Emerging Technologies for Sustainable Biobased Surfactants
Biobased surfactants are eco-friendly products that are considered to be successful substitutes for petroleum derived synthetic chemical surfactants, for most applications. This class of surfactants have gained immense importance in the field of laundry, household cleaners, pharmaceutical, personal care, coatings, lubricants, and oil field industries.
In the past few decades, biobased surfactants had captured attention because they exhibited some technical advantages such as biodegradability, low toxicity, ecological acceptability, and ability to be produced from renewable and less expensive substrates. Biobased Surfactant Classifications Biobased surfactants are surface active agents that are synthesized from either sugars or oils and fats via oleochemical production. Emphasis on sustainability, along with decarbonization, has led to companies accelerating their search for alternatives to the petroleum-based surfactants such as the ethoxylated alcohols. Defossilization of ethoxylated surfactants has been achieved with the use of ethylene oxide from bio-based ethanol vs. ethylene oxide from petroleum ethylene. Most biobased surfactant are fatty acid derivatives and can be classified as follows:
Methyl Ester Sulfonates (MES)
Alkyl Polyglucosides (APG)
Anionic APG Derivatives
Alkyl Polypentosides (APP)
Fatty Acid N-Methyl Glucamide
Methyl Glucoside Esters
Methyl Ester Sulfonates (MES) are an important and fast-growing class of anionic biobased surfactants used in a wide range of industries. They are produced by sulfonation of saturated fatty acid methyl esters. Household cleaners, including laundry applications, are the single largest use for surfactants. These surfactants utilize palm kernel oil and/or coconut oil which contain high levels of lauric acid which are used to make sodium lauryl sulfate and sodium laureth sulfate.
Microorganisms have been reported to produce several classes of biosurfactants such as glycolipids, lipopeptides, phospholipids, neutral lipids, or fatty acids and polymeric biosurfactants. These surfactants are manufactured from microbial origins and are not to be confused with biobased surfactants that are partially or 100% from biological sources. Most emerging biosurfactants fall into two categories including rhamnolipids or sophorolipids. Making these surfactants involve expertise in precision fermentation technologies with triglyceride feedstocks from palm, rapeseed, or soybean oil.
Conventional soybean oil, which is the second largest source of plant-based oil, has been limited in high use markets, due to the higher level of polyunsaturates and longer carbon chains that limit water solubility and biodegradability. Improved varieties of soybeans are about to change this.
New varieties of high oleic soybean oil, with 75% oleic acid content, are being grown in the U. S A number of organizations have utilized high oleic soybean oil to develop surfactant products in various markets. These include Colonial Chemical, Synalloy, and Battelle.
Conventional vegetable oils have multiple double bonds such as linoleic which produce side reactions. This results in undesirable by-products, leading to water insolubility and lower biodegradability. Since high oleic soybean oil possess a higher degree of unsaturation, the chemistry can produce water miscible and stable surfactants with the ability to control bio-content, functional groups (such as chelators), and ultimately vary the hydrophilic-lipophilic balance (HLB) to improve product performance.
There are many more examples of biobased surfactants as manufacturers continue to revolutionize the cleaning, personal care, and many other industries. As the race to net zero intensifies, businesses face growing pressure to publicize environmental performance and reduce greenhouse gas (GHG) emissions.