Surfactants: soaps and detergents - Introduction

There are so many applications for surfactants that anybody handles them in the daily life: in the bathroom, the kitchen, the laundry etc. They enter foam both and shower gels, shampoos, soaps, cosmetics, washing-up liquids, detergents, fabric softeners, etc. As for industry surfactants display a we alth of usages: industrial detergents, that cover many areas such as the cl eaning of facilities, machines, vehicles, even the degreasing of fabrics, O ne can find them in almost oil existing formulations, points, asphalts, lub ricants, liquid explosives, flotation agents, etc. In 2000, 11 million metric tons of surfactants were sold in the world. Euro pe and North America totalling 3 million metric tons each. Their main outle t are the household detergents (60% in Europe, 50% in North America). Perso nal core and technical applications represent respectively about 10% and 30 % in both continents. For detergents, soaps have been displaced by syntheti c or hemisynthetic molecules in developed countries, The movement started i n the early years of the 20th century. The raw materials originate in oil c hemistry (benzene, ethylene, propylene) for the former in tropical vegetabl e oils, coprah, palmiste, after fractionating (to obtain the louric/myristi c cut) for the later Some animal fats enter, in a less extend, in cationics (softeners, technical applications). The lauric/myristic cut is largely operated thanks to technical (foaming po wer, Kraft point) and price benefits. Vegetable oils of European origin (C 18 fatty chains) have shown their ability to enter household detergents in the post. The only component of Castile soap were olive oil and caustic sod a. By the way, rapeseed and linseed soaps are effective too. If at first si ght C 18 chains are not the best suited chains for modem detergents, the po ssibility to improve them is admitted by the main surfactant producers, sim ply by modifying the polar moiety of the surfactant, the hydrophilic part. For instance and as a general rule, one unit of ethylene oxide is enough to decrease the Kraft point by 10 degreesC. Therefore, rapeseed and sunflower oils could enter surfactants manufacturin g as raw materials. And that is the aim of this special issue to focus on t he most promising opportunities.