Two disciplines: chemistry and chemical engineering matter together (Day 364)
26th May 2015
Today is Day 364, the penultimate day of my blog and just two days left to shine a light on chemical engineering.
So I want to take the opportunity to talk about the important relationship between chemistry and chemical engineering before time runs out on ChemEng365.
However, it is also important to note that chemistry and chemical engineering are interdependent and must work together. I have made it part of my focus as president of IChemE to build further on our strong relationship with the Royal Society of Chemistry (RSC).
I am proud to have started out my career studying chemistry at the University of Oxford, UK, however, I am also now proud to be a chemical engineer and to have spent my presidential year promoting the fact that chemical engineering matters.
But let's not forget that chemistry matters too.
So I'm going to use today’s blog to highlight two world-changing collaborations between chemists and chemical engineers, which illustrate the importance of the relationship really is.
1. Penicillin
But it was World War Two (WWII) and the D-Day landings in 1944, which first saw this drug deployed on a massive scale. I discussed this in an earlier blog: D-Day - a day chemical engineers should remember.
While many people worked on scaling up the production of penicillin, it was a Pfizer chemical engineer, John McKeen, and his chemist colleague, Jasper Kane, who made the biggest contribution. John and Jasper cracked the production problem via deep-tank fermentation.
The early work in trying to scale up penicillin was carried out in the UK, by companies such as Glaxo and Boots, through surface fermentation. Producing chemicals through fermentation was a new method and was very inefficient. To improve the methodology, more government funding was required. But WWII had been going on for some time and the money was not available in the UK. Thus the research was handed over to the US, who did have the funding, to move the technology forward.
Mass production of penicillin was a major challenge. The US company Pfizer was struggling to produce sufficient supplies to the anticipated casualties. To quote a Pfizer plant manager: “The mould is as temperamental as an opera singer, the yields are low, the isolation is difficult, the extraction is murder, the purification invites disaster and the assay is unsatisfactory - Is it worth it?”
John and Jasper’s contribution was the industrial-scale production of penicillin via deep-tank fermentation. Without it, penicillin would have remained a laboratory curiosity, restricted to the lucky few.
Deep-tank fermentation was already happening in the US; Jasper had worked on a previous project at Pfizer to produce citric acid for food products through this process. John was tasked with the role of setting up a pilot plant for penicillin, initially he started with surface fermentation but soon realised this would not work efficiently enough. Jasper suggested the use of deep-tank fermentation from his previous experience.
And the rest is history. Their collaboration was well worth it. Thousands of lives were saved and as production was increased, the cost dropped from nearly priceless in 1940 to 50 cents per dose by 1946.
2. Fertiliser
Fritz Haber, a chemist, worked out how to take nitrogen from the air and convert it to ammonia and Carl Bosch, a chemical engineer, then handled the scale up of this process and made the manufacture of synthetic fertilisers possible. Today, the fact that the world can support seven billion people is down, in large part, to the Haber-Bosch process.
With the advent of the industrial age and the great migration to the cities, fertilisers were essential for topping up soil with nutrients. Natural fertilisers such as Chilean guano were a limited resource so if science didn’t come to the rescue, famine was certain to follow. Fritz Haber was one of a group of chemists, that also included Walther Nernst and Henry Le Chatelier, who had decided to tackle the problem.
Fritz initially attempted to produce nitric oxide with the help of electric discharges, mimicking natural processes during a thunderstorm. But the yield was so low and the process so onerous that it was dismissed as impractical.
It was not until 1908 that Fritz, working with his student, Robert le Rossignol, decided to tackle the high-pressure route. It was a good choice. One year on, they patented a process that yielded some 15 per cent ammonia, operating at a pressure of around 175 atmospheres at 550ºC over an osmium and uranium catalyst.
The process was soon assigned to Badische Anilin und Soda Fabrik (BASF), which tasked chemical engineer Carl Bosch with scaling up the process.
Carl later said: “It was obvious that there were three main problems which had necessarily to be settled before the construction of a plant could be undertaken. These were supply of raw materials, ie of the gases hydrogen and nitrogen, at a lower price than hitherto possible; the manufacture of effective and stable catalysts; and lastly the construction of the apparatus.”
Carl believes his greatest feat was solving the third problem; how to build a reactor that would withstand both the high temperatures and high pressures of the reaction. High pressure chemistry was still a very new field, and suitable equipment was in short supply. First Carl had to devise a new laboratory reactor, for which he re-modelled Fritz’s original design into a robust, reliable reactor.
The first plant to use the Haber-Bosch process at industrial scale started up at BASF Oppau in 1913. Nearly 100 years on nothing much has changed – the process is still used around the world today.
We must live within the boundaries set by our ecological life support system. Perhaps the next big chemistry-chemical engineering collaboration can help solve the problems of an expanding population.
Chemistry needs chemical engineering and vice-versa. We are better placed to confront the challenges of the 21st Century by working together and I have one foot firmly placed in both disciplines
If you have a story you would like to share about an excellent collaboration, why not get in touch and tell us all about it?