Wax Oxidation - Industrial & Engineering Chemistry (ACS Publications)

Wax Oxidation. B. H. Rosen. Ind. Eng. Chem. , 1960, 52 (1), pp 14–16. DOI: 10.1021/ie50601a023. Publication Date: January 1960. ACS Legacy Archive...
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B. H. ROSEN Cities Service Research and Development Co., Cranbury, N. J.

Wax Oxidation There is only one foolproof formula for avoiding disappointing research projects: DON’T DO ANYTHING!

ALMOST.

every company Ivhich has found itself the sad owner of a research project which has become a full-blown failure undergoes some soul searching as to what went wrong. In the case of the wax oxidation project at Cities Service: the chronology is of considerable .mportance in understanding the birth and death of the work. Cities Service had initiated some research work on oxidation of petroleum wax in 1937, the xrork being largely undertaken by a small group interested in the product for anticorrosion formulations. For this purpose wax oxidate was moderately successful and resulted in a semicommercial pilot plant ivhich could produce sufficient wax oxidate to satisfy the company’s market needs of the time. Research work was discontinued at the onset of World War 11: and the technical knowledge lay fallow till about 1948. Interest rose sharply in a wax oxidation process at this time for a number of reasons. Expansion of research \vas being undertaken and the technology of the company was being revieived exhaustively to determine fertile fields for research. The wax oxidation process seemed to be a good bet for research work. The reasons lvere threefold. First, there was a captive raw material supply in the form of fully refined, crude scale and soft waxes. Second, wax oxidate was rich in fatty acids Lvhich are one of the major cost constituents of grease, and as a grease manufacturer and marketer it was an advantage to have a low cost supply of fatty acids. Third, there was some experimental work already on hand which indicated that the process \rould be technically feasible. So it appeared that all the elements necessary for success-rair materials, captive market, and know-hoiv-were on hand. Economic Evaluation However, it is customary to conduct an economic evaluation of research projects, and, because of the anticipated cost of research for this project, a detailed study

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of the economics \vas made. The price of fatty acids from 1935 to the middle of 1948, when the study was being made, was obtained. The study covered not only stearic acid, which appeared to be the target, but other fats and oils which were used as fatty acid sources for grease. For stearic acid the price was 10 cents per pound even during the depression years, had stabilized during the war years to about 15 cents a pound, and shortly after the war had risen to as high as 32. cents a pound. Although the current trend showed the price dropping, it was felt that it would probably stabilize at the 15 cent a pound level. The market searchers were sophisticated enough to evaluate the effect of other factors upon the potential price of fatty acids. At this time the influence of detergents upon the sales of soap and consequently on the demand for fatty acids was beginning to be felt. At the time the project was undertaken, soap sales Ivere running about 3 billion pounds a year and synt1iet:c detergent sales on 100% active basis Lvere running about 3 million pounds a year, or roughly 0.170 of soap sales. It was concluded that detergents \rould not pose a serious threat to fatty acids in soap for some time to come. One must remember that there ivere soap companies who underestimated the impact of detergents upon the soap market, so that it was not surprising that the evaluation of the effect of detergents upon soap was not all that it might have been. The company \rent even further in trying t o determine what might affect fatty acid price and supply and studied some competing processes for the production of fatty acids. Among these were the Fischer-Tropsch and Oxo processes. The economic data showed that the wax oxidation process should be quite competitive with both. All this market study preceded any research work which was to come on the process. Yet, evaluation of the fruitfulness of such a research project was still not complete. The price of the raw

material had to be examined to see whether a radical variation in this major factor might be expected, which could, of course, affect the economics adversely. Early experimental work prior to the war had utilized a crude scale wax, and the same feed stock was to be used. So the market searchers went back to 1934 and checked the price at Nexv Orleans for \vhite crude scale wax, as the wax supply would come from near this point. The price history is similar to that for fatty acids in that it was at a low value prior to the war, stabilized during the Lvar, \vent up quite rapidly after the war, and was currently receding to some reasonable value. I t was estimated that crude scale wax would stabilize at 5 cents per pound. The bare economics thus far were to sell the product for 15 cents a pound and pay 5 cents a pound for raw materials, allowing 10 cents to cover operating costs, plant amortization, marketing costs and, it was hoped a reasonable profit. Still no research work had been undertaken, for the analysis was not complete without a plant investment cost estimate. To do this, the company had to depend upon the rather meager data available on yields, O i l the estimate of laboratory research people for a potential process, and on some long range guesses as to \rhat might ultimately be expected in the way of distribution of products and product quality. Some of this guewvork was simplified by taking some of the old wax oxidate, extracting the fatty acids from it, and using them to make grease according to then-existing formulations. Some fairly good greases werr madenothing earth-shattering, but certainly marketable greases of competitive qualiry. The organic chemists, whose imaginations \cere fired by the series of lovely organic compounds present in wax oxidate, enthusiastically believed that research could produce far superior acids in much greater quantit). than had been obtained heretofore. Such enthusiasm can create some of the best research accomplishments.

