Selective Ring Opening of Methylcyclopentane and Methylcyclohexane Over Iridium Bifunctional Catalysts Supported on Surface Modified γ-Al2O3, SiO2 and Ultra Stable Y Zeolites

Abstract

Selective ring opening of methylcyclopentane (MCP) and methylcyclohexane (MCH) over a series of Iridium catalysts supported on c-alumina, silica and ultrastable Y (USY) zeolites was investigated. The acid density of the supports was modified by co impregnation of potassium in small quantities and its effect on conversion, yield and selectivity was evaluated. USY zeolites showed 26.9-38.1 and 27.5-33.7% of conversion with ring opening selectivities between 56.4-63.8 and 94.3-97.7% for MCP and MCH, respectively. Whereas on silica, the conversions were 10.7-16.6 and 10.4-14.0% with 96.9-99.0 and 93.3-99.1% selectivity. Interestingly, potassium acted as a promoter in case of USY zeolites while suppressed of activity of Ir supported on c-alumina and silica. The reaction conditions such as temperature, pressure, contact time and the feed/catalyst ratio were optimized. The evaluation of catalysts' activity and selectivity towards ring opening of MCP and MCH is of great importance in understanding which catalyst modification could be effective in treatment of gasoline/diesel feed stocks for improving octane/cetane rating and fuel quality.

Upgrading of light cycle oil by partial hydrogenation and selective ring opening over an iridium bifunctional catalyst

“…For this reason, potassium was used as a basic component for tuning the acidic properties of the catalysts in this work. The modified catalysts were investigated previously [16] to find its effect on conversion and selectivity for ring opening products of MCP and MCH (methylcyclohexane) as model compounds. In this study, the best among the modifications was selected for hydrogenolysis of LCO in a batch-type reactor.…”

“…LCO can be used as a diesel component if most of the aromatics are converted into paraffins. On the basis of the preliminary experimental results obtained on MCP as a model compound, 0.75 K/0.9 Ir/USY was selected for treatment of LCO [16]. Thus, hydrogenolysis of LCO over 0.9% Ir/USY catalyst doped with 0.75% K was tried to achieve partial aromatic ring saturation followed by SRO of naphthenes to produce paraffins of the same carbon numbers.…”

Synergism between the Lewis and Brönsted acid sites on HZSM-5 zeolites in the conversion of methylcyclohexane

“…On the other hand, with the rapid growth in the demand for ethene and especially propene, the ring opening and cracking of aromatics with condensed rings also offers a strategy to increase olefin production. MCH has been used as a model reactant to investigate ring opening reactions for many years over various acidic, and mono-and bimetallic catalysts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Selective ring opening (SRO) towards target products is very important for producing either ethene and propene or other hydrocarbons for highly efficient combustion.…”

Catalytic selective ring opening of polyaromatics for cleaner transportation fuels

“…Bifunctional catalysts are thus the best candidates for ring opening of C6 hydrocarbons. 123 Detailed discussions of different catalyst classes and their structure–activity relationships towards MCP and MCH ring opening are presented in Section 4.…”