- The isopropylation of naphthalene with propene over H-mordenite: The catalysis at the internal and external acid sites
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The isopropylation of naphthalene (NP) with propene over H-Mordenite (MOR) was studied under a wide range of reaction parameters: temperature, propene pressure, period, and NP/MOR ratio. Selective formation of 2,6-diisopropylnaphthalene (2,6-DIPN) was observed at reaction conditions, such as at low reaction temperature, under high propene pressure, and/or with high NP/MOR ratio. However, the decrease in the selectivities for 2,6-DIPN was observed at reaction conditions such as at high temperature, under low propene pressure, and/or with low NP/MOR ratio. The selectivities for 2,6-DIPN in the encapsulated products were remained high and constant under all reaction conditions. These results indicate that the selective formation of 2,6-DIPN occurs through the least bulky transition state due to the exclusion of the bulky isomers by the MOR channels. The decrease in the selectivities for 2,6-DIPN are due to the isomerization of 2,6-DIPN to 2,7-DIPN at the external acid sites, directing towards thermodynamic equilibrium of DIPN isomers.
- Sugi, Yoshihiro,Anand, Chokkalingam,Subramaniam, Vishnu Priya,Stalin, Joseph,Choy, Jin-Ho,Cha, Wang Soo,Elzatahry, Ahmed A.,Tamada, Hiroshi,Komura, Kenichi,Vinu, Ajayan
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- Alkylation of naphthalene with propylene catalyzed by aluminum chloride immobilized on Al-MCM-41
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AlCl3 catalysts immobilized on mesoporous Al-MCM-41 were prepared by a two step vapor method and their catalytic performance was evaluated for the alkylation of naphthalene with propylene in a slurry bubble column reactor. The physico-chemical properties of the supports and catalysts were characterized by X-ray diffraction, N2 adsorption, and pyridine adsorption infrared spectroscopy. The halide loadings of the catalysts were analyzed by a chemical method. For the alkylation of naphthalene with propylene over AlCl3/Al-MCM-41, pore diameters that match the molecular dimensions of 2,6-diisopropylnaphthalene (2,6-DIPN) and an appropriate amount of [-O-AlCl2] in the catalyst are key to controlling activity and selectivity. The AlCl3 catalyst immobilized on mesoporous H/Al-MCM-41 with a Si/Al ratio of 15 exhibited high activity when the alkylation was carried out at 0.1 MPa and 85 °C for 5 h. A naphthalene conversion of 82.1 and a 2,6-DIPN selectivity of 32.2 were obtained.
- Tang, Hua,Ji, Min,Wang, Xinkui,He, Min,Cai, Tianxi
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- MOR/SBA-15 Composite Catalysts with Interconnected Meso/Micropores for Improved Activity and Stability in Isopropylation of Naphthalene
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The isopropylation of naphthalene with isopropyl alcohol was studied over composites of MOR/SBA-15 in a high-pressure, fixed-bed reactor. The MOR catalyst showed a high 2,6-/2,7-diisopropyl naphthalene (DIPN) ratio of 1.75, but a low naphthalene conversion (54%) and fast deactivation of the catalyst. The composites of MOR/SBA-15 were prepared by a hydrothermal recrystallization process to obtain hierarchical micro/mesopores. During the process, MOR recrystallized in the mesopores of SBA-15, the structure of which was stabilized by carbon coating formed on the pore walls as a template. The best prepared MOR/SBA-15 catalyst achieved a high conversion of 85%, high stability, and less coking, while maintaining the high 2,6-/2,7-DIPN ratio (≈1.8). The modified micro/mesopore structure allowed facile diffusion of bulky molecules to and from active catalytic sites located in the small MOR pores as a result of the connection between the two types of pores in the MOR/SBA-15 composite. Networking of big and small: To improve naphthalene conversion in isopropylation of naphthalene, a hierarchical meso/micropore structure of zeolite composites is achieved by combining micropores of MOR with mesopores of SBA-15. In the hydrothermal recrystallization process, MOR recrystallizes in the mesopores of SBA-15 stabilized by carbon coating formed on the pore walls as a template.
