The Production of Rubber from Furfural

Abstract

Abstract The preparation of piperylene, or 1,3-pentadiene, from furfural has been undertaken with the view of developing a commercially practical process. Although other paths are possible, the following three steps were considered the most direct and feasible. During the course of this study, a patent was granted which covered essentially the same process, but the claims, particularly of the last two steps, were not substantiated in this laboratory. Vapor-phase catalytic reactions were utilized in the process. For the first two steps, a vapor phase hydrogenation apparatus with a recirculation device, was employed. This effected the saving of considerable quantities of hydrogen and uncondensed materials. The apparatus could also be employed for the dehydration in the last step. More than twenty catalysts were studied for the conversion of furfural to methylfuran (sylvan). Only two types were found to be satisfactory. The copper deposited from the decomposition of copper acetate on a carrier such as activated charcoal was found to give yields of the order of 80–85 per cent consistently with one passage of the furfural over the catalyst. The best catalyst tried, however, was copper chromite dispersed on activated charcoal. This has been observed to give a yield of 95 per cent of sylvan in one passage. The optimum temperature observed for these catalysts was around 200° C. It is interesting to note that copper chromite in the liquid phase produces furfuryl alcohol (or tetrahydrofurfuryl alcohol according to the conditions used) in quantitative amounts.