In the structure of boric acid dibasic alcohol ester synthesized by boric acid, three B O bonds form a plane triangle, but the unhybridized 2p empty orbital is easy to accept the coordination bonds formed by lone pairs of oxygen atoms in intramolecular free hydroxyl groups, which induces the valence electron configuration of boron atoms to become a thermodynamically stable sp3 hybrid orbital with a regular tetrahedron structure, thus forming a semi-polar boron spirocyclic structure. The experiment shows that [3], the hydroxyl group in the molecule of boric acid glycol ester is not free, but forms a semi-polar combination with boron atom. Because these intermediates contain active hydroxyl groups, they can continue to react with different functional groups to generate different types of surfactants.
1. 1 synthesis of diglyceride borate The molar ratio of boric acid to glycerol is 1∶2. When the boric acid is slightly excessive, a proper amount of catalyst is added, and the diglyceride borate is obtained by heating reaction. The acid value of the product is controlled within the theoretical range, and a colorless transparent viscous liquid is obtained.
Synthesis of ethylene oxide adduct of 1.2 diglyceride borate in the presence of a certain catalyst, diglyceride borate is added with ethylene oxide to obtain a borate compound with a certain amount of ethylene oxide adduct at one end, and the hydrophilicity of the intermediate is greatly improved.
1.3 The molar ratio of diglyceride borate/ethylene oxide adduct of diglyceride borate and organic acid is 1: 1. When the organic acid is slightly excessive, under the action of a certain amount of catalyst, the temperature is raised to carry out esterification reaction to obtain diglyceride borate fatty acid ester. The existing industrialized dodecacarbonic acid to behenic acid can be esterified with diglyceride borate to obtain the corresponding organic boron surfactant.