Synthesis and characterization of new layered silicates in the system SiO2–NaOH–tetramethylammonium hydroxide–1,4-dioxane

Novel layered silicates (denoted as α-HLS, α-HLS-AN1, γ-HLS) have been synthesized by hydrothermal treatment from SiO2, tetramethylammonium hydroxide, NaOH, and 1,4-dioxane. The effect of the NaOH concentration and reaction time was investigated. With increasing the concentration of NaOH, the obtained silicate was changed from α-HLS to β-HLS, which was previously reported as HLS (helix layered silicate). X-ray diffraction patterns of α- and β-HLS were very close to each other but there was some differences in their structure and in the temperature stability.