- Phosgene-free decomposition of dimethylhexane-1,6-dicarbamate over ZnO
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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
- Hyun, Min Jeong,Shin, Mi,Kim, Yong Jin,Suh, Young-Woong
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- Zn-Co bimetallic supported ZSM-5 catalyst for phosgene-free synthesis of hexamethylene–1,6–diisocyanate by thermal decomposition of hexamethylene–1,6–dicarbamate
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A set of mono- and bimetallic (Zn-Co) supported ZSM-5 catalysts was first prepared by PEG-additive method. The physicochemical properties of the catalysts were investigated by FTIR, XPS, XRD, N2 adsorption-desorption measurements, SEM, EDS and NH3-TPD techniques. The physicochemical properties showed that the ZnCo2O4 spinel oxide was formed on the ZSM-5 support and provided effectual synergetic effect between Zn and Co species for the bimetallic catalyst. Furthermore, bimetallic supported ZSM-5 catalyst exhibited weak, moderate and strong acidic sites, while the monometallic supported ZSM-5 catalyst showed only weak and moderate or strong acidic sites. Their catalytic performances for thermal decomposition of hexamethylene–1,6–dicarbamate (HDC) to hexamethylene–1,6–diisocyanate (HDI) were then studied. It was found that the bimetallic supported ZSM-5 catalysts, especially Zn-2Co/ZSM-5 catalyst showed excellent catalytic performance due to the good synergetic effect between Co and Zn species, which provided a suitable contribution of acidic sites. HDC conversion of 100% with HDI selectivity of 91.2% and by-products selectivity of 1.3% could be achieved within short reaction time of 2.5?h over Zn-2Co/ZSM-5 catalyst.
- Ammar, Muhammad,Cao, Yan,He, Peng,Wang, Li-Guo,Chen, Jia-Qiang,Li, Hui-Quan
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- METHOD FOR PREPARING ALIPHATIC DIISOCYANATE
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The present invention relates to a method for preparing an aliphatic diisocyanate by pyrolyzing an aliphatic dicarbamate in liquid phase, using a tin (II) or (IV) compound as a catalyst and a zwitterionic compound as a stabilizer, thereby remarkably inhibiting high-boiling by-products and providing the aliphatic diisocyanate with high yield.
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Paragraph 0032
(2014/10/16)
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