- Synthesis of new sterically hindered anilines
-
Ring-alkylated primary, secondary and tertiary anilines have been ethylated with ethylene at benzylic positions in a simple and inexpensive one-pot procedure which is mediated by the use of the superbase system nBuLi/LiK(OCH2CH2NMe2)2 in the presence of Mg(OCH2CH2OEt)2. Primary and secondary anilines are ethylated readily at ortho-benzylic positions but with difficulty or not at all at other positions. Tertiary anilines are ethylated at all positions. Mono- or diethylation occurs depending on the steric constraints present. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Steele, Barry R.,Georgakopoulos, Spyros,Micha-Screttas, Maria,Screttas, Constantinos G.
-
-
Read Online
- Effect of Zr on catalytic performance of unsupported Ni(Zr)Mo and Ni(Zr)W sulfide catalysts for quinoline hydrodenitrogenation
-
To increase the dispersion of active species and full utilization of active metals are of great importance for hydrodenitrogenation (HDN) performance of unsupported hydrotreating catalysts. Herein, a series of unsupported Ni(Zr)MoS and Ni(Zr)WS catalysts were prepared from Ni(Zr) layered double hydroxide (LDH) precursors. The Zr species remarkably promote the dispersion and reducibility of NiMo and NiW composite species. Also, the total HDN rate constants are increased from 2.42 h?1 to 9.18 h?1 for Ni(Zr)MoS and from 5.68 h?1 to 23.0 h?1 for Ni(Zr)WS, and exhibit a maximum at a Zr/Ni atomic ratio of about 0.04. The HDN selectivities indicate that the Zr species increase the number of superficial active sites without affecting their structure. The present work shows that the crystallinity of LDH precursors is crucial to the structure of unsupported sulfide catalysts, and a suitable amount of Zr could be a dispersive promoter to increase the HDN activity.
- Jiang, Zongxuan,Li, Can,Liu, Tiefeng,Liu, Xinyi,Zhang, Cen
-
-
- Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface
-
Dehydrogenative aromatization is one of the attractive alternative methods for directly synthesizing primary anilines from NH3 and cyclohexanones. However, the selective synthesis of primary anilines is quite difficult because the desired primary aniline products and the cyclohexanone substrates readily undergo condensation affording the corresponding imines (i.e., N-cyclohexylidene-anilines), followed by hydrogenation to produce N-cyclohexylanilines as the major products. In this study, primary anilines were selectively synthesized in the presence of supported Pd nanoparticle catalysts (e.g., Pd/HAP, HAP=hydroxyapatite, Ca10(PO4)6(OH)2) by utilizing competitive adsorption unique to heterogeneous catalysis; in other words, when styrene was used as a hydrogen acceptor, which preferentially adsorbs on the Pd nanoparticle surface in the presence of N-cyclohexylidene-anilines, various structurally diverse primary anilines were selectively synthesized from readily accessible NH3 and cyclohexanones. The Pd/HAP catalyst was reused several times though its catalytic performance gradually declined.
- Koizumi, Yu,Jin, Xiongjie,Yatabe, Takafumi,Miyazaki, Ray,Hasegawa, Jun-ya,Nozaki, Kyoko,Mizuno, Noritaka,Yamaguchi, Kazuya
-
supporting information
p. 10893 - 10897
(2019/07/12)
-
- Simultaneous hydrodenitrogenation and hydrodesulfurization on unsupported Ni-Mo-W sulfides
-
The catalytic properties of unsupported Ni-Mo-W sulfides (composites of Ni-Mo(W)S2 mixed sulfides and Ni3S2) obtained from precursors synthesized via co-precipitation, hydrothermal, and thiosalt decomposition were explored
- Albersberger, Sylvia,Hein, Jennifer,Schreiber, Moritz W.,Guerra, Santiago,Han, Jinyi,Gutiérrez, Oliver Y.,Lercher, Johannes A.
