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Phosgene-free decomposition of dimethylhexane-1,6-dicarbamate over ZnO

Title
Phosgene-free decomposition of dimethylhexane-1,6-dicarbamate over ZnO
Author
서영웅
Keywords
Catalytic decomposition; Hexamethylene-1,6-diisocyanate; Dimethylhexane-1,6-dicarbamate; ZnO
Issue Date
2016-01
Publisher
SPRINGER
Citation
RESEARCH ON CHEMICAL INTERMEDIATES, v. 42, Page. 57-70
Abstract
In catalytic decomposition of dimethylhexane-1,6-dicarbamate (HDC) into hexamethylene-1,6-diisocyanate (HDI), Zn-containing homogeneous (i.e., zinc acetate) and heterogeneous (i.e., ZnO) catalysts were active among a number of catalysts tested, due to the great electron withdrawing ability of Zn ions. Particularly, when polyethylene glycol dimethyl ether was used as a solvent, ZnO was found to be relatively robust, because the catalytic performance was maintained up to the third use (HDC conversion of 93 % and HDI yield of 67 % at 180 A degrees C for 1 h). Through investigation of a HDC/ZnO mixture at elevated temperatures by IR spectroscopy, a possible reaction scheme of ZnO-catalyzed decomposition of HDC was proposed. The H atom is removed from the N-H group of HDC by hydrogen bonding with an O site on the ZnO surface, followed by coordination of an O-C=O group in monodentate mode to a Zn site. The C-O group in the O-C=O linkage is then cleaved yielding the isocyanate and surface methoxide species. Finally, methanol is released from ZnO by a reaction between the surface methoxide and the hydroxyl species.
URI
https://link.springer.com/article/10.1007%2Fs11164-015-2224-xhttp://hdl.handle.net/20.500.11754/31704
ISSN
0922-6168; 1568-5675
DOI
10.1007/s11164-015-2224-x
Appears in Collections:
COLLEGE OF ENGINEERING[S](공과대학) > CHEMICAL ENGINEERING(화학공학과) > Articles
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