Primary alcohols
Primary alcohols are oxidation and Grignard-route products in the expanded aliphatic pathway map.
- Functional group
- RCH2OH
- Also known as
- primary alcohol
Overview
Alcohols where the carbon bearing OH is attached to one carbon group.
Primary alcohols are oxidation and Grignard-route products in the expanded aliphatic pathway map.
A primary alcohol normally has a -CH2OH group. Controlled oxidation gives an aldehyde; further oxidation gives a carboxylic acid. Removing the aldehyde as it forms can limit further reaction. Methanol is the usual structural exception to the carbon-substituent counting rule.
Identifiers
- Functional group
- RCH2OH
- Also known as
- primary alcohol
Chemical identifiers
- SMILES
- CCO
Properties
- Classification
- Count carbon groups on the OH-bearing carbon, not the total number of carbons in the molecule.
- Oxidation outcome
- Oxidant, water content and product removal determine whether the aldehyde survives.
Diagnostic tests
acidified dichromate oxidation test
- Reagent
- acidified K2Cr2O7(aq)
- Conditions
- Add aqueous potassium dichromate(VI), acidified with dilute sulfuric acid, to the sample and warm gently in a water bath.
- Positive observation
- the orange solution turns green
- Negative observation
- the solution remains orange
- Interpretation
- A positive result is consistent with a primary alcohol being oxidised to an aldehyde and, under stronger conditions, a carboxylic acid.
- Scope
- Primary alcohols give this oxidation colour change.
- Limitations
- Primary alcohols, secondary alcohols and aldehydes can give this response.
- Evidence
- textbook core
Related compounds
- Propan-1-ol
A primary alcohol linking hydrogen bonding, aldehyde formation and further oxidation.
- Butan-1-ol
Butan-1-ol is an organic compound with the molecular formula C4H10O.
- 2-Methylpropan-1-ol
A branched primary alcohol whose oxidation retains the carbon skeleton.
- Pentan-1-ol
Pentan-1-ol is an organic compound with the molecular formula C5H12O.
- Hexan-1-ol
Hexan-1-ol is an organic compound with the molecular formula C6H14O.
- Octan-1-ol
Octan-1-ol is an organic compound with the molecular formula C8H18O.
- Benzyl alcohol
A primary alcohol whose CH2OH group is attached to a phenyl ring.
- 2-Phenylethanol
2-Phenylethanol is an organic compound with the molecular formula C8H10O.
- Glycolic acid
Glycolic acid is an organic compound with the molecular formula C2H4O3.
Connected reactions
- Controlled oxidation: Primary alcohols → Aldehydes
Controlled oxidation of a primary alcohol gives an aldehyde.
- Complete oxidation: Primary alcohols → Carboxylic acids
Full oxidation of a primary alcohol gives a carboxylic acid.
- Reduction: Aldehydes → Primary alcohols
Reduction of an aldehyde gives a primary alcohol.
- Reduction: Carboxylic acids → Primary alcohols
Reduction of a carboxylic acid gives a primary alcohol.
- Carbonyl addition: Grignard reagents → Primary alcohols
Grignard addition to methanal gives primary alcohols after work-up.
- Grignard addition co reactant: Methanal → Primary alcohols
Methanal plus a Grignard reagent gives a primary alcohol after acidic work-up.
References
- Organic Chemistry: Oxidation of AlcoholsJohn McMurry · OpenStax Organic Chemistry · 2023
Supports functional-group chemistry used to curate the linked examples. Checked 2026-09-16; named examples are applications of textbook scope, without claimed experimental yields.
- Pearson Edexcel International Advanced Level Chemistry Practical GuidePearson Education Limited · Pearson qualifications · 2018
Official Pearson practical guidance for organic qualitative tests, including bromine water, acidified dichromate, silver nitrate, carbonyl reagents and the iodoform reaction.
- PubChem Compound Summary: Propan-1-ol (CID 1031)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Butan-1-ol (CID 263)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: 2-Methylpropan-1-ol (CID 6560)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Pentan-1-ol (CID 6276)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Hexan-1-ol (CID 8103)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Octan-1-ol (CID 957)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Benzyl alcohol (CID 244)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: 2-Phenylethanol (CID 6054)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Glycolic acid (CID 757)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.