- Banu, Marimuthu,Lee, Young Hye,Magesh, Ganesan,Nam, Chang-Mo,Lee, Jae Sung
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- Isomerization of diisopropylnaphthalenes on wide-pore zeolites
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Experiments on the isomerization of diisopropylnaphthalenes (DIPNs) (i.e., of the slim isomer 2,6-DIPN and of the mixture of bulky isomers 1,3-DIPN and 1,7-DIPN) were carried out over wide-pore zeolites HY, H-beta, and H-mordenite and comparatively over an amorphous aluminosilicate. The external surface of the tested zeolites was very efficient in the isomerization of the DIPN isomers. However, the observed shape selectivity effects suggested that the activity of the pore entrances was more significant than the activity of the non-shape-selective external surface. In the products of isomerization of 2,6-DIPN over the H-beta and H-mordenite, the bulky 1,6-DIPN appeared more quickly than the slim 2,7-DIPN. However, a higher concentration of 2,7-DIPN in the product obtained over the HY zeolite indicated that the product was also formed inside the pores of this zeolite. The external surface of zeolites H-beta and HY revealed a higher activity in the isomerization of 1,7-DIPN than in the isomerization of 2,6-DIPN. Therefore, a better fit to the pore entrances of the former isomer than to the latter was proposed to explain this shape-selectivity effect. On the other hand, the H-mordenite catalyst was more active in the isomerization of 2,6-DIPN than in that of 1,7-DIPN. All tested zeolites demonstrated very low conversion of 1,3-DIPN when compared with the amorphous aluminosilicate.
- Brzozowski, Robert
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- Microwave-assisted regioselective alkylation of naphthalene compounds using alcohols and zeolite catalysts
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Regioselective alkylation of naphthalene compounds with alcohols smoothly proceeded in the presence of zeolite catalysts under microwave irradiation. A H-mordenite (H-M) zeolite catalyst (SiO2/Al2O3 ratio = 240) showed the highest efficiency. In the microwave reactions, high reaction rates and high selectivities for 2,6-dialkylnaphthalenes were achieved. In the best case for the reaction of 2-isopropylnaphthalene with isopropyl alcohol, the conversion and the selectivity were 43.5% and 66.4%, respectively. In di-tert-butylation of naphthalene with tert-butyl alcohol, the conversion and the selectivity reached 86.5% and 70.4%, respectively. The conversions and the selectivities were generally higher than those obtained by conventional oil bath heating.
- Yamashita, Hiroshi,Mitsukura, Yumi,Kobashi, Hiroko,Hiroki, Kazuaki,Sugiyama, Jun-ichi,Onishi, Kiyotaka,Sakamoto, Tetsuo
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- Mesoporous silica-immobilized aluminium chloride as a new catalyst system for the isopropylation of naphthalene
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Mesoporous MCM-41 silica immobilized aluminium chloride shows high catalytic activity and selectivity in the Friedel - Crafts alkylation of naphthalene with isopropanol.
- Zhao,Lu,Song
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- The isopropylation of naphthalene over USY zeolite with FAU topology. The selectivities of the products
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The isopropylation of naphthalene (NP) over USY zeolite (FAU06, SiO2/Al2O3 = 6) gave all eight possible diisopropylnaphthalene (DIPN) isomers: β,β- (2,6- and 2,7-), α,β- (1,3-, 1,6-, and 1,7-), and α,α- (1,4- and 1,5-). Th
- Sugi, Yoshihiro,Joseph, Stalin,Ramadass, Kavitha,Indirathankam, Sathish Clastinrusselraj,Premkumar, Selvarajan,Dasireddy, Venkata D.B.C.,Yang, Jae-Hun,Al-Muhtaseb, Alaa H.,Liu, Qing,Kubota, Yoshihiro,Komura, Kenichi,Vinu, Ajayan
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p. 606 - 615
(2021/03/31)
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- Method for naphthalene alkylation
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The invention relates to a method for naphthalene alkylation, and mainly solves the problems of poor selectivity and easy deactivation of catalysts in the prior art. The method provided by the invention comprises the following steps: a) mixing a silicon source, an aluminum source, a base, water and a template agent to obtain an initial colloid, and then performing hydrothermal crystallization to obtain a ZSM-5/ZSM-12 composite molecular sieve; b) carrying out ion exchange modification on the prepared composite molecular sieve, and carrying out roasting and silanization modification to obtain anaphthalene alkylation catalyst; and c) applying the obtained naphthalene alkylation catalyst to a naphthalene alkylation reaction. When the naphthalene alkylation catalyst prepared by the method provided by the invention is used to carry out the naphthalene alkylation reaction, the selectivity of 2,6-diisopropylnaphthalene is high, meanwhile, the time when the naphthalene alkylation catalyst gets deactivated is postponed, and a good technical effect is obtained. The technical scheme provided by the invention can be well applied to the naphthalene alkylation reaction.
