Laureth-5

Alcohols, C12-16, ethoxylated

A derivative of lauryl alcohol with the INCI name Laureth-5 is an excellent component for many industrial applications. Although the substance is mostly used as a detergent (in washing, cleaning and laundry preparations), it is also an ingredient of cosmetic formulations and participates in processes in the textile industry. Due to a number of its advantages, Laureth-5 is readily chosen by formulators in industrial branches.

Laureth-5 – general characteristics

Laureth-5 is a surfactant that is an ethoxylated derivative of lauryl alcohol with the CAS number 68551-12-2. You can also find this compound by its common chemical names such as: ethoxylated lauryl alcohol, polyoxyethylene lauryl alcohol or polyethylene glycol lauryl ether.

As the pure compound, Laureth-5 is a liquid (at the temperature of 20 to 25ᵒC) with a faint yet characteristics odour. Its colour is often stated using what is known as the Hazen scale, which is a visual method for assessing the colouration of samples e.g. oils or crude oil derivatives (the assessment is made by comparison to the scale of platinum-cobalt standards, whose colour varies from transparent and colourless – value 0 – to yellow – value 500).  On the basis of this system, the colour of Laureth-5 is maximum 50 (at the temperature of 40ᵒC). Its molar mass is approx. 415 g/mol. The pH of a 5% aqueous solution of this substance ranges from 5.0 to 7.0 (slightly acidic to alkaline).  Laureth-5 relatively poorly dissolves in water due to its moderate hydrophilic nature. It forms clouded solutions. It achieves a much better solubility in the presence of low aliphatic alcohols such as methanol or ethanol. Laureth-5 has a density close to the one of water – at the temperature of 25ᵒC it is 0.96 g/ml.

Industrial application of Laureth-5

Laureth-5 is readily used as a non-ionic surfactant in a number of industrial applications. The main uses are as follows:

• The substance is an excellent detergent due to its strong detergency properties. Laureth-5 features a capacity to remove impurities from the surface of solids. As there are hydrophilic and hydrophobic groups in a molecule of Laureth-5, it will easily accumulate at the interphase boundary, e.g. liquid/solid boundary, where it will ensure better wetting of the surface and removal and dispersion of dirt particles. To boost the washing effect, detergent compositions are often produced by combining several ingredients, the same applies to Laureth-5. It is usually included in compositions along other non-ionic, anionic or cationic surfactants.
• The cosmetic industry uses Laureth-5 mainly as an ingredient in shampoos and shower gels. The substance has very good washing properties. Moreover, it is an emulsifier, i.e. it makes it possible to combine two immiscible phases: water and oil. The molecules of the emulsifier position themselves at the interphase boundary and dissolve partially in either phase, enabling the phases to combine. This results in another feature of Laureth-5, i.e. its capability to stabilise emulsions. This prevents a lotion or another cosmetic from breaking and losing their functional properties.
• Laureth-5 is an ingredient that is used in fibre pre-treatment processes as a component of formulations for removing oil stains (mainly from mineral oils) from woven/knitted fabrics that result from industrial knitting/weaving processes. In textile dyeing processes, Laureth-5 removes excess dyes from baths.

Advantages of Laureth-5

The physical and chemical properties of Laureth-5 determine a range of industrial applications for this substance. Its advantages make it highly popular among manufacturers in different industries.

The liquid form of the product facilitates its storage and many processing operations. Moreover, Laureth-5 features a fair resistance to hard water as well as oxidising and reducing media. The resistance to hard water, i.e. water containing high amounts of calcium and magnesium ions is particularly important, as it often eliminates the need to carry out further water treatment steps. Importantly, Laureth-5 is active even in cold water. It does not lose its properties in acidic and neutral baths or in diluted alkalis. Products such as ROKAnol® L5A (the trade name of Laureth-5 in the product range offered by the PCC Group) comply perfectly with the principles of green chemistry, because they end up in wastewater after use as ingredients of a number of detergents, and subsequently are released – finally – into the natural environment, where they undergo biodegradation.