Builders, detergent 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 conventional detergent builders [viz., sodium tripolyphosphate (STPP) and tetra sodium pyrophosphate (TSPP)], have been identified as environmentally unsafe as they cause excessive deposition of phosphates in the water bodies and result in eutrophication. This is a process which causes excessive growth of algae in water bodies, which once died and decomposed, can cause growth of organic... 

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. 

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. 

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 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. 

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]. 

FIG. 8.13 Sequestration of water hardness ions by detergent builders. Sodium polyacrylate Mw = 170,000, STPP (sodium tripolyphosphate), NTA (nitrilotriacetic acid), EDTA (ethylenediamine tetraacetic acid), sodium citrate, CMOS (sodium carboxymethoxysucci-nate), sodium carbonate, zeolite A. (Reproduced from Nagarajan, M.K., J. Am. Oil Chem. Soc., 62, 949, 1985. With permission.)... 

Comparable results were obtained in formulations containing sodium silicate as a builder together with (M-5% sodium tripolyphosphate, using 250 ppm hard water and a bath temperature of 49°C (Illman, 1971). A nonionic surfactant prepared by polyoxyethylenation of a C12-15 alcohol mixture with 9-11 mol of ethylene oxide generally showed similar detergency to an anionic prepared by sulfation of a Ci2 i5 alcohol mixture previously polyoxyethylenated with 3 mol of ethylene oxide at all percentages of sodium tripolyphosphate, and both were considerably superior to a linear tridecylbenzenesulfonate and a sulfated C16-I8 alcohol mixture. The nonionic was somewhat better than the sulfated POE alcohol for removing nonpolar fatty soil from Dacron-cotton permapress, and the reverse was true for the removal of polar soil from Dacron-cotton permapress and carbon soil from cotton, but similar results for the two surfactants were obtained for clay removal from both Dacron-cotton permapress and cotton, and polar and nonpolar fatty soil from cotton. 

Sodium tripolyphosphate, Na5P30io, is called a builder when added to detergents. It helps to create the conditions in laundry water necessary for the detergents to work most efficiently. When phosphoric acid, H3PO4, is combined with sodium carbonate, three reactions take place in the mixture that lead to the production of sodium tripolyphosphate. Write a balanced equation, without including states, for each of the reactions ... 

The second problem with detergents has been the use of sodium tripolyphosphate (8.47) as a builder (i.e., an agent to sequester the calcium and magnesium ions in the water). This has caused eutrophication (excessive growth of algae) of lakes and rivers receiving waste water.269... 

The salts of the above acids are known as polyphosphates and are used extensively in industry (including water treatment), predominantly due to their strong metal ion complexing abilities (sequestering agents). A common example is sodium tripolyphosphate (STPP) or Na5P30io, which is used extensively as a builder for household detergents. 

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