- Photoreaction of 2-morpholinoacrylonitrile with substituted 1-acetonaphthones. Part II
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Photochemical reactions of substituted 1-acetonaphthones in the presence of 2-morpholinoacrylonitrile were investigated. The type of reaction, photocycloaddition vs. photosubstitution, is dependent on the nature of the additional substituent. The location of the additional substituent on the ring also affects the type of addition, [2 + 2] vs. [4 + 2].
- Memarian,Nasr-Esfahani,Dopp
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- Zeolite catalyzed highly selective synthesis of 2-methoxy-6-acetylnaphthalene by Friedel-Crafts acylation of 2-methoxynaphthalene in acetic acid reaction media
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Zeolite catalyzed Friedel-Crafts acetylation of 2-methoxynaphthalene to produce 2-methoxy-6-acetylnaphthalene with high selectivity and conversion has been a challenging task, because the obtained compound is a key intermediate for an anti-inflammatory agent, Naproxen. However, no satisfactory results have been obtained with zeolite catalysts, and harmful solvents have been used to gain a high selectivity together with a high conversion. Here, we report the synthesis of 2-methoxy-6-acetylnaphthalene from 2-methoxynaphthalene with a high selectivity and a high conversion under an unprecedented simple reaction system; acetic anhydride as an acetylating agent, acetic acid as a solvent, and proton-type zeolite catalysts with low acidity. Among the examined zeolites, a proton-type H-MOR (SiO2/Al2O3 = 200) with a low acid content shows a conversion of 82% and an 86% selectivity for 2-methoxy-6-acetylnaphthalene. Further, detailed control experiments using H-MOR catalyst in acetic acid solvent were carried out to propose a plausible reaction mechanism.
- Yamazaki, Tomoyoshi,Makihara, Makoto,Komura, Kenichi
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p. 170 - 176
(2016/12/09)
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- Hierarchical ZSM-5 zeolite with uniform mesopores and improved catalytic properties
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Hierarchical ZSM-5 with uniform mesoporosity was synthesized by the sequential coupling of two strategies: generation of secondary porosity by the crystallization of silanized protozeolitic units and a subsequent treatment with a basic surfactant-containing solution. The ZSM-5 zeolite obtained exhibited high crystallinity and contained two levels of uniform porosities within the micro- and mesopore ranges, respectively. The uniform mesoporosity is the result of the reorganization of irregular mesopores, created initially from the silanized protozeolitic units, via the local rearrangement of zeolitic fragments, and promoted by contact with a cationic surfactant under mild basic conditions. Interestingly, this second treatment was less effective when it is applied to a non-hierarchical ZSM-5 sample, showing that the presence of initial secondary porosity is essential for allowing the surfactant/ammonia solution to modify the zeolite and form uniform mesopores. Characterization of the zeolite samples using different techniques showed that the crystallinity, Al coordination and acidic features of the zeolite do not change significantly after the mesopore narrowing treatment, even though significant variations in the textural properties are observed as expected. The effects of the occurrence of regular mesoporosity on the catalytic properties of the hierarchical ZSM-5 zeolite were proven using the acylation of 2-methoxynaphthalene as a test reaction. The material with uniform mesopores showed both the highest activity and selectivity towards 6-acetyl-2-methoxynaphthalene, which was interpreted as the result of the presence of a more regular and less rough mesopore surface, which in turn facilitated the interaction between the reactant molecules and the active sites located and distributed over the mesopores.
- Serrano,Escola,Sanz,Garcia,Peral,Moreno,Linares
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p. 4206 - 4216
(2016/06/09)
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- Synthesis of bridged biarylbisquinones and effects of biaryl dihedral angles on photo- and electro-chemical properties
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A series of bridged biarylbisquinones, QBINOLs 1-4, and their corresponding monomers, QNaphs 5-6, were designed to demonstrate the influence of biaryl conformation on the photo- and electro-chemical properties of the molecules. All target compounds were synthesized from the Diels-Alder reaction between silyl enol ethers of the corresponding naphthyl or binaphthyl derivatives and p-benzoquinone. Addition of an OMe auxochrome or formation of the dimeric structures affect the absorption spectra and the energy band gap (Eg), but not the reduction potentials of the molecules. Narrowing the dihedral angles of the QBINOLs by shortening methylene bridges limited the contribution of bridging OR auxochromes and therefore resulted in lower HOMO levels and larger Eg.
