Bis(alkylphenylaminopyridinato) titanium dichlorides as ethylene polymerization catalysts

Four titanium complexes derived from 2-(2-ethylanilino)-, 2-(3,5-dimethylanilino)pyridine, 2-(4-n-butylanilino)- and 2-(2-t-butylanilino)pyridine were synthesized and characterized by spectroscopic methods. These complexes were used to catalyze the polymerization of ethylene in the presence of MAO as cocatalyst. The effect of the complex structures on the polymerization behavior was studied. All the alkylphenylaminopyridinato titanium complexes used in this study yielded higher molar masses than the unsubstituted bis(phenylaminopyridinato) titanium dichloride complex. Correspondingly, activities were lower and molar mass distributions were broader than those in the case of the unsubstituted bis(phenylaminopyridinato) titanium catalyst. The fluxional behavior of alkylphenylaminopyridinato titanium catalysts is probably the reason for the broad molar mass distributions. This might be due to the electron-donating effect from the alkyl substituent because the alkyl substituent enhances the active site isomerization rate.     

Catalytic polymerization of ethylene by non-metallocene Zirconium(IV) calix[4] pyrrole complexes

Some zirconium compounds containing chelating diamido dipyrrole or tetra-amido tetra-pyrrole ligands were synthesized and used as polymerization catalyst with high polymerization activity of ethylene at 40 °C and 1 bar, in presence of MAO or B(C₆F₅)₃ as co-catalyst. The maximum catalytic activity reached 1100 Kg/mol bar h for ethylene polymerization by Zr₂(octa-phenyl calix[4]pyrrolidine)Cl₄. These results reveal that half-zirconocene like complexes including four terminal chlorine and one calix[4]pyrrolidine in middle with both π and σ-interaction have the highest ethylene polymerization turnover (compounds 13, 14).     

Manganese and Iron Complexes with Malonic Acid Bis[2-(3,5-di-tert-butyl-2-hydroxybenzyl)hydrazide]

Russian Journal of General Chemistry - New manganese(II) and iron(III) complexes with hydrazones derived from malonic acid dihydrazide and 3,5-di-tert-butylsalicylaldehyde have been synthesized....     

Effect of association processes on polymerization of N-[3-(dimethylamino)propyl]methacrylamide salts in aqueous solutions

The effect of associative interactions of monomers and propagating macroradicals in homopolymerization of N-[3-(dimethylamino)propyl]methacrylamide salts and their copolymerization with acrylonitrile and acrylamide in aqueous solution was studied.     

Highly fluorous zirconocene(IV) complexes and their catalytic applications in the polymerization of ethylene

The catalytic activities of the highly fluorous systems formed by the zirconocene(IV) complexes [Zr{η⁵-C₅H₄SiMe₂C₂H₄R_F}₂Cl₂] (R_F = C₆F₁₃ (4a), C₁₀F₂₁ (4b)) or [Zr-{η⁵-C₅H₃(SiMe₂C₂H₄C₆F₁₃)₂}₂Cl₂] (5a) and MMAO in toluene have been studied and compared with analogous nonfluorous systems generated from [Zr{η⁵-C₅H₄SiMe₃}₂Cl₂] and [Zr{η⁵-C₅H₅}₂Cl₂]. Although less active than the reference systems, the fluorous catalysts are stable over prolonged polymerization times, giving rise to polymers with similar molecular weights to those obtained with [Zr{η⁵-C₅H₄SiMe₃}₂Cl₂].     

新树型配体 TBOAA 与钴配合物的研究

研究了新配体N，N’，N”－（三苯甲酰）－三乙氨基胺（TOBAA）与二价钴离子生成配合物的光度特征和电化学特征。在较宽的pH范围内，新试剂和钴离子形成2：1的配合物，并且在一定范围内其吸光度与浓度具有良好的线性关系。     

Bis[3-(3,5-dialkyl-4-hydroxyphenyl)propyl]mono- and disulfides as the Sevilen stabilizers

The effect of the shielding degree of the phenol hydroxy group on the hydrolytic and thermal stability of ethylene-vinyl acetate copolymer (Sevilen) was studied on a series of phenols containing one or two sulfur atoms in the aliphatic chain of the para-substituent. Among the synthesized compounds a group of disulfides was found with a high antioxidant efficiency, which increase the Sevilen hydrolytic stability. The most effective are the 6-tert-butyl-2-methylphenol derivatives.     

Reaction of N-(2-pyridylmethyl)-3,5-dimethylbenzamide and N-(3-pyridylmethyl)-3,5-dimethylbenzamide N-oxides with acetic anhydride

As a continuation of our work on the reaction of N-pyridylmethyl-3,5-dimethylbenzamide N-oxides with acetic anhydride, we now report a study of the reaction of N-(2-pyridylmethyl)-3,5-dimethylbenzam.de N-oxide ( 5 ) and N-(3-pyridylmethyl)-3,5-dimethylbenzamide N-oxide ( 6 ) with acetic anhydride. Compound 5 gave N,N′-di(3,5.dimethylbenzoyl)-1,2-di(2.pyridyl)ethenediamine ( 7 ) and 3,5-dimethylbenzamtde ( 8 ). Compound 6 afforded three products formulated as 2-acetoxy-3-(3,5-dimethylbenzoylaminomethyl)pyridine ( 12 ), 3-(3,5-dimethylbenzoylaminomethyl)-2-pyridone ( 13 ) and 5-(3,5-dimethylbenzoylaminomethyl)-2-pyridone ( 14 ). Analytical and spectral data are presented which support the structures proposed.     

Specific features of ethylene polymerization on self-immobilizing catalytic systems based on titanium bis(phenoxy imine) complexes

The kinetics of ethylene polymerization on six methylalumoxane-activated self-immobilizing bis(phenoxy imine) complexes of titanium chloride with allyloxy groups in the m- and p-positions of the N-phenyl ring and with various substituents in the salicylaldehyde fragment was studied. The activity of the complexes in the temperature range 20–60°C and ethylene pressure of 0.4 MPa was evaluated.