- PROCESS FOR THE PRODUCTION OF A SULFONE MONOMER
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The present invention provides an economic and environmentally friendly method for the preparation of polymer grade 4,4'-dichlorodiphenyl sulfone which is substantially free of 2,4' and 3,4'-isomers of dichlorodiphenyl sulfone with yield of over 90%, with substantially reduced reaction times without the use of impregnated catalysts. Further no toxic byproducts such as dimethyl pyrosulfate are formed thereby reducing the load on effluent treatment with the added advantage of substantially recycling the reactants and byproducts. Further the present invention discloses a process is disclosed in which isomeric mixture of 4,4'-, 3,4'-, and 2,4'-dichlorodiphenyl sulfone produced during the preparation of 4,4'-dichlorodiphenyl sulfone is converted to value added products such as diphenyl sulfone, 2,4'- dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfone and 2-aminodiphenyl sulfone.
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Page/Page column 33
(2011/06/25)
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- Sulfonylation of aromatic compounds with sulfonic acids using silica gel-supported AlCl3 as a heterogeneous Lewis acid catalyst
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Silica gel-supported aluminum chloride (SiO2-AlCl3) has been shown to be a mild, efficient, and chemoselective heterogeneous Lewis acid catalyst for direct conversion of arenes to sulfones using sulfonic acids as sulfonylating agents. The catalyst can be prepared easily with cheap starting materials and is stable (as a bench-top catalyst) and reusable.
- Parvanak Boroujeni, Kaveh
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experimental part
p. 197 - 203
(2010/11/05)
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- Polystyrene supported Al(OTf)3: A stable, efficient, selective, and reusable catalyst for sulfonylation of arenes with sulfonic acids
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Cross-linked polystyrene supported aluminium triflate (Ps-Al(OTf) 3) was found to be an efficient and chemoselective heterogeneous Lewis acid catalyst for the direct conversion of arenes to sulfones using sulfonic acids as sulfonylating agents. The solid acid catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency.
- Boroujeni, Kaveh Parvanak
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experimental part
p. 1887 - 1890
(2010/11/18)
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- Highly selective catalytic Friedel-Crafts sulfonylation of aromatic compounds using a FeCl3-based ionic liquid
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Friedel-Crafts sulfonylation of aromatic compounds was carried out using FeCl3-based ionic liquid. These liquids serve as efficient media as well as Lewis acid catalyst.
- Bahrami, Kiumars,Khodei, Mohammad Mehdi,Shahbazi, Fomeida
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p. 3931 - 3934
(2008/09/21)
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- Method for acylation or sulphonylation of an aromatic compound
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The present invention relates to a process for the acylation or sulphonylation of an aromatic compound. More particularly, the invention relates to a process for the acylation or sulphonylation of an activated or deactivated aromatic compound. The invention is applied to the preparation of aromatic ketones or sulphones. The process for the acylation or sulphonylation of an aromatic compound which consists in reacting at least one aromatic compound with an acylating or sulphonylating agent, in the presence of a Friedel-Crafts catalyst is characterized in that the acylation or sulphonylation reaction is carried out in liquid phase under microwave irradiation.
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Page column 25-26
(2008/06/13)
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- An efficient method for aromatic Friedel-Crafts alkylation, acylation, benzoylation, and sulfonylation reactions
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Aromatic electrophilic substitution reactions such as alkylation, acylation, benzoylation, and sulfonylation were studied in the presence of a catalytic amount of Cu(OTf)2 and Sn(OTf)2. Cu(OTf)2 was very efficient for alkylation, acylation, and benzoylation reactions. However, in case of sulfonylation reactions, Sn(OTf)2 gave better results.
- Singh, Ravi P,Kamble, Rajesh M,Chandra, Kusum L,Saravanan,Singh, Vinod K
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p. 241 - 247
(2007/10/03)
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- Friedel-Crafts sulfonylation of aromatics catalysed by solid acids: An eco-friendly route for sulfone synthesis
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A mild and efficient catalytic method for Friedel-Crafts sulfonylation of arenes to the corresponding sulfones using a catalytic amount of reusable solid acid and arene- or alkanesulfonyl chlorides, sulfonic anhydrides and sulfonic acids as sulfonylating agents is described. Solid acids enable formation of a sulfone by the reaction of a sulfonic acid and an arene for the first time. In pursuit of the development of the best catalytic system, various metal-exchanged K10 montmorillonites and synthetic zeolites such as zeolite beta, zeolite Y and ZSM-5 have been screened for Friedel-Crafts sulfone synthesis. Fe3+-montmorillonite in the family of clays and zeolite beta in the family of zeolites exhibit higher activity. The activity is correlated to the presence of the right mix of Bronsted and Lewis acidic sites. The regioselective sulfonylation of toluene and naphthalene are studied in which para and beta selectivities are observed respectively. The Royal Society of Chemistry 2000.
