Giants of the Past:
Ralph H. Potts (1900-1981)
Ralph H. Potts, the father of the oleochemical industry, was born July 31, 1900 in Reading Pennsylvania. In 1922, he graduated from Lehigh University with a degree in chemical engineering. After much searching he decided on a position with Armour Packing Company in Chicago. This decision was met with considerable dismay by his mother who believed Chicago to be inhabited by gangsters and Indians.
Potts felt the work in Chicago to be less than challenging and left after only six months. Apparently the only good thing to come of his employment at Armour was meeting his future wife, Nancy, who was employed as a chemist there. After spending only nine months at Sinclair, Potts decided to return to Armour near the end of 1923. His experience at Sinclair, where he was exposed to petroleum cracking and refining, proved invaluable upon his return to Armour Auxilliaries, one of the many non-food divisions of Armour. A major challenge was to convert meat packing wastes into value added products, including the conversion of tallow and greases to quality fatty acids for the manufacture of soap, greases and candles. This was accomplished by hydrolysing the triglycerides to glycerine and fatty acids followed by distillation. Since tallow and grease were selling for two cents a pound, any upgrading could be very profitable. From his experience at Sinclair, Potts realized that fatty acids could be fractionally distilled and certain fractions could be of more value. For example, low boiling fractions were inferior to high boiling ones in soap manufacture. After proving the point, he also reasoned that fractionation could upgrade lower grade feed stocks for soap manufacture.
However, convincing upper management to build a fractionating unit proved difficult. The resourceful Potts found a way to get the job done. Disguised as parts for pump repairs, Potts submitted work orders to the machine shop for his fractionating still. Fashioned from a brass pipe filled with broken glass and heated by a natural gas burner, the unit did not last long but proved to be effective (circa 1925).
At the beginning of the great depression, Armour was faced with a difficult decision of whether to replace the old, simple cast iron stills or get out of the fatty acid business altogether. However, because they were making profits on distilled fatty acids, it was decided that capital expenditures on new equipment was justified. The use of laboratory data and the 1925 prototype allowed construction of new fractionating columns. The unit, completed in 1933, was beset with start up and corrosion problems. But, by 1935 was in full operation and producing high quality fatty acids. Although the new stills were working well, it became apparent that the supply of raw materials greatly exceeded the demand for the distilled acids.
To overcome this problem, Armour initiated a program to find new uses for animal fats. Under the direction of Victor Conquest and A. W. Ralston, who headed Central Research Laboratory, the new program got an unexpected boost because Potts and Conquest lived in the same apartment building. Over drinks and card games, the two men exchanged ideas. Ultimately, the Central Research Facility and Armour Auxilliary were combined. This initial project involved conversion of fatty acids to rubber precursors for golf balls. Although the idea did not work, they learned that the hydrocarbon chains of fatty acids could be modified with catalysts and the carboxyl group could be converted to nitrites through reaction with ammonia and, in turn, could be converted to amines. By 1938 the first commercial shipment of fatty amine was made. The fatty amine business soon became so successful that the units could not keep up with demand. Armour authorized construction of a new plant in McCook, Illinois, which did not become fully operational until 1951because of World War II, numerous cost overruns and delays. This frustrated Potts and others immensely. An Armour Food executive reportedly said he would trade Potts all his patents and the new plant for six sausage plants.
Norman Sonntag believed that, of his many patents relating to the distilling of fatty acids and tall fatty acid distillation, three stood out. The first (U.S. Patent 2,054,091 issued Sept. 15th, 1936) related to a process for fractional distillation employing reflux in which heated and evolved vapors are passed through a series of successive heat exchanging pools of fatty acids with recirculation of the low boiling point vapors back to the pools as reflux liquids and elimination of low boiling point fatty acids as the upper pool and high boiling point acids at the bottom. This initial patent, with co-inventor John McKee, formed the basis for the next patent (U.S. 2,224,925 issued Dec. 17th, 1940), which was the first disclosure of the complex distillation method known as the Potts-McKee process. Basically, it outlined and pin pointed the combinations process conditions necessary for the fractional distillation of fatty acids. A third patent (U.S. 2,224,986 issued Dec. 17th, 1940) outlined modifications of the distillation process to include deodorization of edible oils and was intended to protect potential application of the Brood invention. Potts’ work revolutionized the industry and caused a flurry of patent activity that would not have been possible had he not laid the groundwork.
A second area in which Potts made a major contribution involved fatty nitrile and amine technology. Over the period 1943-1967 a number of patents were issued covering methods to prepare nitriles via a two-step process through liquid phase ammonolysis and subsequent dehydration (U.S. Patent 2,314,894 issued Mar. 30th, 1943). Others described improvements to the process including use of high temperatures in heat exchangers to maintain the exothermic nature of the ammonolysis dehydration reactions (U.S. Patent 2,414,393 issued Jan. 14th, 1947). A further improvement was patented by demonstrating that the liquid phase reaction could be carried out in separate zones.
By 1950, Potts detailed how fatty nitriles could be separated from ammonia, water and hydrogenation inhibiting impurities by passing the mixture through pools of nitriles, water and ammonia to vaporize the latter followed by condensation of the nitrile. Other important contributions to nitrile/amine preparation included a process to prepare both fatty amines and nitriles simultaneously by ammonolysis of fatty acids, and a process to prepare either nitriles or amides by countercurrent passage of ammonia through liquid fatty acids. No catalyst is required.
In 1952, Potts patented the basic nitrile process used by Armour at Morris and McCook. The process is essentially a continuous 3 zone method where, in the first zone, liquid fatty acids are contacted with ammonia to yield amides. In the second zone amide is converted to about 80% nitrile and in the third zone a catalytic vapor phase reaction yields high purity distilled nitriles.
Potts was the author of about 20 publications mostly appearing in JAOCS and held 32 United States patents, a number of which were licensed in England, Norway and France. Potts was a lecturer at numerous AOCS short courses on fatty acids held during the 1950’s. He loved to travel, was an ardent photographer, fisherman and miniature railroader. Potts had two sons who followed in their father’s footsteps as chemical engineers. In 1959, the North Central Section established the Alton E. Bailey Award to honor those who have made significant contributions to fats, oils, lipid and related materials. Potts received the award in 1960. In 1970, he was made an honorary member of AOCS. Other honors accorded to him include election as a fellow in the American Institute of Chemical Engineers in 1973. In 1982, under sponsorship from Armak, AOCS established the Ralph H. Potts Award, which honored a graduate student working in the area of fats, oils and their derivatives. In the early 1990’s, under sponsorship of AKZ0 Nobel, the award became the Ralph H. Potts Memorial Fellowship Award consisting of a $1000 honorarium; the research so honored must involve fatty acids and their derivatives including long chain alcohols, amines and other nitrogen compounds.
Ralph Potts passed away January 2, 1981 at his winter home in Florida. It was said of him, “Without a doubt, men like Ralph H. Potts don’t come along every year. The oleochemical industry certainly owes this unique and talented man an enormous debt of gratitude for his monumental contributions.” (Norman Sonntag, 1984)
Acknowledgement: This document was first published in Inform, March 2004, Vol. 15(3) p. 168.