THE CHEMICAL WORLD TH!S WEEK carried out on solutions of cellulose in cupiiethylene diamine, using a PVB m e m brane which had been left in the leach ing bath for four minutes. Using sulfite pulp, a degree of polymerization ( D P ) of 450, calculated from the reduced os motic pressure, agreed favorably with the value of 468 obtained from intrinsic vis cosity. Similar agreement was obtained using rayon samples. The Kel-F films were prepared by spray coating a stainless steel or chrome plate with a dispersion o f the polymer in xylene. Dr. Mark explained the advantages of the Kel-F membranes were that they were completely insoluble in the solvents gen erally used for osmotic pressure measure ments of high polymers, and they are in ert towards oxidation. The Brooklyn Poly technic group has carried out measure ments not only on solutions of cellulose in cupriethylene diamine, but also on a solu tion of polystyrene in benzene to show the applicability of the membrane to a piirely organic system. In Great Britain, polyvinyl alcohol films, prepared by controlled evaporation of a dilute aqueous solution of the polymer, have been used as semipermeable m e m branes in nonaqueous systems. H. T. Hookway and R. Townsend, of he D e partment of Scientific and Industrial Re search, reported o n this development. The speed and semipermeability of these membranes may be controlled by exposure for five days to atmospheres oi different relative humidities, explained Dr. Hookway. The higher the relative hu midity, the less permeable is the m e m brane. Polydiallyl phthalate and phenol-form aldehyde polymers of various DP's have been studied using a membrane of 0.07 grams water per gram of dry PVA. Ben zene and ethanol solutions were used and the molecular weights ranged from 53,000 down to 2000. Ultra Centrifuge Variation. A newly developed ultracentrifuge cell obviates the complications encountered at the menis cus in conventional ultracentrifugation by the high diffusion and low sedimentation rate of the solute. This "synthetic bound ary cell" was described in a report b y H. K. Schachman and W. F. Harrington, University of California. A sharp stable boundary is obtained by layering one solution over another more dense solu tion, while the centrifuge is in operation, explained Dr. Schachman. By this technique, the sedimentation velocity method has been extended to molecular weights as low as 350. Sedi mentation constants of a number of low weight materials such as fraction A of insulin (molecular weight of 3 0 0 0 ) , vita min Bis (about 1 5 0 0 ) , /3-dextrin ( 1 1 3 4 ) , and sucrose ( 3 4 2 ) have been determined. The cell has also been used to form a boundary between solutions of two dif ferent concentrations of the same macromolecule, and differential sedimentation constants have b e e n obtained, he said. 3550
C&EN REPORTS: Society of American Bacteriologists
Calvin Postulates a Missing Step In Photoenergy Conversion Thiotic acid disulfide believed to react directly with w a t e r in preen plants or alcohol in model experiments SAN F R A N C I S C O . - W a t e r is now be lieved to b e the hydrogen donor in the primary photosynthetic conversion act. Until the present, this compound was not considered to b e a likely reagent in the initial conversion of the quantum into potential energy. Melvin Calvin, Univer sity of California, speaking before the 53rd general meeting of the Society of Ameri can Bacteriologists held here Aug. 10 to 14, said that current work shows that a two step reaction is involved and that water w a s the reactant in one of them. It has been known for some time that the unit of light energy or quantum is absorbed b y a chlorophyll molecule in photosynthesis. A large amount of en ergy, as high as 40,000 calories, is con tained in this unit and must b e converted to chemical energy in single operations in the plant. Until the latest research, how ever, it has not been possible to visualize a feasible physical and chemical pathway for this energy conversion. Dr. Calvin explained that in the con version process, thiotic acid, which has a 5-atomed ring with t w o adjacent sulfur atoms, accepts the energy from the chloro phyll w h i c h has acted as an antenna to receive it. The energy makes the thiotic acid disulfide very active and it is be lieved that this form reacts directly with water, in the green plant, or alcohol in the model experiments. In reports of earlier work, it was pointed out that the hydrogen donors could not b e specified but it w a s believed that water was not likely to b e one of them ( C&EN, April 27, page 1 7 3 8 ) . It appears now, Dr. Calvin said, that the reaction between the thiotic acid disul fide and water requires an amount of energy approximately the same as that available from the light quantum, or 30,0 0 0 to 4 0 , 0 0 0 calories. The product of the reaction has been shown to be a thiol sulfenic ester in the model experiments and is believed to be a thiol sulfenic acid in nature. Sulfenic acids are sulfur ana logs of hydrogen peroxide and are very unstable or have a high energy content. T h e energy of the quantum is thus trapped and fixed as chemical energy. The speaker proposed that by a dismutation or interchange of groups be tween two molecules of sulfenic acid, one molecule is reduced to a dithiol, a power ful reducing agent which could drive the necessary reductive steps in carbon di oxide reduction. T h e other molecule is
CHEMICAL
