THE CHEMICAL WORLD THIS WEEK
SO, REMOVAL:
Cheaper Process Piloted
Hercules' Turner Plenty of room for two place the company in competition with its licensee, B. F. Goodrich Chemical Co. In 1964, Hercules granted a license to the Cleveland, Ohio, company to make, use, and sell epichlorohydrin-based rubbers. Hercules holds broad patent rights for the manufacture of these elastomers. The first two members of the family to be made by Hercules will be a homopolymer (Herclor H) and a copolymer with ethylene oxide (Herclor C ) . Both compounds exhibit outstanding resistance to ozone, heat-aging, chemicals, and solvents, according to Robert Turner, manager of the development rubber division of the company's pine and paper chemicals department. Herclor C differs from the homopolymer Herclor H in having higher resilience and better flexibility at low temperatures. However, Mr. Turner points out, a recent development which led to lower viscosity raw polymer has enhanced the processability of the copolymer. Thus, Herclor C has a Mooney viscosity in the range 50 to 60 and offers the advantage of easier extrusion and calendering, he adds. Applications for the epichlorohydrin-based rubbers include automotive and aircraft parts, seals and gaskets, wire and cable jackets, adhesives, packings, hose and belting, and rubber-coated fabrics. Although both companies decline to give any specific information as to the size of the market for these elastomers, each indicates that the number of uses is increasing. These uses, says Goodrich, require a combination of oil resistance, ozone resistance, low-temperature flexibility, and impermeability to gases. As such, the Ohio company adds, these epichlorohydrin-based rubbers are competing favorably among special-purpose oil-resistant polymers, such as acrylics, nitriles, and Neoprenes. 22 C&EN SEPT. 9, 1968
An economical process to remove sulfur dioxide from waste gases is now in the pilot plant development stage at Princeton Chemical Research, Inc., Princeton, N.J. The PCR process converts sulfur dioxide to pure sulfur, which has been in short supply but which now may start to flow more freely (C&EN, Sept. 2, page 10). The PCR process is more economical than other sulfur dioxide removal methods now available, says Dr. Norman J. Weinstein, PCR's director of engineering and development. "Our economic estimates for an 800Mw. power plant operating at 90% power factor, burning 3% sulfur coal indicate a total capital requirement of $5.42 million or $6.77 per kw. and operating costs before sulfur credits of $2.17 million per year or 98 cents per ton of coal," Dr. Weinstein tells C&EN. These estimates are significantly lower than corresponding estimated costs for the molten carbonate, alkalized alumina, catalytic oxidation, and Reinluft processes made on the same basis (C&EN, July 8, page 13). In PCR's sulfur dioxide removal process, hydrogen sulfide reacts with the sulfur dioxide-containing stack gas at 250° to 300° F. in the presence of an undisclosed catalyst to produce sulfur and water. Some of the sulfur is recovered and then reacted with methane and water at a high temperature in the presence of another undisclosed catalyst to produce carbon dioxide and hydrogen sulfide for reaction with more stack gas. PCR is building a continuous, integrated pilot plant to demonstrate the technical and economic feasibility of its sulfur dioxide removal process. The company has recently received $270,700 from the National Air Pollution Control Administration of the U.S. Public Health Service to finance the pilot plant. The new process will solve a critical air pollution problem, and the sulfur recovered in the process will pay its own way, Dr. Weinstein expects.
POPULATION CONTROL:
Outlook Remains Grim The twin problems of too many people and too little food in developing nations evoke much pessimism and little optimism in today's scientists. This was apparent last week at the 19th Annual American Institute of Biological Sciences (AIBS) meeting of Biological Societies at Ohio State University, Columbus. Dr. Harold F. Robinson, executive director of the President's Science Advisory Committee Panel on
World Food Supply, notes that a tremendous amount of capital and technical involvement from developed and developing nations alike will be required to bring this fast growing problem into check. "The attitude of the present Congress toward providing the technical assistance needed is demonstrated in the foreign aid bill, which is at the lowest level in modern history/' Dr. Robinson says. The U.S. and other developed nations must take the leadership in reversing the logarithmic phase of population growth, says AIBS president William McElroy, who is also chairman of the Population Committee of the National Academy of Sciences. Toward this end he suggests: • Appointment of a special assistant to the President to seek ways and means to thwart world population growth and increase food supplies. • Establishment of worldwide institutions in which family planning and population control advice are coupled with maternal care services. • Changing of our farm policygearing it to maximum production and using excess food to provide emergency food assistance to stave off disaster while hungry nations build their own food producing capability. • An all-out effort be made to supplement traditional land-based agriculture by farming the oceans. • Family planning and principles of population dynamics be made a part of all secondary school curriculums. • Discussions on a worldwide basis of the merits of family planning vs. population control. We are faced, Dr. McElroy, says, with the problem of reducing the growth of population essentially to zero, where the number of deaths equals the number of births. Family planning, he says, has not had and will not have any significant effect on the growth of world population. Possible actions to achieve population control include legalized abortion in all states, incentives in the form of fees from the Federal Government to postpone marriages till a given age, and penalties in the form of tax burdens for every child beyond, say, three, in any family. Approaching the overall problem from the food angle, Dr. H. David Thurston of Cornell University points out that today's food crisis is largely faced by people living in the tropics, the subtropics, and contiguous areas. Failure to recognize the food crisis as a tropical problem, he says, often deludes people into thinking that our temperate zone agricultural technology can be transplanted directly. Education in farming techniques is one important step that can help solve the tropics' problem, he says.
