Silica M41S type materials have been prepared starting from the mixture: 0.29 Na2O:0.12 CTABr:1 SiO2:100 H2O using water–glass as silica source. Syntheses were carried out at three different temperatures: 303, 343 and 413 K. The effect of the synthesis temperature on the nature of the products, the presence of Al, Fe or Zn, as well as the properties of the so-obtained materials and their thermal stability were studied. XRD, N2 adsorption, FTIR and NMR techniques were used for the characterization of the products. The adopted procedure enables the synthesis of thermally stable hexagonal mesoporous materials from hydrogels with Si/Al ratios ⩾10. The Al forms contain both Brønsted and Lewis acid sites, whereas the Fe forms only contain Lewis acidic sites.