-
p. 344 - 355
(2017/09/30)
-
- Selective synthesis of primary anilines from cyclohexanone oximes by the concerted catalysis of a Mg-Al layered double hydroxide supported Pd catalyst
-
Although the selective conversion of cyclohexanone oximes to primary anilines would be a good complement to the classical synthetic methods for primary anilines, which utilize arenes as the starting materials, there have been no general and efficient methods for the conversion of cyclohexanone oximes to primary anilines until now. In this study, we have successfully realized the efficient conversion of cyclohexanone oximes to primary anilines by utilizing a Mg-Al layered double hydroxide supported Pd catalyst (Pd(OH)x/LDH) under ligand-, additive-, and hydrogen-acceptor-free conditions. The substrate scope was very broad with respect to both cyclohexanone oximes and cyclohexenone oximes, which gave the corresponding primary anilines in high yields with high selectivities (17 examples, 75% to >99% yields). The reaction could be scaled up (gram-scale) with a reduced amount of the catalyst (0.2 mol %). Furthermore, the one-pot synthesis of primary anilines directly from cyclohexanones and hydroxylamine was also successful (five examples, 66-99% yields). The catalysis was intrinsically heterogeneous, and the catalyst could be reused for the conversion of cyclohexanone oxime to aniline at least five times with keeping its high catalytic performance. Kinetic studies and several control experiments showed that the high activity and selectivity of the present catalyst system were attributed to the concerted catalysis of the basic LDH support and the active Pd species on LDH. The present transformation of cyclohexanone oximes to primary anilines proceeds through a dehydration/dehydrogenation sequence, and herein the plausible reaction mechanism is proposed on the basis of several pieces of experimental evidence.
- Jin, Xiongjie,Koizumi, Yu,Yamaguchi, Kazuya,Nozaki, Kyoko,Mizuno, Noritaka
-
p. 13821 - 13829
(2017/11/06)
-
- Heterogeneous catalytic synthesis of quinoline compounds from aniline and C1-C4 alcohols over zeolite-based catalysts
-
The synthesis of quinolines from aniline and a C1-C4 alcohol was conducted under gas-phase reaction conditions over a series of zeolite-based catalysts. The texture and acid properties of catalysts were characterized by XRD, FT-IR, BET and NH3-TPD techniques. It was found that the total yield of quinolines was positively related to the relative content of Lewis acid sites of the catalyst. Among others, the ZnCl2/Ni-USY-acid catalyst possessed the best performance. Over this catalyst, the reactions of aniline and most of the alcohols provided a 42.3-79.7% total yield of quinolones under mild conditions, however, those of aniline and methanol, ethanol and iso-propanol predominantly led to N-alkylanilines. Furthermore, the reaction pathways for synthesizing quinolines via aniline reacting with polyhydric alcohols or monohydric alcohols was proposed in our work.
- Huang, Chen,Li, An,Chao, Zi-Sheng
-
p. 48275 - 48285
(2017/10/31)
-
- Preparation and characterization of NiW supported on Al-modified MCM-48 catalyst and its high hydrodenitrogenation activity and stability
-
Al-containing MCM-48 with different Si/Al ratios and aluminum free MCM-48 materials were successfully prepared with hexadecyl trimethyl ammonium bromide (CTAB) and poly(ethylene oxide) poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) as a co-template. A series of characterizations show that both the supports and the NiW supported catalysts are highly ordered. The acid strength of the supports is enhanced when Al is introduced and when its content is increased. The acid amount and strength is further improved by supporting the NiW species. The oxide precursors show a high degree of sulfidation under mild sulfidation conditions. The activity of the Al-modified catalysts for quinoline hydrodenitrogenation (HDN) is much higher than that of aluminum free NiW/MCM-48 and NiW/γ-Al2O3 catalysts. The addition of CS2 to the feed could boost the conversion of quinoline HDN and change the product distribution due to modification of the active site distribution of hydrogenation and C-N bond cleavage. Moreover, the stability of the resulting catalysts was also investigated, and no dramatic decrease in HDN conversion was observed in 960 h, which suggests that they could be candidates for industrial HDN catalysts.
