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Paint light stabilizers
It is the most effective antioxidant for most oils, especially vegetable oils. T-butylhydroquinone, abbreviated as TBHQ, has a molecular formula of Cl0H1402 and a molecular weight of 166.22. [1] It is a white to light gray crystalline or crystalline powder with a very slight special odor. It is soluble in ethanol, acetic acid, ethyl ester, isopropanol, ether, and oils, and is almost insoluble in water (25 ℃,<1%; 95 ℃, 5%).
When the tert butanol process encounters bottlenecks, replacing tert butanol with isobutene is a feasible breakthrough direction. Patent [10] discloses a method for preparing 2-tert butylhydroquinone and co producing BHA using isobutene as an alkylation reagent, which has good selectivity and high raw material utilization rate.
At present, the most commonly used antioxidants for oils and their products are BHA, BHT, PG, TBHQ, and tocopherols. As for vegetable oils, their antioxidant capacity is in the order of TBHQ>PG>BHT>BHA. As for animal fats, the order of their antioxidant capacity is TBHQ>PG>BHA>BHT. For anhydrous milk fat, their antioxidant capacity is in the order of PG>TBHQ>BHA>tocopherols. For certain processed foods rich in oil, such as fried potato chips, which have a large surface area and are prone to oxidation and spoilage, the order of antioxidant capacity is: TBHQ>PG>BHT>BHA.
The selectivity of the single tert butylation reaction can reach over 90%. Cationic resin [9] can also serve as a catalyst for this reaction, but the effect is not very ideal. Isobutene has higher activity than tert butanol, and its application and promotion prospects are very optimistic. When the tert butanol process encounters bottlenecks, replacing tert butanol with isobutene is a feasible breakthrough direction. Patent [10] discloses a method for preparing 2-tert butylhydroquinone and co producing BHA using isobutene as an alkylation reagent, which has good selectivity and high raw material utilization rate.
The tert butanol method is widely used and can be catalyzed by strong acids such as concentrated sulfuric acid and concentrated phosphoric acid. Both domestic and foreign patent literature have reported this process, such as using toluene or xylene as solvents, the selectivity and yield of this reaction are relatively ideal. In addition, strong acidic ion exchange resins such as D001 and Amberlyst 35, solid acids [5], zeolites [6], and ionic liquids [7] can also be used as catalysts for this reaction, but their catalytic activity is not ideal.
