Xylene nitration product

Nitrated Solvent Naphtha (N.S.N.). As nitration of crude solvent naphtha by the usual one-stage method results in yields that are too low, because of oxidation, E. Blecher et al (Ref 3) proposed nitrating only the refined material, and in two stages. The two-stage method is described in Colver, pp 255 686—87 (Ref 4). The product consists chiefly of 2,4,6-Trinitro-mesitylene (see under Mesitylene and Deriva- tives in this Vol), and 3,5,6-trinitropseudocumene, with small quantities of the nitrated products of xylene, ethylbenzene, etc... 

The 2- isomer predominates in the nitration product, while the 2,5- isomer formed in the nitration of 5-nitro-m-xylene is obtained only in small quantity. 

According to Soviet data (Kravchinskii [3]), from the fraction of commercial xylene boiling below 136.5°C a nitration product of low value is obtained, melting... 

The nitration products of toluene and xylene are oxidized to the corresponding acids and the dinitrobenzene is extracted, after alkalization, with petroleum ether. The solvent is evaporated off and the residue is transferred into a carbonate-containing supporting electrolyte containing 50 per cent ethanol. 

Group 1 Benzene, all ASTM grades Toluene, all ASTM grades Xylene, nitration grade Xylene, 5° Xylene, 10° Any other more highly refined products 96 15... 

Nitration of 1 4 dimethylbenzene (p-xylene) gives a single prod uct having the molecular formula C8H9NO2 m high yield What is this product... 

Approximately 45% of the world s phthaUc anhydride production is by partial oxidation of 0-xylene or naphthalene ia tubular fixed-bed reactors. Approximately 15,000 tubes of 25-mm dia would be used ia a 31,000 t/yr reactor. Nitrate salts at 375—410°C are circulated from steam generators to maintain reaction temperatures. The resultant steam can be used for gas compression and distillation as one step ia reduciag process energy requirements (100). 

The mono- and dinitro products have no musk odour, and therefore the nitration of the hydrocarbon should be carried as far as possible. The constitution of this artificial musk, or " xylene musk as it is often called, is probablv—... 

Production of p-xylene via p-xylene removal, i.e., by crystallization or adsorption, and re-equilibration of the para-depleted stream requires recycle operation. Ethylbenzene in the feed must therefore be converted to lower or higher boiling products during the xylene isomerization step, otherwise it would build up in the recycle stream. With dual-functional catalysts, ethylbenzene is converted partly to xylenes and is partly hydrocracked. With mono-functional acid ZSM-5, ethylbenzene is converted at low temperature via transalkylation, and at higher temperature via transalkylation and dealkylation. In both cases, benzene of nitration grade purity is produced as a valuable by-product. 

Major products reported from the photooxidation of o-xylene with nitrogen oxides include formaldehyde, acetaldehyde, peroxyacetyl nitrate, glyoxal, and methylglyoxal (Altshuller, 1983). The rate constant for the reaction of o-xylene and OH radicals at room temperature was 1.53 x 10 " cmVmolecule-sec (Hansen et al, 1975). A rate constant of 8.4 x 10 L/molecule-sec was reported for the reaction of o-xylene with OH radicals in the gas phase (Darnall et al., 1976). Similarly, a room temperature rate constant of 1.34 x 10 " cmVmolecule-sec was reported for the vapor-phase reaction of o-xylene with OH radicals (Atkinson, 1985). At 25 °C, a rate constant of 1.25 X 10 " cmVmolecule-sec was reported for the same reaction (Ohta and Ohyama, 1985). 

Chemical/Physical. Under atmospheric conditions, the gas-phase reaction of o-xylene with OH radicals and nitrogen oxides resulted in the formation of o-tolualdehyde, o-methylbenzyl nitrate, nitro-o-xylenes, 2,3-and 3,4-dimethylphenol (Atkinson, 1990). Kanno et al. (1982) studied the aqueous reaction of o-xylene and other aromatic hydrocarbons (benzene, toluene, w and p-xylene, and naphthalene) with hypochlorous acid in the presence of ammonium ion. They reported that the aromatic ring was not chlorinated as expected but was cleaved by chloramine forming cyanogen chloride. The amount of cyanogen chloride formed increased at lower pHs (Kanno et al., 1982). In the gas phase, o-xylene reacted with nitrate radicals in purified air forming the following products 5-nitro-2-methyltoluene and 6-nitro-2-methyltoluene, o-methylbenzaldehyde, and an aryl nitrate (Chiodini et ah, 1993). 

