Lyle F. Albright

Quantitative measure of selectivity of hydrogenation of triglycerides

Graphs have been prepared using a digital computer that allow the quantitative determination of the degree of selectivity for the hydrogenation of cottonseed, peanut, corn, soybean and linseed oils. Use of these graphs requires only a knowledge of the composition of the initial (unhydrogenated) oil and that of the hydrogenated oil plus simple calculations. If the exact composition of the initial oil is unknown, a typical composition can generally be assumed.

Selectivity and isomerization during partial hydrogenation of cottonseed oil and methyl oleate: Effect of operating variables

Results are now available for hydrogenation of cottonseed oil and methyl oleate in which sufficient agitation was provided to eliminate mass transfer resistances from the catalyst surface. The ratio of thetrans-to-cis isomers of oleic acid groups approaches 2.0 even at high pressures and high degrees of agitation. The rates of hydrogenation for bothcis andtrans isomers and for positional isomers are all essentially identical. A reaction scheme has been devised that is consistent with extensive experimental data, and the method of evaluating the relative reaction rate constants for each step is outlined. Using these rates constants, selectivity can be quantitatively evaluated.

Albright's Chemical Engineering Handbook

Physical and Chemical Properties A.H. Harvey Mathematics in Chemical Engineering D. Ramkrishna and S.H. Tringh Engineering Statistics D.W. Siderius Thermodynamics of Fluid Phase and Chemical Equilibria K.C. Chao, D.S. Corti, and R.G. Mallinson Fluid Flow R. Darby Heat Transfer K.J. Bell Radiation Heat Transfer Z.M. Zhang and D.P. DeWitt Mass Transfer J.R. Fair Industrial Mixing Technology D.E. Leng, S.S. Katti, and V. Atiemo-Obeng Liquid-Liquid Extraction D.W. Tedder Chemical Reaction Engineering J.B. Joshi and L.K. Doraiswamy Distillation J.R. Fair Absorption and Stripping J.R. Fair Adsorption K.S. Knaebel Process Control J.B. Riggs and W. Korchenski Conceptual Process Design, Process Improvement, and Trouble Shooting D.R. Woods and A.N. Hrymak Chemical Process Safety R.W. Prugh Environmental Engineering: A Review of Issues, Regulations, and Resources B.P. Carpenter, D.E. Watson, and B.C. Carpenter Biochemical Engineering J.M. Lee Measuring Physical Properties L.F. Albright Selecting Materials of Construction (Steels and Other Metals) D.A. Hansen Solid/Liquid Separation F.M. Tiller, W. Li, and W. Chen Drying: Principles and Practice A.S. Mujumdar Dry Screening of Granular and Powder Materials A.J. DeCenso and N. McCauley Conveying of Bulk Solids F. Thomson Principles and Applications of Electrochemical Engineering P.N. Pintauro Patents and Intellectual Property M.H. Heines Communication F.S. Oreovicz Ethical Concerns of Engineers L.F. Albright

Coke deposition from acetylene, butadiene and benzene decompositions at 500–900°C on solid surfaces

Abstract Coke formation from decomposition of acetylene, butadiene, and benzene and decoking were investigated on Incoloy 800, aluminized Incoloy 800, and Vycor glass surfaces at 500–900°C. On Incoloy 800, the coke was greater in quantity and contained iron and nickel particles. On aluminized Incoloy 800, the coke contained a trace of aluminum, but on Vycor glass, no metal was in the coke. Coking-decoking sequences were highly corrosive on Incoloy 800 surfaces, but they had much less effect on the aluminized Incoloy 800 or Vycor glass. Filamenteous coke which is formed catalytically and contains nickel and iron was formed only on Incoloy 800 surfaces. A general mechanism for formation and deposition of coke is proposed. Filamenteous coke helps collect tar droplets formed by gas-phase reactions. Such droplets decompose on the surface to produce coke that contains no metal.

Mechanism of hydrogenation of triglycerides

Factors affecting the rate of hydrogenation, selectivity, and isomerization are discussed in detail. The proposed mechanism for the reaction involves transfer steps for the reactants and products to and from the catalyst surface and the chemical steps occurring on the catalyst surface.

