- Influence of nanoscale distribution of Pd particles in the mesopores of MCM-41 on the catalytic performance of Pd/MCM-41
-
Two different nanoscale Pd particle distributions in MCM-41, i.e. in the mesopores and on the external surface, were obtained by using a siliceous MCM-41 and a silylated MCM-41 (S-MCM-41) as the starting support materials, respectively. The electron density of Pd in Pd/S-MCM-41 was lower than that in Pd/MCM-41. Pd/S-MCM-41 exhibited much better selective hydrogenation performance but a lower hydrogenolysis activity than Pd/MCM-41. These differences are related to the different Pd particle distributions in MCM-41 and S-MCM-41, demonstrating that the performance of noble metal catalysts is tunable by simply controlling the nanoscale metal particle distribution in the pores.
- Dong, Chao,Li, Xiang,Wang, Anjie,Chen, Yongying,Liu, Haiou
-
-
Read Online
- Nickel and cobalt phosphides as effective catalysts for oxygen removal of dibenzofuran: Role of contact time, hydrogen pressure and hydrogen/feed molar ratio
-
The catalytic activity of nickel and cobalt phosphides, with a metal loading of 5 wt.%, supported on silica was investigated in the hydrodeoxygenation reaction (HDO) of dibenzofuran (DBF) as a model oxygenated compound at different contact times, H2 pressures and H2/DBF molar ratios. The aim of the study was to understand the mechanism of the reaction and to study the impact of H2 pressure and H2/DBF molar ratio on the reaction. The catalysts were characterized by N2 adsorption-desorption isotherm measurement at -196°C, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), CO chemisorption, NH3 Temperature-Programmed Desorption (NH3-TPD), IR spectroscopy and H2 Temperature-Programmed Desorption (H2-TPD). The prepared catalysts were tested in the HDO reaction of DBF in a continuous-flow fixed-bed stainless steel catalytic reactor at pressures ranging from 1-30 bar at 275°C. The results obtained indicate that the Ni2P catalyst is more active than the CoP catalyst, converting more than 90% of DBF at the highest contact time into oxygen-free products. The activity of both catalysts increases with increased contact time. At low contact times, the intermediates tetrahydrodibenzofuran (THDBF) and hexahydrodibenzofuran (HHDBF) are observed as products, while an increment in the contact time led to the transformation of THDBF and HHDBF into O-free compounds, mainly bicyclohexane (BCH), indicating that the HDO of DBF follows the path: DBF → HHDBF → THDBF → 2-CHP → BCH. Further, both Ni2P and CoP catalysts are active at medium pressures with HDO degrees similar to those obtained at 30 bar. Ni2P is less affected by the changes in H2/DBF ratio than CoP and the catalysts are more active at high H2/DBF molar ratios.
- Infantes-Molina,Gralberg,Cecilia,Finocchio, Elisabetta,Rodríguez-Castellón
-
-
Read Online
- Effective hydrodeoxygenation of dibenzofuran by a bimetallic catalyst in water
-
Effective hydrodeoxygenation (HDO) of dibenzofuran (DBF) catalyzed by a bimetallic nickel/platinum (Ni/Pt) catalyst in water was demonstrated at 200 °C and 1.2 MPa hydrogen (H2) pressure. The bimetallic catalysts prepared by a wet chemical method exhibit prominent activity that overcomes the limitations of use of a single Ni or Pt metal catalyst. The yield of HDO products can be up to 90%. Reaction results indicate that the conversion of DBF was affected by the reaction temperature and H2 pressure. The deoxygenation selectivity was strongly dependent on reaction temperature. The reaction pathway is also proposed.
- Dong, Peng,Lu, Guo-Ping,Cai, Chun
-
-
Read Online
- Promising Ni/Al-SBA-15 catalysts for hydrodeoxygenation of dibenzofuran into fuel grade hydrocarbons: Synergetic effect of Ni and Al-SBA-15 support
-
This work has been undertaken with the aim of designing promising noble-metal-free catalysts for efficient hydrodeoxygenation (HDO) of dibenzofuran (DBF) into fuel grade hydrocarbons. For this, various Ni/Al-SBA-15 catalysts with different Si/Al (50, 60, 70 and 80) mole ratios were synthesized and their catalytic performance was tested for HDO of DBF in a batch reactor. The catalysts were systematically characterized using XRD, N2-adsorption-desorption, Raman, H2-TPR, NH3-TPD, XRF, and FESEM techniques. The activity results showed that the HDO of DBF proceeds via hydrogenation of benzene on the Ni sites followed by cleavage of C-O bonds on the acidic sites of the catalyst to yield unsaturated hydrocarbons. Further hydrogenation of unsaturated hydrocarbons on the Ni sites gives bicyclohexane as the major product. Remarkably, a 100% DBF conversion was found for all the catalysts except for Ni/SBA-15 and Ni/Al-SBA-15(80) (Si/Al mole ratio = 80) catalysts, which showed 97.97 and 99.31%, respectively. A significant observation noticed in this study is that the incorporation of Al into Ni/SBA-15 results in an outstanding improvement in the selectivity of the bicyclohexane product. Among the catalysts tested, the Ni/Al-SBA-15(50) (Si/Al mole ratio = 50) catalyst showed the highest efficiency, with superior selectivity of ~87% for bicyclohexane and ~96% degree of deoxygenation at 10 MPa, 260 °C and 5 h. The obtained structure-activity results reveal the synergetic effect of Ni and support in HDO of DBF reaction: the concentration of acidic sites has a significant effect on the selectivity of the desired products.
