Organic Solid-State Reactions

Kaupp, Gerd

doi:10.1002/9781118468586.epoc2005

Cited by 17 publications

(15 citation statements)

References 238 publications

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“…Consequently, solvation and desolvation phenomena can be neglected [4–6]. Mechanochemical syntheses of organic systems provide for example an efficient method for cocrystal screening [7–9], an increased product selectivity [2,10–12], and a pathway to new products, which are inaccessible via traditional methods [3,13–14]. Often, stoichiometric reactions with quantitative yields of the final product are possible, rendering the use of solvents and work-up procedures unnecessary [3,15].…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical Knoevenagel condensation investigated in situ

Haferkamp

Fischer

Kraus

et al. 2017

Beilstein J. Org. Chem.

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The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction leads to a quantitative conversion to p-nitrobenzylidenemalononitrile within 50 minutes. The in situ data indicate that the process is fast and proceeds under a direct conversion. After stopping the milling process, the reaction continues until complete conversion. The continuous and the stopped milling process both result in crystalline products suitable for single crystal X-ray diffraction.

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Section: Introductionmentioning

confidence: 99%

Mechanochemical Knoevenagel condensation investigated in situ

Haferkamp

Fischer

Kraus

et al. 2017

Beilstein J. Org. Chem.

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“…Actually, many errors in the interpretation of solid-state reactions derive from falsely calling them "mechanochemical" (for example [6] and many other publications). Recent reviews dealing correctly with that distinction are in [8][9][10][11]. Figure 7 points out the difference.…”

Section: Resultsmentioning

confidence: 99%

“…It is proven by ample AFM results without milling/grinding and by the multitude of unbeatable solid-state reactions. Unsuitable crystal packing in the absence of voids, channels, or slip planes can often be engineered with different polymorphs, salt formation, and the like [1,8,16].…”

Section: Resultsmentioning

confidence: 99%

“…These features are unbeatable and the results cannot be topped. But despite several exhaustive reviews [1,[8][9][10][11] and despite covering virtually all reaction types, these and the original publications are not cited, discussed, and compared in "green publications" with their poor results, when deviations from the state-of-the-art are tried by (often purposeful) creation of melts, due to not taking care of temperature control upon milling. In addition to that, others have been trying with addition of "a little solvent" [6], or with too high impact that clogs the materials to the walls.…”

Section: Discussionmentioning

confidence: 99%

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More than Thousand Quantitative Wasteless Syntheses in 25 Reaction Types all Across Molecular Chemistry

2017

JPR

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Wasteless preparative molecular and ionic solid-state reactions (gas-solid and solid-solid) proceed rapidly, with definite completion, at decreased activation energy omitting catalysis and waste-producing chromatographic workup, when properly executed. They are unbeatably specific, scalable up to industrial production, and obtain otherwise not available compounds also directly pure. The already available more than thousand 100% yield reactions in 25 reaction types (not counting subdivisions) across molecular chemistry are unfortunately mostly not cited, discussed, or compared in the inferior publications that depart from the solid-state and discredit the field by extremely long milling times, unnecessary catalysis, incomplete reactions, low selectivity, chromatographic workup, etc. Thus, the lack of temperature control and/or the retrogressive adding of “a little solvent” for synthetic milling leads to melt reactions at rapidly increasing temperature (most severe with planetary mills), losing all the benefits of the molecular solid-state. It is recapitulated how the solid-state can be retained with simple means, how Schmidt’s topochemical hypothesis (“forbidding” these unbeatable solid-state syntheses) is overcome, and what the physical reasons are for long range anisotropic molecular migrations along crystallographic channels, cleavage planes, or to voids. It is again shown that local melting is not required. Staying below the lowest eutectic temperature is essential. The basic reasons and technical requirement for the wealth of thermodynamic controlled solid-state reactions (as opposed to counter-thermodynamic mechanochemistry) are summarized in this mini review with a short selection from the striking synthetic advancements to remind the mostly disregarded top of sustainability also against some habits with the 12 commandments of “green chemistry”. These do not require avoiding unnecessary catalysis (on the contrary) or solvents (“green solvents” are also deactivating), or to completely avoid (instead of “decrease”) dangerous wastes by solvent consuming chromatographic workup, etc. This holds for particularly easy gas-solid productions and to solid-solid reactions, where mills are presently often misused heating/melting devices.

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“…Organic mechanochemical reactions (more than 1000 stoichiometric reactions have been recorded) can proceed with 100% yield and do not require purifying workup, they are solvent-and waste-free [105] . This aspect is very tempting for the industry; as the consequence, some of these reactions were successfully scaled up using industrial mills.…”

Section: Mechanochemical Reactionsmentioning

confidence: 99%

Mechanochemical Preparation and Structural Characterization of Layered Double Hydroxides and their Amino Acid-Intercalated Derivatives

Ferencz¹

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Organic Solid-State Reactions

Cited by 17 publications

References 238 publications

Mechanochemical Knoevenagel condensation investigated in situ

Mechanochemical Knoevenagel condensation investigated in situ

More than Thousand Quantitative Wasteless Syntheses in 25 Reaction Types all Across Molecular Chemistry

Mechanochemical Preparation and Structural Characterization of Layered Double Hydroxides and their Amino Acid-Intercalated Derivatives

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