The Chemical World This Week RESEARCH & TECHNOLOGY
JULY
2,
1962
CONCENTRATES
• N e w d a t a on s t e r e o s p e c i f i c polymerization mechanisms w e r e prominent at the first biennial Polymer Symposium, held at Michigan State University and sponsored by the ACS Division of Polymer Chemistry. T h e transition m e t a l halide p a r t of a Ziegler catalyst may play a major role in determining stereospecificity in the polymerization of olefins, Dr. John Boor, Jr., of Shell Development Co., CataEmeryville, Calif., told the symposium. lysts studied were diethylzinc, ethylzinc chloride, and diethylcadmium, in combination with different titanium chlorides. Dr. Boor says his findings indicate that isolated sites with different capacities to complex electron donors exist on the crystal surface of the titanium chloride. Thus, initial addition of an amine to these catalysts sharply drops catalytic activity b u t drastically increases specificity. This means the amine has inactivated the nonstereospecific sites of the catalyst complex, he says. Additional amine, however, boosts catalytic activity with hardly any increase in specificity. This activating effect may stem from the adsorption of amine molecules near an active and stereospecific site, Dr. Boor theorizes. Catalysts that polymerize alkyl vinyl ethers to crystalline, high molecular weight polymers are based on metal alkyls a n d metal alkoxides combined with various acidic agents, and probably proceed by a cationic insertion mechanism, Dr. E. J. V a n d e n b e r g of Hercules Powder says. One group of catalysts consists of the reaction products of these compounds with sulfuric acid used either alone or with alkyl or alkoxide activators. Another group is m a d e u p of various metal sulfates combined with these compounds. Dr. Vand e n b e r g proposes that the unusual factor in the catalyst system may b e the presence in the counter ion of transition metals or aluminum disposed geometrically to provide a n u m b e r of coordination sites. Such sites can coordinate with the ether oxygen of the growing cation—which lie believes is more likely a vinyl ether carbonium ion than oxonium ion—to provide a tighter, more hindered ion pair. H e further believes that coordination of a vinyl ether monomer would be through its ether oxygen, not through the double bond, which is the theory proposed for polymerizing olefins with transition metal catalysts. Polymers m a d e from these catalysts have better mechanical properties and solvent resistance than do other stereoregular vinyl ether polymers, Dr. V a n d e n b e r g says.
• Two types of neutrinos exist. Columbia University and Brookhaven National Laboratory workers say [Phys. Rev. Letters, 9, 36 ( 1 9 6 2 ) ] . O n e type is connected with mu-mesons ( m u o n s ) and the other with electrons. Working at Brookhaven's new 33-b.e.v. alternating gradient synchrotron, the scientists allowed 100 trillion neutrinos p r o d u c e d from pi-mesons to pass through a 10-ton spark chamber. Fifty of the neutrinos interacted in the chamber, making energetic events. Of these, 29 showed only a single energetic muon being produced, while the rest showed muons being p r o d u c e d along with other particles. In no case was a single energetic electron produced. It shows that neutrinos arising from the decay of the pi-mesons are different from those involved in beta decay. • A digital c o m p u t e r - d i r e c t e d s y s t e m t o control c o m p l e t e l y the making of s t e e l (from order specifications to ingot) is scheduled to start u p late this year at the Roemer Works of Sharon Steel Corp., Farrell, Pa. Supplied by Minneapolis-Honeywell Regulator Co., the Honeywell 290 process computer will directly control two oxygen furnaces simultaneously. T h e new plant, designed and built by D r a v o Corp., has an initial rated annual capacity of 1 million ingot tons and will use the Swedish-developed Stora-Kaldo oxygen process, for which Dravo is the U.S. licensee. T h e computer, supplied with product and input spécifications, will directly control the charge of hot metal, scrap, and flux materials to the furnaces. D u r i n g the blow it will calculate and control the speed of rotation of the furnaces, the amount of additives supplied, and injection of oxygen into the furnaces. T h e Stora-Kaldo process converts most of the carbon monoxide to carbon dioxide, thereby increasing thermal efficiency. Thus, about 1.6 tons of steel are prod u c e d per ton of hot metal charged when scrap is used as a coolant. • The California Motor Vehicle Pollution Control Board approved two more applications for crankcase ventilating systems. Ford Motor Co. and United Air Cleaner Division of Novo Corp., Chicago, were granted certificates of approval. Ford, the first major automobile manufacturer to win approval for a crankcase system, will make the unit a standard item on all of its 1963 model six-cylinder cars. This brings to seven the n u m b e r of crankcase devices now approved by California's MVPCB. JULY
2,
1962
C&EN
35
