Waste‐free synthesis and production all across chemistry with the benefit of self‐assembled crystal packings

Abstract

A systematic mechanistic discussion of solid-state reactions (intracrystalline, intercrystalline, gas-solid thermal, or photochemical) at local molecular resolution is the basis for industrial sustainable production with waste-free solid-gas and stoichiometric solid-solid reactions at low energy requirement. These profit from the bargain of the self-assembled crystal packing. They rapidly complete to give 100% yield and require no solvent for workup. The basic requirements are thermodynamic feasibility and anisotropic molecular migrations at local pressure or suction in opposition to claims of 'minimal atomic and molecular movements' that do not know gas-solid and solid-solid reactions. Topochemical failures are settled on that experimental basis by atomic force microscopy (AFM), correlation with the crystal packing, scanning near field optical microscopy (SNOM), and nanoscratching. A general three-step phase rebuilding mechanism is derived that provides directions for all experimental situations including stereoregular polymerizations. Heat control in gas-solid equipment and solid-solid small-scale vibration or large-scale rotation ball-mills is essential. If AFM identifies (nano)liquids cooling is required. Also rare cases of surface passivation are detected by AFM. Molecular solid-state chemistry and mechanochemistry are differentiated. Solid-state techniques easily exclude moisture and are able to synthesize hitherto inaccessible compounds. Some of the latter are selected for discussion out of more than 1000 waste-free solid-state reactions in addition to already executed kg-scale productions using reasonably inexpensive starting materials with promise for industrial applications and extensions.

Organic Solid-State Reactions

“…The head-to-tail specificity is preparatively secured. The shrinking is verified by crater formation with sharp rims from AFM scans on single crystals [6,48,90]. The linear gas-solid-catalyzed dimerization of 2-vinylnaphthalene at −10 ∘ C provides only the (Z)-product with quantitative yield [90].…”

“…The thorough "predictive" failure of the "topochemical" hypothesis of 1964 is also evident by the [4 + 4] photodimerization of anthracenes (Scheme 1) [6]. First, the "distance limit" of 4.2 Å in anthracene crystals is considerably superseded with now d = 6.038 Å, but the packing sketch along [0 0 1] shows that molecules can easily slip together for reaction.…”

“…) by careful AFM measurements on several crystallographic faces [18]. Upon shrinking in a direction that is accommodated by the crystal packing, holes will ensue at the surface [6].…”

“…The only possibility for relief of enormous local pressure is molecular migration. This has been amply published since 1992 and reviewed [6,7]. Further images can be found in the cited original publications.…”

Solvent-Free Biginelli Reactions Catalyzed by Hierarchical Zeolite Utilizing a Ball Mill Technique: A Green Sustainable Process

“…There is lack of knowledge about organic chemists in ball mills chemistry. The interest in this technique has intensified in the last 10 years, resulting in frequent, acceptable synthetic methods that covering the whole scope of organic synthesis [40,41]. More recently, a solvent-free ball milling Biginelli reaction utilizing subcomponent synthesis was reported [42].…”