fig3

Figure 3. NMR spectra of methanol, SMSs and acetal species on SAPO-34. (A) Magnifications of two-dimensional ¹³C-¹³C (blue) and ¹³C-¹H (red) solid-state NMR spectra acquired with a mixing time of 150 ms and a cross-polarization contact time of 500 µs. (B) Structures associated with peaks related to different surface species including methanol, DME and SMSs. (C) Identification of a surface adduct between an SMS and methanol (solid arrows: electron flows, dotted arrows: ¹³C-¹³C NMR correlation). (D) Chemical exchange of anomeric conformations of DMM as evident from the ¹³C-¹³C NMR data. (E) Identification of methanediol from the ¹³C-¹H NMR data with a cross-polarization contact time of 50 µs. Reproduced with permission from ref. 36^[36]. Copyright 2016, Wiley-VCH. NMR: Nuclear magnetic resonance; DME: dimethyl ether; SMSs: surface methoxy species.