Joshua Lederberg ( l e f t ) , associate profes sor of geneHci at t h e University of Wis consin, receives congratulations from Gail M. Dack, president of SAB ? after formal presentation of t h e E l i O i l y Award oxidized to a system near the level of hydrogen peroxide from -which the oxygen evolved by green plants could ultimately be derived. Though further work will b e necessary to establish the truth of this theory of photosynthesis, Dr. Calvin be lieves that it suggests a mechanism by which the energy o f the quantum could be used to split a water molecule to give oxygen and the reducing power necessary for the conversion o f carbon dioxide into sugars. In experiments thus far, alcohol has been substituted for water as a result of the rapid changes i n t h e ?.Hd-water combination. Cortisone Speed-Up. Recent discover ies in the field of steroid microbiology are making the transformations of steroidal saponins into corticosteroids a simple proc ess, according t o B. A. R u b i n and his co workers, C. Casas-Campillo, B. Arreguin, F. Cordoba, and A. ZafFaroni, all of Syntex, S. Α., Mexico City. The steroidal saponins are complex structures consisting of a carbohydrate attached to a kind of steroid called sapogenin. They are found in the Mexican w i l d yams, and most of the known sex hormones and cortico steroids have been synthesized from plant sources. These workers have found sev eral organisms which selectively utilize the sugars leaving behind t h e sapogenin. Other bacterial transformations change the sapogen into derivatives more closely re lated to the mammalian hormones cutting down materially in the number of chemi cal processes normally required in the usual synthesis.
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Another new development using
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HARMON colors 3551
THE CHEMICAL WORLD THIS WEEK Importance of the process lies in the fact that hormones other than cortisone can he economically produced by this microbiological method. Compound F , or supercortisone, for example, can be pro duced in good yield. At t h e present time, this compound costs approximately five times as much a s cortisone, O r . Rubin told a group of listeners after h i s talk; within a year, h e predicted, it will cost only 50% as much as cortisone as a result of the greater e c o n o m y in the n e w process. Sized Dexf-ran. T h e size of dextran molecules obtained from bacterial culture in the commonly u s e d process results in molecules ranging in size from several thousand to many millions in molecular weight. I n the past, it has been necessary to degrade t h e crude dextran obtained from a normal feimentation by means of acid or ultrasonic v i b r a t i o n s in order to get a product h a v i n g a molecular weight of 75,000 ± 25,000, which is satisfactory for clinical uses. H y m a n Nadel, Chester I. Randies, ancl Grant L. Stahly, Obio State University, have found a new process for producing dextran in the desired molecular weight range. T h e y believe that the technique wll contribute greatly in producing greater quantities of clinical dextran using the same facilities now available. The synthesis of dextran was controlled by regulation o f three factors. T h e rate of bacterial growth is lowered by reducing the quantity o f nutrients available t o t h e organisms, specifically the yeast extract and casein hydrolysate. T h e sugar con centration of t h e bacterial culture medium is increased t o 3 0 % . A dextran primer is a d d e d to t h e culture medium. T h e primer serves a s a regulating mechanism for the dextran synthesis. B y varying t h e quantity and molecular size of t h e primer, large quantities, u p to 349^ of the total dextran recovered, have been w i t h i n t h e desired molecular w e i g h t rangeCell D a m a g e S t u d i e s . The over-all problem confronting a n y o n e w h o is in volved i n the study of t h e biological ef fects of ionizing radiation i s to determine how a process that affects less than one molecule in Ι Ο million can kill or m u t a t e a cell. T h e approach of W . Dexter Bel lamy, a n d coworkers at General Electric, has been to isolate individual components and study the radiation of these with t h e intention of exrtrapolating back to t h e in tact cell. These workers h a v e u s e d high velocity electrons in experiments wtiich show that in dilute solution the indirect e f f e c t absorption of the energy "by t h e solvent and subsequent transfer to the biological molecule—is o f great importance. In a natural e n z y m e system, however, such as tyrosinose in apples, the large a m o u n t s of extraneous materials p r e s e n t make t h e ac tion largely direct. This w a s shown b y im mobilizing the solvent b y freezing before irradiation. Bellamy s a i d t h a t w o r k at CE sub stantiates that of o t h e r s iii showing that
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the killing of bacteria such as Escherichia coli B/r is not dose rate sensitive. T h e r e fore, he said, it seems reasonable to as sume that a chemical chain reaction is not involved in the process. Studies on desoxynucleoproteins irradi ated in solution and a s precipitated fibers indicate that a combination of differential solubility a n d a small n u m b e r of breaks d u e to irradiation greatly magnify the physical and chemical results of radiation. A w a r d s . Joshua Lederberg, associate professor of genetics at t h e University of Wisconsin, received t h e Eli Lilly Award in bacteriology. The award is given an nually to a bacteriologist under 35. Dr. Lederberg originally demonstrated that genetic recombinations of well-defined characteristics take place in E. coli. T h e properties concerned were of biochemical nature and his work caught the attention of both geneticists a n d biochemists. Gail M. Dack, president of SAB, also presented t h e 1952 Commercial Solvents Award in Antibiotics to Ibert C. Wells, Edwin E. Hays, E . A. Doisy, and William L. Gaby, all formerly of St. Louis Univer sity, for research started in the early days of World W a r I I . T h e group developed an antibiotics series k n o w n as Pyos.
INDUSTRY Interhandel U r g e s Return of G A F ; Justice Summons Stockholders Plans for the disposal of its 9 0 % fi nancial interest in General Aniline & Film Corp., by t h e Swiss company, Interhandel, w e r e outlined to a g r o u p of editors and bankers in New York on Aug. 18, by W a l ter Germann, Interhandel president. H e said that according t o a plan submitted to t h e Alien Property Custodian who seized the G A F property in 1952, Interhandel would receive $60 million for the com p a n y from Blair Holdings Corp., San Francisco, and would probably reinvest half of that in American enterprises. H e said the "in competent govern ment management" has stunted t h e na tural growth of G A 1 \ T h u s t h e company's sales have increased only 5 5 % since 1946, while the 32 chemi cal companies whose shares are listed on W . Germann the N e w York Stock Exchange have m a d e average gains of al most double that figure. " M a n y other chemical companies de veloped synthetic detergents after the war, b u t the management of G A F missed the boat." Other potential expansions neg lected were in inherent colorings, phar maceutical chemicals, fluorides and fluorocarbons. and silicones, Germann said. H e remarked further that G A F was seized in 1942 "on t h e mistaken theory"
CHEMICAL
that it was the property of I G F a r b e n , a G e r m a n firm. As its principal supplier of intermediates, I G F a r b e n naturally h a d a close business relationship w i t h G A F . However, the real control a n d ownership of G A F w a s exercised b y Interhandel, a Swiss corporation governed b y a p r e dominantly Swiss board of directors and d o m i n a t e d by Swiss and American bankers, G e r m a n n said. Interhandel was originally k n o w n as I. G. Chemie, h e said, w h i c h has led to some confusion of identity with IG F a r b e n , since both companies h a v e t h e first t w o initials in common. Interhandel's lawsuit for t h e return of its vested shares in G A F has b e e n pending before the U. S. District Court i n W a s h ington since 1948, and t h e court will re convene on the matter again on Oct. 16, unless the Government m e a n w h i l e grants the r e q u e s t of Interhandel to liquidate its interests. Failing favorable settlement, an appeal will be taken to t h e Supreme Court, G e r m a n n indicated. . An order was issued Aug. 14, by the Justice Department, Office of Alien Prop erty, instructing all nonenemy stockholders of I n t e r h a n d e l to enter a n a p p e a r a n c e in the suit for return of G A F b y Jan. 1, 1954. Although Interhandel claims to b e Swiss, the Justice D e p a r t m e n t contends t h e hold ing c o m p a n y is merely a d u m m y for I G F a r b e n , a n d hopes t o determine h o w m a n y n o n e n e m y stockholders exist a n d how much Interhandel stock t h e y own. None n e m y stockholders will receive their pro rata s h a r e from any sale of G A F .
Linde Seeks Tariff Protection For Its S t a r Sapphires A complaint asking for exclusion of entry of synthetic star sapphires and rubies was filed with t h e Tariff Commis sion A u g . 11, b y Linde Air Products Co., a division of Union Carbide a n d Carbon Corp. L i n d e originally b e c a m e producers of synthetic sapphires at the beginning of W o r l d W a r II when t h e E u r o p e a n source of synthetic rubies and sapphires, neces sary for precision watch mechanisms, was cut off. W i t h the cessation of hostilities, E u r o p e a n synthetic sapphires once again a p p e a r e d in t h e U. S. market a n d at a lower price. L i n d e continued its research and developed a w a y of making starred sapphires for which t h e y received U. S. p a t e n t N o . 2,488,507. U n d e r this patent they h a v e been able t o make synthetic starred sapphires for about $5.50 whereas a natural star sapphire of equal size costs about $6000. L i n d e is now charging that star sap phires manufactured b y substantially the same process as described u n d e r their p a t e n t a r e entering this country from E u r o p e a n d are infringing not only on their U. S. market but also on their pat ent. Since these sapphires can b e pro d u c e d in »a cheaper labor market, they can undersell Linde's product h e r e . According to t h e testimony of Max Duraffourg, o n e of Linde's N e w York
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