ALKYLATION OF ISOBUTANE WITH C-3-C-4 OLEFINS - IDENTIFICATION AND CHEMISTRY OF HEAVY-END PRODUCTION

The chemistry of the production of C-10-C-16 isoparaffins during the a lkylation of isobutane has been significantly clarified based on the n ew analytical information obtained in this investigation. These heavy isoparaffins are produced when isobutane is alkylated with C-3-C-4 ole fins using either sulfuric acid or HF as the catalyst: at least 14 fam ilies of isomers are present in this heavy-end fraction, and many C-10 -C-12 isoparaffins present in larger quantities have now been identifi ed. This new information also permits better evaluation of process con ditions for alkylation and improved calculation of yields. Since 10-16 wt % of industrial alkylates often are C-10-C-16 isoparaffins, these heavier isoparaffins often have a significant effect on alkylate quali ty (or octane number) when they are left in motor fuels. To obtain thi s new analytical evidence, seven alkylates produced using different ol efins and/or different acid catalysts were analyzed using a gas chroma tographic unit, and the results were compared. In addition, mass spect rometric results and the normal boiling points of C-10-C-12 isoparaffi ns were employed.