Thermo-infrared-spectroscopy analysis of the interaction of naphthylammonium–montmorillonite with sodium nitrite |
| |
Authors: | Zohar Yermiyahu Isaak Lapides Shmuel Yariv |
| |
Institution: | (1) Department of Inorganic and Analytical Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel |
| |
Abstract: | The deep blue organoclay color pigment (OCCP), naphthylazonaphthylammonium–montmorillonite, was synthesized in an aqueous
suspension by treating montmorillonite with naphthylammonium chloride followed after 2 h by NaNO2. The reddish-brown azo dye naphthylazonaphthylamine (commercial name “Solvent Brown 3”) was synthesized in an aqueous solution
in the absence of clay from the same reagents. X-ray diffraction and thermo-infrared (IR) spectroscopy of organoclay prepared
by treating montmorillonite with naphthylammonium chloride showed that the organoclay contained two types of tactoids with
intercalated naphthylammonium cations and with naphthylammonium–naphthylamine associations. Naphthylammonium clay was obtained
after thoroughly washing the latter organoclay. IR spectra of naphthylamine, naphthylammonium chloride, naphthylammonium clay,
naphthylammonium–naphthylamine clay (with some naphthylammonium-clay), OCCP, and Solvent Brown 3 in KBr disks were recorded
before and after thermal treatments up to 120 °C. IR spectrum of the OCCP was similar to that of Solvent Brown 3. An NH3
+ group was identified in the spectrum of the OCCP but not in that of Solvent Brown 3. In the latter spectrum, an NH2 group was identified, suggesting that the amine group of the azo dye in the OCCP was protonated. It appears that the difference
in color between OCCP and Solvent Brown 3 resulted from the protonation of the azo molecule in the interlayer space of the
clay. |
| |
Keywords: | Azo pigments IR spectroscopy Montmorillonite Naphthylammonium– montmorillonite Naphthylammonium– naphthylamine– montmorillonite Naphthylazonaphthylamine Naphthylazonaphthylammonium– montmorillonite Organo clay color pigment (OCCP) Sodium nitrite Solvent brown 3 |
本文献已被 SpringerLink 等数据库收录! |
|