- Shao, Mingqiang,Cui, Haitao,Guo, Shaoqing,Zhao, Liangfu,Tan, Yisheng
-
p. 61747 - 61757
(2016/07/11)
-
- γ-Al2O3-supported and unsupported (Ni)MoS 2 for the hydrodenitrogenation of quinoline in the presence of dibenzothiophene
-
Supported MoS2/γ-Al2O3 and Ni-MoS2/γ-Al2O3 as well as unsupported Ni-MoS2 were investigated in the hydrodenitrogenation (HDN) of quinoline in the presence of dibenzothiophene (DBT). The supported oxide catalyst precursors had a well-dispersed amorphous polymolybdate structure that led to the formation of a highly dispersed sulfide phase. In contrast, the unsupported catalyst precursor consisted of a mixture of nickel molybdate and ammonium nickel molybdate phases that formed stacked sulfide slabs after sulfidation. On all catalysts, the reaction pathway for the removal of N in quinoline HDN mainly followed the sequence quinoline→1,2,3,4- tetrahydroquinoline→decahydroquinoline→propylcyclohexylamine→ propylcyclohexene→propylcyclohexane. The hydrodesulfurization of DBT proceeded mainly by direct desulfurization towards biphenyl. For both processes, the activity increased in the order MoS2/γ-Al 2O32/unsupported2/γ-Al2O3. The promotion of the MoS 2 phase with Ni enhances the activity of the unsupported catalyst to a greater extent than the supported one. However, the multiply stacked unsupported Ni-MoS2 exhibited lower rates than Ni-MoS 2/γ-Al2O3 because of its lower dispersion. I want to break free (from your nitrogen): Ni and Al 2O3 exert particular effects on the physicochemical and kinetic features of molybdenum oxide species and the corresponding MoS 2 phase. The support maximizes the concentration of active sites, whereas the promoter changes their intrinsic activity. In turn, the support also influences the promotion mechanism. Copyright
- Hein, Jennifer,Hrabar, Ana,Jentys, Andreas,Gutierrez, Oliver Y.,Lercher, Johannes A.
-
p. 485 - 499
(2014/03/21)
-
- Competitive hydrodesulfurization of dibenzothiophene and hydrodenitrogenation of quinoline over unsupported MoS2 catalyst
-
The hydrodesulfurization of dibenzothiophene and the hydrodenitrogenation of quinoline were investigated both individually and simultaneously as a mixture over an unsupported synthetic MoS2 catalyst. The reactions were carried out in a batch system under 3 MPa H2 at 340 C. Investigations toward the effect of H2S on the hydrodenitrogenation reaction of quinoline revealed that H2S promoted the transformation of 1,2,3,4-tetrahydroquinoline (THQ1) to ortho-propylaniline (OPA), but had a considerable adverse impact on the transformation of OPA to propylbenzene and its derivatives (C9 products). The hydrodesulfurization of dibenzothiophene proceeded predominantly through a hydrogenation pathway to give cyclohexylbenzene. The hydrodesulfurization of dibenzothiophene was found to be completely inhibited during the initial stages of the reaction, when quinoline was added into the feedstock. The inhibition of the reaction persisted until the quinoline was transformed to a sufficiently low level. Thereafter, the hydrodesulfurization of dibenzothiophene recovered and the reaction proceeded with only moderate inhibition. In contrast, the hydrodenitrogenation of quinoline was significantly enhanced by the presence of dibenzothiophene in the reaction feedstock. The THQ1 and C9 products were the main species obtained from the hydrodenitrogenation reaction of quinoline. The presence of dibenzothiophene enhanced the activity and selectivity toward C9 productions. These results suggested that at least two types of active site were involved in the reaction. Dibenzothiophene could interact with distinct coordinative unsaturated sites, and this could stabilize and increase the acidity of the potential active sites assumed to be responsible for the hydrodenitrogenation reactions.
- Farag, Hamdy,Kishida, Masahiro,Al-Megren, Hamid
-
p. 173 - 182
(2013/11/19)
-
- Ring opening of 1,2,3,4-tetrahydroquinoline and decahydroquinoline on MoS2/γ-Al2O3 and Ni-MoS 2/γ-Al2O3
-
The hydrodenitrogenation of decahydroquinoline (DHQ) and quinoline on MoS2/γ-Al2O3 and Ni-MoS 2/γ-Al2O3 proceeds via two routes. The first one proceeds via DHQ → propylcyclohexylamine → propylcyclohexene → propylcyclohexane, and the ring opening in DHQ is the rate-limiting step. The second route proceeds via 1,2,3,4-tetrahydroquinoline (14THQ) → o-propylaniline → propylcyclohexylamine and propylbenzene with the ring opening of 14THQ and the hydrogenation of o-propylaniline being the rate determining steps (the intrinsic rate of C(sp3)-N bond cleavage being slower in 14THQ than in DHQ). The active sites for the ring opening via Hofmann elimination are acidic -SH groups and basic S2- ions. The parallel conversion of dibenzothiophene (DBT) via direct desulfurization provides increasing concentrations of S2- ions and -SH groups. Nickel facilitates the adsorption of H2S and H2 and the mobility of hydrogen. Thus, the presence of DBT and Ni accelerates the rate of the C(sp3)-N bond cleavage. H2S as sulfur source enhances the ring-opening steps in a minor extent than DBT. The presence of -SH groups and the effect of Ni on them were probed by TPR, TPD and IR-spectroscopy of adsorbed 2,6-dimethylpyridine.
