Dehydration synthesis is a chemical process where two smaller molecules are combined by removing elements from each of these molecules.
Based on the structure of hydrocarbons, organic compounds can be divided into aliphatic and
. Organic compounds can undergo various types of chemical reactions which result in the formation of new compounds due to changes in bonding between atoms.
Some chemical reactions result in a single molecule, while others involve displacement or substitution of atoms. Synthesis or combination reactions involve the merging of two substances to form one molecule. An example is the combination of Mg and O
to form MgO (magnesium oxide).
Contrastingly, decomposition reactions involve a substance breaking down into more than one substance, like the decomposition of a water molecule into H
. Another type of reaction is displacement reactions which can be single or double displacement. They involve the swapping of one or more parts of compounds with each other. Common organic reactions include addition, substitution, rearrangement, elimination, and oxidation-reduction reactions.
"Dehydration reactions are chemical reactions that eliminate a water molecule from the reactant molecule. Dehydration synthesis is the process where two molecules combine with the removal of a water molecule."
The term dehydration is used for
and synthesis represents the creation of a new substance. Hence, dehydration synthesis refers to the removal of water while forming new compounds. It is evident that the combination of two molecules will form a larger compound and water molecules will be eliminated as a by-product during the reaction.
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Substitution reactions are common reactions of alkanes, haloalkanes, and other organic compounds. These reactions involve the substitution of one of the atoms of the molecule, leaving the group in the presence of either a nucleophile or an electrophile.
Unlike substitution reactions, elimination reactions involve the removal of certain atoms in the form of good leaving groups such as water, halogens, etc. For instance, the elimination of water molecules from alcohol forms alkene, which is an example of a dehydration reaction.
Similarly, the elimination of hydrogen molecules forms unsaturated compounds and is known as a dehydrogenation reaction. Rearrangement reactions do not eliminate or add any atom but only rearrange the molecule to form a new one. Addition reactions involve the addition of some atoms over multiple chemical bonds.
Examples of Dehydration Synthesis Reaction
1. Biochemical reactions serve as perfect examples of dehydration synthesis reactions. Amino acids, the building blocks of proteins, polymerize to form peptides and polypeptides. Amino acids have two
; amino -NH
and carboxylic group (-COOH). They react to form an amide linkage (-CO-NH-) with the elimination of water molecules.
Hence, peptide formation is an example of a dehydration synthesis reaction.
2. The formation of polysaccharides is another example of dehydration synthesis. Monosaccharides, the monomer units for polysaccharides, are polyhydroxy
. Monosaccharides are bonded with each other through a glycosidic linkage. This linkage is formed by the reaction of –OH groups of two monomer units with the elimination of water molecules.
The formation of maltose is an example of a dehydration synthesis reaction. Two alpha-glucose units form a glycosidic linkage with the elimination of water molecules to form one maltose molecule.
Therefore, we can conclude that a dehydration synthesis process always involves two steps.
Creation of a new product
Loss of a water molecule
The Process of a Dehydration Synthesis Reaction
Dehydration synthesis reactions are
combination or synthesis reactions
that occur between the same or different monomer units with the elimination of water molecules. It is a type of condensation reaction where water molecules are eliminated during the addition of two molecules.
As each step involves the elimination of water molecules, the reaction is termed a dehydration reaction. Since it results in the creation of a new substance, it is referred to as a
dehydration synthesis reaction
Many biochemical reactions occur through dehydration synthesis mechanisms. For instance, the formation of peptides from amino acids is a dehydration synthesis reaction.
This is a peptide bond formation reaction that occurs between two amino acid molecules.
The amino group of one molecule and the carboxyl group of another molecule condense with the elimination of water molecules to form an amide linkage in the dipeptide.
Dehydration Synthesis and Hydrolysis
Dehydration synthesis involves the creation of new chemical bonds between two molecules, leading to the formation of new compounds.
A reaction occurs with the loss of water molecules at each step.
The loss of water molecules can occur due to reactions between two functional groups like –OH, -NH
or –COOH. It is
also referred to as a condensation reaction.
are good examples of dehydration synthesis reactions where monomer units condense together to form polymers.
The formation of disaccharides from monosaccharides in carbohydrates, the formation of lipids with one glycerol and three molecules of fatty acids are examples of dehydration synthesis.
Similarly, the formation of nucleic acid from nucleotides is also an example of dehydration synthesis.
Hydrolysis can be seen as the reverse reaction of a dehydration synthesis reaction. It involves the addition of water molecules with the cleavage of bonds to form more than one substance from one substance.
In other words, hydrolysis is a chemical reaction that breaks a molecule into smaller units by the addition of water molecules.
For example, hydrolysis of polymers results in the formation of monomer units as it breaks the connections between monomer units.
For instance, hydrolysis of a disaccharide forms monosaccharide units. Similarly, the hydrolysis of lipids results in the formation of glycerol and fatty acids.
Dehydration reactions can be defined as the chemical reactions in which a water molecule is eliminated from the reactant molecule. The process of combination of two molecules with the elimination of water molecules is called dehydration synthesis.
What is a substitution reaction?
Substitution reactions are the most common reactions of alkanes, haloalkanes and other organic compounds. These reactions involve the substitution of one of the atoms of the molecule as leaving the group in the presence of either nucleophile or electrophile.
What happens in a dehydration synthesis reaction?
Dehydration synthesis reactions are combination or synthesis reactions which occur between the same or different monomer units with the elimination of water molecules. It is a kind of condensation reaction in which water molecules are eliminated with the addition of two molecules.
What is the difference between dehydration synthesis and hydrolysis?
Dehydration synthesis involves the formation of new chemical bonds between two molecules which leads to the formation of new compounds with the loss of water molecules. Hydrolysis, on the other hand, is a chemical reaction which splits a molecule into smaller units by the addition of water molecules.