DFT molecular modeling studies were undertaken to shed light on possible activation and deactivation mechanisms of Ziegler−Natta catalytic systems, as well the for their reactivation by organohalides. We focused our efforts Ti species attached (110) lateral cut MgCl2. First, adsorbed TiCl4 leading an TiIII bearing a Ti−alkyl bond coordination vacancy, which is able undergo chain-growth, was considered. According calculations formation first active can be easily rationalized cleavage Ti−Cl...

Fe(HSO4)3 efficiently catalyzes the synthesis of 2-amino-4H-chromenes. The reactions proceed through a one-pot, three-component condensation α- or β-naphthol, aromatic aldehyde derivatives, and malonitrile in presence catalytic amount ferric hydrogen sulfate. Also, resorcinol, malononitrile, various aldehydes using catalyst gave corresponding 2-amino-4H-chromenes good yields. displayed high activity recyclability without loss its activity. Additionally, three Zr-based FI catalysts were...

A cadmium (II) ion selective electrode (ISE) based on an ion-imprinted polymer (IIP) as a novel ionophore has been prepared and studied. The ion-selective was by dispersing IIP particles in 2-nitrophenyloctyl ether plasticizer then embedding them polyvinylchloride polymeric matrix. Cd(II) ISE showed nernstian response for over the dynamic concentration range of 2.0 × 10−7–1.0 10−2 mol L−1, with slope 29.9 mV per decade. limit detection 1.0 10−7 M. proposed revealed good selectivity wide...

Extensive use of rubber in industrial articles and their eventual disposal at the end useful service life has created a major concern for environment. In automotive applications, ethylene–propylene–diene (EPDM) is used to manufacture various parts which will be difficult dispose or scrap. A microwave oven was as heating source, with aid some chemical agents aromatic aliphatic oils, cured EPDM waste powder devulcanized temperatures ranging from 200°C 260°C. The then revulcanized sulfur cure...

ABSTRACT A novel series of homo‐, bi‐, and mononuclear Ni(II)‐based catalysts (BNC n = 1–4, MNC 4 ) were used for ethylene polymerization. The optimum conditions the catalyst BNC (the highest catalytic activity) was obtained at [Al]/[Ni]=2000/1, T p 42 °C, t 20 min that 1073 g PE/mmol Ni h. In theoretical study, steric electronic effects substituents diimine backbone led to prominent influence on behavior. M V resulted from polymerization using ; however, unsaturation content 1 . GPC...

A series of dinuclear pyridyl‐imine Co‐ and Ni‐based complexes (Co: C 1 2 Ni: 3 4 ) were prepared in reasonable yields through one‐pot synthesis method. Toward ethylene oligomerization/polymerization, , activated by MMAO, capable to produce oligomers with moderate activity (up 5.1 × 10 5 g mol −1 Co h for which α‐C 8 was the major product. In contrast, polymerized that twofold greater than . The high impact o ‐substituent along dinuclearity effect leading productivity selectivity...

Abstract In arid and semi‐arid regions of the world, agricultural production is greatly limited by water scarcity inefficient use. Water‐absorbent hydrogels are a technological solution that can retain soil for plants. A lignin‐based hydrogel as natural plant‐based absorbent prepared from lignin alkali polymers poly(ethylene glycol) diglycidyl ether (PEGDGE) in adjusted (NaOH) solution. The maximum swelling capacity achieved 1.5 m NaOH with 0.5 mmol PEGDGE g. Water 34 g dry weight distilled...

Abstract Catalysts have a major role in the polymerization of olefins and exert their influence three ways: (1) behaviour, including activity kinetics; (2) polymer particle morphology, bulk density, size, size distribution shape; (3) microstructure, molecular weight regulation, chemical composition short‐ long‐chain branching. By tailoring catalyst structure, such as creation bridge or introducing substituent on ligand, metallocene catalysts can play achievement desirable properties. Kinetic...

Abstract A facile method for the synthesis of benzo[ f ]chromene derivatives is reported. The procedure involves a novel three-component reaction 1-naphthol or 2-naphthol, acetophenone and triethyl orthobenzoate in presence silica supported ionic liquid [pmim]HSO 4 SiO2 [silica 1-methyl-3-(triethoxysilylpropyl)imidazolium hydrogensulfate] as an efficient catalyst.

Abstract Several organohalide (HC) compounds were tested as promoters for a Ti‐based Ziegler‐Natta (Z‐N) catalyst at different polymerization conditions. Results show that the intensity of promoting effect depends on nature and amount promoters. A proper amount, especially optimum aliphatic type organohalides leads to strong productivity, aromatic ones weak productivity improvement; however, 3‐chloro‐1‐propene poison even lower HC/Ti molar ratios. Among studied compounds, chlorocyclohexane...

Abstract Spherical MgCl 2 ·nEtOH was prepared by adducting ethanol to using melt quenching method. Effect of molar ratio [EtOH]/[MgCl ] = 2.8–3.05 on the morphology and particle size were studied. The best adduct spherical obtained when 2.9 mol 1 used. An emulsion dissolved in a reactor containing silicon oil. Stirrer speed its transfer rate section that work at −10 −40°C are affected particle. adducted partially removed with controlled heat primary catalyst preparation (support). Treatment...

Abstract A Ziegler‐Natta/metallocene hybrid catalyst was produced and utilized in the polymerization of ethylene with aim producing bimodal polyethylene. The MgCl 2 adduct prepared by a melt quenching method Cp ZrCl TiCl 4 catalysts were loaded, respectively, after treating surface TiBAl. kinetics involved an induction period, followed fragmentation expansion particles. SEM micrographs revealed that spherical morphology retained through initial mild reaction conditions period. polymers...

Abstract Summery: A Ziegler‐Natta catalyst of MgCl 2 (ethoxide type)/TiCl 4 has been synthesized. In order to obtain ultra high molecular weight polyethylene (UHMWPE) tri‐isobutylaluminum which is less active chain transfer was used as cocatalyst. Slurry polymerization carried out for the ethylene while, dilute solution viscometry performed viscosity average (Mv) measurement. The effect [Al]/[Ti] molar ratio, temperature, monomer pressure and time on Mv productivity have investigated....