THE CHEMICAL WORLD THIS WEEK 0.2 M sodium, chloride solution of D N A a degree as to prevent the polymer trom the acidic form at one p H unit lower than from neutral to 2.6 b y dialysis, it w a s ob- being more than a wax. without PVP. Because of the high affinPolyvinyl Pyrrolidone. H. P. Frank, ity for PVP, substantive dyes can b e served that there was no molecular weight stripped from cotton b y that compound. change, but t h e molecule collapsed into formerly of the University of Vienna and A group of three papers, by A. Rousset, a rod, as indicated by angular intensity now of Brooklyn Poly, presented a paper for G. Oster, of t h e latter institution, dealBordeaux; P. Putzeys, Louvain; and A. distribution, with a length of 3000 A. and J. Oth a n d V. Desreux, Liege, disThe effect of sodium chloride in the ing with spectral studies of polyvinyl cussed techniques of calibration of light solution was observed to b e less than pyrrolidone. A considerable shift in t h e scattering and emphasized the importance expected for a linear coil, reported Dr. ultraviolet absorption peaks w a s noted of uniformity. Other groups of papers Doty; the change in viscosity in going below pH 1 to 2 and above pH 11 to 12. dealt w i t h x-rays, ultraviolet, and a variety ' from 0.2 M sodium chloride to zero fits Molecular binding of iodine w a s indiof optical subjects. Among the speakers better the idea of a molecule with small cated to be strong, beginning w i t h difficulty but proceeding with increasing ease were J.vG. Kirkwood, Yale; H. B. Klevens, branches. to the extent of o n e molecule per monomer. University of Minnesota; and W. Heller, pH Effects. Charles Sadron, Strasbourg, Wayne University. T h e spectra of several anionic dyes presented findings o n the shape of the T h e group is making plans to hold a thymonucleic acid molecule, using sodium were shown by Oster to be altered b y colloquium next year in Uppsala, immedichloride solutions at p H 7 and pH 3.8. PVP and similar results were found with ately after t h e July meeting of the InterFlow birefringence, viscosity as a func- some dyes substantive to cotton. W i t h national U n i o n of Pure and Applied Chemtion pf velocity gradient, and light scat- benzopurpurine, the addition of 0 . 0 1 % istry in Stockholm. tering were observed with consistent evi- PVP produced a shift from the basic to dence of a distinctly differing form of the molecule under different conditions. C&EN REPORTS: Air Pollution and Smoke Prevention Association of America In comparing flow double refraction related to viscosity of solvent there was observed a strong and distinctive similarity b e t w e e n the acid solution of nucleic acid and a chain polymer, such as polystyrene, in solution; in neutral solution, reported Prof. Sadron, the nucleic acid behaved »much more like a rigid rod-shaped molec u l e such as tobacco mosaic virus. It was Styrene and halogen wastes at Dow's Midland concluded that in neutral solution the plant combined to form e y e irritants thymonucleic acid molecule is pseudorigid, while in acid solution it is deformable into various possible shapes; the C L E V E L A N D . — That industry and the or six years for abatement facilities and structure as a function of pH was said to public are becoming more interested in spends from $ 5 0 0 0 to $10,000 a year in b e irreversible. The speaker offered some air pollution abatement is evidenced by operating d i e m . Efforts h a v e been divery general assumptions about the origin the fact that industry is spending approxirected toward replacing old, hard-to-conmately $120 million each year for polluof this change of structure. trol systems b y modern, well instrumented, Silicones. Structure studies of silicones tion control equipment in the U . S. Add uniformly controlled systems; installing were reported by Herman Mark, Poly- to this the 600 industry and government auxiliary scrubbers or absorbers to pick technic Institute of Brooklyn. Knowing engineers who came here for the 45th up unavoidable losses; installing independently powered, standby equipment to that silicones tend t o cyclize at relatively annual meeting of the Air Pollution and carry on in case of a general power faillow molecular weights, it w a s hypothe- Smoke Prevention Association of America ure or other process stoppages in critical sized that in higher molecular weights from June 9 to 12. T h e chemical industry, according to locations; eliminating coal as the primary there might b e chains of interlocked rings. source of heat and power; and extensive This was supported b y the facts that H. C. Hosford of D u Pont, occupies