- Gbadamasi, Sharafadeen,Ali, Tammar Hussein,Voon, Lee Hwei,Atta, Abdulazeez Yusuf,Sudarsanam, Putla,Bhargava, Suresh K.,Abd Hamid, Sharifah Bee
-
-
Read Online
- Cu/Mg/Al/Zr non-noble metal catalysts for o-phenylphenol synthesis
-
Cu/Mg/Al/Zr hydrotalcite-like precursors with Zr4+:(Al3+ + Zr4+) atomic ratios between 0 and 1 were prepared by co-precipitation methods. The precursors were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (TG) analysis and Fourier transform infrared spectroscopy (FT-IR). The results confirmed that well-defined layered double hydroxides (LDH) can be synthesized when the added Zr content is less than 0.25 in terms of Zr4+/(Al3+ + Zr4+) atomic ratio. The catalysts of Cu/Zn/Al/Zr mixed oxides can be obtained via thermal decomposition of hydroxide precursors, and can be used in dehydrogenation of 2-(1-cyclohexenyl) cyclohexanone (CHCH) to ortho-phenylphenol (OPP). Copper particles inside the catalyst act as active sites for dehydrogenation. Transmission electron microscopy (TEM), XRD, N2O chemisorption and N2 adsorption-desorption were performed to investigate the effect of Zr content on determining the copper particle size. Based on the catalytic performance test, it was concluded that the conversion of CHCH depends on the copper particle size of these catalysts.
- Zeng, Yongping,Zhang, Tianchi,Xu, Yueyang,Hu, Peili,Ye, Ting,Jia, Zhehua,Ju, Shengui
-
-
Read Online
- ALKYLATION OF PHENOL WITH CYCLOHEXENE.
-
The alkylation of phenol with cyclohexene in the vapor phase has been studied over the cation-exchanged X zeolite catalysts. Because of the dealkylation of products, the catalytic activity decreased with rising reaction temperature. The yield of cyclohexy
- Seino,Okazaki,Saito
-
p. 32 - 38,32,33,34,37
(1976)
-
Read Online
- Supported Pt-Ni bimetallic nanoparticles catalyzed hydrodeoxygenation of dibenzofuran with high selectivity to bicyclohexane
-
Catalytic hydrodeoxygenation (HDO) is one of the most effective methods to upgrade the oxygen-containing compounds derived from coal tar to valuable hydrocarbons. Herein, an efficient bimetallic catalyst Pt1Ni4/MgO was prepared and applied in the HDO of dibenzofuran (DBF). High yield (95%) of the desired product bicyclohexane (BCH) was achieved at 240 °C and 1.2 MPa of H2. Superior catalytic performance could be ascribed to the “relay catalysis” of Pt sites and Ni sites, and the reaction pathway is proposed as well. Scale-up experiment and recyclability test were also performed, which demonstrated the recyclability and promising potential application of Pt1Ni4/MgO.
- Cai, Chun,Wu, Pengyu
-
supporting information
(2021/07/10)
-
- Nanocrystalline hierarchical ZSM-5: An efficient catalyst for the alkylation of phenol with cyclohexene
-
In this paper, authors report the synthesis of nanocrystalline hierarchical zeolite ZSM-5 and its application as a heterogeneous catalyst in the alkylation of phenol with cyclohexene. The catalyst was synthesized by vacuum-concentration coupled hydrothermal technique in the presence of two templates. This synthetic route could successfully introduce pores of higher hierarchy in the zeolite ZSM-5 structure. Hierarchical ZSM-5 could catalyse effectively the industrially important reaction of cyclohexene with phenol. We ascribe the high efficiency of the catalyst to its conducive structural features such as nanoscale size, high surface area, presence of hierarchy of pores and existence of Lewis sites along with Br?nsted acid sites. The effect of various reaction parameters like duration, catalyst amount, reactant mole ratio and temperature were assessed. Under optimum reaction conditions, the catalyst showed up to 65% selectivity towards the major product, cyclohexyl phenyl ether. There was no discernible decline in percent conversion or selectivity even when the catalyst was re-used for up to four runs. Kinetic studies were done through regression analysis and a mechanistic route based on LHHW model was suggested.
