Naphthenates, lanthanide

Oil field uses are primarily imidazolines for surfactant and corrosion inhibition (see Petroleum). Besides the lubrication market for metal salts, the miscellaneous market is comprised of free acids used ia concrete additives, motor oil lubricants, and asphalt-paving applications (47) (see Asphalt Lubrication AND lubricants). Naphthenic acid has also been studied ia ore flotation for recovery of rare-earth metals (48) (see Flotation Lanthanides). 

Sc(naphthenate)3/ROH/AlR3 (1/2/7) has been found to exhibit an activity similar to the lanthanide series catalyst [114], The cis PA film obtained with it showed an electrical conductivity of 14.4 S cm 1 when the polymer was doped with I2 at a ratio of (CHI0.04)n, and the TEM measurement suggested the formation of ca. 20-30 nm fibrils. 

The lanthanides find some use as stabilizers for polymers. The coating of polycarbonate with a poly(vinyl alcohol) film containing CeCl3 inhibits photodegradation of the polycarbonate.151 The naphthenates of cerium, lanthanum and yttrium act as thermal stabilizers for polyorgano-siloxanes.152... 

The high activity of Nd-based catalysts was reported by Shen et al. in 1980 [92], In this publication, the polymerization activity of the whole lanthanide series was studied. Ln halogen-based binary catalyst systems (LnCb/EtOH/AlEts or LnCl3 (TBPU/Al Bua), as well as Ln-carboxylate-based ternary catalyst systems (Ln(naphthenate)3/AlIBu3/EASC) were used. The activity profile for the entire series of lanthanides is depicted in Fig. 2. Two years later, Monakov et al. confirmed in a similar study that Nd is the most active Ln element [93,94]. 

C2H5)(CH2)3CH3), naphthenate (CnH10O2), versatate, etc.) and AlEt2Cl in solution, followed by addition of Al(i-Bu)3 [32]. The lanthanides commonly used are Nd, Gd, Ce, and Pr, in which the Nd catalysts exhibit higher activity than the other metal catalysts (Eq. 8). The catalysts,... 

Preston (1985) described the solvent extraction behavior of a large number of metal cations including rare earth nitrates in solutions of Versatic 10 (2-ethyl-2-methylheptanoic acid), naphthenic, 2-bromodecanoic and 3,5-diisopropylsalicylic acids in xylene. The last two acids extract metal cations under more acidic conditions, pH 1-2. For Versatic 10 the order of extraction of yttrium and lanthanides is La < Ce < Nd < Gd < Y < Ho < Yb and for naphthenic acids it is La < Ce < Y < Nd < Gd k Ho Yb. The lanthanides tend to form complexes of predominantly ionic nature. In the case of Versatic 10, the stability of the complexes increases uniformly with atomic number due to the increase in electrostatic energy as a result of the decrease in ionic radius. The primary branched naphthenic acid allows the formation of complexes with high coordination number, nine for La to Nd, eight and eventually six as the metal ionic radius decreases. In general, the extraction of a metal ion by a carboxylic acid H2A2 can be represented by the reaction... 

---