PESTICIDES:
DDT substitutes Research workers at the University of Illinois, Urbana-Champaign, have culminated a five-year search for biodegradable replacement for DDT by applying for patents on seven new compounds, all DDT analogs. The discoverers say the new compounds are as effective as DDT against flies and mosquitoes, but their metabolites—unlike DDT's— do not accumulate in living tissues. Entomologist Robert L. Metcalf heads the UI team. Dr. Inder Kapoor, also an entomologist, and Dr. Asha Hirwe, a chemist, are his chief associates on the project, which has involved the synthesis and extensive testing of about 50 DDT analogs. Common to all the compounds is the replacement of DDT's p-chlorophenyl groups by other substituted phenyls to yield asymmetric molecules. Dr. Kapoor says that two of the analogs, l,l,l-trichloro-2-/?methoxyphenyl, 2-p-methylthiophenylethane and l,l,l-trichloro-2-/?-ethoxyphenyl, 2-p-methylphenylethane, are especially promising. The analogs are more selective than the broad-spectrum DDT, but tests have shown them to be as toxic to flies and mosquitoes as DDT itself. Furthermore, DDT-resistant strains of these insects appear to be susceptible to the analogs. Dr. Kapoor adds that the new compounds are distinctly less toxic to higher animals; for example, LD50 for mice is about 1000 mg. per kg., compared to 100 to 150 mg. per kg. for DDT. The compounds are "spray stable" and afford at least some of DDT's persistency, but they break down in living systems. Dr. Metcalf explains that they are converted by enzymes—mixed-function oxidases—to water-soluble metabolites that are rapidly excreted instead of being stored in fatty tissues (as are DDT's water-insoluble degradation products). The UI project has been funded by a grant from the Rockefeller Foundation. Patent rights will be assigned to the University of Illinois Foundation. According to Dr. Kapoor, "a few companies" are already negotiating for licenses to produce the new compounds. He notes that existing DDT plants should require only slight modifications to produce the asymmetric analogs, which are synthesized by a condensation process similar to that used to make DDT. Dr. Kapoor adds
Metcalf: effective but not persistent
that the United Nations' World Health Organization has already requested samples for testing. A recent WHO report warns that banning DDT before cheap and effective substitutes are found would be "a disaster to world health." ORGANOMETALLICS:
New synthetic method The first synthesis of organometallic derivatives of a majority of the transition metals, the lanthanides, and the actinides, and the first demonstration of a Grignard reagent in the gaseous phase were disclosed last week in Boston, Mass., at the 23rd International Congress of Pure and Applied Chemistry. Dr. Phillip S. Skell of Pennsylvania State University, University Park, told the delegates gathered in the towering Prudential Center that these findings were made possible by a unique new synthetic method that uses metals in the atomic state. The new route was developed in Dr. Skell's laboratory by Dr. L. Wescott, who found that metal atoms could be generated in a high vacuum by heat or an electric arc. These atoms can then be condensed with organic substrates at —196° C. to give the reaction products. This process, Dr. Skell says, produces metallic species that are highly reactive in ways not predictable by study of low-temperature forms. Platinum, for example, is normally considered to be very unreactive. However, he notes organoplatinum compounds form readily at —196° C. by cocondensation of the metal atoms with olefins. Organomagnesium compounds
can also be readily formed, but the specific reaction depends upon the electronic state of the magnesium atom. Ground-state (singlet) magnesium atoms generated by heat form a highly colored charge transfer complex with alkyl halides at —196° C; at higher temperatures they react to form Grignard reagents (alkyl magnesium halides) in the unsolvated state. Ground-state atoms form a similar complex with ammonia at —196° C; this complex decomposes to magnesium and ammonia at —78° C. The complex is a unique catalyst, effecting, for example, the stereospecific reduction of 2-butyne to irarcs-2-butene. Excited-state (triplet) magnesium atoms generated in an electric arc react with alkyl halides to form free radicals. The newly formed radical pair (R*— XMg·) does not couple, as would be predicted from room-temperature studies, but abstracts a second halogen atom from a neighboring alkyl halide molecule. Using the new technique, Dr. Skell's group has now made organometallic derivatives of more than 80% of the transition metals, lanthanides, and actinides. In these studies, he says, no major effort has been made to isolate pure organometallic compounds. Rather, the group sought to demonstrate the presence of such compounds by hydrolysis with deuterium oxide (to mark the metal-carbon bonds), and by observing catalytic isomerizations, hydrogénations, condensations, and polymerizations. Despite broad similarities of behavior within the various groups, Dr. Skell says, the behavior of each element is distinctly different from that of all others. Thus, he says, it is reasonable to anticipate a gradated and varied behavior for these organometallic compounds. COMPUTERS:
Chemists lag on use The first large-scale electronic computer was built 25 years ago; today, some 100,000 computers are in operation worldwide. And yet, says Dr. Peter G. Lykos of the National Science Foundation's office of computing activities, most chemists are still not "reasonably aware" how important the computer has become to chemistry. To help "spread the word," a conference on computers in chemical education and research was held last week at Northern Illinois UniAUG. 2, 1971 C&EN 7