- Radhika,Selvin, Rosilda,Kakkar, Rita,Roselin, L. Selva
-
p. 5404 - 5413
(2018/02/28)
-
- Enantiospecific sp2–sp3 Coupling of ortho- and para-Phenols with Secondary and Tertiary Boronic Esters
-
The coupling of ortho- and para-phenols with secondary and tertiary boronic esters has been explored. In the case of para-substituted phenols, after reaction of a dilithio phenolate species with a boronic ester, treatment with Ph3BiF2 or Martin's sulfurane gave the coupled product with complete enantiospecificity. The methodology was applied to the synthesis of the broad spectrum antibacterial natural product (?)-4-(1,5-dimethylhex-4-enyl)-2-methyl phenol. For ortho-substituted phenols, initial incorporation of a benzotriazole on the phenol oxygen atom was required. Subsequent ortho-lithiation and borylation gave the coupled product, again with complete stereospecificity.
- Wilson, Claire M.,Ganesh, Venkataraman,Noble, Adam,Aggarwal, Varinder K.
-
supporting information
p. 16318 - 16322
(2017/12/04)
-
- Iron-catalyzed arene alkylation reactions with unactivated secondary alcohols
-
A simple, iron-based catalytic system allows for the inter- and intramolecular arylation of unactivated secondary alcohols. This transformation expands the substrate scope beyond the previously required activated alcohols and proceeds under mild reaction conditions, tolerating air and moisture. Furthermore, the use of an enantioenriched secondary alcohol provides an enantioenriched product for the intramolecular reaction, thereby offering a convenient approach to nonracemic products.
- Jefferies, Latisha R.,Cook, Silas P.
-
supporting information
p. 2026 - 2029
(2014/05/06)
-
- Hexagonal zirconium phosphate nanoparticles as an efficient and recyclable catalyst for selective solvent-free alkylation of phenol with cyclohexanol
-
A facile synthesis of hexagonal α-zirconium phosphate (ZP) nanoparticles as an effective, eco-friendly and recyclable solid acid catalyst was studied. Polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) were used as the organic matrix which were the dispersing agents and acted as a template for the nanoparticles. It seems H-bonds between ZP and PVA or PVP along polymer chains lead to a better dispersion of in situ formed ZP. Pure ZP nanoparticles with hexagonal shape were obtained after calcination of PVA/ZP or PVP/ZP. The catalysts were characterized by several physico-chemical techniques such as BET, ICP-OES, XRD, FT-IR, SEM and TEM. The TPD-NH3 analysis suggests the presence of a reasonable amount of Br?nsted acid sites. The acidic properties were studied in the alkylation of phenol with cyclohexanol under solvent-free conditions which produced 2-cyclohexylphenol (2-CP), 4-cyclohexylphenol (4-CP) and 2,4-dicyclohexylphenol (2,4-DCP). This alkylation reaction was also performed over P2O5/Al2O 3, P2O5/SiO2, α-ZrP (prepared in the absence of the polymers) and various ionic liquids using cyclohexanol and cyclohexene as the alkylating agents. When the hexagonal ZP nanoparticles were used as the catalyst, under optimized reaction conditions, excellent conversion of phenol and selectivity toward 4-CP were obtained. The catalyst was recovered easily from the reaction mixture, regenerated and reused at least four times without significant loss in its catalytic activity.
- Hajipour, Abdol Reza,Karimi, Hirbod
-
-
- Chemoselective O-Versus C-Alkylation of substituted phenols with cyclohexene over mesoporous ZSM-5
-
Chemoselective O- versus C-alkylation of substituted phenols such as phenol, p-cresol, and guaiacol with cyclohexene were investigated over various ZSM-5 catalysts with different degree of mesoporosity and external acidity such as mesoporous ZSM-5 synthesized by microwave induced assembly via electrostatic interaction between sulfonic acid, functionalized or non-functionalized ZSM-5 nanozeolites and counter cationic surfactant, and hydrothermal synthesized microporous ZSM-5 with or without sulfonic acid functionalization and surfactant. The selectivity of O- and C-alkylated products varied with different degree of mesoporosity. The selectivity of C-alkylated products increased with increasing mesopore volume and external acid sites, whereas that of O-alkylated product decreased. The mesoporous ZSM-5 synthesized under microwave via sulfonic acid functionalization showed not only the highest mesoporosity and external acid sites but also the best catalytic activity and selectivity of C-alkylated products, whereas the other ZSM-5 catalysts mainly produced O-alkylated products due to diffusion limitation of bulky product.
