3,4,5-Tri-dodecyloxybenzoic acid: Optimisation and scale-up of the synthesis

The synthesis of tris-O-dodecyl-gallic acid (3,4,5-tri-dodecyl-oxybenzoic a cid-a versatile building block for organic liquid crystalline materials-has been selected for fine chemical scaleup. A large-scale procedure of the al kylation of methyl gallate was optimised with experimental design technique s. Apart from the solvent effect, also the temperature, phase-transfer cata lyst, stirring speed, and amount of base were found to be most significant for the reaction rate. Reaction calorimetry revealed no excessive exothermi c reaction steps in the process. Reaction kinetics on the alkylation reacti on was studied as a function of particle size distribution of the base, pot assium carbonate, and formation of cai bon dioxide, Combination of all expe rimental results has debouched into a master recipe for kilogram-scale synt hesis in a 10 dm(3) fully automated (semi)batchwise operated reactor.