With the possible exception of catalytic hydrogenation, perhaps no unit operation within the realm of oleochemistry is as thoroughly complex as that of glycerolysis. Among the misconceptions and half‐truths that prevail concerning the glycerolysis of fats are the notions that it involves a strictly random distribution of acyl groups among all of the available hydroxyl groups, that the solubility of glycerol in the fat at the reaction temperature determines the yield of monoglyceride that may be obtained, that the advantageous effects of the Law of Mass Action can be realized only when the reaction media is in ultimate homogeneity, in other words, complete mutual solubility, and, more importantly, that there is an equivalence of emulsification properties for the chief products of glycerolysis, i.e., the α‐and β‐monoglycerides, in both food and industrial emulsification. Numerous examples from international literature establish the limitations which prevail in temperature, agitation and use of excess of glycerol in batch glycerolysis reactions, but the practical limits for glycerolysis undersuperemulsification conditions remain to be established. The disadvantages of glycerolysis in homogeneous solvents still are insufficient to justify the use of those that are available, but the use of both pressure and gaseous catalysts such as carbon dioxide appear to offer the greatest hope for improvement in yields. Substantial energy savings may dictate the choice of methyl ester glycerolysis processing for future plants, especially those in the international sphere. Pros and cons of monoglyceride analytical methodology are evaluated.

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Although acquisition, divestiture and other organizational changes within the American oleochemical industry are still the most startling and attention‐attracting, the development of new technology continues to be of paramount scientific interest. Noteworthy among the new developments are (a) the continuing development of new vegetable oil raw materials like 90% erucic acid rapeseed oil and 80% oleic acid sunflower; (b) the intense process development under way in some areas for the minimization of thermal energy requirements of certain reactions like polymerization (dimer acids), glycerolysis (mono‐ and diglycerides) and fat splitting; (c) the ever‐increasing substitution of methyl esters for fatty acids in the production of a whole series of oleochemicals; (d) development of new esterification catalysts; (e) lipase catalysis of interesterification; (f) development of new corrosion‐resistant materials of construction; (g) the use of irradition sulfoxylation as a preferred production route to randomly sulfonated methyl esters; and (h) superemulsification as an aid to hydrophobic/hydrophilic liquid chemical reactions. Continued attention to alternative feedstocks, biotechnology, microprocessor technology, pollution control and lower energy consumption are certain to receive considerable attention for the next several years.

Fat splitting, particularly the continuous, high pressure, countercurrent hydrolysis of fats and oils, typified by the Colgate‐Emery or modified processes, represents the technological cornerstone for today's American fatty acid industry. Internationally, other methods such as Twitchell or batch autoclave “medium‐pressure” catalyzed or uncatalyzed splitting are still important. All industrial fat splitting methods have as their objectives the attainment of a high rate of hydrolysis together with a high degree of completeness. This objective is achieved, more or less, by the proper optimum balance of: (a) use of excess water; (b) selection of appropriate combination of temperature and pressure to optimize the solubility of liquid water in the fat phases with or without use of suitable “water‐in‐oil” emulsifiers; (c) use or nonuse of acidic catalyst (rarely basic catalysts); and (d) removal of byproduct glycerol. Significant conditions and details in fat splitting by the important commercial processes are described.