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Another Name For A Condensation Reaction: Condensation reactions are also known by another name dehydration synthesis reactions. This is because they contain the combining of molecules with the removal of water. Dehydration represents the loss of water, while synthesis represents creation. When glucose molecules associate to form starch, it is an example of dehydration synthesis. Condensation reaction, any of a class of reactions in which two molecules associate, usually in the existence of a catalyst, with the elimination of water or some other simple molecule.
The combination of two alike molecules is known as self-condensation. Aldehydes, esters, ketones, alkynes, and amines are among genuine organic compounds that join with each other and, except for amines, among themselves to form broader molecules, many of which are useful intermediate compounds in organic syntheses. Catalysts generally used in condensation reactions consist of acids, bases, complex metal ions, and the cyanide ion.
Condensation Reactions or Dehydration Synthesis Reactions
In the condensation reaction, two molecules relate to form a single molecule. A small molecule, often water, is generally wiped out during a condensation reaction.
Amino Acids Tie Together To Form A Molecule Called A Dipeptide Amino acids are leady biological molecules that have an amine functional group on one end and a carboxylic acid functional group on the other end. When two amino acids associate in a condensation reaction, a covalent bond forms between the amine nitrogen of one amino acid and the carboxyl carbon of the second amino acid. A molecule of water is then eliminated as a second product.
In Other Words, We Can Understand As
A condensation reaction is a chemical reaction to attach covalently resulting molecules in the fillers’ surface, during which two molecules (functional groups) associate together to form one single molecule with a loss of entropy.
In the case of graphene, condensation occurs via two reactive oxygenated groups (hydroxyl and carboxyl functionalities) present on graphene sheets with isocyanate, diisocyanate, and amine compounds through an amidation reaction, getting to the formation of the amides and carbamate ester linkages. An example of a condensation reaction is using a series of isocyanate compounds in the surface modification of graphene oxide.
Aldol Condensation
Aldol condensation appears in aldehydes having α-hydrogen with a dilute base to give β–hydroxy aldehydes called aldols. This reaction is most generally known as aldol condensation. If the condensation reaction appears between two different carbonyl compounds it is called crossed aldol condensation.
Aldol Condensation can be explained as an organic reaction in which enolate ion reacts with a carbonyl compound to form β–hydroxy ketone or β-hydroxy aldehyde, followed by dehydration to give a conjugated enone. Aldol Condensation plays a key role in organic synthesis, creating a path to form carbon-carbon bonds.
Mechanism
One of the normal examples for base-catalyzed aldol condensation is described below in which catalyst normally used is hydroxide ion.
Step: 1
In reverse order, The hydroxide ion deprotonates the aldehyde
Step: 2
Enolate ion 1 attacks to the unreacted aldehyde
Step: 3
Alkoxide ion 2 is protonated
Step: 4
A small amount of aldol is transformed into enolate ion (4) due to hydroxide ion.
Step: 5
Here Enolate Ion(4) eliminates a hydroxide ion.
Crossed Aldol Condensation
The condensation reaction between two distinct molecules of an aldehyde or ketone in an aprotic solvent such as water or alcohol empowers the crossed aldol reaction. When condensation is between two different carbonyl compounds, it is called crossed aldol condensation.
When both aldehydes have alpha hydrogens, both can form carbanions and can also perform as carbanion acceptors. Hence a mixture of four products is developed which has little synthetic value. If one of the aldehydes has no alpha hydrogen then it can act only as a carbanion acceptor.
In such a case, only two products are formed. A common substrate for the crossed aldol reaction is an aromatic aldehyde, which has no alpha position. Furthermore, dehydration of the basic condensation product is speedy which leads to the evolution of the α, β – unsaturated ketone, and prevents the retro-aldol reaction from taking place.
Claisen condensation
The Claisen condensation is a carbon-carbon bond generating reaction that appears between one ester and another carbonyl compound or two esters in the existence of a strong base, resulting in a β-keto ester or a β-diketone. It is designated after Rainer Ludwig Claisen, who first disclosed his work on the reaction in 1887.
Perkin Reaction
It is an organic chemical reaction that was invented by William Henry Perkin, an English chemist scientist. This reaction provides an α,β -unsaturated aromatic acid. Perkin reaction mechanism consists of the reaction between aromatic aldehydes, the aliphatic acid anhydride, and the alkali salt of the acid to deliver cinnamic acid derivatives.
