scholarly journals Effects of Various Mixed Metal Chlorides- AlCl3 in TiCl4/MgCl2/THF Catalytic System on Ethylene Polymerization

2015 ◽  
Vol 14 (2) ◽  
pp. 12
Author(s):  
Nittaya Sudsong ◽  
Wanna Phiwkliang ◽  
Bunjerd Jongsomjit ◽  
Piyasan Praserthdam
Keyword(s):  
Catalytic System ◽  
Ethylene Polymerization ◽  
Catalyst System ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Metal Chlorides ◽  
Mixed Metal ◽  
Icp Analysis ◽  
Co Addition

In this research, the modification of TiCl4/MgCl2/THF catalyst system with various metal chlorides was investigated on ethylene polymerization. Experimentally, metal chlorides (CaCl2, FeCl2 and ZnCl2) were simultaneously introduced different with TiCl4/MgCl2/THF catalyst. ICP analysis was used to determine the total amount of each metal in the catalyst. For polymerization reaction, TEA was used as cocatalyst and hexane was used as a medium solvent. The Al/Ti molar ratio was 140. The activity result of Ca-Al, Zn-Al and Fe-Al was 979, 1009 and 1476 kgPE/molTi.h, respectively. The coaddition of AlCl3 and FeCl2 in TiCl4/MgCl2/THF catalyst system exhibited the highest activity. It suggested that the co-addition of AlCl3 and FeCl2 has higher electronegativity (EN) and the radius of Fe2+ is closer to Mg2+ resulting in an increased efficiency of the THF removal. This result led to improve the catalyst performance.

Preparation of Polyethylene with Vanadium/Titanium Bi-Metal Ziegler-Natta Catalysts

2014 ◽  
Vol 665 ◽  
pp. 335-338
Author(s):  
Tao Jiang ◽  
Xiang Lu Gao
Keyword(s):  
Ethylene Polymerization ◽  
Bimetallic Catalyst ◽  
Gel Permeation Chromatography ◽  
Catalyst System ◽  
Molar Ratio ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Vanadium Titanium ◽  
Ziegler Natta Catalysts ◽  
C Nmr

The catalyst with magnesium chloride supported vanadium/titanium bimetallic Ziegler-Natta catalysts has been prepared. The effects of V/Ti molar ratio and dosage of α-olefin on catalytic activity of ethylene polymerization were investigated. Gel permeation chromatography (GPC),13C-NMR spectra and differential scanning calorimetry (DSC) analysis were performed to characterize the polymers. The results indicated that the bimetallic catalyst system produced PE with broad and bimodal MWD.

scholarly journals Selective Catalytic Oxidation of Toluene to Benzaldehyde: Effect of Aging Time and Calcination Temperature Using CuxZnyO Mixed Metal Oxide Nanoparticles

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 354
Author(s):  
Khadijah H. Alharbi ◽  
Ali Alsalme ◽  
Ahmed Bader A. Aloumi ◽  
Mohammed Rafiq H. Siddiqui
Keyword(s):  
Metal Oxide ◽  
Calcination Temperature ◽  
Aging Time ◽  
Metal Oxide Nanoparticles ◽  
Catalytic Performance ◽  
Molar Ratio ◽  
Mixed Metal Oxide ◽  
Toluene Oxidation ◽  
Mixed Metal ◽  
Selective Catalytic Oxidation

Oxidation is an important organic transformation, and several catalysts have been reported for this conversion. In this study, we report the synthesis of mixed metal oxide CuxZnyO, which is prepared by a coprecipitation method by varying the molar ratio of Cu and Zn in the catalytic system. The prepared mixed metal oxide CuxZnyO was evaluated for catalytic performance for toluene oxidation. Various parameters of the catalytic evaluation were studied in order to ascertain the optimum condition for the best catalytic performance. The results indicate that aging time, calcination temperature, reaction temperature, and feed rate influence catalytic performance. It was found that the catalyst interfaces apparently enhanced catalytic activity for toluene oxidation. The XRD diffractograms reveal the crystalline nature of the mixed metal oxide formed and also confirm the coexistence of hexagonal and monoclinic crystalline phases. The catalyst prepared by aging for 4 h and calcined at 450 °C was found to be the best for the conversion of toluene to benzaldehyde while the reactor temperature was maintained at 250 °C with toluene fed into the reactor at 0.01 mL/min. The catalyst was active for about 13 h.

scholarly journals Enzymatic synthesis and characterization of novel terpolymers from renewable sources

2019 ◽  
Vol 91 (3) ◽  
pp. 397-408
Author(s):  
Diana Aparaschivei ◽  
Anamaria Todea ◽  
August E. Frissen ◽  
Valentin Badea ◽  
Gerlinde Rusu ◽  
...  
Keyword(s):  
Polymerization Reaction ◽  
Molar Ratio ◽  
Condensation Polymerization ◽  
Average Molecular Mass ◽  
New Class ◽  
Platform Chemicals ◽  
Starting Point ◽  
Reaction Cycles ◽  
Methylene Group

