The method to produce functionalized PEG was according to
Bückmann’s reference [27]. 0.01mol PEG 4000 was dissolved in
100ml toluene in the presence of 50% Et3N. 0.03 mol thionyl chloride
was added dropwise in 30 min under reflux [28]. The sample
was heated for 4 h. After evaporation in vacuo, the product PEG
chloride was obtained (Fig. 2).