The role of boric acid in the synthesis of Eni Carbon SilicatesElectronic supplementary information (ESI) available. See DOI: 10.1039/c4dt00919c

• Main Authors: Zanardi, Stefano, Bellussi, Giuseppe, Parker Jr, Wallace O'Neil, Montanari, Erica, Bellettato, Michela, Cruciani, Giuseppe, Carati, Angela, Guidetti, Stefania, Rizzo, Caterina, Millini, Roberto
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c4dt00919c

The influence of H 3 BO 3 on the crystallization of hybrid organic-inorganic aluminosilicates denoted as Eni Carbon Silicates (ECS's) was investigated. Syntheses were carried out at 100 °C under different experimental conditions, using bridged silsesquioxanes of general formula (EtO) 3 Si-R-Si(OEt) 3 (R = -C 6 H 4 - (BTEB), -C 10 H 6 - (BTEN) and -C 6 H 4 -C 6 H 4 - (BTEBP)), in the presence of equimolar concentrations of NaAlO 2 and H 3 BO 3 . The study, involving the synthesis of three different but structurally related phases (ECS-14 from BTEB, ECS-13 here described for the first time from BTEN, and ECS-5 from BTEBP), confirmed a catalytic role for H 3 BO 3 which in general increased the crystallization rate and improved the product quality in terms of amount of crystallized phase (crystallinity), size of the crystallites and phase purity, while it was weakly incorporated in trace amounts in the framework of ECS's. Boric acid accelerates the crystallization rate of Eni Carbon Silicates improving their crystallinity and phase purity, favoring also the formation of new structures.