Yield Of Biphenyl Research Articles

The Role of Aroyloxyl Radicals in the Formation of Solvent-derived Products in Photodecomposition of Diaroyl Peroxides. The Reactivity of Substituted Cyclohexadienyl Radicals and Intermediacy of ipso Intermediates

Abstract Photolyses of bis(2-thiophenecarbonyl) peroxide (TPO) in benzene and toluene afforded, among free-radical products, biphenyl and dimethylbiphenyls, respectively, which were solely derived from the aromatic solvents. The yields of biphenyls depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations for their dimerization. Photolyses of TPO and dibenzoyl peroxide in 1,3,5-trimethylbenzene afforded also a solvent-derived product, 2,3′,4,5′,6-pentamethyldiphenylmethane. Its formation provides clear evidence for participation of cyclohexadienyl radicals bearing the aroyloxyl group on the methyl-substituted ipso carbon atom.

ChemInform Abstract: PHOTOLYSES OF BIS(2‐THIOPHENECARBONYL) AND BIS(3‐THIOPHENECARBONYL) PEROXIDES IN BENZENE. PRODUCTION OF BIPHENYL FROM THE SOLVENT BENZENE CONTROLLED BY THE PHOTOLYSIS RATE

Direct and sensitized photolyses of bis(2-thiophenecarbonyl) (2-TPO) and bis(3-thiophenecarbonyl) peroxide (3-TPO) in benzene afforded biphenyl derived solely from the solvent among the products. The yield of biphenyl depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations to dimerize.

REACTION OF DIMETHYL SULFITE WITH PHENYLLITHIUM. FORMATION OF BIPHENYL AND DIPHENYL SULFIDE VIA SULFURANE

Abstract Dimethyl sulfite reacted with an excess of phenyllithium yielding biphenyl and diphenyl sulfide in good yield. Other dialkyl sulfites also reacted giving identical yields of biphenyl and diphenyl sulfide irrespective of the structure of the aryl groups, indicating that dialkyl sulfites can be used for the reaction with aryllithiums in place of diaryl sulfoxides. The mechanism of the reaction of diaryl sulfoxides with aryllithium is discussed on the basis of the isomer distribution of bitolyls, the effect of additives, and the ratio of the benzyne and sulfonium salt pathways. Sulfurane 1 is formed in an initial stage of the reaction of diaryl sulfoxide with aryllithium followed by its competitive collapse by way of benzyne and sulfonium salt pathways.

PHOTOLYSES OF BIS(2-THIOPHENECARBONYL) AND BIS(3-THIOPHENECARBONYL) PEROXIDES IN BENZENE. PRODUCTION OF BIPHENYL FROM THE SOLVENT BENZENE CONTROLLED BY THE PHOTOLYSIS RATE

Abstract Direct and sensitized photolyses of bis(2-thiophenecarbonyl) (2-TPO) and bis(3-thiophenecarbonyl) peroxide (3-TPO) in benzene afforded biphenyl derived solely from the solvent among the products. The yield of biphenyl depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations to dimerize.

Supercritical-gas extraction of Turkish coking coal

Treatment of Zonguldak coal with toluene at 360 °C gave yields of extract which increased from 19–32% as the pressure of the extraction was increased from 11.6 to 29 M Pa. These yields were similar to those previously obtained by supercritical-gas extraction of lignites but the composition of the extracts differed. The lignite extracts contained a much higher proportion of petroleum ether-soluble material and only half the proportion of material insoluble in both petroleum ether and benzene than the Zonguldak coal extract. Benzene, biphenyl, naphthalene, phenanthrene, pyrene, benzoanthracene and be-nzophenanthrene nuclei were identified in the coal extract. Comparison of the yields of substituted benzenes with those obtained by low-temperature carbonization suggests that the proportions of different substitution pattern is determined by the structure of the fuel. Less naphthalene nuclei were found than expected but relatively large yields of biphenyls were obtained which were attributed to their formation from toluene in the presence of phenols.

Photo-oxygenations of bisphenylhydrazones, monophenylhydrazones, bishydrazones and monohydrazones of 1,2-diketones and related systems

