Investigating the Impact of Water and Methanol on Deep Eutectic Solvents by Raman Spectroscopy and Principal Component Analysis
Abstract (300 words maximum)
Deep eutectic solvents (DESs) are promising versatile and sustainable green solvents alternatives to conventional organic solvents. DESs are two component-based solvents formed by molecular and ionic compounds acting as hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs). They are typically mixed at a specific molar ratio to form the optimum number of non-covalent interactions among the constituents. However, high viscosity limits the application of these solvents. In this study, we have synthesized menthol-thymol (Men:Thy) and choline chloride: ethylene glycol (ChCl:Eg) DESs and explore the impact of water and methanol on these DESs. The formation of the DES was confirmed by FTIR and Raman experiments. Various amounts of water and methanol from 1% to 50% were added to the two DES systems to investigate the impact of the water and methanol content on the DES systems. Raman spectroscopy and principal component analysis (PCA) results showed that 1-5 % of water and methanol do not disrupt the Raman shift significantly for ChCl:EG DES. However, significant change is noticed while 10-50 % water and methanol were added to the ChCl:EG DES system. Nearly similar trend was observed for Men:Thy DES system. Addition of 1% percent of water has no impact on the Men:Thy DES, however, adding up 5-50% water demonstrates a noticeable impact on DES and making them clustered together in the PCA. However, methanol has inconsistent impact on Men: Thy DES as indicated in the PCA plot. This study revealed that the low percent of co-solvents has less influence on DESs compared to the high content.
Academic department under which the project should be listed
CSM - Chemistry and Biochemistry
Primary Investigator (PI) Name
Mohammad A. Halim
Investigating the Impact of Water and Methanol on Deep Eutectic Solvents by Raman Spectroscopy and Principal Component Analysis
Deep eutectic solvents (DESs) are promising versatile and sustainable green solvents alternatives to conventional organic solvents. DESs are two component-based solvents formed by molecular and ionic compounds acting as hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs). They are typically mixed at a specific molar ratio to form the optimum number of non-covalent interactions among the constituents. However, high viscosity limits the application of these solvents. In this study, we have synthesized menthol-thymol (Men:Thy) and choline chloride: ethylene glycol (ChCl:Eg) DESs and explore the impact of water and methanol on these DESs. The formation of the DES was confirmed by FTIR and Raman experiments. Various amounts of water and methanol from 1% to 50% were added to the two DES systems to investigate the impact of the water and methanol content on the DES systems. Raman spectroscopy and principal component analysis (PCA) results showed that 1-5 % of water and methanol do not disrupt the Raman shift significantly for ChCl:EG DES. However, significant change is noticed while 10-50 % water and methanol were added to the ChCl:EG DES system. Nearly similar trend was observed for Men:Thy DES system. Addition of 1% percent of water has no impact on the Men:Thy DES, however, adding up 5-50% water demonstrates a noticeable impact on DES and making them clustered together in the PCA. However, methanol has inconsistent impact on Men: Thy DES as indicated in the PCA plot. This study revealed that the low percent of co-solvents has less influence on DESs compared to the high content.