Hydrothermal synthesis of crystalline Aluminium(III)-Tartrate: effect of tartrate type and molar ratio

Aluminium(III)-tartrate (Al-T) complex is a compound that commonly used as mordent in textile dyeing. This complex is soluble in hot water; thus, information on the isolation of crystallised Al-T is limited. Isolation of crystallised Al-T is needed to gain a high purity complex for further application in the textile industry. This study aims to synthesize and isolate crystalline complex of Al-T. Hydrothermal method was used to obtain the targeted complex. Effects of tartrate precursor and Al(III):tartrate mol ratio in the synthesis of Al-T complex were also investigated. The synthesis was done at 150 °C for 24 hours in several Al(III):tartrate mol ratios (1:2, 2:1, and 2:3) using two different tartrate precursors, namely L-tartaric acid and KNa-tartrate. The synthesized complexes were identified by infrared spectroscopy and powder-XRD analyses, and then further characterised by UV Vis - DRS, DTA-TGA, and SEM. Experimental data shows that the mol ratio affects the precipitation of the Al-T complex, in which a white crystalline solid was only precipitated out from the 2:1 reaction by both tartrate precursors. Different tartrate precursors used in the synthesis may alter the crystallization and result in an Al-T complex with slightly different thermal decomposition profile, UV-Vis DRS spectra profile, and different yield due to the different nature of the tartrate precursor. This finding is expected to support the possibility of Al-T mass production as mordent in textile dyeing