Monsanto buys Grace's ag biotech operation Monsanto will buy the plant biotechnology assets of W.R. Grace's Agracetus subsidiary in another move to strengthen its agricultural biotechnology efforts. For $150 million in cash, Monsanto will get the Middleton, Wis.-based subsidiary's transgenic plant business and facility, as well as related intellectual property. About 65 Agracetus employees will move to Monsanto. Agracetus1 strength is its gene insertion technology, which can be used to alter the genetic makeup of plants and to insert genes in cells to produce proteins for drug and industrial applications. The technology has helped create transgenic versions of cotton, soybeans, beans, and other crops. Based on this technology, in 1992 Agracetus received a broad and controversial U.S. patent that covers all forms of transgenic cotton. The company also has applied for broad patents in the U.S. and abroad on soybeans. Since 1991, Monsanto has been a licensee of Agracetus' technology, most notably under the cotton patent that enables Monsanto to market its versions of transgenic cotton. However, Monsanto was among a group of companies and other organizations that opposed Agracetus' soybean patent filing in Europe in 1994. And the two companies have disputed technology rights for virus protection in potatoes. At least for Monsanto, these issues will be resolved when it secures Agracetus' intellectual property. Agracetus has been a wholly owned subsidiary of Grace since 1990. From 1984 through 1989, Grace operated the business as a joint venture with California-based Cetus. Before that, the business was a part of Cetus, which also had programs in drug development. Monsanto's own decades-long agricultural biotechnology effort is coming to fruition with recent U.S. regulatory approval for insect-resistant cotton and potatoes and for herbicide-resistant soybeans and cotton. In the past few months, it has set up R&D alliances and taken equity stakes in two small agricultural biotechnology firms—Calgene of Davis, Calif., and Ecogen of Langhorne, Pa. Monsanto created a business unit, Ceregen, in March 1995 to focus on developing new agricultural products. Grace has been selling noncore busi-
nesses, including health care and water treatment, to focus on its specialty chemical and packaging businesses. Agracetus has been one of several businesses within Grace's commercial development group that, in past years, conducted discovery research with the objective of developing new businesses for the company. Grace will keep Agracetus' human gene therapy business, which includes about 35 employees, and operate it as In this micrograph of a Pt/Rh catalyst, Auragen Pharmaceuticals. Ann Thayer the brighter atoms are rhodium.
European scientists image bimetallic catalyst European scientists have imaged a platinum/rhodium alloy surface with atomic resolution and identified the chemical nature of the surface atoms. This may open the way to new techniques for analyzing catalytic surfaces and designing better industrial catalysts. The research was done by Bernhard E. Nieuwenhuys and Peter T. Wouda of Leiden University's Gorlaeus Laboratories in the Netherlands and by Michael Schmid and Peter Varga of the Institute for General Physics of the Technical University of Vienna. Their work, combining scanning tunneling microscopy (STM) and atomic emission spectroscopy (AES), will be published soon in Surface Science. The surface composition and structure of bimetallic alloys strongly affect the catalytic activity of the surface. Ensembles or isolated atoms of either component may be important, depending on the use. STM has been used for many years to study metal surfaces, but mostly to confirm what was already known of atomic symmetry and structure. This work from Leiden and Vienna appears to go much further by permitting quantitative measurements directly from the images. "This discovery could open a new avenue for the surface science of alloy catalysts," comments Wolfgang M. H. Sachtler, a chemistry professor at Northwestern University in Evanston, 111. "Once it is possible to distinguish the atoms of each element at the surface of a bimetallic catalyst, the way is open to identify the ensembles of the atoms that are most efficient for an application and steer catalyst preparation to optimize for these." Platinum/rhodium alloys are used in the production of nitric acid and hydro-
gen cyanide, but their most important application is probably as the catalyst for three-way auto exhaust converters. The catalyst for this use is designed to simultaneously oxidize residual carbon monoxide and hydrocarbons and to selectively reduce nitric oxide to molecular nitrogen. These catalysts exhibit variable surface compositions because of alloy segregation induced by chemical and thermal history. Understanding the segregation behavior would aid in designing better catalysts. The research group set out to obtain chemical resolution on the (100) surface of a 50/50 platinum/rhodium alloy single crystal by STM. The main difficulties were the similarity in atomic radii of the two metals and their complex electronic structure. The surface structure and distribution of the two metallic elements were obtained with the aid of statistical analysis and comparison with AES results, thus identifying the chemical nature of the elements. AES revealed significant platinum surface segregation. The research group concludes that the platinum enrichment in the top layer of the surface is accompanied by depletion in the second layer. Also, clearly visible in the STM images is a small amount of a third component on the surface. The group presumes this to be carbon originating either from residual hydrocarbons in the STM chamber or from carbon segregation in deeper layers of the crystal. During the investigation, the group was able to image edges of a large terrace on the surface. The edges seem to be almost entirely populated by platinum atoms. This finding agrees with independent calculations, which predicted that about 82% of all edge atoms would be platinum. A limited amount of clustering is also evident, but the clusters seem to be very small. Joseph Haggin APRIL 15,1996 C&EN
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