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  1. 1. DETERGENTS Surfactants are one of the major components of cleaning products and can Detergents are composed of physical or be regarded as the 'workhorses': they do chemical active ingredients such as the basic work of breaking up soils and surfactants, builders, solvents, chelators, keeping the dirt in the water solution to preservatives, bleaches and enzymes. prevent re-deposition of the dirt onto the surface from which it has just been 1. Surfactants removed. Surfactants disperse dirt that 2. Chelating/Sequestering Agents normally does not dissolve in water. 3. Builders 4. Solvents Each surfactant molecule has a hydrophilic 5. Preservatives (water-loving) head that is attracted to 6. Bleaches water molecules and a hydrophobic (water- 7. Enzymes hating) tail that repels water and simultaneously attaches itself to oil and 1. Surfactants grease in dirt. These opposing forces loosen the dirt and suspend it in the water. The interaction between water, surfactant, and surface is called “surface activity.” In fact, the name surfactant comes from the phrase “SURFace ACTive AgeNT.” Surfactants are molecules that reduce the surface tension of water, helping it to spread out more uniformly. Basically, surfactants make water “wetter”. They also help penetrate, loosen and trap soils . In more technical terms:  Surfactants enable the cleaning solution to fully wet the surface being cleaned so that dirt can be readily loosened and removed.  Surfactants clean greasy, oily, Modern technology can produce many particulate-based, protein-based, and different types of surfactants by changing carbohydrate-based stains. the chemical composition of the hydrophobic and hydrophillic ends of the  Surfactants are instrumental in molecule. By changing the chemical removing dirt and in keeping them composition, surfactants have greater or emulsified, suspended, and dispersed lesser abilities in different areas: so they don't settle back onto the surface being cleaned. a. Detergency: the ability to break the bond between soil and the surface. Compiled by Deniz Kaya -1-
  2. 2. b. Penetrating and wetting: allows water to the surfactants surround it until it is surround soil particles that would dislodged from the boundary. Notice in otherwise repel the water. diagram 4 that the dirt molecules are actually suspended in solution. c. Foaming: creation of bubbles that lift dirt from the surface. d. Emulsifying: the ability to break up greasy petroleum soils into small droplets that can be dispersed thoroughly. e. Solubilizing: dissolving a soil so that it is no longer a solid soil particle. f. Dispersing: spreading the minute soil particles throughout the solution - to prevent them back onto the cleaned surface. Many surfactants will be used in combination to create a cleaner/detergent with just the right balance of detergency, foaming, wetting, emulsifying, solubilizing and dispersing properties. Each surfactant contributes its own special abilities to the cleaner formula. Surfactants can be natural or synthetic origin. Surfactants from natural origin (vegetable or animal) are known as oleo- chemicals and are derived from sources such as palm oil or tallow. Surfactants from synthetic origin are known as petro- chemicals and are derived from petroleum. Formulation scientists focus quite a lot on developing detergents that perform well at lower wash temperatures. This approach will continue to yield energy savings during the consumer use phase, hence a reduction of CO2 emissions. The surfactant lines up at the interface. The hydrophobic end of the molecule gets away from the water and the hydrophilic end stays next to the water. When dirt or grease is present (hydrophobic in nature) Compiled by Deniz Kaya -2-
  3. 3. The law of mass cleaning action expresses water with the positively charged water a relationship between time, action, hardness ions (calcium and magnesium) , concentration, and temperature in the which can lead to partial deactivation. The process of removing soils. This laws states more calcium and magnesium molecules in that if you decrease any one of these the water, the more the anionic surfactant factors, we must increase one or more of system suffers from deactivation. To the remaining factors in order to maintain prevent this, the anionic surfactants need equal cleaning ability. help from other ingredients such as builders (Ca/Mg sequestrants) and more detergent should be dosed in hard water. The most commonly used anionic surfactants are alkyl sulphates (AS), alkyl