Ion‐like ethylzinc(II) compounds with weakly coordinating aluminates [Al(ORF)4]? and [(RFO)3Al‐F‐Al(ORF)3]? (RF=C(CF3)3) were synthesized in a one‐pot reaction and fully characterized by single‐crystal X‐ray diffraction, NMR and vibrational spectroscopy, and by quantum chemical calculations. The catalytic activity of ion‐like Et‐Zn[Al(ORF)4] in intermolecular hydroamination and in the unusual double hydroamination of anilines and alkynes was investigated. Favorable performance was also found in comparison to the Et2Zn/ [PhNMe2H]+[B(C6F5)4]? system generated in situ at lower catalyst loadings of 2.5 mol %. 相似文献
Nano‐Zn[2‐boromophenylsalicylaldiminemethylpyranopyrazole]Cl2 (nano‐[Zn‐2BSMP]Cl2) as a novel nanostructured Schiff base complex was prepared and characterized using several techniques. Nano‐[Zn‐2BSMP]Cl2 was used as an effective catalyst for the preparation of some pyrano[2,3‐d]pyrimidinedione derivatives by the multicomponent reaction of malononitrile, aryl aldehydes and barbituric acid derivatives. The novelty and efficiency of nano‐[Zn‐2BSMP]Cl2 as a catalyst, in comparison with some other reported catalysts, for this synthetic transformation are the main features of this work. 相似文献
Preparation of Compounds of the Series C2ClnF6?n with High Fluor Contents by Heterogeneous Catalysis A survey is given on catalytic systems for Cl? F exchange reactions with C2Cl6. A catalyst is described which is formed by reaction of C2Cl4/Cl2/HF on γ-Al2O3 in Ni reactors. Deposition of nickel proceeds by the reaction Ni(CO)4 → Ni + 4 CO. The formation of the catalyst and the catalytic reactions which give highly fluorinated C? Cl? F compounds are discussed. 相似文献
High‐temperature gas‐phase, solvent‐ and catalyst‐free reaction of naphthalene with an excess of RFI reagent (RF?CF3, C2F5, n‐C3F7, and n‐C4F9) was used for the first time to produce a series of highly perfluoroalkylated naphthalene products NAPH(RF)n with n=2–5. Four 95+ % pure 1,3,5,7‐NAPH(RF)4 with RF?CF3, C2F5, n‐C3F7, and n‐C4F9 were isolated using a simple chromatography‐free procedure. These new compounds were fully characterized by 19F and 1H NMR spectroscopy, X‐ray crystallography (for RF?CF3 and C2F5), atmospheric‐pressure chemical ionization mass spectrometry, and cyclic and square‐wave voltammetry. DFT calculations confirm that the proposed synthesis yields the most stable isomers that have not been accessed by alternative preparation techniques. 相似文献
The chlorination of Si−H bonds often requires stoichiometric amounts of metal salts in conjunction with hazardous reagents, such as tin chlorides, Cl2, and CCl4. The catalytic chlorination of silanes often involves the use of expensive transition‐metal catalysts. By a new simple, selective, and highly efficient catalytic metal‐free method for the chlorination of Si−H bonds, mono‐, di‐, and trihydrosilanes were selectively chlorinated in the presence of a catalytic amount of B(C6F5)3 or Et2O⋅B(C6F5)3 and HCl with the release of H2 as a by‐product. The hydrides in di‐ and trihydrosilanes could be selectively chlorinated by HCl in a stepwise manner when Et2O⋅B(C6F5)3 was used as the catalyst. A mechanism is proposed for these catalytic chlorination reactions on the basis of competition experiments and density functional theory (DFT) calculations. 相似文献
Nano‐Zn‐[2‐boromophenyl‐salicylaldimine‐methylpyranopyrazole]Cl2 (nano‐[Zn‐2BSMP]Cl2) as a nanoparticle Schiff base complex and a catalyst was introduced for the solvent‐free synthesis of 4‐((2‐hydroxynaphthalen‐1‐yl)(aryl)methyl)‐5‐methyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐ones by the multicomponent condensation reaction of various aromatic aldehydes, β‐naphthol, ethyl acetoacetate, and phenyl hydrazine at room temperature. 相似文献
