wise, a great psychological barrier to male contraception. This may be the biggest practical problem of all in connection with male contraception. Draconian agents, used in the "Orwellian sense," have great appeal to many people but they will probably have to be rejected on practical grounds. Dr. Djerassi says that their development would be absurd. One reason for rejecting the Orwellian approach is that any agent introduced, for example, into the water supply would have to be active in either the male or the female, but only during their reproductive years, and would have to be active over a very great dose range. It would also have to be tasteless and specific for man alone. If such an agent were used as a food or added to food, it would have to be incorporated by the producer rather than by the consumer. Even then, any dissenter could simply eliminate the food from his intake and effectively circumvent the additive. Water would appear to be the only logical vehicle for administering a chemical contraceptive to an entire population. The question of side effects would probably remain unsolvable. Any Orwellian substance would have to be considered as an environmental contaminant, particularly if the side effects were concentrated in particular groups of people. According to Dr. Djerassi, any system of chemical contraception in the future will require a close coordination of the efforts of the drug industry, government, and the academic research laboratory. Each has a natural and important role to play and none should be excluded from this most important enterprise. The pharmaceutical industry is the source of most of the modern prescription drugs. Dr. Djerassi recalls no instance where all of the development work for a given drug was performed by a government laboratory, private research laboratory, or a medical school. The industry is also probably the best means of getting new drugs to the users. The Government is the coordinator in the development of a new drug and is responsible for seeing that the development follows the necessary legal and ethical procedures. The university and the private foundations are the sources for the expert consultants and specialized knowledge.
Corn syrup from immobilized enzymes AG & FOOD—Changes in food preparation methods and in diets are leading to major changes in sources and processing of sweeteners consumed in the U.S. Currently heading up the processing changes is use of immobilized enzymes to convert cornstarches to highfructose corn syrup. This syrup goes largely to consumer products such as carbonated beverages and baked goods. 36
C&EN April 23, 1973
High-fructose corn syrups are produced in volume by Clinton Corn Processing, a division of Standard Brands, Clinton, Iowa, and by A. E. Staley Mfg. at a plant located at Morrisville, Pa. These plants and one to be built by CPC International at Englewood Cliffs, N.J., use a basic process involving immobilized enzymes covered by U.S. Patent 3,616,221, assigned to the Agency of Industrial Science and Technology, Tokyo, Japan, Dr. J. M. Newton of Clinton Corn Processing points out. Standard Brands has the exclusive U.S. license with the right to sublicense. The principal product of Clinton's plant is a water-white solution of saccharides containing 50% dextrose and 42% fructose, Dr. Newton says. The plant process uses an immobilized glucose isomerase derived from one of the several species of Streptomyces capable of isomerizing dextrose in corn syrups to fructose. The isomerase is put into reactors and a solution containing dextrose is pumped continuously through the reactors. The isomerization occurs rapidly because of massive concentrations of glucose isomerase. Refining is by conventional processes of filtration, carbon decolorization, ion exchange deionization, and concentration to the desired solids content. On a solids basis, the product is equal in sweetness to sucrose, according to Dr. Newton. The immobilized enzyme has a long life—hundreds of hours, according to Dr. Newton—and can be removed from the processing system by isolating a single reactor. Variables such as pH, temperature, and feed rates are controlled automatically by an on-line process control system.
Better methods to treat sewage foreseen WATER, AIR, AND WASTE—The
effectiveness and safety of chlorination in the treatment of effluent from sewage plants have been opened to question in studies being conducted in Michigan. Dr. Jack F. Mills of Dow Chemical told the ACS meeting in Dallas that better treatment is foreseen with improved disinfectants. Recent disclosures by the Michigan Water Resources Commission claim that chloramines produced in the reactions of chlorine with ammonia in sewage effluents produced fish kills downstream, at chloramine concentrations below one part in 10 million. The culprit is ammonia, which is always present in sewage plant effluents. Ammonia is also known to greatly diminish chlorine's bactericidal and viricidal power. There is some evidence that colifortn bacteria and polio-H virus may not be entirely eliminated in some effluents although that evidence is not conclusive.
