Alkyl chain length

Fig. IV-24. Effect of alkyl chain length of n-alcohols on the resistance of water evaporation at 25°C. (From Ref. 275.)...

Using guest fluorophores, they show that the adsorption energy increases linearly with the alkyl chain length as... 

Reaction of 57 with dihalogenoalkanes is reported to give not only the expected dithioether (58) but also the bicyclic salt (59) (Scheme 26) (118). This reaction should depend on the alkyl chain length. 

The effect of an o>-phenyl group as a function of the alkyl chain length has been studied in 3-(through-space interaction has been evidenced on the reactivity of the thiocarbonyl group. 

Wetting times of /V,/V-dimethy1-/ -alkyl amine oxides as a function of the alkyl chain length show a minimum with dimethyl dodecyl amine oxide (Table 3). Foam generation of dimethyl-/ -alkylamine oxides solutions show a maximum when the alkyl group contains 14 carbons. 

Amine oxide CAS Registry Number Alkyl chain length Wetting time, s Foam height, mm... 

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]. 

Alk l chain. The increase in the alkyl chain length and linearity improves the efficiency of the plasticizer and the low-temperature flexibility of the plasticized polymers. 

Other examples include ditholium salts, shown in Figure 4.1-8 [30]. The scattering data show that a range of mesophase behavior is present, dependent - as with the metal-containing systems - on alkyl chain length. 

The charged species were in all cases found to concentrate at the surface of the liquid under vacuum conditions. Little surface separation of the anions and cations was observed. For the [PFg] and [BFJ ions, the cation ring was found to prefer a perpendicular orientation to the surface, with the nitrogen atoms closest to the surface. An increase in the alkyl chain length caused the cation to rotate so that the alkyl chain moved into the bulk liquid, away from the surface, forcing the methyl group closer to the surface. For halide ionic liquids, the data were less clear and the cation could be fitted to a number of orientations. 

The aliphatic mononitriles may not show molecular ions, but M - 1, M - 27, or M - 28 are usually observed. Sometimes a loss of 15 Daltons may also be observed. If CH3 is replaced by CF3, as in the case of CF3CH2CH2CN, a fluorine is first lost from the molecular ion, followed by the loss of HCN (from the M -F ion). This influence of the CF3 group diminishes as the alkyl chain length increases. 

Alkylbenzenes have molecular ions at the following m/z values 92, 106, 120, 148, and so forth. The molecular ion intensity decreases with increasing alkyl chain length, but can be detected up to at least Cifi. Characteristic fragment ions are m/z 39, 50, 51, 52, 63, 65, 76, 77, and 91. 

A distinct dependence between LAS alkyl chain length and the chronic or long-term toxicity is also shown (see Table 22) [290,291]. As can be seen, the ecotoxicity of LAS for fishes and daphnia increase significantly with increasing alkyl chain length of the LAS homolog. 

Because of its superior solubility characteristics, a high 2-phenyl LAS (with an alkyl chain length average of 11.4) was the preferred type. The detergency performance of one LAS/AE type of formulation was discussed previously (see Figs. 12 and 13). Early commercial heavy-duty liquid (HDL) formulations were built with phosphate, but since 1979 almost all U.S. HDLs have been formulated without phosphate. 

The various olefinsulfonates used in this study differed in their alkyl chain lengths and in the position of the ionic head group along the hydrophobe moiety. Furthermore, the composition of some IOS compounds was modulated by using different process conditions. 

The alkyl chain length of the starting olefin is 18. by-Hydroxyalkanesulfonate. cp -Hydroxyalkanesulfonate. dSee text. 

Sodium a-sulfonated fatty acid esters of long-chain alcohols have a structural effect on the Krafft point different from that of amphiphiles with short alkyl chains [60]. In a series of homologs with the same total carbon number the Krafft points are highest when the hydrophilic alkyl chain lengths in the a-sulfonated fatty acid and the alcohol are fairly long and equal. In this case the packing of the molecules becomes close and tight. 

The effect of surfactant structures and properties on emulsion polymerization have been investigated by numerous authors [82-89]. Efforts were made to study the effects of surfactants with different molecular weights on the rate of polymerization [82], swelling and solubilization effects [83], effects of alkyl chain length of homologous series on the rate of polymerization, particle size... 

In the case of N-containing phosphonates some interesting data were observed [190]. Alkanephosphonic acid bisdiethanolamides, RPO(NCH2CH2OH)2, show good wetting performance and foamability at an alkyl chain length of C,0 and C12 according to Table 10. 

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