305-80-6Relevant articles and documents
Ph-SO3H-modified mesoporous carbon as an efficient catalyst for the esterification of oleic acid
Geng, Liang,Yu, Gang,Wang, Yu,Zhu, Yuexiang
, p. 137 - 144 (2012)
Mesoporous carbon materials with thin pore walls (～1.7 nm) were synthesized using low-cost γ-Al2O3 as a hard template and in situ polymerized resorcinol-furfural resin as the carbon precursor. Compared with sugar, resin, a widely used carbon precursor, has higher carbon yield and simplifies the synthetic process. Ph-SO3H modified mesoporous carbon was synthesized by covalent grafting of Ph-SO 3H groups on mesoporous carbon via the diazonium salt. The resulting materials were characterized by means of nitrogen adsorption analysis, TEM, 13C NMR, XRD, FTIR and sulfur elemental analysis. The modified carbons were shown to possess high surface area (～1000 m2/g), a bimodal pore size distribution and high strong acid density (1.86 mmol H +/g). These sulfonated carbons were used as solid acid catalysts in the esterification of oleic acid and methanol, a key reaction in biodiesel production. Compared with the traditional solid acid Amberlyst-15, the optimized carbon catalyst exhibited much higher activity with a rate constant (1.34 h-1) three times to that of Amberlyt-15 and a turnover frequency (TOF) of 128 h-1 eight times that of Amberlyst-15. The efficient catalytic ability was attributed to the high surface area and a proper mesopore texture. This carbon catalyst could then be easily separated from the product by filtration. The catalyst was reused six times, and no distinct activity drop was observed after the initial deactivation.
Proton-Sponge-Like Superbases Built on the Benzo[h]quinoline Platform
Ozeryanskii, Valery A.,Pozharskii, Alexander F.
, p. 3298 - 3305 (2018)
6,10-Bis(dimethylamino)benzo[h]quinoline (6) and its “reverse” counterpart, the 6,7-isomer 7 (a “pyridine-extended” proton sponge), have been prepared in a three-step synthetic protocol starting from 1,5-bis- and 1,8-bis(dimethylamino)naphthalenes, respectively, through azo coupling and Skraup cyclisation reactions. These novel polyfunctional nitrogen bases demonstrate excellent chelation ability towards protons and even PdII, and behave as kinetically active (6) and kinetically inactive (7) compounds, as demonstrated by NMR transprotonation experiments in DMSO. Single-crystal X-ray diffractometry was used to characterise rare types of chelated [NHN]+ hydrogen bonds and to reveal the location of the proton in protonated 6 (H+ between NMe2 and the pyridine nitrogen) and its zwitterionic azo-dye precursor 8Z (H+ between NMe2 and the azo group). Experimental pKa values measured in DMSO show that 6 and 7 are strong bases, and the strength of the basicity of the 6,10-isomer 6 (pKa = 8.1) places this benzo[h]quinoline in the category of heterocyclic superbases.
Electrochemical and impedance spectroscopy studies of various diazonium salts on a glassy carbon electrode
Khoshroo, Maryam,Rostami, Abbas A.
, p. 841 - 846 (2010)
The derivatization of a glassy carbon electrode surface was achieved with and without electrochemical reduction of various diazonium salts in acetonitrile solutions. The surfaces were characterized, before and after their attachment, by cyclic voltammetry and electrochemical impedance spectroscopy to evidence the formation of a coating on the carbon surface. The results were indicative of the presence of substituted phenyl groups on the investigated surface. Also, the effects of diazonium thin films at the surface of a glassy carbon electrode, modification time, and salt concentration on their electrochemical responses in the presence of the Fe(CN)63-/4- probe were investigated. Electrochemical impedance measurements indicated that the kinetics of electron transfer is slowed down when the time and the concentration used to modify the glassy carbon electrode are increased. We therefore modified a glassy carbon surface via its derivatization with and without electrochemical reduction of various diazonium salts in acetonitrile solution. Springer-Verlag 2010.
Br?nsted acidic reduced graphene oxide as a sustainable carbocatalyst: A selective method for the synthesis of C-2-substituted benzimidazole
Karthik, Murugan,Suresh, Palaniswamy
, p. 17931 - 17938 (2018/11/21)
Br?nsted acidic reduced graphene acts as an efficient and sustainable carbocatalyst for the selective synthesis of C-2-substituted benzimidazoles under ambient conditions. A massive influx of sulphonic acid group on reduced graphene oxide surface gives graphene sulfonic acid (G-SO3H), which acts as a Br?nsted acidic catalyst for the synthesis of a series of benzimidazoles under mild conditions. The present methodology is a revamp of the benzimidazole synthesis with broad functional group tolerance in shorter time. G-SO3H provides an operationally simple, metal-free condition and is amenable to gram-scale production. Pyridine adsorption studies prove the catalytically responsible Br?nsted acidity of the catalyst. The catalyst is highly stable for several cycles without any loss of activity, which is evidenced by the FT-IR, PXRD and TEM characterization of the reused catalyst.
