Research Briefs from Toronto
Acid-base equilibrium calculations and BASIS computing language have been coupled in teaching introductory chemistry by two chemists from Carle ton University, Ottawa, Ont. Carle ton's Cooper H. Langford and Dr. Jay A. Young, on sabbatical from Kings College, WilkesBarre, Pa., told the chemical education divisions ( C I C / ACS) that coupling the two has the effect of "programing" acid-base calculations in a way that enhances clarity of the whole presentation. By using a computer, the chemists note, simplifying assumptions need not be used, and "messy and tedious" calculations can be handled with facility. A desired "feeling" for order of magnitude answers can be developed by basing the computer program for weak acid system calculations on iterative techniques. A poor first guess is noted by the computer, and the student is asked to try again. In this way students can approximate answers without doing any calculations. In addition, Dr. Langford and Dr. Young say, the discipline of a computer program seems to enforce the kind of precise analysis of a problem that is normally difficult to motivate. Students who have given the material serious attention reached an unusually high level of concrete achievement as measured on examinations, the Carleton chemists add.
The synthesis of artificial diamond and borazon presages a wide development of materials technology, Dr. Jack J. Bulloff, department of history and systematics of science, State University of New York at Albany, told the Division of the History of Chemistry ( A C S ) . Looking into the future of chemistry at high pressures and temperatures, Dr. Bulloff predicts room temperature superconductors, defect-free ultrastrength metals, novel electronically active materials for production and information systems, improved fuel elements for nuclear reactors, and special dielectrics. Magnetohydrodynamic and thermonuclear plasmas will be better understood, he adds. "In this region all equations of state tend to be reduced equations of state, and it might be possible to derive one or more universal equations of state about which a universal transfinite phase diagram might be based."
Fungus in stored wheat produces triglycerides that cause flour beetles to collect, says Dr. Alvin N. Starratt, Canada Agriculture Research Institute, London, Ont. Most active among synthesized model compounds are triolein and glyceryl-l,2-dioleate-3-palmi täte, says Dr. Starratt, speaking to the Division of Pesticide Chemistry (ACS) on work done with Dr. Sam R. Loschiavo, Canada Agriculture Research Institute, Winnipeg, Man. Triglycerides may be arrestants rather than attractants, Dr. Starratt theorizes. Beetles may stop when they encounter the compounds and begin feeding when stimulated by other compounds. Fungus and beetles may benefit one another, he thinks, with fungi producing chemical stimuli and beetles producing heat and water.
Halosugar nucleosides have been prepared by a direct onestep halogenation procedure developed by Dr. J. P. H. Verheyden and Dr. J. G. Moffatt at the Institute of Molecular Biology, Syntex Research, Palo Alto, Calif. Dr. Verheyden described to the Division of Carbohydrate Chemistry (ACS) a fast, efficient method for replacement by halogens of hydroxyl groups in the sugar moiety of nucleosides through reaction in D M F at room temperature with methyl triphenoxyphosphonium iodides or chlorides, or with the adducts derived in situ from triphenylphosphine and carbon tetrahalides (bromides or chlorides). High yields are obtained under mild conditions, Dr. Verheyden says. Both protected and unprotected nucleosides have been used. For example, 5'-deoxy-5'-halonucleoside derivatives have been prepared in high yield, and selective 5'-iodination of primary hydroxyl groups in unprotected nucleosides has also been achieved. Halonucleosides are very useful intermediates for synthesis of nucleoside analogs, which are potential antibiotic and antiviral agents, Dr. Verheyden points out.
Silicon rearrangements provide multiple pathways to making silicon compounds, says Dr. Robert West, University of Wisconsin, Madison, on the occasion of his receiving the Frederic Stanley Kipping Award in Organosilicon Chemistry. Dr. West describes his discovery, with Dr. H. Franklin Stewart and Robert Lowe, of a reverse Brook rearrangement. The Wisconsin men treat benzyloxytriethylsilane with butyllithium to get a-triethylsilylbenzyl alcohol. This is the reverse of the Brook rearrangement, which goes from alcohol to silyl ether in the presence of traces of sodium-potassium alloy or sodium hydroxide. Dr. West adds this reaction to 1,2-rearrangements of silylhydrazines and o-silylhydroxylamines as preparative methods in silicon chemistry. JUNE 1, 1970 C&EN 45