P l T F A b L S IN COMMERCIAL D E V E L O P M E N T

New York market prices for fats, oils, and fatty acids

However, the company tempered this enthusiasm with good judgment, engineered the process on paper, and estimated a plant investment. Using this figure, it was possible to calculate plant depreciation, operating costs, and maintenance and determine whether there was a profit in undertaking research on wax oxidation. The final answer was that there appeared to be a valid incentive for proceeding with the research program, and the company did. Research Begins

A research team was assembled consisting of chemical engineers, organic chemists, physical chemists, and analytical chemists to pursue the research work. T h e total number of people was about 12, of whom three had extensive experience with the batch oxidation of wax for use in anticorrosion product work. Gross analysis of wax oxidate showed three broad classes of products: aliphatic acids, hydroxy and keto acids, and alcohols, along with unreacted wax. I t must be reiterated that the basic interest in wax oxidation was for the production of fatty acids for grease making. One of the assumptions in the economic study was that the alcohols produced in wax oxidation could be reoxidized to fatty acids. I t was assumed that with suitable selection of catalysts and operating conditions this could be accomplished. The hydroxy and keto acids present were unsuitable for grease, so the first task assigned the analytical people was

to discover the relative amounts of each product present. This proved to be a formidable task, because in the gross smear of products ranging from materials with a few carbon atoms in length to those with more than 20 carbon atoms, separation and identification was most difficult. Very early work indicated that with the original crude scale wax the product was predominantly aliphatic acids. This work had been done on Titusville wax, but the new feed stock would be Cit-Con wax from the new lubricating oil and wax plant. Unfortunately all waxes are not the same, or a t least not in a wax oxidation process. For, instead of getting a preponderance of acids with our new Cit-Con wax, we were getting a preponderance of alcohols Product distribution is a real challenge to a researcher, and an investigation was undertaken to determine how product distribution could be affected. Oxidation promoters and catalysts at various temperatures were tried, and they were effective in reducing oxidation time for a given wax conversion. Oxidation time could influence the relative ratio of alcohols to acids, and by prolonging oxidation a much more favorable acid to alcohol ratio could result. T h e company was not unmindful that increasing oxidation time increased reactor size, which also increased investment cost. I t was also found that the amount of hydroxy acids formed was increased, and this was undesirable from a grease-making standpoint. Temperature, air rate, air pregsure, reactor design, and a series of other variables were studied in an effort

to influence the course of oxidation and the resulting product distribution. O n a once-through basis, more acids than alcohols could be made only by producing far more hydroxy acids than the process economics could stand. Hydroxy acid production could be limited only by running short-term oxidations which gave relatively high alcohol to acid ratios. This did not at first seem too great a barrier, because reoxidation of the alcohols could produce the desired acids. Yet difficulties arose as the acids produced by reoxidation were hydroxy acids, keto acids, and some as yet unidentified material, all of which were quite unsuitable for grease making, and a large proportion of the alcohols resisted further oxidation under the process conditions. During the course of these technical difficulties, other problems occurred. One of these was that the demand for crude scale wax was fast disappearing, and fully refined wax was becoming the major wax product of the Cit-Con refinery. So it was necessary to change the wax feed. Little difference was found between the product distribution obtained with fully refined wax and crude scale wax, but there was a price differential of about 2 cents a pound more for the fully refined wax. This was a considerable blow to the economics of the project, and the use of a soft wax material from Cit-Con, an oily wax containing approximately 20% oil, was attempted. The lack of success obtained was phenomenal, as soft wax produced a completely unsuitable and low 5

