Abstract: Butylated hydroxytoluene (BHT) is commonly used as food additive, but the oxidation of BHT leads to a decrease in its antioxidant effect and the generation of toxic products. In order to investigate the effect of acids and bases on the oxidation of BHT, KOH and HCl were added to carry out the oxidation reaction of BHT, and the consumption of BHT at atmospheric pressure was determined by high-performance liquid chromatography (HPLC). The temperature and pressure changes of BHT oxidized at high pressure were tracked by a mini closed pressure vessel test (MCPVT). The oxidation products of BHT were structurally characterized and the possible pathways of BHT oxidation were speculated. The results showed that BHT was relatively stable at atmospheric pressure. In the presence of HCl, BHT conversion was less than 5%, indicating that no oxidation occurs. However, a 2% molar ratio of KOH ed the oxidation reaction of BHT even at a temperature of 20 °C. The initial oxidation temperature of BHT was 159.8 °C in a high-pressure closed vessel, and both KOH and HCl decreased the initial oxidation temperature of BHT to 67.2 °C and 55.2 °C, respectively. The toxic metabolite BHTOOH and the polymer BHT-PQD were produced under both atmospheric and high-pressure conditions.

Key words: butylated hydroxytoluene, food additive, oxidation reaction, a mini closed pressure vessel test (MCPVT), the initial oxidation temperature