Chemical Communications Blog

A hydrazine-based ionic liquid could be used as rocket fuel, say US scientists.

The combustibility of ionic liquids, a hazard for most applications, has inspired researchers to consider them as possible propellants in rocket fuels. Robin Rogers and his colleagues from The University of Alabama in Tuscaloosa and C3 Propulsion in Huntsville have found that an ionic liquid based on one of the most widely used rocket fuel propellants, hydrazine, ignited on contact with a catalyst, without the need for an oxidant or an ignition source.

The team studied the behaviour of nitrate salts of 2-hydroxyethylhydrazinium upon addition of various catalysts. It was found that in the presence of one particular solid catalyst, Ir-alumina (known as Shell 405), and at temperatures above only 100 °C, the salts ignited, producing smoke and gas.

Addition of 2-hydroxyethylhydrazinium dinitrate to the solid catalyst Shell 405, followed by smoke, flame and residual catalyst

Rogers explains that the impetus for the research was increased safety: ‘we wanted to see if we could take a hydrazine-like molecule, which is volatile, turn it into a non-volatile salt and yet still have the same reactivity that the hydrazine did. We were pretty excited because it worked.’

In addition to decreasing vapour toxicity by replacing hydrazine with an ionic liquid, this material could lead to safer, more efficient, forms of rocket fuel since ignition could occur simply by running the ionic liquid over a catalyst bed, eliminating the need for stabilisers or an additional liquid oxidant.

‘Clearly, this is not only a safer way of propellant ignition, it is also more effective as it allows for low temperature combustion,’ says Christopher Hardacre, an expert in ionic liquids and catalysis from Queen’s University Belfast in Northern Ireland. Hardacre adds that the low volatility associated with ionic liquids as well as the low cost of the materials makes this propellant system even more attractive for various applications.

The work is still in its infancy and the next step will be to optimise the material for specific applications. ‘We need the real rocket scientists out there to weigh in and tell us what needs to be improved or to find better molecules or better salts,’ says Rogers.

Patricia Pantos

For more information, download Rogers’ ChemComm communication.

Finally, the wait is over – ChemComm issue 1 has arrived and it does not fail to disappoint! It is bursting at the seams, filled with some truly outstanding Feature Articles and Communications from emerging scientists from across the globe, all of whom are in the early stages of their independent careers.

So why not take a look at issue 1 today? It is available to view online and all the articles will be free to access until the end of 2011. If you would like to be considered for next year’s issue (2012) then please email the ChemComm Editorial Office expressing your interest.

We are also pleased to announce that this ‘Emerging Investigators issue’ has also been recognised as an official activity for celebrating the International Year of Chemistry (IYC) during 2011. Why not take a look at the IYC website and keep up-to-date on what else is happening throughout 2011 to celebrate the achievements of chemistry and its contributions to the well-being of humankind.

Great research can start anywhere including your own undergraduate laboratory, as recently demonstrated by scientists in the US. 

Whilst running a teaching laboratory at the Texas Woman’s University, Manal Rawashdeh-Omary had senior undergraduate students attempting to reproduce literature findings published 10 years previously by Rasika Dias (from the University of Texas at Arlington) her collaborator. The students were asked to recreate a trinuclear silver pyrazolate complex, where one group of students obtained the expected non-luminescent dry product, whilst the other attained an unexpected green-luminescent product. Rather than simply dismissing the green product as experimental error, Rawashdeh-Omary directed her research group to investigate the reason for this ‘mistake’.  

(From left to right): Samuel Kiplagat, Tiffany Vaughan, Manal Rawashdeh-Omary, Shylaja Dharanipathi & Jacqueline Washington

The group realised that the green-luminescent complex was actually reacting with benzene – a highly toxic chemical, known for its carcinogenic properties. By incorporating the complex into thin films, the sensor could detect minute amounts of benzene vapour (and other small organic vapours) with remarkable reversibility, selectivity, speed and sensitivity. This is an important development for environmental and health issues, as well as making advancements in fundamental chemical phenomena for donor-acceptor and acid-base chemistry.

It is refreshing to see high quality research coming from universities and departments actively supporting women in science. Texas Woman’s University is the largest university primarily for women in the USA, with over 90% of the undergraduate population being female. Omary explains that many of the staff and students are mothers, balancing their research and studies with family responsibilities. So it is inspiring to learn that top quality research can be produced from all levels of academia and this is a true testament to undergraduates, showing what hard work and dedication can achieve.

Fancy reading more about this on/off benzene sensor? Then why not download the article today, which has been published in ChemComm and will be free to access until the 24th December. 

Written by Edward Morgan