Search for: methanol
Total 167 records
Aluminum solvate complexes forming in acidic methanol-acetone mixtures studied by 27Al NMR spectroscopy, Article Journal of Solution Chemistry ; Volume 38, Issue 2 , 2009 , Pages 159-169 ; 00959782 (ISSN) ; Pourali, S. M ; Tafazzoli, M ; Sharif University of Technology
27Al NMR spectroscopy is a powerful tool for the study of coordination and solvation in both aqueous and nonaqueous solutions. In this study, the complexes coexisting upon dissolution of AlCl3 in acidic acetone + methanol solutions are shown to consist essentially of mixed hexacoordinated species of the general formula [Al(CH3OH) 6-n (CH3COCH3) n ]3+ (n=1,2 and 3), all exhibiting distinctly different 27Al shielding effects. The relative populations of the various mixed species are found to be highly dependent upon the acetone:methanol mole ratio that in the more acetone-rich mixtures with aluminum become appreciably coordinated by acetone. The results demonstrate that the key factor for the...
Article Electrochimica Acta ; Volume 49, Issue 27 , 2004 , Pages 4999-5006 ; 00134686 (ISSN) ; Jafarian, M ; Mahjani, M. G ; Gobal, F ; Sharif University of Technology
Elsevier Ltd 2004
The electro-oxidation of methanol on copper in alkaline solutions has been studied by the methods of cyclic voltammetry, quasi-steady state polarization and chronoamperometry. It has been found that in the course of an anodic potential sweep the electro-oxidation of methanol follows the formation of CuIII and is catalysed by this species through a mediated electron transfer mechanism. The reaction also continues in the early stages of the reversed cycle until it is stopped by the prohibitively negative potentials. The process is diffusion controlled and the current-time responses follow Cottrellian behavior. The rate constants, turnover frequency, anodic transfer coefficient and the apparent...
Photocatalytic conversion of methane into methanol over the MoO 3(010) surface using a simulation method, Article Surface Review and Letters ; Volume 11, Issue 1 , 2004 , Pages 33-39 ; 0218625X (ISSN) ; Dashti, M ; Sharif University of Technology
In this investigation, we have studied the kinetics and mechanism of photocatalytic conversion of methane into methanol reaction over the MoO 3(010) surface using a computer simulation method. Methane and oxygen as the reactants are used at room temperature and atmospheric pressure under UV photoirradiation of the catalyst. According to our data analysis, the order of methanol formation reaction with respect to CH4 and O 2 was determined to be l = 0.30 and m = -1.03, respectively. The highest methanol formation rate (TOF) value was obtained at about 0.05 molecule/s.site in a range of 25-35 W/cm2 incident light intensity with energy hv ≥ Eg. The selectivity of CH3OH was increased with...
Investigation of carbon monoxide tolerance of platinum nanoparticles in the presence of optimum ratio of doped polyaniline with para toluene sulfonic acid and their utilization in a real passive direct methanol fuel cell, Article Electrochimica Acta ; Volume 97 , 2013 , Pages 216-225 ; 00134686 (ISSN) ; Amani, M ; Pahlavanzadeh, H ; Kazemeini, M ; Sharif University of Technology
Polyaniline fiber (PANI) was synthesized by chemical interfacial method and doped with para toluene sulfonic acid (PTSA) through a sequential doping-dedoping-redoping process resulting in PANI-PTSA. The doped material was utilized to fabricate Vulcan-polyaniline composite of C-PANI-PTSA. Next, through reduction, Pt particles were deposited on to this composite to produce a Pt/C-PANI-PTSA electrocatalyst. To investigate the PANI-PTSA interaction with the carbon support as well as, to consider its effect upon the catalytic activity of Pt/C-PANI-PTSA, electrocatalysts with different ratios of 10, 15, 20, 25 and 30 wt% were synthesized and their activity was compared with the Pt/C (Electrochem)....
Article Petroleum Science and Technology ; Vol. 32, Issue. 11 , 2014 , Pages 1349-1356 ; ISSN: 10916466 ; Kazemeini, M ; Asadi, M ; Fattahi, M ; Sharif University of Technology
Methanol conversion was investigated on dealuminated mordenite (DM) as well as a series of promoted DM (i.e., metal/DM) catalysts prepared by impregnation. Prepared catalysts characterized by the powder XRD, BET, and NH3-TPD techniques. Chemical analysis was performed using induced coupled plasma (ICP) method. The conversion of methanol over different metal/mordenite catalysts was compared at 460C and WHSV of 1 h-1. Several metals including Fe, La, and Ca had been used to prepare metal/DM catalysts, which displayed high selectivity toward propylene production. Ultimately, La/DM catalyst was determined to be the best material amongst those investigated for methanol conversion based upon its...
