Naphthalene production figures

Naphthalene derivatives are of diverse importance as intermediates for agricultural, constmction, pharmaceutical, photographic, mbber, tanning, and textile chemicals. In this article production figures, economics, and processes are discussed for most commercially important compounds. Sources for a more comprehensive study of naphthalene derivatives are available (1 8). 

Primary intermediates were originally manufactured within the dyes industry. All the significant primaries, about 30 different products, are derived from ben2ene, toluene, or naphthalene. Actual production figures for primaries are not readily available, and in any event the amounts used within the dyes industry are variable. The primaries are Hsted here with a reference to the Eniyclopedia article that covers them in detail including production and consumption figures. 

For example, the solvent products of a liquefaction carried out with a synthetic solvent (80% 2-methyl naphthalene, 18% p-cresol and 2% y-picoline) were shown (by gc/ms) to have formed a variety of dimeric products Figure 7 presents the gas chromatogram of this solvent after reaction in which the major components were identified ... 

The GC analysis results of the liquid product (Figure 23.8) were focused on styrene, benzene, toluene, and naphthalene components, the often quoted compounds in polystyrene degradation [33, 51, 62-64,]. The run at 750°C showed 48% benzene, 18% styrene, 8% toluene. The benzene content decreased steadily with increasing operating temperatme. 

The pyrolytic studies on meteorites are commonly done at different temperatures. A preheating step is utilized to insure that any possible adsorbed gases on the surface of the meteorite from the terrestrial environment are eliminated. Several organic compounds are monitored in pyrolysates such as polycyclic aromatic compounds. As an example, the results on naphthalene production upon pyrolysis from several carbonaceous chondrites, normalized by the total carbon content before pyrolysis, are shown in Figure 17.2.1 [76],... 

Figure 17.2.1. Naphthalene production upon pyrolysis from several carbonaceous chondrites [76] reported to total carbon.

The Bureau of Mines is a source of many chemical statistics. The monthly Coke and Coal Chemicals report, part of the bureau s Mineral Industry Surveys, contains, in addition to data on oven and beehive coke production, figures on production of ammonium sulfate, ammonia liquor, naphthalene, benzene, toluene, xylene, solvent naphtha, pyridine, crude coal tar, and cresote oil. Sales and end-of-month stock figures are also shown in the report. A useful feature of the report is the year-end supplement which gives year s totals by months. 

In 1968 U.S. production of p- and o-xylene was estimated at 1.3 billion and 0.97 billion pounds per year respectively. Production figures for m-xylene have never been published by the Tariff Commission. Its use has, however, remained quite small in relation to p- and o-xylene. It is expected that domestic demand for both p- and o-xylene will continue to increase. Terephthalic acid is the key component required for production of polyester film and fibers and is presently produced only from p-xylene. Phthalic anhydride is produced from both naphthalene and o-xylene. Although o-xylene is not expected to replace naphthalene entirely, its use for phthalic anhydride manufacture is expected to increase. 

Figure 9.3 shows the flow-sheet for the hydrogenation of coal tar-derived naphthalene (Unionfining) the naphthalene product can be further purified by crystallization or distillation. 

The Sulzer-MWB and the Brodie crystallization processes are most commonly used to recover naphthalene by crystallization. Figure 9.5 shows the Sulzer-MWB flow sheet, which is operated in a modified form in plants with a naphthalene production of up to 60,000 tpa. 

Generally, the sulfonation of naphthalene leads to a mixture of products. Naphthalene sulfonation at less than ca 100°C is kineticaHy controlled and produces predominandy 1-naphthalenesulfonic acid (4). Sulfonation of naphthalene at above ca 150°C provides thermodynamic control of the reaction and 2-naphthalenesulfonic acid as the main product. Reaction conditions for the sulfonation of naphthalene to yield desired products are given in Figure 1 alternative paths are possible. A Hst of naphthalenesulfonic acids and some of their properties is given in Table 1. 

Figure 22-8 shows the features of a horizontal center-fed column [Brodie, Au.st. Mech. Chem. Eng. Tran.s., 37 (May 1979)] which has been commercialized for continuous purification of naphthalene and p-dichlorobenzene. Liquid feed enters the column between the hot purifying section and the cold freezing or recovery zone. Ciystals are formed internally by indirect cooling of the melt through the walls of the refining and recovery zones. Residue liquid that has been depleted or product exits from the coldest section of the column. A spiral conveyor controls the transport of solids through the unit. 

Simple aromatic hydrocarbons come from two main sources coal and petroleum. Coal is an enormously complex mixture made up primarily of large arrays of benzene-like rings joined together. Thermal breakdown of coal occurs when it is heated to 1000 °C in the absence of air, and a mixture of volatile products called coal for boils off. Fractional distillation of coal tar yields benzene, toluene, xylene (dimethylbenzene), naphthalene, and a host of other aromatic compounds (Figure 15.1). 

Figure 4.48 Product spectra and isomer ratios for the nitration of naphthalene with HNOj in micro reactors from different suppliers [98],...

The following reasoning was used to eliminate the less probable mechanisms shown in Figure 4. A H atom is added to naphthalene to form an a-radical in reaction 1A and a /3-radical in reaction IB. Both are resonance-stabilized radicals. They can lose either a 2H atom or a H atom to regenerate naphthalene. We have shown a 2H atom lost to form a protium-enriched product in reactions 1A and IB. The fact that we observe a fourfold increase of protium in the a-position of spent naphthalene suggests that reaction IB is faster than reaction 1A and, therefore, is the predominant mechanism. 

In the present estimation, a continuous dehydrogenation reactor in which decalin is supplied to the catalyst at various feed rates without internal refluxing is assumed. Here all the condensable products and unconverted decalin were removed from the reactor to the condensation part (see Figure 13.22). Now, the stationary rates of hydrogen generation (VH), naphthalene formation (VN), and evaporation of unconverted decalin (VD) are defined as the magnitudes per area of the catalyst layer (mol/m2h). All these rates are expressed from mass balance as follows . 

The suitability of ethers derived from 1,4-dihydroxy-1,2,3,4-tetrahydro-naphthalene (DHTN) in the design of polymers susceptible to catalyzed thermolytic cleavage is demonstrated by the behavior of its bis-p-nitrophenyl ether derivative upon treatment by a trace of acid. Figure 2, curve A, shows the H-NMR spectrum of the starting compound, while curve B shows the product which is obtained upon addition of triflic acid. It is readily seen from these spectra that quantitative cleavage into naphthalene and p-nitrophenol is obtained as elimination occurs easily to afford the aromatic product. The driving force in this reaction is the facile aroma-tization which produces naphthalene. 

Nitroarenes were formed under laboratory conditions when PAH reacted with gas-phase OH radical (in presence of NO ) and N2O540 45. The atmospheric nitroarene formation rate depends upon the concentration of the individual species N2O5-NO3-NO2 An analogous reaction sequence occurs when PAH reacts in N2O5-NO3-NO2 systems46. Naphthalene reacts with NO3 radical forms NO3-naphthalene adduct, which dissociates or reacts with NO2 to form nitronaphthalene and other products as shown in Figure 6. 

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