2-Propanol to 1-Propanol | Secondary Alcohol to Primary Alcohol

2-propanol is a primary alcohol and 1-propanol is a primary alcohol. We can convert secondary alcohol to primary alcohol in several steps. 2-propanol and 1-propanol are isomers of each other.

1-propanol is also known as propan-1-ol, 1-propyl alcohol, n-propyl alcohol, and n-propanol.

Steps of 2-propanol to 1-propanol

  1. Dehydration of 2-propanol to propene
  2. Propene and HBr reaction in the presence of organic peroxide
  3. Alkyl halide and dilute NaOH reaction

Dehydration of 2-propanol to propene

2-Propanol can be dehydrated by dehydrators such as concentrated sulfuric acid or alumina or diphosphorous pentoxide. When propanol is heated with one of these dehydrator, propene (an alkene) is given as the product.

Propene and HBr reaction in the presence of organic peroxide

When propene reacts with HBr in the presence of organic peroxide, HBr molecule is added across the double bond according to the anti-Markovnikov rule. As the product, 1-bromopropane (an alkyl halide) is given.

1-bromopropane and dilute NaOH rection

With dilute NaOH, bromine atom is replaced by hydroxyl group of NaOH and 1-propanol is given as the product.

2-propanol to 1-propanol

Written by: Heshan Nipuna

Published date: 2019-12-13

Last modified: 2013-12-13

Questions asked by students

In a paper there was a question asking how to prepare 1-propanol by 2-propanol. After a student prepare 1-propanol by 2-propanol, another student is advised to identify 1-propanol and 2-propanol by a separation method. Can you give a method to identify?

You know primary alcohols and secondory alcohols answer in different way to Lucas' reagent (anhydrous ZnCl2 / concentrated HCl).

With Lucas' reagent, 2-propanol (secondary alcohol) gives a turbidity around five minutes. But, 1-propanol (primary alcohol) does not a turbity with Lucas' reagent. So, according tothe time this turditity is given, 1-propanol and 2-propanol can be identified.

Cannot prepare 1-propanol by the reaction of propene and dilute H2SO4 reaction?

You cannot prepare 1-propanol from alkene hydration reaction because propene hydration gives 1-propanol again.

Can I prepare always primary alcohol from secondary alcohol like this?

No, you cannot always prepare primary alcohol from this way of reactions. In this method, a bromine atom is connected to the a carbon atom which is located at the end of the chain. If this possibility is there in that secondary alcohol, a primary alcohol can be prepared.

Is 2-propanol a secondary alcohol?

Around carbinol carbon atom, there are two methyl groups. Therefore 2-propanol is a secondary alcohol.

propan-2-ol to propene

Propan-2-ol and 2-propanol both are same compound and those two names are two different ways to write IUPAC name for that compound.

To prepare propene by propan-2-ol, concentrated H2SO4 acid is heated with propan-2-ol .

Are these IUPAC names correct, 2 propanol and 1 propanol ?

You have to put a dash sign after a number in the IUPAC nomenclature. So correct names should be, 2-propanol to 1-propanol.

Will propan-2-ol and propan-1-ol give propene when they are hydrated?

Both propan-2-ol and propan-1-ol give propene with dehydrators.

how can you prepare propene from propyl alcohol?

You can dehydrate propyl alcohol to prepare propene.

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