Complex Investigation into the Abrasion-Reaction Modification of Quartz Particle Surface by Amorphous Iron Compounds

Уракаев, Ф. Х.; Ketegenov, T. A.; Petrushin, E. I.; Savintsev, Yu. P.; Tyumentseva, O. A.; Чупахин, А. П.; Шевченко, В. С.; Yusupov, T. S.; Болдырев, В. В.

doi:10.1023/b:jomi.0000013790.50019.c5

Cited by 16 publications

(16 citation statements)

References 21 publications

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“…Possible iron forms in some specimens (e.g. in quartz particles) were determined by acid etching of the material according to 33) . Washed samples were studied by routine analysis methods.…”

Section: Product and Process Characterizationmentioning

confidence: 99%

“…1), we also used an AGO-2 mill and fused quartz (from the standpoint of interpretation of XRD data, amorphous materials are the most suitable abrasive components). It follows from 33) that ~90% of iron is present in quartz in an acid-soluble (metallic and magnetic) form. The total wear of steel mill fittings can amount to ~5% (~7 g), and the dependence of the amount of worn iron on the time of processing is not linear (Fig.…”

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

“…The deviation from linearity is caused by the self-lining of milling tools to a degree that increases as the specific surface area of the material under . processing grows 33,46) . This partially protects milling tools from wear.…”

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

“…This partially protects milling tools from wear. Temperature and pressure pulses 2,3,7) favor the occurrence of chemical reactions involving the material of milling tools, substance being processed, and medium 33,34) . As the reaction between Fe and SiO2 is forbidden, we consider the possibility of steel oxidation by air; the drums of our mill did not have vacuum gaskets, and processing occurred under air access conditions, as distinguished from control tests with the AGO-2.…”

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

“…3). The mechanism of the transition to the amorphous state and the thickness of the amorphous layer have long been the subject of discussions 1,33,34) .…”

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

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Phenomenology, Kinetics and Application of Abrasive-Reactive Wear during Comminution (Overview)

Уракаев

Шевченко

2007

KONA

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Valuable information on the phenomenology of mechanical activation will be obtained from the accurate characterization of wearing processes that take place within mechanochemical reactors. Favoring the contamination of reactant powders with material from a reactor s debris, for a long time such processes represented one of the greatest limitations to practical mechanochemistry applications. We will focus on two related aspects of mechanochemical processing by grinding in a ball mill: (i) nanoscale wear of the treated substances and of the milling tools (balls and container wall); and (ii) deposition of a powder coating on the surface of the milling tools (self-lining phenomenon). A new technology called abrasive-reactive wear (ARW) has been developed that utilizes wear debris as an integral component of the reaction system rather than treating it as a harmful impurity. This technology is applied to the preparation of nanocomposites and to the processing of mineral raw materials and industrial byproducts. This review includes preparation experiments, material characterization, ARW kinetics and simulation. Besides developing new technologies, ARW will contribute to a better understanding of the mechanochemical or mechanical alloying process in general.

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Section: Product and Process Characterizationmentioning

confidence: 99%

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

“…3). The mechanism of the transition to the amorphous state and the thickness of the amorphous layer have long been the subject of discussions 1,33,34) .…”

Section: Arw Processes Caused By the Ma Of Quartzmentioning

confidence: 99%

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Phenomenology, Kinetics and Application of Abrasive-Reactive Wear during Comminution (Overview)

Уракаев

Шевченко

2007

KONA

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An Inexpensive and Recyclable Silver‐Foil Catalyst for the Cyclopropanation of Alkenes with Diazoacetates under Mechanochemical Conditions

et al. 2015

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The diastereoselective cyclopropanation of various alkenes with diazoacetate derivatives can be achieved under mechanochemical conditions using metallic silver foil and astainless-steel vial and ball system. This solvent-free method displays analogous reactivity and selectivity to solution-phase reactions without the need for slow diazoacetate addition or an inert atmosphere.The heterogeneous silver-foil catalyst system is easily recyclable without any appreciable loss of activity or selectivity being observed. The cyclopropanation products were obtained with excellent diastereoselectivities (up to 98:2 d.r.) and in high yields (up to 96 %).The transition-metal-catalyzed decomposition of diazoacetates has been used in various synthetic strategies to afford natural products and other biologically active compounds, many requiring high enantioselectivity.[1] Thec atalytic intermolecular [2+ +1] cyclopropanation of alkenes in the presence of diazoacetates is awell-studied transformation that is often used as ab aseline reaction for testing the activity and selectivity of newly developed catalysts.[2] Whereas several transition-metal salts have been shown to be catalytically active for the cyclopropanation of alkenes in the presence of carbene precursors,dirhodium(II) salts are widely recognized as the benchmark catalysts for these transformations as they enable the cyclopropanation of aw ide range of substrates with high chemo-, regio-, and stereoselectivity.[3] At the same time,asignificant financial cost is incurred by these preciousmetal catalysts.T oa lleviate some of the economic concerns associated with homogeneous catalysts,s everal reports have sought to immobilize them on as olid support to render the catalysts recoverable and recyclable for future use.[4] Still, multistep ligand syntheses and the cost of the solid support place an additional burden on yielding ah igher catalytic activity (e.g.,improved turnover numbers and frequencies) to recover the initial cost of investment. Furthermore,o ver the catalyst lifetime,r hodium metal is leached from the solid support into the product mixture,a nd the support must be continually charged with additional catalyst, which constitutes an additional expense to the operation costs.[5] Alternatively,r eplacing precious-metal catalysts with more earthabundant materials would have many wide-ranging benefits for developing sustainable processes.T owards this goal, Pericàs and co-workers have developed ap olystyrene-supported tris(triazolyl) methyl copper(I) complex for carbene transfer reactions of ethyl diazoacetate to aw ide range of organic compounds both in batch and in continuous-flow setups.[6] More recently,J ones,D avies,a nd co-workers also developed af low reactor system for highly enantioselective CÀHi nsertion reactions with immobilized chiral dirhodium salts. [7] Tr ansition-metal-catalyzed reactions under mechanochemical conditions have been shown to have many advantages over traditional solution-based methods.[8] Furthermore, many research groups...

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An Inexpensive and Recyclable Silver‐Foil Catalyst for the Cyclopropanation of Alkenes with Diazoacetates under Mechanochemical Conditions

et al. 2015

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show abstract

Complex Investigation into the Abrasion-Reaction Modification of Quartz Particle Surface by Amorphous Iron Compounds

Cited by 16 publications

References 21 publications

Phenomenology, Kinetics and Application of Abrasive-Reactive Wear during Comminution (Overview)

Phenomenology, Kinetics and Application of Abrasive-Reactive Wear during Comminution (Overview)

An Inexpensive and Recyclable Silver‐Foil Catalyst for the Cyclopropanation of Alkenes with Diazoacetates under Mechanochemical Conditions

An Inexpensive and Recyclable Silver‐Foil Catalyst for the Cyclopropanation of Alkenes with Diazoacetates under Mechanochemical Conditions

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