butadiene polymerization
Recently Published Documents


TOTAL DOCUMENTS

154
(FIVE YEARS 9)

H-INDEX

23
(FIVE YEARS 1)

Author(s):  
Mateus K. Vasconcelos ◽  
Márcio Nele ◽  
José Carlos Pinto

ABSTRACT Butadiene rubbers are frequently produced through solution polymerizations using Ziegler–Natta catalysts based on neodymium. Particularly, there is great interest in developing rubbers that present enhanced processability during the formulation step. For this reason, the present work investigated the production of butadiene rubbers in the presence of polar additives, such as methyl methacrylate, methacrylic acid, and water, through solution polymerizations, using neodymium versatate as catalyst. The obtained results confirmed the possibility of producing butadiene rubbers with polar character that presented improved processability properties during the vulcanization stage. In addition, a new use for water and the manufacture of copolymers of butadiene and oxygenated monomers in polymerization processes that make use of neodymium catalysts are reported for the first time.


2020 ◽  
Vol 344 ◽  
pp. 84-91 ◽  
Author(s):  
Carolina C. Gaioto ◽  
Martin Schmal ◽  
José Carlos da Silva Pinto

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3703 ◽  
Author(s):  
Christoph O. Hollfelder ◽  
Melanie Meermann-Zimmermann ◽  
Georgios Spiridopoulos ◽  
Daniel Werner ◽  
Karl W. Törnroos ◽  
...  

As previously shown for lutetium and yttrium, 1,2,3,4,5-pentamethylcyclopentadienyl (C5Me5 = Cp*)-bearing rare-earth metal dimethyl half-sandwich complexes [Cp*LnMe2]3 are now also accessible for holmium, dysprosium, and terbium via tetramethylaluminato cleavage of [Cp*Ln(AlMe4)2] with diethyl ether (Ho, Dy) and tert-butyl methyl ether (TBME) (Tb). C–H-bond activation and ligand redistribution reactions are observed in case of terbium and are dominant for the next larger-sized gadolinium, as evidenced by the formation of mixed methyl/methylidene clusters [(Cp*Ln)5(CH2)(Me)8] and metallocene dimers [Cp*2Ln(AlMe4)]2 (Ln = Tb, Gd). Applying TBME as a “cleaving” reagent can result in both TBME deprotonation and ether cleavage, as shown for the formation of the 24-membered macrocycle [(Cp*Gd)2(Me)(CH2OtBu)2(AlMe4)]4 or monolanthanum complex [Cp*La(AlMe4){Me3Al(CH2)OtBu}] and monoyttrium complex [Cp*Y(AlMe4)(Me3AlOtBu)], respectively. Complexes [Cp*Ln(AlMe4)2] (Ln = Ho, Dy, Tb, Gd) and [Cp*LnMe2]3 (Ln = Ho, Dy) are applied in isoprene and 1,3-butadiene polymerization, upon activation with borates [Ph3C][B(C6F5)4] and [PhNHMe2][B(C6F5)4], as well as borane B(C6F5)3. The trans-directing effect of AlMe3 in the binary systems [Cp*Ln(AlMe4)2]/borate is revealed and further corroborated by the fabrication of high-cis-1,4 polybutadiene (97%) with “aluminum-free” [Cp*DyMe2]3/[Ph3C][B(C6F5)4]. The formation of multimetallic active species is supported by the polymerization activity of pre-isolated cluster [(Cp*Ho)3Me4(CH2)(thf)2].


2019 ◽  
Vol 377 ◽  
pp. 367-377 ◽  
Author(s):  
Dirong Gong ◽  
Weilun Ying ◽  
Junyi Zhao ◽  
Wenxin Li ◽  
Yuechao Xu ◽  
...  

2019 ◽  
Vol 68 (8) ◽  
pp. 1484-1491 ◽  
Author(s):  
Feng Wang ◽  
Heng Liu ◽  
Yanming Hu ◽  
Xuequan Zhang

ACS Catalysis ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. 827-838 ◽  
Author(s):  
Bradley M. Schmidt ◽  
Aradhana Pindwal ◽  
Amrit Venkatesh ◽  
Arkady Ellern ◽  
Aaron J. Rossini ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document