| Summary: | 碩士 === 國立中興大學 === 化學工程學系 === 89 === Because of increasing quantity of PU wastes internationally coupling with growing environmental concern for the TDI production tars, current burning and burial methods of dealing with these problems are clearly not acceptable. Since these materials are mostly isocyanate derivatives containing urethane, urea and carbodiimde functionality, this research attempts to find a common chemical solution of dealing with these materials. Our research has been using alcoholysis of PU materials with n-butanol and ethylene glycol to digest the wastes and converted them into low molecular weight alcohols and amines for further uses.
In order to demonstrate the feasibility of this approach, our experiment started with alcholysis of model derivatives of phenyl isocyanate that include urethane, urea, dimer, trimer, and others with n-butanol, and established that most of isocyanate derivatives could be converted at 240℃ into n-butyl carbamate and aniline in good yield. In addition, by treating the same model derivatives of phenyl isocyanate with ethylene glycol, we uncovered that the alcoholysis all goes through ethylene carbonate as intermediate which reacts further with aniline to form 2-anilinoethanol as the EG alcholysis product.
Finally, we are able to demonstrate that both alcoholysis methods could digest polyurethanes, such as flexible and rigid foams, or polycarbonate into low molecular weight alcohols and amines of definite structures. It is hoping that further works will carry on to find the use of these low molecular weight alcohols and amines as PU raw materials.
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