This chapter is one of the most important chapters of the complete chemistry syllabus. Alcohols, phenols, and ethers are formed by replacing one or more hydrogen atom by a hydroxyl group(OH) and an alkoxy group(R-O), respectively. These are a very important class of compounds that we see around us every time and use in our daily life. There is one more class of organic compounds i.e, aldehydes, ketones and carboxylic acids. In this section, there are various important reactions that we study like Cannizzaro reaction, aldol condensation, Gattermann-Koch reaction, etc.
There are various important real-life applications that we see in our daily life. Some of them are mentioned below:
- Alcohols are used to make wine and beer.
- Ethanol burns as a fuel to form carbon dioxide and water. Using ethanol as a fuel has an advantage of less pollution.
- Acetone is used as a nail paint remover.
Important Topics - Organic Compounds containing Oxygen
- Physical Properties
- Chemical Reactions
- Important Questions
Overview of the Organic Compounds containing Oxygen
- From Alkenes: Alkene reacts with water in the presence of acid and forms alcohol. In the case of unsymmetrical alkenes, the alcohol is formed by following MArkovnikov's rule.
- From carbonyl compounds: LiAlH4 is a very strong reducing agent. We use this reagent to reduce carboxylic acids to primary alcohols.
- From haloarenes: In this reaction, chlorobenzene is used to react with NaOH at high temperature and pressure and sodium phenoxide is formed. This phenoxide is then acidified to produce phenol.
- From cumene: In this reaction, cumene is oxidised in the presence of air and thus converted to cumene hydroperoxide. Now, this hydroperoxide is treated with dilute acid and thus phenol is formed.
- Dehydration of alcohols: In this reaction, alcohol is dehydrated to ether in the presence of an acid like H2SO4 at 413K.
- Williamson synthesis: In this reaction, phenol is treated with sodium hydroxide and forms sodium phenoxide. This phenoxide is then converted to ether.
- Dehydration: In this reaction, alcohol is dehydrated in the presence of an acid and form alkene at 443K.
- Acylation of alcohols: In this reaction, alcohol is treated with an acyl group in the presence of pyridine and form the product as shown below:
- Electrophilic aromatic substitution: Phenol, when treated with dilute HNO3 at low temperature produces ortho and para nitrophenols.
- Kolbe's reaction: In this reaction, phenol is treated with sodium hydroxide and forms phenoxide. This phenoxide is then treated with carbon dioxide and thus forms hydroxybenzoic acid.
- Reimer-Tiemann reaction: In this reaction, phenol is treated with chloroform in the presence of sodium hydroxide then a CHO group is attached at the ortho position of phenol and thus forms salicylaldehyde.
- Cleavage of C-O bond in ethers: In this reaction, ether is treated with hydrogen iodide and thus forms the alcohol and tertiary halide.
- Friedel-Crafts reaction: In these reactions, anisole is treated with alkyl and acyl groups and thus the alkyl and acyl groups are attached at the ortho and para positions as shown in the reaction. This reaction occurs in the presence of catalysts known as anhydrous aluminum chloride
- Nitration: In this reaction, anisole is treated with a mixture of concentrated sulphuric acid and nitric acid and thus produces a mixture of ortho and para nitroanisole.
ALDEHYDES KETONES AND CARBOXYLIC ACIDS
- From acyl Chloride: In this reaction, acyl chloride is treated with hydrogen in the presence of palladium-barium sulphate as a catalyst. This reaction is also known as 'Rosenmund reduction'.
- Gatterman - Koch reaction: In this reaction, benzene is treated with carbon monoxide and hydrogen chloride in the presence of anhydrous aluminum chloride and thus the product formed is benzaldehyde. This reaction is also known as Gatterman-Koch reaction.
- From Nitriles: The nitrile is treated with the Grignard reagent and the product formed is a ketone.
- Friedel-Crafts Acylation reaction: In this reaction, benzene or substituted benzene is treated with an acyl chloride in the presence of anhydrous aluminum chloride and a ketone is formed as a product. This reaction is also known as Friedel-Crafts Acylation reaction.
- From primary alcohols: Primary alcohols are oxidised to corresponding carboxylic acids in the presence of some oxidising agents such as alkaline KMnO4.
- From Esters: Acidic hydrolysis of esters gives corresponding carboxylic acids as shown in the reaction below.
- Clemenson’s Reduction: In this reaction, aldehydes or ketones are treated with zinc amalgam and concentrated hydrochloric acid. Thus, the carbonyl group of aldehydes and ketones is reduced to CH2. This reaction is also known as Clemenson’s Reduction:
- Intermolecular Aldol Condensation: In this reaction, two different aldehyde compounds are reacted with each other in the presence of sodium hydroxide and the different products are formed as shown in the reaction.
- Intramolecular Aldol Condensation: In this reaction, the compound reacts within itself in the presence of a base as shown in the reaction.
- Intermolecular Cannizzaro reaction: In this reaction, two aldehyde compounds react with each other in the presence of sodium hydroxide and produce alcohol and a carboxylic acid salt.
- Benzoin Condensation: This is a condensation reaction. It occurs between two aromatic aldehydes and produces an acyloin.
- Reduction: In this reaction, carboxylic acids are reduced to amides in the presence of ammonia.
- Decarboxylation: In this reaction, carboxylic acids are reduced to corresponding alcohols in the presence of LiAlH4. These alcohols can be further reduced to hydrocarbons when their sodium salts are heated with sodalime.
- Electrophilic Substitution: Aromatic carboxylic acids undergo electrophilic substitution reaction. In these reactions, the carboxyl group acts as a meta directing group.
How to prepare for Organic compounds containing oxygen?
This chapter is part of organic chemistry. It is completely theory-based. You are not supposed to memorize any formula and numerical practice for getting the good hold on this chapter. All you just need to remember is reaction mechanisms and important reactions.
For this chapter, first, you must have your basic concepts completely clear that you can learn from the "Some basic principles of Organic Chemistry". For this, you must go through Unit 12 of the NCERT book 11th class part II thoroughly.
- In the nutshell, it can be said that although this chapter is lengthier than other chapters, it is a very simple and straightforward one. So always say a "Big YES" to this chapter.
For this chapter, first, the NCERT book is best for initial level preparation as well as for board exams. Now, after this, if you want to prepare for competitive exams like JEE and NEET, then these are the best books for you - O.P Tandon and R.K Gupta by Arihant publication. Meanwhile, in the preparation, you must continuously give the mock tests for the depth of knowledge. Our platform will help you to provide with the variety of questions for deeper knowledge with the help of videos, articles and mock tests.
Chemistry Chapter- wise Notes for Engineering and Medical Exams