108-57-6Relevant academic research and scientific papers
Nickel-Catalyzed Reductive Cross-Coupling of Aryl Bromides with Vinyl Acetate in Dimethyl Isosorbide as a Sustainable Solvent
Huang, Xia,Jin, Jian,Lei, Chuanhu,Su, Mincong
supporting information, (2022/01/15)
A nickel-catalyzed reductive cross-coupling has been achieved using (hetero)aryl bromides and vinyl acetate as the coupling partners. This mild, applicable method provides a reliable access to a variety of vinyl arenes, heteroarenes, and benzoheterocycles, which should expand the chemical space of precursors to fine chemicals and polymers. Importantly, a sustainable solvent, dimethyl isosorbide, is used, making this protocol more attractive from the point of view of green chemistry.
Phosphonium Phenolate Zwitterion vs Phosphonium Ylide: Synthesis, Characterization and Reactivity Study of a Trimethylphosphonium Phenolate Zwitterion
Xiao, Jing,Li, Qiang,Shen, Ruwei,Shimada, Shigeru,Han, Li-Biao
supporting information, p. 5715 - 5720 (2019/11/22)
4-Methoxy-3-(trimethylphosphonio)phenolate was obtained from a regioselective addition of PMe3 to p-quinone monoacetal. This compound undergoes hydrogen isotope exchange with D2O or CD3CN, and is capable of catalyzing H/D exchange of CD3CN with substrates bearing weakly acidic hydrogens. It exhibits similar reactivity to phosphorus ylides for olefinations of aldehydes. A possible tautomerization between the phosphonium phenolate zwitterion and phosphonium ylide is proposed for the first time to rationalize the unique reactivity.
Copper-Catalyzed Oxidative Difunctionalization of Terminal Unactivated Alkenes
Hussain, Muhammad Ijaz,Feng, Yangyang,Hu, Liangzhen,Deng, Qingfu,Zhang, Xiaohui,Xiong, Yan
, p. 7852 - 7859 (2018/05/30)
The copper(II)-promoted free-radical oxidative difunctionalization of terminal alkenes to access ketoazides by utilizing molecular oxygen has been reported. A series of styrene derivatives have been evaluated and were found to be compatible to give the desired difunctionalized products in moderate to good yields. The role of molecular oxygen both as an oxidant and oxygen atom source in this catalytic transformation has been unquestionably demonstrated by 18O-labeling studies and a radical mechanistic pathway involving the oxidative formation of azidyl radicals is also designed. This environment-friendly catalytic oxidative protocol can transform aldehyde to nitrile.
Practical Photocatalytic Trifluoromethylation and Hydrotrifluoromethylation of Styrenes in Batch and Flow
Straathof, Natan J. W.,Cramer, Sten E.,Hessel, Volker,No?l, Timothy
supporting information, p. 15549 - 15553 (2016/12/09)
Styrenes represent a challenging class of substrates for current radical trifluoromethylation and hydrotrifluoromethylation methods due to a myriad of potential side reactions. Herein, we describe the development of mild, selective and broadly applicable photocatalytic trifluoromethylation and hydrotrifluoromethylation protocols for these challenging substrates. The methods use fac-Ir(ppy)3, visible light and inexpensive CF3I and can be applied to a diverse set of vinylarene substrates. The use of continuous-flow photochemical reaction conditions allowed to reduce the reaction time and increase the reaction selectivity.
Supported palladium nanoparticles as heterogeneous ligand-free catalysts for the Hiyama C-C coupling of vinylsilanes and halobenzenes leading to styrenes
Grirrane, Abdessamad,Garcia, Hermenegildo,Corma, Avelino
, p. 49 - 57 (2013/06/27)
The Hiyama C-C coupling reaction of a wide range of aryl iodides and vinylsilanes has been performed using ligand-free solid catalysts based on supported palladium nanoparticles. Among the supports tested (Mg, TiO 2, CeO2 and active carbon), the most active catalysts were those in which palladium is supported on MgO and TiO2. Analogous Pt and Au materials were inefficient to promote this reaction. Leaching tests suggest that there is some contribution of dissolved Pd since Pd in solution has been detected and the scavenging test decreases the initial reaction rate. Although the solid Pd catalysts can be reused, it was, however, observed that they undergo a certain deactivation upon use that can be attributed to several factors including the presence of inorganic compounds on the catalyst, Pd leaching or agglomeration of Pd NPs.
