Heterogeneous catalysis for the ketalisation of ethyl levulinate with 1,2-dodecanediol: Opening the way to a new class of bio-degradable surfactants

• Ketalisation reaction between ethyl levulinate and alkyl 1,2-diols was evaluated.
• Different heterogeneous catalysts have shown good catalytic performances.
• Niobium phosphate was preferred for its easier and better recyclability.
• A surfactant was synthetised by alkaline hydrolysis of the ketal with longer chain.
• The new green bio-surfactant showing good surface tension properties.

The acid-catalysed ketalisation between ethyl levulinate and two different alkyl 1,2-diols (ethylene glycol and 1,2-dodecanediol) was investigated using different acid catalysts, e.g. p-toluensolfonic acid, Amberlyst 70, zeolite H-ZSM-5, and niobium phosphate. Good activity and recyclability were achieved in the reaction with ethylene glycol catalysed by niobium phosphate. Very promising results (both in diol conversion and in selectivity towards the desired ketal) were ascertained in the reaction with the longer-chain 1,2-dodecanediol catalysed by heterogeneous catalysts. The alkaline hydrolysis of the synthetised long-chain ketal ester allowed us to obtain a new green surfactant, with surface tension values falling in the range of the commercial anionic ones.

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