The effect of treatment with sodium carbonate and hydrogen on the activity and selectivity of polymeric Pd-containing catalysts for hydrogenation of acetylene compounds

2021 ◽  
Vol 1 (1-2) ◽  
pp. 86-96
Author(s):  
A. A. Bertova ◽  
A. A. Korshakova ◽  
A. V. Bykov ◽  
M. G. Sulman ◽  
L. Zh. Nikoshvili ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Atmospheric Pressure ◽  
Palladium Catalysts ◽  
High Selectivity ◽  
Industrial Process ◽  
Polymeric Support ◽  
Amino Groups ◽  
Carbon Carbon Bond ◽  
Effect Of Treatment ◽  
Acetylene Compounds

Catalytic hydrogenation of the triple carbon-carbon bond of acetylene compounds is an important industrial process. High selectivity to the olefin compound should be provided in the process. This study considers the effect exerted by sodium carbonate treatment of the palladium catalysts containing super-cross-linked polystyrene (SPS) on their activity and selectivity in the hydrogenation of 2-methyl- 3-butin-2-ol and phenylacetylene. The effect of such treatment was shown to depend on the chosen palladium precursor and the type of polymeric support (non-functionalized SPS or that containing ternary amino groups). At atmospheric pressure of hydrogen and a temperature of 90 °C in a toluene medium, the 1%-Pd/SPS catalysts treated with Na2CO3 provided a 98 % selectivity in the hydrogenation of 2-methyl-3-butin-2-ol (at a 95 % conversion of the substrate), while selectivity in the hydrogenation of phenylacetylene reached 99.5 %.

Effect of Treatment with Sodium Carbonate and Hydrogen on the Activity and Selectivity of Pd-Containing Polymer Catalysts for the Hydrogenation of Acetylene Compounds

2021 ◽  
Vol 13 (3) ◽  
pp. 280-288
Author(s):  
A. V. Bertova ◽  
A. A. Korshakova ◽  
A. V. Bykov ◽  
M. G. Sulman ◽  
L. Zh. Nikoshvili ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Effect Of Treatment ◽  
Acetylene Compounds

Vanadium-Chromium Oxide: Effective Catalysts for Ammoxidation of 3-Picoline

2013 ◽  
Vol 634-638 ◽  
pp. 624-627 ◽  
Author(s):  
Feng Jiang ◽  
Wei Xu ◽  
Lei Niu ◽  
Guo Min Xiao
Keyword(s):  
Raman Spectroscopy ◽  
Catalytic Activity ◽  
Chromium Oxide ◽  
Atmospheric Pressure ◽  
High Selectivity ◽  
Surface Acidity ◽  
N2 Adsorption ◽  
Composite Oxide ◽  
Highly Active

Bulk vanadium-chromium oxide (VCrO) catalyst was prepared and characterized by N2 adsorption, XRD, NH3-TPD, H2-TPR, and Raman spectroscopy. XRD and Raman results showed that the VCrO catalyst was a kind of VV-CrIII composite oxide mainly consisted of crystalline V2O5 and CrVO4-Ⅲ (orthorhombic). NH3-TPD and H2-TPR results revealed that this catalyst had negligible surface acidity, and was easily reduced due to the formation of CrVO4-Ⅲ. Their catalytic activity was evaluated in the ammoxidation of 3-picoline to nicotinonitrile. Catalytic results showed that the bulk VCrO catalyst was highly active and selective; the nicotinonitrile selectivity and yield was up to 96.1%, 88.2% respectively at atmospheric pressure and 360 °C. The high selectivity was related closely to the low surface acidity of the catalyst.

scholarly journals Development Of Atmospheric Pressure Plasma Jet In Air

2012 ◽  
Vol 8 (1) ◽  
pp. 15-22 ◽  
Author(s):  
RB Tyata ◽  
DP Subedi ◽  
A Shrestha ◽  
D Baral
Keyword(s):  
Atmospheric Pressure ◽  
Polymer Surface ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Optical Measurements ◽  
Atmospheric Pressure Plasma Jet ◽  
Pressure Plasma ◽  
Large Structures ◽  
Small Flow ◽  
Effect Of Treatment

