily used in the industrial production of salicylic acid, which is a precursor to aspirin and other pharmaceuticals. Salicylic acid is also used in the manufacture of dyes, preservatives, and as a keratolytic agent in dermatology.

Historical significance[edit]

The development of the Kolbe–Schmitt reaction marked a significant advancement in the field of organic synthesis. It provided a practical method for the large-scale production of salicylic acid, which was previously difficult to synthesize efficiently. This reaction laid the groundwork for the development of non-steroidal anti-inflammatory drugs (NSAIDs) and other important medicinal compounds.

Animation of the Kolbe–Schmitt reaction

Related pages[edit]