Process Research Of Preparing1,5-diaminonaphthalene Via Naphthalene’s Amine Oxidation

1,5-diaminonaphthalene is a very important raw material for industry in organicsynthesis, its applications in pigment, dye, medicine, pesticide, rubber chemicals, resin,photosensitive materials and many other fine chemical products are gradually increasing,especially with huge demand growing of senior polyurethane(PU), studies on synthesismethod of PU continue to increase. Typical preparation methods of1,5-Diamino-naphthalene, such as nitration reduction of naphthalene, amination substitution method,generally have multiple steps, which always come out with more by-products andenvironment pollution, so they are not fit the requirements of green chemistry. One-stepsynthesis of diaminonaphthalene via direct amination of naphthalene is apparentlyincreased atomic economy of the process, otherwise, because of mild reaction conditions,its raw materials and products have low environmental hazards, research of one-stepamination of naphthalene has important significance.In this study, HPLC is used to quantitatively analyze naphthalene and its products ofone-step amination reaction. Firstly, by impregnation method, this study use Mo, Mn, Nias active components to prepare one-component supported catalysts with different loadingcapacity and characterize them with BET, XRD and TPR. Based on one-componentsupported catalysts, this study prepare two-component supported catalysts with differentV-Mo ratio, and then characterize these catalysts by different characterization methods.10%Mo/γ-Al2O3is chosen to be the catalyst for this one-step amination reaction forthe best catalytic activity after reaching reaction results. After studying reaction solvent,reaction temperature, reaction time, amount of hydrogen peroxide and ammoniumhydroxide when both the amount of hydrogen peroxide and ammonium hydroxide are5g,the optimum conditions are: solvent N, N–dimethylformamide is20g, reactiontemperature is65℃, reaction time is2h. Besides, effects of the amount of hydrogenperoxide and ammonium hydroxide to the reaction are studied. It comes out that when theamount of ammonium hydroxide is5g constantly, product yield is improving with theincrease of hydrogen peroxide. When ratio of hydrogen peroxide and ammoniumhydroxide is2:1, the best yield is gained. But when the amount of hydrogen peroxide isconstant, increasing the amount of ammonium hydroxide make barely difference to thereaction. This result shows that oxidation ability of hydrogen peroxide is the key factor toaccelerate the activation of C-H bonds in naphthalene molecule or is more important for the interaction of hydrogen peroxide and ammonium hydroxide to form hydroxylamineprocess. Results of the reactions catalyzed by V-Mo two-component supported catalyst areboth better than the one-component supported catalyst. The yield of1,5-diaminonaphthaleneis growing with the increasing of V-Mo ratio, when ratio of V-Mo is0.08, the yield ofreaction catalyzed by V-Mo two-component supported catalyst is5.12%.