- Wongma, Krittaphat,Bunbamrung, Nantiya,Thongpanchang, Tienthong
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p. 1533 - 1540
(2016/03/01)
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- Enhancement in activity and shape selectivity of zeolite BEA by phosphate treatment for 2-methoxynaphthalene acylation
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Pore-engineering of large pores of zeolite BEA by phosphate treatment effectively narrowed the pores with the creation of new acid sites. Phosphate modification of BEA with lower loading was more effective in pore modification without affecting the zeolite structure. Pyrophosphates and polyphosphates are mainly responsible for the narrowing of the zeolite pores. Both the activity and shape selectivity for 2-acetyl-6-methoxynaphthalene were enhanced in the acylation of 2-methoxynaphthalene. At higher concentration of phosphates, conversion and selectivity decreased due to dealumination. 1% P loading was found to be optimum for the acylation of 2-methoxynaphthalene. With the optimized phosphate modification of BEA, high selectivity of 78% to 2-acetyl-6-methoxynaphthalene was achieved with 77% conversion.
- Hodala, Janardhan L.,Halgeri, Anand B.,Shanbhag, Ganapati V.
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p. 90579 - 90586
(2016/10/07)
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- Acetylation of 2-methoxynaphtalene with acetic anhidryde over Zr4+-zeolite beta
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Regioselective acetylation of 2-methoxy naphthalene (2-MN) to 2-acetyl-6-methoxy naphthalene (2,6-ACMN) is the important step in the synthesis of pharmaceutical compounds such as (S)-naproxen. The liquid phase acetylation of 2-MN with acetic anhydride over Zr4+-zeolite beta catalyst was investigated under controlled reaction conditions. Catalyst was prepared by ion exchange and impregnation method. Zr4+-zeolite beta(ie) was obtained by ion exchange that done with 0,5 M ZrCl4 then calcined at 550°C for 3 h and Zr4+-zeolite beta(ip) was obtained by impregnation method. Catalytic activity of catalysts was affected by preparing method, temperature, and reaction solvent. Catalyst that prepared by impregnation showed inactive on acetylation of 2-MN. 1-Acetyl-2-methoxynaphtalene (1,2-ACMN), 1-acetyl-7-methoxy-naphtalene (1,7-ACMN), and 2-acetyl-6-methoxy naphthalene (2,6-ACMN) were identified as the products of 2-MN acetylation over Zr4+-zeolite beta(ie) without solvent. Activity and selectivity of Zr4+-zeolite beta(ie) was increased in dichloromethane solvent at 140°C for 36 h, 1,8-ACMN was not identified and ratio of 1,2-ACMN to 2,6-ACMN was 1,6:1.
- Cahyono, Edy,Priatmoko, Sigit,Haryani, Sri
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Single-step delamination of a MWW borosilicate layered zeolite precursor under mild conditions without surfactant and sonication
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Layered borosilicate zeolite precursor ERB-1P (Si/B = 11) is delaminated via isomorphous substitution of Al for B using a simple aqueous Al(NO 3)3 treatment. Characterization by PXRD shows loss of long-range order, and TEM demonstrates transformation of rectilinear layers in the precursor to single and curved layers in the delaminated material. N 2 physisorption and base titration confirm the expected decrease of micropore volume and increase in external surface area for delaminated materials relative to their calcined 3D zeolite counterpart, whereas FTIR and multinuclear NMR spectroscopies demonstrate synthesis of Bronsted acid sites upon delamination. Comparative synthetic studies demonstrate that this new delamination method requires (i) a borosilicate layered zeolite precursor, in which boron atoms can be isomorphously substituted by aluminum, (ii) neutral amine pore fillers instead of rigid and large quaternary amine SDAs, and (iii) careful temperature control, with the preferred temperature window being around 135 C for ERB-1P delamination. Acylation of 2-methoxynaphthalene was used as a model reaction to investigate the catalytic benefits of delamination. A partially dealuminated delaminated material displays a 2.3-fold enhancement in its initial rate of catalysis relative to the 3D calcined material, which is nearly equal to its 2.5-fold measured increase in external surface area. This simple, surfactant- and sonication-free, mild delamination method is expected to find broad implementation for the synthesis of delaminated zeolite catalysts.