In this paper, an atmospheric pressure plasma jet (APPJ) in air that is expected to be useful for polymer surface modification has been reported. The plasma jet was produced by applying (10 - 30) kHz, (0 - 20) kV AC source. The electrical and optical measurements have also been reported. The use of solenoid as an external electrode has been found to be more effective in boosting the jet to a distance up to 30 mm even with a small flow rate of air. The characteristic of the proposed APPJ was investigated by measuring the effect of treatment on a PE film on the jet for different exposition time and distance from the nozzle. It has been confirmed that the jet can modify polymer film with a work distance of over 25mm. This plasma jet can be useful for the treatment and cleaning of objects having large structures and could be used in wider areas of application. DOI: http://dx.doi.org/10.3126/kuset.v8i1.6035 KUSET 2012; 8(1): 15-22

Use of Pd/sepiolite systems as hydrogenation catalysts. II. Hydrogenolysis of N-blocked amino acids and dipeptides by hydrogen transfer

1987 ◽  
Vol 65 (12) ◽  
pp. 2791-2797 ◽  
Author(s):  
A. Aramendia ◽  
V. Borau ◽  
C. Jimenez ◽  
J. M. Marinas ◽  
M. E. Sempere
Keyword(s):  
Amino Acids ◽  
Palladium Catalysts ◽  
Hydrogen Transfer ◽  
Hydrogen Donor ◽  
Amino Groups ◽  
Promoting Effect ◽  
Hydrogenation Catalysts ◽  
Ultrasonic Agitation

We have carried out the deprotecting of various N-protected amino acids and dipeptides by subjecting them to hydrogen transfer with several palladium catalysts supported on different solids. The hydrogen donor itself has been used "insitu" to reduce the corresponding Pd salt on the support. We have also analyzed the effect of various factors on the deprotecting rate for Z-glycine. Such factors include the procedure used in synthesizing the catalysts ("insitu" or by conventional reduction), the type of support, hydrogen donor, promoting effect of alkaline hydroxides, type of reactor (closed or open), and magnetic or ultrasonic agitation. We have found that the ease of adsorption of the protected amino groups (Z—NH—) is fundamental in accounting for the order of deprotecting rates found. We have compared the activity of new catalysts in the deprotecting process with that of a commercial one containing 10% Pd over carbon, supplied by Fluka (ref. 75990).

Hydrogenation of cinnamyl methyl ether and allylbenzene on palladium catalysts

1987 ◽  
Vol 52 (4) ◽  
pp. 1015-1020 ◽  
Author(s):  
Libor Červený ◽  
Ivo Paseka ◽  
Eva Fialová ◽  
Vlastimil Růžička
Keyword(s):  
Double Bond ◽  
Solvent Effect ◽  
Benzene Ring ◽  
Methyl Ether ◽  
Atmospheric Pressure ◽  
Palladium Catalysts ◽  
Polar Medium ◽  
Adsorbed Molecules ◽  
Ionic Nature ◽  
Bond Splitting

The hydrogenation of cinnamyl methyl ether and allylbenzene in hexane and acetone at 20 °C and atmospheric pressure of hydrogen has been studied on eight palladium catalysts. The hydrogenation of cinnamyl methyl ether is accompanied by C-O bond splitting giving rise to propylbenzene and methanol, the hydrogenation of allylbenzene is associated with the isomerization of the double bond resulting in its conjugation with the benzene ring. A marked solvent effect on the selectivity of hydrogenation of cinnamyl methyl ether has been observed and ascribed to the effect of solvated protons on the adsorbed molecules of the ether which is promoted by polar medium. The solvent effect on the isomerization of allylbenzene during the hydrogenation is little pronounced, which suggests that this reaction is not of ionic nature.

