Preparation Of Tartaric Acid - Based Polyamide And Its Research On Chiral Separation

Tartaric acid-based polyamides are a type of synthetic optically active polymers,which are new and environmental-friendly.It has both the chirality of tartaric acid and molecular structure characteristics of polyamide.This makes it extremely potential for applications in the areas of chiral recognition and resolution,chiral liquid crystals,catalysts,biomedicine and sensing.Therefore,it is of great theoretical and practical significance to research and develop such tartaric acid-based polyamides with rich chiral origin,simple preparation process,and relatively low cost.The related research and results of this topic are as follows:1.A series of optically active polyamides PAnLAT and PAnDAT(n=9,10,11,12,13)were prepared by interfacial polycondensation of long carbon chain diamines with natural chiral compounds D-tartaric acid and L-tartaric acid as the raw materials.The relevant test results show that: The change of the left-and-right spin configuration of chiral monomers does not affect the preparation process of the series of polyamides and the formation of characteristic functional groups;Varying the number of methylene groups in the diamine structural unit can have a significant effect on the crystallization performance of the corresponding polyamide.The optical activity test results for the series of polyamides shows that: Tartaric acid monomer and the corresponding polyamide have positive and negative opposite specific optical rotation;The optical activity of the series of polyamides shows a certain degree of parity,the specific rotation of PA10LAT/PA10 DAT,PA12LAT/PA12 DAT is greater than that of PA9LAT/PA9 DAT,PA11LAT/PA11 DAT,PA13LAT/PA13DAT;Compared with the solution state,the solid-state series polyamide has a stronger optical activity.2.Using thin layer chromatography,a series of investigations were conducted and we found that when the ratio of the developer composition n-hexane and isopropanol(trifluoroacetic acid and water as a polar modifier)was 7:3,The PA11 LAT exhibits chiral recognition ability to the chiral compound of warfarin.Tofurther verify the polymer’s chiral recognition and resolution performance,a simple chiral column was used,which is also called solid phase extraction column.The relevant test results show that,when the column volume is 10 m L,it is more appropriate to control the polymer loading at 800 mg.In addition,the PA11 LAT and PA10 LAT columns elute D-alanine firstly,it shows that the polymer filler has stronger binding to L-alanine during elution.Compared with pure D-alanine solution and pure L-alanine solution,the strong CD absorption peaks appear at 211 nm and218 nm and the CD absorption peak of the eluent is still between 200 nm and 240 nm,but there also has a certain offset,it shows that the three-dimensional structure of the compound changes to a certain extent during the elution process.In addition,due to the low concentration of isomers in the eluent,the intensity of the corresponding CD signal is weakened.The eluent was subjected to a high performance liquid phase test and the results further confirmed the above conclusion.3.Comprehensive research and analysis found that,a series of chiral polyamides exhibit chiral resolving power for several chiral compounds without-OH,and when the compounds contain larger amino groups or groups larger the resolution effect is more pronounced.It shows that when there are multiple acting forces in the split system for synergy,the chiral separation effect is more significant.This is consistent with the interaction mechanism of the chiral chromatographic column proposed by Irving Wainer during chiral recognition resolution.The above research results show that,the series of polyamides that are prepared have great potential for application in the fields of chiral recognition and resolution.