Abstract:

The butoxylation of dodecanol with 1, 2-epoxybutane （BO） was catalyzed by KOH, NaOH, MCT-09, CH₃ONa and CH₃OK. The reaction rates in presence of these five alkaline catalysts were compared and the reaction mechanisms and causes were described. The alkalis reacted with dodecanol to produce alkoxide anions which carried out the chain initiation reaction, and the monomers were activated to regulate the chain growth. The ring opening of BO took place at the epoxide carbon of less steric hindrance, and thus the anionic ring-opening polymerization proceeded. Analysis of reaction rate showed that, among these alkalis, NaOH with a larger molar concentration catalyzed the system the fastest, however, exhibiting the broadest distribution of products. The catalytic rates of CH₃ONa and CH₃OK were slower because the catalysts were dissolved in methanol. MCT-09 had the slowest catalytic rate due to its weak alkalinity, but its product distribution was the narrowest. The structure of polyoxybutylene lauryl ethers synthesized with different catalysts was determined by FT-IR, GC-MS, ¹H-NMR and ¹³C-NMR, and their self-assembly behavior, physicochemical and application properties were also investigated. The results showed that the self-assemblies around 200 nm could be observed under both TEM and SEM, in which the formation of aggregates was ascribed to the hydrophobic interaction and hydrogen bonding between the BO chain and water. The physicochemical and application properties of those five products were tested, and it was found that the products with a broader distribution had better performance, while the products with relatively narrower distribution had worse performance. Therefore, the BO distribution was the main factor influencing the properties of products synthesized with different catalysts.

Key words: 1, 2-epoxybutane, butoxylation, self-assembly behavior, application property