Chemical worm This week versity, De Kalb, 111. The conference was cosponsored by NSF and the ACS Division of Chemical Education and codirected by Dr. Lykos, Dr. F. M. Miller, and Dr. W. Roy Mason, the latter two of NIU's chemistry department. More than 200 chemists, computer scientists, and educators exchanged views on how best to use computers—not just as "number crunchers" but as tools that can improve the quality of data, free the experimenter from routine tasks of equipment manipulation, and, paradoxically, often give more "personal attention" to a student than can a busy human instructor. In a session on computer control of experiments, Dr. Paul W. Gilles of the University of Kansas commented on his group's use of a minicomputer for high-temperature mass spectroscopy experiments: "We look upon a computer as just another piece of apparatus. But with it, we can do experiments we can't do without it; we can perform our experiments more efficiently; and we can utilize the data in a much more effective way than we could in the past." Speaking on the computer's role in undergraduate curriculum development, Dr. Joseph R. Denk of the North Carolina Educational Computing Service took note of the "strange spectrum" of activity in the field: some large universities "loaded with computer power" don't have a single undergraduate chemistry course that involves the computer; yet, some small colleges with a single teletype terminal have chemistry curriculums for which the computer is essential. Dr. Denk contends that the problem is not a lag in technology or systems but a lag in educational philosophy, and that the publishor-perish system is a primary cause. Computer curriculum development will not flourish, he believes, so long as the work "is not adequately rewarded in the academic market." SCIENCE R&D:
Spur growth, aid trade A revamping of the nation's antitrust laws and new federal incentives for technological development may be necessary to remedy the nation's slackening trade balance, Commerce Secretary Maurice Stans said last week. The nation's trade surplus may disappear alto8 C&EN AUG. 2, 1971
gether this year for the first time since 1893, he warned, adding that the conditions which have led to this situation are "clearly serious and growing worse." Secretary Stans was lead-off witness at three days of hearings last week on "Science, Technology, and the Economy" before the House Subcommittee on Science, Research and Development. Rep. John W. Davis (D.-Ga.), subcommittee chairman, says the subcommittee hopes to determine what resources the nation should invest in R&D both in the public and private sectors and the best ways for making these investments. The subcommittee plans a detailed study of the relationships among science, technology, and the economy. It will hold additional hearings later this year. Some of the factors underlying the decline in U.S. technological strength, according to Secretary Stans, are an accelerated worldwide transfer of technology, growth of foreign government incentives, and the increasing cost and risks of major technology breakthroughs. Of all the factors that influence the U.S. international trade position, such as tariffs, quotas, and nontariff barriers, the major element which the nation can influence decisively for the long run, he said, is the level of technological development. To enhance and spur the nation's technological development, the Secretary offered the subcommittee "program options," which he said ought to be looked at carefully. One program option would centralize federal activities for enhancing, assessing, and forecasting industrial technology. Another option calls for modernization of U.S. antitrust laws to permit pooling of funds and risks associated with major technological advances. Direct and indirect financial incentives aimed at stimulating the development and use of new technology might also be created, Secretary Stans told the subcommittee. For example, direct federal assistance might be provided through loan guarantees, cost sharing, grants, and procurement incentives. Indirect financial assistance could include tax incentives for R&D and capital expenditures, or possibly matching tax incentives such as depreciation allowances, investment credits, credits for incremental R&D, and favorable treatment by U.S. competitors for inventors.
I UNEMPLOYMENT:
ICI to lay off workers The U.K.'s Imperial Chemical Industries plans to reduce the number of employees in its fibers division by 1450, or 8% of the division's total work force. Problems of rapidly rising costs, slack demand, and pressure on nylon prices were leading to heavy losses, leaving the company with little choice, according to ICI Fibres deputy chairman Kenneth Gardener. The layoffs represent about 1% of the company's 142,000 U.K. employees. Unemployment in the U.K. chemical industry is, in general, low, according to Department of Employment and Productivity figures. About 11,000 (2.4%) are registered as unemployed out of a total industry work force of some 450,000. The U.K.'s overall unemployment rate is about 3.3%. ICI Fibres, which supplies more than 50% of U.K. nylon fibers demand and about 70% of polyester demand (and whose 1970 sales were more than $300 million), is confident of a recovery from the current slump in the fibers and textile industry this fall, which is nevertheless when the first of the 1450 employees are scheduled to be terminated. Expected growth in the nylon business, for which ICI recruited strongly about 18 months ago, hasn't materialized, and the company apparently now has too many employees in its nylon fibers operations. ICI's present problems stem in part from inroads polyester is making into markets previously held by nylon. U.K. annual demand for nylon fibers is about the same as last year's 285 million pounds, Mr. Gardener estimates. Meanwhile, demand for polyester is growing rapidly, last year topping 160 million pounds. U.K. and other West European producers may even switch the current nylon overcapacity to polyester in an effort to keep up with market trends, Mr. Gardener says. Another part of the problem is that slack demand and the economic squeeze have left little room for the price increases ICI needs to make its nylon business profitable. The company last February hiked nylon prices by 7.5%, but some of the increases didn't stick, Mr. Gardener says. Costs are meanwhile growing 10% a year.
