A principal challenge in using biomass as a replacement for petroleum has been to develop cost-competitive and sustainable processing technology. Cellulose in biomass can be converted into levulinic and formic acids through acid catalyzed hydrolysis and dehydration, conventionally done using sulfuric acid. These products can be used as chemical feedstocks or converted to advanced biofuels. Product separation and sulfuric acid recovery are significant hurdles hindering the commercialization of the acid-catalyzed process. Hydrolysis of cellulose using a-hydroxysulfonic acids (alpha HSAs) presents a novel approach to simplifying acid recovery from biomass hydrolysates. We present the results of comparing six different alpha HSAs, including two derived from molecules produced by the hydrolysis itself, for conversion of glucose or cellulose to levulinic acid. After evaluating the six compounds for qualities of catalytic activity, thermal stability, and recyclability, we found that acetone-derived alpha HSA compares favorably in terms of these metrics. Highest yields of levulinic acid derived from cellulose were 40% of theoretical, achieved at conditions of 150 degrees C, 24 h reaction time, 3% cellulose feed, and 1.875 M acetone-derived alpha HSA.