- Ouyang, Xiaoying,Hwang, Son-Jong,Runnebaum, Ron C.,Xie, Dan,Wanglee, Ying-Jen,Rea, Thomas,Zones, Stacey I.,Katz, Alexander
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p. 1449 - 1461
(2014/02/14)
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- Catalytic applications of OSDA-free Beta zeolite
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Beta zeolite obtained from seeded synthesis without the use of organic structure directing agents (OSDAs) has been used as a catalyst in different types of reactions. The large number of strong acid sites resulted in a high activity for the alkylation of benzene with ethene and a high cracking activity in the hydroconversion of n-decane. However, the high framework polarity resulted in fast deactivation in the acylation of aromatic ethers. Dealumination treatments resulted in improved stability in alkylation reactions with the more reactive olefins like propene. In acylation reactions, the activity was significantly increased, and in hydroconversion, a better balance between the hydrogenation/dehydrogenation and the acid sites was obtained.
- De Baerdemaeker, Trees,Yilmaz, Bilge,Mueller, Ulrich,Feyen, Mathias,Xiao, Feng-Shou,Zhang, Weiping,Tatsumi, Takashi,Gies, Hermann,Bao, Xinhe,De Vos, Dirk
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- Preparation and characterization of Zr-MCM-41 synthesized under microwave irradiation condition for acetylation of 1,2-dimethoxybenzene with acetic anhydride
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The liquid phase of acetylation of 1,2-dimethoxybenzene with acetic anhydride has been investigated over a series of acid zirconium mesoporous materials (Zr-MCM-41) synthesized by a microwave irradiation method with different Si/Zr ratios (Si/Zr = 90, 60, 10) and characterized by several spectroscopic techniques such as: N2 physical adsorption, ICP, XRD, TEM, FT-IR, UV-vis and a temperature-programmed desorption (TPD) of pyridine. In fact, the catalyst Zr-MCM-41 (10) showed a greater performance in the acid-catalyzed acetylation of 1,2-dimethoxybenzene employing acetic anhydride as an acylating agent. Furthermore, the kinetics of the acetylation of 1,2-dimethoxybenzene over these catalysts have also been investigated. Springer Science+Business Media B.V. 2011.
- Bachari,Chebout,Guerroudj,Lamouchi
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experimental part
p. 367 - 381
(2012/06/01)
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- Assessment of the catalytic activities of novel broensted acidic ionic liquid catalysts
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Broensted acidic ionic liquids (BILs) were synthesized by a two step synthetic protocol. Catalytic activities of BILs were assessed by means of suitable catalytic reactions such as acylation of 2-methoxynapthalene with acetic anhydride, Biginelli reaction to synthesize 3,4-dihydropyrimidin-2(1H)- one, stereoselective synthesis of β-amino ketone via direct Mannich-type reaction and esterification of hexanoic acid with benzyl alcohol. Catalytic activities of BILs were high when compared with those of solid acid catalysts such as ZSM-5, beta, dealuminated beta and Al-SBA-15. BILs catalysts were found to be highly stereo/regio-selective for above mentioned reactions. Novel BILs catalyst offers several attractive features such as low cost, high catalytic activity/selectivity and recyclability. Graphical Abstract: N-methylimidazole and pyridine derived Broensted acidic ionic liquids were found to be highly active and stereo/regio-selective compared to various solid acid catalysts in fine chemicals (1-5) synthesis.[Figure not available: see fulltext.]
- Srivastava, Rajendra
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experimental part
p. 17 - 25
(2010/12/25)
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- Acetylation of aromatic compounds over H-BEA zeolite: The influence of the substituents on the reactivity and on the catalyst stability
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The acylation with acetic anhydride of six aromatic substrates with different features (degree of activation of the aromatic ring towards electrophilic substitution, number of rings, i.e., 1 or 2) was carried out in a batch reactor at 373 K over a H-BEA zeolite (Si/Al = 15) with nitrobenzene as a solvent. The acetylation rate was found to be very dependent on the degree of ring activation, with diffusion limitations playing only a limited role. The decrease of the rate with reaction time, which was very pronounced with poorly activated and deactivated substrates, is mainly due to the inhibiting effect of acetic acid and of the products of acetic anhydride condensation.
