Reactive Dry‐Milling for Environmental Protection Encouraging Industrial Applications for High Kinetic Processing

Kaupp, Gerd; Naimi‐Jamal, M. Reza; Ren, Honglei; Zoz, H.

doi:10.1002/chin.200437274

Cited by 9 publications

(18 citation statements)

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“…Without heating of the mill, the milling times (1 a-h, p-q, x) ranged from 1 to 2 h. This result underlines the superiority of the heating/cooling device of the mill. [1,2,4,28] Melting points and spectral data of the reaction products 5 corresponded well with the literature values. [14] Importantly, no decomposition of the oxime hydrochloride products occurred under the specified conditions and this technique gave superior results to previous examples.…”

Section: Oximes By Solvent-free Kneading Ball-millingmentioning

confidence: 55%

Kneading Ball‐Milling and Stoichiometric Melts for the Quantitative Derivatization of Carbonyl Compounds with Gas–Solid Recovery

et al. 2009

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A ray of hope for the environment is sustainable and green synthesis without the production of (toxic) waste. Solvent-free stoichiometric melting or kneading ball-milling reactions of aldehydes or ketones with carbonyl reagents yields arylhydrazones and oximes in quantitative yield. The carbonyl compounds can be quantitatively recovered from the imino derivatives by using gaseous NO(2).An effective methodology of kneading with a ball mill under temperature control was used for the stoichiometric quantitative preparation of synthetically versatile oximes and 2,4-dinitrophenylhydrazones from low-melting aldehydes and ketones. Also, a large number of phenylhydrazones are obtained by safe stoichiometric quantitative melt reactions. Advantages of this technique are short reaction times, eco-friendliness, and ease of handling under solvent-free conditions, as no waste-producing purifying workup is necessary. The different reactivities of aldehydes and ketones allow for easy separation of mixtures containing aldehydes and ketones. Furthermore, a new effective, gas-solid deprotection methodology for oximes was developed, using nitrogen dioxide as the reagent under solvent-free conditions to recover the aldehydes or ketones. The corresponding aldehydes were obtained free of overoxidized acids in quantitative yields.

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Section: Oximes By Solvent-free Kneading Ball-millingmentioning

confidence: 55%

Kneading Ball‐Milling and Stoichiometric Melts for the Quantitative Derivatization of Carbonyl Compounds with Gas–Solid Recovery

et al. 2009

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“…Temperature control of the larger mills (≥ 2 L) is by cooling with cooling mantels and automatic alternating milling with cooling cycles using the different processing state. Since several hundreds of waste-free solid-solid syntheses have been reported in the exhaustive review [4] we select here the already realized large-scale examples of solid-solid molecular reactions [24]. Figure 15 contains two examples of unbeatable stereo specificity.…”

Section: Catalysed Reactions Cascade Reactionsmentioning

confidence: 99%

How are Waste Entirely Avoided in Solid-State Productions?

Kaupp¹

2017

J Chem Eng Process Technol

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The mechanism, synthetic application, scaling, and industrial production with gas-solid and solid-solid reactions without producing wastes is outlined. These reactions profit from lowered activation energy (with respect to melt reactions), favorable kinetics with definite end of reaction, and mostly reaction specificity giving only one product in pure form without workup necessity. They proceed thus solventless (not only "solvent free") and wasteless. The bargain of the solid-state should not be given up by heating to melt (e.g., milling without temperature control) or by "adding a little solvent". Molecular (or ionic) solid-state reactions, be they gas-solid or solid-solid, profit from the presence of cleavage-planes, channels or voids for intracrystalline long-range anisotropic molecular migrations. Such release of internal local pressure upon chemical change is essential. This is experimentally verified. In the solidsolid case mixing and contacting leads to the thermodynamically more stable product, but this does not exclude kinetic control. It is of utmost importance to control the temperature so that eutectic temperatures (melts) are not reached during all reaction stages. Typical examples out of more than already thousand 100% yield reactions from 26 reaction types for particularly delicate (not otherwise available) or otherwise interesting products are presented, and the scaling up to continuous industrial production is exemplified. Also, mechanochemical reactions (for example counter-thermodynamic mechanical bond breaking of infinite covalent materials) can be waste-free, ending with the most stable possibility when the bond-breaking ceases at the nanoscale. The proper experimentation (most important is strict temperature control) is outlined and easily and safely achieved.

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“…For complete solid-solid reactions with 100% yield in stoichiometric mixtures, ball-milling is the first choice [3,[6][7][8][9]. If double-walled milling chambers are used the possibility of cooling/heating can be used which appears quite important.…”

Section: Experimental Techniquesmentioning

confidence: 99%

“…As ball-milling of molecular crystals or salts [9][10][11] does not induce "mechanochemistry" (breaking of regular molecular bonds cannot occur, with the exception of weak bonds of explosives, but intermolecular interactions and van der Waals attractions or H bonds can be broken, and the surface is increased by crystal disintegration), the moderate efficiency of swing-mills with a cooling/heating device is sufficient [3,12]. High milling efficiency in rotor-mills for larger-scale milling (up to the kilogram scale and beyond) [6][7][8] increases the contact rate. It is also essential for tribochemistry (mechanochemistry if strong s bonds in polymers or infinite covalent crystals are broken with formation of local plasma at the freshly broken crystal surfaces, for example at silica or silicon) with totally different reactivities in plasma chemistry with virtually all kinds of organic additives [6,8] which, however, is not the subject of this review.…”

Section: Experimental Techniquesmentioning

confidence: 99%

“…High milling efficiency in rotor-mills for larger-scale milling (up to the kilogram scale and beyond) [6][7][8] increases the contact rate. It is also essential for tribochemistry (mechanochemistry if strong s bonds in polymers or infinite covalent crystals are broken with formation of local plasma at the freshly broken crystal surfaces, for example at silica or silicon) with totally different reactivities in plasma chemistry with virtually all kinds of organic additives [6,8] which, however, is not the subject of this review.…”

Section: Experimental Techniquesmentioning

confidence: 99%

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