Abstract:
Provided are methods forming polymers. The methods include, for example, tandem carbonylation and polymerization reactions, where epoxides are catalytically carbonylated to form lactones and the lactones catalytically polymerized to form polymers without the need to isolate or purify the lactone intermediate. Also provided are methods for catalytically polymerizing beta-propiolactone. Homopolymers and copolymers can be formed using the methods disclosed herein.
Abstract:
Cs-Symmetric pyridylamidohafhium catalyst precursors and active species based thereon are described. The active species are used for living polymerization of C 2 -C 20 alkenes and provide highly isotactic polypropylene and are useful to provide multi-block copolymer with end blocks of isotactic polypropylene or isotactic poly(4-methyl-1-pentene).
Abstract:
Isotactic polyethers, methods of making polyethers, and uses of polyethers. The polyethers have a chain transfer group formed from a chain transfer agent. The methods of making the polyethers use monoalcohol chain transfer agents or multifunctional chain transfer agents. The polyethers can be used in materials, such as polyurethanes, elastomers, thermoset plastics, and thermoplastics, and as non-ionic surfactants.
Abstract:
The present invention relates to olefin polymerization catalysts including a novel phenoxyaminetitanium(II) alkene complex, rac-Lig2 TiBn, which is inactive for olefin polymerization upon benzyl abstraction, treatment with ethylene leads to the formation of a stable titanacyclopentane complex (rac-Lig2(CH2)2TiBn). Six-membered metallacycle complexes (rac-Lig1ZrBn2-a,b and rac-Lig1HfBn2-a,b) were obtained from reaction of the vinylappended ligand with tetrabenzylzirconium (ZrBn4) or tetrabenzylhafnium (HfBn4). Living and isoselective polymerization of 1-hexene was promoted by rac-Lig1HfBn2- a,b/B(C6F5)3 at 0°C, while rac-Lig1ZrBn2-a,b/B(C6F5)3 catalyzed the living and isoselective polymerization of propylene at 0°C. This catalyst system was employed for the synthesis of a diblock copolymer featuring an isotactic polypropylene semicrystalline block and poly(ethylene-co-propylene) amorphous block. Complexes derived from rac-Lig1HfBn2-a,b and rac-Lig1ZrBn2-a,b also served as highly active cyclopolymerization catalysts for 1,5- hexadiene which furnished poly(methylene-l,3-cyclopentane) with a predominance of cis- cyclopentane rings. Lastly, cyclopolymerization of 1,6-heptadiene with rac-Lig1HfBn2- a,b/B(C6F5)3 produced poly(methylene-1,3-cyclohexane) with a nearly perfect cis-isotactic microstructure.
Abstract:
The invention provides: imidazole and imidazolium compounds of formulas (I) and (II): (Formulas (I), (II)); polymers containing a plurality of imidazolium-containing repeating units of formula (III'): (Formula (III')); and membranes and devices comprising the polymers. Also provided are methods of making the inventive compounds and polymers.
Abstract:
Phosphazenium-based ionomers and methods of making them are disclosed. The ionomers are useful in making membranes for fuel cells and other devices that benefit from extremely base-stable membranes. The polymers (ionomers) contain repeating units of formula: in which all of R1, R2, W, Y and Z are hydrocarbon.
Abstract:
One step ortho-alkylation of anilines with styrenes to give chiral anilines is obtained using a strong acid catalyst, e.g. CF 3 SO 3 H. Condensation of the product to give ligand and metallation gives complex which catalyzes polymerization of propylene to give isotactic propylene or regiorandom propylene of low PDI or blocks thereof, depending on polymerization temperature.
Abstract translation:使用强酸催化剂,例如使用苯乙烯,苯乙烯,苯乙烯进行一步邻位烷基化得到手性苯胺。 CF 3 SUB> SO 3 SUB>小时。 产物给予配体和金属化的缩合得到复合物,其根据聚合温度,催化丙烯的聚合,得到低PDI或其嵌段的全同立构丙烯或异氰酸酯丙烯。