Study On Synthetic Process And Its Improvement Of Antioxidant 2246

2246(2,2-Methylenebis(4-methyl-6-tertiary butyl phenol))is a very valuable hindered phenol antioxidant, with lower toxicity, less environmental pollution, better thermal stability, and it is widely used in natural rubber, synthetic rubber, latex, and many other synthetic materials, petroleum products. The main research on my paper is concentrated on the synthesis of 2246. During the process we tried many kinds of solid catalysts such as ion exchange resins catalysts DNW-1, TS-92, molecular sieve catalysts HRSY-1, RDSY, REY, solid super acid SO₄^2-/TiO₂.One way is using 2-tertiary butyl-4-methylphenol and methylal as raw materials, with different ways of removing water from the methylal. After changing the conditions of the reaction like catalyst amount, reaction time, temperature, the ratio of raw materials, we confirmed how those conditions worked on the yield and purity of 2246.When DNW-1 was chosen as the catalyst, the better reaction conditions of using methylal without water removal were as follows: 2-tertiary butyl-4-methylphenol 20.5g, DNW-1 15g, methylal 80mL, reaction temperature 49-51℃, reaction time 8h, the yield (corresponding purity) of 2246 was61.8%(97.8%), and the melting point was 125-128℃. The better reaction conditions of using methylal treated with CaCl2 for 1 day were as follows: 2-tertiary butyl-4-methylphenol 20.5g, DNW-1 15g, methylal 80mL, reaction temperature 49-51℃, reaction time 8h, the yield (corresponding purity) of 2246 was 92.8%(94.9%), and the melting point was 118-122℃. The better reaction conditions of using methylal treated with CaCl2 for 3 days were as follows: 2-tertiary butyl-4-methylphenol 20.5g, DNW-1 15g, methylal 80mL, reaction temperature 44-46℃, reaction time 10h, the yield (corresponding purity) of 2246 was 96.5%(96.9%), and the melting point was 117-121℃. When TS-92 was chosen as the catalyst, the better reaction conditions of using methylal treated with CaCl2 for 3 days were as follows: 2-tertiary butyl-4-methylphenol 20.5g, TS-92 12g, methylal 80mL, reaction temperature 54-56℃, reaction time 8h, the yield (corresponding purity) of 2246 was 94.5%(94.2%), and the melting point was 122-126℃. When molecular sieve catalysts HRSY-1, RDSY, REY were chosen as the catalyst, although we changed all the conditions, no 2246 product was obtained.The other way is using 2-tertiary butyl-4-methylphenol and paraformaldehyde as raw materials. After changing the conditions of the reaction like catalyst amount, surfactant Span 80 amount, solvent amount, reaction time, temperature, the ratio of raw materials, we confirmed how those conditions worked on the yield and purity of 2246. When DNW-1 was chosen as the catalyst, the better reaction conditions of were as follows: 2-tertiary butyl-4-methylphenol 20.5g, paraformaldehyde 3.85g, DNW-1 12g, n-heptane 100ml, Span 80 0.5g, reaction temperature 84-86℃, reaction time 4.5h, the yield (corresponding purity) of 2246 was 94.6%(96.6%), and the melting point was 125-128℃. When solid super acid SO₄^2-/TiO₂ was chosen as the catalyst, the better reaction conditions of were as follows: 2-tertiary butyl-4-methylphenol 20.5g, paraformaldehyde 3.85g, SO₄^2-/TiO₂ 4g, n-heptane 100ml, Span 80 0.5g, reaction temperature 84-86℃, reaction time 6h, the yield (corresponding purity) of 2246 was 80.1%(81.3%), and the melting point was 126-130℃.