Detergents sodium tripolyphosphate

Phospha.tes, Pentasodium triphosphate [7758-29-4] sodium tripolyphosphate, STPP, Na P O Q, is the most widely used and most effective builder in heavy-duty fabric washing compositions (see also Phosphoric acid and phosphates). It is a strong sequestrant for calcium and magnesium, with a p c of ca 6, and provides exceUent suspending action for soils. Because of its high sequestration power, it also finds extensive appHcation in automatic-dishwashing detergents. Sodium tripolyphosphate forms stable hydrates and thus aids in the manufacture of crisp spray-dried laundry powders. 

The hydration rate of sodium tripolyphosphate to its stable hexahydrate, Na P O Q 6H20, directly affects detergent processing and product properties. The proportion of STP-I (fast-hydrating form) and STP-II (slow-hydrating form) in commercial sodium tripolyphosphate is controUed by the time—temperature profile during calcination. In most processes, a final product temperature of near 450°C results in a product containing about 30%... 

Sequestration forms the basis for detergent and water-treatment appHcations of polyphosphates. Sequestration of hardness ions by sodium tripolyphosphate used in detergent formulations prevents the precipitation of surfactants by the hardness ions. Sodium polyphosphate glass (SHMP) may be added to water system to prevent the formation of calcium or magnesium scales by reducing the activity of the hardness ions. However, if the ratio of cation to polyphosphate is too high at a given pH, insoluble precipitates such as may result instead of the soluble polyphosphate complexes. The... 

The largest use of calcium hypochlorite is for water treatment. It is also used for I I and household disinfectants, cleaners, and mildewcides. Most of the household uses have been limited to in-tank toilet bowl cleaners. In areas where chlorine cannot be shipped or is otherwise unavailable, calcium hypochlorite is used to bleach textiles in commercial laundries and textile mills. It is usually first converted to sodium hypochlorite by mixing it with an aqueous solution of sodium carbonate and removing the precipitated calcium carbonate. Or, it can be dissolved in the presence of sufficient sodium tripolyphosphate to prevent the precipitation of calcium salts. However, calcium hypochlorite is not usually used to bleach laundry and textiles because of problems with insoluble inorganic calcium salts and precipitation of soaps and anionic detergents as their calcium salts. 

Tetrasodium pyrophosphate [7722-88-5] Na4P20y, is another important primary builder and detergent. In sequestration, it is not quite as effective as sodium tripolyphosphate and its usage in heavy-duty laundry powders has declined in recent years. Functionally, tetrasodium pyrophosphate is both a builder for surfactants (ie, water softener) and alkaH. 

The efforts of the detergent industry toward solution of its part of the eutrophication problem are, at this point, less complete than its response to the biodegradabihty problem. Soda ash, Na2C02, sodium siUcate, and, to a lesser extent, sodium citrate formed the basis of the early formulations marketed in the areas where phosphates were harmed. Technically, these substances are considerably less effective than sodium tripolyphosphate. As a precipitant builder, soda ash can lead to undesirable deposits of calcium carbonate on textiles and on washing machines. 

C in a Terg-o-Tometer. They tested commercial AOS, SAS, AS, and LAS detergents in two formulations one contains surfactant (25%) and sodium sulfate (75%) and is called a light-duty dishwash formulation. The other one contains surfactant (25%), sodium tripolyphosphate (35%), sodium silicate (8%), carboxymethylcellulose (1%), and sodium sulfate (31%), and is called a heavy-duty dishwash liquid. The results in Table 26 show that the AOS-containing formulations have superior performance, followed by SAS, AS, and LAS. 

Addition of suitable builders, such as sodium silicates or sodium tripolyphosphate, could increase the detergency of soap-LSDA blend even further. A systematic investigation of three-component systems, soap-LSDA builder, showed that a detergency maximum could be attained which corresponded to a certain fixed ratio of components. Maximum detergency corresponded to an approximate composition of 75% soap, 10% MES, and 15% metasilicate. The tests were carried out at 50°C and at 300 ppm water hardness which is well above that of U.S. municipal water supplies. The principle of detergency potentiation of soap by an LSDA and builder was always evident, even when using other artificially soiled cloths, such as those supplied by U.S. Testing Co. or Testfabrics Inc. 

Sodium tripolyphosphate, Na5P3O10, is the most important salt of the polyphosphoric acids. It is used in sulfonate detergents, in which it functions to complex with Ca2+ and Mg2+ (known as sequestering) to prevent the formation of insoluble soaps in hard water. 

Sodium tripolyphosphate is the main phosphate found in detergents. It acts as a water softener and counteracts the elements that are responsible for hard water while at the same time making the detergent a more effective cleaner. 

The manufacture of phosphorus-derived chemicals is almost entirely based on the production of elemental phosphorus from mined phosphate rock. Ferrophosphorus, widely used in the metallurgical industries, is a direct byproduct of the phosphorus production process. In the United States, over 85% of elemental phosphorus production is used to manufacture high-grade phosphoric acid by the furnace or dry process as opposed to the wet process that converts phosphate rock directly into low-grade phosphoric acid. The remainder of the elemental phosphorus is either marketed directly or converted into phosphoms chemicals. The furnace-grade phosphoric acid is marketed directly, mostly to the food and fertilizer industries. Finally, phosphoric acid is employed to manufacture sodium tripolyphosphate, which is used in detergents and for water treatment, and calcium phosphate, which is used in foods and animal feeds. 

The problematic agent in this list are builders, compounds that sequester ("capture") mineral ions such as calcium and magnesium that would otherwise reduce the sudsing properties of a cleaning agent. One of the most effective builders ever discovered, and one that was widely used for many years, is sodium tripolyphosphate (TPP). The structure of this molecule is such that it can surround and trap ions (such as Ga "" and Mg "") that are responsible for the "hardness in water (which reduces the effectiveness of a detergent). 

A chemical compound added into detergent formulations to aid oil emulsification (by raising pH and to complex and solubilize hardness ions). Example sodium tripolyphosphate. 

A builder is a compound that removes calcium and magnesium ions normally present in water, and, as a result, reduces the concentration of surfactants required to carry out the detergent action. Currently, the builder mainly used in practice is sodium tripolyphosphate. However, phosphates are plant nutrients and provoke eutrophication in lakes and streams which receive municipal wastewater contaminated with detergent residuals. Consequently, the use of phosphates in detergents has been restricted. 

Since phosphorus promotes plant growth, phosphates are excellent fertilizers for crops. (Phosphates are chemicals containing phosphorus. You will learn more about phosphates later in this unit.) Phosphates are also used as food additives, and as components in some medicines. In addition, they are an important part of dishwasher and laundry detergents. For example, sodium tripolyphosphate (STPP) acts to soften water, and keep dirt suspended in the water. Before the 1970s, STPP was a major ingredient in most detergents. 

The most important use of sodium tripolyphosphate is as a builder in detergents. However, legislative restrictions on the use of phosphorus compounds in household detergents have... 

FMC textile experts, recognizing the problem, felt that sodium tripolyphosphate (STPP) could be of value as a textile scouring booster. Sodium tripolyphosphate has long been the builder of choice in laundry detergents where it is used to tie up and sequester hard water ions, but it has seen limited use in the textile industry. 

Sodium tripolyphosphate (STP) was commercially available in the mid-1940s and had replaced TSPP because of its superior detergent processing, solubility, and hardness ion-sequestering characteristics. Sequestration is defined as the reaction of a cation with an anion to form a soluble complex. The sequestration of Ca and Mg " ions leads to softened water and is the most important function of any detergent builder [3, 4]. 

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