when i distilled the pyridine its color is completely transparent. I am using 4-vinyl pyridine under nitrogen flow. But after sometime it changes the color. i know its photo sensitive thats why i am cover my 4-vinyl pyridine with aluminum foil. Even sometime i don't use the 4-VP for long time and when i take it out from refrigerator its color become light brown. it just change the color , there are no particles inside, it means there is no polymerization. Should i need to distilled again this 4-VP or color changing ability don't effect the experiment????