Oxidative Methylation of Toluene with Methane over Basic Zeolite Catalysts Promoted with Alkali Metal Bromides and Alkali Metal Oxides

IntroductionStyrene is one of the most important industrial monomers. At present, styrene is mainlyproduced by alkylation of benzene with ethylene followed by oxidative dehydrogenationof the resulting ethylbenzene. However, this process is very expensive and complex. Anew method of synthesizing ethylbenzene and styrene directly from toluene and methanewas discovered by Khcheyan el al. ', and Yakovich and Bakareva2. The process wouldpotentially reduce the cost because of the production of sty…     

The first one-pot synthesis of alkoxycyclopropanes via cyclometalation of styrene with ClnAlEt3−n and RCO2R′ mediated by Cp2ZrCl2

The one-pot cyclopropanation of styrene using Cl_nAlEt_3−n (Et₂AlCl, EtAlCl₂, AlCl₃) and carboxylic esters in the presence of Cp₂ZrCl₂ as catalyst gives rise to alkoxycyclopropanes.     

The vinylarene Diels-Alder reaction,development and potential

The report covers the vinylarene Diels-Alder reaction including the use of styrene as the diene component reacted with activated alkynes or alkenes as dienophiles. The development of the process includes thermal conditions together with recent base, Lewis acid, and microwave irradiation promotion conditions. Mechanistic insights from deuterated substrates and DFT calculations indicate a concerted asynchronous [4 + 2] cycloaddition followed by a step-wise 1,3-hydrogen transfer step to restore aromaticity. Total synthesis and materials applications are also included.     

Microemulsion polymerization of styrene stabilized by sodium dodecyl sulfate and diethylene glycol monoalkyl ether

The effects of the cosurfactants diethylene glycol monoalkyl ether [C _i H_{2 i +1}O(CH₂CH₂O) _j OH (C _i E _j ; i=4, 6 and j=1, 2)] on the formation of an oil-in-water styrene (ST) microemulsion and the subsequent free radical polymerization were studied. For comparison, the data for the C _i H_{2 i +1}OH (C _i OH; i=4, 6) systems obtained from the literature were also included in this work. Sodium dodecyl sulfate was used as the surfactant. The pseudo three-component phase diagram (macroemulsion, microemulsion and lamellar gel phases) was constructed for each cosurfactant. The primary parameters selected for the polymerization study are the concentrations of cosurfactant and styrene. The number of latex particles nucleated is much smaller than that of the microemulsion droplets initially present in the reaction system. Limited flocculation of the latex particles occurs to some extent during polymerization. Among the cosurfactants investigated, the C₄OH-containing polymerization system is the least stable. By contrast, the diethylene glycol monoalkyl ether group of C _i E _j tends to enhance the latex stability. C _i E _j is more effective in stabilizing the ST microemulsion and the subsequent polymerization in comparison with the C _i OH counterpart. Received: 24 December 1999 Accepted: 9 February 2000     

SO_4~(2-)/ZrO_2-TiO_2-SiO_2固体酸催化苯乙烯选择氧化反应的研究

制备了一种 SO2 -4 促进的金属氧化物固体酸 SO2 -4 / Zr O2 - Ti O2 - Si O2 ,并将其用于催化C6H5C2 H3的选择氧化反应 ,发现该新型固体酸具有较高的活性和选择性 ,C6H5C2 H3转化率达 1 0 .73% ,C6H5C2 H3O选择性达 2 0 .73%。随着 Ti含量的增大 ,催化活性提高 ;用共沉淀法比用浸渍法能更有效地在固体酸中形成选择氧化活性结构。用 IR,XRD等方法进行的表征表明 ,反应的选择氧化活性位可能含有 Zr,Si,O,Ti等成分。     

聚四氟乙烯微粉辐照接枝苯乙烯的XPS研究

聚四氟乙烯微粉辐照接枝苯乙烯的ＸＰＳ研究许观藩，罗云霞，杨弘（中国科学院长春应用化学研究所，长春，１３００２２）关键词聚四氟乙烯，苯乙烯，表面接枝，ＸＰＳ用辐照方法在疏水性高聚物材料表面接枝聚合亲水性单体，可以达到改性的目的．文献中所用的高聚物材料包...     

Styrene polymerization using nickel(II) complexes as catalysts

Styrene polymerization is investigated with neutral and cationic Ni(II) complexes, i.e. Ni(bipy)Me₂, 1, Ni(bipy)Br₂, 2, Ni(phen)Br₂, 3, or Ni(Me₂phen)Br₂, 4, Ni(acac)₂, 5, (bipy = 2,2′-bipyridine, phen = phenanthroline, Me₂phen = 2,9-dimethyl-1,10-phenanthroline, acac = acetylacetonate), activated by [NHMe₂Ph][B(C₆F₅)₄] or B(C₆F₅)₃ as cocatalysts, in the presence of AlMe₃. The influence on the polystyrene features and the reaction kinetics of the nickel complex and boron activator, the Al/Ni or B/Ni molar ratios as well as the monomer concentration are studied. Catalytic systems derived from 2, 3 or 5 and [NHMe₂Ph][B(C₆F₅)₄] at a Ni:B:Al ratio of 1:1:5 are the most efficient at room temperature.     

The surface properties of ionomers based on styrene-co-acrylic acid copolymers

The surface properties of styrene-co-acrylic acid copolymers and of the obtained ionomers containing alkali metal ions, before and after UV-irradiation, were investigated by the measurements of water contact angles and ATR-FTIR spectroscopy.It was examined, how the content and nature of the alkali metal introduced into the initial copolymer influences the water contact angle, surface free energy and its components, polar and dispersive.It was ascertained that the water contact angle, surface free energy and its components depend on the content of introduced acid or salt. These values were practically independent of the nature of the alkali metal introduced into the copolymer. However, more considerable changes were observed for the ionomers containing sodium ions.The research has indicated that UV-irradiation causes the increase in surface hydrophilicity of the investigated ionomers.