Quantum Chemical Simulation of the Interaction of Functional Groups in Polyurethanes with 3d-Metal Ions During Their Extraction from Aqueous Solutions

M A Ksenofontov,V S Vasil’Eva,M B Shundalau,E Yu Bobkova,L E Ostrovskaya

doi:10.1007/s10812-017-0550-z

M A Ksenofontov, V S Vasil’Eva + Show 3 more

Open Access

https://doi.org/10.1007/s10812-017-0550-z

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Abstract

The interaction of the functional groups in the polyurethane foam adsorbent Penopurm® with the cations of some 3d-metals upon their extraction from aqueous solutions has been studied by atomic emission spectroscopy, UV/Vis and vibrational IR spectroscopy, and quantum chemical simulation using density functional theory. Penopurm® absorbs 3d-metal cations from aqueous solutions in the pH range 5–7. Some spectral criteria have been found indicating a predominant interaction of Ni2+ ions with various fragments of the polyurethane foam structure.

Highlights

Gasfilled crosslinked polymers, including polyurethane foams (PUF), contain two types of cells: macrocells with diameter from several tens to hundreds of microns and microcells with diameter from 0.01 to 1.0 mm
In contrast to fragments I and III, in which the urethane group is isolated by the phenyl and methylene groups, an interaction exists in fragment II between the urethane group and the attached urea group
This interaction results in a redistribution of the electron density localized on the –Ο–C(O)–N– fragment of the urethane group leading to significant change in the frequencies of the vibrations of this fragment

Summary

Introduction

Gasfilled crosslinked polymers, including polyurethane foams (PUF), contain two types of cells: macrocells with diameter from several tens to hundreds of microns and microcells with diameter from 0.01 to 1.0 mm. Each of the fragments contains a polar functional group such as the hydroxyl (OH) or carbonyl group (C=O) or a heteroatom In contrast to fragments I and III, in which the urethane group is isolated by the phenyl and methylene groups, an interaction exists in fragment II between the urethane group and the attached urea group This interaction results in a redistribution of the electron density localized on the –Ο–C(O)–N– fragment of the urethane group leading to significant change in the frequencies of the vibrations of this fragment (see Table 2). The models of complexes A, B, and C are constructed considering the coordination of the oxygen atoms of the ester, carbonyl, and hydroxyl groups (fragment I) to the Ni2+ ion, respectively. In complex A (Fig. 5a), the ester group oxygen atoms and the urethane nitrogen atoms are coordinated

Fragment II

Complex B

Complex E