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yield mixture of hydroxy acids, mixed with a variety of unidentifiable compounds. Thus, the only possibility was the use of fully refined wax. As an additional blow, the meat eaters in the country started increasing the per capita consumption of pork, beef. and lamb, with the result that tallow and fats, from which fatty acids could be produced, were being produced in ever-increasing quantities. Concurrently, detergents started crowding out soap for laundry usage. Early in 1953 it was concluded from a fatty acid survey, that former shortages of fatty acids \vere turning into an unending surplus. The outlook for the price of fatty acids suitable for grease manufacture was now closer to 10 cents a pound rather than the 15 cents estimated in 1948. Earlier, the spread between raw material and end product was 10 cents a pound; now it was 3 cents a pound, which \vas wholly uneconomical. Changing the Product

Researchers. however, are a flexible lot, having ingenuity and creativity. At this point in time there were two problems associated \vith the process, they concluded. One was the production of alcohols which could not be used in grease making, and the second was the low price of fatty acids. Why not, they said, aim the process for the production of fatty alcohols which could be made in good yield and which showed a superior market price. Preliminary investigation of the then current price of long chain fatty alcohols did indeed show that a good average figure might be 23 cents a pound. Using this figure the process looked even rosier than it had with fatty acids along

as the objective. There were some problems associated with this change in view. but it was decided to attack them one at a time. Having been let down concerning the fatty acid future, the company decided to be much more conservative in estimating the future of fatty alcohols. Not too much was known about the utilization of these materials, nor what might happen to the price if a large new supply of these alcohols might become available; it was decided to seek assistance in determining these factors. A consultant with considerable experience in this area !vas engaged and the problem placed before him. The questions were:

What is the extent of the present and potential future market demands of wax alcohols? What prices can they be sold for? What other information can be developed which will help forecast possible markets for these mat erials? In a market study of this type there are a large number of potential users who cannot give a suitable answer until they have had a sample of the material to evaluate. The consultant, after contacting some two dozen companies, requested a large number of alcohol samples which bench scale techniques would be unable to produce in a reasonable period of time. It was necessary to build a small pilot plant for production of these samples. Much more was learned about the process during the pilot plant work, including the fact that a hydrogenation step would almost certainly be necessary for the final alcohol purification. The

New Orleans domestic prices for white crude scale wax. price for year

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Average high-low

original plant estimate had almost doubled, based upon the difficulty found in separating alcohols and acids from unreacted wax and in the numerous process steps required for purification which had not been initially foreseen. Of the two dozen firms who received samples, only three requested additional quantities. LVhen the voting was all in, the overwhelming opinion of the electorate was that these wax alcohols held no interest for any of the prospective users. The project was dropped forthwith, after four years of research and an expenditure of some considerable size. Reasons for Failure

There should be a moral here from which guidance for future research work could be obtained. What afflicted the project was that nature did not live up to expectations and the estimate of the fatty acid market was optimistic. Could the error in entering the project have been avoided? Upon further consideration, there appears to he a foolproof formula for not embarking on disappointing research projects: Don’t do anything! For if you don’t Try, you can’t fail. Failure was due to an optimistic estimate of the fatty acid market and the perversity of nature. How often d o market estimates go wrong? Evidenrly very often, as marketers of new automobiles, tooth paste, cigarettes, and other products can testify. There is no such thing as a foolproof market estimate, because one can never take into account the myriad circumstances caused by as yet unborn technology. unrealized needs, and desires or the habits of a fickle public. One can only use the best knolvledge at hand and the best judgment available and make a decision on this basis. This means that ever>-market estimate has a reasonable chance of being in error. In the case of this market survey, it was done in the best manner and as rhoroughly as the company knew hoxv. Even today it is uncertain whether a more accurate survey could be made, for predictions of the future are no more sanguine now than rhey \\.ere 10 years ago. Concerning the perversity of nature, were it not for this researchers would really have no livelihood. Sature yields her secrets reluctantly, and often cannot be coaxed into folloiving the parhs set by mortals. The moral is this: There is always a chance in undertaking a research project on the new and unknown. A company must try to limit the odds as best it can; yet there will always be a chance for failure. T o succeed, pick only safe ventures which will provide only very conservative returns. The return received will be proportionate to the risk taken. Always remember that without the existence of failure success cannot be defined.