A potential pentaerythritol-based bio-lubricants from 10-undecylenic acid: Its physico-chemical assessment

In this study, renewable, non-toxic, sulphur free bio-lubricants are synthesized as alternative for fossil fuels. We utilized a bio-derived 10-undecylenic acid (UDA) and pentaerythritol (PE) as raw materials to synthesize bio-lubricants by two-step chemical processes like esterification and followed by epoxidation reactions. And achieved a UDA-PE epoxide yielded 73.4%. The formation of UDA-PE ester and UDA-PE epoxide was confirmed by spectral analysis such as NMR (¹H and ¹³C), FTIR and mass spectra, Physico-chemical and basic lubricant properties by standard American Society for Testing and Materials methods (ASTM). The results showed that the products of UDA-PE ester and UDA-PE epoxide had high viscosity index (262 and 200), good pour points (−29 °C to −15 °C), high flash points (296 °C and 301 °C) respectively and these met the ISO VG (International Organization for Standardization-Viscosity grade) 22 and 220 standard values. In general, both synthesized products are plausible to be employed as bio-lubricant in industrial application.     

Novel 10-I-3 hypervalent iodine-based compounds for electrophilic trifluoromethylation

The synthesis of a new family of 10-I-3 hypervalent iodine compounds is described in which the CF3 functionality participates directly in the hypervalent bond. These materials are accessible by nucleophilic ligand substitution at iodine using Me3SiCF3 in the presence of a substoichiometric amount of fluoride. The expected T-shaped geometry at iodine was verified by X-ray crystallographic analyses of three of the products (1-trifluoromethyl-1,2-benziodoxol-3-(1 H)-one and two substituted 1-trifluoromethyl-1,3-dihydro-1,2-benziodoxoles). Preliminary results for the direct electrophilic transfer of the trifluoromethyl moiety onto organic nucleophiles show modest reactivity in polar aprotic solvents under relatively mild conditions. The overall process can be understood as a formal umpolung of the CF3 group.     

Reactivity of a 10-I-3 hypervalent iodine trifluoromethylation reagent with phenols

The reaction of the 10-I-3 hypervalent iodine electrophilic trifluoromethylation reagent 1-trifluoromethyl-1,2-benziodoxol-3-(1H)-one (2) with 2,4,6-trimethylphenol, after deprotonation with NaH and in the presence of 18-crown-6 in a polar, nonprotic solvent, affords 1,3,5-trimethyl-2-(trifluoromethoxy)benzene (4) only as a byproduct. Trifluoromethylation occurs preferentially at the ortho- and para-positions of the aromatic core, giving the corresponding trifluoromethylcyclohexadienones 5 and 6. In case the ortho- and/or para-positions are not substituted, the corresponding products of an aromatic, electrophilic substitution are obtained in moderate yield, for example, 2-trifluoromethyl-4-tert-butylphenol (10a) from 4-tert-butylphenol (10).     

Anodic dissolution of osmium in acid media

The anodic dissolution of Os in acidic solutions was studied under potentiostatic conditions. The results show high dissolution rates that increase markedly at rising potential. The presence of chloride ions and to a greater extent the increase in acidity of the solutions inhibit the anodic corrosion process. The nature of the dissolution products did depend on the solution pH and the concentration of the complexing anion. Thus, in HClO₄ acid and in chloride solutions at low concentration or acidity, Os goes into solution as OsO₄; in concentrated HCl solution, tetraoxide and chloro-osmyl anions are formed. No OsCl₆^2? complex was detected in solution even at high HCl concentration.     

Nucleophilic trifluoromethylation of arylidenemalononitriles

A method for the nucleophilic trifluoromethylation of arylidenemalononitriles using Me₃SiCF₃ is described. The reaction is carried out in dimethylformamide in the presence of AcONa as a Lewis base, and affords products of Michael addition in high yield.     

Thermolytic trifluoromethylation of pentafluoropyridine

Russian Chemical Bulletin -     

Towards enantioselective nucleophilic trifluoromethylation

Various trifluoroacetamides and trifluoromethanesulfinamides, derived from chiral silylated amino alcohols, have been synthesized with the goal of achieving enantioselective nucleophilic trifluoromethylation. The best results were obtained with (R)-phenylglycinol derivatives, but the ee values did not exceed 30 %.     

Radical trifluoromethylation of ammonium enolates

The easy radical trifluoromethylation of a series of 1,3-dicarbonyl compounds with CF₃I is described. The reaction occurs in the presence of a nitrogen base and sodium dithionite in CH₃CN-H₂O solution. Additionally, we report a new access to ammonium triflinates.     

Electrophilic trifluoromethylation of S-hydrogen phosphorothioates

A series of S-hydrogen phosphorothioates have been converted to the corresponding S-trifluoromethyl derivatives upon reaction with the electrophilic trifluoromethylation reagent 1 (trifluoromethyl 1,3-dihydro-3,3-dimethyl-1,2-benziodoxole). Relative rate data were obtained by (19)F NMR monitoring of competition experiments and were evaluated by means of the Taft equation. A high positive polar sensitivity factor of 2.55 was found for electron-rich substrates and a negative one of -0.37 for electron-poor ones, implying the involvement of two different rate-determining steps. Furthermore, the reaction was found to be unaffected by steric factors.     

Electrochemical trifluoromethylation of aromatic compounds

It was shown that the current yield of the products of anodic trifluoromethylation of arenes correlates with the adsorptivity and the rate of electrooxidation of arenes on the surface of a platinum electrode. Translated fromIzvestiya Akademi Nauk, Seriya Khimicheskaya, No. 6, pp. 1180–1184, June, 1997.     

Anodic dissolution of cobalt suicides in sulfuric acid solutions

Anodic dissolution of suicides Co₂Si, CoSi, and CoSi₂ in 0.5 M H₂SO₄ solutions with and without NaF is studied by polarization methods coupled with an atomic-absorption analysis. In the absence of NaF, anodic stability of cobalt silicides is higher than that of cobalt itself by 3–6 orders of magnitude and increases in the series Co₂Si < CoSi < CoSi₂. Cobalt selectively dissolves from the lattice of silicides, while silicon simultaneously oxidizes to SiO₂. The process is controlled by the diffusion of elemental and oxidized cobalt in the suicide and the SiO₂ surface layer, respectively. The anodic dissolution rate of silicides markedly increases in the presence of NaF, while their anodic stability becomes less different.     

Radical trifluoromethylation of ketone Li enolates

It has generally been believed that highly basic Li enolates cannot be applied as substrates for radical trifluoromethylation due to defluorination of the α-CF₃ product. However, Li enolates can be in fact employed for radical trifluoromethylation. Moreover, the reaction is extremely fast and the minimum reaction time is only ∼1 s.