There’s little to alert you that the quiet town of Mülheim an der Ruhr, nestled in Germany’s most populated industrial area, is the site of a cauldron for many chemical innovations of major worldwide impact. That cauldron is the Max Planck Institute for Coal Research, the name of which does not do justice to the plethora of discoveries made there over the past century.
Most famously, it is where catalysts were discovered for the atmospheric pressure polymerization of a cornucopia of plastics, launching an explosion of plastic products in the 1950s and garnering then-director Karl Ziegler the 1963 Nobel Prize in Chemistry with Italian chemist Giulio Natta.
It is also where, in the 1970s, researchers found a way to decaffeinate coffee beans using supercritical carbon dioxide instead of methylene chloride—an early feat of green chemistry and an innovation that preserves coffee’s flavors and odors in decaf brews.
But the institute’s first key achievement, and the only one pertaining to its name, is the Fischer-Tropsch process for turning coal-derived carbon monoxide and hydrogen gas into liquid hydrocarbons. Discovered in 1925, the process allows coal-rich but petroleum-poor countries such as Germany to have domestic supplies of liquid fuel.
For those who work at the institute now, the past can be a little intimidating. “People ask us, ‘When is the next big thing coming out?’ ” says Benjamin List, one of five current directors at KOFO, a common moniker for the institute and a short form for the German word for coal research, KOhlenFOrschung. Any scientific establishment “is lucky to have a world-changing discovery once a century,” List says, and KOFO “has had several.”
The institute’s standards remain high. In 2007, the German Council of Science & Humanities assessed all chemistry-related research institutes and university departments in the nation. KOFO was the only institute to get a top score on all five evaluation criteria, which ranged from research quality to the training of young researchers.
As the institute fetes 100 years of existence—it opened its doors on July 27, 1914—a number of events will delve into KOFO’s past and celebrate its present research, which now spans a range of catalysis science.
The institute’s existence has everything to do with Emil Fischer, who won the 1902 Nobel Prize in Chemistry for work on purine and sugar synthesis. As the first German to win a Nobel Prize, “he had political influence with the German emperor, Kaiser Wilhelm II,” says Alois Fürstner, another KOFO director. “He was Germany’s best-known chemist.”
In 1911, Germany’s emperor began establishing university-independent research centers, called Kaiser Wilhelm Institutes, where top-notch scientists could focus on their work without the need to apply for funding or to teach. (They were renamed Max Planck Institutes after World War II.) In 1912, Fischer gave an influential speech arguing the need for an institute focused on catalysis: “Nature has not treated Germany generously with respect to liquid fuel such as petroleum,” he said. “How satisfying it would be if solid fuel could be converted economically into liquid fuel by a suitable reduction process.”
Founders probably included “coal” in the new institute’s name to get local financial support from coal-mining companies in the Mülheim region, Fürstner says. But aside from the token name, coal companies had little control over the kind of research taking place at the institute.
Emil Fischer also proposed that the director of this institute should be the physical chemist Franz Fischer (no relation), who according to a 1982 KOFO institutional history, confessed on his first day that he “didn’t understand anything about coal.”
Despite KOFO’s inauspicious launch—World War I started the day after the institute opened, and many researchers were sent to the front—choosing Franz Fischer to lead the institute achieved Emil Fischer’s liquid-fuels goal. In 1925, Franz Fischer and his colleague Hans Tropsch figured out how to make long-chain hydrocarbons from coal-derived carbon monoxide and hydrogen gas using a solid catalyst composed of either cobalt or iron.
Over the next decades, this process became extremely useful to many petroleum-poor countries. By the early 1940s, some 600,000 metric tons of liquid fuel were being made through the process, particularly in Germany, which had been cut off from many raw materials because of Allied embargoes. The process continues to be used—albeit to a lesser degree—at power plants and factories around the world, in places such as South Africa, Finland, and Qatar.
In 1943, Fischer retired as KOFO’s director, while Germany was in the full throes of World War II. In his stead, Ziegler, a world-renowned organometallic chemist at the University of Halle, was offered the job.
Until the end of the war, Ziegler maintained a lab in Halle, 250 miles east of Mülheim. This was because the industrial region around KOFO was under heavy Allied bombing and because Ziegler was involved in a military explosives research project in Halle, explains Henrik Eberle, a historian at Martin Luther University of Halle-Wittenberg. Ziegler “was certainly a German patriot,” Eberle notes, “but he certainly wasn’t an ardent Nazi.” Ziegler came under criticism in 1936 from Nazis for associating with Jewish colleagues. He points out that Ziegler did not join the Nazi Party, but he did contribute a few German marks a month to the SS, the Nazi paramilitary organization.