One possible alternative that appears to solve the problem is substituting bromine chloride for the chlorine added in sewage treatment, Dr. Mills says. Unlike chlorine, bromine chloride reacts with ammonia to form bromamines, which rapidly decompose in the effluents. Chloramines are much more stable and longer lived. The use of bromine chloride thus eliminates both chloramine and bromamine residuals downstream and offers no threat to marine life. Bromamines also have better bactericidal and viricidal properties than their chlorine counterparts. Ammonia also might be reduced through nitrification, a biological oxidation process that removes about 90% of the ammonia, Dr. Mill says. The remaining ammonia can then be oxidized with excess chlorine without producing toxic chloramines. However, the cost of nitrification and additional chlorine would be high compared with other alternatives, including chlorobromination. At Wyoming, Mich., a study is under way to evaluate the alternatives to chlorination. The study, funded by the Environmental Protection Agency, will gather data on ecological hazards from sewage chlorination as well as from chlorobromination, ozonation, and dechlorination with sulfur dioxide. Dow claims that bromine chloride should be competitive with the other alternatives. However, future costs to disinfect sewage will probably be higher if chlorine is replaced with any alternatives.
High-energy arcs used to make hydrocarbons FUEL—Although electric arcs and plasmas have been studied for many years as potential synthesis reactors, only recently have arcs exhibited much virtuosity in the kinds of compounds produced. One new attempt at hydrocarbon synthesis in high-energy arcs was described at Dallas by Prof. Samuel Korman of Columbia University chemical engineering research laboratories. In Prof. Korman's system, the principal reacting components are carbon and hydrogen. Conventional arcs, when used for chemically reacting systems, depend on the radial addition of reactants to the arc column. The mechanism for the energy transfer in such a system is radiation and convection in the arc. This is difficult to accomplish because the energy transfer limits practical temperatures to under 2500° C. There is also a major problem in maintaining the stability of the arc. In the new type of arc used by Prof. Korman, the gaseous reactants actually form the plasma itself by admitting the reactants to the cathode end of the plasma column. This is done by using an unusual concentric cone cathode. The
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system permits much higher temperatures, sometimes exceeding 10,000° K. The high-intensity arc has been studied for some time but only recently have there been attempts to use it for hydrocarbon synthesis. Prof. Korman calls his system the fluid convection cathode (FCC). Prof. Korman used the FCC to study the synthesis of hydrocarbons. From 10,000° to 20,000° K., the hydrogen in the feed is monatomic and impinges on the carbon anode at its sublimation temperature of about 4000° K. in the arc crater. Gas samples drawn from this region during operation are found to contain hydrocarbons. The composition of the hydrocarbons depends on the flow rate of the hydrogen fed to the arc, the temperature, and the residence time of the arc effluent in the downstream hot zone. The composition of the confining wall also has an effect. Hydrogen, though always present in stoichiometric excess, causes a transition of the hydrocarbon product ranging from 100% acetylene at low flow rates, to mixtures of acetylene and methane with occasional amounts of propylene. At high flow rates methane is predominant. When steam is substituted for hydrogen in the FCC arc, the principal hydrocarbon component is methane. As the flow rate increases, acetylene predominates. A solid, pulverized petroleum residue fed in entrained argon into the FCC arc produces acetylene predictably under conditions corresponding to the analogous hydrogen feed. Dr. Korman believes that the results from his studies thus far indicate that the FCC arc may be useful in a number of applications in the gasification of coal and other carbonaceous feeds.