Rose Bengal-sensitized photo-oxygenations of several bisphenylhydrazones of 1,2-diketones have been studied. The photo-oxygenation of benzil bisphenylhydrazone (9a) gave a mixture of products consisting of 2,4,5-triphenyl-1,2,3-triazole (10a, 27%), benzil (11a, 16%) benzoic acid (12, 33%) and biphenyl (13, 6%), whereas, biacetyl bisphenylhydrazone (9b), under analogous conditions gave a 2% yield of 4,5-dimethyl-2-phenyl-1,2,3-triazole (10b), a 30% yield of biacetyl monophenylhydrazone (16b) and a 1% yield of biphenyl. Cyclohexane-1,2-dione bisphenylhydrazone (9c) gave likewise, the corresponding triazole,10c (19%), cyclohexane-1,2-dione monophenylhydrazone (16c, 18%) and a small amount of biphenyl (13, 2%). Photo-oxygenation of acenaphthenequinone bisphenylhydrazone (9d) gave a mixture of products consisting of acenaphthenequinone monophenylhydrazone (16d, 67%), 1,8-naphthoic anhydride (23, 22%) and biphenyl (13, 9%). The photo-oxygenations of both benzil monophenylhydrazone (16a) and acenaphthenequinone monophenylhydrazone (16d) gave rise to products, similar to those obtained from9a and9d, respectively. Photo-oxygenation of 1,2-bisphenylazostilbene (18a) gave a 65% yield of the triazole10a, whereas, 2,3-bisphenylazo-2-butene (18b) gave a 16% yield of the triazole10b and a 5% yield of biphenyl. On the other hand, the photo-oxygenation of 1,2-bisphenylazocyclohexene (18c) gave a 77% yield of cyclohexane-1,2-dione (11c). The photo-oxygenation of 1,2-bisphenylazoacenaphthylene (18d) gave a 46% yield of acenaphthenequinone monophenylhydrazone (16d), a 51% yield of 1,8-naphthoic anhydride (23) and a 9% yield of biphenyl. The photo-oxygenations of both benzil bishydrazone (25) and benzil monohydrazone (27) have been studied. In the case of the former, a mixture of products consisting of a 28% yield of benzil (11a) and a 17% yield of benzoic acid have been isolated, whereas in the case of the latter, a 55% yield of benzoic acid was isolated as the sole product. Reasonable mechanisms have been suggested for the formation of the various products in the photo-oxygenations of the different substrates that we have examined.

Polymerization of aromatic nuclei. XVI. Mechanism of chain propagation in the polymerization of benzene by aluminum chloride–cupric chloride

AbstractA study was made of the mechanism of benzene polymerization by aluminum chloride‐cupric chloride. Our main effort was devoted to propagation with the aim of resolving a literature conflict as to whether a cationic or radical pathway is involved. When equimolar mixtures of benzene and haloarene are polymerized, the resulting copolymers are composed almost exclusively of benzene monomer. This approach is based on the known relative reactivities of the monomers toward electrophilic and radical species. The amount of haloaromatic present in the copolymer was determined by elemental analyses and confirmed by infrared spectroscopy. These results are strongly indicative of propagation by an electrophilic moiety. The presence of oxygen in the reaction mixture was found to have no significant effect on the rate or yield of the polymerization, in contrast to a previous published report. The progress of the reaction was followed by titration of the evolved hydrogen chloride. Phenyl radicals, obtained by the thermal decomposition of benzoyl peroxide in benzene, were found to be incapable of initiating the polymerization in the presence of cupric chloride. Increased yields of biphenyl and the presence of chlorobenzene point to oxidation of intermediate radicals by cupric chloride. None of the experimental evidence is satisfactorily interpreted by radical propagation. The data are nicely rationalized on the basis of cationic chain extension, apparently via a radical cation initiator.

PHOTOLYSIS AND RADIOLYSIS OF THE BENZENE‐FUMARONITRILE SYSTEM

Abstract— The photolytic and radiolytic product formation of the complex benzene‐fumaronitrile are compared. The equilibrium constants for the complexes of benzene‐fumaronitrile and benzene‐maleonitrile determined by UV and NMR spectroscopy are given. The products which were found in both photolysis and radiolysis of the system benzene‐fumaronitrile were biphenyl. phenylsuccinodinitrile and maleonitrile. The production of a 2:1 adduct of fumaronitrile and benzene in very small yields could only be confirmed in the case of photolysis. Additional products in radiolysis were phenylcyclohexadienes and benzonitrile. Experiments using filtered light proved that isomerisation of fumaronitrile to maleonitrile and production of phenylsuccinodinitrile proceed via the excited charge‐transfer complex. There are indications that the excited charge transfer complex is likewise an intermediate in the radiolytic formation of these nitriles. The addition of fumaronitrile to benzene reduces the yield of biphenyl in both photolysis and radiolysis.

Radiolysis of benzene + bromobenzene solutions

Yields of γ-ray radiolysis products from benzene, bromobenzene and solutions of benzene and bromobenzene have been measured. The yield of biphenyl was larger in the solutions than in either of the pure solvents. Rate constants for quenching reactions were estimated on the basis of the measured product spectra and the published value of the ratio of rate constants for quenching in benzene +p-terphenyl + bromobenzene solutions.

OXIDATIVE COUPLING OF AROMATIC COMPOUNDS WITH AN AQUEOUS PALLADIUM(II) SALT SOLUTION

Abstract The oxidative coupling of aromatic compounds was carried out between the organic phase containing an aromatic compound and the aqueous phase containing palladium(II) perchlorate-ferric perchlorate system as the catalyst. The yields of biphenyl and bitolyl per hour based on palladium charged were 350 and 1000 percent, respectively.

Synthesis of Biphenyl From Benzene in Microwave Low Pressure Discharge

AbstractIt is attempted to optimize biphenyl yields in 2450 MHz. discharges in pure benzene vapor in the pressure range of 1 to 20 torr. For a benzene throughput of 100 gm/hr. in a ½” tube and for 100 watts dissipated in the discharges the following results were obtained: benzene conversion 10%, biphenyl yield 50%, biphenyl energy yield 45 gm/kWhr. These values are compared with data from other workers and with our investigations in other cold or non-equilibrium discharge plasmas in benzene vapor.