Study On Synthetic Process Of Rubber Antioxidant 4030 By Catalytic Hydrogenation

Rubber Antioxidant 4030 is a highly effective multi-functional protective agent that can be widely used in the rubber industry,especially under static conditions.However,there are few reports on this additive in China.Based on a platinum carbon catalyst,5-methyl-2-hexanone and p-phenylenediamine are used as raw materials to catalyze the synthesis of rubber antioxidant 4030.The preparation method of the catalyst,the synthesis process of the rubber antioxidant,the deactivation mechanism of the catalyst and the regeneration treatment were mainly studied.The effects of various preparation conditions of the catalyst on the catalytic synthesis of antioxidant 3030 were investigated.The mechanism of catalyst deactivation was preliminarily determined,and the deactivated catalyst was regenerated.Based on three kinds of commercial activated carbon,the surface functional group type and content,specific surface area,pore volume,ash and particle size were investigated comprehensively,and AC2 activated carbon suitable for catalyst carrier was selected.The AC2 activated carbon was used as the catalyst carrier.The optimum conditions for the synthesis of the catalyst were obtained by single factor experiment.The pH of the impregnation solution was 2.5,the concentration of the impregnation solution was 1.5mg/mL,the temperature of the impregnation solution was 80°C,and the immersion time was 2 h.The reducing agent sodium borohydride is 70 mg,the reduction temperature is65°C,and the platinum loading is 3%.The optimum process of the rubber anti-aging agent 4030 was obtained by single-factor condition experiment with activated carbon AC2 loading 3%platinum.The reaction temperature was 110°C,the hydrogen pressure was 4.5 MPa,and the catalyst mass fraction is 1.4%.The ketone amine molar ratio was 3:1 and the agitation rate was650 rpm.After ten times of application,the yield of antioxidant 4030 can still be maintained above 97%,and the conversion of p-diphenylamine is maintained above 99%.When 5%fresh catalyst is added,the yield of the antioxidant and the conversion of p-diphenylamine can be returned to more than 99%.Preliminary studies have shown that the deactivation of the catalyst is mainly due to the fact that some organic matter and carbon deposits cover the active metal surface during the reaction,resulting in a decrease in the surface area of the active metal.After supercritical CO₂ plus ethanol regeneration,the performance of the catalyst can be greatly improved,which is basically equivalent to fresh catalyst.