- Jin, Hailian,Ansari, Mohd Bismillah,Park, Sang-Eon
-
p. 184 - 190
(2014/02/14)
-
- Titanium salalen catalysts based on cis-1,2-diaminocyclohexane: Enantioselective epoxidation of terminal non-conjugated olefins with H 2O2
-
Terminal, non-conjugated olefins, such as 1-octene, are difficult to epoxidize asymmetrically. Ti salalen complexes based on cis-1,2- diaminocyclohexane catalyze this demanding reaction giving high yields and enantioselectivities (up to 95 % ee), with H2O2 as the oxidant. The X-ray structures of the μ-oxo and peroxo complexes shed light on the coordination behavior of this novel class of ligands.
- Berkessel, Albrecht,Guenther, Thomas,Wang, Qifang,Neudoerfl, Joerg-M.
-
supporting information
p. 8467 - 8471
(2013/09/02)
-
- Acid catalyzed alkylation of phenols with cyclohexene: Comparison between homogeneous and heterogeneous catalysis, influence of cyclohexyl phenyl ether equilibrium and of the substituent on reaction rate and selectivity
-
The reactivity of several phenols toward liquid phase alkylation with cyclohexene in the presence of heterogeneous and homogeneous acid catalyst at 358 K is studied. The comparison between Amberlyst 15 and CH3SO 3H, as examples of heterogeneous and homogeneous systems, shows a higher activity of the former with different behavior of selectivity between the two systems, anyway, in both systems O-alkylation and ring alkylations occur. A remarkable difference in the selectivity of the ring alkylation between heterogeneous and homogeneous systems is observed: Amberlyst 15 shows a constant ortho/para ratio close to 2, while in the presence of CH3SO 3H ortho/para is variable from 3 to 5, suggesting an involvement of the cyclohexyl phenyl ether rearrangement. This is proved also by a direct relationship between the ortho/para ratio and the concentration of the cyclohexyl phenyl ether when CH3SO3H is used as a catalyst. The formation of cyclohexyl aryl ethers is reversible; on the contrary, ring alkylation appears irreversible. The reactivity of the dimethylphenols shows a strong influence of the steric hindrance of the substituent on the electrophilic attack of the cyclohexyl cation, which is poorly influenced by the inductive effect of the methyl group.
- Ronchin,Vavasori,Toniolo
-
scheme or table
p. 134 - 141
(2012/03/09)
-
- Kinetics and mechanism of acid catalyzed alkylation of phenol with cyclohexene in the presence of styrene divinylbenzene sulfonic resins
-
The kinetics of phenol cyclohexylation catalyzed by sulfonic resins is studied taking into account equilibria and side reactions observed in the reaction media. The influence of different sulfonic resins has been tested and only small variation of the catalyst activity, referred to the acid amount, has been observed. Besides, the selectivity is unaffected by varying the type of the catalyst. The effect of reagent concentration on the reaction rate has been also studied, together with the reactivity of the cyclohexyl phenyl ether as intermediate. The etherification equilibrium of cyclohexyl phenyl ether has been analyzed in the presence of methanesulfonic acid, and the adsorption equilibria on a sulfonic resin of reagents and intermediates are measured, too. Starting from the evidences obtained from these studies an Eley-Rideal type kinetic model has been proposed and the fitting of the experimental data allows obtaining the kinetic constant of each stage. Good reliability of the model with the experimental data has been observed, also at high conversion, and the values of the fitting parameters are substantially constant by varying the operative variable, which is a further proof of the goodness of the model.
- Ronchin,Quartarone,Vavasori
-
experimental part
p. 192 - 203
(2012/03/09)
-
- Starbon acids in alkylation and acetylation reactions: Effect of the Broensted-Lewis acidity
-
Various Starbon supported solid acids were prepared and investigated in two test reactions, namely the acetylation of 5-acetyl-methylsalicylate and the alkylation of phenol with cyclohexene. Starbon-SO3H materials exhibited in general an optimum balance of Lewis and Bronsted acid sites, making them ideal catalysts for the investigated processes. Starbon acids were comparably active and differently selective compared to similar solid acids utilised in the proposed acid catalysed processes including commercial sulphated zirconia and beta zeolite. Materials were also highly reusable under the different reaction conditions, preserving their activities almost unchanged after 4 reuses.
- Luque, Rafael,Budarin, Vitaly,Clark, James H.,Shuttleworth, Peter,White, Robin J.
-
experimental part
p. 1471 - 1476
(2012/07/03)
-
- DEHYDROGENATION OF CYCLOHEXANONE TO PRODUCE PHENOL
-
In a process for the dehydrogenation of cyclohexanone to produce phenol, a feed comprising cyclohexanone is contacted with a dehydrogenation catalyst under dehydrogenation conditions comprising a temperature of less than 4000C and a pressure of less than 690 kPa, gauge, such 0.1 to 50 wt% of the cyclohexanone in said feed is converted to phenol and the dehydrogenation product contains less than 100 ppm by weight of alkylbenzenes.