an and ever-continuing training of operators. gelation occurs w h e n high polymerization unenviable position in the air pollution Elimination of Hydrofluoric Acid Vais attempted through elimination of water picture, because the average lay person pors. W h e n Pennsylvania Salt Mfg. Co. from bifunctional monomers and that the regards all chemicals as deadly poisons. first entered the field of hydrofluoric acid higher molecular weight silicones cannot H e knows something about smoke and manufacture, one of t h e principal probbe washed out of t h e product of styrene dirt but there is some mystery about what lems in connection with plant operation and divinyl benzene polymerized in their comes out of a chemical plant. However, was economical control and elimination of presence; low molecular weights can be Mr. Hosford remarked, the chemical industry is no more offensive to its neighthe acid vapors. T h e stack from the washed out. Treatment of silicones with ethylene bors than any other heavy industry, since> process contains a small concentration of diisocyanate yielded a product much more the problems of air pollution are nuisancei hydrofluoric and other acids and, ovei the years, Pennsalt tried many methods like a normal polymer in its character- problems, not health problems. T h e sincerity of industry's endeavor to> of eliminating or controlling them. One istics, reported Dr. Mark. T h e conclusion of the most obvious solutions was the use was that the straight chain silicones, with reduce air contamination, said Mr. Hoshydroxyl end groups, were seized by the ford, is demonstrated in the amount oft of packed t o w e r s in which the vapors isocyanate to form compounds while the money being spent for abatement andI were water scrubbed and the effluent liquid neutralized and sent to a waste cyclized silicones were not and could be control facilities and it is rare that a monetary return is received on such investlagoon. However, the bulkiness and exwashed from the mixture. As the degree ment. D u Pont, he said, has a capital1 pense of this installation, plus other disof polymerization of silicones was about investment of over $ 5 million in polluadvantages, such as mist carryover and 30, it was concluded that the small diisotion abatement facilities and has author- corrosive action of the acid, ruled out cyanate did not constitute a large enough ized $1.5 million for facilities not yett this solution. proportion of the molecule to produce the installed. According to C. R. Brown and R. W. c h a n g e in nature. The change was preAt the Cleveland works, 'where Mr. Tomlinson o f Pennsalt, the controlling s u m e d to h a v e been produced by the Hosford serves as assistant, technical sufactor in t h e absorption of these objecremoval of t h e cyclic silicone materials perintendent, D u Pont has spent an av- tionable vapors was their low concentrawhich were acting as plasticizers to such erage of $30,000 a year for the past five tion and extreme solubility. In this case
Industry Spending $120 Million Each Year o n Smoke Prevention
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THE CHEMICAL WORLD THIS WEEK the concentration of acid vapor was too low to provide good mass transfer with the limited quantities of water that can be put through a reasonably sized tower, These characteristics indicated that an ejector, which can handle large quantities of water and also act as an exhauster, should be able to eliminate entirely the small acid content of the waste gases. Other factors, the authors pointed out, influencing selections of ejectors include the advantage of gas film break up due to the turbulent action and the absence of any mechanical or moving parts subject to mechanical failure. Another aspect is that application of water-powered ejecters assures an adequate supply of water to scrub the vapors efficiently. Corrosion, however, offered problems here and the first ejector used did not stand up under the corrosive action of hydrofluoric acid. Consequently Pennsalt designed an ejector from A split F, a modified phenolic resin fortified with an inert carbon filler. Ejectors lined with Kel-F have also been used with success. Eye Irritants. In August 1940, the complaint terminology at Dow's plant in Midland suddenly changed from "stink" to "tear gas." Employees had become accustomed to other well known lachrymators, such as chlorine and bromine. By the summer of 1941 it was proved that two effluents were combining to produce a lachrymator of outstanding potency, said E. M. Adams of Dow. T h e waste water settling pond near the electrolytic cells producing magnesium was found to be the worst spot and a check showed that waste water from the ethyleneproducts plant which carried an odor associated with styrene was emptying into the pond from a nearby sewer. Chlorine wastes from the electrolytic cells were reacting with the styrene to contaminate the magnesium plant environment for a distance of 2000 feet or more. Corrective measures were centered around elimination of styrene as the quickest solution. These measures controlled the formation of the eye irritant satisfactorily. However, during wartime expansion in 1943 another plant and pond came into unfortunate association and when the wind came from the southeast, the e y e irritant started forming again. This time, however, southeast winds were infrequent and no specific measures were taken. In 1948, the popularity of the "home wave" led D o w into the manufacture of bromates and again the eye irritant began to form, this time from bromine wastes. After the third occurrence, Dow employees began to notice the association between occurrence of the lachrymator and sunlight. Laboratory experiments confirmed the suspicion that sunlight acted as a catalyst for the reaction between styrene and a halogen. After the third occurrence, D o w had to stop operation of bromine cells w h e n the wind was in the right quarter and finally redesign the bromate cells with a provision for scrubbing the bromine from t h e exhausted air. V O L U M E
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Alan S. Michaels (right) of the MIT Soil Stabilization Laboratory discusses the trie effects o £ silicones and other additives on the water-retaining properties of kaolinic soils. Listening are T. William Lambe (left), director of the Soil Stabilization Laboratory, and Thomas K. Sherwood, dean of engineering at MIT C&EN REPORTS: Conference on Soil Stabilization
Engineering Potentials of Soil Conditioners Demand Emphasis Economics cannot be analyzed in terms of cost per pound of chemical additive CAMBRIDGE, MASS.- The dramatic success achieved in recent months through the use ol soil conditioners in agricultural applications has highlighted the need tor t h e thorough investigation of these same materials i n the field of engineering. Because today relatively little is known of t h e effects o f these chemicals on the engineering properties of soils; much experimental work needs to be done, both in t h e laboratory and in the field. "However," said Alan S. Michaels of MIT's Soil Stabilization Laboratory, "it is important to maintain proper perspective in attempting t o predict what developments may result from further studies of the use of these chemicals for changing soil properties. To envision, for example, the conversion of sand or m u d into a concretelike structure b y the addition of a fraction of a per c e n t of a chemical additive is wishful thinking—at least on the basis of our present knowledge. On the other hand, many soil problems ascribable to soil permeability characteristics, water sensitivity, and other factors appear to b e amenable to treatment b y trace chemicals." These views were expressed b y Dr. Michaels at the Conference on Soil Stabilization presented at Massachusetts Institute of Technology, June 18 to 20. T h e conference, attended by over 3 5 0 scientists JUNE
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and engineers, featured 26 papers and 11 prepared discussions by leaders in the field of soil stabilization. The conference covered mechanical, chemical, and electrical methods of stabilization, as well as their numerous applications. As one speaker defined it, soil stabilization, in its broadest sense, means the control or alteration of soil properties—particularly such properties as strength, permeability, and compressibility. Although engineers at present may discount the use of chemical stabilizers in engineering applications, mainly because of cost, such thinking may be misleading. "There are indications," said T. William Lambe, director of the MIT Soil Stabilization Laboratory, "that some of these chemicals may be effective in quantities as low as 0.02% of the dry soil v> jight. A very expensive chemical used in a 0.02% dosage can be far cheaper in the long run than a low-cost chemical used in 5% dosages. Therefore, quite obviously, the economics of soil stabilization cannot simply be analyzed in terms of the cost per pound of additive." Today, vastly more research in the field of soil stabilization is necessary, Dr. Lambe emphasized. A great need exists for a fuller understanding of the basic nature of soil itself. How can soil be best waterproofed unless the nature of soil water is 2705
