[Overview]
Distearyl pentaerythritol phosphite, also known as antioxidant 618, its chemical name is 3,9-di(octadecyloxy)-2,4,8,10-tetraoxo-3,9 -Diphospiroundecane is a new type of phosphorus-containing antioxidant with excellent performance. It has high effective phosphorus content and strong ability to decompose hydroperoxides. It can effectively inhibit the auto-oxidation reaction of polymer materials and delay the aging of materials. Degradation speed, its application involves almost all polymer products, and is widely used in various synthetic resins such as polypropylene, polyethylene, PVC, ABS, ethylene-vinyl acetate copolymer, etc. It can prevent resin discoloration and improve heat resistance. , weather resistance, processing stability and high temperature volatility resistance. This product has low toxicity and no pollution, and can be used as an antioxidant for synthetic resins used in food and food packaging, replacing antioxidant 264 (2,6-di-tert-butyl-4-cresol, also known as BHT); and UV rays The combined use of absorbers, hindered phenolic antioxidants such as 1010, 1076, and 1790 and hindered amine light stabilizers can produce better synergistic effects.
[Introduction]
Since there are pentaerythritol groups of free radical scavengers and phosphite groups of hydroperoxide decomposers in this molecule, the free radical scavengers and hydroperoxide decomposers are compounded in one molecule. , this compound is a molecular composite antioxidant and heat stabilizer. It can produce synergistic effects when used together with hindered phenols or hindered amine stabilizers. The trade name is Weston618/619 or JPP618. It is a new type of high-performance phosphorus-containing antioxidant with excellent prospects.
【Synthesis】
Chemical synthesis route and reaction principle Regarding the synthesis method of this product, there are currently three main literature reports: 1. Triphenyl phosphite method (phenol method) The reaction is carried out in two steps:
Figure 1 shows the synthesis route of distearyl pentaerythritol phosphite using triphenyl phosphite method (phenol method). This method uses triphenyl phosphite as the raw material, which is expensive and causes high production costs. In addition, it can be seen from the reaction formula that in addition to the target product, the products produced by this method also have phenol that is easily oxidized and discolored, and stearic acid cannot be removed. , affecting product quality and also limiting the application of products in food and pharmaceutical packaging. 2. Triethyl phosphite transesterification method (phenol-free method): Use ethanol and phosphorus trichloride to react in the presence of an acid binding agent to prepare triethyl phosphite, and then combine triethyl phosphite with pentaerythritol and stearin The reaction with alcohol gives 618.
Polyurethane coating
Figure 2 shows the synthesis route of distearyl pentaerythritol phosphite using triethyl phosphite transesterification method (phenol-free method). The triethyl phosphite transesterification method can solve the problem of residual phenol. The production cost is similar to that of the triphenyl phosphite method. However, triethyl phosphite is not as stable as triphenyl phosphite and production is more troublesome. This method has been studied relatively little. 3. Phosphorus trichloride direct method (phenol-free method) uses phosphorus trichloride, pentaerythritol and stearyl alcohol as raw materials, and uses organic amines as acid binding agents to absorb hydrogen chloride gas. The resulting product does not contain phenol, has high yield, and is produced The conditions are mild, the production equipment is simple, and industrialization is easy to achieve. The principle is as follows:
Figure 3 shows the synthesis route of distearyl pentaerythritol phosphite from triethyl phosphite and phosphorus trichloride by direct method (phenol-free method) and transesterification method (phenol-free method).
[Application]
Distearyl pentaerythritol diphosphite is mainly used as an auxiliary antioxidant for various synthetic resins such as polyethylene, polypropylene, polyvinyl chloride, ABS resin, and polyester. It has outstanding effects on preventing oxidation and improving color; it has high thermal stability, weather resistance and hydrolysis resistance, so it has good processing stability and good product transparency; it does not pollute and is compatible with ultraviolet absorbers. , the combined use of phenolic antioxidants has a good synergistic effect. It is also a good food antioxidant. Due to its low toxicity, it can replace the food antioxidant BHT. It has passed the FDA certification of the US Food and Drug Administration. This product is produced abroad by General Electric Company, Borg-Hana Corporation of the United States, and Johoku Chemical Company of Japan. It is produced and applied by Jilin Chemical Company domestically.
[References]
[1] Tang Rongping, Hou Xia. Research on the synthesis process of phenol-free distearyl pentaerythritol phosphite [J]. Journal of Lanzhou Petrochemical Vocational and Technical College, 2008(01):1-4.
[2] Pan Chaoqun, Zhang Yajun, Huang Kuo. New synthesis process of antioxidant distearyl pentaerythritol diphosphite [J]. Chemical Engineer, 2006(02):14-16.
[3] Zhang Xiaojun. Distearyl pentaerythritol diphosphite passed provincial identification [J]. Fine Petrochemicals, 1998(04):30.