ethoxylate sulphates (AESs) and soaps. LAS (Linear Alkylbenzyne Sulphonate) O O CH 3 (CH 2 ) 11 S Na O LABSA (Linear Alkylbenzene Sulphonic Acid) SO3 There is a broad range of different o surfactant types, each with unique properties and characteristics. Detergents use a combination of various surfactants to provide the best possible cleaning results. There are four main types of surfactants used in cleaning products. Depending on the type of the charge of the head, a surfactant belongs to the anionic, cationic, non-ionic or amphoteric/zwitterionic family. Anionic surfactants In solution, the head is negatively charged. This is the most widely used type of surfactant for laundering, dishwashing Cationic surfactants liquids and shampoos. In solution, the head is positively charged. Anionic surfactants are particularly There are 3 different categories of effective at oily soil cleaning and oil/clay cationics each with their specific soil suspension. They can react in the wash application: Compiled by Deniz Kaya -3-
  4. 4. 1. In fabric softeners and in detergents with 3. In household and bathroom cleaners, built-in fabric softener, cationic surfactants cationic surfactants contribute to the provide softness. Their main use in laundry disinfecting/sanitizing properties. products is in rinse added fabric softeners, such as esterquats (esterified quaternary Non-ionic surfactants ammonium compounds), one of the most widely used cationic surfactants in rinse These surfactants do not have an electrical added fabric softeners. charge, which makes them resistant to water hardness deactivation. They are An example of cationic surfactants is the excellent grease removers that are used in esterquat. laundry products, household cleaners and hand dishwashing liquids. Nonionic surfactants , which do not dissociate when dissolved in water, have the broadest range of properties depending upon the ratio of hydrophilic/ hydrophobic balance. This balance is also affected by 2. In laundry detergents, cationic temperature. For example, the foaming surfactants (positive charge) improve the properties of nonionic detergents is packing of anionic surfactant molecules affected by temperature of solution. As (negative charge) at the stain/water temperature increases, the hydrophobic interface. This helps to reduce the character and solubility decreases. At the dirtl/water interfacial tension in a very cloud point (minimum solubility), these efficient way, leading to a more robust dirt surfactants generally act as defoamers, removal system. They are especially while below the cloud point they are varied efficient at removing greasy stains. in their foaming properties. An example of a cationic surfactant used in Most laundry detergents contain both non- this category is the mono alkyl quaternary ionic and anionic surfactants as they system. complement each other's cleaning action. Non-ionic surfactants contribute to making the surfactant system less hardness sensitive. The most commonly used non-ionic surfactants are ethers of fatty alcohols CTAB (Cetyl Trimethyl Ammonium Bromide) CH 3 CH 3 N Cl CH 3 (CH 2 ) 15 CH 3 Compiled by Deniz Kaya -4-
  5. 5. NPE (Nonyl Phenol (Poly)Ethoxylate) Dodecyl Dimethyl Sulphobetaine CH 3 H 2 O CH 3 (CH 2 ) 8 O(CH 2 CH 2 O) m H C N S CH 3 (CH 2 ) 11 O CH 3 O Amphoteric/zwitterionic surfactants Dodecyl Dimethyl Amine Oxide These surfactants are very mild, making CH 3 CH 3 them particularly suited for use in personal care and household cleaning products. N OH H O N They can be anionic (negatively charged), CH 3 (CH 2 )11 CH 3 CH 3 (CH 2 ) 11 CH 3 cationic (positively charged) or non-ionic (no charge) in solution, depending on the acidity or pH of the water. They behave as It is a common practice to blend surfactant cationic surfactants under acid conditions, ingredients to optimize their properties. and as anionic surfactants under alkaline However, because of precipitation conditions. problems, cationic and anionic surfactants cannot be blended. They are compatible with all other classes of surfactants and are soluble and effective 2.Chelating/Sequestering Agents in the presence of high concentrations of electrolytes, acids and alkalis. Soil removal is a complex process that is much more involved than just adding soap These surfactants may contain two charged or surfactant to water. One of the major groups of different sign. Whereas the concerns we have in dealing with cleaning positive charge is almost always compounds is water hardness. Water is ammonium, the source of the negative made "hard" by the