- Choudary, Boyapati M.,Chowdari, N. Sreenivasa,Kantam, M. Lakshmi
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p. 2689 - 2693
(2007/10/03)
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- Halodediazoniations of dry arenediazonium o-benzenedisulfonimides in the presence or absence of an electron transfer catalyst. Easy general procedures to prepare aryl chlorides, bromides, and iodides
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The paper reports the results of a wide study aimed at preparing aryl chlorides 3 (19 examples), bromides 4 (19 examples), and iodides 5 (9 examples) by halodediazoniation of dry arenediazonium o-benzenedisulfonimides 1 with tetraalkylammonium halides 2. The reactions were carried out in anhydrous acetonitrile at room temperature (~20 °C) in the presence of copper powder and at 60 °C or room temperature without the catalyst. In optimal conditions the yields were from good to excellent (60 reactions, 61- 94% yield), with only a few exceptions (8 reactions, 51-55% yield). A good amount of the o-benzenedisulfonimide (7) was always recovered from the reactions and could then be reused to prepare salts 1. An interesting aspect of this research is the surprising role of the anion of o- benzenedisulfonimide (9) as an electron transfer agent.
- Barbero,Degani,Dughera,Fochi
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p. 3448 - 3453
(2007/10/03)
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- Bismuth(III) halides: Remarkable doping agents for triflic acid in the catalytic sulfonylation of arenes
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The catalytic activity of triflic acid has been dramatically increased by the addition of a catalytic amount of bismuth(III) chloride. Thus, the catalytic sulfonylation of arenes using the new system BiCl3-triflic acid has been successfully carried out while both components of this catalytic system are poorly active or inactive alone, which suggests a synergy between BiCl3 and triflic acid. Other bismuth halide-triflic acid systems proved to be active.
- Repichet,Le Roux,Dubac
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p. 9233 - 9234
(2007/10/03)
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- 1H and 13C NMR Study of Substituted Effects in 2- and 3-Substituted Diphenyl Sulphides and Sulphones and 4-Substituted 2',6'-Dimethyldiphenyl Sulphides
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The proton and carbon NMR spectra of nine 2-substituted diphenyl sulphides (S-2-X), seven 3-substituted diphenyl sulphides (S-3-X), nine 2-substituted diphenyl sulphones (SO2-2-X), nine 3-substituted diphenyl sulphones (SO2-3-X) and nine 4-substituted-2',6'-dimethyldiphenyl sulphides (Me2-S-4-X) were obtained.Correlations of the 1H and 13C chemical shifts were made with benzene substituent-induced chemical shifts (Lynch plots) and Hammett and dual-substituent parameters and the results were compared with those of 4-substituted diphenyl sulphides (S-4-X) and sulphones (SO2-4-X).The main conclusions are as follows: (i) the transmission of the substituent effects in substituted diphenyl sulphides decreases in the order S-4-X ca.S-2-X > Me2-S-4-X > S-3-X; (ii) the inductive effects are transmitted to a larger extent than the resonance effects to the unsubstituted ring in 3-substituted diphenyl sulphides, while the reverse trend is observed in other substituted diphenyl sulphides; (iii) in 2-methoxy-, 2-chloro-, 2-bromo- and 2-nitrodiphenyl sulphides, an increase in the size of the substituent causes an upfield shift for H-6 ascribable to the repulsion between the lone pairs of electrons on the sulphur and the substituent and its influence on the conformation; (iv) the diminished transmission of substituent effects to the remote rings in 4-substituted 2',6'-dimethyldiphenyl sulphides is probably due to the orthogonal orientation of the rings; and (v) the signal due to the H-6 of 2-substituted diphenyl sulphones suffers a downfield shift with an increase in the size of the substituent, this being ascribable to the increasing steric interaction between the 2-substituent and the sulphonyl oxygen and consequent changes in the conformation. - Keywords: NMR; 1H NMR; 13C NMR; diphenyl sulphides; diphenyl sulphones; ?-polarization
- Perumal, Subbu,Chandrasekaran, Ramasubbu,Vijayabaskar, Veerappan,Wilson, David A.
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p. 779 - 790
(2007/10/03)
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