I PERKIN MEDAL |
Edith M. Flanigen Wins Perkin Medal dith M. Hanigen, senior research fellow at UOP's technical center in Tarrytown, N.Y., has been awarded the 1992 Perkin Medal for her outstanding achievements in applied chemistry. She is the first woman to receive the prize in its 86-year history. The medal especially recognizes her syntheses of aluminophosphate and silicoaluminophosphate molecular sieves as new classes of materials. These microporous, crystalline, macromolecular substances are cousins of synthetic zeolites, which have become widely used as shape-selective catalysts and sorbents. Thus, Hanigen's 200-odd aluminophosphates and silicoaluminophosphates, divided into two dozen different structures, seem likely to become as important in their commercial successes as they have been landmarks of fundamental inorganic chemistry. Flanigen has also made contributions to the field of synthetic zeolites. The American Section of the Society of Chemical Industry awards the Perkin Medal annually to an outstanding chemist chosen by officers of the Society of Chemical Industry, American Chemical Society, Electrochemical Society, the American Section of the Société de Chimie Industrielle, American Institute of Chemical Engineers, and American Institute of Chemists. Flanigen was born in 1929 in Buffalo, N.Y. She received a bachelor's degree in chemistry from D'Youville College in Buffalo in 1950 and a master's degree from Syracuse University in 1952. In 1983, D'Youville awarded her an honorary doctorate in recognition of her many accomplishments. In 1952 Hanigen joined Union Carbide and stayed with the company's Linde Division until 1988. In that year, Union Carbide assigned Linde's molecular sieve and catalyst business to the UOP subsidiary of Allied-Signal as a part of making UOP a joint venture of Union Carbide and Allied-Signal. Flanigen's earliest contributions to the field of chemistry were new methods to make synthetic zeolites. Zeolites
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the different solubilities of alumi num, silicon, beryllium, and chro mium oxides in aqueous gels. Linde found a market for these products as synthetic gemstones. Hanigen also developed an acid extraction process to convert the small-pore zeolite mordenite into a large-pore variant. The large-pore form provided greater catalytic ac tivity for converting normal into branched-chain hydrocarbons. Working with chemistry professor Herman A. Szymanski of Canisius College, Buffalo, Flanigen applied transmission and reflectance infrared spectroscopy to process control and characterization of zeolites. Together, they found a fingerprint region be tween 200 and 1400 cm"1 that yield ed information about pore sizes, structural elements, and acidity. Flanigen again used template methods to make aluminophos are metal aluminosilicates of the gener- phates and silicoaluminophosphates. al formula M 2/ „ · A1203 · xSi0 2 · J/H20, For these she employed a wide variety where M is an alkali or alkaline earth of amines as well as tetraalkylammoni metal and η is its oxidation number. um salts as templates. She heated aque Though zeolites are found in nature, ous gels to between 100 and 250 °C, Hanigen and others have found ways to with the temperature a factor in con make naturally and non-naturally occur trolling the structure. Other structurering structures by heating aqueous alu controlling variables were template type and concentration, gel oxide com mina-silica gels at 100 °C to 450 °C. For example, chemist Donald Breck of position, heating time, and pH. In addition to using aluminum, phos Linde had made small amounts of a new type of zeolite called zeolite Y that phorus, and silicon as structural ele showed promise as a fluid cracking cat ments, she succeeded in incorporating alyst in oil refining. Hanigen succeeded transition metals such as cobalt, iron, in the difficult task of making large magnesium, manganese, and zinc into the framework. To date, substitution by amounts of zeolite Y reproducibly. Also, chemist Robert M. Milton of a total of 13 different transition metals is Linde had used metal ions as templates possible, using as many as six at a time. around which aluminosilicates could Thus the number of structures and sur form in different structures. Flanigen face environments is almost limitless. Besides being fundamentally impor extended this templating technique to the use of tetraalkylammonium salts to tant as new materials, the phosphatebased microporous crystals are less form yet newer structures. In the early 1960s, the Massachusetts acidic than zeolites. This may make Institute of Technology's Lincoln Labo them more useful as cracking catalysts ratory commissioned Linde to make as evidenced by their smooth perfor synthetic emeralds for masers, which mance in butane cracking experiments. were the microwave forerunners of la UOP spokesmen say the company will sers. Flanigen devised a nonequilibri- soon introduce several of these materi um process to make emeralds by using als commercially. Stephen Stinson temperature and pressure to control MARCH 9, 1992 C&EN
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