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 Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>