tert-Butyl hydroperoxide → Acrylic acid hydroxyethyl methacrylate

Participants

Reaction Steps

Into a 5 liter 3-neck round bottom flask is charged 2960 ml of deionized (DI) water. The water is heated with a heating mantle to 85°-87° C. while being stirred with a mechanical stirrer. While this is being done, 416 g of acrylic acid (AA) and 104 g of 2-hydroxyethyl methacrylate (HEMA) are charged into a one-liter graduated separatory funnel. A 1 wt.% aqueous solution of ammonium persulfate (APS) is also prepared. When the temperature of the water levels off at 85°-87° C., 13 ml of the 1 wt.% APS solution is added to the reactor. The monomer solution and a co-feed catalyst of 52 ml of the 1 wt.% APS solution are then added gradually and proportionally to the reactor over a period of about two hours. During the addition the temperature is maintained at 85°-87° C. and agitation is increased gradually to maintain good stirring. After the additions are completed the polymer solution is held at 85°-87° C. for 30 minutes. At the end of the 30 minute time period an additional catalyst system consisting of 0.4 g of tertiary butyl hydroperoxide diluted in 10 ml of DI water and 0.3 g of sodium sulfoxylate formaldehyde dissolved in 10 ml of DI water are added. Stirring is continued for 30 minutes. A neutralizer consisting of 232 g of 50% sodium hydroxide is added. Stirring is continued for about 30 minutes. The product obtained is a clear solution with a viscosity of about 7000 cps (Brookfield Viscometer, 12 rpm, spindle 3, 20° C.±2° C.) and has a polymer solids content of 15.4% with about 50% of the acid groups neutralized.

Provenance & Evidence