Surfactants as detergents

The widespread use of cationic surfactants as detergents and disinfectants in many different home- and industrial-cleaning products suggests its likely presence in the aquatic environment, such as in surface water from WWTP. Environmental detections of cationic surfactants have been reported at the submicrogram-per-htre level in water and sediment matrices. The presence of surfactants in surface water also suggests potential toxicity for organisms, such as fish... 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and fumes Uses Surfactant as detergent, emulsifier, wetting agent, dispersant, stabilizer, defoamer intermediate in synthesis of anionic surfactants... 

Explore some commercial applications of surfactants as detergents and emulsifiers and familiarize yourself with the Langmuir trough apparatus. 

Of the higher alkyinaphthalenes, those of importance are the amyl-, diamyl-, polyamyl-, nonyl-, and dinonylnaphthalenes. These alkyinaphthalenes are used in sulfonated form as surfactants and detergent products. 

Alkylation. Benzene and phenol feedstocks are readily alkylated under Friedel-Crafts conditions to prepare extensive families of alkylated aromatics. These materials generally are intermediates in the production of surfactants or detergents such as linear alkylbenzenesulfonate (LABS) and alkylphenolethoxylate (APE). Other uses include the production of antioxidants, plasticizers, and lube additives. 

Fabric Softening. The use of quaternary surfactants as fabric softeners and static control agents can be broken down into three main household product types rinse cycle softeners tumble dryer sheets and detergents containing softeners, also known as softergents. Rinse cycle softeners... 

Sucrose monoesters (SMEs) are used as nonionic surfactants, in detergents and as emulsifiers in foods. Some SMEs have bacteriostatic activity and are used to prevent spoilage in beverages. Semperfresh, an SME produced in the U.K., is used as a coating to extend the shelf life of fmits and vegetables (21,29). 

Many benzenoid quaternary cationic surfactants possess germicidal, fungicidal, or algicidal activity. Solutions of such compounds, alone or in combination with nonionic surfactants, are used as detergent sanitizers in hospital maintenance. Classified as biocidal products, their labeling is regulated by the U.S. EPA. The 1993 U.S. shipments of cationic surfactants represented 16% of the total sales value of surfactant production. Some of this production is used for the preparation of more highly substituted derivatives (101). 

Health and Safety Factors As a class, surfactants and detergent products are among the most widely used chemical compositions. Almost everyone is exposed to these products on a daily basis ia situatioas that range from ingestion of food-grade emulsifiers to intimate coatact of skin and eyes with personal-care and laundry products. Safety is therefore a matter of great importance (132,133). Ranges of surfactant LD q values are shown ia Table 2. 

The introduction of surfactant products into the environment, after use by consumers or as part of waste disposed during manufacture, is regulated by the Clean Water Act, the Clean Air Act, and the Resource Conservation and Recovery Act. In this respect, surfactants are subject to the same regulations as chemicals in general. There are, however, two areas of specific relevance to surfactants and detergent products, ie, biodegradabiUty and eutrophication. 

The DATs present in LAB will readily sulfonate to form dialkyltetralin-sulfonate or DATS. The foam and detergency performance properties of individual C DATS homologs are very similar to that of the corresponding C j LAS homologs [21]. Thus, even at a level of 10% DATS in the LAB, no decrease in foam or detergency performance is observed. In some liquid formulations, the presence of DATS can provide a beneficial hydrotropic effect to LAS [22]. Figure 8 illustrates that DATS are indeed surfactants, as evidenced by their surface tension vs. concentration plot. 

As detergent manufacturers responded to consumer trends the number of mixed active detergent products increased. The combination of LAS with other surfactants in mixed active systems can provide several advantages over a single active LAS system. These advantages can include the following ... 

The solubility of numerous ionic surfactants in water is strongly reduced in the presence of divalent cations. Stability in hard water is thus an important fact for surfactants used as detergents. Their stability can be measured as the amount of divalent cations at which the formation of a poorly soluble surfactant salt leads to permanent turbidity. The values given in the literature can only be... 

Stable liquid detergents are obtained by polyacetalcarboxylate builders, ionic or nonionic surfactants, and common ingredients of detergents. If esters of phosphoric acid are used as anionic surfactants a detergent of this kind with 62% of water retained a single phase after a 30-day storage [213]. 

Because the reaction of an amine with an acyl chloride is much faster than the hydrolysis of the acyl chloride, the reaction can usually be carried out in an aqueous alkali solution. This is well known as the Schotten-Baumann procedure.6 For example, a number of N-acyl taxol analogs have been prepared under Schotten-Baumann conditions by the reaction of A-debenzoyltaxol with various acid chlorides (Eq. 9.4).7 Highly purified /V-long-chain-acyl neutral amino acids such as potassium AMauroyTy-aminobutyrate, useful as surfactants for detergent... 

Fig. 4.5 Detergency of C12E4 and C12E5 against hexadecane as a function of temperature (left side) and the corresponding three-phase ranges for these surfactants as a function of the number n of carbon atoms of alkanes [46],...

APEOs are used in domestic and industrial applications. They are applied as detergents, emulsifiers, wetting agents, dispersants or solubilisers. APEO derived from nonylphenol (NP), i.e. nonylphenol ethoxylates (NPEOs) comprises about 80% of the total market volume, while octylphenol-derived surfactants (OPEOs) account for 15-20%. Because of the persistence and toxicity of some degradation intermediates, their use has been reduced in several countries either through voluntary bans by the chemical industry or by legal regulations. However, excellent properties in combination with comparably low production costs hampers their complete replacement with other more environmentally acceptable alternatives. 

Unlike many other enzymes, the subtilisins are fairly stable towards e.g. organic solvents, anionic surfactants, high temperatures and high pH. This makes the subtilisins very suitable as detergent proteases. But despite this fact, stabilization of these protease enzymes in liquid detergents remains a major issue. 

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