- Guidotti, Matteo,Canaff, Christine,Coustard, Jean-Marie,Magnoux, Patrick,Guisnet, Michel
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p. 375 - 383
(2007/10/03)
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- Zeolite catalysts for fine chemicals synthesis. Acetylation of 2-methoxynaphthalene
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Acetylation of 1-methoxynaphthalene into 2-acetyl-6-methoxynaphthalene, which is a precursor of the anti-inflammatory S-Naproxen, was chosen as an example to show the great potentialities of zeolite catalysts for substituting polluting and corrosive Friedel-Crafts catalysts. A selective and clean process can be developed using acetic anhydride, as acylating agent, and a HBEA zeolite with a Si/Al ratio between 20 and 40 and without extraframework aluminum species, as catalyst. Adsorption experiments demonstrate that all the acetyl-methoxynaphthalene isomers can enter the BEA micropores hence can be formed within these pores. The strong interactions between the polar molecules of reactants and products and the micropore walls were shown to determine both the reaction scheme and the mechanisms. These interactions play a more important role than product shape selectivity in the kinetically limiting desorption of products.
- Guisnet,Moreau,Magnoux
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p. 203 - 218
(2007/10/03)
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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 21,22
(2008/06/13)
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- Al-ITQ-7, a Shape-Selective Zeolite for Acylation of 2-Methoxynaphthalene
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Acylation of 2-methoxynaphthalene with acetic anhydride has been carried out with a tridirectional 12-member ring pore zeolite named ITQ-7, which has a slightly smaller pore diameter than zeolite Beta. ITQ-7 is as active as Beta but gives better selectivity to 2-acetyl-6-methoxynaphthalene (2-AMN). This is due to the differences in the relative diffusion coefficients of 2-AMN and 1-acetyl-2-methoxynaphthalene (1-AMN), whose ratios are 2.7 and 15.5 in Beta and ITQ-7, respectively. In general, it can be said that when decreasing the zeolite crystallite size, the reaction rate increases, although the selectivity to 2-AMN decreases.
- Botella,Corma,Sastre
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- Remarkable effect of lithium salts in Friedel-Crafts acylation of 2-methoxynaphthalene catalyzed by metal triflates
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In the presence of a catalytic amount of a metal triflate such as Sb(OTf)3 or Ga(OTf)3, 2-methoxynaphthalene reacted with acetic anhydride in nitromethane-lithium perchlorate to afford 2-acetyl-6-methoxynaphthalene, a well-known intermediate for the synthesis of naproxen, in a high yield. (C) 2000 Elsevier Science Ltd.
- Kobayashi,Komoto
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p. 6463 - 6465
(2007/10/03)
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- Friedel-crafts reactions catalyzed by rare earth metal trifluoromethanesulfonates
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Rare earth metal trifluoromethanesulfonates (rare earth metal trifiates, RE(OTf)3) were found to be efficient catalysts for Friedel-Crafts acylation and alkylation. In the presence of a catalytic amount of RE(OTf)3, acylation of aromatic compounds having electron-donating substituents such as anisole, thioanisole, and mesitylene with acid anhydrides proceeded smoothly to afford the corresponding aromatic ketones in high yields. Although RE(OTf)3 alone is not effective for acylation of less reactive aromatics such as toluene, the combination of RE(OTf)3 and lithium perchlorate (LiClO4) enhanced the catalytic activity dramatically. Friedel-Crafts acylation reactions using rare earth metal perfluoroalkanesulfonates were also successfully performed in supercritical carbon dioxide (scCO2). Moreover, in the presence of a catalytic amount of RE(OTf)3, aromatic compounds reacted with benzyl chloride smoothly to afford the corresponding alkylation products in high yields. In these reactions, RE(OTf)3 could be easily recovered after the reactions were completed and could be reused without loss of activity.
