Cationic ring-opening polymerizations of cyclic ketene acetals initiated by acids at high temperatures

Mapping the characteristics of the radical ring‐opening polymerization of a cyclic ketene acetal towards the creation of a functionalized polyester

“…The repeating unit B (Scheme ), after 1,7‐addition should be similar to the repeating unit found in unsaturated copolymers of ε‐caprolactone previously described by Detrembleur et al,34 and the repeating unit A should show resemblances to ring‐retained units of MDO and derivatives thereof 12, 35–37. The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ .…”

“…The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ . It has previously been shown that cationic polymerization products of other cyclic ketene acetals have a broad set of peaks in this region, corresponding to hydrogens in the OCH 2  position in ring‐retained units 12, 37. The 1 H‐ 13 C HMQC NMR spectrum, Figure 13, also confirms this assignment.…”

“…Detrembleur et al34 have demonstrated that protons g′ have a peak around 4.6–4.7 ppm and that the protons i′ and h′ display peaks around 5.6 and 5.8 ppm, respectively. Protons c′ are given a peak shift near to that of the monomer (5.7 ppm), as is the case for the comparable protons in the ring‐retained structure of polymerized MDO 12. Even though repeating units of 1,2‐ and 1,7‐addition seem to agree quite well with the NMR spectra, the incorporation of units by 1,5‐addition is also probable.…”

Mapping the characteristics of the radical ring‐opening polymerization of a cyclic ketene acetal towards the creation of a functionalized polyester

“…The repeating unit B (Scheme ), after 1,7‐addition should be similar to the repeating unit found in unsaturated copolymers of ε‐caprolactone previously described by Detrembleur et al,34 and the repeating unit A should show resemblances to ring‐retained units of MDO and derivatives thereof 12, 35–37. The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ .…”

“…The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ . It has previously been shown that cationic polymerization products of other cyclic ketene acetals have a broad set of peaks in this region, corresponding to hydrogens in the OCH 2  position in ring‐retained units 12, 37. The 1 H‐ 13 C HMQC NMR spectrum, Figure 13, also confirms this assignment.…”

“…Detrembleur et al34 have demonstrated that protons g′ have a peak around 4.6–4.7 ppm and that the protons i′ and h′ display peaks around 5.6 and 5.8 ppm, respectively. Protons c′ are given a peak shift near to that of the monomer (5.7 ppm), as is the case for the comparable protons in the ring‐retained structure of polymerized MDO 12. Even though repeating units of 1,2‐ and 1,7‐addition seem to agree quite well with the NMR spectra, the incorporation of units by 1,5‐addition is also probable.…”

Free-Radical Copolymerization Behavior of 5,6-Benzo-2-methylene-1,3-dioxepane and Methacrylic Acid via the in Situ Generation of 3-Methyl-1,5-dihydrobenzo[e][1,3]dioxepin-3-yl Methacrylate and 2-(Acetoxymethyl)benzyl Methacrylate

“…Some litertaure is available on cationic ring-opening polymerization of cyclic ketene acetals using initiators like H 2 SO4, TiCl 4 , BF 3 , etc. Depending on the temperature, either 1,2 vinyl addition at the double bond or a mixture of 1,2 vinyl addition and formation of ester linkages in the backbone by ring opening of BMDO is reported using cationic initiators. − In the present work, mixing BMDO with the acidic monomer MAA led to a new product, i.e., a new vinyl monomer characterized above with no ring-opening reaction. Figure shows the 1 H NMR spectra of the product formed after mixing BMDO and MAA for different intervals of time at 25 °C.…”

Diverse chemically recyclable polymers obtained by cationic vinyl and ring-opening polymerizations of the cyclic ketene acetal ester “dehydroaspirin”

“…This tendency contrasts with the cationic polymerization of CKAs, in which ROP becomes dominant upon increasing the temperature. 30…”

Mapping the characteristics of the radical ring‐opening polymerization of a cyclic ketene acetal towards the creation of a functionalized polyester

“…The repeating unit B (Scheme ), after 1,7‐addition should be similar to the repeating unit found in unsaturated copolymers of ε‐caprolactone previously described by Detrembleur et al,34 and the repeating unit A should show resemblances to ring‐retained units of MDO and derivatives thereof 12, 35–37. The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ .…”

“…The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ . It has previously been shown that cationic polymerization products of other cyclic ketene acetals have a broad set of peaks in this region, corresponding to hydrogens in the OCH 2  position in ring‐retained units 12, 37. The 1 H‐ 13 C HMQC NMR spectrum, Figure 13, also confirms this assignment.…”

