Study On Synthesis Of Antioxidant PEP-36

Bis（2,6-di-tert-butyl-4-methylphenyl）pentaerythritol diphosphate,referred to as antioxidant PEP-36 is a phosphite antioxidant,developed by ADEKA in the 1980s.Antioxidant PEP-36 contains blocked phenol and double helix structure,which has high antioxidant efficiency,good hydrolysis resistance and thermal stability.It can effectively prevent the thermal oxygen aging of polymer materials in the process of processing,inhibit the discoloration caused by heat and ultraviolet light,and improve the photostability of products.In PP,PE,PVC,PS,PC,ABS,polyester and other polymer materials have a broad application prospect.The main manufacturer of this product is the Japanese company ADEKA,and there is no report of industrial production in China.At present,the synthesis process of the antioxidant PEP-36 proposed in the literature is complicated,and the yield is generally lower than 70%.In this thesis,the synthesis of antioxidant PEP-36 by phosphorus trichloride esterification was determined,and the main influencing factors in the synthesis process of antioxidant PEP-36 were optimized by single-factor test,and a better synthesis process was obtained with a product yield of 79%,which is higher than the domestic and foreign literature values.The optimized process conditions were as follows:pentaerythritol,2,6-di-tert-butyl-p-methylphenol（BHT）as raw materials,triethylamine as catalysts,toluene as reaction solvent,toluene trichloride solution was added slowly dropwise at 10°C,and the temperature was gradually increased to 75°C after the dropwise addition,and the reaction was completed when no hydrogen chloride gas was generated in the reaction system.The molar ratio of n（pentaerythritol）:n（BHT）:n（PCl3）was 1:2.4:1.05;m（triethylamine）:m（pentaerythritol）was 1:6.In the second step,n-tetrabutylammonium bromide was added as catalyst;m（tetrabutylammonium bromide）:m（pentaerythritol）was 7:150 and triethylamine was added to neutralize the reaction system to p H 9-10;and the reaction temperature was 110°C,and the reaction was held for 2 h.After the reaction,the reaction mixture was filtered at 110°C,and the filtered mother liquor was cooled down to 20°C and filtered to obtain the white powder crude antioxidant PEP-36.The crude product was finally obtained as a finished product.This thesis developed a method to detect the purity of the antioxidant PEP-36 by HPLC and combined with digital melting point apparatus and acid-base titration to test various physicochemical parameters of the product.The molecular structure of the antioxidant PEP-36 was also determined by ¹H NMR and ¹³C NMR,FT-IR,etc.to match that of the competing products.The performance application of self-produced PEP-36 was evaluated in comparison with competitive products by adding 0.3 wt%of antioxidant to polypropylene for thermal-oxidative aging,mechanical properties,and oxidation induction period tests.The 1000h hot-oxidation aging test revealed that the addition of antioxidant PEP-36reduced the yellowing resistance of polypropylene fromΔE1000h 8.21 toΔE1000h5.14,which was basically the same as theΔE1000h 5.08 of the competitor.The oxidation induction time increased from 38.6 min to 67.37 min,which was higher than that of the competitor’s 58.79 min.The application experiment revealed that the self-produced antioxidant PEP-36 was better than the competitor’s in terms of application performance.Based on the completion of the laboratory process study,the industrial production of the antioxidant PEP-36 is designed and planned on the basis of the defined process.The analysis is carried out through safety analysis,three waste treatment and economic benefits.The analysis results show that the process developed in this thesis is suitable for industrial production...