At the end of the war, U.S. troops temporarily detained Ziegler and his laboratory colleagues, probably in an effort to assess his scientific work and ensure it did not fall into the hands of the advancing Russians, Eberle notes.
After the war, Ziegler moved permanently to Mülheim. In his 1963 Nobel lecture, he noted that his group’s subsequent research at the institute “resembled a meandering through a new land. ... I never had the slightest notion that successful technological and industrial applications were also to be encountered during the journey.”
In 1953, when Ziegler and his colleagues discovered the catalysts that would help make plastic a ubiquitous material around the world, they were trying to understand what appeared to be an unexpected reaction artifact, says Walter Thiel, a KOFO director and theoretician. “Ziegler did not disregard the result. He followed through, trying to get to the bottom of it,” Thiel adds.
In doing so, Ziegler and colleagues discovered a suite of catalysts that could polymerize ethylene and propylene at much lower pressures than existing methods. Their catalysts also created polymers with less branching, leading to plastics that performed better at high temperatures and were also more rigid than previous ones.
Within a decade, factories around the world were producing hundreds of thousands of metric tons of plastics using Ziegler catalysts. Meanwhile, patent proceeds flooded into KOFO coffers, allowing the institute to become entirely financially independent from Max Planck Society-orchestrated government funding. During the 40-year golden era—until the patents expired in the 1990s—top-of-the-line equipment could be bought without a second thought, and smart researchers would be invited to spend time at the institute to work on their scientific whims.
It’s during this flush time, for example, that one of the institute’s employees, Kurt Zosel, spent a few years tinkering with supercritical carbon dioxide, a fluid state of the normally gaseous compound. Zosel figured out the conditions for using supercritical carbon dioxide to remove caffeine from green coffee beans. By the early 1980s, the method was licensed. It is now the industry-standard decaffeination process.
But to keep the Ziegler patent proceeds flowing into KOFO so that all manner of research could be pursued at the institute, Heinz Martin, one of the chemists who had worked on the original Ziegler catalysts, became a full-time monitor of patent infringement. That’s a transgression U.S. companies were particularly guilty of, says Günther Wilke, who succeeded Ziegler as KOFO’s third director in 1969 and who did pioneering work in dimerization and trimerization of butadiene to make starting materials for polymers used in soccer shoes, car interiors, and other products. “Between 1972 and 1990, the institute won $100 million in lawsuits,” Wilke says.
“All the major chemical companies would use Ziegler catalysts and would say, ‘We have an in-house method,’ ” List says. But there’s always a little bit of catalyst in the polymer: It’s a smoking gun for the process. So Martin would buy plastics from all over the world and measure the entrapped catalyst, proving that the polymers had been made using the Ziegler method, Wilke adds.
The last of the Ziegler patents ran out in 1995, two years after Wilke retired as director. Manfred T. Reetz, the institute’s fourth director, was then charged with orchestrating a new funding model. It included government support through the Max Planck Society and funds from a foundation established by Ziegler that currently accounts for about 16% of KOFO’s $37 million annual budget, supporting a staff of 350.
“My idea for the institute’s future was to have all types of catalysis under one roof—heterogeneous, homogeneous, and organometallic catalysis—as well as theory and synthesis,” Reetz says. It took Reetz four years to convince the board of governors that a monolithic structure under one director was not the path for the future and that it was better to have five independent departments headed by directors with equal power—with, of course, the Max Planck model of no-strings-attached funding.
Fürstner and Ferdi Schüth arrived in 1998 to lead the organometallic and heterogeneous catalysis departments, respectively. In 1999, Thiel established the theory department, and in 2005 List took over the homogeneous catalysis department. Reetz used his directorship to begin working on directed evolution. “I had never touched an enzyme before I came to Mülheim,” Reetz says, but he is now well-known as a pioneer in the directed-evolution field. Reetz has since become an emeritus director because of retirement rules, but he maintains an active group at the University of Marburg, funded by the Max Planck Society.
A new director to replace Reetz will likely be announced later this year, but the institute’s name will remain the Max Planck Institute for Coal Research, despite the fact that “nobody here is actually doing coal research,” List says. “We keep the name because of tradition,” he adds.
“Coca-Cola doesn’t contain cocaine anymore,” Reetz points out. But company officials “haven’t changed its name.”
“We see our name as a brand,” Fürstner says. “You don’t change a brand name.”