Chemical Reaction Characteristics of HDTMA+ Cations in Interlayer Space of Vermiculite Crystal Layers

2010 ◽  
Vol 96 ◽  
pp. 15-20 ◽  
Author(s):  
Tong Jiang Peng ◽  
Hong Juan Sun ◽  
Jin Mei Sun ◽  
Hai Feng Liu
Keyword(s):  
Reaction Mechanism ◽  
Chemical Reaction ◽  
Interlayer Space ◽  
Organic Cations ◽  
Reaction Characteristics ◽  
Interstratified Mineral

Hydrophlogopite, a regular interstratified mineral with 1:1 ratio of vermiculite and phlogopite crystal layers, was modified with sodium and organically intercalated with HDTMAB, and then the samples were examined with XRD. Based on the theoretical geometric dimensions of organic cations, the structure and arrangement model of HDTMA+ cation in the interlayer space of vermiculite crystal layers were studied, the reaction mechanism of organic intercalation was also discussed. The results show that HDTMA+ cations enter into the interlayer space of vermiculite crystal layers only without exchange with the cations in the interlayer space of phlogopite crystal layers, and that the arrangement models of HDTMA+ cations in the interlayer space of vermiculite crystal layers varies with the added amount of HDTMAB. When the added amount is small, the arrangement model of HDTMA+ cations in the interlayer space of vermiculite crystal layers is lateral-bilayer, and when the added amount is larger, the arrangement model is paraffin-type monolayer.

A Paramedic Treatment for Modeling Explicitly Solvated Chemical Reaction Mechanisms

2018 ◽  
Author(s):  
Yasemin Basdogan ◽  
John Keith
Keyword(s):  
Reaction Mechanism ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Reaction Pathway ◽  
Optimization Procedure ◽  
Cost Effective ◽  
Chemical Reaction Mechanisms ◽  
Solvent Molecules ◽  
Dynamics Simulations ◽  
Mbh Reaction

<div> <div> <div> <p>We report a static quantum chemistry modeling treatment to study how solvent molecules affect chemical reaction mechanisms without dynamics simulations. This modeling scheme uses a global optimization procedure to identify low energy intermediate states with different numbers of explicit solvent molecules and then the growing string method to locate sequential transition states along a reaction pathway. Testing this approach on the acid-catalyzed Morita-Baylis-Hillman (MBH) reaction in methanol, we found a reaction mechanism that is consistent with both recent experiments and computationally intensive dynamics simulations with explicit solvation. In doing so, we explain unphysical pitfalls that obfuscate computational modeling that uses microsolvated reaction intermediates. This new paramedic approach can promisingly capture essential physical chemistry of the complicated and multistep MBH reaction mechanism, and the energy profiles found with this model appear reasonably insensitive to the level of theory used for energy calculations. Thus, it should be a useful and computationally cost-effective approach for modeling solvent mediated reaction mechanisms when dynamics simulations are not possible. </p> </div> </div> </div>

scholarly journals Experimental validation of the reaction mechanism models of dechlorination and [Zn] reclaiming in the roasting steelmaking zinc-rich dust process

2020 ◽  
Vol 39 (1) ◽  
pp. 107-116
Author(s):  
Hongyang Wang ◽  
Kai Dong ◽  
Rong Zhu
Keyword(s):  
Reaction Mechanism ◽  
Dust Particle ◽  
Chemical Reaction ◽  
Reaction Mechanisms ◽  
Experimental Validation ◽  
Step Process ◽  
Mass Percent ◽  
Mechanism Model ◽  
Air Atmosphere ◽  
Almost All

AbstractThe reaction mechanism models of dechlorination and [Zn] reclaiming in the roasting steelmaking zincrich dust process are studied. The dust collected from a steelwork contains 63.8% zinc and 3.18% chlorine (mass percent), of which, almost all zinc elements exist in ZnO and ZnCl2 forms, and all the chlorine elements are stored in ZnCl2. When the dust is roasted at above 732∘C in an air atmosphere, the ZnCl2 in the steelmaking zinc-rich dust is volatilized into steam and then oxidized into ZnO. Finding the position where the chemical reaction occurs is the key to determining the reaction mechanisms of dechlorination and [Zn] reclaiming. In this study, two groups of thermal experiments are designed and executed for roasting in different atmosphere environments and at different roasting temperatures. Based on the experiment results, the mechanism model is discussed and built, and the reaction of dechlorination and [Zn] reclaiming is shown to be a multi-step process. Because O2 from the air cannot transmit into the dust particle interior or dust bed effectively, the chemical reaction of [Zn] reclaiming occurs in the external gas environment outside of the dust, where the [Zn] recalcining reaction should be limited by the dynamics of new nucleation of ZnO solids.

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