- -
-
Page/Page column 23; 25
(2011/09/14)
-
- Zirconia-modified superacid UDCaT-5: An efficient and versatile catalyst for alkylation reactions under solvent-free conditions
-
UDCaT-5, a modified version of zirconia, efficiently catalyzes alkylation of phenols with alcohols under environmentally safe, heterogeneous reaction conditions with high selectivity and in excellent yields. The high content present in UDCaT-5 with preservation of tetragonal phase of zirconia was responsible for the superactivity. Several phenolic compounds carrying either electron-sulfer releasing or electron-withdrawing substituents in the ortho, meta, and para positions afforded high yields of the products. Copyright Taylor & Francis Group, LLC.
- Yadav, Ganapati D.,Pathre, Ganesh S.
-
p. 2684 - 2691
(2008/12/22)
-
- Cyclohexylation of phenol over a solid acid catalyst comprising 12-tungstophosphoric acid and hydrous zirconia
-
The Friedel-Crafts alkylation (cyclohexylation of phenol with cyclohexene) has been carried out over 12-tungstophosphoric acid supported on hydrous zirconia under mild conditions. The catalyst shows high activity and selectivity for 2-cyclohexyl phenol, an important product used as intermediate in dyestuff preparation as well as in preparation of 2-phenyl phenol which is used as disinfectant and fungicide. In addition, the catalyst can be recycled and reused.
- Bhatt, Nikunj,Patel, Anjali
-
p. 387 - 389
(2008/09/20)
-
- ALKYLATION OF HYDROXYARENES WITH OLEFINS, ALCOHOLS AND ETHERS IN IONIC LIQUIDS
-
Hydroxyarenes are alkylated using an ionic liquid catalyst system with olefins, alcohols, or ethers as alkylating agents. The ionic liquid catalyst system comprises chloroindate (III) anions. The reactions may be conducted at moderate temperatures and pressures to yield commercially relevant alkylated hydroxyarene compounds.
- -
-
Page/Page column 18-19
(2008/06/13)
-
- Synthesis of cyclohexylphenols
-
Catalytic alkylation of phenols with cyclohexanol gives o- and p-cyclohexylphenols as the major products. The effect of temperature, catalyst nature, and reactant concentration on the reaction outcome was studied.
- Postnova,Koshel',Lebedeva,Kuznetsova,Koshel'
-
p. 1415 - 1417
(2007/10/03)
-
- Scandium(III) triflate immobilised in ionic liquids: a novel and recyclable catalytic system for Friedel-Crafts alkylation of aromatic compounds with alkenes
-
Scandium(III) triflate catalysed Friedel-Crafts alkylation of aromatic compounds with alkenes proceeded readily in the hydrophobic ionic liquid solvents based on 1,3-dialkylimidazolium salts with easy catalyst/solvent recycling, whereas these reactions did not occur in common organic solvents, water or hydrophilic ionic liquids at all.
- Song, Choong Eui,Shim, Woo Ho,Roh, Eun Joo,Choi, Jung Hoon
-
p. 1695 - 1696
(2007/10/03)
-
- Alkylation of phenol with olefins in the presence of lignosulfonic acids
-
Alkylation of phenol with cyclohexene, 1-octene, dicyclopentadiene, 1,3-cyclopentadiene, and butylene polymer distillate at 100-140°C was studied. The process was performed in the presence of lignosulfonic acids obtained from industrial calcium lignosulfonates.
- Pisanenko,Smirnov-Zamkov
-
p. 1655 - 1657
(2007/10/03)
-
- New 4-aminoquinoline Mannich base antimalarials. 1. Effect of an alkyl substituent in the 5'-position of the 4'-hydroxyanilino side chain
-
A new series of 4-aminoquinoline Mannich base derivatives have been synthesized, in which the 3'-diethylamino function of amodiaquine (AQ) is replaced by a 3'-tert-butylamino group and an aliphatic hydrocarbon entity is incorporated into the 5'-position of the 4'-hydroxyanilino side chain. Seven alkyl Mannich base derivatives were screened and found to be active against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum in vitro. The propyl and isopropyl alkyl derivatives were found to be the most active; consequently these derivatives were tested against a nonsensitive strain of Plasmodium berghi in vivo and found to be 3-fold more active than AQ, irrespective of the route of administration (oral or intraperitoneal).
- Raynes, Kaylene J.,Stocks, Paul A.,O'Neill, Paul M.,Park, B. Kevin,Ward, Stephen A.
