Antioxidant 245: Preparation, Analytical methods and Applications in Polymers

General Description

The production of Antioxidant 245 involves a catalyzed transesterification reaction, resulting in the formation of the hindered phenolic compound. This method offers benefits such as efficiency, minimal energy consumption, and eco-friendliness. Analytical methods have been developed to assess its stability in fatty food simulants, demonstrating no observed instability under specified exposure conditions. These methods enable the determination of additive stability and migration into olive oil, contributing to the safety of food packaging materials. Antioxidant 245 is widely used in various polymers to protect against thermal oxidative degradation, serving as a chain terminator during PVC polymerization and extending the service life of polymer materials while maintaining their physical properties. Its unique molecular structure enables it to scavenge free radicals and inhibit oxidation reactions, making it an essential component for polymer stabilization.

Figure 1. Antioxidant 245

Preparation

The preparation of Antioxidant 245, an asymmetric hindered phenolic compound, involves a series of key steps that culminate in its formation. Initially, Me 3-(3-tert-butyl-4-hydroxy-5-methyl-phenyl)propanoate and triethylene glycol are mixed in a reactor to create an initial mixture. Subsequently, a catalyst is added to the mixture, and the temperature is raised to trigger a transesterification reaction. This chemical process leads to the creation of benzenepropanoic acid, 3-(1,1-dimethylethyl)-4-hydroxy-5-methyl-, 1,1'-[1,2-ethanediylbis(oxy-2,1-ethanediyl)] ester, which is known as Antioxidant 245. This innovative method offers various benefits, including a straightforward procedure, high catalytic efficiency, minimal energy consumption, high product yield and purity, and cost-effectiveness. Moreover, it upholds safety and environmental sustainability, aligning well with the principles of green chemistry. In conclusion, the preparation method for Antioxidant 245 exemplifies both efficacy and eco-friendliness in the production of this significant compound. ¹

Analytical methods

The analytical methods for Antioxidant 245, a type of Irganox-type polymer antioxidant, were developed to assess its stability in fatty food simulants. A reversed-phase HPLC (RP-HPLC) was employed to measure the stability of Irganox 245 in both olive oil and isooctane, serving as alternative fatty food simulants. The tests were conducted under various conditions, including exposure to 40°C for 10 days, 100°C for 1 hour, 175°C for 1 hour in olive oil, and 60°C for 3 hours in isooctane. Notably, no instability phenomena were observed for Irganox 245 in either olive oil or isooctane under the specified exposure conditions. The analytical methodology developed for Antioxidant 245 holds the potential for application in stability testing and migration studies of similarly structured antioxidants in fatty food simulants. Furthermore, specific methods for the analysis of Antioxidant 245 in olive oil simulant at sub-mg kg-1 levels were reported. These methods, which are simple, rapid, and cost-effective, involve direct injection of an olive oil solution for high-performance liquid chromatography (HPLC) analysis with UV-visible or fluorescence detection. These methods enable the determination of additive stability and measurement of migration of Antioxidant 245 into olive oil under different time-temperature conditions relevant to migration studies in food simulants. The development of these analytical methods provides valuable tools for assessing the behavior of Antioxidant 245 in food-contact materials and contributes to ensuring the safety and quality of food packaging materials. ²

Applications in polymers

Antioxidant 245 is a sterically hindered phenolic antioxidant widely used in polymers to protect organic substrates from thermal oxidative degradation during production, processing, and final use. Specifically designed for styrenic polymers such as impact-modified polystyrene, ABS, MBS, SB, and SBR rubbers, as well as POM homopolymers and copolymers, Antioxidant 245 also finds application in polyurethanes, polyamides, thermoplastic polyesters, PVC, and various other polymers for stabilization purposes. Apart from imparting thermal stability to the finished polymer products, it serves as an effective chain terminator during the PVC polymerization process. The unique molecular structure of Antioxidant 245 allows it to scavenge free radicals and inhibit oxidation reactions, thereby extending the service life and maintaining the physical properties of the polymer materials throughout their lifecycle. ³

Reference

1. Chen FX, He JY, Dai J. Green preparation of asymmetric hindered phenolic antioxidant 245. 2022. Patent Number: CN115850066.

2. QUINTO-FERNÁNDEZ EJ, Pérez-Lamela C. Analytical methods for food-contact materials additives in olive oil simulant at sub-mg kg-1 level. Food additives and contaminants. 2003. 20(7): 678-683.

3. IRGANOX® 245. Dispersions, Resins and Additives, North America.