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Paragraph 0034-0162
(2018/05/16)
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- Production method of diisopropylnaphthalene
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The invention relates to a production method of diisopropylnaphthalene, and mainly solves the problems in the prior art that 2,6-diisopropylnaphthalene is low in selectivity and quick in catalyst deactivation; the catalyst used in the production method is organic silicalite which comprises components in the following mole relationship: (1/n)Al2O3:SiO2:(m/n)R, wherein in the formula n=5-250, m=0.01-50, and R is at least one from alkyl, alkylene or phenyl; the Si29 solid-state NMR (nuclear magnetic resonance) spectroscopy of the organic silicalite at least includes one Si29 nuclear magnetic resonance spectral peak between -80-+50 ppm; the X-ray diffraction pattern of the organic silicalite has the maximum spacing value d at 12.4+/-0.2, 11.0+/-0.3, 9.3+/-0.3, 6.8+/-0.2, 6.1+/-0.2, 5.5+/-0.2, 4.4+/-0.2, 4.0+/-0.2 and 3.4+/-0.1 angstroms, so that the organic silicalite can be used in industrial production of diisopropylnaphthalene.
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Paragraph 0101-0112
(2017/01/02)
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- Method for nathphalene alkylation
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The invention relates to a method for nathphalene alkylation, and mainly aims to solve the problems of relatively poor catalyst selectivity and high inactivation in the prior art. The method comprises the following steps: a), adopting a silicon source, an aluminum source and an organic amine template as raw materials, carrying out hydrothermal crystallization and deionized water washing in sequence to obtain a zeolite precursor material; b), conducting ion exchange on the obtained zeolite precursor material for modification, calcining the modified material to obtain a nathphalene alkylation catalyst; c) applying the nathphalene alkylation catalyst to a nathphalene alkylation reaction, wherein ions adopted for ion exchange are at least one of alkaline-earth metal ions and lanthanum metal ions. The method has the advantages that the problem of relatively poor catalyst selectivity in the prior art is solved relatively well, and the suitability to industrial production of nathphalene alkylation is very high.
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Paragraph 0036; 0037
(2016/12/16)
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- Isopropylation of naphthalene by isopropanol over conventional and Zn- and Fe-modified USY zeolites
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Catalytic performances of USY, MOR, and BEA zeolites were compared for the isopropylation of naphthalene by isopropyl alcohol in a high-pressure, fixed-bed reactor. The USY catalyst showed a high conversion of 86% and good stability but a low 2,6-/2,7-DIPN shape selectivity ratio of 0.94. In contrast, over the MOR catalyst, 2,6-DIPN was selectively synthesized with a high 2,6-/2,7-DIPN ratio of 1.75, but low naphthalene conversions and fast deactivation of the catalyst were observed. The USY catalyst was modified by Zn and Fe using the wet impregnation method to enhance the selectivity for 2,6-DIPN. The highest conversion (~95%) and selectivity for 2,6-DIPN (~20%) were achieved with 4% Zn/USY catalyst. It appeared that small metal oxide islands formed in the USY pores to decrease the effective pore size and thus render it mildly shape-selective. Zn loading also decreased the number of strong acid sites responsible for coke formation and increased the number of weak acid sites. The high conversion and stability of Zn-modified catalysts were ascribed to the presence of a suitable admixture of weak and strong acid sites with less coke deposition. The Fe-modified USY catalysts were less effective because the modification increased the number of the strong acid sites.
- Banu, Marimuthu,Lee, Young Hye,Magesh, Ganesan,Lee, Jae Sung
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p. 120 - 128
(2014/01/06)
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- Shape-selective synthesis of 2,6-diisopropylnaphthalene on H-mordenite catalysts
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To finally dispel any doubts on the shape-selective formation of 2,6-diisopropylnaphthalene (2,6-DIPN) over H-MOR zeolites, naphthalene alkylation was carried out over high-silica H-MOR catalysts with propylene or isopropanol as an alkylating agent and with or without cyclohexane as a solvent. Isomeric composition of DIPN's, determined by one-dimensional GC analysis, was additionally confirmed with advanced two-dimensional GC × GC. Our results proved beyond any doubt shape-selective formation of 2,6-DIPN over these H-MOR catalysts from naphthalene and propylene and without cyclohexane as a solvent. The DIPN mixture contained 60-64% 2,6-DIPN, and the ratio of 2,6-DIPN/2,7-DIPN was in the range 2.5-2.8. We also showed that shape-selective formation of 2,6-DIPN over H-MOR catalyst was depressed by using isopropanol instead of propylene and in the presence of cyclohexane.
