DFT Study of Lewis Base Interactions with the MgCl2 Surface in the Ziegler−Natta Catalytic System: Expanding the Role of the Donors

2010 ◽  
Vol 114 (37) ◽  
pp. 15771-15781 ◽  
Author(s):  
Kumar Vanka ◽  
Gurmeet Singh ◽  
Divya Iyer ◽  
Virendra K. Gupta
2020 ◽  
Vol 16 ◽  
Author(s):  
Jean-François Gal ◽  
Pierre-Charles Maria

Background: The ubiquitous Lewis acid/base interactions are important in solution processes. Analytical chemistry may benefit of a better understanding of the role of Lewis basicity, at the molecular level or acting through a bulk solvent effect. Objective: To clearly delineate (i) the basicity at a molecular level, hereafter referred as solute basicity, and (ii) the solvent basicity, which is a bulk-liquid property. Method: The literature that relates Lewis basicity scales and solvent effects is analyzed. A special focus is placed on two extensive scales, the Donor Number, DN, and the BF3 affinity scale, BF3A, which were obtained by calorimetric measurement on molecules as solutes diluted in a quasi-inert solvent, and therefore define a molecular Lewis basicity. We discuss the validity of these solute scales when regarded as solvent scales, in particular when the basicity of strongly associated liquids is discussed. Results: We demonstrate the drawbacks of confusing the Lewis basicity of a solvent molecule, isolated as solute, and that of the bulk liquid solvent itself. Conclusion: Consequently, we recommend a reasoned use of the concept of Lewis basicity taking clearly into account the specificity of the process for which a Lewis basicity effect may be invoked. In particular, the action of the Lewis base, either as an isolated entity, or as a bulk liquid, must be distinguished.


2017 ◽  
Vol 121 (36) ◽  
pp. 19786-19795 ◽  
Author(s):  
Carlos Jimenez-Orozco ◽  
Elizabeth Florez ◽  
Andres Moreno ◽  
Ping Liu ◽  
José A. Rodriguez

2017 ◽  
Vol 19 (36) ◽  
pp. 25105-25114 ◽  
Author(s):  
Akira Oda ◽  
Takahiro Ohkubo ◽  
Takashi Yumura ◽  
Hisayoshi Kobayashi ◽  
Yasushige Kuroda

Understanding the exact position and the detailed role of the Al array in zeolites is essential for elucidating the origin of unique properties and for designing zeolite materials with high efficiency in catalytic and adsorption processes. In this work, we advanced pivotal roles of Lewis base–metal ion bifunctionality caused by Al atoms arrayed circumferentially in the MFI-zeolite pores.


2017 ◽  
Vol 9 (38) ◽  
pp. 32868-32875 ◽  
Author(s):  
Xiaobing Cao ◽  
Lili Zhi ◽  
Yahui Li ◽  
Fei Fang ◽  
Xian Cui ◽  
...  
Keyword(s):  

2015 ◽  
Vol 51 (87) ◽  
pp. 15788-15791 ◽  
Author(s):  
Chandra M. R. Volla ◽  
Eleonora Fava ◽  
Iuliana Atodiresei ◽  
Magnus Rueping

A dual catalytic system consisting of indium triflate and a chiral imidazolidinone catalyzes the asymmetric addition of aldehydes to N-acyl quinoliniums furnishing optically active dihydroquinolines in good yields and excellent selectivities.


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