N18

Haldor Topsoe, Ammonia Synthesis and Beyond

The accounts by Burt Davis on “Early Work on Ammonia Synthesis in the U.S.”

in Newsbrief Section have already pro- vided several fascinating glimpses into the early history of catalysis and into the lives of great masters such as Paul Emmett and

Hugh Taylor. In Applied Cata/ysis of 4 January 1994,

the Newsbrief focused attention on a still living legend, Haldor Topsoe, who was 80 years old in May 1993. Starting as one man’s “crazy idea” and with the help of just one chemist (Dr. Anders Nielsen) in the Nazi-occupied Denmark in the 1940’s, Hal- dbrTopsoe built up a technological empire (or is it a republic?) of which all we catalytic

chemists and chemical engineers could be proud for the last 35 years. Researchers from the Topsoe Laboratory tell us that Haldor Topsoe, now over eighty, still walks routinely into the laboratories, talks with everyone he meets there, and continues to be a source of inspiration to the young and not-so-young there.

To honour such a great pioneering leader of catalysis R&D in his 89th year and to commemorate 50 years in catalytic re- search by his first colleague, Anders Niel- sen, a small international get-together and

symposium were arranged at Hornback, denmark from 1st to 4th September 1993. Michael Boudan has often said that re- search on the ammonia synthesis catalyst is a good indicator of the overall state of the art in catalysis R&D and of our under- standing of catalytic phenomena. To ac- knowledge this fact and pay tribute to the outstanding personal contributions of An- ders Nlelaen to research on ammonia syn- thesis, the Hornback Symposium rightly

a)pplled catalysis A: General

had the title: Frontiers in Catalysis: Am- monia Synthesis and Beyond. The 17 papers presented there have been bundled into the October 1994 issue of the new journal, Topics in Cata/ysis. This issue opens with two very personal and thought- provoking memoirs: “Science, develop- ment - and global issues” by Haldor Top- soe; and “Personal perspectives from fii

years in catalysis research” by Anders Nielsen.

P.G. MENON

Methane to Ethylene with 85 Percent Yield

A great improvement in CB selectivity and yield in the oxidative coupling of meth- ane (OCM) have been reported by C.G.Vayenas with co-workers in Science,

284 (1994) 1583. By using a gas recycle electrocatalytic reactor with Ag-based catalyst combined with a molecular sieve trap in the recycle loop, they have obtained a yield of Cp hydrocarbons up to 88% and, what is even more interesting and import- ant, an ethylene yield up to 85%. The se- lectivity to ethylene was up to 88% for a methane conversion of up to 97%. When oxygen was introduced to the gas phase instead of electrochemically, the results were practically the same as those above. The improvement in the selectivity and yield were attributed to the molecular sieve, which removes the Cp hydrocarbons from unreacted methane and traps ethylene more effectively than ethane. This work shows that reactor design and improved separation of products are the areas where

Volume 121 No. 2 - 19 January 1995