The alkylation of isobutane with C4 olefins is studied, using heteropolyacids (HPA) with Wells-Dawson (WD) structure supported on silica (WD/SiO2). The catalytic performance of these catalysts is compared with a lanthanum-exchanged Y-zeolite catalyst. The loading of the HPA on silica was varied between 9 and 28 wt.%. These catalysts have activity for trimethylpentanes (TMP) production. The selectivity towards these products is not as high as in the case of the lanthanum containing Y-zeolite. The acidity of WD/SiO2 Catalysts increases as the loading increases, as seen by H-1 MAS-NMR. Correspondingly, a better TMP production is observed. The increase both in acidity and in the TMP production as a function of the WD content is more noticeable at low loading. The coke formed during the reaction requires high temperatures, 550 degreesC approximately, in order to be fully removed with an oxygen containing carrier gas. The temperature-programmed oxidation (TPO) profile of this coke displays two peaks, the first one between 80 and 300 degreesC associated with hydrocarbons that are released upon heating, and the second between 300 and 550 degreesC, associated with coke that changed its structure during the heating. A regeneration at intermediate temperatures, e.g. 300 degreesC, removes the coke that corresponds to the first peak, but does not restore the initial activity. If the regeneration is carried out at higher temperatures, e.g. 500 degreesC, most of the coke is removed, but this treatment leads to changes in the structure of the HPA, as indicated by FTIR and MAS-NMR analysis. Regeneration with O-3 at low temperature (125 degreesC) is effective both for coke removal and to recover the catalytic activity.