2425-77-6Relevant articles and documents
Properties and sodium salicylate induced aggregation behavior of a tail-branched cationic surfactant with a hydroxyl-containing hydrophilic head
Zhang, Yongjie,Li, Yunling,Song, Yongbo,Li, Jun
, p. 105952 - 105960 (2015)
A cationic surfactant with a Guerbet-type branched tail and hydroxyl-decorated head group was synthesized and characterized. Its properties including surface activity, dynamic surface tension, wetting ability, concentration/salt induced aggregation pattern transition and rheological responses of aqueous solutions were measured and analyzed. It was found that this new amphiphile possessed powerful surface activity (γcmc = 25.26 mN m-1) and could enhance the spreading of an aqueous solution on a low energy solid surface (paraffin surface); while dynamic surface tension measurements implied that the diffusion rate of surfactant molecules, influenced by the presence of hydroxyl groups, had an impact on the wetting process. It was determined that the introduction of branching hydrophobes and hydroxyls into the amphiphilic material crucially contributed to the superior performances. Moreover, a visual transition with increasing concentration of its aqueous solution was observed, while the addition of the structure-forming additive sodium salicylate (NaSal) could highly improve the viscosity by inducing the micellar growth in the cationic system which was researched by rheological experiments. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were operated to investigate the transformation of aggregates which are responsible for the concentration/salt induced phase behavior transition or rheological responses.
Dehydrogenative alcohol coupling and one-pot cross metathesis/dehydrogenative coupling reactions of alcohols using Hoveyda-Grubbs catalysts
?zer, Halenur,Arslan, Dilan,?ztürk, Bengi ?zgün
, p. 5992 - 6000 (2021/04/12)
In this study,in situformed ruthenium hydride species that were generated from Grubbs type catalysts are used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of Grubbs first generation catalysts (G1) in dehydrogenative alcohol coupling reactions can be tuned for the ester formation in the presence of weak bases, while the selectivity can be switched to the β-alkylated alcohol formation using strong bases. The performance of Hoveyda-Grubbs 2nd generation catalyst (HG2) was improved in the presence of tricyclohexylphosphine for the selective synthesis of ester derivatives with weak and strong bases in quantitative yields. Allyl alcohol was used as self and cross-metathesis substrate for the HG2 catalyzed sequential cross-metathesis/dehydrogenative alcohol coupling reactions to obtain γ-butyrolactone and long-chain ester derivatives in quantitative yields.
Diastereoselective synthesis of functionally substituted alkene dimers and oligomers, catalysed by chiral zirconocenes
Kovyazin, Pavel V.,Abdullin, Il'giz N.,Parfenova, Lyudmila V.
, p. 144 - 152 (2018/11/21)
The research addresses the reaction of terminal alkenes and propene with AlR3 (R = Me, Et) in the presence of chiral Zr complexes, rac-[Y(η5-C9H10)2]ZrCl2 (Y = C2H4, SiMe2) or (NMI)2ZrCl2 (NMI- η5–neomenthylindenyl), and methylaluminoxane. The effect of reaction conditions, catalyst and trialkylalane structure on the substrate conversion and the reaction chemo- and stereoselectivity has been studied. The reaction predominantly goes via the stage of alkene methyl(ethyl)zirconation with subsequent introduction of substrate molecules into the Zr-C bond. As a result, a diastereoselective one-pot method for the synthesis of functionally substituted linear terminal alkene dimers and propene oligomers was developed.