presence of calcium, charge may vary (carboxylate, sulphate, magnesium, iron and manganese metal sulphonate). These surfactants have ions. These metal ions interfere with the excellent dermatological properties. They cleaning ability of detergents. The metal are frequently used in shampoos and other ions act like dirt and "use up" the cosmetic products, and also in hand surfactants, making them unavailable to act dishwashing liquids because of their high on the surface we want to clean. foaming properties. A chelating agent (pronounced keelating from the Greek word claw) combines itself with these disruptive metal ions in the water. The metal ions are surrounded by the claw-like chelating agent which alters the electronic charge of the metal ions from positive to negative (see diagram below.) This makes it impossible for the metal ions to be precipitated with the surfactants. Thus, chelated metal ions remain tied up in solution in a harmless Compiled by Deniz Kaya -5-
  6. 6. state where they will not use up the Precipitation - removing metal ions from surfactants. solution as insoluble materials. Builders, in addition to softening, provide a desirable level of alkalinity (increase pH), which aids in cleaning. They also act as buffers to maintain proper alkalinity in wash water. Finally, builders help emulsify oily and greasy soil by breaking it up into tiny globules. Many builders will actually Some common chelating agents used in peptize or suspend loosened dirt and keep industrial cleaning compounds include it from settling back on the cleaned phosphates, EDTA (ethylene diamine tetra surface. Below are three of the most acetate), NTA, gluconic acid, sodium common builders used in today's heavy- citrate, and zeolite compounds. duty detergents. A short description of each follows. Organic chelating agents, which are used in formulation in water conditioners, are more efficient than are phosphates in sequestering calcium and magnesium ions EDTA and in minimizing scale buildup. Most Ethylene Diamine organic agents are salts of EDTA. Tetra Acetate 3. Builders The chelating process, though very effective, is not always necessary and adds to the cost of formulating detergents. NTA Builders are often a multifuctional Nitrilo Triacetic Acid alternative and they are cheaper. Builders are added to a cleaning compound to upgrade and protect the cleaning Phosphates, usually sodium efficiency of the surfactant(s). Builders tripolyphosphate (STPP), have been used have a number of functions which help to as builders extensively in heavy-duty reduce the hardness of the water, buffer the industrial detergents. They combine with solution, and emulsify the soil. hardness minerals to form a soluble Builders soften water by deactivating complex which is removed with the wash hardness minerals (metal ions like calcium water. They also sequester dissolved iron and magnesium. They do this through one and manganese which can interfere with of two ways: detergency. Sequestration - holding metal ions in solution. Compiled by Deniz Kaya -6-
  7. 7. Solvents are chemical substances that can dissolve, suspend, or extract other materials, usually without chemically changing either the solvents or the other Sodium tripolyphosphate materials. Solvents can be organic, (STPP) Na5P3O10 meaning the solvent contains carbon as part of its makeup, or inorganic, meaning Sodium carbonate (soda ash) is used as a the solvent does not contain carbon. For builder but can only soften water through example, "rubbing" alcohol (isopropyl precipitation. Precipitated calcium and alcohol) is an organic solvent, and water is magnesium particles can build up on an inorganic solvent. Hydrocarbon surfaces, especially clothing, and therefore (aliphatic and aromatic hydrocarbons) and sodium carbonate is not used in laundry oxygenated solvents (alcohols, glycol detergents. ethers ketones, esters, and glycol ether esters) are examples of types of organic solvents that can effectively dissolve many materials. Water is a solvent that dissolves many things. But water cannot dissolve Sodium carbonate / Na2CO3 everything. For example, water will not dissolve oily/greasy substances. That is Sodium silicate serves as a builder in because solvents work on the principle of some detergents when used in high “like dissolves like.” Water has chemical concentrations. When used in lower characteristics that are very different from concentrations, it inhibits corrosion and greases. In order to dissolve things that adds crispness to detergent granules. water cannot, other solvents are needed. Sodium silicate is the common name for a These solvents are chemically much more compound sodium metasilicate. similar to greases and, therefore, can effectively dissolve them. Water makes up a large percentage of most liquid cleaner formulas. It is not uncommon for water-based detergents to contain 50% water or more. Some ready- Sodium metasilicate / Na2SiO3 to-use formulations may contain as much as 90% to 95% water. 