Ammonium salts cetyltrimethylammonium chloride

Fig. 10.8 A where the R substituents are alkyl or heterocyclic radicals to give compounds such as cetyltrimethylammonium bromide (cetrimide), cetylpyridinium chloride and benzalkonium chloride. Inspection of the stmctures of these compounds (Fig. 10.8B) indicates the requirement for good antimicrobial activily of having a chain length in the range Cg to Cig in at least one of the R substituents. In the pyridinium compounds (Fig. 10.8C) three of the four covalent links may be satisfied by the nitrogen in a pyridine ring. Polymeric quaternary ammonium salts such as polyquatemium 1 are finding increasing use as preservatives.

The metal-catalysed autoxidation of alkenes to produce ketones (Wacker reaction) is promoted by the presence of quaternary ammonium salts [14]. For example, using copper(II) chloride and palladium(II) chloride in benzene in the presence of cetyltrimethylammonium bromide, 1-decene is converted into 2-decanone (73%), 1,7-octadiene into 2,7-octadione (77%) and vinylcyclohexane into cyclo-hexylethanone (22%). Benzyltriethylammonium chloride and tetra-n-butylammo-nium hydrogen sulphate are ineffective catalysts. It has been suggested that the process is not micellar, although the catalysts have the characteristics of those which produce micelles. The Wacker reaction is also catalysed by rhodium and ruthenium salts in the presence of a quaternary ammonium salt. Generally, however, the yields are lower than those obtained using the palladium catalyst and, frequently, several oxidation products are obtained from each reaction [15]. 

Thiourea dioxide (aminoiminomethanesulfinic acid) reduced diaryl ditellurium and divinyl ditellurium derivatives in tetrahydrofuran, to which an ammonium salt such as cetyltrimethylammonium chloride, serving as a phase-transfer catalyst, and 50% aqueous sodium hydroxide had been added4,5. 

The cationic detergents invariably contain amino compounds. The most widely used would be the quaternary ammonium salts, such as cetyltrimethylammonium chloride, a well-known germicide and di-stearyldimethylammonium chloride (DSDMAC), known as fabric softener for cotton diapers and as a laundry rinse-cycle fabric softener [4]. 

Quaternary alkylammonium salts, tertiary amines, and crown ethers have all been utilized as catalysts in the reaction of hydroxide with chloroform to yield dichlorocarbene. The most commonly utilized catalyst has been benzyltriethylammonium chloride (see Sect. 1.7) but other quaternary ammonium chloride catalysts have proved effective. Cetyltrimethylammonium chloride and tricaprylmethylammonium chloride (Aliquat 336) have both been used effectively in the cyclopropanation of simple alkenes. The use of Z e a-hydroxyethyltrialkylammonium hydroxides as phase transfer catalysts results in increased regioselectivity in the addition of dichlorocarbene to olefins [12]. Crown ethers such as dibenzo and dicyclohexyl-18-crown-6 have both been utilized in place of quaternary ammonium compounds. 18-Crown-6 has also been used as a catalyst in the phase transfer thermal decomposition of sodium trichloroacetate to yield dichlorocarbene [13]. 

Hair lotions are for daily application to keep the hair tidy and the scalp in good condition. The lotions are mixtures of water and ethanol, which contain small amoimts of active agents for hair and scalp. Such agents are - glycerol, - quaternary ammonium compoimds, e.g., cetyltrimethylammonium chloride, and anti-dandruff agents, e.g., pir-octone olamine [the ethanolamine salt of 1-hy-droxy-4-methyl-6-(2,4,4-trimetylpentyl)-2-( 1H) pyridon]. Users of hair lotions usually are men, because big amounts of water used as well as shampooing destroy the style. 

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