Versator

VersaCAD Versalink Versamid Versatate VVIO Versatate VV9 Versatic 10... 

Versatic acid Versatic Acids Versa TL Versed... 

Extraction by carboxyUc acids (qv) is carried out in a neutral or weaMy acidic medium. The most widely used carboxyUc acid is RR (CH2)CCOOH, where Rplus represents seven carbon atoms. Trade names are Versatic 10 (Shell Chemicals) and Neodecanoic acid (Exxon Chemicals). CarboxyUc acids can be used either in chloride or in nitrate media and have a better selectivity for light lanthanides than for heavy lanthanide separation. 

Trialkylacetic acids have been produced commercially siace the early 1960s, ia the United States by Exxon and ia Europe by Shell, and have been marketed as neo acids (Exxon) or as Versatic Acids (Shell). The principal commercial products are the acid and the C q acid (neodecanoic acid, or Versatic 10), although smaller quantities of other carbon numbers, such as C, C, and C, are also produced. 

Fig. 2. Flow sheet of Shell Versatic Acid unit (33).

Physical Properties. The C q trialkylacetic acids, referred to as neodecanoic acid [26896-20-8] or as Versatic 10 [52627-73-3] are Hquids at room temperature. Typical physical properties for commercially available material are given in Table 2. These materials are typically mixtures of isomers, hence no stmctures are given throughout this section. 

In the deaeration of high-viscosity fluids such as polymers, the material is flowed in thin sheets along solid surfaces. Vacuum is apphed to increase bubble size and hasten separation. The Versator (Cornell Machine Co.) degasses viscous liquids by spreading them... 

Figure 2. Effect of polymerization temperature (0) and AlR, Nd(vers), molar ratio (O) on molecular weight. Et,Al/ Ndivers), molar ratio was kept at 40 1 when the temperature was varied, and the temperature was maintained at 60°C when Et,Al/Nd(vers), molar ratio was varied. Nd(vers), is the neodymium salt of Versatic 10, which is a mixture of isomeric tertiary carboxylic acids.

Whilst carboxylic acids are readily available and inexpensive, they are relatively weak extractants and have not found much use in the recovery of base metals until recently when Versatic 10 has been piloted for the separation of Ni from Mn and Mg (Section 9.17.5.4). As with the phosphorus(V) acid extractants, the propensity for association leads to substantial levels of solvation of caboxylato... 

The stoichiometry of Versatic 10 Ni extraction has been the subject of much investigation. Distribution data for the extraction of nickel from aqueous solution is consistent with the generalized equilibrium.266 267... 

Preston, J. S. Dupreez, A. C. Synergistic effects in the solvent-extraction of some divalent metals by mixtures of Versatic-10 acid and pyridinecarboxylate esters. J. Chem. Technol. Biotechnol. 1994, 61, 159-165. 

Jaaskelainen, E. Paatero, E. Characterisation of organic phase species in the extraction of nickel by pre-neutralised Versatic 10. Hydrometallurgy 2000, 55, 181-200. 

Jaaskelainen, E. Paatero, E. Extraction of nickel using saponified Versatic 10. Value Adding through Solvent Extraction, [Papers presented at ISEC 96], Melbourne, Mar. 19-23, 1996, 1, 421-426. 

Figure 1.16 Schematic and comparative illustrative of grafting (a) an amorphous silica gel and (b) an ordered MCM-41 silica materials. Entrapment of oxidation catalyst perruthenate inside the channels of MCM-41 silica (below) results in a shape-selective aerobic catalyst, which may not be desirable from the viewpoint of catalyst versatality (Reproduced from ref. 39, with permission.)...

Low-molecular-weight extractants can generally be expected to have uneconomic solubilities in most systems, but where high salt concentrations prevail, the solubility may be substantially lower and may be economic. This has been shown to be true for naphthenic and Versatic acids, which have high solubilities in water but appear to be economically useful when used in high ammonium sulfate liquors, such as those produced in the Sherritt-Gordon process for the extraction of cobalt and separation from nickel [12]. 

The solubility of Versatic 911 in water has been studied as a function of both pH and salt concentration for a fixed (0.5 mol dm ) concentration of reagent in the solvent [15] and is illustrated in Fig. 7.10. The use of high salt concentrations (4moldm ammonium sulfate) has been shown to be effective in keeping Versatic 911 losses at pH 7-8 to more economic levels (<100 ppm) in the separation of cobalt from nickel [16]. 

Fig. 7.10 Solubility of Versatic 911 (O.SOmoldm ) in ammonium sulfate solution. (From Ref. 15.)... 

Problems associated with this flow sheet include cross contamination of the organic phases and aqueous solubility losses of the Versatic acid. 

Both carboxylic (e.g., Versatic acid) and organophosphorus acids have been used commercially to extract the lanthanides. The extraction follows the formation of the metal-extractant complex [Eq. (11.21)] and so depends on the pH of the feed. 

Versatic acid vinyl esters Vinyl ethers N-Vinylpyrrolidone Vinyl chloride Vinylidene chloride Semicrystalline polymers (2)... 

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