Synthesis and characterization of eight arylpentazoles
Ek, Stefan,Rehn, Stanley,Wahlstroem, Larisa Yudina,Oestmark, Henric
, p. 261 - 267 (2013/07/05)
p-Nitrophenyl-, p-methoxyphenyl-, p-hydroxyphenyl-, p-t-butylphenyl-, p-HOSO2-phenyl-, 15N-p-N,N-dimethylaminophenyl-, 15N2-p-N,N-dimethylaminophenyl-, and dicyanoimidazopentazole were obtained via different synthetic routes. Cesium, barium, potassium, and sodium salts of the arylpentazoles bearing acidic hydrogens were prepared. NMR spectra (1H, 13C) are reported for the arylpentazoles, their corresponding arylazides, and their salts.
Conversion of fructose into 5-hydroxymethylfurfural and alkyl levulinates catalyzed by sulfonic acid-functionalized carbon materials
Liu, Ruliang,Chen, Jinzhu,Huang, Xing,Chen, Limin,Ma, Longlong,Li, Xinjun
supporting information, p. 2895 - 2903 (2013/10/08)
A series of sulfonic acid-functionalized carbon materials (C-SO 3H), including poly(p-styrenesulfonic acid)-grafted carbon nanotubes (CNT-PSSA), poly(p-styrenesulfonic acid)-grafted carbon nanofibers (CNF-PSSA), benzenesulfonic acid-grafted CMK-5 (CMK-5-BSA), and benzenesulfonic acid-grafted carbon nanotubes (CNT-BSA), have been studied for fructose dehydration to 5-hydroxymethylfurfural (HMF) and fructose alcoholysis to alkyl levulinate. A study for optimizing the reaction conditions such as the catalyst loading, the reaction time, and the temperature has been performed. Under the optimal conditions, high HMF and ethyl levulinate yields of up to 89% and 86%, respectively, are obtained. The catalytic activities of C-SO3H for the conversions of fructose into both HMF and ethyl levulinate follow the order of their acid strength. The relationship between the catalytic activity and acid density of C-SO3H shows a linear correspondence in the fructose dehydration to HMF. The facile separation, ease of recovery, and high thermal stability make the developed C-SO3H efficient and environment-friendly catalytic materials for transforming biomass carbohydrate into fine chemicals.
Modification of activated carbons based on diazonium ions in situ produced from aminobenzene organic acid without addition of other acid
Lebegue, Estelle,Madec, Lenaic,Brousse, Thierry,Gaubicher, Joel,Levillain, Eric,Cougnon, Charles
supporting information; experimental part, p. 12221 - 12223 (2011/12/16)
Activated carbon products modified with a benzene sulfonic acid group were prepared based on the spontaneous reduction of diazonium salts in situ generated in water without addition of an external acid. The diazotization reaction assisted by the organic acid substituent, produced at once amine, diazonium and triazene functionalities that maximize the grafting yield by a chemical cooperation effect.
Sulfonated ordered nanoporous carbon (CMK-5-SO3H) as an efficient and highly recyclable catalyst for the silylation of alcohols and phenols with hexamethyldisilazane (HMDS)
Zareyee, Daryoush,Ghandali, Mohammad S.,Khalilzadeh, Mohammad A.
experimental part, p. 1521 - 1525 (2012/06/18)
An environmentally friendly catalytic system for trimethylsilylation of alcohols and phenols with hexamethyldisilazane can be successfully carried out for the first time over sulfonated mesoporous carbon catalyst (CMK-5-SO 3H) in dichloromethane at ambient temperature and excellent conversions were obtained. Furthermore, the catalyst displays high activity and thermal stability (to 200 °C) and it can be reused repeatedly for at least 25 cycles without any evidence of loss of activity, confirming the stability of covalent bonding of acidic centers.
Thrombopoietin mimetics
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Page column 19, (2008/06/13)
Non-peptide TPO mimetics are disclosed, as well as a method of treating thrombocytopenia, in a mammal, including a human, in need thereof, which comprises administering to such mammal an effective amount of a selected hydroxy-1-azo-naphthalene derivative.
Waste-free chemistry of diazonium salts and benign separation of coupling products in solid salt reactions
Kaupp, Gerd,Herrmann, Andreas,Schmeyers, Jens
, p. 1395 - 1406 (2007/10/03)
Gas-solid and solid-solid techniques allow for waste-free and quantitative syntheses in the chemistry of diazonium salts. Five techniques for diazotations with the reactive gases NO2, NO and NOCl are studied. Two types are mechanistically investigated with atomic force microscopy (AFM) and are interpreted on the basis of known crystal packings. The same principles apply to the cascade reactions that had been derived from one-step reactions. Solid diazonium salts couple quantitatively with solid diphenylamine and anilines to give the triazenes. Azo couplings are achieved with quantitative yields by cautious co-grinding of solid diazonium salts with β-naphthol and C-H acidic heterocycles, such as barbituric acids or pyrazolinones. Solid diazonium salts may be more easily applied in a stoichiometric ratio for couplings in solution. Co-grinding of solid diazonium salts with KI gives quantitative yields of various solid aryl iodides. The unavoidable coupling products in salt reactions are completely separated from the insoluble products in a highly benign manner. The solid-state reactions compare favourably with similar solution reactions that produce much waste. The structures of the products are elucidated with IR and NMR spectroscopy and mass spectrometry, while the tautomeric properties of the compounds are studied with density functional calculations at the B3LYP/6-31G* and BLYP/6-31G** levels.
