Mechanochemically assisted hydrolysis in the ADOR process

Abstract

Efficient hydrolysis of zeolites in the ADOR process using mechanochemistry, including economical enrichment with 17O for solid-state NMR.

17O NMR spectroscopy of crystalline microporous materials

“…Their high molecular weight, bulk and low framework polarity also means that they are poorly soluble and are most appropriately used in heterogenous reactions, either A particularly intriguing approach is to exploit the 17 of the local structure (resulting from the presence of residual water in the interlayer space) continued even after the "final" IPC-2P product was formed, despite no obvious changes in the powder XRD pattern (or indeed the 29 Si NMR spectrum) over this period. A similar reaction was studied by Rainer et al, 61 using mechanochemistry. 17 Recent work has also investigated the lability of conventional (i.e., non ADOR-able) zeolite frameworks in ambient aqueous conditions using 17 O NMR spectroscopy, with MAS and MQMAS spectra used to follow the (in situ) enrichment of MOR, FER and CHA frameworks by reaction with H 2 17 O(l) at room temperature.…”

“…6d ) after the initial reaction indicated that rearrangement of the local structure (resulting from the presence of residual water in the interlayer space) continued even after the “final” IPC-2P product was formed, despite no obvious changes in the powder XRD pattern (or indeed the 29 Si NMR spectrum) over this period. A similar reaction was studied by Rainer et al , 61 using mechanochemistry. 17 O NMR spectra showed enrichment of the Si– 17 O–Si linkages in UTL after only ∼30 min (at 150 rpm), with the presence of a signal thought to be attributable to Si– 17 O–Ge at short reaction times (which has not yet been observed in hydrothermal reactions).…”

“…In recent work by Rainer et al , 61 mechanochemistry was applied in zeolite hydrolysis, with 100 μL of 40% H 2 17 O(l) added during ball milling (at 150 rpm) of 500 mg of (unenriched) Ge-UTL in an ADOR reaction, 39,43 leading to an overall enrichment level in the daughter zeolite of 10%. In this context, mechanochemistry offers a simple and cost-efficient route to enrichment of novel zeolitic products that are difficult to synthesise and enrich using more traditional routes.…”

In situ flow pair distribution function analysis to probe the assembly–disassembly–organisation–reassembly (ADOR) mechanism of zeolite IPC-2 synthesis

“…This peak corresponds to the d 200 Please do not adjust margins Please do not adjust margins interlayer distance and is commonly followed in ADOR reactions to observe the distance between the silica-rich layers and therefore identify the ADOR product present. 23 The 2θ position (Figure S3) around 7.35° indicates that the product at the end of the data collection is IPC-2P, the partially connected intermediate of IPC-2, with a typical peak position around 7.5°. 12 The proposed final product of IPC-2P is further supported by in-house PXRD data of the recovered hydrolysis sample (from the APS) and the following calcination to produce IPC-2 (Figure S4).…”

New avenues for mechanochemistry in zeolite science

“…In the mechanochemically assisted approach, known products of the ADOR process were afforded without the need for a heating source, in only 30 min and with a significantly decreased amount of liquid. 126 Interestingly, in this new method the highest acid concentrations (12 M HCl) led to the denser PCR framework (Fig. 8), in contrast to the usually obtained OKO structure.…”