Syndets synthetic

The solubihty characteristics of sodium acyl isethionates allow them to be used in synthetic detergent (syndet) bars. Complex blends of an isethionate and various soaps, free fatty acids, and small amounts of other surfactants reportedly are essentially nonirritant skin cleansers (66). As a rule, the more detersive surfactants, for example alkyl sulfates, a-olefin sulfonates, and alkylaryl sulfonates, are used in limited amounts in skin cleansers. Most skin cleansers are compounded to leave an emollient residue on the skin after rinsing with water. Free fatty acids, alkyl betaines, and some compatible cationic or quaternary compounds have been found to be especially useful. A mildly acidic environment on the skin helps control the growth of resident microbial species. Detergent-based skin cleansers can be formulated with abrasives to remove scaly or hard-to-remove materials from the skin. 

Surface-active compounds, especially the anionic surfactants, are derived from fossil raw materials as well as from recent raw materials. The portion of the biomass on the production of anionic surfactants is about 75% if the soap, the quantitatively most important anionic surfactant, is included. Considering only the synthetic surfactants, the syndets, the portion of fossil raw materials in the production of these surfactants, is about 75%. Without the lignosulfonates (and the petroleum sulfonates) this portion is about 90%. Due to strong efforts... 

Concerns about the effect of TPP on eutrophication have led many states, cities, and regional governments to ban the use of the compound in syndets. Such bans have caused serious problems for detergent manufacturers, however, because no entirely satisfactory substitute for TPP has yet been found. Two promising candidates are the sodium salt of nitrilotriacetic acid, 3Na, N(CH2C02)3 , or NTA and ethylenediaminetetraacetic acid (EDTA). Both of these compounds act in much the same way as TPP, that is, by sequestering metal ions. Other builders that have been incorporated into syndet formulations include sodium carbonate, synthetic zeolites, borates, and organic polymers known as polycarboxylates. 

Environmental Response, Compensation, and Liabihty Act of 1980, designed to find and remediate toxic waste sites in the United States, syndet An abbreviation for the term synthetic detergent. synthetic detergent A cleaning product made of synthetic materials rather than natural soaps. 

Synthetic detergents (syndets) belong to the group of surface active agents [which are substances which affect (usually reduce) surface tension when dissolved in water or in water solns] and have structurally unsymmetrical molecules contg both hydrophilic, or water-soluble, groups and hydrophobic, or oil-soluble hydrocarbon chains... 

The chemistry of soap manufacturing stayed essentially unchanged until World War II, at which time synthetic detergents (syndets) became available. There had been a search for cleansing agents that would foam and clean when added to seawater in response to the need of sailors who spent months at sea under severe freshwater restrictions. 

Almost as a rule, the solubility of soap in water increases with an increase in the size of the monovalent cation (base) however, an increase in the size of a divalent cation (Mg+2, Ca+2) results in a decrease in the solubility. An increase in the chain length of the fatty acid moiety of soap results in a decrease in the solubility of soap, whereas the presence of unsaturation results in an increase in its solubility. In general, an increase in the water solubility is accompanied by an increase in the softness and use-up properties of soap. Adequate solubility results in good performance in soft water, although in hard water, lather decreases due to the formation of insoluble Ca+2 and Mg+2 salts. Cleansing bars formulated with various levels of synthetic detergents (corn-bars or syndets) provide improved performance in hard water conditions. 

There is a worldwide tendency to replace conventional soaps (made from fats and oils derived from animals and plants) with synthetic detergents (syndets) from petroleum sources. In developed countries syndets have replaced soaps to the extent of 70-80%. In India, the situation is nearly the reverse the total estimated production of soaps exceeds 700,000 tons, while that of syndets is only 100,000 tons. With the increasing demand for soap, the import of oils and fats tends to increase tremendously, affecting not only the soap industry but also the edible oils industry which is closely linked to it and also is subject to an ever-increasing demand (based on the improving standards of living and the increase in population—625 million in 1977). 

The chemo-, regio- and stereo-selectivity observed in the Patemo-Biichi photocycloaddition make the reaction a valuable synthetic method as its numerous applications to targets in synthesis attest. This review will summarize the important mechanistic and syndetic advances. Knowledge of these precedents will likely initiate further scrutiny and applications of the reaction to the synthesis of architecti ly complex targets. 

The increased use of synthetic detergents ( syndets ) can create problems of taste and foaming in the re-use of water. These syndets, measured as alkyl benzene sulfonate (ABS), are not removed by conventional sewage treatments and are not eliminated by water purification processes of coagulation, disinfection, and filtration. Based on an analysis of a number of streams, as of now the concentration of syndets in most streams is below levels that cause difficulties from foam or taste. With the increasing use of syndets, however, the situation could become significant, especially where many communities are located on a single stream with the consequent repeated re-use of the water. 

Syndet sin- de n. A contraction for the term synthetic detergent used loosely to signify synthetic detergents or compositions containing synthetic detergents. 

Synthetic detergent n. A detergent produced by chemical synthesis and comprising an organic composition other than soap. Often contracted to syndet. 

Laundry bars can be divided into two main categories—soap bars and syndet bars. In some markets, combars are available, which contain both soap and synthetic detergent Soap bars are generally more mild to the skin than syndet bars, but syndet bars are usually more efficacious, especially at high water hardness. Consumers will choose a laundry bar based on their habits and practices, desired level of efficacy, and their economic situation. 

Soap scum cleaners are by far the largest group of bathroom cleaners. Soap scum is a prevalent problem in almost any bathroom. Hard water deposits are more of a problem in very hard waters area such as Europe, but the precipitatiou of soap caused by hard water salts can become a problem even in areas with moderate hard water. This tends to be less of a problem in households that use shower gels or synthetic detergent (syndet) bars, because the detergents used in these products are... 

SCI, sulfosuccinates, AGES, and CMOS are the main synthetic detergents used in com-bars and syndet bars. The KP of surfactants plays a very important role in the selection of a particular surfactant for the product. Vel Beauty Bar, launched by Colgate in 1948, was the first syndet bar, followed by Zest and Dove in 1952 and 1955, respectively, by P G and Lever Brothers. 

Combo bars are products having active ingredients by combination of a synthetic and soap. The soap base should be at least 10%. Although combo bars are often considered cleansing bars based on soaps to which some lime-soap dispersants are added, their look and performance characteristics are generally closer to a syndet rather than a toilet soap. This is because the synthetic active ingredient is more effective than soap. 

Crumbling of a synthetic extrusion bar is possible if there is a defect in the plasticizer and binder. Syndet hydrophilic groups are larger and are distributed over a longer section of the molecule, and their hydrophobic groups tend to be shorter, on an average, than the distribution found in soaps. This implies an increased solubility and decreased intermolecular adhesion in syndets when compared to soaps. 

A more prolonged rinsing is required when a syndet is used rather than soap. Synthetic bars offer good resistance to cracking tendency. This phenomenon is not worthy of attention for syndets, although it is negatively important for soap. 

Table 5.1 Conosion Data for Zinc and Zinc Coatings with Detergents, Cleaners, Soaps, Synthetic Detergents (Syndets), etc. 

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