The historical development of aromatics production from petroleum is outlined, and the methods employed during World War II for the production of nitration grade toluene are described. Included is a discussion of methods of synthesizing and purifying benzene, xylenes, and aromatics of higher molecular weight both as mixtures and as pure compounds. Data are presented on the composition of the aromatic hydrocarbons available from typical hydroformates. Aromatics and mixtures thereof currently available from petroleum are listed. Some of the problems facing the industry in the field of aromatics production are discussed and the probable trend of future research is indicated. 

T he petroleum industry entered the field of aromatics production largely because the unprecedented demand for toluene for the manufacture of TNT at the outbreak of World War II in 1939 could not be met by other sources. As a result of its efforts, the industry supplied 75 to 85% of all the toluene which was nitrated for TNT production during the latter years of World War II. Since that time the petroleum refiners have remained in the field and at present they are major suppliers of toluene and xylenes. In Table I it is shown that in 1949 about 59% of the toluene and 84% of the xylenes produced in the United States were derived from petroleum sources. The petroleum industry has diversified its operations in the field of aromatics production until at present a variety of materials is offered. Table II presents a partial list of the commercially available aromatics, together with some of their uses. A number of other aromatics, such as methylethyl-benzene and trimethylbenzene, have been separated in small scale lots both as mixtures and as pure compounds. 

Given this behavior (little selectivity in distinguishing between different substrate molecules), the selectivity relationship would predict that positional selectivity should also be very small. However, it is not. For example, under conditions where nitration of p-xylene and 1,2,4-trimethylbenzene takes place at about equal rates, there was no corresponding lack of selectivity at positions within the latter.83 Though steric effects are about the same at both positions, more than 10 times as much 5-nitro product was formed as 6-nitro product. 

N 17.90% expl oil, impact sensitive was prepd by DuPont by condensing Trinitro-m-Xylene with HCHO and nitrating the product Ref Blatt, OSRD 2014(1944)... 

Dinitro-l, 2-dime tbylbenzene, ndls (from ale), mp 56—60° 89—90° obtd with other products on nitrating o-xylene or 3-nitro-o-xylene with coned nitric acid (Ref 1, p369 Ref 2, pl8l)... 

Dinitro-l, 4-dime tbylbenzene, monoclinic prisms (from ale or benz), mp 90—93° obtd with other products on nitrating p-xylene with coned nitric acid or with mixed acid (Ref 1, p387 Ref 2, pl88 Ref 3, p302 ... 

M. Warman, Preparation of Trinitro-Meta-Xylene (TNX) , PATM 1728 (1966) [Reported is a procedure for the pilot plant prepn of TNX from m-xylene. The nitration of m-xylene is carried out in two stages 1) The conversion of m-xylene to 2-nitro-m-xylene using mixed add (sulfuric 59/nitric 25/w 16%) at 35 to 50°, and 2) The trinitration of 2-nitro-m-xylene to trinitro-m-xylene, again using mixed add (sulfuric 79/nitric 17.5/w 3.5%), at 95 to 102°. The author states that the overall yield of TNX from m-xylene is as high as 94%. One crystn of the crude product from acet is sufficient to raise the mp to the 182-83° value reported in the literature]... 

C10H9N4O12 mw 391.24 N 17.90% OB to C02 -51.12% oil. Prepn is by condensing trinitro-m-xylene with formaldehyde, and nitrating the product. The compd can be detond with a hammer blow... 

Nitroxylenes are especially important because 4-amino-o-xylene (xylidine), formed from 4-nitro-o-xylene (4-o-NX) upon reduction, is used as a starting material for the production of riboflavin. Nitration of o-xylene by the conventional mixed acid method gives a mixture of 4-o-NX 31-55% and 3-o-NX 45-69 %. 

Nitration of o-xylene with N02 has been performed in the gas phase over several zeolites (HBeta, HY, HZSM-5 and HMordenite), as well as on sulfuric acid supported on silica and sulfated zirconia at temperatures between 50 and 130°C.[72] HBeta was found the most active and selective catalyst for the production of 4-o-NX giving ratios of 4-o-NX 3-o-NX as high as 6 1, whereas no dinitro-o-xylene compounds were detected. 

In both syntheses the benzoxazole synthon 176 was prepared from methyl 5-hydroxyanthranilate (177), the amino group of which was trifluoroacetylated to give 178. Nitration of 178 gave the 6-nitro derivative 179 as the major product (in a 2 1 mixture with the 4-nitro compound) catalytic reduction to the 6-amino-5-hydroxy compound 180 was followed by refluxing with acetyl chloride in xylene to afford the benzoxazole 181, N-methylation of which yielded 176, the overall yield from 177 being 60% (94). 

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