Synthesis of methacrylate-termindated polyethylene : compounds related to difluorofulvene and difluoroheptafulvene
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| Title: | Synthesis of methacrylate-termindated polyethylene : compounds related to difluorofulvene and difluoroheptafulvene |
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| Authors: | Yang, Keh chiang |
| Committee Members: | Elsheimer, Seth |
| Summary: | The title compound methacrylate-terminated polyethylene was successfully ynthesized from hydroxyl-terminated polyethylene. A very high yield (90%) was achieved from transesterification using dibutyltin oxide as catalyst. The IR spectrum of the final product shows a nearly complete disappearance of the broad hydroxy peak at 3328 cm-1 and the appearance of a stretching signal at 1721 cm·• (C=O) and a weaker signal at 1636 cm·• (C=C). Other methods for the preparation of the title ester such as Fischer esterifications or from acid derivatives are also discussed. IL Fluorine can act as an electron withdrawer (inductive effect) and it can also donate electrons (resonance effect). This research focused on the role fluorine plays regarding aromaticity in some conjugated cyclic systems. Unsuccessful attempts to synthesize 9-(difluoromethylene)fluorene suggested that fluorine is not an electron donor in this system. Likewise, successful preparation of 5-( difluoromethylene )dibenzosuberene supports the same conclusion. Comparision of the 13C NMR spectra of 5-( difluoromethylene )dibenzosuberene 95.1, C=CF2; 152.5, C=CFi) and l,l-diphenyl-2,2-difluoroethene (o 96.3, C=CF2; 153.9, C=CF2) did not give evidence of strong electronic effects. |
| URL: | https://stars.library.ucf.edu/rtd/3124 |
| Database: | OpenDissertations |
| Abstract: | The title compound methacrylate-terminated polyethylene was successfully ynthesized from hydroxyl-terminated polyethylene. A very high yield (90%) was achieved from transesterification using dibutyltin oxide as catalyst. The IR spectrum of the final product shows a nearly complete disappearance of the broad hydroxy peak at 3328 cm-1 and the appearance of a stretching signal at 1721 cm·• (C=O) and a weaker signal at 1636 cm·• (C=C). Other methods for the preparation of the title ester such as Fischer esterifications or from acid derivatives are also discussed. IL Fluorine can act as an electron withdrawer (inductive effect) and it can also donate electrons (resonance effect). This research focused on the role fluorine plays regarding aromaticity in some conjugated cyclic systems. Unsuccessful attempts to synthesize 9-(difluoromethylene)fluorene suggested that fluorine is not an electron donor in this system. Likewise, successful preparation of 5-( difluoromethylene )dibenzosuberene supports the same conclusion. Comparision of the 13C NMR spectra of 5-( difluoromethylene )dibenzosuberene 95.1, C=CF2; 152.5, C=CFi) and l,l-diphenyl-2,2-difluoroethene (o 96.3, C=CF2; 153.9, C=CF2) did not give evidence of strong electronic effects. |
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