Hyamin presence

Turbidimetric titration has also been applied to one-phase titration of alcohol sulfates and other anionic surfactants. The titration is carried out with hyamine 1622 in aqueous solution without the organic phase and indicator and the endpoint is taken as the point of maximum turbidity. The presence of nonionics and inorganic salts at high concentration interfere with the endpoint determination [243]. 

This concept allows the shape of the titration curves to be explained by postulating that the chloroform droplet size decreases as the interfacial tension (ift) between the aqueous and chloroform phases is decreased by the presence of active surfactant. As the endpoint in a titration is approached the amount of active SDBS decreases as it complexes with the injected hyamine. The reduction in the amount of active surfactant material results in an increase... 

Figure 5. The effect of added platinum metal on the hydrolysis of ethyl benzoate in the presence of Hyamine 2389 (4.87 X 10 M. Key , rate in the absence of platinum or surfactant, and O, rate in the presence of platinum and surfactant.

Thorium is one of the few multivalent metals [others are Au(III), Ce(IV), U(VI), and Cr(VI)] which are extractable as nitrate complexes from nitric acid solutions [25-28]. The extractants used include TBP in CCI4 [26,29], TOPO in cyclohexane, toluene or xylene [25,30,31], and triphenylarsine oxide in CHCI3 [27]. Other reagents used for extraction of the nitrate complex of thorium include dibutyl dithiophosphate in various organic solvents [32], dibutyl sulphoxide in xylene [28], and bis(2-butoxyethyl) ether [33].The liquid anion-exchanger Aliquat 336 in xylene [34] and a solution of tertiary ammonium salt (Hyamine) in dichloroethane [35] have been also proposed for extraction of Th. The presence of Li, Na, or A1 nitrate improves the extraction of thorium. Sulphate, phosphate, and tartrate do not interfere, but fluoride must be masked, e.g., by aluminium. Thorium has been separated from U and Pu with the use of Alamine 336 and TOPO (in xylene or cyclohexane) [36]. 

Let us describe the mechanism of two-phase titration in some detail, using the titration of sodium dodecylsulfate (SDS) with Hyamine 1622 in the presence of mixed dye indicator as an example. At the beginning of the titration, when only SDS is present in aqueous solution, dimidium bromide reacts with it to form a salt that is insoluble in water, but... 

It has been observed that liquid scintillators containing p-dioxane or Triton X-100 show chemiluminescence in the presence of a quaternary ammonium base such as Hyamine. This chemiluminescence decays gradually over a long period of time and is probably related to the singlet oxygen ( Ag) generated in situ (Peng, 1976). 

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