The stereoselective polymerization of β-myrcene and β-ocimene and their binary copolymerization with styrene promoted by titanium complexes dichloro1,4-dithiabutanediyl-2,2â²-bis(4,6-di-tert-butyl-phenyl)titanium (1), dichloro1,4-dithiabutanediyl-2,2â²-bis[4,6-bis(2-phenyl-2-propyl)phenoxy]titanium (2) and Ti(η5-C5H5)-(η2-MBMP)Cl (3) (MBMP = 2,2âmethylenebis(6-tert-butyl-4-methylphenoxo)) activated by methylaluminoxane (MAO) is reported. Complex 1 produces a prevalently trans-1,4-polymyrcene (92%), the more sterically encumbered pre-catalyst 2 gives a major amount of 3,4-units (40%). Conversely the pre-catalyst 3 produces cis-1,4-polymyrcene with good selectivity (92%). The catalyst 1 promotes the copolymerization of β-myrcene with styrene giving the corresponding copolymers in a wide range of composition (Ïs = 0.14â0.90). In the case of β-ocimene the catalysts 1 and 2 produce a polymer with 1,4-trans structure (70%) at 70 °C while at lower temperature (0 °C) an isotactic poly-1,2-ocimene (>99%) is obtained. The catalyst 3 produces a less stereoregular polymer with prevalently cis-1,4-microstructure (55%). The catalyst 2 also promotes the copolymerization of β-ocimene with styrene in a wide range of composition (Ïs = 0.23â0.87).
Stereoselective polymerization of biosourced terpenes β-myrcene and β-ocimene and their copolymerization with styrene promoted by titanium catalysts
Buonerba, Antonio;Luciano, Ermanno;Grassi, Alfonso;Proto, Antonio;Capacchione, Carmine
2017
Abstract
The stereoselective polymerization of β-myrcene and β-ocimene and their binary copolymerization with styrene promoted by titanium complexes dichloro1,4-dithiabutanediyl-2,2â²-bis(4,6-di-tert-butyl-phenyl)titanium (1), dichloro1,4-dithiabutanediyl-2,2â²-bis[4,6-bis(2-phenyl-2-propyl)phenoxy]titanium (2) and Ti(η5-C5H5)-(η2-MBMP)Cl (3) (MBMP = 2,2âmethylenebis(6-tert-butyl-4-methylphenoxo)) activated by methylaluminoxane (MAO) is reported. Complex 1 produces a prevalently trans-1,4-polymyrcene (92%), the more sterically encumbered pre-catalyst 2 gives a major amount of 3,4-units (40%). Conversely the pre-catalyst 3 produces cis-1,4-polymyrcene with good selectivity (92%). The catalyst 1 promotes the copolymerization of β-myrcene with styrene giving the corresponding copolymers in a wide range of composition (Ïs = 0.14â0.90). In the case of β-ocimene the catalysts 1 and 2 produce a polymer with 1,4-trans structure (70%) at 70 °C while at lower temperature (0 °C) an isotactic poly-1,2-ocimene (>99%) is obtained. The catalyst 3 produces a less stereoregular polymer with prevalently cis-1,4-microstructure (55%). The catalyst 2 also promotes the copolymerization of β-ocimene with styrene in a wide range of composition (Ïs = 0.23â0.87).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.