Synthesis Of Intramolecular Compound Antioxidant With Multi-function And Low Toxicity

The compound antioxidants have a lot of advantages, such as short development cycle, good general function, nice synergism, and convenience for customers, so it has been the main trend of the development of antioxidant industry. And with the study of mechanism of compound antioxidants, the intramolecular compound antioxidant has already appeared, which gets the hot stabilizer function and light stabilizer function together. This type usually has synergism action, so it can largely increase the capability of resistanting heat oxygen, brightness, and effusion. The synthetical product, pentaerythritol diphosphite bis(3,5-di-tert -butyl- 4-hydroxyphenyl) methyl ester, is a new type of multi-functional intra-molecular compound antioxidant, and it provides basis for compound technology, also it is an example of multi-functional intra-molecular compound antioxidant.The study contains three segments. Firstly, a new type of multi-functional intramolecular compound antioxidant, pentaerythritol diphosphite bis(3,5-di-tert- butyl- 4-hydroxyphenyl) methyl ester, was prepared by phenol aldehyde addition and two steps transesterification. The influences of different catalysts and quantity of catalyst used, reaction temperature, reaction time and molar ratio of raw materials on the yield of the product were studied in experiments. Secondly, the molecule structure of the product was characterized by measuring melting points of products, determination of total phosphorus and IR. Thirdly, the performance of the final product was tested by thermogravimetric analysis, hydrolytic stability, oxidative inductive time, and MFR.The results show that the best conditions of the first step are as follows: catalyst used potassium tert-butoxide and quantity 3wt% of 2, 6-di-tert-butylphenol; reaction solvent tert-butyl alcohol; reaction time 4h; reaction temperature 20℃; recrystal solvent hexane; and molar ratio of 2,6-di-tert-butyl phenol to paraformaldehyde is 1:2.5. The conditions of the second step are as follows: catalyst used organic tin and quantity 0.8wt% of intermediate pentaerythritol diphosphite; reaction time 2h; reaction temperature 140℃; and molar ratio of pentaerythritol to triethyl phosphate is 1:2.05. The conditions of the third step are as follows: catalyst used organic tin and quantity 1.0wt% of the final product; reaction time 2h; reaction temperature 90℃; and molar ratio of pentaerythritol diphosphite to 4-Hydroxymethyl -2,6-di- tert-butyl-phenol is 1:2.2. The characterizations proved that the products are identical with the target product. Thermogravimetric analysis, hydrolytic stability, hydrolytic stability, oxidative inductive time and MFR show that the stability and anti-oxidative property are good.