- Gutierrez, Oliver Y.,Hrabar, Ana,Hein, Jennifer,Yu, Yanzhe,Han, Jinyi,Lercher, Johannes A.
-
p. 155 - 168
(2013/01/14)
-
- Rh2(II)-catalyzed intramolecular aliphatic C-H bond amination reactions using aryl azides as the N-atom source
-
Rhodium(II) dicarboxylate complexes were discovered to catalyze the intramolecular amination of unactivated primary, secondary, or tertiary aliphatic C-H bonds using aryl azides as the N-atom precursor. While a strong electron-withdrawing group on the nitrogen atom is typically required to achieve this reaction, we found that both electron-rich and electron-poor aryl azides are efficient sources for the metal nitrene reactive intermediate.
- Nguyen, Quyen,Sun, Ke,Driver, Tom G.
-
supporting information; experimental part
p. 7262 - 7265
(2012/06/16)
-
- One-pot aryl-1,4-thiomorpholine 1,1-dioxide synthesis via double 1,4-addition of in situ reduced nitroarenes to divinyl sulfones
-
One-pot reduction-triggered double aza-Michael type 1,4-addition reactions of various nitroarenes to divinyl sulfones were investigated. In the presence of indium/AcOH in MeOH or in sat. aq NH4Cl/MeOH, nitroarenes and divinyl sulfones were cycl
- Han, Joon Hee,Choi, Jaehwan,Jun, Young Moo,Lee, Byung Min,Kim, Byeong Hyo
-
experimental part
p. 317 - 327
(2010/08/20)
-
- Structural development of liver X receptor (LXR) antagonists derived from thalidomide-related glucosidase inhibitors
-
Following our previous discovery of LXR antagonistic activity of 2′-substituted phenylphthalimides derived from thalidomide-related glucosidase inhibitors, structure-activity studies and further structural development led to 5-chloro-N-2′-n-pentylphenyl-1,3-dithiophthalimide (5CPPSS-50), with IC50 values of about 10 and 13 μM for LXRα and LXR β, respectively.
- Noguchi-Yachide, Tomomi,Miyachi, Hiroyuki,Aoyama, Hiroshi,Aoyama, Atsushi,Makishima, Makoto,Hashimoto, Yuichi
-
p. 1750 - 1754
(2008/09/17)
-
- A new type of nonsulfide hydrotreating catalyst: Nickel phosphide on carbon
-
Nickel phosphide on carbon is successfully synthesized by temperature-programmed reduction as verified with X-ray diffraction and extended X-ray absorption fine structure measurements; it shows superior activity, selectivity, and stability for sulfur removal from the refractory compound 4,6-dimethyldibenzothiophene with a steady-state conversion of 99%, which is much higher than that of a commercial NiMoS/γ-Al2O3 catalyst of 68%. The Royal Society of Chemistry 2005.
- Shu, Yuying,Oyama, S. Ted
-
p. 1143 - 1145
(2007/10/03)
-
- HDN activities of methyl-substituted quinolines
-
Catalytic hydrotreating has become an important process for removal of sulfur and nitrogen from petroleum due to increasing environmental constraints. The HDN reactivities of quinoline (Q) and several methyl-substituted quinolines (MQ) were determined over a NiMo/Al2O3 catalyst and a CoMo/Al2O3 catalyst using a fixed-bed reactor at 613 K and 3.1MPa. For HDN activity, methyl groups on the aromatic ring gave about the same conversion as for Q, while methyl groups on the N ring gave considerably lower HDN conversions, except for 2-MQ, which was higher. Results were essentially the same for the NiMo and CoMo catalysts. All MQs and Q rapidly reached equilibrium between Q and THQ1 (and their respective methyl analogs). Total and HDN activities were roughly related to their respective equilibria, except for 2-MQ, in which the methyl group provided a positive influence. The rate constants for the formation of o-propylaniline from THQ1 correlated well with the electrostatic potential on the N atom of the respective THQl.
