Detergents and cleaners are substances that can remove grease and dirt particles from objects and various surfaces.
The first substance marketed as a detergent was soap, which has been around for hundreds of years.
Today, with the advancement of human knowledge and technology, detergents have a high cleaning power. Moreover, considering the different structures of contaminants and their variety in various environments, specialized detergents must be used.
Cleaning surfaces without detergents does not yield satisfactory results. Below is a summary of the history of detergents and their chemical compositions.
History of Detergents
The use of natural soaps has been common among people since ancient times, and today, due to the COVID-19 pandemic and increased awareness of the effectiveness of soap in eliminating microorganisms, its usage has become even more widespread.
In the 19th century, the first soap manufacturing factory started its operations, and simultaneously, various advertising campaigns across Europe and America aimed to raise public awareness about the relationship between hygiene and health.
Before the Industrial Revolution, soap manufacturers produced soap on a limited scale. In 1789, Andrew Pears began producing transparent, high-quality soaps in London. Similarly, in 1862, he established a soap factory in Isleworth.
On the other hand, in 1850, William Gossage founded a soap factory. These factories were among the first to produce soap on an industrial scale. Initially, soaps were produced in solid form, but today, liquid forms with high viscosity are very common. Soap solutions dissolve dirt and form a suspension.
Historians, by studying ancient Egyptian artifacts, found that the most preferred method for cleaning clothes was trampling them in a basin of water. In ancient Rome, washing clothes by foot became a source of income for some people, who cleaned clothes by trampling, beating, and scrubbing them.
At that time, it was understood that various methods could enhance the cleaning power of water. For example, they realized that rainwater had a greater cleaning power than regular water and that hot water was more effective than cold water for washing.
The Egyptians used sodium carbonate, or soda ash, to increase cleaning power. Later, sodium silicate was used to soften water. These two substances formed the basis of early detergents, introduced in 1878 by a German company called Henkel’s Bleichsoda.
From the past to the present, with the advancement of human knowledge, detergents have undergone significant changes.
Chemical Composition of Detergents
Detergents are composed of surfactants that remove dirt and grime. Most detergents contain 5% active surfactants, water, and preservatives. These compounds enhance the cleanliness of clothes.
Detergent manufacturers modify the concentration of raw materials to produce stronger and more effective products for stain and dirt removal.
Here are some commonly used chemicals in detergents to familiarize you with the chemicals present in them:
Chemical Composition of Soap
In chemistry, soap is a salt of a fatty acid. Sodium or potassium salts of a fatty acid, when dissolved in water, increase cleaning properties and remove dirt.
Soap is produced by the alkaline hydrolysis of fats with natural oils such as olive oil, palm oil, coconut oil, and tallow. The process is as follows:
C3H5(OOCR)3 + 3NaOH → 3NaOOCR + C3H5(OH)3
Adding other compounds such as glycerin, sorbitol, and coconut oil to soap increases its transparency. Tetrasodium EDTA in soap enhances its softening properties and preserves its color and fragrance.
EDTA (Ethylenediaminetetraacetic acid) is a widely used substance in the detergent industry that improves washing quality.
The difference in the strength and type of intermolecular forces leads to the difference between solid and liquid soap. In solid soap, sodium ions have a smaller radius, creating stronger ionic bonds compared to potassium ions. This results in different physical states of the soap.
Chemical Composition of Dishwashing Liquid
Linear alkyl benzene (LAB) and sulfonic acid are common chemicals in dishwashing liquids with high biodegradability and environmental compatibility.
Diethanolamide or triethanolamine neutralizes acids, increases foam production, and prevents skin allergies and sensitivities.
Sodium lauryl ether sulfate (SLS), known commercially as Texapon, is one of the strongest degreasers.
Glycerin is used in dishwashing liquid formulations to make the detergent more compatible with the skin.
Many people consider the foaming capability of dishwashing liquid a sign of quality. Therefore, manufacturers use compounds such as alkanolamides, betaines, and amine oxides. However, the amount of foam produced is not an indicator of higher cleaning power. Residues of these substances may not be fully removed during washing, potentially posing long-term health risks.
Formalin is another additive used to prevent the dishwashing liquid from spoiling. The concentration of this compound should not exceed 0.3% to avoid skin damage and allergies.
