Answer to Question #58278 in Physical Chemistry for sabariswaran
Why Di propylene glycol's color changes from colorless into yellowish in storage tank without any disturbance? How will it happens? Please help me and also attach some articles which may help me as soon as possible!
Answer: Dipropylene glycol is a mixture of three isomeric chemical compounds, 4-oxa-2,6-heptandiol, 2-(2-hydroxy-propoxy)-propan-1-ol, and 2-(2-hydroxy-1-methyl-ethoxy)-propan-1-ol. It should be stored in cool, dry place in tightly sealed containers, protected from heat and light. Its shelf life 24.00 month(s) or longer if stored properly. In the same way as most organic compounds dipropylene glycol undergoes decomposition with time. Its degradation occurs even easier because dipropylene glycol is not an individual compound but a mixture of compounds. Light and heat increase destructive processes. Oxygen and water vapor from air cause oxidation in dipropylene glycol. Containers where dipropylene glycol is stored always contain some air and water vapor. As the result of decomposition and oxidation of dipropylene glycol impurities accumulate and then they react further with dipropylene glycol. Formed compounds are of complex structure and usually they have yellowish color.