Surfactants, also known as wetting agents, lower the surface tension of a liquid, allowing easier spreading. The term surfactant is a compression of "Surface active agent". Surfactants are usually organic compounds that contain both hydrophobic and hydrophilic groups, and are thus semi-soluble in both organic and aqueous solvents. By lowering the surface tension of water, surfactants enable the cleaning solution to wet a surface (e.g., clothes, dishes, countertops) more quickly, so soil can be readily loosened and removed (usually with the aid of mechanical action). Surfactants also emulsify oily soils and keep them dispersed and suspended so they do not settle back on the surface. To accomplish their intended jobs effectively, many cleaning products include two or more surfactants. Surfactants are also known as amphipathic compounds, meaning that they would prefer to be in neither phase (water or organic). For this reason they locate at the phase boundary between the organic and water phase, or, if there is no more room there, they will congregate together and form micelles. The concentration at which surfactants begin to form micelles is known as the critical micelle concentration or CMC.
Surfactants are also known as wetting agents. They may be liquids or powders. Surfactants are used in aqueous cleaners to provide detergency, emulsification, and wetting action. Surfactants used in aqueous cleaners are usually biodegradable. The various soils and parts used in your process and the concentrations of your cleaner will affect biodegradability. Lowering the surface tension of the cleaning solution helps the solution drain from the part being cleaned. Surfactants have several roles: they modify or "wet-out" the surface being cleaned or the soil being removed, and they help form an emulsion of solvent in water for cleaning or of soil in water for flushing away.
The four major classifications of surfactants are: anionic, cationic, nonionic, and amphoteric. Anionic surfactants are water soluble and have a negative charge in aqueous solution. Cationic surfactants have a positive charge in aqueous solution and are considered to be poor cleaners. Nonionic surfactants are the most widely used for surface cleaning and have no charge in aqueous solutions. Amphoteric surfactants develop a negative or positive charge depending on whether the solution is alkaline or acidic.
Anionic surfactants are used in laundry and hand dishwashing detergents; household cleaners; and personal cleansing products. They ionize (are converted to electrically charged particles) in solution, carry a negative charge, have excellent cleaning properties and generally are high sudsing. Linear alkylbenzene sulfonate, alcohol ethoxysulfates, alkyl sulfates and soap are the most common anionic surfactants.
Nonionic surfactants are low sudsing and are typically used in laundry and automatic dishwasher detergents and rinse aids. Because they do not ionize in solution and thus have no electrical charge, they are resistant to water hardness and clean well on most soils. The most widely used are alcohol ethoxylates. Nonionic surfactants are a class of synthetic surfactants. They are prepared by attaching ethylene oxide molecules to a water-insoluble molecule. The ethylene oxide molecules, derived from petroleum, are water-soluble polymers. Depending on the number of ethylene oxides and the number of carbon atoms, the synthetic surfactants can be classified as a wetting agent, a detergent, or an emulsifier.
Cationic surfactants are used in fabric softeners and in fabric-softening laundry detergents. Other cationics are the disinfecting/sanitizing ingredient in some household cleaners. They ionize in solution and have a positive charge. Quaternary ammonium compounds are the principal cationics.
Amphoteric surfactants are used in personal cleansing and household cleaning products for their mildness, sudsing and stability. They have the ability to be anionic (negatively charged), cationic (positively charged) or nonionic (no charge) in solution, depending on the pH (acidity or alkalinity) of the water. Imidazolines and betaines are the major amphoterics.
Oleochemicals are made from vegetable and animal oils and fats and/or petrochemicals feedstocks. They range from fatty acids, glycerine, alcohols and metallic soaps to fatty nitriles and their derivatives.
The raw materials for oleochemicals come from many parts of the world both from vegetable and animal origin. A large proportion of the vegetable oils such as coconut, palm and palm kernel oil is coming from tropical countries. More temperate climates allow the harvesting and subsequent production of soybean, rape and sunflower oils. Wood or tall oil is another source of vegetable oils. It is a by-product from the paper pulp industry. Animal fat is obtained from the meat industry, beef tallow being the most abundantly available fat. The Fishing industry is the source for fish oils. The raw materials are available annually in sufficient quantities. The agricultural production of the oil seed crops delivers every year a new harvest and are therefore trully renewable. The food industry is the key driver in the oils and fats market arena.
The two major, commercially significant oleochemicals are fatty acids and glycerin, both formed by hydrolysis of fats and oils. Methanolysis yields fatty acid methyl esters and glycerin, which for the purposes of this report will be referred to as first generation oleochemicals. Other oleochemicals are fatty alcohols and fatty amines, which are both derived from the first generation products. Basic oleochemicals are fatty acids, methyl esters, fatty alcohols, fatty amines and glycerol. They are essentially the building blocks of the oleochemicals industry. From these basic oleochemicals, a very wide range of oleochemical derivatives can be produced. Since palm oil and palm kermel oil contain between them almost the entire range ot ratty acids, practically all the oleochemicals can be produced from them. By applying chemical know-how, oleochemicals feedstocks are converted into a wide range of chemical products for use in lubricants, soaps and detergents, cosmetics, pharmaceuticals, food additives, leather, paints and coatings, printing inks, rubber, plastics, metal-working and many other industries. In fact, few products have a wider range of application than oleochemicals.
For oleochemical production, the major commercial processes applied to animal and vegetable oils and fats are saponification, hydrolysis, and methanolysis, all of which lead to glycerol and mixed fatty acid fragments (i.e., first generation oleochemicals) in the acid or ester form. The resulting mix of fatty acid fragments and the quantity of glycerol recovered depends upon the specific fat or oil used in the process. A relatively small proportion of fats and oils, mainly from the sperm whale and jojoba seeds, are rich in esters of fatty acids and fatty alcohols of the structure R1-COOR2, where R1 and R2 are C14 to C18, saturated or unsaturated, acid groups. These mixed esters are waxy solids that have value in a number of specialty applications, particularly in personal care products. The triglyceride concentrations are low compared to other fats and oils, and only about 2 to 5 percent can be expected. These waxy esters can be subjected to hydrolysis to separate the fatty acid and fatty alcohol components.
Few products have a wider range of applications than oleochemicals. Indeed, this diversity of markets is an important factor in the stability of the industry.
Here are a few ways in which oleochemicals are used:
Soaps and detergents: Industrial and domestic
Health and personal care: Culture media, tabletting aids, shampoos, soaps, creams, lotions, make-up
Food: Emulsifiers and specialities for bread, cakes and pastries, margarine, ice cream and confectionery
Animal feed: Nutritional supplements, emulsifiers for calf milk replacers
Electronics: Wire insulation, insulating varnishes, special-purpose plastic components
Industrial lubricants: General and speciality lubricants, base oils for non-toxic biodegradable lubricants
Leather: Softening, dressing, polishing and treating agents
Metalworking and foundries: Cutting oils, coolants, buffing and polishing compounds
Mining: Froth flotation of ores, surface-active agents for oil-well drilling muds
Paints and coatings: Alkyd and other resins, drying oils, protective coatings
Paper re-cycling: Removal of printing ink
Plastics: Stabilisers, plasticisers, mould release agents, lubricants, anti-statics, antifogging aids, polymerisation emulsifiers
Printing: Printing inks, paper coatings, photographic printing
Rubber production: Vulcanising agents, softeners, mould release agents
Waxes: Ingredients in waxes and polishes
Oleochemicals are generally classified as non-hazardous, being non-toxic and not susceptible to spontaneous heating, in accordance with definitions set forth by existing laws and regulations. Nevertheless, normal precautions should be observed for the safe handling and storage of these chemicals.