Alkaline Saponification of Ethylene-Vinyl Acetate Copolymer

In the saponification process of an ethylene-vinyl acetate copolymer (EVAc) in methanol (MeOH) with an alkaline catalyst (NaOH), the ester exchange reaction occurs much faster than the direct saponification of EVAc or methyl acetate (MeOAc) produced by the ester exchange. Therefore, as the saponific...

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Bibliographic Details
Published inKOBUNSHI RONBUNSHU Vol. 35; no. 1; pp. 33 - 39
Main Authors IWASAKI, Hiroshi, YONEZU, Kiyoshi
Format Journal Article
LanguageJapanese
Published The Society of Polymer Science, Japan 25.01.1978
Subjects
Ethylene-Vinyl Acetate Copolymer
Ethylene-Vinyl Alcohol Copolymer
Multi-plate Distillation
Saponification
Saponification Apparatus
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Summary:In the saponification process of an ethylene-vinyl acetate copolymer (EVAc) in methanol (MeOH) with an alkaline catalyst (NaOH), the ester exchange reaction occurs much faster than the direct saponification of EVAc or methyl acetate (MeOAc) produced by the ester exchange. Therefore, as the saponification proceeds, the MeOAc accumulated during the reaction consumes a large amount of NaOH, making it difficult to produce a highly saponified EVAc, or ethylene-vinyl alcohol copolymer (EVA) without continuous removal of MeOAc from the system. Then, a multi-plates distillation tower was designed as a high pressure saponification apparatus for continuous removal of MeOAc. The solutions of EVAc in MeOH and of NaOH in MeOH were fed to the top plate of the tower and overheated MeOH vapor was fed into the tower from the bottom plate. By this procedure, azeotropic mixture of MeOH and MeOAc was removed from the top to yield a highly saponified EVAc. Thus, the continuous production of highly saponified EVAc was successfully achieved.
ISSN:0386-2186
1881-5685
DOI:10.1295/koron.35.33