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 Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>