Study On The Synthesis Of Antioxidants Of PEP-36 And Dodecyl Phenol

In this thesis, the phosphite antioxidants, (Bis (2,6-di-ter-butyl-4-methylphenyl) pentaerythritol diphosphite (PEP-36), and the alkyl phenol antioxidant, dodecyl phenol, were synthesized.(1) Study on Synthesis of antioxidant PEP-36Through the discussion of two kinds of synthetic process, PEP-36 was synthesized from pentaerythritol, phosphorus trichloride and 2,6-di-tert-butyl-4-methylphenol (BHT), catalysis by triethylamine. Two steps were needed for this synthesis:the first step was the cyclization reaction between pentaerythritol and phosphorus trichloride, and the intermediate product was dichloropentaerythritol diphosphite; the second step was the substitution reaction between dichloropentaerythritol diphosphite and BHT, and the resulted reaction product was PEP-36. Triethylamine was added as acid binding agent in the second step.According to the single factor experiment and orthogonal experiment, the optimized conditions were obtained. The molar ratio of pentaerythritol, phosphorus trichloride and BHT was 1:2.4:2.4. The dosage of catalyst was 0.5% accounting for the mass of pentaerythritol The first reaction was carried out at 110 ℃ for 12 h, while the second reaction at 125 ℃ for 12 h. Triethylamine was added as acid binding agent in the second step accounting for the equal molar of BHT. The product yield was 70% with the purity of more than 98%.The product was identified by FTIR,1H-NMR、13C-NMR、MS, and the melt flow rate test showed that PEP-36 had antioxidant effect to some extent on polypropylene plastics.(2) Study on Synthesis of dodecyl phenolThe dodecyl phenol producted by manufacturer has the problems such as performance instability, each batch of products differ greatly in nature and the color of the products unqualified. Through the study of phenol pretreatment, found problems in raw phenolpartial oxidation and moisture content is too high, the vacuum drying treatment of phenol after solving the problem.According to the single factor experiment, the optimized conditions were obtained, the molar ratio of phenol and propylene tetramer was 1.3:1, catalyst dosage of phenol was 5%, reaction temperature was 140℃ reaction time was 6h. The product yield was 85.79%～87.84% with the color of pale yellow transparent. The product was identified by IR and1H-NMR.