-
p. 2747 - 2751
(2007/10/03)
-
- Regioselective alkylation of phenol with cyclopentanol over montmorillonite K10: An efficient synthesis of l-(2-cyclopentylphenoxy)-3-[(l,l-dimethylethyl)amino]propan-2-ol {(S')-penbutolol}
-
Regioselective alkylation of phenol with cyclopentanol is achieved over Montmorillonite K10 clay, producing 2-cycIopentylphenol, the key intermediate. The synthesis of optically active (S)-penbutoIol 1, an important antihypertensive drug, is realized in 5 steps from 2-cyclopentylphenol by employing Sharpless asymmetric dihydroxylation. The Royal Society of Chemistry 1999.
- Phukan, Prodeep,Sudalai, Arumugam
-
p. 3015 - 3018
(2007/10/03)
-
- Acidity effect in the regiochemical control of the alkylation of phenol with alkenes
-
Treatment of 1:1 mixtures of phenol and linear alkenes in the presence of an acidic promoter in CHCl3 at room temperature results in ortho-regioselective monoalkylation producing sec-alkylphenols in 48-60% yield. In similar reactions, branched alkenes lead exclusively to the corresponding para-tert-alkylphenols in 80-85% yield. Addition of increasing amounts of potassium phenolate to the reacting system reduces the protic acidity and promotes ortho-regioselective tert-alkylation. These results are tentatively explained in terms of competition of 'H-bond-template' and 'charge-controlled' mechanisms.
- Sartori, Giovanni,Bigi, Franca,Maggi, Raimondo,Arienti, Attilio
-
p. 257 - 260
(2007/10/03)
-
- Metal cation-exchanged montmorillonite (Mn+-mont)-catalysed aromatic alkylation with aldehydes and ketones
-
The alkylation of aromatic compounds with aldehydes and ketones in the presence of a variety of metal cation-exchanged montmorillonites (Mn+-mont; Mn+ = Zr4+, Al3+, Fe3+, Zn2+, H+, Na+) has been investigated. Al3+- and Zr4+-Monts are revealed to be effective as catalysts, while no reaction takes place with Na+-mont. Al3+-Mont-catalysed alkylation of phenol with several aldehydes produces mainly or almost solely the corresponding gem-bis(hydroxyphenyl)alkanes (bisphenols) in good yields, while that with several ketones affords selectively the corresponding alkylphenols in moderate to good yields. The alkylation always occurs at the carbonyl carbon without any skeletal rearrangement and the kind of products depends much on the steric hindrance of an electrophilic intermediary carbocation. The alkylation of anisole, veratrole and p-cresol proceeds well, while that of toluene, benzene, chlorobenzene and nitrobenzene scarcely occurs.
- Tateiwa, Jun-Ichi,Hayama, Ei,Nishimura, Takahiro,Uemura, Sakae
-
p. 1923 - 1928
(2007/10/03)
-
- Non-catalyzed C-alkylation of phenols with cyclic secondary alkyl bromides
-
C-Alkylations of phenol with 1-chloro and 1-bromoadamantane, 2-bromoadamantane, cyclohexyl bromide and exo-2-bromonorbornane, and C-alkylations of para-substituted phenol derivatives with 2-bromoadamantane are described.
- Arredondo, Yolanda,Moreno-Manas, Marcial,Pleixats, Roser
-
p. 3885 - 3895
(2007/10/03)
-
- CONVERSION OF DIMERIC PRODUCT OF CYCLOHEXANONE CONDENSATION ON ALUMINOMETALLIC CATALYSTS
-
The possibility of preparing 2-phenylphenol by catalytic dehydrogenation of 2-(cyclohexen-1-yl)-cyclohexanone was studied.Conversions of initial and intermediate compounds on alumina and aluminoplatinum and aluminopalladium catalysts at 100-375 deg C were examined for clarifying the mechanism of this reaction.
- Gorchakova, E. N.,Sibarov, D. A.,Fedorov, V. S.,Proskuryakov, V. A.
-
p. 1291 - 1295
(2007/10/02)
-
- Rearrangement Alkyl Phenyl Ethers to Alkylphenols in the Presence of Cation-exchanged Montmorillonite (Mn+-Mont)
-
The rearrangement of alkyl phenyl ethers such as 4-phenoxybutan-2-one 1, 1-phenoxybutane 2a, 2-phenoxybutane 2b, 2-methyl-2-phenoxypropane 2c and phenoxycyclohexane 2d have been investigated in the presence of cation-exchanged montmorilonite (Mn+-mont; Mn+ = Zr4+, Al3+, Fe3+ and Zn2+).The ether 1 rearranged to 4-(4-hydroxyphenyl)butan-2-one 3 (raspberry ketone), the odour source of rasprerry, in 16-34percent GLC yield, where Zn2+-mont was the most effective catalyst.Similarly, other ethers 2a-d rearranged to the corresponding alkylphenols in up to 75percent isolated yield with good product selectivity, Al3+-mont being the catalyst of choice.Al3+-Mont was regenerated and resulted in the rearrangement of 2b, 2c and 2d.