Abstract 2,5-Furandicarboxylic acid and itaconic acid are both important biobased platform chemicals and their terpolymer with 1,6-hexanediol (HDO) can be the starting point for a new class of reactive polyesters, with important applications. The green synthetic route developed in this study involves a biocatalytic condensation polymerization reaction of dimethyl furan-2,5-dicarboxylate (DMFDC) and dimethyl itaconate (DMI) with HDO in toluene at 80°C, using commercial immobilized lipases from Candida antarctica B. In the best conditions, the formed polymer product was isolated with more than 80% yield, containing about 85% terpolymer with average molecular mass of about 1200 (Mn, calculated from MALDI-TOF MS data) and 15% DMFDC_HDO copolymer. Considering the higher reactivity of DMFDC, the composition of the synthesized polymer can be directed by adjusting the molar ratio of DMFDC and DMI, as well as by extending the reaction time. Structural analysis by NMR demonstrated the regioselective preference for the carbonyl group from DMI adjacent to the methylene group. The biocatalyst was successfully reused in multiple reaction cycles.

EPR spectroscopic study of Ni(I) species in the catalyst system for ethylene polymerization based on α-diimine Ni(II) complex activated by MMAO

2019 ◽  
Vol 880 ◽  
pp. 267-271 ◽  
Author(s):  
Igor E. Soshnikov ◽  
Nina V. Semikolenova ◽  
Konstantin P. Bryliakov ◽  
Artem A. Antonov ◽  
Wen-Hua Sun ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Ethylene Polymerization ◽  
Catalyst System

Metathetical Degradation and Depolymerization of Unsaturated Polymers

1997 ◽  
Vol 70 (3) ◽  
pp. 519-529 ◽  
Author(s):  
J. C. Marmo ◽  
K. B. Wagener
Keyword(s):  
Molecular Weight ◽  
Transition Metal ◽  
Catalytic System ◽  
Lewis Acid ◽  
Catalyst System ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Side Reactions

Abstract The employment of transition metal catalysts has been a viable route in the degradation and depolymerization of unsaturated polymers. Initially, unsaturated polymers were degraded with a catalytic system containing a transition metal and a Lewis acid cocatalyst (WCl6/SnBu4). Degradation chemistry was effective in reducing the molecular weight of the polymer, however, the classical catalyst system induces side reactions which generates ill-defined products. These side reactions were obviated by using a preformed alkylidene without a Lewis acid cocatalyst, and perfectly difunctional telechelics were synthesized.

(Pyrazol-1-yl)carbonyl palladium complexes as catalysts for ethylene polymerization reaction

2013 ◽  
Vol 724 ◽  
pp. 95-101 ◽  
Author(s):  
Hosana D. Mkoyi ◽  
Stephen O. Ojwach ◽  
Ilia A. Guzei ◽  
James Darkwa
Keyword(s):  
Ethylene Polymerization ◽  
Palladium Complexes ◽  
Polymerization Reaction

Characteristics and Applications of Nanostructured Nitrides Synthesized by Vapor Phase Reactions

2005 ◽  
Vol 876 ◽  
Author(s):  
Gerald Ziegenbalg ◽  
Carsten Pätzold ◽  
Ute Ŝingliar ◽  
Rico Berthold
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Vapor Phase ◽  
Elevated Temperatures ◽  
Catalyst Support ◽  
Chemical Properties ◽  
Molar Ratio ◽  
Basic Catalyst ◽  
Metal Chlorides ◽  
Amorphous Silicon Nitride

AbstractGas phase ammonolysis of volatile metal chlorides at elevated temperatures is a favorable way to produce nitride or oxynitride nanopowders. Their composition as well as the physico-chemical properties is determined by reaction temperature, molar ratio of the reactants and the residence time of the gases in the reaction zone. Both single and multi component powders can be obtained. Typical particle sizes are in the range of 50 to 350 nm. The specific surface can reach values up to 300 m2/g. Microporous analysis revealed the presence of pores with a diameter between 0.6 and 0.7 nm in amorphous silicon nitride. The powders can be used, depending on the characteristics, as catalyst or basic catalyst support. The paper gives an overview about vapor phase synthesis of single and multi component nitrides as well as the use of amorphous silicon nitride as a basic catalyst support for dehydrogenation of propane.

Preparation and Research of Skeletal Pt-C Compounds

2018 ◽  
Vol 937 ◽  
pp. 83-87 ◽  
Author(s):  
Xin Ling Hu ◽  
Ying Jiang Qian ◽  
Dong Xu Li ◽  
Xiao Min Chen
Keyword(s):  
Optical Properties ◽  
Synthesis Method ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Excellent Performance ◽  
Electrical And Optical Properties ◽  
Cermet Material ◽  
New Synthesis ◽  
New Ideas ◽  
New Type

Platinum matrix composite is a new type of functional pottery material, which has excellent mechanical, electrical and optical properties. Due to the complexity of the synthesis method and the expensive equipment, the development of cermet material is extremely slow, so that the method to solve the problem is urgently needed. In view of the excellent performance of the Pt-C compounds, by hydrothermal method and high temperature roasting method, a new synthesis method for the composite is proposed using melamine and four platinum chloride at 60 °C by the polymerization reaction with a molar ratio of 20:1. The synthetic of Pt-C compounds provides a new synthesis method and new ideas and at the same time the Pt-C compounds has excellent performance, showing the excellent applications in machining.

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