Dibenzothiophenes derivatives

Separation of dibenzothiophene derivatives from petroleum oil fractions has been achieved by integrated approaches in which fractionating processes such as isothermal distillation, vacuum fractionation, and molecular distillation have been combined with spectroscopic methods including mass spectrometry and NMR spectroscopy. " Dibenzothiophenes have also been concentrated in sharp chromatographic fractions obtained, for example, by, alumina gel percolation, and have been detected by gas chromatography. Gas chromatography has also been used to... 

Although the mass spectra of dibenzothiophene, its sulfoxide, and its sulfone have been recorded, the bulk of published work in this area is mainly of a general nature concerned with the identification of types and classes of sulfur compounds. As a result, detailed fragmentation patterns of dibenzothiophene derivatives are few in number. Mass spectrometry, particularly low electron voltage mass spectrometry, has, however, been extensively used for the identification of dibenzothio-phenes in petroleum. ... 

Dibenzothiophene derivatives have been used as co-catalysts in the addition polymerization of vinyl and diene monomers. Dibenzothiophene itself, in conjunction with vanadium oxychloride, is effective in initiating the polymerization of isobutylene, - although when incorporated in a Ziegler catalyst system, competition between donor and monomer for the most electrophilic sites results in deactivation of the catalyst. Despite the fact that 2-vinyl- - - and 4-vinyldibenzothiophene - readily undergo thermal polymerization,... 

In describing catalytic activities and selectivities and the inhibition phenomenon, we will use a common format, where possible, which is based on a common reaction pathway scheme as outlined in Scheme 1. In contrast to the simple one- and two-ring sulfur species from which direct sulfur extrusion is rather facile, in the HDS of multiring aromatic sulfur compounds such as dibenzothiophene derivatives, the observed products are often produced via more than one reaction pathway. We will not discuss the pathways that are specific for thiophene and benzothiophene as this is well represented in the literature (7, 5, 8, 9) and, in any event, they are not pertinent to the reaction pathways involved in deep HDS processes whereby all of the highly reactive sulfur compounds have already been completely converted. 

Dibenzothiophene derivatives are available from benzo[Z> jthiophenes by this procedure. In this case the major product of Friedel-Crafts acylation is the 3-substituted derivative cf. Chapter 3.14) and reaction of succinic anhydride gives as the major product the keto acid (319), which is then reduced and cyclized via the acid chloride to 4-keto-l,2,3,4-tetrahydrodibenzothiophene (320). Better yields were obtained when 3-methoxycar-bonylpropionyl chloride was substituted for succinic anhydride in the first step (69JHC771). 

Alkyl- or aryl-dibenzothiophenes are conveniently prepared from the 2-arylthio-cyclohexanones, which are readily cyclized and dehydrogenated to yield the respective 1-, 2-, 3- or 4-substituted dibenzothiophenes (382 equation 9 Section 3.15.2.3.2). More complex polycyclic systems are available, using suitable aryenethiols, such as naph-thalenethiols, and 2-bromo-l-tetralone to synthesize the appropriate 2-arylthio ketones. Diaryl sulfides can be converted to dibenzothiophene derivatives in satisfactory yields by photolysis in the presence of iodine (equation 10) (75S532). Several alkyldibenzothiophenes with substituents in the 2- and/or 3-positions were prepared in satisfactory yield by the condensation of dichloromethyl methyl ether with substituted allylbenzo[6]thiophenes (equation 11) (74JCS(P1)1744). 

The sulfur-heterocyclic compounds in the mid-distillate range are primarily the thiacyclane derivatives, benzothiophene derivatives and dibenzothiophene derivatives. with lesser amounts dialkyl-, diaryl- and aryl-alkyl sulfides. Sulfur compounds are significant contributors to the vacuum gas oil fraction (Ma et al., 1997). The major sulfur species are alkyl benzothiophene derivatives, dibenzo-... 

