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HZSM-5-supported phosphotungstic acid (PW) has been prepared and characterized. The results indicate that 5 wt% PW/HZSM-5 calcined at 773 K has the largest surface area and high dispersion of PW. It was confirmed that Keggin units are present inside the catalyst and that the proton of PW and the silanol of HZSM-5 interact via bridging structure. The catalytic properties of PW/HZSM-5 in the regioselective nitration of naphthalene to dinitronaphthalene were investigated. The best results, i.e. 48.5 % yield of 1,5-dinitronaphthalene, 49.2 % yield of 1,8-dinitronaphthalene, and the highest ratio of 1,5-dinitronaphthalene to 1,8-dinitronaphthalene, were obtained by use of 5 wt% PW/HZSM-5.

The excited triplet state of 1-nitronaphthalene, 1NN, (31NN) is able to oxidise nitrite to NO2, with a second-order rate constant that varies from (3.56 ± 0.11) × 108 M-1 s-1 (μ ± σ) at pH 2.0 to (3.36 ± 0.28) × 109 M-1 s-1 at pH 6.5. The polychromatic quantum yield of NO2 photogeneration by 1NN in neutral solution is ΦNO21NN ≥ (5.7 ± 1.5) × 107 × [NO2-]/{(3.4 ± 0.3) × 109 × [NO2-] + 6.0 × 105} in the wavelength interval of 300-440 nm. Irradiated 1NN is also able to produce OH, with a polychromatic quantum yield ΦOH1NN = (3.42 ± 0.42) × 10-4. In the presence of 1NN and NO 2-/HNO2 under irradiation, excited 1NN (probably its triplet state) would react with NO2 to yield two dinitronaphthalene isomers, 15DNN and 18DNN. The photonitration of 1NN is maximum around pH 3.5. At higher pH the formation rate of NO2 by photolysis of NO2-/HNO2 would be lower, because the photolysis of nitrite is less efficient than that of HNO2. At lower pH, the reaction between 31NN and NO2 is probably replaced by other processes (involving e.g.31NN-H+) that do not yield the dinitronaphthalenes. The Royal Society of Chemistry and Owner Societies 2011.

A simple method for the preparation of dinitronaphthalene from the nitration reaction of 1-nitronaphthalene with NO2 as nitration reagent under the mild conditions has been successfully developed in this work. The results indicated that Ni(CH3COO)2·4H2O catalyst shows better catalytic performances, and the conversion of 1-nitronaphthalene is 33.10 % with 34.10, 23.56, 19.30, and 3.56 % of the selectivity to 1,5-DNN, 1,3-DNN, 1,4-DNN, and 1,8-DNN, respectively, under the optimal reaction conditions. This is a mild, environmentally benign, and economical method for the preparation of dinitronaphthalene.

Regardless of the sustainable development path, today, there are highly demanded chemical productions still operating that bear environmental and technological risks inherited from the previous century. The fabrication of nitro compounds, and nitroarenes in particular, is traditionally associated with acidic wastes formed in nitration reactions exploiting mixed acids. However, nitroarenes are indispensable for industrial and military applications. We faced the challenge and developed a greener, safer, and yet effective method for the production of nitroaromatics. The proposed approach comprises the application of an eco-friendly nitrating agent, namely dinitrogen pentoxide (DNP), in the medium of liquefied 1,1,1,2-tetrafluoroethane (TFE) - one of the most non-hazardous Freons. Importantly, the used TFE is not emitted into the atmosphere but is effortlessly recondensed and returned into the process. DNP is obtainedviathe oxidation of dinitrogen tetroxide with ozone. The elaborated method is characterized by high yields of the targeted nitro arenes, mild reaction conditions, and minimal amount of easy-to-utilize wastes.

A simple and efficient method for liquid-phase catalytic nitration of 1-nitronaphthalene with NO2 to 1,5-dinitronaphthalene under mild conditions has been developed. The results indicated that the sulfated zirconia (SO42?/ZrO2) as solid superacid catalyst exhibits superior catalytic performance with dioxygen and acetic anhydride. 93.8% conversion of 1-nitronaphthalene and 52.8% 1,5-dinitronaphthalene selectivity were achieved. Furthermore, the physicochemical properties of SO42?/ZrO2 were determined by XRD, Py-FT-IR, BET, FT-IR, Raman spectroscopy and ICP-OES technologies. The possible nitration reaction mechanism over SO42?/ZrO2 catalyst was proposed. The present work provides an easy-to-implement, mild and eco-friendly approach for the efficient preparation of valuable 1,5-dinitronaphthalene, which has extensive industrial application prospects.

The invention discloses a method for preparing a nitro compound by using graphene to catalyze nitric oxide. A graphene oxide carbon material is used for catalysis of a reaction of nitric oxide and a nitrification substrate such as an aromatic compound to prepare the nitro compound. The method is used for replacing a traditional nitric acid/sulfur acid method to prepare the nitro compound, so thatthe atom utilization rate of the reaction is increased, the energy is saved, and the emission is reduced; and the method has the characteristic of atom economy during industrial preparation of the nitro compound.