Article Joint 2002 CSCE/ASCE International Conference on Environmetal Engineering - An International Perspective on Enviromental Engineering, Niagara Falls, Ont., 21 July 2002 through 24 July 2002 ; 2002 , Pages 1289-1304 ; 088955532X (ISBN) ; Lawrence, G. A ; Maloney, K ; Sharif University of Technology
This paper describes the results of a study of potential environmental impacts of methanol releases into rivers. A number of hypothetical scenarios are defined, and dispersion of methanol in the selected rivers is investigated using a riverine dispersion-biodegradation model. The downstream variability of river flow and hydraulic geometry due to merging tributaries are included in the model. The model results are presented, and comparison is made with proposed allowable concentrations. An interesting finding is that the river variation has considerable effect on concentration distribution of methanol in the most critical scenario. A sensitivity analysis is made on the key modeling parameters...
Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 30, Issue 5 , 2006 , Pages 595-606 ; 03601307 (ISSN) ; Rahimi, N ; Eftekhari, A. A ; Nasr, M. J ; Sharif University of Technology
The reaction kinetics and chemical equilibrium of the reversible catalytic hydrolysis reaction of a methyl acetate to acetic acid and methanol using a strongly acidic ion exchange resin catalyst named Amberlyst 15 were studied. To investigate the different behavior of Amberlyst 15 in the adsorption of reactants and product species, the equilibrium behavior of binary non-reactive liquid mixtures, consisting of one reactant and one product were studied experimentally. The Langmuir model was used to describe the equilibrium condition, quantitatively. Then the employed model was compared with the more complicated thermodynamic models to describe the equilibrium between the catalytic polymer...
Article Journal of Applied Electrochemistry ; Volume 36, Issue 8 , 2006 , Pages 913-918 ; 0021891X (ISSN) ; Moghaddam, R. B ; Mahjani, M. G ; Gobal, F ; Sharif University of Technology
The electro-catalytic oxidation of methanol on a Ni-Cu alloy (NCA) with atomic ratio of 60/40 having previously undergone 50 potential sweep cycles in the range 0-600 mV vs. (Ag/AgCl) in 1 m NaOH was studied by cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (EIS). The electro-oxidation was observed as large anodic peaks both in the anodic and early stages of the cathodic direction of potential sweep around 420 mV vs. (Ag/AgCl). The electro-catalytic surface was at least an order of magnitude superior to a pure nickel electrode for methanol oxidation. The diffusion coefficient and apparent rate constant of methanol oxidation were found to be 2.16 × 10-4 cm2 s-1 and...
Multi-objective optimisation of steam methane reforming considering stoichiometric ratio indicator for methanol production, Article Journal of Cleaner Production ; Volume 180 , 2018 , Pages 655-665 ; 09596526 (ISSN) ; Iranshahi, D ; Saeidi, S ; Pourazadi, E ; Klemeš, J. J ; Sharif University of Technology
Elsevier Ltd 2018
This work proposes a novel configuration for steam methane reformers (SMR) in order to improve their syngas stoichiometric ratio (SR). This is a decisive element for methanol producers to increase their production tonnage. While the optimum theoretical SR value is around 2, many conventional SMRs operate far beyond this value due to thermodynamic equilibrium limitations. In the new SMR design CO2, which could be an industrial off gas, is injected into the reactor in multiple stages. The corresponding CO2 injection flow rate is determined by a multi-objective optimization method. The optimum flow rate at each stage is chosen to minimise abs (SR-2) while maintaining the CH4 conversion at its...
Article Journal of Industrial and Engineering Chemistry ; Volume 19, Issue 3 , May , 2013 , Pages 915-919 ; 1226086X (ISSN) ; Kazemeini, M ; Mohammadrezaee, A ; Golhosseini, R ; Sharif University of Technology
The effects of i-butane addition to methanol in MTP reaction were investigated over an in-house prepared HZSM-5 catalyst. It was observed that, propylene yield would be enhanced when i-butane fed to the reactor along with methanol. The rising growth of the propylene yield continued to peak on till the balance in thermal condition established. Similar trends have been observed when water was added to the mixture. The effect of WHSV with fixed water composition on product distribution was also studied. The optimum point where the highest amount of propylene yielded was shown to be high depended upon the temperature and residence time
A study on the effect of SiO2/Al2O3 ratio on the structure and performance of nano-sized ZSM-5 in methanol to propylene conversion, Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 121, Issue 2 , 2017 , Pages 763-772 ; 18785190 (ISSN) ; Abbasi, A ; Zargarnezhad, H ; Riazifar, M ; Sharif University of Technology
The effect of SiO2/Al2O3 ratio on high silica content nano-sized HZSM-5 stability and selectivity in conversion of methanol to propylene (MTP) has been investigated in a continuous flow isotherm fixed-bed reactor. Highly crystalline HZSM-5 zeolite samples with SiO2/Al2O3 ratios ranging 150–200 have been prepared and characterized using XRD, ICP-AES analytical techniques, NH3-TPD, BET surface area and SEM imaging for studying their physical and chemical behavior. The reaction was conducted at 480 °C and 1bar with WHSV = 1 h−1 and a solution with 1:1 wt% of methanol and water as feed. Over thoroughly monitoring the catalyst synthesis conditions, the nanocrystal ZSM-5 zeolite samples were...
Study of Cationic Impregnation Method on Zeolite Catalyst for Upgrading of Methanol to Gasoline (MTG)Process, Ph.D. Dissertation Sharif University of Technology ; Ghanbari, Bahram
In the present research, the conversion of methanol to hydrocarbons was studied over a new series of mesoporous low-silica HZSM-5 (Si/Al=11) catalysts impregnated with cations such as Fe, Zn, Mo and Cr. A systematic study on the effect of stepwise modification of the catalysts for the conversion of methanol to gasoline (MTG) was undertaken in a fixed-bed tubular reactor under ambient pressure at 375 °C, feeding with weight hourly space velocity (WHSV) of 2 h−1. The catalysts were prepared in the absence and presence of cationic promoted factors, in both alkaline and neutral aqueous solutions. The final catalysts characterized by using Fourier-transform infrared, X-ray diffraction, X-ray...
Synthesis of highly porous nanocrystalline alumina as a robust catalyst for dehydration of methanol to dimethyl ether, Article Journal of Porous Materials ; Volume 20, Issue 1 , 2013 , Pages 151-157 ; 13802224 (ISSN) ; Kazemeini, M ; Aghaziarati, M ; Alamolhoda, S ; Sharif University of Technology
Highly porous nanocrystalline alumina was synthesized using two different precipitation processes and precipitating agents, which were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosimetry analyses. Different precipitating agents yielded nanocrystalline alumina catalysts with different morphologies and textural properties. Batch precipitation using sodium bicarbonate at constant pH resulted in a highly porous nanocrystalline γ-alumina catalyst, having surface area of 351.47 m2 g-1, total pore volume of 1.68 cm3 g -1 and mean pore diameter of 19.17 nm. The mean crystallite size was also determined to be 3.8 nm, based on the XRD results. Catalytic...
Fourier transform infrared spectroscopy and scanning tunneling spectroscopy of porous silicon in the presence of methanol, Article Sensors and Actuators, B: Chemical ; Volume 132, Issue 1 , 2008 , Pages 40-44 ; 09254005 (ISSN) ; Rahimi, F ; Iraji zad, A ; Sharif University of Technology
Porous silicon samples were obtained from p+- and n-type silicon wafers. Gas sensing measurements showed that the electrical conductivity of porous Si on p+- and n-type wafers increases strongly and decreases weakly in the presence of methanol gas, respectively. Scanning tunneling spectroscopy (STS) indicates that the adsorption of methanol on the surface of n-porous silicon decreases the average density of states especially in the band gap. Fourier transform infrared (FTIR) spectroscopy reveals that after methanol exposure partial surface oxidation occurs which produces electron traps as well as methanol adsorption on the porous surfaces. These observations imply that the number of...
M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa
Iran with the second largest gas reserves in the world makes the importance of Kish Island more vital. Kish gas field, with a capacity of 67 trillion cubic meters gas, is one of the main hubs of Iran gas production. One of the uses of natural gas is to produce petrochemical goods such as Methanol. In this thesis the focus is on economical evaluation of producing Methanol for amount of 5,000 tons per day from Kish gas field. As a result, the required feed has been estimated about 150 million cubic feet per day and the net capital investment calculated to be 941 million US dollars. The initial estimate of Direct Permanent Investment (DPI) was calculated to be $590.8 million. Having considered...
Article International Journal of Hydrogen Energy ; Vol. 39, issue. 21 , July , 2014 , p. 11224-11240 ; ISSN: 03603199 ; Baghalha, M ; Sharif University of Technology
In this paper, a two-dimensional, two-phase, non-isothermal model is presented to predict the electrochemical, mass transfer and heat transfer behaviors in a direct methanol fuel cell (DMFC). Governing equations including the momentum, continuity, heat transfer, proton and electron transport, species transport for water, methanol, and all the gas species (carbon dioxide, methanol vapor, water vapor, oxygen, and nitrogen) and the auxiliary equations are coupled to studying the various phenomena in DMFC. The modeling results agree well with the four different experimental data in an extensive range of operation conditions. A parametric study is also performed to examine the effects of the cell...
Multi-objective optimization approach for green design of methanol plant based on CO2-efficeincy indicator, Article Journal of Cleaner Production ; 2014 ; ISSN: 09596526 ; Pishvaie, M. R ; Farhadi, F ; Sharif University of Technology
The aim of the present work is to propose an eco-design method for sustainable development of methanol production by implementing a multi-objective optimization model based on CO2-efficiency. Two different approaches for the methanol production, i.e. a conventional reference methanol case (RMC) and proposed green integrated methanol case (GIMC) were compared from the view point of eco-design. Using life cycle assessment and process simulation, the environmental features as well as operational decision variables of the RMC and GIMC were assessed. Based on the inventory analysis of LCA, it was found that carbon dioxide is the major emitted pollutant from methanol production. Thus the...
Article 20th International Congress of Chemical and Process Engineering, CHISA 2012, Prague, 25 August 2012 through 29 August 2012 ; 2012 , Pages 1179-1188 ; 18777058 (ISSN) ; Hosseinpour, V ; Sharif University of Technology
Acetic acid is one of the most important petrochemical products. Carbonylation of methanol in homogenous phase is one of the major routes for production of acetic acid. Amongst group VIII metal catalysts used in this process iridium has displayed the best capabilities. To investigate effect of operating parameters like: temperature, pressure, methyl iodide, methyl acetate, iridium, ruthenium, and water concentrations on the carbon dioxide formation, experimental design for this system based upon central composite design (CCD) was utilized. Statistical carbon dioxide formation equation developed by this method contained individual, interactions and curvature effects of parameters on the...
Article Journal of Chemical Technology and Biotechnology ; Volume 87, Issue 8 , 2012 , Pages 1111-1120 ; 02682575 (ISSN) ; Farhadi, F ; Pishvaie, M. R ; Sharif University of Technology
Background: A new design for a methanol plant is proposed in which CO 2 addition, as one of the important parameters, is used to optimize the synthesis gas composition. An attempt has been made to assess the environmental features as well as the process operability of the proposed plant, in which the required CO 2 is provided from reformer flue gas. As a starting point, simulation of a conventional reference methanol case (RMC) and also the proposed green integrated methanol case (GIMC) are performed to obtain operational and kinetic parameters. In order to compare properly GIMC and RMC, the objective function is defined so that SynGas production, and thereby methanol production, in the GIMC...
A comparative investigation of the electrocatalytic oxidation of methanol on poly-NiTCPP and poly-TCPP/Ni modified glassy carbon electrodes, Article Journal of Electroanalytical Chemistry ; Volume 663, Issue 1 , December , 2011 , Pages 14-23 ; 15726657 (ISSN) ; Haghighatbin, M. A ; Gobal, F ; Mahjani, M. G ; Rayati, S ; Sharif University of Technology
Electro-oxidation of methanol in alkaline solution at a glassy carbon electrode electrochemically modified by a conductive polymeric meso-tetra(4-carboxyphenyl)porphyrinato nickel(II), abbreviated as poly-NiTCPP and also meso-tetra(4-carboxyphenyl)porphyrin with incorporated nickel(II) cations, abbreviated as, poly-TCPP/Ni, were investigated and compared. Both films were prepared by oxidative electro-polymerization of complexes by repetitive cyclic voltammetry (RCV) in 0.1 M NaOH aqueous solution. The electrochemical properties and behaviors and also kinetic values of both films have been characterized and compared using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical...