Quaternary ammonium compounds biocides

Quaternary ammonium compounds biocidal activity mechanism, 1, 401 toxicity, 1, 124 Quaternization heterocyclic compounds reviews, 1, 73 ( )-Quebrach amine synthesis, 1, 490 Queen substance synthesis, 1, 439 4, 777 Quercetin occurrence, 3, 878 pentamethyl ether photolysis, 3, 696 photooxidation, 3, 695 Quercetrin hydrolysis, 3, 878 Quinacetol sulfate as fungicide, 2, 514 Quinacridone, 2,9-dimethyl-, 1, 336 Quinacridone pigments, 1, 335-336 Quinacrine... 

Sanitisers Quaternary ammonium compounds Biocidal activity... 

Biocides - [AMNES-CYCLOALIPHATIC AMINES] (Vol 2) - [INDUSTRIALANTIMICROBIALAGENTS] (Vol 14) - [THERMAL POLLUTION] (Vol 23) -m adhesives [VINYL POLYMERS - VINYLACETATE POLYMERS] (Vol 24) -dicyandiarmdes m [CYANAMIDES] (Vol 7) -m grouts [SOIL STABILIZATION] (Vol 22) -mtro alcohols as [NITRO ALCOHOLS] (Vol 17) -m papermaking [PAPERMAKING ADDITIVES] (Vol 18) -m papermaking [PAPERMAKING ADDITIVES] (Vol 18) -PVC as [VINYL POLYMERS - VINYL CHLORIDE POLYMERS] (Vol 24) -quaternary ammonium compounds as [QUATERNARY AMMONIUM COMPOUNDS] (Vol 20)... 

Fatty Amines. Fatty amines are the most important nitrogen derivatives of fatty acids. They are produced by the reaction of fatty acids with ammonia and hydrogen. They are the bases for the manufacture of quaternary ammonium compounds used as fabric softeners and biocides. Fatty amine oxides are mild to the skin with good cleaning and foaming properties and find application as a shampoo ingredient. The above mentioned products are but some of the oleochemical derivatives from coconut fatty acids (5). 

Biocides probably have multiple target sites on viral particles and the overall damage caused results in loss of viral infectivity (Table 5.1). When compared to bacterial cells, however, viruses present only a few structural targets to biocides the envelope (when present), the glycoproteins, the capsid and the nucleic acid. The activity of biocides against the viral envelope has not been well documented but it can be expected that membrane-active agents such as phenolics and the cationic biocides (e.g. chlorhexidine and quaternary ammonium compounds — Q ACs) will act against the viral envelope, which is a typical unit membrane. The capsid is... 

Typical biocides include hypochlorous acid, chlorine dioxide, hypobromus acid, hydrogen peroxide, ozone, ultraviolet-light treatment, phenolics, aldehydes, and quaternary ammonium compounds (Ref 73, 80). A brief description of each follows (Ref 73, 80). Hypochlorous acid is probably the most commonly used biocide and also one of the most powerful oxidizing agents. The sources of hypochlorous acid are chlorine gas and sodium hypochlorite. In aque-... 

A number of fatty amines and their derivatives, especially quaternary ammonium compounds, are widely used in formulations for the control of bacteria, fungi, viruses and algae, in disinfectant/sanitizers and wood-preservation applications. Table 14.3 presents the fatty amines and derivatives which are frequently used in biocidal formulations. 

The use of quaternary ammonium compounds as biocides in wood preservation formulations is increasing rapidly. Their low toxicity and biodegradable properties, combined with their favourable adsorption characteristics, have led to an increase in the popularity of these products as an alternative to other wood preservative formulations such as pentachloraphenate (PCP) and chromated copper arsenate (CCA). Due to growing environmental pressure, the use of these latter products is declining and the development of alternative wood preservatives is gaining momentum. 

Used by themselves, or in combination with other modem biocides - such as systematic fungicides, bactericides or insecticides - the long-alkyl-chain quaternary ammonium compounds offer a useful tool in the development of new environmentally acceptable wood preservative formulations. The most commonly used quaternary ammonium compounds are coco(fractionated) benzyldimethylammonium chloride and didecyldimethylammonium chloride. 

Anionic surfactants are little used in breweries while cationic surfactants such as quaternary ammonium compounds are employed for certain biocidal applications. Ampholytic (amphoteric) surfactants are also used as biocides and like the quaternary ammonium compounds they have to be rigorously... 

Although phenols, chlorophenols, alcohols, hypochlorites, and iodophors are used as active biocide agents against certain strains of bacteria in some applications, formulations with quaternary ammonium compounds as the active biocide ingredients account for the majority of all l I sanitizers and disinfectant products. A variety of known quaternary ammonium compounds are effective, but the quaternary compound of choice is dialkyl dimethyl ammonium chloride. 

Effect of combination of non-oxidizing biocides. Experimental study shows that the combination of nonoxidizing biocides was more efficacious in biofilm control than biocides when used alone (Figure 9). Simultaneous use of isothiazolones (4 ppm) and quaternary ammonium compound (12 ppm) demonstrated better biofilm control than either isothiazolones or quat alone. This biocidal combination controlled biofilm (based on HTR data) for about 27, 30, and 32 hours after three consecutive treatments. The biofilm DO response was much more significant than any separately tested biocide and was similar to the test when isothiazolone was used together with oxidizing biocide. These laboratory results confirmed practical (field) evidence that combinations of biocides affect biofibns more effectively than biocides used alone. 

Other considerations. Other considerations for an injection water biocide include whether the system can tolerate a biocide that foams. Quaternary ammonium compounds are effective biocides but some quats have a tendency to foam. Lastly, safety and handling considerations are very important in the choice of a biocide. All biocides should be handled with extreme care so it is critical that the choice of a biocide includes a complete and thorough evaluation and understanding of the safety requirements detailed in the Material Safety Data Sheets for each product. 

General information. Aqueous solutions of formaldehyde are generally used both as biocides and as hydrogen sulfide scavengers in the oilfield. It is very common for formaldehyde to be used in combination with quaternary ammonium compounds, glutaraldehyde and THPS (see 5.4.7.). Solutions of formaldehyde tend to be inexpensive (relative to the other commonly used biocides), so it continues to be widely used. 

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