What is Alcohol in Chemistry?
Alcohol is an organic molecule with at least one hydroxyl functional group (OH) bonded to a saturated carbon atom, per chemistry.
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Alcohol is a homologous series of molecules with a hydroxyl functional group (-OH). The general formula for alcohols is CnH2n+1OH. Alcohols are hydrocarbon molecules that have one or two hydroxyl groups in place of one or more hydrogen atoms.
Types of Alcohols – Primary, Secondary, and Tertiary Alcohols
Three types of alcohol exist: primary, secondary, and tertiary. There are three classifications of alcohol: primary, secondary, and tertiary. The hydroxyl group is categorized according to where the carbon atom of an alkyl group is attached to it.
In chemistry, an alcohol is produced when the hydrogen atom in a hydrocarbon is replaced by a hydroxyl group consisting of two oxygen and hydrogen atoms. Alcohols create secondary alcohols when they interact with other atoms.
Oxidation of Alcohols
In organic chemistry, alcohol oxidation is an essential process. When primary alcohols are oxidized, aldehydes and carboxylic acids are created; when secondary alcohols are oxidized, ketones are produced. In contrast, tertiary alcohols cannot be oxidized without disrupting the C–C bonds inside the molecule.
1. Oxidation of Primary Alcohols
Carboxylic Acids are produced from the oxidation of primary alcohols or aldehydes. Typically, potassium dichromate(VI) solution oxidizes primary alcohols and aldehydes to carboxylic acids in the presence of dilute sulfuric acid. During the reaction, the potassium dichromate(VI) solution turns from orange to green.
2. Oxidation of Secondary Alcohols
When secondary alcohol is oxidized, a ketone is formed. Hydrogen from the hydroxyl group is lost together with the hydrogen linked to the second carbon. The remaining oxygen creates double bonds with the remaining carbon. As R1–COR2 reacts, ketone is produced. Without breaking carbon-carbon bonds, secondary alcohols can be quickly oxidized to the ketone level. Except under extreme conditions, there is no additional oxidation.
In the following example, the oxidation of propan-2-ol (secondary alcohol) to propanone (ketone) is described.
3. Oxidation of Tertiary Alcohols
Tertiary alcohols (R3COH) are resistant to oxidation because the carbon atom that contains the OH group is not connected to a hydrogen atom but is instead bound to other carbon atoms.
Carbon-to-hydrogen bonds are easily broken under oxidative circumstances, whereas carbon-to-carbon bonds are not.
Dehydration of Alcohols
Dehydrogenation is a crucial process in petroleum chemistry because it transforms inert alkanes into olefins and aromatic compounds, which serve as precursors for various functional groups.
Typically, alcohol dehydration involves the breaking of a C-O bond and the loss of a proton from the beta position.
Dehydration of secondary and tertiary alcohols leads to the creation of a chemical known as the carbo cation intermediate.
The diagram below illustrates the general dehydration reaction of alcohols:
Esterification of Alcohols
In esterification, two reactants (often an alcohol and an acid) combine to form an ester as the reaction result. In addition to being widely employed in organic chemistry and biological materials, esters have a pleasant fruity aroma.
Alcohols react with a number of acids to generate esters. Fischer’s esterification is defined by the acid-catalyzed reaction of an alcohol and an acid to create an ester and water. Under the appropriate conditions, inorganic acids can react with alcohol to form esters.
To generate a tiny ester, such as ethyl ethanoate, gradually boil ethanoic acid with ethanol in the presence of strong sulphuric acid, then distill the ester as soon as it develops. This prevents the opposite effect from taking place.
Esterification, a reaction in which a carboxylic acid and an alcohol are heated in the presence of a mineral acid catalyst to produce an ester and water, can be used to produce the following esters: The reaction is reversible. As an example of an esterification reaction, butyl acetate is produced from acetic acid and 1-butanol.
Frequently Asked Questions – FAQs
Q.1 What are alcohols in organic chemistry?
Alcohols are a class of chemicals with one or more hydroxyl (-OH) groups covalently linked to a single alkane. -OH is the general formula used to describe alcohols. In organic chemistry, alcohols are helpful because they can be transformed into or out of a number of different molecules.
Q.2 Is 1 Pentanol a primary alcohol?
1-Pentanol, commonly known as butyl carbinol or 1-pentyl alcohol, is an organic molecule belonging to the alcohol family. The typical structure of primary alcohols is RCOH, and they contain the primary alcohol functional group.
Q.3 What is the esterification order?
Alcohols undergo esterification in the following sequence: 1>2>3.
As steric hindrance (or bulkiness) grows from primary to secondary to tertiary alcohol, the order of esterification decreases.
Q.4 Are carboxylic acids Electrophiles?
Most nucleophiles avoid carboxylic acids as they are not particularly electrophilic. In contrast, acid chlorides are extremely aggressive electrophiles that rapidly react with weak nucleophiles like water or alcohols.
Q.5 Can two alcohols react?
Under the correct conditions, it is feasible for two alcohol molecules to dehydrate one other. The hydrogen atom of the OH group of one molecule is removed, while simply the hydrogen atom of the OH group of the second molecule is removed. A molecule of ether consists of two ethyl groups bonded to an oxygen atom.
Q.6 Do secondary alcohols react with sodium?
The reaction between ethanol and sodium metal (a base) produces sodium ethoxide and hydrogen gas. This reaction is identical to the interaction between sodium metal and water. Potassium metal experiences similar chemical reactions. The acidity of alcohol decreases from primary to secondary to tertiary fermentation.
