نتایج جستجو برای: mechanochemical

تعداد نتایج: 2381  

Journal: :Journal of colloid and interface science 2004
Ray L Frost Erzsébet Horváth Eva Makó János Kristóf

A comparison is made of the mechanochemical activation of three low- and one high-defect kaolinite using a combination of X-ray diffraction, thermal analysis, and DRIFT spectroscopy. The effect of mechanochemical alteration of the kaolinites is greater for the low-defect kaolinites. The effectiveness of the mechanochemical treatment is represented by the slope of the d(001) peakwidth-grinding t...

2011
Jana Ficeriová Peter Baláž

The intensification of leaching of gold from a waste using mechanical activation (milling in water) and mechanochemical activation (milling in thiourea solution) were studied as the pretreatment steps. The leaching of “as-received“ sample in an acid thiourea solution resulted in 78 % Au dissolution, after mechanical activation 98 % and mechanochemical activation up to 99 % of the gold was leach...

2017
Patrick A Julien Ivani Malvestiti Tomislav Friščić

We provide the first in situ and real-time study of the effect of milling frequency on the course of a mechanochemical organic reaction conducted using a vibratory shaker (mixer) ball mill. The use of in situ Raman spectroscopy for real-time monitoring of the mechanochemical synthesis of a 2,3-diphenylquinoxaline derivative revealed a pronounced dependence of chemical reactivity on small variat...

Journal: :Faraday discussions 2014
Anatoly Politov Olga Golyazimova

The products of mechanical treatment are surface atoms or molecules, substances with a crystal structure different from their initial one (another polymorph, amorphous), point or linear defects, radicals and new chemical substances. It is often assumed, that to increase the yield of the products of a mechanical treatment, it is necessary to increase the treatment time and the mechanical power i...

2014
Takeshi Ohura Yusaku Tsutaki Masato Sakaguchi

The mechanical fracture of polymer produces polymeric free radical chain-ends, by which liner block copolymers have been synthesized. A diblock copolymer of microcrystalline cellulose (MCC) and poly 2-hydroxyethyl methacrylate (pHEMA) was produced by the mechanochemical polymerization under vacuum and room temperature. The fraction of pHEMA in MCC-block-pHEMA produced by the mechanochemical pol...

2012
Pankaj Chauhan Swapandeep Singh Chimni

Ball-milling and pestle and mortar grinding have emerged as powerful methods for the development of environmentally benign chemical transformations. Recently, the use of these mechanochemical techniques in asymmetric organocatalysis has increased. This review highlights the progress in asymmetric organocatalytic reactions assisted by mechanochemical techniques.

Journal: :Chemical communications 2015
D Prochowicz K Sokołowski I Justyniak A Kornowicz D Fairen-Jimenez T Friščić J Lewiński

We demonstrate a mechanochemical strategy that allowed the first successful mechanosynthesis of IRMOFs based on an oxo-centred secondary building unit (SBU). The presented study indicates that controlling the acid-base relationship between reagents is key to mechanochemical synthesis of IRMOFs, revealing a pre-assembled oxo-zinc amidate cluster as an efficient precursor for IRMOF mechanosynthesis.

Journal: :Phlebology 2016
R Bootun T R A Lane B Dharmarajah C S Lim M Najem S Renton K Sritharan A H Davies

OBJECTIVE Endovenous techniques are, at present, the recommended choice for truncal vein treatment. However, the thermal techniques require tumescent anaesthesia, which can be uncomfortable during administration. Non-tumescent, non-thermal techniques would, therefore, have potential benefits. This randomised controlled trial is being carried out to compare the degree of pain that patients exper...

2014
Antonio Perejón Nataliya Murafa Pedro E. Sánchez-Jiménez José M. Criado Jan Subrt María J. Diánez Luis A. Pérez-Maqueda

In this work, a mechanochemical procedure is proposed as a simple and fast method to synthesize pure BiFeO3 perovskite phase as a nanostructured material without the need for purification treatments, while the mechanochemical reaction mechanism has been investigated and correlated with that of the conventional solid-state reaction. Thus, different milling conditions have been used as a tool for...

Journal: :Chemical communications 2012
Vjekoslav Štrukil Davor Margetić Marina D Igrc Mirjana Eckert-Maksić Tomislav Friščić

ortho- and para-Phenylenediamines were desymmetrised and quantitatively transformed into mono- and bis-(thio)ureas or mixed thiourea-ureas through a one-pot mechanochemical click reaction sequence; mechanochemical desymmetrisation proceeds quantitatively without excess reagents and allows the controlled extension of a molecular structure by combining normally competing reactions.

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