Alcohols

Edited by Jamie (ScienceAid Editor), Taylor (ScienceAid Editor), Sim

The alcohols are another homologous series of compounds that have the general formula CnH2n+1OH.

Ad

The Alcohol Series

The names of the alcohols follow the same pattern as the alkanes and the alkenes. Here are the first few, their names, chemical and structural formula:

Methanol Ethanol Propanol Butanol
CH3OH C2H5OH C3H7OH C4H9OH
methanol.png
ethanol.png
propanol.png
butanol.png

Types of Alcohol

We have three different types of alcohol depending on the structure. They will react differently, which is why you need to know the differences, but they are very simple.

comparison of primary, secondary and tertiary alcohols

The easy way to work it out is the number of carbon atoms bonded to the COH group.

  1. 1
    Primary.
    A primary alcohol has 0 or 1 carbon on the COH.
    Advertisement
    Was this step helpful? Yes | No | I need help
  2. 2
    Secondary.
    The secondary alcohol has 2 carbons.
    Was this step helpful? Yes | No | I need help
  3. 3
    Tertiary.
    The tertiary alcohols have 3 carbon atoms bonded to the C-OH. Tertiary alcohols will not oxidize easily, so regarding the reaction, you won't see much happen.
    Was this step helpful? Yes | No | I need help
    Advertisement

Manufacturing Ethanol

There are two methods of manufacturing ethanol - either from ethene or sugar.

Ethene

Producing alcohol from ethene is more common in developed countries like those in North America and Europe, where ethene is widely available. The following reaction between ethene and steam takes place with a phosphoric acid catalyst at 600°C and high pressure.

Was this helpful? Yes | No | I need help
reaction between ethene and steam to produce ethanol

Sugar

The production of ethanol using sugar is more common in developing nations with less oil and ethene but a lot of agricultural produce. This method also makes use of material that would have otherwise gone to waste. Plant material is fermented for several days, and the following reaction takes place:

Was this helpful? Yes | No | I need help
Glucose ==>> Ethanol + Carbon Dioxide
C6H12O6(aq) ==>> 2C2H5OH(aq) + 2CO2(g)

The ethanol produced is combustible, so can be used in car engines. This has become known as biofuel. Initially, it was believed to provide a more environmentally friendly source of fuel to replace fossil fuels. It appears, however, to do more harm than good by reducing the supply of food and encouraging deforestation to plant crops that can be fermented.

Was this helpful? Yes | No | I need help

Uses of Ethanol

Ethanol is by far the most commonly used alcohol, including the alcohol in your cocktails. It has numerous applications, including:

  • As a solvent for paints and perfumes. When the product is applied, the ethanol evaporates.
  • It is used as fuel. Most notably in Brazil, where either pure ethanol or a mix with petrol (gas) is used to fuel the majority of cars. This can be a carbon neutral way to fuel transport, because although carbon dioxide is produced in combustion, manufacturing it by fermentation means all CO2 is absorbed by growing the plants to ferment.
Was this helpful? Yes | No | I need help

For making other compounds like ethanoic acid (see below) or esters.

Oxidation

Alcohols can be oxidized by using chemicals like acidified potassium dichromate in warm conditions. The products vary depending on the type of alcohol. For example - a primary alcohol will oxidize to to an aldehyde and given further oxidation it will become a carboxylic acid. Have a look at the examples below using ethanol.

Was this helpful? Yes | No | I need help

oxidation of primary alcohols

The [O] is notation used to represent oxidation. Ethanol first becomes the aldehyde ethanal and produces water. With further oxidation (step 2) this is oxidized to ethanoic acid.

A secondary alcohol can will be oxidized to a ketone with the functional group CO. The diagram below shows what the ketone propanone looks like.

diagram of propanone

Ethanoic Acid

Formerly known as acetic acid, ethanoic acid a type of carboxylic acid with the molecular formula of C2H4O2 and structural formula of:

structural formula of ethanoic acid

It is the acid found in vinegar, which is why if wine is left, the ethanol in it oxidizes to become ethanoic acid:

Ethanol + Oxygen ==>> Ethanoic Acid + Water
C2H5OH + O2 ==>> CH3COOH + H2O

Questions and Answers

Yes sir, List three uses of trioxonitrate acid and alcohol?

List three uses of trioxonitrate acid and alcohol in details

The process where trioxonitrate (or nitric acid) reacts with alcohol is called nital. This process is mainly used for etching of metals and showing the microstructure of carbon steels.

Referencing this Article

If you need to reference this article in your work, you can copy-paste the following depending on your required format:

APA (American Psychological Association)
Alcohols. (2017). In ScienceAid. Retrieved Mar 25, 2017, from https://scienceaid.net/chemistry/organic/alcohols.html

MLA (Modern Language Association) "Alcohols." ScienceAid, scienceaid.net/chemistry/organic/alcohols.html Accessed 25 Mar 2017.

Chicago / Turabian ScienceAid.net. "Alcohols." Accessed Mar 25, 2017. https://scienceaid.net/chemistry/organic/alcohols.html.

If you have problems with any of the steps in this article, please ask a question for more help, or post in the comments section below.

Comments

ScienceAid welcomes all comments. If you do not want to be anonymous, register or log in. It is free.

Ask the author

Jamie
Featured Author
166 Articles Started
1,274 Article Edits
43,215 Points
Jamie is a featured author with ScienceAid. Jamie has achieved the level of "Captain" with 43,215 points. Jamie has started 166 articles (including this one) and has also made 1,274 article edits. 71,200 people have read Jamie's article contributions.
Jamie's Message Board
Jamie: Hi, my name is Jamie.
Jamie: Can I help you with your problem about "Alcohols"?
 

Article Info

Categories : Organic

Recent edits by: Taylor (ScienceAid Editor), Jamie (ScienceAid Editor)

Share this Article:

Thanks to all authors for creating a page that has been read 1,195 times.

Do you have a question not answered in this article?
Click here to ask one of the writers of this article
x

Thank Our Volunteer Authors.

Would you like to give back to the community by fixing a spelling mistake? Yes | No