Ruthenium Catalysts Templated on Mesoporous MCM-41 Type Silica and Natural Clay Nanotubes for Hydrogenation of Benzene to Cyclohexane

Aleksandr Glotov,Valentine Stytsenko,Aleksey Pimerzin,Anna Vutolkina,Vladimir Vinokurov,Eduard Karakhanov,Vladimir Nedolivko,Gleb Zasypalov

doi:10.3390/catal10050537

Abstract

Mesoporous ruthenium catalysts (0.74–3.06 wt%) based on ordered Mobil Composition of Matter No. 41 (MCM-41) silica arrays on aluminosilicate halloysite nanotubes (HNTs), as well as HNT-based counterparts, were synthesized and tested in benzene hydrogenation. The structure of HNT core-shell silica composite-supported Ru catalysts were investigated by transmission electron microscopy (TEM), X-ray fluorescence (XRF) and temperature-programmed reduction (TPR-H2). The textural characteristics were specified by low-temperature nitrogen adsorption/desorption. The catalytic evaluation of Ru nanoparticles supported on both the pristine HNTs and MCM-41/HNT composite in benzene hydrogenation was carried out in a Parr multiple reactor system with batch stirred reactors (autoclaves) at 80 °C, a hydrogen pressure of 3.0 MPa and a hydrogen/benzene molar ratio of 3.3. Due to its hierarchical structure and high specific surface area, the MCM-41/HNT composite provided the uniform distribution and stabilization of Ru nanoparticles (NPs) resulted in the higher specific activity and stability as compared with the HNT-based counterpart. The highest specific activity (5594 h−1) along with deep benzene hydrogenation to cyclohexane was achieved for the Ru/MCM-41/HNT catalyst with a low metal content.

Highlights

In the modern global quest for cleaner fuel production, benzene has been identified as a gasoline component that should be reduced
The structure of the well ordered mesoporous MCM-41 type silica assembled on the outer surface of halloysite nanotubes (HNTs), retained after Ru loading, was clearly indicated by transmission electron microscopy (TEM) (Figure 1)
Mesoporous ruthenium catalysts (0.74–3.06 wt%), based on ordered MCM-41 silica arrays on aluminosilicate halloysite nanotubes (HNTs), as well as HNT-based counterparts, were synthesized and tested in benzene hydrogenation

Summary

Introduction

In the modern global quest for cleaner fuel production, benzene has been identified as a gasoline component that should be reduced. According to the modern clean fuel standard regulations in the US, Mobil Source Air Toxics II (MSAT II), refiners are required to reduce benzene in gasoline to. There are two main strategies for benzene hydrogenation: partial hydrogenation aimed to cyclohexene production and deep hydrogenation to cyclohexane [4,5,6,7]. The former often requires bimetallic systems as catalysts, such as Ru–Zn, Ru–Co, Ru–Cu and Ru–lanthanides, promoted by various additives or non-promoted [4,7,8,9].

Methods

Results

Conclusion