[Chemistry Class Notes] on Dehydration Synthesis Pdf for Exam

Starch is quite crucial for our body but do you know how our body makes its starch? Well, for starters dehydration synthesis is the reaction which provides us with the starch that is necessary for our body to work correctly. Just like that, there are many uses of dehydration synthesis and many ways to do it. Today we are going to answer the following questions: what is a dehydration reaction, what are its applications and how to perform its chemical reaction. 

Dehydration Reaction

The first thing that comes to mind when you hear or read the word “dehydration” is the removal of water from a given object or a reaction. Dehydration synthesis occurs when there is a loss of water molecule for the formation of a larger molecule with the help of small reactants. Most of the dehydration synthesis that we see occur in nature forms a biological polymer where we get to see the addition of individual monomers along with the elimination of a single molecule of water. 

On the other hand, just like dehydration reaction condensation reaction works in the same way. In a condensation reaction, two molecules come together to provide a new compound, and the water molecule present in between them gets lost to form a larger molecule. You can use dehydration and condensation interchangeably.

Now let’s find out what happens when a dehydration reaction takes place in a given chemical system. 

Dehydration Synthesis of 2 Amino Acids

This is the basic structure of amino acids given in the diagram, which is shown in a picture below. Here we have two amino acids which are NH₂ and COOH. In addition to this, our body’s second most abundant material is amino acids. These acids have two functional groups and building blocks to the proteins that are present inside our body. The amino acid uses protein dehydration synthesis to give our body the required proteins so it can work properly. 

(example of amino acids, here we have NH₂ and amine group along with carboxyl group)

In the given image, you can see R in a box; it means a residual group is also present, which is a combination of individual elements that are attached here. As a result, amino acids are given different properties. This clears your definition for the synthesis reaction

When the dehydration of two amino acids takes place, the first amino acid releases oxygen that combines with the two hydrogen molecules present in the second amino acid. Thus, we get a covalent bond which links up the two monomers to form a dipeptide. During this process of dehydration synthesis water molecules are formed. 

Some of the reactions that you are going to perform under dehydration synthesis can be reversed if needed. Meaning if they are forming a mixture by using two different elements, you can get these two elements separated once again by performing a reversible reaction process. 

The most common reversible reaction to dehydration synthesis is hydrolysis in which we get H₂O which is taken away during the dehydration synthesis. 

Protein Dehydration Synthesis

There are several ways to define different dehydration chemistry synthesis. We can easily group them based on their reactants. Some of the elements that perform the synthesis have two functional groups. These two can react with each other quickly, a quick example of these reactions were the ones we showed you in the above image of two amino acids that are working as a functional group to make the reaction possible. 

The amino acid from the amine group can undoubtedly react to lots of acid groups to form amide bond, which is covalent. In addition to this, the newly formed acid still contains one free amine group along with one free carboxylic acid. Thus, making sure the reaction will proceed further with more amino acids. 

Another way to classify the dehydration synthesis is by separating it with the nature of the different catalysts. Just take an example of symmetrical ethers. In these, we have hydrogen ions which are working as a catalyst. The main reason why reactions need catalysts is because in living organisms when the reaction is taking place, the pH, temperature and salt concentration can be tweaked. As a result, for a reaction to complete and give its product in a short time, we need a catalyst.