Effect of Heat Treated Sisal Fiber on Physical Properties of Polypropylene Composites

2010 ◽  
Vol 123-125 ◽  
pp. 1123-1126 ◽  
Author(s):  
Sulawan Kaewkuk ◽  
Wimonlak Sutapun ◽  
Kasama Jarukumjorn
Keyword(s):  
Atmospheric Pressure ◽  
Mechanical Tests ◽  
Sisal Fiber ◽  
Molding Machine ◽  
Polypropylene Composite ◽  
Polypropylene Composites ◽  
Heat Treated ◽  
Effect Of Treatment ◽  
Sisal Fibers ◽  
Internal Mixer

Sisal fiber reinforced polypropylene composites were prepared using an internal mixer. Heat treatred sisal fibers were performed by heating the fibers in an oven at 150, 170, and 200°C under an atmospheric pressure and a presence of air. The composites prepared at a fiber content of 20 wt% were molded by an injection molding machine for mechanical tests including tensile and impact properties. Morphologies of the composites were examined using a scanning electron microscope (SEM). Viscosity at various shear rate of the composites were also investigated. Tensile strength and impact strength of heat treated sisal fiber/polypropylene composites were slightly higher than that of the untreated sisal fiber/polypropylene composite. However, no remakable effect of treatment temperatures on the mechanical and rheological properties of the composites was observed. SEM micrographs revealed that the heat treatment improved adhsion between the fiber and PP matrix.

Polymer-modified supported palladium catalysts for the hydrogenation of acetylene compounds

2016 ◽  
Vol 57 (3) ◽  
pp. 360-367 ◽  
Author(s):  
A. K. Zharmagambetova ◽  
K. S. Seitkalieva ◽  
E. T. Talgatov ◽  
A. S. Auezkhanova ◽  
G. I. Dzhardimalieva ◽  
...  
Keyword(s):  
Palladium Catalysts ◽  
Supported Palladium Catalysts ◽  
Supported Palladium ◽  
Acetylene Compounds

scholarly journals Synthesis of O-tyrosine Phosphorylated Adducts of Methylphosphonic and Phosphoric Acid Derivatives as Reference Compounds for the Analysis of Biomedical Samples

2019 ◽  
Vol 3 (2) ◽  
pp. 103-110
Author(s):  
Krylov V.I. Rybalchenko I.V.
Keyword(s):  
Atmospheric Pressure ◽  
The Body ◽  
Chemical Weapons ◽  
Amino Groups ◽  
Chemical Agents ◽  
Chemical Weapons Convention ◽  
Toxic Agents ◽  
Protective Groups ◽  
Derivatives Of ◽  
Reference Samples

Organophosphorus chemical agents are included in the 1st List of the Annex on Chemicals of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction (Chemical Weapons Convention, CWC). For the purposes of verification of compliance with the provisions of the CWC, special methods, which are considered the most informative at determining the retrospective effects of organophosphorus toxicants on the body, are necessary. Typical long-lived biomarkers of organophosphate toxic agents are tyrosine phosphorylation products, the presence of which in biomedical samples clearly indicates the exposure to sarin, soman, tabun and V-series agents. We have elaborated methods for the synthesis and isolation of tyrosine adducts derivatives of methylphosphonic and phosphoric acids, used as reference samples. The synthesis scheme included the consecutive protection of carboxyl and amino groups of tyrosine, its O-phosphorylation by the corresponding alkylphosphonates and phosphates, the removal of protective groups with the release of corresponding O-phosphorylated tyrosine adducts. Their purification from im purities was carried out, using column chromatography (SiO2, eluent: dichloromethane/ethyl acetate 1:1). The purity of the obtained products was more than 90 %, so it was possible to involve them in further transformations with the use of catalyst without the threat of its «poisoning». Benzyl and carboxybenzyl protection of phosphorylated L-tyrosines (12–17) was removed by means of catalytic hydrogenation by molecular hydrogen under atmospheric pressure. Target adducts of phosphorylated reagents and L-tyrosin were obtained (63–82 %) in form of crystal white substances, readily soluble in water and ethanol, and poorly – in dichloromethane and acetonitrile

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