- Tateiwa, Jun-ichi,Nishimura, Takahiro,Horiuchi, Hiroki,Uemura, Sakae
-
p. 3367 - 3372
(2007/10/02)
-
- Equilibria for the isomerization of (secondary-alkyl)phenols and cyclohexylphenols
-
Equilibria of a series of isomerizations and trans-alkylations of alkylphenols have been investigated in the liquid phase over a wide range of temperatures.Equilibria of isomerizations connected with the displacement of a substituent on a benzene nucleus were studied for secondary-butyl, -amyl, -hexyl, and cyclohexyl-phenols, and di-(secondary-butyl)phenols.Equilibria of positional isomerization connected with the displacement of an oxyphenyl radical in an alkyl chain were investigated for oxyphenyl-pentanes, -hexanes, -octanes, and -decanes.Trans-alkylation was investigated for di- and tri-(secondary-butyl)phenols.Values of ΔrH0m and ΔrS0m were found for all investigated reactions.An analysis was made of the thermodynamic quantities for the reactions.Enthalpies of formation of isopropylphenols (IPP) in the gaseous state were calculated.The values of ΔfH0m/(kJ * mol-1) were found at 298.15 K: o-IPP, -(175.3 +/- 2.4); p-IPP, -(175.3 +/- 2.4); m-IPP, -(175.3 +/-2.4); 2,4-di-IPP, -(254.1 +/- 2.8); 2,5-di-IPP, -(254.1 +/- 2.8); 2,6-di-IPP, -(254.1 +/- 2.8); 3,5-di-IPP, -(254.1 +/- 2.8); 2,4,6-tri-IPP, -(333.0 +/- 3.1).
- Nesterova, T. N.,Pimerzin, A. A.,Rozhnov, A. M.,Karlina, T. N.
-
p. 385 - 396
(2007/10/02)
-
- ALKYLATION OF PHENOL BY ALCOHOLS IN THE PRESENCE OF ALUMINUM PHENOLATE
-
The reaction of phenol with alcohols in the presence of aluminum phenolate leads to a mixture of 2- and 4-alkylphenols, of which the former predominate in the case of benzyl, tert-butyl, and cyclohexyl alcohols, and the latter in the case of dimethylphenyl- and diphenylmethylcarbinols.Only triphenyl(4-hydroxyphenyl)methane is formed during the alkylation of phenol by triphenylcarbinol.In individual experiments the formation of small amounts of alkyl phenyl ethers and 2,6-dialkylphenols was observed.
- Koshchii, V. A.,Kozlikovskii, Ya. B.,Matyusha, A. A.
-
p. 1358 - 1361
(2007/10/02)
-
- Preparation of diphenolics
-
A process for the production of diphenolic compounds having a divalent bridge. A first disubstituted phenol is reacted with an aldehyde in the presence of a secondary amine and excess alcohol to form an ether intermediate. The ether intermediate is reacted with a phenol having an open ortho or para position to form a diphenolic.
- -
-
-
- Hydroalkylation of Phenol to Cyclohexylphenyl in the Presence of Pd-Al2O3 and NaCl-AlCl3 under Hydrogen Pressure
-
The hydroalkylation of phenol (1) in the presence of palladium catalyst and fused salt (NaCl-AlCl3) under hydrogen pressure was carried out.By using 1percent Pd-Al2O3 (1g) and the fused salt (1:1 mol ratio, 6g), 4-cyclohexyphenol (6) was obtained selectively from 1 (30g) in a yield of 31.9 percent at 120 deg C for 4.5 h.Cyclohexylphenols were formed by way of 2-cyclohexen-1-ol and 1.Keywords-hydroalkylation; palladium catalyst; fused salt; phenol; 2-cyclohexylphenol; 4-cyclohexylphenol; 2-cyclohexylcyclohexanone
- Kamiyama, Tsutomu,Enomoto, Saburo,Inoue, Masami
-
p. 450 - 454
(2007/10/02)
-
- KINETICS AND MECHANISM OF THE ALKYLATION OF PHENOL WITH CYCLOHEXENE IN THE PRESENCE OF ALUMINUM PHENOLATE
-
The kinetics of the alkylation of phenol with cyclohexene in the presence of aluminum phenolate was studied.A mechanism is proposed for the ortho-alkylation of phenols by olefins, involving the intermediate formation of the ion pair -R+ at a steady concentration.The ion pair is transformed into the o-alkylphenol in the controlling stage.The alkylation rate of phenol is higher that that of 2-cyclohexylphenol, and this is due to the determining effect of the entropy factor.
