Direct Aldolization of Unprotected Fructose to Bio-Based Surfactants

Abstract

A new alkylation mode of fructose was developed by direct aldolization of unprotected fructose with fatty aldehydes as alkylating agents. The reaction occurs in the presence of a base in a mixture of water/EtOH at 60°C under microwave irradiation.Trimethylamine was found the most effective base for the aldolization of fructose with short chain aldehydes (C4-C8) while better results were obtained with K 2 CO 3 in association with tetrabutylphosphonium bromide (TBPB) for long chain aldehydes (C8-C12). The corresponding alkylated fructose were obtained as mixture of 3 main tautomers (the -pyranoid form being the predominant isomer) and were isolated with 31-46% yield. These aldolization products were also reduced under hydrogen to give the corresponding alkylated heptaols with 84-96% isolated yields.

Eco-friendly synthesis of cardanol-based AB monomer for formaldehyde-free phenolic thermosets

“…Indeed, heptanal is a molecule of interest that is used in the perfume industry either as such or as a starting material for the preparation of jasminaldehyde. [29][30][31] Moreover, it can also be used as an alkylating agent for the aldolization 32,33 or reductive etherication of polyols [34][35][36][37] and sugars [38][39][40][41] to give biobased surfactants. Based on the results presented in Table 2, the method using NaIO 4 (route b1) appears to be the best compromise between performances (yield = 42%; AE of 43%; E factor of 8) and safety (SC of NaIO 4 = 15), provided the solvents are recycled.…”

The synthesis of fructose-based surfactants

“…The yields were around 30%. 27 A different approach to prepare fructose-based surfactants has been reported by Lemaire et al 28 In their synthesis, the aldol-condensation of fructose with long chain aldehydes was performed. This method requires 20 eq.…”