1,4-Dihydroxy-2,2,6,6-tetramethylpiperidine → biphenyl diacrylate 2,2'-Diethoxybiphenyl diacrylate

Participants

Reaction Conditions

Reaction Steps

To a 12000 ml 4 neck resin head round bottom equipped with a temperature probe, nitrogen purge tube, an overhead stirrer and heating mantel was added 2,2′-biphenol (1415 g, 7.6 moles, 1.0 equivalents), potassium fluoride (11.8 g, 0.2 moles, 0.027 equivalents), ethylene carbonate (1415 g, 16.1 moles, 2.11 equivalents) and heated to 155° C. At 4.5 hours, GC analysis indicated 0% starting material, 0% monoethoxylated and 94% product. Cooled to 80° C., added toluene 5.4 liters, added 2.5 liters deionized water, mixed for 15 min and phase separated. Removed the water and washed again with 2.5 liters deionized water, phase separated, removed the water and distilled solution to remove residual water and approximately 1.8 liters of toluene. The solution was cooled to 50° C. and added cyclohexane 1.8 liters, 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy obtained from CIBA Specialty Chemicals under the trade designation Prostab 5198, commonly referred to a 4-hydroxy TEMPO (0.52 g, 0.003 moles, 0.00044 equivalents), phenothiazine (0.52 g, 0.0026 moles, 0.00038 equivalents), acrylic acid (1089.4 g, 15.12 moles, 2.2 equivalents), methane sulfonic acid (36.3 g, 0.38 moles, 0.055 equivalents) and heated to reflux (pot temp was 92-95 C). The flask was equipped with a dean stark trap to collect water. After 18 hours GC analysis indicated 8% monoacrylate intermediate. Added an additional 8 g acrylic acid and continued refluxing for another 6 hours for a total of 24 hours. After 24 hours GC analysis indicated 3% monoacrylate intermediate. The reaction was cooled to 50° C. and treated with 2356 ml 7% sodium carbonate, stirred for 30 min, phase separated, removed aqueous, washed again with 2356 ml DI water, phase separated and removed aqueous. To the (pink-red) toluene/cyclohexane solution was added 4-hydroxy TEMPO (0.52 g, 0.003 moles, 0.00044 equivalents), phenothiazine (0.52 g, 0.0026 moles, 0.00038 equivalents), aluminum n-nitrosophenylhydroxylamine (0.52 g, 0.0012 moles, 0.00017 equivalents) and concentrated with vacuum to approximately 5000 ml solution. Filtered through a pad of celite and the filtrate was concentrated with vacuum with an air purge, at 50° C. and 12 torr vacuum for 3 hours. The resulting yellow to brown oil is further purified by distilling on a roll film evaporator. The conditions for distillation were heating the barrel at 155° C., condenser at 50° C. and 1-5 mtorr. The recovered yield was 2467 g (85% of theoretical) and purity was approximately 90% DEBPDA.

Provenance & Evidence