Synthesis And Application Of Polyglycerol Ester Of Gemini Stearic Acid

A nonionic gemini surfactant is a kind of new surfactant. It has a lot of special physical and chemical properties because of dimeric structure. It has wide application in many fields and it's applied research is paied attention by more and more people. In this paper, polyglycerol ester of gemini stearic acid was synthesized by using glycerol, stearate, ethanol absolute, ethyl formate, 1,2-dibromoethane and soduim metal as starting materials through polymerization, esterification, claisen condensation, ketoester alkylation, basic cracking and substitution reaction. It's properties were also studied.A series of polyglycerol ester with different degrees of polymerization were synthesized. from glycerin through polymerization reaction. The intermediate-gemini ethyl ester stearic acid was synthesized by using stearate, ethanol absolute, ethyl formate, 1,2-dibromoethane and soduim metal as starting materials through esterification, claisen condensation, ketoester alkylation, basic cracking reaction. Then, the intermediate is separated and purified, it was characterized by IR spectrum and 1HNMR spectrum, and proved to be the intermediate as originally expected. A series of nonionic gemini surfactants (PGGE) were synthesized by transesterification the intermediate with the polyglycerol.It's surface properties were tested, and compared with the corresponding polyglycerol mono-stearate. The results showed that the surface tension of the gemini surfactant were apparently lower and the critical micelle concentration were an order of magnitude lower; emulsifying time increased by one time; the wetting time were about 39%~58% lower; and soap dispersancy were about 47%~59% lower. It indicated that the nonionic gemini surfactant has higher surface activity.And also, the polyglycerol ester of gemini stearic acid synthesized were applied on agricultural plastic film as the antifogging aggent, the antifogging property of the sprayed films was tested and compared with that of corresponding polyglycerol mono-stearate. The relationship between the polyglycerol polymerization degree and the antifogging property was investigated, and the reproducibility of films sprayed several times was discussed. Results showed that it's antifogging property is better than that of polyglycerol mono-stearate, and the films sprayed several times can be used multiple times. The antifogging property of polyglycerol ester of gemini stearic acid was better when the polymerization degree was about two, so, it is a very exllent anti-droplet aggent.