Applied Petrochemical Research (v.8, #1)
Comparative investigation on radical polymerization of methyl and ethyl methacrylate under multi-site phase-transfer catalytic conditions by Vajjiravel Murugesan; Elumalai Marimuthu (1-11).
Methyl and ethyl methacrylate was polymerized in heterogeneous system with the help of newly synthesized multi-site phase-transfer catalyst and using water-soluble initiator at 60 ± 1 °C under unstirred inert atmospheric condition. Polymer yield was increased with increasing molar concentrations of monomer, initiator, catalyst and temperature. Polymerization follows first-order kinetics with respect to monomer and half-order with respect to catalyst and initiator, respectively. PTC has myriads of applications in the synthesis of various organic and polymeric materials because of its fast reaction and high yield in short period of time. Without addition of PTC, polymerization did not occur; this indicates that catalyst plays the pivotal role on initiation of polymerization. It extracts the reactive radical anion from aqueous phase and transfers to the organic phase where acrylates were polymerized. Polymerization reactivity of methyl and ethyl methacrylate under PTC conditions was studied by various parameters. The activation energy (Ea) and other thermodynamic parameters were calculated. The Ea value supports the reactivity of acrylates. The results obtained from this investigation were used for inferring the radical mechanism of phase-transfer-catalyzed polymerization. The obtained polymers were analyzed by spectral and thermal analyses.
Keywords: Kinetics; Multi-site phase-transfer catalyst; Rate of polymerization; Two-phase system; Methyl and ethyl methacrylate
Synthesis of SAPO-34 catalysts via sonochemically prepared method and its catalytic performance in methanol conversion to light olefins by Rana Ahmadova; Hikmet Ibragimov; Evgenii Kondratenko; Uwe Rodemerc (13-20).
Methanol-to-olefin (MTO) reaction was investigated over sonochemically (SAPO-34-U40, SAPO-34-U70, SAPO-34-U100) and hydrothermally (SAPO-34-HT) prepared nanocatalysts. The catalytic performance of prepared samples was investigated over all samples at 450 °C and over SAPO-34-U40 at 350–450 °C temperature range. The higher yield ~ 97 wt% (31.4 wt% C2=, 49.4 wt% C3= and 16.1 wt% sumC4=) of light olefins was obtained at 375 °C on SAPO-34-U40. Physico-chemical properties of catalysts were characterized by XRD, SEM, BET, ICP techniques. XRD analysis showed suitable crystalline structure and SEM images confirmed perfect crystallinity of sonochemically prepared samples. BET analysis indicated remarkable surface area of SAPO-34-U40. The amount of carbon deposits and character of coke was determined by TPO analysis. The higher amount of coke was determined over SAPO-34-HT in comparison to another’s at 450 °C. The character of coke deposited over SAPO-34-U40 was similar for 375–425 °C temperatures.
Keywords: SAPO-34; Ultrasound; Hydrothermal; Nanocatalyst; Catalytic performance; MTO
An experimental investigation on effective parameters of batch impregnation systems: a case study on Pt–Sn/Al2O3 catalyst by Maryam Takht Ravanchi; Shokoufeh Mehrazma; Saeed Sahebdelfar (21-27).
The adsorption of hexachloroplatinic acid on Sn-impregnated γ-alumina support in the presence of the competitive chloride ion, as a step in preparation of multi-metallic Pt-based catalyst (such as Pt–Sn/Al2O3), was studied. The transient adsorption data were obtained by studying the impregnation of Sn/Al2O3 with H2PtCl6 in an external recycle packed-bed impregnation system. The effect of important parameters such as pH of the impregnating solution, circulation flow rate, and height/diameter ratio of support bed on competitive adsorption was studied. It was observed that upon increasing pH and decreasing circulation rate, the rate of Pt adsorption as well as axial non-uniformity along the bed was increased. On the other hand, a time lag was observed in bulk adsorbate concentration in certain runs which was attributed to deviation from well-mixed contacting pattern being necessary for a uniform catalyst product. This could be minimized by increasing the recycling flow rates and using appropriate amounts of competitive ion concentration.
Keywords: Pt–Sn/Al2O3 ; Catalyst synthesis; Wet impregnation; Competitive adsorption; Recycle reactor
Reaction kinetics of ethane partial oxidation to acetic acid by Sulaiman I. Al-Mayman; Moustafa A. Soliman; Abdulrahman S. Al-Awadi; Yousef S. Al-Zeghayer (29-38).
The partial oxidation of ethane to ethylene and acetic acid on supported MoVNbPd/TiO2 (P25 of Degussa) has been investigated. Pd was added in a nano-metallic form. The catalyst composition was also different from similar studied catalysts. This results in a better selectivity towards acetic acid formation. The reaction was carried out in a tubular reactor at temperature range 225–275 °C, total pressure range 0–200 psig and oxygen percentage in the feed gas of 10–40%. The feed gas contains ethane and oxygen. In this work, we develop a kinetic model for the reaction for the developed catalyst. In this model, we assume that oxidation reactions take place on different sites; ethane oxidation takes place on one site, ethylene oxidation on another site, and CO is oxidized to CO2 on a third site. The model exhibits good agreement with the experimental data.
Keywords: Ethane; Ethylene; Acetic acid; Partial oxidation; MoVNbPd catalyst
Response surface models for synthetic jet fuel properties by R. L. J. Coetzer; T. S. Joubert; C. L. Viljoen; R. J. J. Nel; C. A. Strydom (39-53).
Jet fuel is a mixture of different hydrocarbon groups, and the mass contribution of each of these groups toward the overall chemical composition of the fuel dictates the bulk physical properties of the fuel after completion of the refining and blending processes. The fluidity properties of jet fuel mixtures at low temperatures are critical in understanding and mitigating the safety risks and performance attributes of aircraft engines, which may lead to the introduction of more stringent specification limits in the near future. Therefore, in this study the low-temperature viscosity and freeze point properties of jet fuels were investigated by variation of the linear to branched chain paraffin mass ratio, in conjunction with variation of the carbon number distribution according to a mixture by process variables experimental design. Furthermore, response surface models were developed and discussed for the two main fluidity properties of interest and inferences were made from the models for the potential generation of optimal jet fuel mixtures.
Keywords: Freeze point; Mixture experimental designs; Response surface models; Synthetic jet fuel; Viscosity