A series of Keggin‐type heteropolyacid‐based heterogeneous catalysts (Co‐/Fe‐/Cu‐POM‐octyl‐NH3‐SBA‐15) were synthesized via immobilized transition metal mono‐ substituted phosphotungstic acids (Co‐/Fe‐/Cu‐POM) on octyl‐amino‐co‐functionalized mesoporous silica SBA‐15 (octyl‐NH2‐SBA‐15). Characterization results indicated that Co‐/Fe‐/Cu‐POM units were highly dispersed in mesochannels of SBA‐15, and both types of Brønsted and Lewis acid sites existed in Co‐/Fe‐/Cu‐POM‐octyl‐NH3‐SBA‐15 catalysts. Co‐POM‐octyl‐NH3‐SBA‐15 catalyst showed excellent catalytic performance in H2O2‐mediated cyclohexene epoxidation with 83.8% of cyclohexene conversion, 92.8% of cyclohexene oxide selectivity, and 98/2 of epoxidation/allylic oxidation selectivity. The order of catalytic activity was Co‐POM‐octyl‐NH3‐SBA‐15 > Fe‐POM‐octyl‐NH3‐SBA‐15 > Cu‐POM‐octyl‐NH3‐SBA‐15. In order to obtain insights into the role of ‐octyl moieties during catalysis, an octyl‐free catalyst (Co‐POM‐NH3‐SBA‐15) was also synthesized. In comparison with Co‐POM‐NH3‐SBA‐15, Co‐POM‐octyl‐NH3‐SBA‐15 showed enhanced catalytic properties (viz. activity and selectivity) in cyclohexene epoxidation. Strong chemical bonding between ‐NH3+ anchored on the surface of SBA‐15 and heteropolyanions resulted in excellent stability of Co‐POM‐octyl‐NH3‐SBA‐15 catalyst, and it could be reused six times without considerable loss of activity. 相似文献
A series of SBA‐15‐supported chromia‐ceria catalysts with 3% Cr and 1%–5% Ce (3Cr‐Ce/SBA) were prepared using an incipient wetness impregnation method. The catalysts were characterized by XRD, N2 adsorption, SEM, TEM‐EDX, Raman spectroscopy, UV–vis spectroscopy, XPS and H2‐TPR, and their catalytic performance for isobutane dehydrogenation with CO2 was tested. The addition of ceria to SBA‐15‐supported chromia improves the dispersion of chromium species. 3Cr‐Ce/SBA catalysts are more active than SBA‐15‐supported chromia (3Cr/SBA), which is due to a higher concentration of Cr6+ species present on the former catalysts. The 3Cr‐3Ce/SBA catalyst shows the highest activity, which gives 35.4% isobutane conversion and 89.6% isobutene selectivity at 570 °C after 10 min of the reaction. 相似文献
2‐X‐1, 2‐Difluoroalk‐1‐enylxenon(II) salts were prepared by the reaction of XeF2 with XCF=CFBF2 (X = F, trans‐H, cis‐Cl, trans‐Cl, cis‐CF3, cis‐C2F5) but no organoxenon(II) compounds were obtained when the trans‐isomers of boranes, trans‐XCF=CFBF2 (X = CF3, C4F9, C4H9, Et3Si), were used under similar conditions. 相似文献
In this work, a series of novel acidic polymerized ionic liquids were used as heterogeneous catalyst for alkylation of o‐Xylene with styrene. And the effect of the amount of initiator and the type of acid used for ion exchange on catalyst structure and the catalytic performance of catalysts for alkylation were studied thoroughly. The experiment results show: when the percentage of the amount of initiator in the total material is 3%, the polymerized ionic liquid catalyst MPM‐SO3H‐[C3V][SO3CF3] has the most uniform with a specific surface area of 97.30 m2/g and a pore volume of 0.35 cm3/g. Benefiting from the unique structure features, MPM‐SO3H‐[C3V][SO3CF3] manifested an excellent catalytic performance for alkylation of o‐Xylene with styrene, along with the conversion of styrene was 96.8% and the yield of 1‐Phenyl‐1‐ortho‐xylene ethane was 94.7%. Therefore, this work provides a novel reference to the synthesis of polymerized ionic liquids and clearly explains the advantage of novel acidic polymerized ionic liquids on alkylation. 相似文献
Liquid phase hydrogenolysis of ethyl lactate to 1,2‐propanediol was performed over silica supporting cobalt catalysts prepared by two different methods: precipitation‐gel (PG) technique and deposition‐precipitation (DP) procedure. The cobalt species (Co3O4/cobalt phyllosilicate) present in the corresponding calcined PG and DP catalysts were different as a consequence of the preparation methods, and Co OH Co olation and Si O Co oxolation molecular mechanisms were employed to elucidate the chemical phenomena during the different preparation procedures. In addition, the texture (BET), reduction behavior (TPR and in‐situ XRD), surface dispersion and state of cobalt species (XPS), and catalytic performance differ greatly between the samples. Because of small particle size, high dispersion of cobalt species and facile reducibility, the Co/SiO2 catalyst prepared by precipitation‐gel method presented a much higher activity than the catalyst prepared by deposition‐precipitation method. Metallic cobalt is assumed to be the catalytically active site for the hydrogenolysis reaction according to the catalytic results of both cobalt samples reduced at different temperatures and the structure changes after reaction. 相似文献
