Hydrogenation of anthracene

According to Sugino and Outi, the hydrogenation of anthracene to perhydroan-thracene over reduced copper catalyst proceeds through the intermediates shown in Scheme 11.18 the formation of these compounds depends on reaction temperatures.253... 

Scheme 3.1 Transfer-hydrogenation of anthracene with tetrahydronaphthalene as hydrogen source in molten SbCl3...

Z. G. Zhang, K. Okada, M. Yamamoto and T. Yoshida. Hydrogenation of anthracene over active carbon-supported nickel catalyst. Catalysis Today, 45, 361-366 (1998). 

Hydrogenation of anthracene (30) over Raney nickel, platinum or palladium also gives 9,10 dihydroanthracene (31) as the initial product but a rhodium catalyst gives the octahydro product, 32, in which both terminal rings are saturated (Eqn. 17.28). Further hydrogenation takes place under the conditions used to saturate alkylbenzenes with the predominant product the cis ring junction isomer. 

Shaw et al. [27] indicate that anthracene is more readily hydrogenated than other aromatic systems (e.g. naphthalene). The hydrogenation of anthracene can be described by the following equation (9.14) ... 

Polycyclic arenes are also hydrogenated in the presence of the monohydride catalyst, HCo(CO) (Equahon 15.101). The regioselectivity of this reduction is different from that of the hydrogenation of anthracene catalyzed by the ruthenium complex of Grey and Pez. This difference in regioselectivity results from a different mechanism. Halpem showed that the hydrogenation of polycyclic arenes catalyzed by HCo(CO) occurs by hydrogen atom transfer. ... 

SCHEME 13.26 Comparison of catalytic activities and selectivities of Rh on charcoal for the hydrogenation of anthracene (40). 

Nearly complete conversions and high selectivity toward the hydrogenated products without cracking or open ring-derived products (naphthenics) were achieved in the hydrogenation of anthracene with the previously mentioned carbon-supported Pd NPs nanomaterials [107]. 

Direct Hydrogenation. Direct hydrogenation of lignitic and other coals has been studied by many investigators. Lignite can be slurried with an anthracene-oil solvent, heated to a temperature of 460—500°C with 1 1 CO H2 synthesis gas at pressures to 28 MPa (280 atm) in a 2 kg/h reactor. The product hquids are separated, and in a commercial process, a suitable hydrogen-donor solvent would be recycled (54). 

Dealkylation, fragmentation, and hydrogenation of substituted polynuclear aromatics may also occur. The following is a representative example of hydrocracking of a substituted anthracene. 

In a dry, 1-1., two-necked flask, equipped with a mechanical stirrer and a reflux condenser fitted with a drying tube, are placed 17.8 g. (0.100 mole) of anthracene (Note 1), 27.2 g. (0.202 mole) of anhydrous cupric chloride (Note 2), and 500 ml. of carbon tetrachloride (Note 3). The reaction mixture is stirred and heated under reflux for 18-24 hours. The brown cupric chloride is gradually converted to white cuprous chloride, and hydrogen chloride is gradually evolved. At the end of the reaction the cuprous chloride is removed by filtration, and the carbon tetrachloride solution is passed through a 35-mm. chromatographic column filled with 200 g. of alumina (Note 4). The column is eluted with 400 ml. of carbon tetrachloride. The combined eluates are evaporated to dryness to give 19-21 g. (89-99%) of 9-chloroanthracene as a lemon-yellow solid, m.p. 102-104° (Note 5). Crystallization of the product from petroleum ether... 

It is, however, reasonable to assume that, in the case of closely similar reactions, that reaction leading to the most stable product will occur most easily. This hypothesis leads to a complete explanation of the observed courses of hydrogenation of benzene, naphthalene, and anthracene, which are represented by the following schemes, showing only the reactions for which data are available.5... 

Most often, these radicals are unstable and can exist only while adsorbed on the electrode, although in the case of polycyclic aromatic compounds (e.g., the derivatives of anthracene), they are more stable and can exist even in the solution. The radicals formed first can undergo a variety of chemical or electrochemical reactions. This reaction type is the analog of hydrogen evolution, where electron transfer as the first step produces an adsorbed hydrogen atom, which is also a radical-type product. 

The reactor was a 1 liter stainless steel rotating autoclave. In these experiments the ratio of anthracene oil to coal was 3 1. Coal (50 g) impregnated with catalyst (1% Sn as SnC ) was mixed with sand (200 g). The autoclave was pressurized with hydrogen to 10 MPa at room temperature and heated (ca 7°C/minute) to the final reaction temperature (450°C). The pressure at reaction temperature was approximately 25 MPa. 

Microautoclave data was also obtained with Wilsonville Batch I solvent utilizing Indiana V coal. Batch I solvent was obtained from Wilsonville in mid-1977. Other batches of recycle solvent were received later. Batch I solvent had inspections most like the Allied 24CA Creosote Oil used for start-up at the Wilsonville Pilot Plant. Succeeding batches of solvent received by CCDC showed substantial differences, presumably due to equilibration at various operating conditions. As the Wilsonville solvent aged and became more coal derived, the solvent aromaticity decreased with an increase in such compounds as indan and related homologs. The decrease in aromaticity has also been verified by NMR. A later solvent (Batch III) also showed an increase in phenolic and a decrease in phenanthrene (anthracene) and hydrogenated phenanthrene (anthracene) type compounds. 

In summary, the A1- and A2-dialin isomers have been shown to be appreciably more active than etralin (and decalin) in transferring hydrogen to anthracene and phenanthrene. The observed selectivity of this hydrogen transfer is in accord with the Woodward-Hoffman rules for group transfer reactions, anthracene conversions being in the ratio ( 3 / 0 ) = 12/1 >> 1 while phenanthrene conversions are in the ratio ( 0/(33 ) = 0.6/1 < 1. The quantitative differences in the selectivities observed with anthracene and phenanthrene are being further explored. 

At typical coal liquefaction conditions, namely temperatures from 300 to 400 C and reaction times on the order of 1 hr, hydrogen transfer from model CIO donors, the A1- and A2-dialins, to model C14 acceptors, anthracene and phenanthrene, occurs in the sense allowed by the Woodward-Hoffman rules for supra-supra group transfer reactions. Thus, in the conversion of the C14 substrates to their 9, 10 dihydro derivatives the dialins exhibited a striking reversal of donor activity, the A dialin causing about twice as much conversion of phenanthrene but only one-tenth as much conversion of anthracene as did A2-dialin. 

The complex [Rh(MeOH)2(diphos)]+ (diphos = l,2-bis(diphenylphosphino)eth-ane) has been reported to hydrogenate polynuclear aromatic hydrocarbons under mild conditions (60 °C, 1 bar H2) [17]. A kinetic study of the hydrogenation of 9-CF3CO-anthracene to the corresponding 1,2,3,4-tetrahydroanthracene was consistent with a rapid conversion of the precursor to [Rh( 76-anthracene)(diphos)]+ and a rate-determining step involving the reaction of the latter complex with H2... 

Endo and coworkers98 were able to catalyze the Diels-Alder reaction between acrolein and 1,3-cyclohexadiene by using a novel organic network material built up of anthracene-bisresorcinol derivatives which were held together by intermolecular hydrogen bonds. The suggested catalytic cycle was composed of sorption of the reactants in the cavities of the material, a pre-organized intracavity reaction, and desorption of the adduct. 

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