The acid-catalyzed reaction of glycerol with aqueous formaldehyde was studied using various heterogeneous catalysts for the production of glycerol formal. Owing to the high amount of water involved in the reaction medium, three types of water-tolerant heterogeneous catalysts namely acid functionalized periodic mesoporous organosilicas (PMOs), zeolite ZSM-5 and a heteropoly compound Cs2.5H0.5PW12O40 as well as commercial catalyst Amberlyst-15 were used for glycerol acetalization. The activity of Cs2.5H0.5PW12O40 was found superior to that of the other catalysts and the glycerol conversion was over 70% within 60 min of reaction time. The effects of different parameters including temperature, feed,composition and catalyst content, were studied as well. The distribution of the two glycerol formal isomers could be controlled by changing reaction parameters. Optimum reactive parameters were studied to control the distribution of the acetal isomers aiming to reach a high selectivity to the six-member ring isomer. (C) 2015 Elsevier B.V. All rights reserved.