What Is Organic Chemistry?

by Lucy Bell-Young

What is organic chemistry and how is it related to other STEM subjects? What is the importance of learning organic chemistry if you want to pursue a career in chemistry, and what are the applications of organic chemistry? These are some of the questions that this article will seek to answer.

Chalkboard with 'organic chemistry' written on, leaning against test tubes and molecular model

What Is Organic Chemistry And How Is It Related To Other Sciences?

Organic chemistry is an area of specialisation in chemistry that focuses on the study of compounds that contain carbon, like biological organisms. It’s specifically concerned with the molecular structure of these organic compounds, as well as their:

  • Composition
  • Various reactions
  • Chemical and physical properties
  • Laboratory or industrial preparations

Originally, organic chemistry was focused on substances that are only produced by living organisms, such as proteins, lipids, and carbohydrates. Over time, this subject has broadened its focus to include any compound that contains a carbon backbone, like: 

  • Hydrocarbons and their derivatives, like alcohols 
  • Synthetic or man-made products, like plastics
  • Compounds that contain things like nitrogen, oxygen, silicon, sulfur, or halogens 

Organic chemistry is not a foundational science like inorganic chemistry, because it deals with more complex substances. However, understanding it is a prerequisite to studying other sciences, like biochemistry or materials science. Students undertaking STEM education are similarly required to take at least one organic chemistry subject. In some cases, this subject is even taught to non-chemistry majors as a compulsory module part in general chemistry lessons.

Having a good grasp of organic chemistry will be very helpful later on in life if a student decides to pursue a STEM career. For example, a mechanical engineer who is designing a diesel engine will be able to produce a more efficient model if they have a strong understanding of how certain types of fossil fuels combust.

What Is The Importance Of Organic Chemistry?

Organic chemistry is not only important as an academic requirement for those majoring in STEM subjects, it’s also important because of its many practical applications in various industries, particularly in the processing and manufacture of a wide variety of consumer products, including:

  • Paper
  • Cosmetics
  • Processed foods
  • Pharmaceutical products

Even if you’re not a science major, and your interest is far removed from organic chemistry, you might benefit from knowing more about this subject without even realising. From the time you wake up in the morning to the time you go to sleep at night, there are products that we use everyday that are made possible because of organic chemistry. Whether it’s your toothpaste, shampoo, lotion, or gasoline, organic chemistry plays a huge role in making the manufacture of our everyday essentials possible. 

What Is Extraction In Organic Chemistry?

In organic chemistry, extraction is a laboratory or an industrial-scale method that mainly refers to the isolation of compounds from plant materials. Typically, liquids like fruit juice or essential oils are extracted from plants to make concentrated extracts, demonstrating how extraction moves organic plant compounds from one liquid solution to another. In this manner, compounds can be conveniently processed, studied, concentrated, or synthesised.

The extraction process allows a chemist to selectively separate and isolate desired compounds from a mixture. For example, essential oils from flowers can be extracted so that once their composition and structure are known, synthetic analogues can be made. Put simply, through extraction, the scents of flowers can be synthesised and used in things like perfumes and scented candles.

In terms of laboratory procedure, extraction usually involves the use of a separatory funnel. This is a relatively easy process that first requires the removal of the liquid from the solid parts of the plant. This can be done by pressing it or using a juicer. Once the liquid is extracted, it’s filtered in order to separate any solid residues. Then:

  • The liquid is poured into the separator funnel
  • An immiscibility solvent is added to separate the liquids in the mixture
  • The aqueous solution is then gradually allowed to drip until the oily or nonpolar liquid is left

Immiscibility is a property of substances, particularly liquids, that prevents certain combinations of substances from forming homogeneous mixtures, such as in the case of oil and water. Some examples of immiscibility solvents used in extractions are:

  • Water
  • Toluene
  • 2-propanol
  • 1-propanol
  • Methanol
  • Hexane
  • Heptane
  • Diethyl ether
Plant extraction
In organic chemistry, extraction is the isolation of compounds from plant materials

What Is The Mechanism In Organic Chemistry?

The mechanism in organic chemistry depends on which of the four types of reactions is taking place. A reaction mechanism refers to the orderly, step by step series of basic chemical reactions that need to occur in order for an overall and final reaction to happen. In organic chemistry, there’s a wide variety of complex chemical reactions occurring all the time, but they’re all examples of one of four types of reactions: substitution 1 (Sn1), substitution 2 (Sn2), elimination 1 (E1), or elimination 2 (E2).

Substitution 1 or Sn1

Substitution 1 reactions involve nucleophiles or bases. Reactions in this category will happen under two conditions: when a weak nucleophile or base is present, and when there’s a molecular fragment on the carbon chain. There are three steps involved in Sn1:

  1. Carbocation forms when the leaving group leaves
  2. The nucleophile attacks the carbocation
  3. Protons are removed from the nucleophile group (deprotonation)

Substitution 2 or Sn2

Chemical reactions in the Sn2 category are also substitution reactions. However, instead of a weak nucleophile or base, they involve a strong nucleophile. 

A reaction of this type happens if the leaving group is a primary group under the Sn1 reaction. Instead of a multi-step process, the reaction occurs as a single but concentrated step. Basically, the nucleophile attacks the primary or alpha carbon and at the same time removes the leaving group.

Elimination 1 or E1

An E1 reaction is also known as a unimolecular elimination because it involves the removal of one molecular group per molecular compound. Elimination 1 refers to the removal of an HX substituent that results in the formation of a double bond, making it very similar to an SN1 reaction.

Let’s take, for example, the reaction of propanol in sulphuric acid:

  • Step 1: The pentanol’s OH group receives a proton, turning it into water
  • Step 2: The newly formed water molecule leaves and takes electrons away. Carbocation is created as an intermediate on the attached carbon
  • Step 3: The beta carbon is then deprotonated by another water molecule. The beta carbon donates its electrons to the nearby single-bonded carbons (C-C). This results in a pi bond

Elimination 2 or E2

Secondary and tertiary alkyl halides commonly undergo E2 reactions. However, for this to happen, you’ll need a hindered base to react with a primary halide. 

An E2 reaction is a single step, concerted reaction that has one transition state. The rate of the reaction is governed by second order kinetics. It’s largely dependent on the type of base and alkyl halide. A pi bond is formed if the leaving molecular groups are coplanar. Meanwhile, the carbon atoms undergo hybridization states from sp3 to sp2.

Functional groups vector illustration
Organic chemistry studies any compound with a carbon backbone, from carbohydrates to hydrocarbons

What Is The Steric Factor In Organic Chemistry?

The way a group of molecules is packed together affects their structure and reactivity, and so the steric factor, also known as the steric effect, refers to how crowded molecules can be. When molecules are packed closely together, for instance, a significant increase in energy occurs. This means that some molecular groups are sterically shielded if large groups are present.

As an example, in a tert-butanol molecule, the central atom and alcohol group are shielded by the methyl groups. The methyl groups are bulky in this case, meaning that the alcohol group and the central carbon will be difficult to dislodge, making them more stable. 

What Is An Alkyl Group In Organic Chemistry?

In organic chemistry, an alkyl group is a functional group in an organic molecule that contains only carbon and hydrogen atoms, which are arranged as a carbon chain. 

An alkyl group serves as the basis for naming a particular organic compound that contains it. This is determined by the general formula for alkyls (CnH2n+1) as well as the specific compound that’s present. For example, the general formula for the alkyl group CH3 is named methyl because it’s derived from methane. Similarly, the alkyl group C2H5 is named butyl because it’s derived from butane.

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