Sulfite esters as products of the interaction in sulfur dioxide – alkanol – tris(hydroxymethyl)aminomethane systems

Abstract

The reaction products formed in the SO₂ – ROH – (HOCH₂)₃CNH₂ (where R – CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉ and n-C₅H₁₁) systems were isolated and identified as: binary salt – ammonium O-methylsulfite [(HOCH₂)₃CNH₃]⁺ [CH₃OSO₂]⁻ (1); 1/1 charge transfer complex between diethyl sulfite (2) and tris(hydroxymethyl)aminomethane by S-N binding; polymorhps of zwitterionic internal salt – O-sulfite tris(hydroxymethyl)methylammonium (at R – n-C₄H₉ and n-C₅H₁₁); and its solvates with n-propanol 1/1 (3) and isopropanol 2/1. The structures of all synthesized products were confirmed by FT-IR, Raman, ¹H NMR and ¹³C NMR spectrometry, and the structure of 1 and 3 was characterized by crystal X-ray diffraction studies as well.

GRAPHICAL ABSTRACT

KEYWORDS:

• Sulfur dioxide
• alkanol
• tris(hydroxymethyl)aminomethane
• sulfite esters
• zwitterionic internal salt

Disclosure statement

No potential conflict of interest was reported by the author(s).