Development of realistic models for Double Metal Cyanide catalyst active sites.

نویسندگان

  • Jacek C Wojdeł
  • Stefan T Bromley
  • Francesc Illas
  • Jacobus C Jansen
چکیده

Realistic molecular models of one and two-centre catalytic active sites originating from the cleavage of a precursor material known to give rise to an active double metal cyanide catalyst are described. Via periodic density functional calculations the structure of the proposed catalytic sites are shown to be dependent on electrostatic and structural relaxation processes occurring at the surfaces of the precursor material. It is shown how these effects may be adequately captured by small molecular models of the active sites. The general methodology proposed should provide a computationally efficient basis for detailed future studies into catalytic reactions over double metal cyanide materials.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Two-dimensional double metal cyanide complexes: highly active catalysts for the homopolymerization of propylene oxide and copolymerization of propylene oxide and carbon dioxide.

The synthesis of two-dimensional double metal cyanide complexes of the formula Co(H2O)2[M(CN)4].4H2O (M=Ni, Pd or Pt) and the X-ray crystal structure of Co(H2O)2[Pd(CN)4].4H2O are presented. The anhydrous forms of these complexes were found to be effective catalyst precursors for the homopolymerization of propylene oxide as well as the random copolymerization of propylene oxide and carbon dioxi...

متن کامل

Complex Dynamic Behavior during Polyol Preparation in Continuous Processes Using Heterogeneous Double Metal Cyanide Catalysts

The transition from batch to continuous processes for polyol production presents interesting challenges because of the unusual behavior of double metal cyanide (DMC) catalysts. One feature that is often observed in these catalysts is the need for an activation period whose length changes from one catalyst formulation to another. When this activation occurs in the same reactor where the chain gr...

متن کامل

The Effect of Alkali Metal Promoters on the Stability and Coke Formation of Platinum-Based Propane Dehydrogenation Catalysts: A Kinetic Study

The kinetics of catalyst deactivation and coke formation during dehydrogenation of propane over supported Pt–based catalysts and, in particular, the effect of alkali metal promoters on catalyst activity and stability were studied. The analysis of propane conversion data showed that there is an optimum level of alkali metal promoter loading for both catalyst activity and stability.A model ba...

متن کامل

Brønsted acidic ionic liquid as a metal free catalyst for the one-pot synthesis of α-aminonitriles under mild and solvent-free conditions

An efficient, mild and environmentally friendly method was developed for the Strecker reaction to synthesize α-aminonitriles in the presence of methyl imidazolium hydrogen sulfate ([Hmim][HSO4]) as an efficient catalyst. These syntheses were performed via a one-pot three-component condensation of aldehydes (or ketones), amines, and trimethylsilyl cyanide under mild and solvent free c...

متن کامل

Effects of Temperature and Cocatalyst Concentration on the Number of Active Sites in a TiCl4/Mg(OEt)2 Catalyst for Ethylene Polymerization

The slurry polymerization of ethylene was studied by employing a (TiCl4/Mg(OEt)2/TEA) catalyst system in hexane. The effects of triethylaluminum concentration and temperature on polymer yield and polymer viscosity average molecular weight, Mv, were investigated. The maximum polymer yield was obtained at an Al/Ti molar ratio of 124. The highest yield and Mv were achieved at 60 °C. The concentrat...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of molecular modeling

دوره 13 6-7  شماره 

صفحات  -

تاریخ انتشار 2007