Study Of Cleavable Linear Polyoxyalkylene Acetal

Linear polyoxyalkylene acetal is a type of easily cleavable surfactants. Because of containing acetal group in the surfactants, it can hydrolyzed to aldehyde and polyoxyalkylene ether in acid condition. But in alkaline conditions even at very high PH value,it is stable. In this text, the synthesis of diethylene glycol monobutyl formal from diethylene glycol monobutyl ether and polyformaldehyde was thoroughly studied, and obtained the optimum process condition. Then, on'the basis of it, a series of linear polyoxyethylene acetal were synthesized . And the influence of the structure on the synthesis and charicteristic was showed.Industrial polyoxyethylene ether is a mixture of unreacted alchohol, polyethylene glycol and a series of polyoxyethylene ether containing different EO adduct number. Using the method of reduced pressure fractionntion, the monocomponent of polyoxyethylene ether containing two EO adduct number was obtained. Testing its hydroxyl value, analyzing the IR and 'HNMR, the structure was confirmed. In according with the reaction mechanism of alchohol and aldehyde, the reactional condition of 414 was originally explored. On the basis of it, we chose four factor which affect the productivity biggerly -change ratio, reflux way, catalyst species and catalyst weight, to conduct orthogonal experiments. The experiments were designed in according to L9(34) orthogonal table. Compared the influence different factors on productivity, and the optimum process condition was getted.Based on the optimum process condition, a series of surfactants such as diethylene glycol monobutyl, n-octyl, n-dodecyl formal and diethylene glycol n-octyl ether butyl aldehyde acetal, n-octyl aldehyde acetal, lauric aldehyde acetal were synthesized. The highest productivity can reach to 84%,which is higher than the documents' 50-80%. The polyoxyethylene ether and aldehyde which contain different alkyl group(2R1 and R) influencing the reaction and surface activity were compared. The result indicated that the clouding point descended and CMC reduced as the number of carbon in alkyl group raised. Different from the documents, when R1>C8H17, it have surface activity, and CMC is present. And 414 hydrolysis property was studied. The consequence showed that hydrolytic rate constent ascends with the PH value reduced and temperature raised.In this article all the product were analyzed with IR and 1HNMR spectra, and determined their structure. In IR spectra, hydroxyl bands didn't exist. And 1HNMR spectra acetal group is 4.75ppm.