ter duo in ΝΑΕ. There have been three father-son duos over the years.

Pablo G. Debenedetti, Class of 1950 Professor in Engineering & Applied Sci­ence, department of chemical engineer­ing, Princeton University.

Jean M. J. Fréchet, professor, college of chemistry, University of California, Berkeley.

Ignacio Ε. Grossmann, Rudolph R. & Florence Dean Professor of Chemical Engineering, Carnegie Mellon Universi­ty, Pittsburgh.

Jack L. Koenig, professor of macro-molecular science and Donnell Institute Professor, Case Western Reserve Uni­versity, Cleveland.

William J. Koros, BF Goodrich Pro­fessor in Materials Engineering, depart­ment of chemical engineering, Universi­ty of Texas, Austin.

Octave Levenspiel, professor emeri­tus, department of chemical engineer­ing, Oregon State University, Corvallis.

Shirley E. Schwartz, retired senior staff research scientist, General Motors Research & Development Center, War­ren, Mich.

Hratch G. Semerjian, director, chem­ical science and technology laboratory, National Institute of Standards & Tech­nology, Gaithersburg, Md.

Daniel Shechtman, distinguished professor, department of materials engi­neering, Technion, Haifa, Israel.

C-P. (Ching-Ping) Wong, professor, materials science and engineering, Geor­gia Institute of Technology, Atlanta.

Janice Long

Former DuPont exec to take Praxair helm Dennis H. Reilley, 46, has been named president and chief executive officer of in­dustrial gases producer Praxair, effective March 15. He will succeed H. William lichtenberger, 64, as CEO and add the ti­tle of chairman on Lichtenberger's retire­ment in November. lichtenberger, who spent 33 years at Union Carbide, has led Praxair since Carbide spun it off in 1992.

Reilley most recently was an execu­tive vice president and one of two chief operating officers at DuPont. Until just two weeks ago, he had spent his entire 25-year professional career at DuPont. On Feb. 14, DuPont made company outsider Richard R. Goodmanson, 52, its sole COO and announced that Reil­ley was leaving to pursue other inter­

ests (C&EN, Feb. 21, page 5).

"Leaving DuPont was not a decision I took light­ly," Reilley says. "This represents an outstand­ing opportunity for me to work with and help lead a group of highly talented people in making Praxair even more successful. I look forward to meeting our future growth and earnings goals."

In 1999, Praxair had Reilley sales of $4.64 billion, down about 4% from 1998. However, net earnings increased about 4% to $441 mil­lion. The company's goal is "double-digit growth in earnings per share, improving return on capital, and maintaining a

healthy balance sheet," Lichtenberger said when reporting year-end earn­ings in late January.

"We believe our busi­ness and investment strat­egies strike the needed balance to meet these goals," he continued. "I am encouraged by the strong demand we are seeing in our major mar­kets, and that heightens my belief that 2000 will be a good year for Praxair."

Lichtenberger expects Reilley to continue the company's prog­ress in serving customers while improv­ing profitability and "to take it to the next level as we enter the 21st century."

Ann Thayer

EPA shuts web site, but finds no compromised files An inspection during a five-day shutdown of the Environmental Protection Agen­cy's World Wide Web site showed no ap­parent tampering with EPA's electronic files, according to the agency. In addition, sensitive commercial information, such as trade secrets, remains secure and has not been accessed by hackers, the agen­cy says.

EPA shut down its site on Feb. 17 be­cause of concerns about cyber security. This took place a day af­ter two members of the House of Representa­tives called on EPA to immediately discon­nect from the Internet and stay offline until the agency established adequate computer se­curity. Rep. Thomas Blileyjr. (R-Va.), chair­man of the House Com­merce Committee, and Rep. Fred Upton (R-Mich.), chair­man of the Commerce Subcommittee on Oversight & Investigation, asked EPA to act after General Accounting Of­fice investigators hacked into three of the agency's databases (C&EN, Feb. 14, page 62).

"We're talking not only about data worth hundreds of millions of dollars, but trade secrets and sensitive data that could put our national and economic se­curity at risk," Bliley says of his call for EPA to shut down its Internet site. The Virginia lawmaker has long been con­

cerned about computer security at the agency and accuses Administrator Car­ol M. Browner of "gross mismanage­ment of cyber security" during her sev­en-year tenure at EPA.

During the five days the site was down, computer security specialists checked the integrity of EPA's databases and built new electronic firewalls to keep hackers out, EPA spokeswoman Bonnie Piper explains. Databases were un­

harmed, and investiga­tors determined that no confidential busi­ness information in agency electronic files was accessed through the Internet, she says.

EPA issued a state­ment implying the public spotlight that lawmakers cast on the agency about its cyber

security problems drove it to disconnect from the In­

ternet. 'The decision to temporarily close access to the web site was made after... computer security experts warned that the public attention brought to the agen­cy's potential computer vulnerabilities made EPA a likely target for hackers," the agency said.

