Soaps and detergents are both cleaning products that help clean or remove
dirt, germs, and other unwanted particles from the human body and other
surfaces. Because both are used for cleaning purposes, people often get
confused between these two cleaners and use these terms interchangeably.
However, in reality, there are significant differences between soaps and
detergents.
Before discussing the difference between soap and detergent, let’s have a
quick overview of both:
What is Soap?
Soaps are prepared by the reaction of alkali (i.e., sodium hydroxide) with
naturally occurring fatty acids. This reaction helps to produce sodium salts
of the fatty acids used, which ultimately makes cleaning more efficient by
allowing water to remove greasy stains from surfaces. The soap's primary
ingredients are natural, such as vegetable oils and animal fats. However,
major-branded soaps may contain additional chemicals for particular colors and
fragrances.
The first and most common process of soap production is the saponification of
oils and fats. The second method involves neutralizing fatty acids with
alkali. Since soaps are natural, they can also be made at home using clean
glycerine, essential oils, herbs, and some spices, etc. In addition, soaps are
biodegradable due to natural ingredients. This means they are comparatively
less harmful to the environment than traditional synthetic cleansing products.
Characteristics of Soap
The following are the main characteristics of Soap:
• Soap is defined as potassium or sodium salts of carboxylic acids,
which are accompanied by a long aliphatic chain.
• Soaps are generally called surfactants; this means that they can help
reduce the surface tension between the liquid and other substances. It is
beneficial in the process of emulsification of various oils in water.
• Soap is mainly produced using the saponification process between fats
and oils.
• The two ends of the soap molecule, the carboxylate end, and the
hydrocarbon end, are hydrophilic and hydrophobic.
What is Detergent?
A detergent is usually defined as a surfactant or the combination of multiple
surfactants having cleaning properties in a dilute solution with water. Like
soaps, detergents are also called amphiphilic, which means that they also
contain hydrophobic and hydrophilic regions. In most cases, detergents are
akylbenzenefulfonates. Detergents tend to easily get dissolved in hard water
because detergents sulfonate does not attach to calcium and other ions in hard
water.
Typically, detergents are produced by mixing different chemical compounds;
then by heating the mixture and following certain measures, the powder is
dried in detergent form. The produced detergents can then be used for several
years. The chemical compounds used in the production of detergents usually
include from Dioxide, Phosphates, and Surfactants (commonly used by mainstream
detergent manufacturers) to Salt and Citric Acid. To produce detergent in
liquid form, the mixture contains a high amount of water.
Characteristics of Detergent
The following are the main characteristics of Detergent:
• Detergents are defined as potassium or sodium salts of a long alkyl
chain with a sulfonate group at the end.
• Detergents are known for their easy soluble property in hard water.
• The sulfonate group present in the detergent does not attach itself
to hard water ions, making it soluble in hard water.
• Anionic detergents like alkyl benzene sulfonates are commonly used
for domestic purposes.
Soap vs Detergent: Key Differences
Let’s discuss some major differences between soaps and detergents:
• When it comes to production, soaps are prepared using natural
ingredients while detergents are synthetic, man-made derivatives.
• The molecule of soap is usually a carboxylate ion while common
detergents often consist of phosphate or sulfate head-groups (sodium dodecyl
sulfate).
• Soaps do not easily dissolve in hard water. Detergents, on the other
hand, dissolve easily in hard water.
• Soap allows cleaning for limited applications, while detergents can
be produced according to a variety of cleaning applications.
• Soap has a weak cleansing action, while detergents have a better and
stronger cleansing action.
• The head-group of the soap molecule is a typical carboxylate anion.
However, common detergents often use phosphate or sulfate head-groups (e.g.,
sodium dodecyl sulfate).
Difference Between Soap and Detergent
Let’s discuss the difference between soap and detergent with the help of the
following comparison chart:
| Soap | Detergent |
|---|---|
| Soap is sodium or potassium of a carboxylic acid that is attached to a long aliphatic chain. | Detergent is usually a sodium or potassium salts of a long alkyl chain that terminates with a sulfonate group. |
| Soaps are produced using natural ingredients, such as vegetable oils and animal fats. | Detergents are produced using synthetic resources, such as hydrocarbons of coal or petroleum. |
| Since soaps are prepared using natural ingredients, they are easily biodegradable. | Some detergents are biodegradable. Detergents containing branched hydrocarbon chains are not easily biodegradable. |
| Soaps usually take time to get dissolved in water. | Detergents take less time and dissolve faster in water. |
| Soaps do not dissolve in hard water and saline water. That is why soaps are not effective in hard water. | Detergents tend to get dissolved in both soft water and hard water. This makes detergents effective in both types of water. |
| Soaps typically form scum when used in a hard water environment. | Detergents include compounds that do not form scum issue in any type of water. |
| Soaps are not much reactive and have weak cleansing action. | Detergents are more reactive and have strong cleansing action. |
| Soap is said to be environmentally friendly. | Detergents are compounds that can form thick foam that causes the death of aquatic life. |
| Soap can sometimes cause skin irritation. | Detergents do not usually cause skin irritation. |
| Soaps are used for limited cleaning applications, such as body parts. | Detergents are used for a variety of cleaning applications, such as laundry, dishwashing, and other types of surface cleaning. |
| Some of the most common examples of soap include sodium stearate, sodium palmitate, and sodium oleate. | Some of the most common examples of detergents include deoxycholic acid and sodium lauryl sulfate. |
How does a cleaning process for soaps and detergents work?
The concept of a cleaning process is almost the same for both soaps and
detergents. We can explain step by step process of cleaning using the
following four points:
• First, the surface or a body that needs to be cleaned is moistened
using water.
• Next, soap or detergent is applied to the surface that is absorbed.
Because both soaps and detergents are known as surfactants (or surface-active
agents), the surface-active molecules that exist in soaps and detergents
dissolve in water. This ultimately helps to weaken the surface tension, the
applied force, that attaches molecules to a surface. As a result, water is
easily spread on a surface or soaked in a cloth.
• When the surface is rubbed, dirt particles present on the surface
break down as surface-active molecules work to separate the dirt from the
surface and attach them to the water. The same rule works with clothes.
• At last, dirt particles are coated with molecules of soap or
detergent, preventing them from re-attaching to the surface. This eventually
causes dirt particles to be suspended in water until the dirt is completely
washed away.
Summary
Both soap and detergent are intended to help clean up, but there are
differences in their production process and quality of cleaning. While soaps
are based on natural ingredients, detergents are prepared with synthetics and
are man-made derivatives.
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