- Brzozowski, Robert,Buijs, Wim
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experimental part
p. 181 - 187
(2012/10/07)
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- Shape-selective isopropylation of aromatic hydrocarbons over h-mordenite in supercritical carbon dioxide medium
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The isopropylation of aromatic hydrocarbons isobutylbenzene (IBB), naphthalene (NP), and biphenyl (BP) was examined over H-mordenite (MOR), H-β (BEA), and H-Y (FAU) zeolites in supercritical carbon dioxide (sc-CO2) medium. MOR was only selective for the formation of the least bulky 4-isobutylcumene (4-IBC) in the isopropylation of IBB. In particular, the catalytic activity and selectivity for 4-IBC were enhanced by the dealumination of MOR; MOR with 110 of SiO2/Al2O3 ratio rendered the highest performance; however, the catalytic activity was decreased by further dealumination. Thermogravimetric analyses confirmed the reduction of coke formation on the catalysts in sc-CO2 medium, preventing the deactivation of MOR. Shape-selective formation of the least bulky isomers, 2,6- diisopropylnaphthalene (2,6-DIPN) and 4,4′-diisopropylbiphenyl (4,4′-DIPB), was also observed in the isopropylation of NP and BP over MOR in sc-CO2. sc-CO2 works as an efficient medium to access and/or replace substrates and their products to/from acidic sites in the MOR channels. In particular, the removal of coke precursors from acidic sites on the zeolite is enhanced by the sc-CO2 medium, resulting in decreased coke formation.
- Laha, Subhash Chandra,Naiki, Hiroaki,Komura, Kenichi,Sugi, Yoshihiro
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supporting information; body text
p. 1283 - 1290
(2012/01/31)
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- Comparison of the catalytic performance of the metal substituted cage type mesoporous silica catalysts in the alkylation of naphthalene
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Alkylation of naphthalene with propylene to diisopropylnaphthalenes (DIPN) for the use as a high-quality solvent was carried out over mesoporous AlSBA-1, GaSBA-1 and FeSBA-1 catalysts. The AlSBA-1 and GaSBA-1 catalysts were very active in alkylation while the FeSBA-1 samples, although initially active, deactivated quickly. Activity of the SBA-1 catalysts increased with the amount of Al, Ga or Fe incorporation into the silica framework. Regardless of the alkylation activity, all SBA-1 catalysts showed rather low isomerization activity and as a result low 2,6-DIPN selectivity was observed. The AlSBA-1 and GaSBA-1 catalysts proved to be promising for DIPN solvent synthesis due to their high alkylation activity and stability together with low 2,6-DIPN selectivity.
- Brzozowski, Robert,Vinu, Ajayan,Gil, Barbara
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experimental part
p. 76 - 82
(2010/08/06)
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- Dialkylation of naphthalene with isopropanol over H3PO 4/MCM-41 Catalysts for the environmentally friendly synthesis of 2,6-dialkylnaphthalene
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AlMCM-41 materials with SiO2/Al2O3 molar ratios 20, 70, 110, 150, 200, and Si-MCM-41 were synthesized following standard procedures, and loaded with different amounts of H3PO4. The catalysts were well
- Ghiaci,Aghabarari,Rives,Vicente,Sobrados,Sanz
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experimental part
p. 141 - 149
(2010/08/20)
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- Shape-selective diisopropylation of naphthalene in H-Mordenite: Myth or reality?
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Selective diisopropylation of naphthalene to 2,6-diisopropylnaphthalene is a challenging goal in sustainable catalysis. Ultrastable Y and H-Mordenite zeolites are the best catalysts reported in the literature with respect to 2,6-diisopropylnaphthalene selectivity. It is generally accepted that in the case of H-Mordenite, shape-selectivity is responsible for the observed 2,6-diisopropylnaphthalene selectivity, while on Ultrastable Y-zeolite, the observed selectivity reflects the internal thermodynamic equilibrium of positional isomers. Revisiting both the experimental and the computational work in this field now leads to the conclusion that shape-selectivity of whatever kind can be ruled out in the case of H-Mordenite. H-Mordenite catalysts produce usually a kinetically controlled mixture of diisopropylnaphthalene isomers which can shift to the direction of a thermodynamical distribution at high reaction temperatures or over more active catalysts.
- Bouvier, Christophe,Buijs, Wim,Gascon, Jorge,Kapteijn, Freek,Gagea, Bogdan C.,Jacobs, Pierre A.,Martens, Johan A.
