Dialkyldimethyl

Dialkyldimethyl and alkyltrknethyl quaternaries can be prepared direcdy from secondary and primary amines as shown ia equations 7 and 8, respectively. This process, known as exhaustive alkylation, is usually not the method of choice on a commercial scale. This technique requires the continuous addition of basic material over the course of the reaction to prevent the formation of amine salts (223,224). Furthermore, products such as inorganic salt and water must be removed from the quaternary. The salt represents a significant disposal problem. 

OleFns and Fatty Alcohols. Alkylbenzyldimethylammonium (ABDM) quatematies are usually prepared from a-olefin or fatty alcohol precursors. Manufacturers that start from the fatty alcohol usually prefer to prepare the intermediate alkyldimethylamine direcdy by using dimethylamine and a catalyst rather than from fatty alkyl chloride. Small volumes of dialkyldimethyl and alkyltrimethyl quatematies in the Cg—range are also manufactured from these precursors (Fig. 4). 

Alkylbenzyldimethyl quaternaries (ABDM) are used as disinfectants (49) and preservatives. The most effective alkyl chain length for these compounds is between 10 and 18 carbon atoms. Alkyltrimethyl types, alkyl dimethylbenzyl types, and didodecyl dimethyl ammonium chloride [3401-74-9] exhibit excellent germicidal activity (151—159). Dialkyldimethyl types are effective against anaerobic bacteria such as those found in oil wells (94—97). One of the most effective and widely used biocides is didecyl dimethyl ammonium chloride [7173-57-5]. 

DEQ DM DTD MAC EO FADA LAB LAS M MBAS MCPEG Lever s diester quat dialkyldimethyl ammonium ditallow dimethylammonium chloride ethylene oxide fatty acid diethanolamide linear alkylbenzene linear alkylbenzene sulfonate R3S1O0.5 methylene blue active substances mono carboxylated PEG... 

All four types of polymerizable lipids shown in Fig. 4 have been realized synthetically. In this context, one need not attempt to reproduce mother nature slavishly (Fendler 8)). Kunitake 9) was able to show that simple molecules like dialkyldimethyl-ammonium salts also form bilayer assemblies. Fuhrhop 10) and Kunitake U) could accomplish the formation of monolayer liposomes with molecules containing only one alkyl chain and two hydrophilic head groups. Acryloylic and methacryloylic groups (type a and d, Table 1), as well as diacetylenic, butadienic, vinylic and maleic acid groups (type b and c), have been used as polymerizable moieties. A compilation of amphiphilic, photopolymerizable molecules is given in Table 1. 

Biocidal applications. The use of quaternary ammonium salts in disinfecting systems for household and industrial cleaners has been known for many years [95, 96]. Alkyl-benzyldimethyl quaternaries, alkyltrimethyl quaternaries, and dialkyldimethyl quaternaries are the more commonly used biocidal quaternary ammonium salts [16]. Recently, dialkyldimethyl quaternary ammonium salts have received renewed attention as potential wood preservatives to replace the heavy metal types [97]. Metal-free wood preservative formulations containing dialkyldimethyl ammonium salts with non-halide anions, such as carboxylates, borates, and carbonates, have been developed [98, 99]. 

At present, triethanolamine ester quats (TEAEQ), with a formal structure of (RC02CH2CH2)2N+(CH3)CH2CH2OH-CH3SC>4 are the fabric softeners of choice in Europe and elsewhere, replacing the imidazolinium and dialkyldimethyl ammonium types. 

The single largest market use for quaternary fatty amines is in fabric softeners. Monoalkyl quaternaries (chloride) have been used in Hquid detergent softener antistat formulations (LDSA), dialkyldimethyl quaternaries (chloride) in the rinse cycle, and dialkyldimethyl quaternaries (sulfate) as dryer softeners. 

Another significant use for dialkyldimethyl quaternary ammonium salts and alkylbenzyldimethylarnmoiiium salts is in preparing organoclays for use as drilling muds, paint thickeners, and lubricants. 

The methyl sulfate dialkyldimethyl quaternaries and ester quaternaries are the cationic surfactants of choice for tumble dryer sheets. The compounds typically used to optimize the softener actives release from the dryer sheet include poly(ethylene glycol) esters and fatty amine soaps. Recent data indicate that through the proper selection of release agent (such as a 4 mol alkoxylate), the melt characteristics of the dryer sheet actives can be optimized to deliver the softener actives more consistently over the entire tumble drying cycle. 

Derivatives Quaternary AMoniun Salts Dialkyldimethyl (Continued) ... 

Applications. The major use of quartemaries is related to their ability to adsorb on natural or synthetic substrates and fibers. Less-soluble long hydrophobic chain containing compounds (e.g., dialkyldimethyl ammonium chlorides) deposit on fibers and... 

N NMR has been demonstrated for differentiation of quaternary amines monoalkyltrimethyl-, dialkyldimethyl-, and tetramethylammonium chlorides gave well-resolved individual peaks (46). 

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