Fatty methyl ester hydrogenation to fatty alcohol: Reaction inhibition by glycerine and monoglyceride

The present work demonstrates the rate-limiting effect of varying levels of both glycerine and monoglyceride through a series of batch hydrogenations of fatty dodecyl methyl ester, using copper chromite as the catalyst. React ions were carried out at 3000 psig H-2, 280 degrees C with catalyst levels varying between 1.25 and 1.80%. With increasing contaminant levels of glyce rine (0.0, 0.1, 0.5, 5 wt%), conversion of fatty methyl ester to alcohol is correspondingly reduced (95, 89, 80, 2 wt%). On a molar basis of contamina nt, monoglyceride equally reduces the conversion of methyl ester to alcohol . In both cases the latent appearance of fatty-fatty ester results from the slower hydrogenation rate. Chemistry is proposed outlining the thermal dec omposition of glycerine or glyceride to intermediate components (acetol and acrolein), leading to the generation of propanediols. Experimental studies indicate that diols effectively deactivate the copper chromite catalyst, l imiting the rate of fatty methyl ester hydrogenation. Catalyst deactivation is not permanent, suggesting catalyst site blockage by physical adsorption of the polyhydroxyl components. The complete understanding of this interac tion holds promise for the development of glycerine/monoglyceride-insensiti ve catalysts. In addition, a brief overview of methyl ester hydrogenation i nhibition effects of some heteroelements, water, and soap is presented.