4. Solvents Water can be considered an active Solvents can be found in a wide variety of ingredient that actually adds to the applications. Coatings, cleaners, personal detergency of cleaners. It performs several care products, inks, adhesives, very important functions in liquid cleaners. pharmaceuticals, and agricultural products Most importantly, it adds to the all benefit from the performance "detergency" of a cleaner. Water acts as a advantages of modern solvents. solvent that breaks up soil particles after the surfactants reduce the surface tension Compiled by Deniz Kaya -7-
  8. 8. and allow the water to penetrate soil (water is commonly referred to as “the universal BHT - Butylated solvent”). hydroxdytoluen e C15H24O Water also aids in the suspension and anti- redeposition of soils. Once the soil has been dissolved and emulsified away from BHT is a lipophilic (fat-soluble) organic the surface, we want to prevent it from compound that is primarily used as being redeposited. Water keeps the soil an antioxidant (E321) . Oxygen reacts suspended away from the clean surface so preferentially with BHT rather than that it can be carried away easily during oxidizing fats or oils, thereby protecting the rinsing process. It is clear that without them from spoilage. this water, our cleaning formulas would be much less effective. Stannic chloride In addition to water, other chemical pentahydrate solvents are often added to cleaners to (SnCI4-5H2O) boost performance. Compounds such as 2- Butoxyethanol (EGBE), isopropyl alcohol (rubbing alcohol) and d-Limonene are all considered solvents. Their main function is Stannic chloride (SnCI4) is a caustic liquid to liquefy grease and oils or dissolve solid used in soaps as a colour and perfume soil into very small particles so surfactants stabilizer and bacteria and fungi control. can more readily perform their function. In detergents, preservatives are used to 5. Preservatives prevent bacteria from spoiling the solution. Methyl paraben and propyl paraben are A preservative is nothing more than a very common for this application. substance that protects soaps and Detergents would not be preserved if they detergents against the natural effects of weren't biodegradable. Bacteria found in aging such as decay, discoloration, air, waste treatment systems and in soil oxidation and bacterial degradation. decompose the surfactants and other Synthetic detergents are preserved ingredients found in our cleaners once they differently from soaps. enter into the environment. In soaps, preservatives are used to forestall Methyl Paraben the natural tendency to develop rancidity and oxidize upon aging. Butylated C8H8O3 hydroxdytoluene (BHT) and stannic chloride are commonly used in this application. Also used in small amounts is Propyl Paraben EDTA. C10H12O3 Compiled by Deniz Kaya -8-
  9. 9. Methylparaben and Propylparaben are and others work to kill microorganisms from the paraben family of chemicals. Due and bacteria. Due to its small size, the to their antimicrobial properties, the are hypochlorite anion (ClO-) kills bacteria by used extensively as a water-soluble diffusing through the bacteria's cell wall preservative in many foods, beverages, and disrupting its ability to function. The pharmaceuticals, detergents and personal compound attacks lipids in the cell wall, care products. causing destruction of enzymes and other parts of the cell, leaving the bacteria 6. Bleaches – Oxidizing Agents harmless . Although bleach can be a useful disinfectant and stain remover, it is a A bleach is a chemical that removes colors dangerous chemical that can inflict harm to or whitens, often via oxidation. Oxidizing human cells the same way it attacks agents used in detergent application are unwanted bacteria. sodium hypochlorite (NaClO) (chlorine bleach) and perborate (oxygen bleach The process of bleaching can be which contains hydrogen peroxide or a summarized in the following set of peroxide-releasing compound) chemical reactions: Cl2(aq) + H2O(l) H+(aq) + Cl-(aq) +HClO(aq) Sodium hypochlorite The H+ ion of the hypochlorous acid then (NaClO) dissolves into solution, and so