Misplaced Pages

Condensation reaction: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editContent deleted Content addedVisualWikitext
Revision as of 16:56, 25 January 2017 editA876 (talk | contribs)Extended confirmed users10,121 edits →Condensation polymerization: +link. wording.← Previous edit Latest revision as of 17:03, 23 December 2024 edit undoDirac66 (talk | contribs)Extended confirmed users17,916 editsm Undid revision 1264792856 by 106.219.195.203 (talk) Restore formatting of referenceTag: Undo 
(100 intermediate revisions by 46 users not shown)
Line 1: Line 1:
{{short description|Chemical reaction in which two molecules are combined and a small molecule, usually water, is lost}}
⚫ ]s to form a ] (red) with expulsion of water (blue)]]
A '''condensation reaction''' is a ] in which two ]s or ], often ]s, combine to form a larger molecule, together with the loss of a small molecule.<ref name=goldbook>{{GoldBookRef|title=Condensation Reaction|file=C01238|year=1994}}</ref> Possible small molecules that are lost include ], ], ], or ], but most commonly in biological reactions it is water.


In ], a '''condensation reaction''' is a type of ] in which two ]s are ] to form a single molecule, usually with the loss of a small molecule such as ].<ref>{{cite book |title=Book: Introductory Chemistry (CK-12) |date=12 August 2020 |publisher=Chemistry Libre Texts |url=https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Introductory_Chemistry_(CK-12)/25%3A_Organic_Chemistry/25.18%3A_Condensation_Reactions |access-date=9 January 2021 |chapter=25.18 Condensation Reactions}}</ref> If water is lost, the reaction is also known as a ]. However other molecules can also be lost, such as ], ], ] and ].<ref>{{cite journal|url=https://goldbook.iupac.org/html/C/C01238.html|title=Condensation Reaction|website=IUPAC Compendium of Chemical Terminology (Gold Book)|year=2014|publisher=IUPAC|doi=10.1351/goldbook.C01238|access-date=7 December 2017|doi-access=free}}</ref>
When two separate molecules react, the condensation is termed intermolecular. A simple example is the condensation of two ]s to form the ] characteristic of ]s. This reaction example is the opposite of ], which splits a chemical entity into two parts through the action of the polar ], which itself splits into ] and ] ions. Hence ] is required to form ]s via condensation.


The addition of the two molecules typically proceeds in a step-wise fashion to the addition product, usually in ], and with loss of a water molecule (hence the name ]).<ref>{{Cite journal|last=Fakirov|first=S.|date=2019-02-01|title=Condensation Polymers: Their Chemical Peculiarities Offer Great Opportunities|journal=Progress in Polymer Science|volume=89|pages=1–18|doi=10.1016/j.progpolymsci.2018.09.003|s2cid=105101288|issn=0079-6700}}</ref> The reaction may otherwise involve the ]s of the molecule, and is a versatile class of reactions that can occur in ]ic or ] conditions or in the presence of a ]. This class of reactions is a vital part of life as it is essential to the formation of ]s between ]s and to the ].<ref>{{Cite book|title=Fundamentals of Biochemistry|url=https://archive.org/details/fundamentalsbioc00voet|url-access=limited|last1=Voet|first1=Donald|last2=Voet|first2=Judith|last3=Pratt|first3=Chriss|publisher=John Wiley & Sons, Inc.|year=2008|isbn=978-0470-12930-2|location=Hoboken, NJ|pages=}}</ref>
If the union is between ]s or groups of the same molecule, the ] is termed "intramolecular condensation", which in many cases leads to ]. An example is the ], in which the two ] groups of a single diester molecule react with each other to lose a small ] molecule and form a β-ketoester product.


⚫ ].]]
]


Many variations of condensation reactions exist. Common examples include the ] and the ], which both form water as a by-product, as well as the ] and the ] (intramolecular Claisen condensation), which form alcohols as by-products.<ref name=":0">{{cite book|title=Advanced Organic Chemistry|url=https://archive.org/details/advancedorganicc00bruc|url-access=limited|last1=Bruckner|first1=Reinhard|date=2002|publisher=Harcourt Academic Press|isbn=0-12-138110-2|edition=First|location=San Diego, California|pages=–427}}</ref>
==Mechanism==
Many condensation reactions follow a ] or an ] ]. Other condensations, such as the ] are triggered by ] or ] conditions.


]
==Condensation polymerization==
In condensation ] or "]", multiple condensation reactions take place, joining ]s and ] into long chains called ]s. It occurs for example in the synthesis of ]s or ]s. It can be homopolymerization of a single monomer A-B with two different end groups that condense, or ]ization of two co-monomers A-A and B-B.


