Study On Industrial Amplification Of 2-Methylnaphthalene To 2-Methyl-1,4-Naphthoquinone By Catalytic Oxidation

As the important intermediate of synthesis of vitamin K, synthetic derivatives of 2-Methyl-1,4-naphthoquinone were widely used in agriculture, industry, animal husbandry, pharmaceutical and other fields. 2-Methyl-1,4-naphthoquinone was prepared through gas-solid catalytic oxidation method in this paper. Considering the research on the preparation of 2-Methyl-1,4-naphthoquinone through air oxidation using 2-methylnaphthalene was still in the laboratory stage both at home and abroad,the technological process of industrial single tube amplifier experiment was established and various technical problems were verified in this paper. The process parameters of industrial single tube amplifier experiment on air oxidation of2-methylnaphthalene were systematically investigated, and the performance of the vanadium catalyst made by our workgroup was evaluated on the industrial single tube amplifier experiment.Through the evaluation data and based on the industrial design, the technological process of industrial single tube amplifier experiment, the structural style and heating mode of the reactor were confirmed; Considering this technology was strongly exothermic and had quick reaction rate, the various technical problems needed to be verified were confirmed, which could provide technical reference for the production process, preparation and improvement of the catalyst.The ways of packing catalyst, production techniques and emergency shutdown process were explored. Through the single-factor experiment and orthogonal experiment, the effect of the critical factors such as reaction temperature, space velocity and feed concentration on the single-pass quality yield and conversion was studied, and the optimum process parameters of the industrial production of2-Methyl-1,4-naphthoquinone through air oxidation using 2-methylnaphthalene were as follows: reaction temperature 390 ℃, space velocity 5000 h-1, mass ratio of2-methylnaphthalene to air 1:30, conversion of 2-methylnaphthalene no less than64%, selectivity of 2-Methyl-1,4-naphthoquinone more than 35%, single-pass qualityyield of 2-Methyl-1,4-naphthoquinone more than 24%. The importance of these factors that influencing the react was as follows: reaction temperature> air flow rate in the single tube> mass ratio of 2-methylnaphthalene to air.The self-made catalyst for scale-up was characterized by BET, and the result of the comparison between laboratory scale and scale-up showed that the two catalysts had the similar physical property data. The crystal type, morphology and thermal stability of the catalyst before and after use were characterized by SEM, XRD and TG-DSC, and the result showed that: the particle size had no changes, and the particles was regular and uniform and had good dispersion, what’s more, there was no collapse and agglomeration. It had good phase stability, activity, selectivity and thermal stability, and there was no big composition change, which would help the quality control of the amplified preparation of the catalyst.