Jim Solyst, coleader of the Chemical Manufacturers Association's (CMA) in­formation management and right-to-know team, said on Feb. 17: "Under the circumstances, EPA has no other real alternative than to temporarily shut

FEBRUARY 28, 2000 C&EN 13

Our Mission-,

"«to protect human health and to

& £ I D A United States

news of the week down the sites. Apparently, the agency has some big holes in its computer se­curity system that must be plugged. The consequences of not doing so are potentially very high." Solyst reiterated CMA's concerns about growth in indus­trial espionage and the need for protect­ing confidential business information provided to EPA.

One activist group accuses Bliley of playing politics by calling attention to EPA's computer security as a way of lim­

iting public access to right-to-know data, which are available through the agency's web site. Jeremiah Baumann, environ­mental advocate for the U.S. Public Inter­est Research Group, says Bliley chose to target only EPA, but congressional inves­tigators have found cyber security prob­lems at 21 other agencies as well.

Bliley has rescheduled a hearing on EPA computer security for March 3. The hearing was initially slated for Feb. 16.

Cheryl Hogue

Racemic tack yields stereoregular polylactic acid Using racemic starting materials rather than single-isomer ones and employing a racemic catalyst, chemists at Michi­gan State University, East Lansing, have polymerized cyclic dimers of lactic acid to stereoregular polymer chains \J. Am. Chem. Soc, 122, 1552 (2000)]. Their achievement produces a crystalline polylactic acid resin with physical prop­erties that are superior to those of poly­mers with unordered configurations.

The result is one more step forward in efforts to develop "green" biodegrad­able plastics from renewable resources as alternatives to polymers derived from

petrochemicals. Potential uses for poly­lactic acid include cast, oriented, and blown films; fibers and nonwoven fab­rics; coatings for paper and cardboard; and thermoformed, injection-molded, or blow-molded containers.

The MSU publication comes hot on the heels of the introduction of commer­cial polylactic acid resin by Cargill Dow Polymers, Minnetonka, Minn. (C&EN, Jan. 17, page 13). Cargill Dow is a joint venture of Dow Chemical and Cargill, which is a producer and marketer of produce and processed food. The joint venture uses a biomass fermentation re-

Racemic catalyst stereoselectively polymerizes racemic monomer

o^cr^cHg D-Lactide

(-)-Catalyst

H 3 C Y°Y°

o^AcHa L-Lactide

(+)-Catalyst

CH3 O

(CH^CHO > ^ A ^ A ^ O — (-)- Cat

(CHgfeCHO

Cat =

CH3 O

(CH3)2CHO ̂ J<r, JL^O—(+)-Cat

O CH3

(CH3kCHO

action to produce L-lactic acid, which is then polymerized. The product resin is isotactic, meaning its repeating units all have the same configuration.

MSU associate chemistry professors Gregory L. Baker and Milton R. Smith III and graduate student Christopher P. Ra-dano report that the polylactic acid they prepare from a racemic mixture has a higher melting temperature than poly­mer prepared from a single enantiomer of the starting material. They use a mix­ture of D- and L-lactide cyclic dimers. The catalyst is a mix of (+)- and (-(-complexes of a chiral Schiff base with aluminum. The (+)-catalyst mediates polymerization of only the L-lactide in the mixture. The (-)-catalyst similarly polymerizes the D-lactide. Although the product resin is a mixture of all-D- and all-L-chains, the iso­tactic chains cocrystallize to form a ste-reocomplex that imparts a high degree of crystallinity to the material.

Last year, assistant professor Geoffrey W. Coates and graduate student Tina M. Ovitt in Cornell University's chemistry department, Ithaca, N.Y., reported the synthesis of a polylactic acid of enhanced physical properties whose repeating units have regularly alternating D- and re­configurations, an arrangement called syndiotactic [/. Am. Chem. Soc, 121 , 4072 (1999)]. The Cornell workers use a meso-lactide starting material, made from one D- and one L-lactic acid molecule. Their catalyst is the (-)-isomer of the cat­alyst used at MSU.

Coates says of the MSU research: "I think it is beautiful work. They've worked out a way to convert a racemic monomer using a racemic catalyst into a racemic, isotactic polymer. By controlling the rela­tive orientation of the methyl groups, a superior substance is formed. The strate­gy is reminiscent of Pinot's classic exper­iments to determine the nature of the ac­tive site of Ziegler and Natta's catalyst."

Coates also cites the role of polymer chemistry professor Nicolas Spassky of the University Pierre & Marie Curie, Par­is, who invented the chiral Schiff base cat­alyst that Coates and the MSU group use. Spassky made a chiral complex and found that, with a racemic monomer, the catalyst goes only after one monomer.

Baker and Smith are currently ap­plying polymerization via racemic cata­lysts to substituted lactides and are extending this general strategy to pre­pare high-valued crystalline materials from inexpensive racemic and prochiral monomers.

Stephen Stinson

1 4 FEBRUARY 28,2000 C&EN