Preparation Of 2-methyl-1, 4-naphthaquinone By Oxidation Of 2-methyl Naphthalene With Air And Catalyst

2-methyl-1,4-naphthoquinone is an important material to prepare vitamin K and widely used as the middle product of feedstuff, with the improvement of the science and technology, it can be used to prepare more medicine that have biological activity. Usually, the 2-methyl-1,4-naphthoquinone is prepared by liquid-phase oxidation, but this technique have many disadvantages, such as the production restriction, high scale of pollution and difficult liquid waste disposal, etc. In this article, the 2-methyl-1,4-naphthoquinone is prepared by gas phase catalysis oxidation of 2-methyl naphthalene, this process is clear and have many other advantages, such as low-cost raw material and oxidant, simple production engineering.The active ingredient of catalyst, carrier and preparation method of the catalyst are determined by compared to the other related, and V₂O₅ is selected to be the key component of the catalyst, K₂SO₄ is the catalyst promoter, silica gel is the carrier and the catalyst is executed by dip-molding.The effect of expanding of carrier to catalyst's activity is emphasized, and the result shows that the activity of catalyst which prepared by expanded carrier loading the active ingredient is better than the catalyst which prepared by unexpanded carrier loading the active ingredient.The solubility of 2-methyl-1,4-naphthoquinone in the ethanol, acetone and toluene are measured, and toluene is determined to be the most suitable solvent.The reaction temperature is researched and 648K is the most feasible reaction temperature.The air flow rate is studied, and it can be effect the quantity of oxygen entering into the reactor, the input quantity of 2-methyl naphthalene and the contact time. The result displays that the contact time is the major influence factor. The most suitable contact time is between 1.0 s and 1.2 s.And under the all suitable conditions, the yield of 2-methyl-1,4-naphthoquinone can beyond 30%, and the selectivity can beyond 70%.