Naphthalene Nitrification To Dinitronaphthalene Over Solid Superacid

1,5-dinitronaphthalene and 1,8- dinitronaphthalene are very important intermediates, plays an important role in the chemical, pharmaceutical, pesticide and so on. 1,5-dinitronaphthalene can synthesize 1,5-diaminonaphthalene with hydrogenation, then Synthesize NDI.NDI as a kind of new material, is of high temperature resistance, wear resistance, oil resistance and other superior performance. 1,8-dinitronaphthalene can synthesize 1,8-diaminonaphthalene with hydrogenation, mainly used in the production of dyes and plastics, also can be used as a resin or pesticide raw materials. Currently the industry commonly used in the preparation of 1,5-dinitronaphthalene is sulfur nitrate mixed acid, This technology is relatively mature, but there are certain drawbacks : Atom utilization is low; the method of dealing with waste acid is complex, and it causes serious environmental pollution; The selectivity of dinitronaphthalene is low. In order to improve these problems, improve the selectivity of dinitronaphthalene and meet national green chemical requirements, this paper puts forward feasible suggestions for the liquid-phase catalytic nitration of naphthalene. It mainly uses the 65% concentrated nitric acid and 95% fuming nitric acid as nitrating agent, to explore the zeolite molecular sieve and solid superacids as catalyst on the impact of naphthalene nitration product.on the first,this paper studies 65% nitric acid and 95% fuming nitric acid nitrating naphthalene on the single factor investigation, respectively, to explore the reaction time, reaction temperature, reactant ratio and other factors, the optimum conditions are determined in the absence of catalyst conditions. The experimental results show : 65% nitric acid nitrating naphthalene,The main products are 1- nitro naphthalene,1,5-dinitronaphthalene, and 1,8-dinitronaphthalene. With the increase of temperature, reaction time, the ratio of nitric acid and naphthalene, 1- nitronaphthalene gradually reduces, transformed into dinitronaphthalene. The optimal reaction conditions:the reaction temperature is 80 ?, reaction time is 8 hours, the ratio of nitric acid and naphthalene is 10: 1. The conversion rate of Naphthalene is 100%,The yield of 1,5-dinitronaphthalene is 29.78%, the yield of 1,8-dinitronaphthalene is 35.25% The total yield of dinitronaphthalene is 65.03%.This paper inspects zeolite molecular sieve as a catalyst, dichloroethane as the solvent, zeolite molecular sieve as a catalyst, fuming nitric acid nitrates naphthalene, under the optimal process reaction conditions, results showed that it didn't improve the selectivity of 1,5-dinitronaphthalene, instead the selectivity of 1,8- dinitronaphthalene had certain improvement under the optimum conditions.Compared to 1,5-dinitronaphthalene, H-ZSM-5 as a catalyst is of better selectivity. Zeolite molecular sieve which have different ratios of silicon and aluminum for the Selectivity of 1,5-dinitronaphthalene has a slightly different, but effect is better without catalyst. The H-ZSM-5?Si/Al=25? as catalyst, the yield of 1,5-dinitronaphthalene reached 27.86%, he yield of 1,8-dinitronaphthalene reached 45.06%.This paper uses precipitation to prepare several different solid super acid catalysts, and examine them under the conditions of fuming nitric acid, concentrated nitric acid as the nitrating agent. Experimental results show, Under the system of fuming nitric acid, solid super acid catalyst, the selectivity is relatively low for nitronaphthalene. Under the system of nitric acid, solid super acid catalyst can improve the to selectivity of dinitronaphthalene. SO₄^2-/ Fe2O3 as a catalyst, the yield of dinitronaphthalene is 73.21%, the selectivity of 1,5- dinitronaphthalene is 33.83%, slows down the generation of 1,8-dinitronaphthalene, improves the ratio of 1,5-dinitronaphthalene and 1,8-dinitronaphthalene. Compared with no catalyst, SO₄^2-/Al2O3 and SO₄^2-/SnO₂ as catalyst, the yield of dinitronaphthalene is low, and the yield of 1,5-dinitronaphthalene doesn't improve, but for the generation of 1,8-dinitronaphthalene has certain influence, which improves the ratio of the 1,5-dinitronaphthalene and 1,8-dinitronaphthalene. SO₄^2-/ CrO₂ as catalyst, Improve the yield of the dinitronaphthalene reached 86.03%. But it doesn't significantly improve the yield of 1,5-dinitronaphthalene, It has to improve the yield of 1,8-dinitronaphthalene, reaching 47.95%. SO₄^2-/ZrO₂ as a catalyst, the yield of dinitronaphthalene has certain increase, reaching 86.01%, relative to the yield of 1,8-dinitronaphthalene has no obvious increases. while SO₄^2-/ZrO₂ has certain promoting effect on the production of 1,5-dinitronaphthalene,the yield of 1,5-dinitronaphthalene reaches 39.42%.