“…Detrembleur et al34 have demonstrated that protons g′ have a peak around 4.6–4.7 ppm and that the protons i′ and h′ display peaks around 5.6 and 5.8 ppm, respectively. Protons c′ are given a peak shift near to that of the monomer (5.7 ppm), as is the case for the comparable protons in the ring‐retained structure of polymerized MDO 12. Even though repeating units of 1,2‐ and 1,7‐addition seem to agree quite well with the NMR spectra, the incorporation of units by 1,5‐addition is also probable.…”

Free-Radical Copolymerization Behavior of 5,6-Benzo-2-methylene-1,3-dioxepane and Methacrylic Acid via the in Situ Generation of 3-Methyl-1,5-dihydrobenzo[e][1,3]dioxepin-3-yl Methacrylate and 2-(Acetoxymethyl)benzyl Methacrylate

“…Some litertaure is available on cationic ring-opening polymerization of cyclic ketene acetals using initiators like H 2 SO4, TiCl 4 , BF 3 , etc. Depending on the temperature, either 1,2 vinyl addition at the double bond or a mixture of 1,2 vinyl addition and formation of ester linkages in the backbone by ring opening of BMDO is reported using cationic initiators. − In the present work, mixing BMDO with the acidic monomer MAA led to a new product, i.e., a new vinyl monomer characterized above with no ring-opening reaction. Figure shows the 1 H NMR spectra of the product formed after mixing BMDO and MAA for different intervals of time at 25 °C.…”

Diverse chemically recyclable polymers obtained by cationic vinyl and ring-opening polymerizations of the cyclic ketene acetal ester “dehydroaspirin”

“…This tendency contrasts with the cationic polymerization of CKAs, in which ROP becomes dominant upon increasing the temperature. 30…”

Mapping the characteristics of the radical ring‐opening polymerization of a cyclic ketene acetal towards the creation of a functionalized polyester

“…The repeating unit B (Scheme ), after 1,7‐addition should be similar to the repeating unit found in unsaturated copolymers of ε‐caprolactone previously described by Detrembleur et al,34 and the repeating unit A should show resemblances to ring‐retained units of MDO and derivatives thereof 12, 35–37. The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ .…”

“…The group of peaks between 3.6 and 4.6 ppm in the 1 H‐NMR spectra, Figure 12, are assigned to the protons b′ . It has previously been shown that cationic polymerization products of other cyclic ketene acetals have a broad set of peaks in this region, corresponding to hydrogens in the OCH 2  position in ring‐retained units 12, 37. The 1 H‐ 13 C HMQC NMR spectrum, Figure 13, also confirms this assignment.…”

“…Detrembleur et al34 have demonstrated that protons g′ have a peak around 4.6–4.7 ppm and that the protons i′ and h′ display peaks around 5.6 and 5.8 ppm, respectively. Protons c′ are given a peak shift near to that of the monomer (5.7 ppm), as is the case for the comparable protons in the ring‐retained structure of polymerized MDO 12. Even though repeating units of 1,2‐ and 1,7‐addition seem to agree quite well with the NMR spectra, the incorporation of units by 1,5‐addition is also probable.…”

Free-Radical Copolymerization Behavior of 5,6-Benzo-2-methylene-1,3-dioxepane and Methacrylic Acid via the in Situ Generation of 3-Methyl-1,5-dihydrobenzo[e][1,3]dioxepin-3-yl Methacrylate and 2-(Acetoxymethyl)benzyl Methacrylate

“…Some litertaure is available on cationic ring-opening polymerization of cyclic ketene acetals using initiators like H 2 SO4, TiCl 4 , BF 3 , etc. Depending on the temperature, either 1,2 vinyl addition at the double bond or a mixture of 1,2 vinyl addition and formation of ester linkages in the backbone by ring opening of BMDO is reported using cationic initiators. − In the present work, mixing BMDO with the acidic monomer MAA led to a new product, i.e., a new vinyl monomer characterized above with no ring-opening reaction. Figure shows the 1 H NMR spectra of the product formed after mixing BMDO and MAA for different intervals of time at 25 °C.…”

Diverse chemically recyclable polymers obtained by cationic vinyl and ring-opening polymerizations of the cyclic ketene acetal ester “dehydroaspirin”

“…This tendency contrasts with the cationic polymerization of CKAs, in which ROP becomes dominant upon increasing the temperature. 30…”