Makoto Misono

A research profile of a leading Japanese green chemist

Personal summary

Makoto Misono was born on 1 March 1939 in Kagoshima (Kyushu Island), Japan. At the age of seven, after a few years in Taiwan and Yamaguchi, he moved to Tokyo. Since then he has lived in Tokyo, except for 28 months in the USA. Married in 1970 to Yoshiko, he has two daughters.

Career

Misono graduated from the Department of Applied Chemistry, University of Tokyo, in 1961 with a Bachelor’s degree and obtained his Master′s degree (1963) and Doctorate (1966) in engineering from the same university. He started his academic carrier as a research associate of the university in 1966 and was promoted stepwise to a full professor in catalytic chemistry in 1983. In 1999, he retired with an Emeritus professorship and became a professor at the Department of Environmental & Chemical Engineering at Kogakuin University (located in Shinjuku, the busiest district of Tokyo). He was elected a member of the Science Council of Japan in 2000 and recently was elected the President of the Chemical Society of Japan for 2004.

From 1967 to 1969, Misono stayed in the USA as a postdoc, one year at University of California, Santa Barbara (with Professor P. W. Selwood) and another year at the Mellon Institute, Pittsburgh (with Dr. W. Keith Hall). In addition, he spent two months in 1996 as an Ipatieff Lecturer at Northwestern University, USA, and a month as a Professor Emeritus at Litoral University, Argentina.

From 1995–1998 Misono ran a project on catalysts of unique reaction fields (environmental and microporous catalysts) which was funded (0.7 billion ¥) by the Ministry of Education. He is now (2002–2007) a project director of the nano-structured environmental catalyst program within the 3 billion ¥ Governmental Nanotechnology initiative.

Research

Makoto Misono started his research in 1960 in the field of heterogeneous catalysis. The study of engineering sciences (or design-oriented sciences) has been a research focus throughout his career, but his research interests have changed somewhat to reflect the rapid growth and subsequent decline of heavy industries in Japan. First he worked on catalysts for the petrochemical industry and, after several oil crises, on more fundamental studies, as well as environment- and energy-related catalysts, as described below. He is no longer directly involved in experimental research, but is involved mainly in environment-related issues such as green/sustainable chemistry, clean fuels, alternative energies, and automobile emission control in both academic and government circles.

Misono’s earliest research was on solid acid catalysts to find correlations between catalytic performance and the acidity of catalysts. His first paper was about in situ measurement of the acidity of silica–alumina and was presented at the Third International Congress on Catalysis (3 ICC) at Amsterdam in 1964. The strong dependency of catalytic activity on acid strength was demonstrated. Then he attempted to elucidate the relationships between acid strength and catalytic performance. He found good correlations for catalytic activity (oligomerization of propene), and selectivity (isomerization of butenes). He also proposed parameters for soft and hard acids and bases, referring to several data books. This time-consuming work broadened his view of chemistry. His major background is physical chemistry for industry, so the underlying principle was to find general rules for catalyst design, in particular, to establish the following three relationships (eqn. 1):

Catalytic performance ⇔ Chemical and physical properties ⇔ Composition and structure ⇔ Method of syntheses (1)

In this period, the first relationship of eqn. 1 was focused as directed by his supervisor. Later, stress was also placed on the second and third relationships, noting the variety and diversity of chemistry.

Misono′s studies during his postdoc were also on heterogeneous catalysis, but with different aims. In a small laboratory at Santa Barbara, USA, he discovered the effect of a magnetic field on o- to p-conversion of hydrogen. Under an extrinsic magnetic field, the reaction over ruby powder or chromia was accelerated or suppressed significantly depending on the temperature and the magnitude of the magnetic field. This phenomenon was not expected from the conventional theory and was hence called, for a while, the ‘Misono–Selwood effect.’ The effect was suggested to be the origin of the ability of migratory birds to find their direction (Selwood, Nature, 1970).

In Pittsburgh, reduction and oxidation of copper in hydroxyapatite was studied in an orthodox way. Reduction by hydrogen took place for diluted copper as follows: atomic Cu(2+) → atomic Cu(+) → Cu(0) cluster, and, upon re-oxidation, Cu(0) → Cu(2+) oxide → atomic Cu(2+). Cu(+) was most active for H₂–D₂ isotopic equilibration.