Chemical Composition of Shampoo
Shampoo is one of the most commonly used detergents, with its main formula consisting of water, surface-modifying agents, and additives. Other compounds are used to improve the scent and color of the shampoo, enhance foaming, and increase viscosity. Seventy percent of the shampoo’s volume is water, and the quality of this water directly affects the quality of the shampoo.
Shampoos are responsible for washing and cleaning hair, so surfactants are used as their main ingredient.
Surfactants have a hydrophobic (water-repelling) end and a hydrophilic (water-attracting) end. The hydrophobic end attaches to fats, while the hydrophilic end attaches to water molecules, helping to separate fats from surfaces.
Surfactants are categorized as follows:
– Anionic
– Cationic
– Amphoteric
– Nonionic
Sodium lauryl ether sulfate (SLS) and disodium laureth sulfosuccinate (DLS) are anionic surfactants that make shampoos compatible with the scalp and provide high cleaning power.
Amphoteric surfactants include cocamidopropyl betaine (CAPB), which offers mild cleaning and reduces skin irritation.
Other amphoteric surfactants include coconut fatty acid diethanolamide, polysorbate 20, and polyethylene glycol 150 distearate, which regulate the pH of acidic shampoos.
Citric acid is used in anti-dandruff shampoos.
Chemical Composition of Hand Washing Powder and Machine Washing Powder
Maintaining the quality of fabrics during washing is crucial. Therefore, the formulation of washing powders includes surfactants that do not damage the fabric structure.
Dimethyl distearyl ammonium chloride is a cationic surfactant with antistatic properties.
Amphoteric surfactants in these detergents include derivatives of polyoxyethylene, polyoxypropylene, and alkanolamides.
Machine washing powders have higher cleaning power than hand washing powders due to the presence of perborate in these powders.
Trisodium phosphate is used to neutralize water hardness ions such as magnesium and calcium. This compound weakens the bond between dirt and fabric, aiding in stain removal by the powders.
One of the most commonly used compounds in washing powders is tetraacetylethylenediamine (TAED), which provides stain removal and whitening at low temperatures.
Chemical Composition of Bleach (Whitex)
Bleach is used in industry for disinfection, decolorization, and deodorization. This toxic solution contains sodium hypochlorite, which is formed by the reaction of sodium hydroxide and chlorine gas in water.
Chemical Composition of Descalers
These detergents are used for cleaning metal surfaces. Hydrochloric acid-based descalers are among the most common, known as diacids.
Chemical Composition of Degreasers
This category of alkaline detergents is used for removing oil, grease, and wax. These products are often based on sodium hydroxide or potassium hydroxide, which react with fats and hydrolyze them. One of the most widely used alkaline cleaners is ammonia, which can remove various types of oils and fats. These detergents also contain phosphate and silicate-based additives. Hydrochloric acid and phosphoric acid are acidic compounds used for degreasing in these detergents.
Chemical Composition of Surface Cleaners
Today, a variety of detergents with specific formulations are used to clean surfaces. For example, acidic solutions are used for cleaning ceramic and tile surfaces. Alkaline solutions are used to remove stains from marble, lime, and granite because these stones are sensitive to acids. Isopropyl alcohol is a component of surface cleaners for oily and greasy surfaces.
Summary of Reasons for Using Chemical Ingredients in Detergents
Various common chemical ingredients are used in detergents, each serving a specific function. These ingredients and their roles are as follows:
1. Abrasives: Used for scrubbing and polishing surfaces in cleaning products.
2. pH Adjusters and Stabilizers: Added to maintain pH balance and stabilize other components in detergents.
3. Sodium Phosphates: Compounds like trisodium orthophosphate, monosodium orthophosphate, and tripolyphosphate are used to soften water. In some regions, due to environmental concerns, chelating agents are used as substitutes for phosphate derivatives.
4. Oxidizing Agents: Utilized for whitening surfaces. In North America, sodium hypochlorite-based oxidizers are common, while in Europe, peroxide-based agents are used.
5. Fillers: Modify the physical properties of detergents. For example, sodium sulfate (borax) is added to solid detergents to ensure free flow of powders, and alcohols are used in liquid detergents to increase solubility and reduce the melting point.
6. Enzymes: Employed to remove biological stains. Enzymes are typically produced from bacteria such as *Bacillus licheniformis* or *Bacillus subtilis*.
7. Other Additives: Colors, fragrances, and foaming agents are added to provide softening, brightening, and pleasant sensory properties.
8. Glass Cleaners: Contain ammonia for cleaning and chromic acid solutions to enhance the transparency of glass surfaces.