Highly Active Copolymerization of Ethylene and N-Acetyl-O-(ω-Alkenyl)-l-Tyrosine Ethyl Esters Catalyzed by Titanium Complex

Abstract

A series of N-acetyl-O-(ω-alkenyl)-L-tyrosine ethyl esters were synthesized by the reaction of vinyl bromides (4-bromo-1-butene, 6-bromo-1-hexene, 8-bromo-1-octene and 10-bromo-1-decene) with N-acetyl-L-tyrosine ethyl ester. 1 H NMR, elemental analysis, FT-IR, and mass spectra were performed for these N-acetyl-O-(ω-alkenyl)-L-tyrosine ethyl esters. The novel titanium complex can catalyze the copolymerization of ethylene and N-acetyl-O-(ω-alkenyl)-L-tyrosine ethyl esters efficiently and the highest catalytic activity was up to 6.86ˆ10 4 gP¨(molTi)´1¨h´1. The structures and properties of the obtained copolymers were characterized by FT-IR, ( 1 H) 13 C NMR, GPC, DSC, and water contact angle. The results indicated that the obtained copolymers had a uniformly high average molecular weight of 2.85ˆ10 5 g¨mol´1 and a high incorporation ratio of N-acetyl-O-(but-3-enyl)-L-tyrosine ethyl ester of 2.65 mol % within the copolymer chain. The units of the comonomer were isolated within the copolymer chains. The insertion of the polar comonomer into a copolymer chain can effectively improve the hydrophilicity of a copolymer.

GRAPHENE OXIDE AND A GO/ZnO NANOCOMPOSITE AS CATALYSTS FOR EPOXY RING-OPENING OF EPOXIDIZED SOYBEAN FATTY ACIDS METHYL ESTERS

“…823 and 842 cm -1 in the FTIR spectrum (Figure 7) evidences the oxirane ring-opening, as well as the absorption band at ca. 1234 cm -1 related to the acetyl groups present in the structure (Azeh et al, 2013;Wang et al, 2016). Another important indication of the addition of acetic anhydride in the modified FAME is the presence of the vibrational mode at ca.…”