The additional rejected claims, 2-8, were directed to additional, presumably narrower embodiments of claim 1. In rejecting claims 1-8 for alleged obviousness, the USPTO examiner (and majority of the USPTO Board that upheld the rejection) relied on a single piece of prior art from the chemical literature.26 The cited art related to a study of the local anesthetic properties of certain carbazoles, dibenzofurans, and dibenzothiophene derivatives. There were no bis-basic esters of carbazoles disclosed (only mono-basic esters), but there was one bis-basic ester of a dibenzofuran that was disclosed, having the structure shown in Figure 8.2. 

Furthermore, the thianthrene 5-oxides (57), substituted or not, react with n-butyllithium or phenyllithium to provide various dibenzothiophene derivatives (58) and diaryl sulfides (59) (Equation (7)) <91H(32)675>. 

Microbes are effective in converting organic sulfur compounds such as thiophene derivatives and dibenzothiophene derivatives. Organics sulfur ranoval is in the neighborhood of 25% (there are claims of higher ranoval of sulfur) and the combined use of microbes, either simultaneously or sequentially, could potentially improve organic sulfur rejection. The limiting factors appear to be those of accessibility and residence time. Therefore, finer size coal should be used not only to improve accessibility of microbes to coal particle surfaces but also to reduce the overall retention time in the bioreactor. 

Activation of carbon—hydrogen bonds in benzyl phenyl sulfoxides catalysed by palladium may lead to dibenzothiophene derivatives (39). lodoarenes and silver salts are required as additives, and product formation requires several consecutive catalytic cycles. The copper-catalysed conversion of bisaryloxime ethers to 2-arylbenzoxazoles is likely to involve complexation of the catalyst at... 

Reaction at Sulphur.— The kinetics of the oxidation of benzo[/>]thiophen and its 3-substituted derivatives by perbenzoic acid in dichloromethane at 30 °C have been studied. The rate constants obtained for the first step, the oxidation to the sulphoxide, have been correlated with values, whereas the rate constants for the second step, of oxidation to the sulphone, have been correlated with values. A number of benzo[ft]thiophen and dibenzothiophen derivatives and their sulphoxides have been S- and O-alkylated, respectively, with silver perchlorate and alkyl halides. 5-Methoxydibenzothiophenium perchlorate reacted with amines to give 5-aminosulphonium salts, and with certain carbanions to give zwitterionic compounds such as (394). 

With respect to the increasing demand for practically S-free fuels (<10ppm), S-species with a very low reactivity like dibenzothiophene derivatives have to be converted (Figure 6.8.6), typically in a second deep HDS step, which leads to additional high investment and operating costs. The enormous expenses needed today for such a deep HDS of already hydrotreated (pre-desulfurized) diesel oil can be illustrated by typical industrial data [MiRO-refinery 2004 (oral communication) Wache et al. (2006)] Deep HDS reactors have a volume of up to 500 m to treat about 400 of oil per h. The feed rate of fresh H2 is about 40 m (NTP) per m oil, the recycle rate is about three, and for a typical pressure of 6 MPa the pressure drop of about 1 MPa has to be compensated by a huge recycle compressor (1 MW). 

Although 37 is an example of an aromatic S -nitrosothiol, and S -nitrosothiols are recognized to be less stable than aliphatic derivatives, 37 showed much higher thermal stability than observed early for 5-nitrosothiols. Even after heating in benzene-fig at 80°C for 60 hr, 38% of 37 remained unchanged the remainder of 37 was converted to the dibenzothiophene derivative 38 and thiol 36 (Scheme 11.20). In this reaction, no formation of the corresponding disulfide 39 was observed. 

Carbazoles, dibenzofurans, and dibenzothiophene derivatives 10 have been obtained via photocyclization of the corresponding diphenylamine, diphenylether, or diphenylthioether precursors 9 (Scheme 3). In these reactions, the lone pair of heteroatoms contributes to the 6jr—electrons engaged in the electro-cyclization. The re-aromatization occurred under oxidative conditions in the presence of oxygen or iodine. When irradiated in acetonitrile solution containing aqueous HCl, compounds 11 were transformed into... 

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