Misono learned some valuable things in the USA:

• the presence and influence of a different culture in both daily life and the way in which research is conducted

• the importance of stoichiometry in chemistry

• the vital importance of originality in research

After he returned to Tokyo, Misono slowly restored the importance of research, at a time when student movements in the late 1960s were still active. He found distinct relationships between acid–base properties and the selectivity and stereochemistry for dehydrohalogenation of haloalkanes and became productive in the publication arena. Rational interpretation for the above relationships was given based on the detailed mechanism elucidated by tracer studies and quantum chemical calculations.

At that time, the chemical industry suffered from pollution problems, and chemical technology was criticized by the public. As he was conscious of these issues, Misono thought that new approaches and new catalytic technology were needed and hence started two research projects on mixed oxides.

From the beginning, he placed a strong emphasis on catalyst structure and preparation, i.e. the second and third relationships in eqn. 1, in order to form scientific basis for industrial catalysts. He set up several criteria to choose appropriate catalyst materials to study:

• the structure of catalysts must be well characterized, at least for the solid bulk

• the composition and hence the chemical properties must vary across a wide range by substitution of constituent elements, maintaining the bulk structure

• the catalytic performance must not be far from the level required for commercialization

According to these criteria, crystalline mixed oxides such as heteropoly compounds (or polyoxometalates), perovskites, V–P–O, and a few more compounds have been chosen since the mid-1970s. The study started with the elucidation of bulk structure, in particular, with the confirmation of molecularity of solid heteropoly compounds, followed by the measurement of chemical properties and catalytic performance. Many unexpected phenomena that convinced him of the wonder and depth of chemistry came across in this period. The findings of hierarchical structure and the three types of catalysis for solid heteropoly compounds, he believes, have provided the sound basis of catalyst design of heteropoly compounds at the molecular level (Chem. Commun., 2001, 1141). The presence of bulk-type catalysis (e.g., ‘pseudoliquid’ behavior) is very unexpected, and the idea solved several puzzles present at that time in the literature. These achievements were presented as a plenary lecture at the 10th International Chamber of Commerce (ICC) World Congress in Budapest in 1992. Several large-scale chemical processes were industrialized in Japan utilizing heteropoly compounds, although Misono’s contribution was only to basic understanding. Most of these processes are very green (Misono et al., Pure Appl. Chem., 2000).

The second subject, i.e. environmental catalysis, was chosen to publicize the usefulness of catalysts to the general public. A perovskite catalyst was commercialized for the suppression of smoke and cooking smells in kitchens; 50,000 of these catalytic devices were sold annually in the 1980s. Recently, a motor company successfully applied Pd-perovskite catalysts to control automobile emissions.

Professor Misono received awards from the Chemical Society of Japan in 2001 and 1987, the Catalysis Society of Japan (CSJ) in 1994, and the Petroleum Institute of Japan in 1996 for these studies.

His research efforts in the last two decades have essentially followed the same direction with respect to Green Chemistry (GC). Environmentally friendly catalytic processes have long been the common concern of chemical engineers in Japan and in this area Japan made remarkable achievements in the 1970s and 1980s (Misono and Nojiri, Appl. Catal., 1990 and 1993). In 1990, he founded the Environmental Catalyst Forum in Japan and, with the help of colleagues, has organized international and national forums many times. He led the committee for environment and safety, CSJ, from 1999–2003. Based on these activities, he became one of the founders of the GC Forum, CSJ (1999) and the GSC Network (2000).

Conclusion

The roles for catalytic science and technology obviously continue to expand. The difficulty is that the catalytic performance characteristics now needed have become too tough to achieve by current catalytic science and technology. New catalytic technology is urgently needed. The design of catalysts at the atomic level, which can integrate multi-functions, is probably the goal. If enzymes were tolerant and active enough, they would be the ideal catalysts. However, this is not yet true and progress in synthetic catalysts is still rather slow. Therefore the new technology goals are still distant.

There are two possible approaches to overcome the current difficulties. One is a steady but very slow approach, which constructs catalyst building blocks step by step on a purely scientific basis. Another is the engineering approach, which establishes key technologies for catalyst design. For example, elucidation of the catalytic chemistry of noble metals supported on oxide in an oxidizing atmosphere is undoubtedly the key to the development of efficient environmental catalysts; little reliable information on this has been gained in the last decade.

As for GC, the top priority targets must be identified taking into account economy and contemporary technology, and the benefits of GC must be assessed in a transparent manner, that is visible to the community. Sound metrics which promote innovative R&D will help in this regard. GC sometimes promotes an image of chemistry that is ‘less negative’. It is very desirable, if not essential, to erase this image, for example, by ensuring that green chemistry is synonymous with innovative chemistry.

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