3944-37-4Relevant articles and documents
Cross-linked poly(N-vinylpyrrolidone)-titanium tetrachloride complex: A novel stable solid TiCl4 equivalent as a recyclable polymeric Lewis acid catalyst for regioselective ring-opening alcoholysis of epoxides
Rahmatpour, Ali,Sajjadinezhad, Seyed Mehrzad
, (2021/08/09)
Cross-linked poly(N-vinylpyrrolidone) resin beads were prepared as macromolecular ligand precursors by suspension copolymerization of N-vinyl-2-pyrrolidone and N,N′-methylenebisacrylamide (MBA) as a crosslinking agent in water. Subsequently, the resulting polymer carrier precursor was readily combined with titanium tetrachloride to form a stable polymeric coordination complex (PNVP/TiCl4), and this novel stable TiCl4 equivalent evaluated as a heterogeneous and reusable solid Lewis acid catalyst for the regio-and stereoselective nucleophilic ring opening of various epoxides with various alcohols to prepare β-alkoxy alcohols in excellent yields without generating any waste. The MBA-cross-linked PNVP and resultant catalyst were characterized by Fourier transform infrared spectroscopy (FT–IR), field-emission scanning electron microscope (FE–SEM), energy dispersive X-ray (EDX), inductively coupled plasma (ICP), and thermogravimetric analysis (TGA) techniques. Moreover, the catalyst is very stable, easily separated, and reused at least five times without significant loss of activity. In terms of scope, yields, the amount of catalyst used, and reaction time, the PNVP-TiCl4 complex catalyst is an improvement over previously reported heterogeneous catalysts for ring opening of epoxides methods. Further, the experimental outcome revealed that using the copolymer beads as carriers with a high percentage of crosslinking and the high mesh size leads had an adverse effect on the reaction rate.
Bio-based solvents and gasoline components from renewable 2,3-butanediol and 1,2-propanediol: Synthesis and characterization
Bermeshev, Maxim,Goncharova, Arina,Kniazeva, Mariia,Kosyakov, Dmitry,Ladesov, Anton,Maximov, Anton,Ni, Denis,Samoilov, Vadim,Zarezin, Danil
, (2020/04/17)
In this study approaches for chemical conversions of the renewable compounds 1,2-propanediol (1,2-PD) and 2,3-butanediol (2,3-BD) that yield the corresponding cyclic ketals and glycol ethers have been investigated experimentally. The characterization of the obtained products as potential green solvents and gasoline components is discussed. Cyclic ketals have been obtained by the direct reaction of the diols with lower aliphatic ketones (1,2-PD + acetone→ 2,2,4-trimethyl-1,3-dioxolane (TMD) and 2,3-BD + butanone-2→2-ethyl-2,4,5-trimethyl-1,3-dioxolane (ETMD)), for which the ΔH0 r, ΔS0 r and ΔG0 r values have been estimated experimentally. The monoethers of diols could be obtained through either hydrogenolysis of the pure ketals or from the ketone and the diol via reductive alkylation. In the both reactions, the cyclic ketals (TMD and ETMD) have been hydrogenated in nearly quantitative yields to the corresponding isopropoxypropanols (IPP) and 3-sec-butoxy-2-butanol (SBB) under mild conditions (T = 120-140 °C, p(H2) = 40 bar) with high selectivity (>93%). Four products (TMD, ETMD, IPP and SBB) have been characterized as far as their physical properties are concerned (density, melting/boiling points, viscosity, calorific value, evaporation rate, Antoine equation coe°Cients), as well as their solvent ones (Kamlet-Taft solvatochromic parameters, miscibility, and polymer solubilization). In the investigation of gasoline blending properties, TMD, ETMD, IPP and SBB have shown remarkable antiknock performance with blending antiknock indices of 95.2, 92.7, 99.2 and 99.7 points, respectively.
The Use of Proton-exchanged X-Type Zeolite in Catalysing Ring-opening Reactions of 2-Substituted Epoxides with Nucleophiles and its Effect on Regioselectivity
Takeuchi, Hiroshi,Kitajima, Kunio,Yamamoto, Yasuhiro,Mizuno, Kiyokazu
, p. 199 - 203 (2007/10/02)
The use of proton-exchanged X-type zeolite in catalysing ring-opening reactions of 2-alkyl substituted epoxides with nucleophiles gives a high regioselectivity and functional-selective catalysis giving allylic products from allylic nucleophiles.Mechanistic aspects are discussed.