Phosphinic acids, RfP(O)(OH)H (Rf=CF3, C2F5, C6F5), turned out to be excellent preligands for the coordination of phosphonous acids, RfP(OH)2. Addition of C2F5P(O)(OH)H to solid PtCl2 under different reaction conditions allows the isolation and full characterization of the mononuclear complexes [ClPt{P(C2F5)(OH)O}{P(C2F5)(OH)2}2] and [Pt{P(C2F5)(OH)O}2{P(C2F5)(OH)2}] containing hydrogen‐bridged [RfP(OH)O]? and RfP(OH)2 units. Further deprotonation of [Pt{P(C2F5)(OH)O}2{P(C2F5)(OH)2}2] leads to the formation of the dianionic platinate, [Pt{P(C2F5)(OH)O}4]2?, revealing four intramolecular hydrogen bridges. With PdCl2 the dinuclear complex [Pd2(μ‐Cl)2{[P(C2F5)(OH)O]2H}2] was isolated and characterized. The Cl? free complex [Pd{P(C2F5)(OH)O}2{P(C2F5)(OH)2}2] was also prepared and deprotonated to the dianionic palladate, [Pd{P(C2F5)(OH)O}4]2?. Both compounds were characterized by NMR spectroscopy, IR spectroscopy, and X‐ray analyses. In addition, the C6F5 derivatives [ClPt{P(C6F5)(OH)O}{P(C6F5)(OH)2}2] and [Pd2(μ‐Cl)2{[P(C6F5)(OH)O]2H}2] as well as the CF3 derivative [Pd2(μ‐Cl)2{[P(CF3)(OH)O]2H}2] were synthesized and fully characterized. Phosphonous acid complexes are inert towards air and moisture and can be stored for several months without decomposition. The catalytic activity of the palladium complexes in the Suzuki cross‐coupling reaction between 1‐bromo‐3‐fluorobenzene and phenyl boronic acid was demonstrated. 相似文献
Two C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups (─CF3), Ni{PhC(O)CHC[N(9‐fluorenyl)]CF2}2 (Ni 1 ) and Ni{CF3C(O)CHC[N(9‐fluorenyl)]Ph}2 (Ni 2 ), were synthesized by metal coordination reaction and different in situ bonding mechanisms. The C–C bridged bonds of Ni 1 were formed by in situ intramolecular trifluoromethyl and 9‐fluorenyl carbon–carbon cross‐coupling reaction and those of Ni 2 were formed by in situ intramolecular 9‐fluorenyl carbon–carbon radical coupling reaction mechanism. The obtained complexes were characterized using 1H NMR spectroscopy and elemental analyses. The crystal and molecular structures of Ni 1 and Ni 2 with C–C bridged configuration were determined using X‐ray diffraction. Ni 1 and Ni 2 were used as catalysts for norbornene (NB) polymerization after activation with B(C6F5)3 and the catalytic activities reached 106 gpolymer molNi?1 h?1. The copolymerization of NB and styrene catalyzed by the Ni 1 /B(C6F5)3 system showed high activity (105 gpolymer molNi?1 h?1) and the catalytic activities decreased with increasing feed content of styrene. All vinyl‐type copolymers exhibited high molecular weight (104 g mol?1), narrow molecular weight distribution (Mw/Mn = 1.71–2.80), high styrene insertion ratios (11.13–50.81%) and high thermal stability (Td > 380°C) and could be made into thin films with high transparency in the visible region (400–800 nm). 相似文献
Summary: Treatment of Zr{3‐But‐2‐(O)C6H3CHN(C6F5)}Cl3(THF) with K[2‐(C6H5NCH)C4H3N] yields Zr{3‐But‐2‐(O)C6H3CHN(C6F5)}{2‐(C6H5NCH)C4H3N}Cl2, the first example of a (salicylaldiminato)(pyrrolylaldiminato)zirconium complex. The catalytic behavior of both the new zirconium pre‐catalyst and its titanium analogue have been determined. The titanium system is the more effective catalyst for both ethene homopolymerization and copolymerizations with hex‐1‐ene, norbornene, and cyclopentene. The titanium catalyst combines the high productivities of the bis(salicylaldiminato) parent complex with the more favorable comonomer incorporation of the bis(pyrrolylaldiminato) series.
Copolymerizations with pre‐catalysts 1 and 2 . 相似文献
Gaseous fluorination with hydrogen fluoride at atmospheric pressure of the two isomers CClF2-CClF2 and CF3-CCl2F was continuously carried out on a chromic oxide based catalyst. The fluorinated derivative, obtained at a selectivity higher than 90%, was pentafluorochloroethane. Hexafluoroethane and an isomeric mixture of trichlorotrifluoroethanes were obtained as byproducts. The latter were recycled to fluorination together with unconverted C2Cl2F4. Both conversion of C2Cl2F4 and selectivity to C2ClF5 were affected by temperature, contact time and molar ratio of the reagents.The catalytic activity of chromic oxide was adversely affected by small amounts of water in the hydrogen fluoride. A difference in reactivity between the two isomers CF3-CCl2F and CClF2-CClF2 was also observed.It was also observed that the byproduction of C2Cl3F3 was due to the disproportionating activity of obromic oxide versus C2Cl2F4. 相似文献