Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Separation by Milling

03.05.2013
How does one separate a mixture of components with very similar properties? In the journal Angewandte Chemie, Croatian researchers have introduced a new approach to the separation of organic compounds.

In their process, a “host compound” recognizes the desired “guest molecules”, not only in solution, but also when the host and mixtures of competitive guest are milled together in the solid state. For the separation of maleic acid, this recognition through mechanochemistry delivers selectivity equal to that achieved by crystallization from a solution.



Mixtures of dicarboxylic acids can be separated through crystallization, rectification, or extraction, processes often pushed to their limits because the dicarboxylic acids being separated have very similar chemical properties. Krunoslav Užareviæ and his co-workers at the Ruðer Boškoviæ Institute and the University of Zagreb have now proposed an alternative method: separation through solid-state molecular recognition. Molecular recognition is the interaction of molecules that “fit” together without chemical bonding.

Such interactions are known from phenomena such as enzyme recognition and DNA base pairing. This principle can also be used for the construction of supramolecular systems for nanotechnology. If one molecule is “lodged” inside another, the system is described as a host–guest interaction. Usually, molecular recognition is accomplished in solution, where the host and guest have the necessary mobility to come sufficiently close to one another and interact.

Separation of dicarboxylic acids by means of a host–guest interaction is challenging because the mixtures include isomers or molecules that are very geometrically similar. This is the case for two important dicarboxylic acids, fumaric acid and maleic acid. Fumaric acid is an intermediate product in the energy metabolism of all cells. It has many applications in the food and pharmaceutical industries. Maleic acid is used in polymer production, dying cotton, and decalcifying agents.

Fumaric acid is usually obtained through the isomerization of maleic acid, which is harmful to health, so all residues of maleic acid must be scrupulously removed from the fumaric acid product.

As the host molecule for their separation, the research team selected a polyamine that consists of two oxygen-containing, six-membered, hydrocarbon rings bound together through a hydrocarbon chain that contains three amino groups. This compound is flexible and can crystallize in different conformations. This host molecule preferentially binds maleic acid. It grabs the maleic acid molecule between its two rings like a pair of tongs.

It also selectively binds maleic acid in an excess of fumaric acid or four other related dicarboxylic acids. What is unusual is that this host–guest interaction works under conventional conditions, that is, when crystallizing the compounds out of a solution; as well as in the solid phase, when the dicarboxylic acid mixture is intensively milled together with the host molecule.

This type of selective binding and separation of guest molecules out of solid mixtures is, with the exception of a few pioneering experiments, a largely unexplored area of research. This work demonstrates that there is a vast potential of the solid-state molecular recognition for more environmentally friendly separation technologies.

About the Author
Dr Krunoslav Užareviæ is a Scientific Associate at Ruðer Boškoviæ Institute in Zagreb. His main scientific interests lie in the study and application of supramolecular chemistry principles for controllable solid-state reactivity and development of “greener” technologies for synthesis and separation.

Author: Krunoslav Užareviæ, Ruder Boskovic Institute, Zagreb (Croatia), http://www.irb.hr/eng/People/Krunoslav-Uzarevic

Title: Dynamic Molecular Recognition in Solid State for Separating Mixtures of Isomeric Dicarboxylic Acids

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201301032

Krunoslav Užareviæ | Angewandte Chemie
Further information:
http://pressroom.angewandte.org
http://www.irb.hr/eng/People/Krunoslav-Uzarevic

More articles from Life Sciences:

nachricht Biofuel produced by microalgae
28.02.2017 | Tokyo Institute of Technology

nachricht Decoding the genome's cryptic language
27.02.2017 | University of California - San Diego

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Existence of a new quasiparticle demonstrated

28.02.2017 | Materials Sciences

Sustainable ceramics without a kiln

28.02.2017 | Materials Sciences

Biofuel produced by microalgae

28.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>