The invention provides a method for preparing diaminonaphthalene. The method comprises the following steps: carrying out a nitration reaction by adopting sulfuric acid, fuming nitric acid and naphthalene so as to obtain mixed dinitronaphthalene; adding a second organic solvent, the mixed dinitronaphthalene, a catalyst and activated carbon into a reaction kettle, raising the temperature to 60-65 DEG C, adding hydrazine hydrate, and reacting and separating so as to obtain second filtrate and second filter cake; separating and purifying the second filtrate so as to obtain a solid, namely 1,8-diaminonaphthalene; and separating and purifying the second filter cake so as to obtain 1,5-diaminonaphthalene. According to the preparation of the mixed dinitronaphthalene, the nitratlon reaction is carried out by adopting an organic solvent free method, the waste acid can be recycled, and the yield and treatment cost of the three wastes can be reduced. The mixed dinitronaphthalene is directly reduced, the separation cost is reduced, and the market competitiveness is improved for industrial production. By utilizing different physical properties of the mixed dinitronaphthalene in different organic solvents, 1,8-diaminonaphthalene and 1,5-diaminonaphthalene with high purity are separated.

The invention relates to a method for synthesizing 1, 5-dinitronaphthalene and 1, 8-dinitronaphthalene by virtue of micro-channel reaction, belonging to the technical field of organic synthetic application. The method is a novel process of synthesizing 1, 5-dinitronaphthalene and 1, 8-dinitronaphthalene through nitration reaction in a transient reaction time from decades of seconds to several minutes in a Corning micro-channel reactor by taking naphthalene and nitric acid as raw materials. Materials are introduced to the Corning micro-channel reactor by virtue of a metering pump and are preheated, mixed, subjected to nitration reaction and post-treated to obtain 1, 5-dinitronaphthalene and 1, 8-dinitronaphthalene products. The method is simple, convenient and safe to operate and can be used for continuously producing dinitronaphthalene products with high yield. In addition, the environmental pollution of the process is greatly reduced.

A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.

The nitration selectivity of naphthalene was studied in different organic solvents with 95 % fuming nitric acid as nitration reagent. The yield of dinitronaphthalene can achieve 78 % in hexane. With nitrogen dioxide as nitration reagent in oxygen, the selectivity of dinitronaphthalene in different types of molecular sieve catalyst was studied. When HBEA zeolite catalyst was used, the yield of dinitronaphthalene was up to 61 %. This method is easy to carry out, environmentally benign, and economical.

Efficient methods of nitration of naphthalene or 1-nitronaphthalane with fuming nitric acid (wt. 95 %) in organic solvent over zeolite were investigated, where the regioselection of nitration can be improved and in certain cases the isomer ratio of nitration products can be reversed. The recovered zeolite was reused three times without appreciable loss of catalytic activity.

(Figure Presented) Aromatic molecules have a strong affinity for silver(I) and dissolve to a limited extent in Ag0.51K0.42Na 0.07NO3, a low-melting eutectic mixture of silver, potassium, and sodium nitrates. Aromatic nitration in this inorganic ionic liquid leads to products which arise from nonelectrophilic substitution pathways.

The invention is directed to a process for the production of 1,5-dinitronaphthalene whereina) naphthalene is nitrated by nitric acid in the absence of sulfuric acid at temperatures of from 30 - 80°C, wherein the nitric acid has a concentration of from 72 to 87 wt.-%, andb) the reaction mixture obtained in step a) is filtrated at temperatures of from 5 to 20°C and the solid precipitate obtained is washed with water, andc) 1,5-dinitronaphthalene is isolated from the washed precipitate obtained in step b) by washing with acetone.

In the presence of zeolites, moderately deactivated arenes such as 1-nitronaphthalene, naphthonitriles, and methylated benzonitriles can be smoothly nitrated at room temperature by the combined action of nitrogen dioxide and molecular oxygen. The regioselectivity is considerably improved as compared with the conventional nitration methodology based on nitric and sulfuric acids. In some cases, the minor isomer became favoured to a significant extent, resulting in the reversal of ordinary isomer ratios of nitration products.

Naphthalene, 1- and 2-methylnaphthalenes were smoothly nitrated with nitrogen dioxide at low temperatures in the presence of ozone to afford the corresponding nitro derivatives in high yields.For naphthalene, the 1-nitro/2-nitro isomer ratios were remarkably high, mostly ranging from 35 to 70. 1,4-Dimethylnaphthalene suffered extensive side-chain substitution under similar conditions.The enhanced regioselectivity as compared with conventional nitrations has been interpreted in terms of the electron transfer mechanism involving the nitrogen trioxide as the initial electrophile.

A one-pot nitration of aromatic compounds by "claycop", a reagent consisting of an acidic montmorillonite clay impregnated with anhydrous cupric nitrate, is reported.Simply by varying the conditions, it is possible to drive the reaction at will toward either mono- or polynitration.Both the yields and selectivities are superior to those obtained under homogeneous reaction conditions.

1,5- AND 1,8-DINITRONAPHTHALENES ARE ISOLATED FROM MIXTURES OF ISOMETRIC DINITRONAPHTHALENES AT LEAST CONTAINING THE SAME. The mixture of isomers is treated successively with a more polar solvent and a less polar aromatic solvent for dinitronaphthalenes thereby dissolving the mixture of isomers except for 1,5-dinitronaphthalenes which remains largely undissolved in the more polar solvent. The residual mixture of isomers is subsequently treated, after removal of the more polar solvent, with a less polar aromatic solvent at elevated temperatures in which 1,8-dinitronaphthalenes remains as a largely insoluble residue.