Effect of Cosolvent in a Nucleophilic Substitution Reaction Using Organoclay in Triphase Catalytic System

Nahid Shabestary,Thao T Doan,Sadegh Khazaeli,Cynthia M Chapple,Michael J Sabo,Derek T Rensing,Andrew D Beach

doi:10.4236/mrc.2015.43010

Nahid Shabestary, Thao T Doan + Show 5 more

Open Access

https://doi.org/10.4236/mrc.2015.43010

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Abstract

A remarkable rate enhancement technique has been devised for a typical nucleophilic displacement reaction by using triphase catalytic materials based on tetraoctylammonium exchange forms of hectorite clay. Pseudo-first order rate constants (kobs) for the conversion of 1-bromobutane to the corresponding chloride under triphase conditions using the clay catalyst in the presence of various polar cosolvents have been observed. The results here have shown that the addition of a cosolvent increases the catalytic activity of the triphase system by several fold. In addition, the results have demonstrated that each cosolvent has a unique concentration for achieving an optimum reaction rate.

Highlights

Triphase catalysis (TC) has been introduced as a unique type of heterogeneous catalysis in which the catalyst and each of a pair of reactants are located in different phases [1]-[7]
An aliquot of 1% aqueous suspension of hectorite clay was added to an aliquot of aqueous solution of tetraoctylammonium bromide surfactant with a concentration twice that of the clay cation exchange capacity (CEC) to ensure that all the interlayer sodium cations were replaced by tetraoctylammonium ions
A significant catalytic activity enhancement has been observed in a triphase catalytic system by using a cosolvent

Summary

Introduction

Triphase catalysis (TC) has been introduced as a unique type of heterogeneous catalysis in which the catalyst and each of a pair of reactants are located in different phases [1]-[7]. In a triphase system (Figure 1), the reactants from two immiscible liquid phases (usually water and organic solvent, such as toluene) are transferred to the solid interface where they react and make product. Based on this type of heterogeneous catalysis, numerous synthetic routes have been developed for aqueous-. The polymer supported triphase catalysts have not yet found industrial applications due to their high cost and stability problems Other solid supports such as oxides, zeolites and clays have been explored by various investigators [13]-[18]. We have demonstrated a significant reaction rate enhancement through application of various polar cosolvents in organoclay triphase catalytic system

Chemicals and Instruments

Hectorite Clay Intercalation Reaction

Triphase Catalytic Reaction

Results and Discussion

Conclusion