- Kozlikovskii, Ya. B.,Koshchii, V. A.,Chernyaev, B. V.
-
p. 909 - 913
(2007/10/02)
-
- Process for the selective production of dihydroxybenzenes
-
The known nuclear hydroxylation of phenol or substituted phenols or phenol ethers with organic solutions of hydrogen peroxide in the presence of a catalyst is carried out in improved manner by employing both (1) a special, practically water free solution of hydrogen peroxide in an organic solvent which forms an azeotrope with water, which azeotrope boils below the boiling point of hydrogen peroxide, and (2) selenium dioxide as a catalyst. Through this, the nuclear hydroxylation is substantially simpler than previously. Besides, for the first time, it is possible to control the ortho to para ratio or the two ortho ratios to each other.
- -
-
-
- REACTION OF PHENOL WITH CYCLOHEXENE IN THE PRESENCE OF ALUMINUM PHENOLATE
-
The reaction of phenol with cyclohexene in the presence of aluminum phenolate leads to a mixture of mono-, di-, and tricyclohexylphenols, in which the ortho-alkylation products predominate.Conditions were found (molar ratio of phenol, cyclohexene, and catalyst 1.0:2.1:0.1, temperature 200 deg C, reaction time 8 h) under which the yield of the desired product (2,6-dicyclohexylphenol) amounted to 65percent.
- Kozlikovskii, Ya. B.,Koshchii, V. A.
-
p. 108 - 111
(2007/10/02)
-
- REACTION OF PHENOL WITH CYCLOHEXANONE IN THE PRESENCE OF ALUMINUM PHENOLATE
-
The reaction of phenol with cyclohexanone in the presence of aluminum phenolate leads to a mixture of products of ether and phenolic character and also a mixture of the dimer and trimer of the initial ketone.As a rule 1-(2-hydroxyphenyl)cyclohexene predominates in the mixture.
- Kozlikovskii, Ya. B.,Chernyaev, B. V.
-
p. 1970 - 1973
(2007/10/02)
-
- Polycyclic phenols, alcohols and ketones from phenols, cyclic alcohols and cyclic ketones using a nickel oxide/manganese oxide/magnesium oxide catalyst in presence of at least one of hydrogen and nitrogen
-
At least one of a polycyclic phenol, a polycyclic alcohol and a polycyclic ketone is produced under hydrogenation conditions using a nickel oxide/manganese oxide/magnesium oxide catalyst by subjecting at least one of a monocyclic ketone, a monocyclic alcohol and a monocyclic phenol to said conditions and said catalyst.
- -
-
-
- Conversion of alkyl and aryl hydroxy compounds producing aldehyde, alcohol and ketone using manganese oxide/nickel oxide/magnesium oxide catalysts
-
Alkyl and aryl hydroxy compounds are converted to aldehydes, alcohols, and ketones in the presence of hydrogen using a catalyst comprised of the oxides of manganese, nickel and magnesium.
- -
-
-
- Synthesis and Structure-Activity Relationships among α-Adrenergic Receptor Agonists of the Phenylethanolamine Type
-
Nineteen arylethanolamine derivatives related to norepinephrine were prepared and tested for α-adrenergic stimulant activity.In one series the analogues possess a p-hydroxy function, while the meta position is substituted by methyl, ethyl, isopropyl, cyclohexyl, fluoro, chloro, iodo, carboxy, carbomethoxy, and methylsulfamido groups.The other series is meta hydroxylated with the para position substituted by the same groups.The influence of these groups upon the α-adrenergic activity is discussed, and the compounds are compared to octopamine, normetanephrine,norepinephrine, and norphenylephrine.It has been found that the introduction of an isopropyl, cyclohexyl, and fluoro group in the meta position of octopamine improves its affinity by three, five, and six times, respectively, whereas when these groups are introduced in the para position of norphenylephrine their effects are always detrimental.The most active compound, α-(aminomethyl)-(4-fluoro-3-hydroxyphenyl)methanol (44), has about one-hundreth the affinity and the same intrinsic activity as norepinephrine.
- Leclerc, Gerard,Bizec, Jean Claude,Bieth, Nicole,Schwartz, Jean
-
p. 738 - 744
(2007/10/02)
-
- Phenol transalkylation process
-
Phenols having an unsubstituted ortho position are transalkylated in the ortho position by mixing them with an ortho-alpha-branched alkylphenol (e.g., 2,6-di-sec-butylphenol) and an aluminum phenoxide catalyst and heating the mixture to 100°-350°C., preferably in a closed system and in the presence of olefin corresponding in structure to the ortho-alpha-branched alkyl group.
- -
-
-