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scheme or table
p. 60 - 66
(2010/06/19)
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- The alkylation of naphthalene over one-dimensional fourteen-membered ring zeolites. the influence of zeolite structure and alkylating agent on the selectivity for dialkylnaphthalenes
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The alkylation, i.e., isopropylation, s-butylation, and t-butylation, of naphthalene (NP) was examined over one-dimensional fourteen-membered (14-MR) zeolites: CIT-5 (CF1), UTD-1 (DON), and SSZ-53 (SFH), and compared to the results over H-mordenite (MOR)
- Sugi, Yoshihiro,Maekawa, Hiroyoshi,Naiki, Hiroaki,Komura, Kenichi,Kubota, Yoshihiro
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experimental part
p. 1166 - 1174
(2009/05/06)
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- The alkylation of naphthalene over one-dimensional twelve-membered ring zeolites. the influence of zeolite structure and alkylating agent on the selectivity for dialkylnaphthalenes
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Alkylation, i.e., isopropylation, s-butylation, and t-butylation, of naphthalene (NP) was examined over one-dimensional twelve-membered (12-MR) zeolites: H-mordenite (MOR), SSZ-24 (AFI), SSZ-55 (ATS), and SSZ-42 (IFR) in order to elucidate how zeolite str
- Sugi, Yoshihiro,Maekawa, Hiroyoshi,Naiki, Hiroaki,Komura, Kenichi,Kubota, Yoshihiro
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supporting information; experimental part
p. 897 - 905
(2009/04/14)
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- Disproportionation of isopropylnaphthalene on zeolite catalysts
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Disproportionation of isopropylnaphthalene (IPN) was tested over H-mordenite, HY, H-beta zeolites and over amorphous aluminosilicate in the range of 150-300°C. High β,β-selectivity in diisopropylnaphthalene (DIPN) product obtained over zeolites was observed. However, the 2,6-DIPN/2,7-DIPN mole ratio was dependent on the pore structure of the applied zeolite and on the temperature. Over H-mordenites 2,6-DIPN was the most preferred isomer, whereas 2,7-DIPN was favored over HY and H-beta zeolites. Such disproportion in isomer predominating in the DIPN product can be explained by a bimolecular mechanism of disproportionation. Due to the zeolite pore architecture the bent transition-state complex, leading to 2,7-DIPN (HY and H-beta) or more linear, leading to 2,6-DIPN (H-mordenite), was preferred. At high temperatures the monomolecular disproportionation mechanism (dealkylation realkylation) dominated and concealed (simultaneously with side reactions) the shape-selectivity effect. As a result the 2,6-DIPN/2,7-DIPN mole ratio in the product approached equilibrium value.
- Brzozowski, Robert,Skupinski, Wincenty
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- Isopropylation of naphthalene by isopropyl alcohol over USY catalyst: An investigation in the high-pressure fixed-bed flow reactor
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Catalytic performances of USY, H-mordenite, dealuminated H-mordenite, and H-MCM-22 zeolite catalysts in the isopropylation of naphthalene by isopropyl alcohol with decalin or cyclohexane as a solvent were compared in a high-pressure fixed-bed flow reactor. For the USY catalyst, reaction conditions, such as reaction temperature and pressure, reactant ratio and space velocity, and solvent concentration and type, were controlled to investigate in detail the effect of reaction conditions on the catalytic activity. Over H-mordenite, it was found that 2,6-diisopropylnaphthalene (2,6-DIPN) could be selectively synthesized with a 2,6-/2,7-DIPN ratio of 2.46, and dealumination could enhance not only the selectivity of 2,6-DIPN, with a 2,6-/2,7-DIPN ratio of 2.67, but also the conversion of naphthalene, which was 27.4%, three times as high as that over the unmodified one at 6 h of reaction time on stream. However, neither the H-mordenite or the dealuminated one were catalytically stable and the selectivity of DIPN was at a very low level of less than 12%. In contrast, over the USY catalyst, a high and stable conversion of about 90%, a high selectivity of DIPN of more than 40%, and a considerable 2,6-/2,7-DIPN ratio of 1.46 could be achieved by adjusting the reaction conditions, although no shape selectivity was observed on USY. On the other hand, only a low 2,6-/2,7-DIPN ratio of 0.47 with a low conversion of about 30% was revealed over H-MCM-22, which indicates that the reaction takes place on the external surface of this zeolite. An attempt has been made to explain the catalytic activity, selectivity, and stability in relation to the zeolite structures, product properties, and reaction conditions.
- Wang, Jun,Park, Jung-Nam,Park, Yong-Ki,Lee, Chul Wee
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p. 265 - 272
(2007/10/03)
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- Shape-selective Synthesis of 2,6-Diisopropylnaphthalene over H-Mordenite Catalyst
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2,6-Diisopropylnaphthalene is selectively produced in the liquid phase alkylation of naphthalene with propene or propan-2-ol over H-mordenite catalyst.
- Katayama, Atsuhiko,Toba, Makoto,Takeuchi, Genki,Mizukami, Fujio,Niwa, Shu-ichi,Mitamura, Shuichi
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