Quantitative measure of geometrical isomerization during the partial hydrogenation of triglyceride oils

A mathematical model has been developed using a digital computer for the calculation of the isomerization index for partially hydrogenated oils such as cottonseed, soybean, peanut or corn oil. The isomerization index is defined as the ratio of the rate of geometrical isomerization of an unsaturated group to the rate of hydrogenation. Isomerization indices from about 0.3 to 11 were found to occur for hydrogenations using commercial nickel catalysts. Calculation of both an isomerization index and a selectivity ratio will be useful methods of quantitatively characterizing the partial hydrogenation of triglyceride oils or the type of hydrogenation which can be obtained by various catalysts.

Solvent hydrogenation of cottonseed oil

Refined and bleached cottonseed oil was dissolved in a solvent (hexane, isopropyl alcohol, or di-isopropyl ether) and was then hydrogenated in a dead-end hydrogenator. Hydrogenation runs were conducted at temperatures from 115 to 145°C., at hydrogen partial pressures from 44 to 74 p.s.i.a., with catalyst concentrations varying from 0.05 to 0.40% nickel, and at high rates of agitation to climinate mass-transfer resistances. A series of hydrogenation runs was also made in which no solvent was used.The rates of hydrogenation for the various series of runs were in the same order of magnitude but decreased in the following order: nonsolvent, hexane, isopropyl alcohol, and di-isopropyl other runs. Selectivity and isomerization were low in all cases and essentially identical for solvent and nonsolvent runs.The rate of hydrogenation increased in all cases with higher catalyst concentrations. For the isopropanol runs, the reaction rate was maximum as a function of temperature at about 135°C. In the case of the other solvents, the rate of hydrogenation increased with increased temperature in the range from 115 to 145°C., but the rate increases of the solvent runs were less than those of the nonsolvent runs.

Transfer and adsorption steps affecting partial hydrogenation of triglyceride oils

The numerous transfer, adsorption and true hydrogenation steps which occur during the partial hydrogenation of triglyceride oils are reviewed and discussed. Transfer steps involve the transfer or diffusion of the reactants to the catalyst surface and possibly also into the pores of the catalyst. In addition, the reaction products must then also be transferred back to the main body of the triglyceride oil. Such reaction products include not only the saturated groups (formed by the hydrogenation of the unsaturated groups) but also the geometrical and positional isomers of the original unsaturated groups. Once an unsaturated group reaches the catalyst surface, it is generally assumed that it is adsorbed on the catalyst. Polyunsaturated fatty groups are however preferentially adsorbed relative to monounsaturated fatty groups. The overall kinetics of hydrogenation affects the relative ratio of the adsorption of the polyunsaturated to the monounsaturated groups at the catalyst surface. Transfer and adsorption steps frequently, if not always, are the critical steps in controlling the degree of isomerization and selectivity of reactions in the partial hydrogenation process. Additional information is still needed relative to these steps but the general trends which occur are discussed.

Catalyst studies for hydrogenation of vegetable oils

Cottonseed and soybean oils were partially hydrogenated using various commercial nickel catalysts. Methods were investigated by which commercial catalysts can be changed with respect to the rate of reaction, selectivity ortrans-isomerization during hydrogenation of the oils. Catalysts which were treated with hydrogen sulfide produce considerably moretrans isomers but catalysts treated with air often cause higher selectivity ratios. Factors affecting the hydrogenation characteristics of a catalyst are discussed.

Application of partial hydrogenation theory to the design of commercial reactors for hydrogenating triglyceride oils

Within the last 15–20 years, major advances have been publicized regarding the mechanism and general understanding of the partial hydrogenation of triglycerides, including soybean oil, cottonseed oil, corn oil and various animal fats (primarily hog and beef fats). Although edible shortenings, oleomargarine stocks and soap stocks are produced in large quantities, there is considerable doubt that the theory and fundamental information relative to hydrogenation is always applied to the fullest extent in designing and operating commercial reactors. This paper will review past accomplishments, the current state of the art and probable directions to be taken to obtain even further reactor improvements.