== Synthesis of prebiotic molecules ==
Condensation polymerization releases multiple small molecules, in contrast to ] reactions, which do not. In general, ]s form more slowly than ]s, often requiring ]. They are generally lower in molecular weight. Monomers are consumed early in the reaction; the terminal ]s remain active throughout; and short chains combine to form longer chains. A high conversion rate is required to achieve high molecular weights, per ].
{{main|Abiogenesis}}

Condensation reactions likely played major roles in the synthesis of the first biotic molecules including early ]s and ]s. In fact, condensation reactions would be required at multiple steps in ] oligomerization: the condensation of ]s and ]s, ] ], and ] polymerization.<ref name=":02">{{Cite book |last=Fiore |first=Michele |title=Prebiotic Chemistry and Life's Origin |publisher=Royal Society of Chemistry |year=2022 |isbn=9781839164804 |location=United Kingdom |pages=124–144}}</ref>
] monomers lead to linear chains, and therefore ] polymers, but, when the monomer ] exceeds two, the product is a ] that may be a ].

==Applications==
The reactions that form ] from their constituent acids are typically condensation reactions.

Condensation polymerization produces many important ]s, for example: ], ], and other ]s and various ]. It is also the basis for the laboratory formation of ]s and ]s.

Many biological transformations are condensation reactions. ], ] synthesis, ] syntheses, ], and ] are a few examples. A large number of such reactions are used in synthetic ]. Other examples include:
*]
*]
*]
*]
*] (glycidic ester condensation)
*]
*]
*]
*]
*]
*] or symmetrical aldol condensation
*]

Some reactions that are called "condensation reactions" for historical reasons, are actually ]s:
*]<ref name=goldbook/>


==See also== ==See also==
*] * ]
*], the opposite of a condensation reaction * ], the opposite of a condensation reaction
*]s * ]s


==References== ==References==
{{Reflist}} {{Reflist}}

{{Authority control}}


] ]

Latest revision as of 17:03, 23 December 2024

Chemical reaction in which two molecules are combined and a small molecule, usually water, is lost

In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a dehydration synthesis. However other molecules can also be lost, such as ammonia, ethanol, acetic acid and hydrogen sulfide.

The addition of the two molecules typically proceeds in a step-wise fashion to the addition product, usually in equilibrium, and with loss of a water molecule (hence the name condensation). The reaction may otherwise involve the functional groups of the molecule, and is a versatile class of reactions that can occur in acidic or basic conditions or in the presence of a catalyst. This class of reactions is a vital part of life as it is essential to the formation of peptide bonds between amino acids and to the biosynthesis of fatty acids.

Idealized scheme showing condensation of two amino acids to give a peptide bond.

Many variations of condensation reactions exist. Common examples include the aldol condensation and the Knoevenagel condensation, which both form water as a by-product, as well as the Claisen condensation and the Dieckman condensation (intramolecular Claisen condensation), which form alcohols as by-products.

Aldol condensation overview

Synthesis of prebiotic molecules

Main article: Abiogenesis

Condensation reactions likely played major roles in the synthesis of the first biotic molecules including early peptides and nucleic acids. In fact, condensation reactions would be required at multiple steps in RNA oligomerization: the condensation of nucleobases and sugars, nucleoside phosphorylation, and nucleotide polymerization.

See also

References

  1. "25.18 Condensation Reactions". Book: Introductory Chemistry (CK-12). Chemistry Libre Texts. 12 August 2020. Retrieved 9 January 2021.
  2. "Condensation Reaction". IUPAC Compendium of Chemical Terminology (Gold Book). IUPAC. 2014. doi:10.1351/goldbook.C01238. Retrieved 7 December 2017.
  3. Fakirov, S. (2019-02-01). "Condensation Polymers: Their Chemical Peculiarities Offer Great Opportunities". Progress in Polymer Science. 89: 1–18. doi:10.1016/j.progpolymsci.2018.09.003. ISSN 0079-6700. S2CID 105101288.
  4. Voet, Donald; Voet, Judith; Pratt, Chriss (2008). Fundamentals of Biochemistry. Hoboken, NJ: John Wiley & Sons, Inc. pp. 88. ISBN 978-0470-12930-2.
  5. Bruckner, Reinhard (2002). Advanced Organic Chemistry (First ed.). San Diego, California: Harcourt Academic Press. pp. 414–427. ISBN 0-12-138110-2.
  6. Fiore, Michele (2022). Prebiotic Chemistry and Life's Origin. United Kingdom: Royal Society of Chemistry. pp. 124–144. ISBN 9781839164804.
Category: