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    Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes

    , Article Journal of Industrial and Engineering Chemistry ; 2015 ; ISSN: 1226086X Tourani, S ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
    Abstract
    Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.% of palladium on activated carbon)... 

    Activation of CX (=Cl, Br) bond in aryl halides toward the palladium-catalyzed Heck reaction using 2,6-bis(diphenylphosphino)pyridine

    , Article Journal of Molecular Catalysis A: Chemical ; Volume 366 , January , 2013 , Pages 30-35 ; 13811169 (ISSN) Ataei, A ; Nadri, S ; Rafiee, E ; Jamali, S ; Joshaghani, M ; Sharif University of Technology
    2013
    Abstract
    The 2,6-bis(diphenylphosphino)pyridine/palladium catalytic system successfully catalyzes the Heck coupling reaction of less reactive aryl chlorides as well as aryl bromides with styrene to give the corresponding olefins in reasonable yields. TBAB (tetrabutylammoniumbromide) as an additive was found to be essential for these reactions. The results of Heck reaction exhibited a high selectivity (>99/1) favoring the trans product  

    Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes

    , Article Journal of Industrial and Engineering Chemistry ; Volume 28 , August , 2015 , Pages 202-210 ; 1226086X (ISSN) Tourani, S ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2015
    Abstract
    Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.%... 

    A high performance multi-walled carbon nanotube-supported palladium catalyst in selective hydrogenation of acetylene-ethylene mixtures

    , Article Applied Catalysis A: General ; Volume 399, Issue 1-2 , May , 2011 , Pages 184-190 ; 0926860X (ISSN) Bazzazzadegan, H ; Kazemeini, M ; Rashidi, A. M ; Sharif University of Technology
    2011
    Abstract
    In this research, a palladium nanocatalyst was synthesised over a multi-walled carbon nanotube (MWCNT) support and then applied for selective hydrogenation of acetylene in an ethylene-richflow stream. This material displayed a very promising selectivity toward ethylene production with increasing temperature, and also suppressed oligomer formation during acetylene hydrogenation. New operating conditions for selective hydrogenation of acetylene in an ethylene-richflow were introduced. This nanocatalyst gave a considerably higher yield, as high as 93%, than that previously obtained for ethylene production. It was postulated that the governing mechanism for acetylene hydrogenation over 0.5 wt.%... 

    Effects of functionalization and catalyst treatments on selective behavior of multi-walled carbon nanotube-supported palladium catalysts in hydrogenation of acetylene

    , Article Research on Chemical Intermediates ; Volume 41, Issue 2 , 2015 , Pages 1023-1034 ; 09226168 (ISSN) Bazzazzadegan, H ; Kazemeini, M ; Rashidi, A. M ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    Abstract
    Two nanocatalysts of palladium over multi-walled carbon nanotubes (MWCNT) were synthesized and their catalytic properties evaluated in selective hydrogenation of acetylene. Different procedures were applied to synthesize catalysts which resulted in two distinct average particle sizes of palladium (Pd) over the MWCNT. The resulting catalysts displayed dissimilar NH3-TPD behaviors as well as different selectivity performances at lower temperatures. While enhancement of the hydrogen transfer mechanism occurred upon the temperature increase, similar behaviors for the aforementioned materials were obtained. Furthermore, it was revealed that the catalytic performance at higher temperatures did not... 

    Hydrogenation of crude terephthalic acid by supported Pd and Pd-Sn catalysts on functionalized multiwall carbon nanotubes

    , Article Chemical Engineering Research and Design ; Volume 109 , 2016 , Pages 41-52 ; 02638762 (ISSN) Tourani, S ; Safekordi, A. A ; Rashidzadeh, M ; Rashidi, A. M ; Khorasheh, F ; Sharif University of Technology
    Institution of Chemical Engineers  2016
    Abstract
    Liquid phase hydro-purification of crude terephthalic acid (CTA) was performed using supported Pd and Pd-Sn catalysts on functionalized multi-wall carbon nanotubes (FMWCNT). Pd/FMWCNT catalysts were prepared by wet impregnation with Pd loadings of 0.05 to 0.6 wt.%. Pd-Sn/FMWCNT catalysts were prepared by co-impregnation (CI) and successive impregnation (SI) using 0.3 wt.% Pd loading and Sn/Pd molar ratios of 0.1 and 0.35 for the CI method and 0.05 to 0.35 for the SI method. Pd loading of 0.3 wt.% for Pd/FMWCNT was sufficient to decrease the 4-carboxybenzaldehyde (4-CBA) content of CTA from 2100 ppm to 5.5 ppm without excessive hydrogenation of terephthalic acid (TA). The commercial catalyst... 

    Suzuki–Miyaura coupling reaction in water in the presence of robust palladium immobilized on modified magnetic Fe3O4 nanoparticles as a recoverable catalyst

    , Article Applied Organometallic Chemistry ; Volume 32, Issue 2 , 2018 ; 02682605 (ISSN) Dadras, A ; Naimi Jamal, M. R ; Moghaddam, F. M ; Ayati, S. E ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Abstract
    Aryl halides and especially inactive aryl chlorides were coupled to benzenoid aromatic rings in a Suzuki–Miyaura coupling reaction in the absence of organic solvents and toxic phosphine ligands. The reaction was catalysed by a recoverable magnetic nanocatalyst, Pd@Fe3O4, in aqueous media. This method is green, and the catalyst is easily removed from the reaction media using an external magnetic field and can be re-used at least 10 times without any considerable loss in its activity. The catalyst was characterized using scanning and transmission electron microscopies, thermogravimetric analysis, inductively coupled plasma spectroscopy, Fourier transform infrared spectroscopy, CHN analysis,...