Fluorocarbon plastics from plasmas FLUORINE—A new technique for making poly(carbon monofluoride) (CMF), plasma synthesis, has been developed by Dr. Richard J. Lagow and his associates at Massachusetts Institute of Technology. He produces CMF in a fluidized plasma with graphite as the solid phase and fluorine as the fluidizing gas. The technique has several advantages over previous thermal methods, including lower temperature and lower energy needs. CMF, obtained from the fluorination of graphite, is the most thermally stable polymeric fluorocarbon known. It is indefinitely stable to 600° C. and stable for short periods to 800° C. Recent studies of the lubrication properties of CMF at Lewis Research Center of the National Aeronautics and Space Administration and at Frankfort Arsenal have excited new interest in the material. These studies show that CMF, as a solid lubricant under extreme conditions such as high and low temperatures and heavy loads, is very much superior to graphite or molybdenum sulfide. CMF also shows promise as a cathode material in high-energy batteries. One of the problems, though, is how to make the new material. Dr. Lagow's unusual synthesis is an example of the use of a fluidized plasma bed to prepare an industrially important compound. And it also demonstrates the advantages of a fluorine plasma in preparative fluorine chemistry. The gas temperature of the plasma in his technique is less than 150° C.— a much lower temperature than that used in other thermal approaches. The amount of energy used is much less than that required for a furnace of corresponding size maintained at 600° C. Also, it may prove easier to generate a large plasma than to keep a larger furnace uniformly in the narrow temperature range required for synthesizing snow-white CMF by thermal means.
Oil shale potential surveyed l&EC—With alternate energy sources looming larger in the future, industry is taking a harder look at their development. One source that appears to be among the easier to exploit in the short term is oil shale. Although the active lifetime of this source of oil and gas may be only a generation, it is ready for immediate development on a commercial scale. Oil shale really isn't a shale at all but a marlstone containing large amounts of organic matter. It may be pictured as an inorganic matrix in which an organic material resides, Dr. Arnold H. Pelofsky of Cities Service Research and Develop-
ment Co. told the meeting. The organic material is called kerogen. The relation of the kerogen to the matrix includes some primary valence bonding with the alkaline earth carbonates. Thus, the raw shale must be acidified before the kerogen can be removed. Acidification removes the calcite and dolomite portions of the shale. Also, some of the porphyrins in the shale may chelate with some of the minerals. Acidification circumvents this problem by removing much of the mineral content. Because kerogen has many polar sites, it is intimately mixed with minerals that are known adsorbents. These various types of bonds explain why a purely physical separation of the kerogen is so difficult. The compressive strength of oil shale is higher than most people suspect, sometimes up to 30,000 p.s.i. In fact, the compressive strength is more than sufficient to permit conventional mining of the material without incurring safety problems. Oxidation and degradation studies of kerogen indicate that at least two major types of compounds exist in the shale. One type is predominantly hydrocarbon in nature with straight chains, rings, and some heterocyclic structures that produce on processing most of the oil, wax, and resins by thermal degradation. The second type is essentially a heterocyclic material that is partially converted to oil on processing but to mainly hydrogen-deficient materials which, in turn, yield mostly carbon residues and gas. According to Dr. Pelofsky, extraction tests of kerogen from the Green River formation in Wyoming show that the material consists of 5 to 10% chain paraffins, 20 to 25% saturated cyclic structures, 10 to 15% aromatics, and 40 to 45% heterocyclic structures. The identification of the various types of compounds in the raw kerogen indicates the biological origin of the elements in the kerogen. Chemical analyses and the results of x-ray, infrared, and ultraviolet analyses of Green River kerogen all indicate that it is predominantly naphthenic. Pyrolysis of oil shale is probably diffusion limited, Dr. Pelofsky says. Heat must diffuse into the shale and the products must diffuse out of a structure that has essentially no pores. As pores develop during pyrolysis, when the products leave the shale matrix, the diffusion characteristics change. Although the pyrolysis kinetics are grossly first order, the quality of the products is a function of the temperature of pyrolysis. The higher the temperature, the more gas and aromatics are formed. Whether mineral content of the shale is involved in any way in the pyrolysis process isn't certain. However, the work of many investigators over the past 50 years shows that more product is recoverable as oil if the residence time is relatively short and the shale particle size is relatively small. April 23, 1973 C&EN
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