the final result is effectively: There are several kinds of bleach, but the Cl2(aq) + H2O(l) 2H+(aq) + Cl-(aq) + ClO-(aq) most widespread form is chlorine bleach, chemically known as sodium hypochlorite. Hypochlorite tends to decompose into Bleach eliminates stains because it breaks chloride and a highly reactive form of apart the bonds of the chromophores in molecules. Chromophores are the parts of oxygen: molecules responsible for color. Through ClO- Cl- + O an oxidation reaction that breaks these bonds, bleaching makes the compounds This oxygen then reacts with organic colorless. Therefore, the stain can no substances to produce bleaching or longer be seen. A reducing bleach Works by changing the double bond in antiseptic effects. chromophores to a single bond, once again 7.Enzymes making the compounds that cause a stain colorless. Enzymes are proteins, composed of hundred of amino-acids, which are The chlorine in bleach also helps kill produced by living organisms. They are bacteria because it disrupts their biological responsible for a number of reactions and processes. When chlorine bleach is added biological activities in plants, animals, to water, it forms many different human beings and micro-organisms. They chemicals, one example being are found in the human digestive system to hypochlorous acid (HOCl). This chemical Compiled by Deniz Kaya -9-
  10. 10. break down carbohydrates (sugars), fats or combined effect of surfactants and proteins present in food. enzymes, stubborn stains can be removed from fibres. The most important reasons to use enzymes in detergents are Lipases I. that a very small quantity of these Though enzymes can easily digest protein inexhaustible bio-catalysts can replace stains, oily and fatty stains have always very large quantity of man made been troublesome to remove. The trend chemicals towards lower washing temperatures has made the removal of grease spots an even II. enzymes can work at very low bigger problem. This applies particularly to temperature at which traditional materials made up of a blend of cotton and chemistry quite often is no longer polyester. The lipase is capable of effective removing fatty stains such as fats, butter, salad oil, sauces and the tough stains on III. they are fully biodegradable. All these collars and cuffs. characteristics make enzymes - on top of their high efficiency - environmentally Amylases friendly ingredients. Amylases are used to remove residues of Proteases starch-based foods like potatoes, spaghetti, custards, gravies and chocolate. This type Proteases are the most widely used of enzyme can be used in laundry enzymes in the detergent industry. They detergents as well as in dishwashing remove protein stains such as grass, blood, detergents. egg and human sweat. These organic stains have a tendency to Cellulases adhere strongly to textile fibres. The proteins act as glues, preventing the water The development of detergent enzymes has borne detergent systems from removing mainly focused on enzymes capable of some of the other components of the removing stains. However, a cellulase soiling, such as pigments and street dirt. enzyme has properties enabling it to modify the structure of cellulose fibre on The inefficiency of non enzymatic cotton and cotton blends. When it is added detergents at removing proteins can result to a detergent, it results into the following in permanent stains due to oxidation and effects: denaturing caused by bleaching and drying. Blood, for example, will leave a Colour brightening: When garments made rust coloured spot unless it is removed of cotton or cotton blends have been before bleaching. washed several times, they tend to get a 'fluffy' look and the colours become duller. Proteases hydrolyse proteins and break This effect is due to the formation of them down into more soluble polypeptides microfibrils that become partly detached or free amino acids. As a result of the from the main fibres. The light falling on Compiled by Deniz Kaya - 10 -
  11. 11. the garment is reflected back to a greater extent giving the impression that the colour is duller. These fibrils, however, can be degraded by the cellulase enzyme, restoring a smooth surface to the fibre and restoring the garment to its original colour. Softening: The enzyme also has a significant softening effect on the fabric, probably due to the removal of the microfibrils. Soil removal: Some dirt particles are trapped in the network of microfibrils and are released when the microfibrils are removed by the cellulase enzyme. Compiled by Deniz Kaya - 11 -