DBU-Intercalated α-Zirconium Phosphates as Latent Thermal Catalysts in the Reaction of Hexamethylene Diisocyanate and Phenol

Osamu Shimomura,Hideki Kusu,Atsushi Ohtaka,Ryôki Nomura

doi:10.3390/catal11050614

Osamu Shimomura, Hideki Kusu + Show 2 more

Open Access

https://doi.org/10.3390/catal11050614

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Journal: Catalysts	Publication Date: May 11, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Osaka Institute of Technology

Abstract

The catalytic activity of 1,8-diazabicyclo [5,4,0]undec-7-ene-intercalated α-zirconium phosphates (α-ZrP·DBU) as thermal latent catalysts in the reaction of hexamethylene diisocyanate (HDI) and phenol was investigated. α-ZrP intercalation compounds with varying amounts of DBU (α-ZrP·xDBU, where x = 0.58, 0.44, 0.22, and 0.10) were prepared. The reaction of HDI and phenol with α-ZrP·DBU was carried out at varying temperatures for 30 min periods. The α-ZrP·DBU showed high catalytic activity in the reaction of HDI-phenol under heating conditions. The α-ZrP·DBU extended the pot lifetimes at 25 °C.

Highlights

DBU (1,8-diazabicyclo [5,4,0]undec-7-ene) has been widely used as a catalyst for preparation of polyurethanes [1,2]
We examined the catalytic activity of α-Zr(HPO4 )2 ·H2 O (α-ZrP)·DBU in the reaction of hexamethylene diisocyanate (HDI) and phenol as a model reaction in polyurethane synthesis
We studied how to extend the time for uniform mixing and molding by using DBU-intercalated αzirconium phosphate as a thermal latent catalyst for polyurethane synthesis

Summary

Introduction

DBU (1,8-diazabicyclo [5,4,0]undec-7-ene) has been widely used as a catalyst for preparation of polyurethanes [1,2]. In the preparation of polyurethane using DBU, an organic strong base catalyst, it is difficult to control the molding time due to the rapid reaction. It is very important to perform uniform mixing and molding of polyurethane to extend the pot lifetime. To resolve this problem, blocked isocyanates have been used to avoid unexpected reactions [3,4,5,6]. By adjusting the mixing ratio of DBU-acetylacetone for the suppression of DBU activity, the pot lifetime was extended and the components reacted at low temperature. We reported that DBU-intercalated α-zirconium phosphate (α-ZrP·DBU) served as a latent thermal catalyst in the reaction of epoxy resins.

Results and Discussion

Materials

Measurements

Typical Model Reaction Procedure of HDI and Phenol

Conclusions