In order to extend application of the gel-degradation mechanism of delignification, model compounds of the general structure (3,4-dimethoxyphenyl)-CH(OR)R$ sp prime$ were treated at room temperature with increasing charges of molecular Cl$ sb2$ in glacial HOAc. / Catalytic amounts of Cl$ sb2$ cleaved benzyl aryl ether bonds (OR=2-methoxy-4-methylphenoxy) before any ring chlorination occurred. Yields of cleavage decreased in the order: R$ sp prime$=H; R$ sp prime$=$-$CH$ sb2$-2-methoxyphenoxy; R$ sp prime$=$-$CH(CH$ sb2$OH)-2-methoxyphenoxy. These results support the concept that the delignification of wood pulp by chlorine results from benzyl aryl ether cleavage. The conditions of the reaction, as well as control reactions with hydrochloric acid, suggest that the cleavage is due to conventional acid hydrolysis induced by chlorine. The experimental evidence does not rule out another possible mechanism in which the cleavage is initiated by molecular chlorine. / Benzyl ether links were generally stable in models of the benzyl alkyl type, whose primary reactions were ring chlorination. A large excess of chlorine caused side-chain displacement, hitherto considered the primary reaction in the solubilization of lignin.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.70291 |
| Date | January 1991 |
| Creators | Fruteau de Laclos, Anne-Marie F. (Anne-Marie François) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001274157, proquestno: AAINN74632, Theses scanned by UMI/ProQuest. |
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