In recent years there has been a significant growth in the manufacturing capacity for oleochemical-based surfactant alcohols, partly due to the impact of oil prices on petrochemicals, but also because of a perception that these products enhance the environmental profile of laundry detergents. Oleochemical alcohols are derived from vegetable oils, such as palm, palm kernel or coconut oil.
Changing economic factors, a more informed debate over the attributes of oleochemical alcohols and concerns over the methods employed to produce them, however, have slowed and in some cases halted the growth.
"We've seen a gradual change in the perception that oleo products, due to their plant or vegetable origins, are more natural, and hence more environmentally acceptable," says Rob van der Meij (right), Global Business Manager, Alcohol and Alcohol Derivatives.
Chemically processed
"In reality all alcohols are synthetic. Although the starting material for oleochemical alcohols is a renewable source, the final product is highly chemically processed, and there is no inherent difference in terms of their environmental performance." He says that studies by leading detergent formulators have confirmed this view.
Thomas Mueller-Kirschbaum, Head of R&D/Technology/Supply Chain for the Laundry and Home Care division of Henkel says: "We select raw materials carefully based on their environmental and eco-toxicological profile, and both types of alcohol feedstocks show comparable and acceptable performance."
Life-cycle analysis by leading 'soapers' has shown that the origin of the surfactant is not a significant factor in environmental performance - and that molecular structure and solubility determine an alcohol's bio-degradability and toxicity.
"In this respect the two alcohol types are very similar," says van der Meij.
"Both have low toxicity and bio-degrade equally well. Harmonisation of product labelling and classification means that no distinction is made on product packaging."
Charles Bragg, Procter and Gamble's Director of R&D - Fabric Care and Laundry Formulations, says: "We have done a lot of analysis work in this area and have found no measurable difference in environmental performance. As a result we think it's important to be flexible enough to use both types of alcohols."
Barbara De-Kort, Director of R&D for Unilever's global portfolio of laundry detergent products, adds: "From an environmental aspect the surfactant feedstock is not the big issue. There is no clear cut case for using only oleo-based surfactants and it's not something that is driving consumer choice."
While the consumer is the main driving force in formulation development, cost control and security of supply are still major factors for raw material selection. "This is a value driven business, where the cost/performance ratio of surfactant systems is a key element," says Mueller-Kirschbaum.
Balanced market
Retreating crude prices and changing economics in the oleochemicals market have played a significant part in the balancing of surfactant alcohols consumption. While oil prices have come down, the price of oleochemicals has been impacted by increased demand for palm and vegetable oils for use in bio-fuels.
At the same time the value of plant oil byproducts such as glycerine has fallen.
If the oil price is volatile, the supply of plant oils is equally uncertain. Harvests are reliant on climate, while the availability of agricultural land is under pressure due to the need for increased food production.
Plant oil production itself is under environmental scrutiny. The spotlight has fallen on the high intensity farming, involving vast plantations, required to respond to the growth in demand. The voracity of palm oil harvesting, particularly in South East Asia, can lead to major deforestation with knock-on effects on wildlife habitats and the local communities.
These concerns have already prompted action by some major retailers. US retailer WalMart has embarked on a wide-ranging review of its detergent raw materials policy, while UK supermarket chain Morrisons has made a public commitment to be 'palm-oil free' by the end of 2010.
"What this shows is that the price, availability and acceptability of both surfactant feedstocks are dependent on a number of factors that are impossible to predict in our fast-changing world," says van der Meij.
As a result, the threat of a substitution trend has subsided and major detergent manufacturers continue to have both types of alcohols in their product portfolios.
"We use surfactants from various feedstocks to cost optimise products and to ensure security of supply," says Unilever's De-Kort. "Volatility in both feedstock markets has emphasised the need to develop the capability to switch from one source to another."
"Formulators are under pressure from major retailers to keep formulation costs down and so our feedstock selection is driven by price and availability as well as supply security and diversification," explains P&G's Charles Bragg."
Shell has also changed its mindset to a degree says van der Meij. "We recognise the importance of being responsive to changing market conditions. While our NEODOL* petrochemical-based alcohols will always be the mainstay of our business, we have the flexibility in our manufacturing system to source oleo alcohols for ethoxylation when supply factors dictate.
"The changing economic and environmental dynamics has led to a realisation across the industry that there are roles for both types of alcohols."
While oleo feedstocks can be processed - or ethoxylated - using the same production methods, there are technical reasons why detergent makers continue to rely on petrochemical alcohols for some formulations.
Technical advantages
Subtle but important differences in their molecular structure can play a significant part in product differentiation and development. "The wide range of consumer requirements (wash conditions) would be more difficult to meet without some of the technical and performance characteristics petrochemical alcohols can offer in certain detergent applications," says Rick Gibbs, Technology Manager for Higher Olefins and Derivatives.
"They are able to dissolve with other detergent components without compromising cleaning performance, enabling mixed surfactant formulations to be developed with specific performance or aesthetic characteristics."
Their molecular structure also gives the formulator added flexibility for developing new products. "Petrochemical alcohols can be produced in a variety of chain lengths, which can be tailored to a specific end-use," explains Gibbs. "This allows for more customised formulations, particularly in the development of more concentrated and lower temperature detergents."
Colder wash temperatures result in energy savings during the consumer use phase of the surfactant life-cycle, which has a positive environmental effect.
More concentrated, compact laundry detergents, compared to the traditional "big-box" powders, reduces packaging, transport costs and shelf space, as well as the detergent used per wash load.
"These types of innovations are becoming increasingly important drivers for the detergents industry," says van der Meij. "As a result, formulation flexibility and performance will continue to be key factors in the detergents manufacturers' selection of alcohol feedstocks."
The heads and tails of surfactants
Laundry detergents are composed of three main building blocks - surfactants, builders and buffers - and a variety of performance enhancers used to remove soil and stains from garments and keep them suspended in the wash solution.
Surfactants, which make up around 25%, are alcohol-based substances that carry dirt or soil away during the cleaning process. All surfactant alcohols have the same basic structure: a hydrophilic (water-loving) "head" and a hydrophobic (fat-loving) "tail". The tail binds to and mobilises soil particles, and the head works to pull the soil-surfactant couple to the water phase, to be flushed away with the wastewater.
While the carbon chains of oleochemical alcohols are always linear and even-numbered, petrochemical alcohols have a small amount of branching and may contain even or odd numbers of carbon atoms. This branching offers formulation flexibility and can be used to influence technical parameters including cold-water solubility, viscosity, foaming and low temperature stability.
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