Destructive Distillation – Definition, Diagram, Process, And Applications
What is Destructive Distillation?
In this article, readers will be able to learn about the topic of destructive distillation. We will answer the question of what is destructive distillation by first beginning with the definition of destructive distillation. We will also explore other facets of the destructive distillation meaning.
When it comes to the definition of destructive distillation, then it can be said that this is a chemical process that is used to subject unprocessed materials to decomposition. This is done by heating those unprocessed materials. In this process, ‘cracks’ are produced in relatively large quantities.
It is also important to point here that usually, the term ‘destructive distillation’ is used to refer to the process through which organic materials are processed with certain reagents, limited amounts of oxygen, solvents, and catalysts like steam and phenols.
The destructive distillation definition can also be used to refer to the processing of organic materials in an environment that does not contain air or pyrolysis in the absence of air. One can also define destructive distillation as the application of the concepts of pyrolysis.
For students who are unfamiliar with the term, pyrolysis can be explained as the process of thermal decomposition of various substances. This is done at a very high temperature and under relatively inert atmospheres.
Let’s consider an example to understand this entire process in a better manner. Coal is often subjected to destructive distillation. This is done to form a wide range of products that are very important from a commercial point of view. Some of those commercially important products are coke, coal tar, coal gas, gas carbon, ammonium hydroxide, and coal oil.
Destructive Distillation of Coal Diagram
As of now, students must have learned how to define destructive distillation and learned the destructive distillation meaning. However, there might still be some doubts related to the destructive distillation definition.
To further solve these doubts, we believe that it is best for students to go through the destructive distillation of coal diagrams. Check the below diagram.
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Products Formed During Destructive Distillation
Have you ever wondered about what products are formed during destructive distillation? If you have, then in this section, you will be able to find the answer to the question of what are the products formed during destructive distillation.
The first thing that students need to learn about the products that are formed during destructive distillation is that in the case of inorganic materials, only a few products are generated. This is directly in contrast to the large number of products that are generated after processing organic materials through destructive distillation.
However, one must also remember that most of those products are not of major importance from a commercial point of view. Another important fact that one must know is that the distillates of destructive distillation processes often have a relatively low molecular weight.
There are also fractions of distillates that can go under the process of polymerization to form larger molecules. Tar and chars are good examples of products that can go under polymerization to form larger molecules. Both of these products are also stable under heat.
It is also important to note that the cracking of larger molecules in the feedstock and the further conversion of those compounds into volatile liquids and products, the polymerization of distillate molecules, and the formation of chars and solids can all occur during the same process. These products have great commercial value.
The process of destructive distillation and other forms of pyrolysis has helped in discovering new chemical compounds. These processes have also helped in the elucidation of chemical structures of different compounds.
Through these processes, chemists have also learned about the nature of several chemical materials. A good example of this is how insight was gained into the structures of furanoses and pyranoses.
The Process of Destructive Distillation
In this section, we will look at the process of destructive distillation. As we have mentioned before, this process involved the pyrolysis of organic and inorganic feedstock. This is done inside a distillation apparatus, and the volatile products are collected during the pyrolysis.
However, it is important to note here that only a fraction of the mass of the initial feedstock will be accounted for in the final products. This is mainly because a large portion of the initial feedstock is still retained by the distillation apparatus. This is usually in the form of ash, char, and non-volatile tar.
Further, if this process is compared with combustion, then a significantly lower amount of the organic matter is consumed during the entire process. Some experts also view this entire process as a modified version of the traditional practice of charcoal burning.
It is also vital to note the importance of this process in the industrial setting in many regions of the world - however, the most prominent place where this practice is performed in Scandinavia. Thankfully, modern destructive distillation processes have also been better optimized to maximize the number of valuable products extracted from the feedstock.
Application of Destructive Distillation
To help learners, we have created a list of various applications of destructive distillation. That list is mentioned below.
This process can be used to obtain both turpentine and methanol from wood
The destructive distillation of wood also tends to behind a residue of solid charcoal. This substance has a lot of commercial applications
Processing wood through destructive distillation can also help one to obtain many other products that have a high commercial value. Some of those products are tar and terpenes
Coal is processed through destructive distillation to obtain several commercially valuable products like ammonium hydroxide, coke, coal tar, and coal gas
The waste obtained after polymerization can also be processed through destructive distillation. This process will give up the initial monomers, and those monomers can be reused in other proper procedures
Fun Facts about Destructive Distillation
Did you know that destructive distillation as a process has been used time and again to find various organic compounds? This statement is a fact as destructive distillation was used to discover isoprene.
Isoprene was discovered when natural rubber was processed through destructive distillation. Isoprene plays an important role in the formation of many synthetic rubbers. The most important synthetic rubber produced by using isoprene is neoprene.
FAQs on Destructive Distillation
1. What is destructive distillation?
Destructive distillation is a chemical process that involves heating a complex organic substance, such as coal or wood, to a very high temperature in the absence of air. This breaks down the substance into simpler, more valuable products through thermal decomposition, rather than allowing it to burn.
2. What happens during the destructive distillation of coal?
When coal is heated to approximately 1000°C in a closed container without air, its complex molecular structure breaks down. This process separates the volatile components, which turn into gas and vapour, from the solid, non-volatile residue. The resulting products are then collected and separated.
3. What are the main products obtained from the destructive distillation of coal?
The destructive distillation of coal, as per the CBSE curriculum, yields four primary products:
- Coke: The solid, porous, and almost pure carbon residue used as a fuel and a reducing agent in metallurgy.
- Coal Tar: A thick, black, viscous liquid that is a source of many organic compounds like benzene, naphthalene, and phenol.
- Coal Gas: A flammable gaseous fuel, which is a mixture of hydrogen, methane, and carbon monoxide.
- Ammoniacal Liquor: A solution of ammonia compounds in water, used to produce nitrogenous fertilisers like ammonium sulphate.
4. How is destructive distillation different from fractional distillation?
The fundamental difference is that destructive distillation is a chemical decomposition process, while fractional distillation is a physical separation process. Destructive distillation breaks down a substance into entirely new chemical products. Fractional distillation, on the other hand, separates a mixture of liquids based on differences in their boiling points without changing their chemical identity, such as in the refining of crude oil.
5. What is the role of the 'absence of air' in destructive distillation?
The absence of air, specifically oxygen, is critical because it prevents combustion. If oxygen were present, the organic material would simply burn upon heating, producing ash, carbon dioxide, and water. By excluding air, the high temperature forces the chemical bonds within the substance to break, leading to its decomposition into valuable industrial products instead.
6. Why is destructive distillation considered an important industrial process?
Destructive distillation is industrially important because it efficiently converts a single low-value raw material, like coal, into multiple high-value products. For instance, the coke produced is essential for steel manufacturing, while coal tar serves as a raw material for producing dyes, drugs, plastics, and explosives. This process maximises the economic value extracted from natural resources.
7. What is the main difference between pyrolysis and destructive distillation?
While the terms are closely related, pyrolysis is the broader scientific term for the thermal decomposition of materials at high temperatures in an inert atmosphere. Destructive distillation is a specific type of pyrolysis where the primary goal is to heat a substance to break it down and then collect and separate the volatile products into useful liquid and gaseous fractions.
8. Besides coal, what are other examples of destructive distillation in practice?
A classic example is the destructive distillation of wood, which is used to produce charcoal (the solid residue), wood tar, pyroligneous acid (containing acetic acid and methanol), and wood gas. The process can also be applied to other forms of biomass, oil shale, and even certain types of plastic waste to convert them into fuel and chemical feedstocks.