Living anionic polymerization of 1,4-divinylbenzene and its isomers
Tanaka, Shunsuke,Matsumoto, Masayoshi,Goseki, Raita,Ishizone, Takashi,Hirao, Akira
, p. 146 - 154 (2013/03/14)
The anionic polymerization of 1,4-divinylbenzene (1) and its ortho (2) and meta isomers (3) were studied under a variety of conditions. One of the two vinyl groups of 1 was selectively and exclusively polymerized in a living manner by the addition of a suitable additive under the conditions of -78 C for 1 min and -95 C for 30 min. Under such conditions, the unwanted addition reaction of the chain-end anion to the pendant vinyl group was almost suppressed and soluble polymers with predictable molecular weights of up to 60 500 g/mol and narrow molecular weight distributions (Mw/Mn 1.05) were quantitatively obtained. The amount of dimerized chain produced by the addition reaction was negligible or very small (5%). The effective additives in the polymerization involve potassium alkoxides and phenoxides, derived from tert-butyl alcohol, sec-butyl alcohol, 2,4-dimethyl-3-pentanol, 1-methylcyclohexanol, 1:2,5:6-di-O-isopropylidene-α-d-glucofuranose, phenol, 1-naphthol, and 2,6-di(tert-butyl)-4-methylphenol, and potassium carboxylate derived from pivalic acid. The living polymer of 1 was not stable at -78 C after 5 min or longer times, but very stable at -95 C even for 30 min. The chain-end anion could be stabilized by end-capping with tert-butyl methacrylate and 1,1-diphenylethylene, and the resulting anions remained unchanged at -78 C even after several hours.
Catalytic chain transfer mediated autopolymerization of divinylbenzene: Toward facile synthesis of high alkene functional group density hyperbranched materials
Barker, Ian A.,El Harfi, Jaouad,Adlington, Kevin,Howdle, Steven M.,Irvine, Derek J.
, p. 9258 - 9266 (2013/03/14)
A facile and highly reproducible autopolymerization method, mediated by catalytic chain transfer, for the synthesis of hyperbranched materials with high alkene functional group density is reported. The rapid autopolymerization of divinylbenzene at 150 °C in the absence of any catalytic chain transfer agent was demonstrated to result in the formation of highly cross-linked networks/gels in less than 10 min. Exploitation of the extremely high chain transfer coefficient of bis[(difluoroboryl)diphenylglyoximato]cobalt(II) delayed gelation and produced good yields of high molecular weight hyperbranched divinylbenzene in under 1 h on a multigram scale. Gas chromatography was employed to monitor the levels of conversion over the course of the reaction. The materials produced were characterized by GPC, MALLS, and viscometry.
Gold nanoparticle-catalyzed environmentally benign deoxygenation of epoxides to alkenes
Noujima, Akifumi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
scheme or table, p. 8209 - 8227 (2011/12/14)
We have developed a highly efficient and green catalytic deoxygenation of epoxides to alkenes using gold nanoparticles (NPs) supported on hydrotalcite [HT: Mg6Al2CO3(OH)16] (Au/HT) with alcohols, CO/H2O or H2 as the reducing reagent. Various epoxides were selectively converted to the corresponding alkenes. Among the novel metal NPs on HT, Au/HT was found to exhibit outstanding catalytic activity for the deoxygenation reaction. Moreover, Au/HT can be separated from the reaction mixture and reused with retention of its catalytic activity and selectivity. The high catalytic performance of Au/HT was attributed to the selective formation of Au-hydride species by the cooperative effect between Au NPs and HT.
Room-temperature deoxygenation of epoxides with CO catalyzed by hydrotalcite-supported gold nanoparticles in water
Mitsudome, Takato,Noujima, Akifumi,Mikami, Yusuke,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
experimental part, p. 11818 - 11821 (2011/01/12)
Epoxide deoxygenation: Hydrotalcite-supported gold nanoparticles (Au/HT) efficiently catalyze the deoxygenation of epoxides to alkenes in water at room temperature under CO at atmospheric pressure and in the absence of organic solvents (see graphic). Moreover, Au/HT retains its activity and selectivity and can be reused.
Semivolatile and volatile compounds in combustion of polyethylene
Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
, p. 615 - 627 (2007/10/03)
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
