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Pattern for Progress Some of our major chemical processes can trace their start to developments first reported in l/EC. This month the editors look back on the commercial process for sulfamic acid (1938) and pentachlorophenol as a w o o d preservative (1939)
Sulfamic Acid — 1938 I ou are sitting in a restaurant having dinner. You notice the p a r t y at the table next to yours. T h e y are through with their dinner a n d are just being served coffee. T w o of the m e n have theirs black, one puts cream and sugar in his, while the fourth m e m b e r at the table pulls a little bottle from his vest pocket and sprinkles a few drops of liquid in his coffee. T h e m a n has a diet problem and he is using a dietetic liquid sweetener such as Sucaryl, Cylan, Sugarfine, Sweeten-It, or any n u m ber of others. Now turn the clock back 20 years. In J u n e 1938 I / E C published an article: Sulfamic Acid—A New Industrial Chemical. T h e process outlined is the same one used today for making sulfamic acid. And sulfamic acid is the key ingredient in making artificial sweetening agents similar to the one mentioned above. Author of the 1938 article was M a r t i n E. Cupery of the D u Pont Co. Dr. Cupery, still with D u Pont, w r o t e : " A new process has been developed by which sulfamic acid is readily prepared from urea and fuming sulfuric acid. T h e process appears to be suitable for large-scale production, so t h a t sulfamic acid is now potentially available as a new industrial raw material." This article set the pattern for progress in m a n y fields. I n addition to the use of sulfamic acid in the rapidly growing dietetic sweetener business, the chemical is finding use as a flame retardant, weed killer, softening agent for p a p e r a n d textiles, metal 28 A
cleaner where it is used to remove scale from heat transfer coils, a n d in making eletroplating salts. Nickel, for example, can be electroplated very easily when in the form of nickel sulfamate. O t h e r uses of sulfamic acid which, incidentally, were predicted in the article by Cupery a r e : destroying nitrides in making dyes, organic intermediates, a n d / o r a standard of reference in acidimetry. T h e process for making sulfamic acid, patented by D u Pont, is based on the reaction of urea with fuming sulfuric acid u n d e r controlled conditions. However, before D u Pont had a chance to get into production of the chemical for commercial uses, the Government stepped in a n d required that total o u t p u t of the chemical be turned over to armed forces for treating equipment, such as clothing and canvas. Peace brought a slow return to normalcy and commercial production. Expanding industry of the late 1940's waited for the workhorse on which to expand their markets. But it was not until 1950 that D u Pont started producing calcium cyclamate, base component of Cylan, D u Pont's sweetening agent. T o d a y , D u Pont is the biggest producer and user of sulfamic acid. Several other smaller companies—for example, the L a m o t t e Chemical Co. and G. Frederick Smith Chemical Co.—buy sulfamic acid from D u Pont and further purify it for use as an analytical reagent. If past performance, based on the unique properties of sulfamic acid, can be used as a barometer for predicting future prospects, we think there is only one direction in which this compound's sales curve will g o — up.
INDUSTRIAL AND ENGINEERING CHEMISTRY
Pentachlorophenol for Wood Preservation-1939 T a k e a trip on a train, and chances are the railroad crossties you are riding over have been preserved with pentachlorophenol. O r look at the millwork in a building. It is probably preserved with pentachlorophenol too. Pentachlorophenol was first prepared in 1841, but it was not commercially available until 1936. And it was used very little as a wood preservative until after 1939, when T . S. Carswell and I r a Hatfield evaluated its use as a wood preserving chemical. T h e results of the studies these two m e n m a d e served as the blueprint for the wood preserving industry's use of the chemical—a blueprint first p u b lished in I / E C in November 1939. T h e p a t t e r n for progress was set, not by discovering a basic chemical process as with sulfamic acid above, but by simply calling industry's attention to a chemical valuable for a specific end use. At the time, the use of chemicals for preserving wood and wood products was not new. But m o d e r n conditions created a wider d e m a n d for preservatives as well as a need for improved properties over those possessed by chemical treatments then available. It was against this background t h a t Carswell a n d Hatfield began their studies and concluded with: " T h e physical and chemical characteristics of pentachlorophenol recommend it for the field of wood preservation." T h e recommendation that pentachlorophenol is a potentially valuable wood-preserving chemical was accepted by industry. Against fungi and insects, it has consistently shown high effectiveness and is being used for this purpose with ever-increasing confidence. And as usage experience builds u p , pentachlorophenol solutions may come to be accepted as equal to or even better t h a n coal tar—creosote for protection against fungi and insects.