- Kim,Simons, Jack,Massoth
-
p. 201 - 206
(2007/10/03)
-
- Mechanism of the hydrodenitrogenation of quinoline over NiMo(P)/Al2O3 catalysts
-
The hydrodenitrogenation (HDN) of quinoline and its reaction intermediates was studied over NiMo(P)/Al2O3 catalysts. Phosphorus exhibited a promotional effect on the HDN of quinoline and ortho-propylaniline and a negative effect on t
- Jian,Prins
-
-
- New Catalysts for Hydroprocessing: Transition Metal Carbides and Nitrides
-
A series of moderate surface area transition metal carbides and nitrides of molybdenum, tunsten, vanadium, niobium, and titanium were prepared by temperature-programmed reaction of the oxide precursor with a reactant gas (20percent CH4/H2 for the carbides and 100percent NH3 for the nitrides).The phase purity and composition of the samples were established by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while surface properties were determined by N2 BET and CO chemisorption measurements.The catalysts were tested in a three-phase trickle-bed reactor for their activity in hydrodenitrogenation (HDN), hydrodesulfurization, and hydrodeoxygenation, with particular emphasis on HDN.The catalytic tests were carried out using a model liquid feed mixture containing 3000 ppm sulfur (dibenzothiophene), 2000 ppm nitrogen (quinoline), 500 ppm oxygen (benzofuran), 20 wt percent aromatics (tetralin), and balance aliphatics (tetradecane).The carbides and nitrides were found to be active for HDN of quinoline with activity following the order group 6 > group 5 > group 4.Notably, Mo2C showed superior areal HDN activity than a commercial sulfided Ni-Mo/Al2O3 catalyst (Shell 324).The XRD analysis of the spent catalysts indicated no change in the bulk structure, while XPS results showed little incorporation of sulfur in the surface region of the catalysts, suggesting that these materials are tolerant of sulfur.
- Ramanathan, S.,Oyama, S. T.
-
p. 16365 - 16372
(2007/10/02)
-
- Para-bromination of ortho-alkyl anilines
-
A process of selectively preparing p-bromo-o-alkylanilines (e.g. 4-bromo-2-methylaniline) by reacting o-alkylanilines (e.g., 2-methylaniline) with unadsorbed bromine in a solvent selected from the group consisting of an inert di- tri- or tetrahaloaliphatic hydrocarbon (e.g., dichloromethane and dibromomethane), an alkyl nitrile (e.g., acetonitrile) and mixtures thereof.
- -
-
-
- HYDRODENITROGENATION OF DECAHYDROQUINOLINE OVER CARBON-SUPPORTED TRANSITION METAL SULFIDE CATALYSTS
-
The catalytic properties of the first, second and third row transition metal sulfides supported on activated carbon (TMSC/C) were investigated for the hydrodenitrogenation of decahydroquinoline in micro-autoclaves at 50 bar total pressure and at 623 K or 653 K.Excluding vanadium sulfide, the first row TMS/C catalysts had very low activity and showed no periodic trend.On the other hand, second and third row TMS/C catalysts were quite active and showed volcano-type periodic trends, with maxima at Rh and Ir sulfides respectively.These periodic trends were very similar to those observed earlier for the TMS/C catalysts in the hydrodenitrogenation of quinoline and in the hydrodesulfurisation of thiophene.
- Sudhakar, C.,Eijsbouts, S.,Beer, V. H. J. de,Prins, R.
-
p. 885 - 890
(2007/10/02)
-
- TRANSFORMATION OF QUINOLINES AND ANILINES OVER NiMo-Al2O3 CATALYSTS
-
The decomposition of nitrogen-containing compounds: 1,2,3,4-tetrahydroquinoline, 6-methylquinoline, decahydroquinoline, orthopropylaniline and 2,6-diethyl,1-aniline, was studied at 623 K, 7 MPa in a continuous flow microreactor over two commercial nickel-molybdenum-alumina catalysts, (HR346 and HR348, Procatalyse).Decahydroquinoline was found to react very rapidly under the conditions of 1,2,3,4-tetrahydroquinoline hydrodenitrogenation.The simultaneous transformations of quinoline and aniline showed that the aniline transformation was inhibited by the quinolines.However the inhibiting effect was much less significant with HR348 which also happens to be more active in aniline transformation.
- Perot, G.,Brunet, S.,Canaff, C.,Toulhoat, H.
-
p. 865 - 870
(2007/10/02)
-
- Hydrodenitrogenation Catalysed by Zeolite-supported Ruthenium
-
Sulphided ruthenium supported on Y-zeolite is a very active catalyst for hydrodenitrogenation; in combination with sulphided nickel molybdate on alumina the activity is gratly enhanced.
- Harvey, Timothy G.,Matheson, Trevor W.
-
p. 188 - 189
(2007/10/02)
-