- Kawada, Atsushi,Mitamura, Shuichi,Matsuo, Jun-Ichi,Tsuchiya, Takehiro,Kobayashi, Shu
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p. 2325 - 2333
(2007/10/03)
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- Acylation of 2-methoxynaphthalene and isobutylbenzene over zeolite beta
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The acylation of 2-methoxynaphthalene (2MN) and isobutylbenzene using several zeolite beta samples having varius Si/Al ratios and crystal sizes to examine whether external surface sites could be eliminated to enhance the catalyst performance to obtain a viable acylation catalyst for the formation of precursors to the nonsteroidal anti-inflammatory agents naproxen and ibuprofen. Zeolite beta was active for the acylation of 2MN but was not selective to the desired product, 2-acetyl-6-methoxynaphthalene (2,6-AMN). Mild operating conditions (temperature and acylating agent concentration) could be used to obtain reasonable conversions and to limit catalyst deactivation. The other key product, 1-acetyl-2-methoxynaphthalene (1,2-AMN) formed on the external surface of the zeolite, while 2,6-AMN occurred in the zeolite pores. Thus, the selectivity to 2,6-AMN was enhanced on zeolite beta samples having a larger crystal size, on which most of the acid sites could be passivated by coating the crystals with a layer of amorphous silica. The amount of surface coating on the large crystals determined the yield of and the selectivity to 2,6-AMN. Isobutylbenzene was less reactive than 2MN but the desired product, 4-isobutylacetophenone, was always obtained since the isobutyl group provides for the para position being the preferred sites for acylation. For isobutylbenzene, the zeolite external surface contributed significanlty to the formation of 4-isobutylacetophenone. Zeolite beta with a small crystal size was, thus, the most favored catalyst for this reaction.
- Andy,Garcia-Martinez,Lee,Gonzalez,Jones,Davis
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p. 215 - 223
(2007/10/03)
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- Acylation of 2-methoxynaphthalene in the presence of modified zeolite HBEA
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The influence of postsynthesis treatment such as calcination and acid treatment of zeolite HBEA has been studied in the acylation of 2-methoxynaphthalene with acetic anhydride. The contribution of the inner and outer surface of zeolite HBEA is examined by conversion and product selectivity to a bulky product, which can be formed only on the outer surface of HBEA, and to a linear product, which can be formed on the inner and outer surfaces. Calcination under high heating rate enhances the catalytic activity of the inner surface due to the formation of extraframework alumina species in the micropores. FTIR-adsorption experiments of the bulky probe molecule 2,4,6-tri-tert-butylpyridine, which does not fit into the micropores, revealed that these alumina species are located preferentially in the micropores of HBEA. Acid treatment increases the catalytic activity of the outer surface due to the extraction of catalytically active extraframework alumina species out of the micropores and due to the formation of silanol groups, respectively.
- Heinichen,Hoelderich
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p. 408 - 414
(2007/10/03)
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- Acylation of 2-Methoxynaphthalene with Acyl Clorides in the Presence of a Catalytic Amount of Lewis Acids
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The regiochemistry of the reaction of 2-methoxynaphthalene 1 with benzoyl chloride 2a using a catalytic amount of Lewis acid is strongly influenced by the identity of the acid catalyst employed as well as by the reaction temperature.By using InCl3, FeCl3, SnCl4 or ZnCl2 and heating at 160 deg C, 2-benzoyl-6-methoxynaphthalene 4a is selectively produced along with 1-benzoyl-7-methoxynaphthalene 5a, while in the case of AlCl3, SbCl5 or TiCl4, 1-benzoyl-2-methoxynaphthalene 3a is the major product. 2-Acyl-6-methoxynaphthalenes 4b-e can be selectively obtained using InCl3 and the corresponding acyl chlorides 2b-e in place of 2a.In the presence of a stoichiometric amount of InCl3, the reaction of 1 with 2a also gives 4a as the predominant product along with 5a even at 50 deg C.This reaction appears to involve isomerisation of 3a to 4a and 5a.
- Pivsa-Art, Sommai,Okuro, Kazumi,Miura, Masahiro,Murata, Satoru,Nomura, Masakatsu
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p. 1703 - 1708
(2007/10/02)
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- THE SHAPE-SELECTIVE ACYLATION OF 2-METHOXYNAPHTHALENE, CATALYZED BY ZEOLITES Y, BETA AND ZSM-12
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The Friedel-Crafts acylation of 2-methoxynaphthalene (2MN) was investigated using zeolites USY, Beta and ZSM-12 as catalysts under batch conditions at 100 and 180 deg C.Two ketone isomers, 1-acetyl-2-methoxynaphthalene (1AC) and 2-acetyl-6-methoxynaphthalene (2AC) were produced; the selectivity of the reaction could be influenced by the zeolite used.USY produced only the 1AC isomer whereas Beta and ZSM-12 produced both.Selective synthesis of 2AC was achieved by optimization of the reaction conditions using zeolite Beta as the catalyst.It was also observed that the 1AC ketone is unstable in contact with acid zeolite catalysts and undergoes protiodeacylation, a reaction previously only observed in the presence of strong mineral acids.
- Harvey, Gillian,Maeder, Georg
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p. 862 - 868
(2007/10/02)
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