- Liquid Phase Reaction of Acetaldehyde over Various ZSM-5 Zeolites
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Acetaldehyde reacted over various ion-exchanged ZSM-5 zeolites at 15+/-0.5 deg C under a nitrogen pressure of 1x105 Pa.The main products of the reaction were 2α,4α,6α-trimethyl-1,3,5-trioxane (cis-paraldehyde) and its isomer, 2α,4α,6β-trimethyl-1,3,5-trioxane (trans-paraldehyde).Several rare earth ZSM-5 (REZSM-5) and M/HZSM-5 (partially proton exchanged ZSM-5) catalysts exhibited high activities for trans-paraldehyde formation.The reaction appeared to proceed by the following scheme: cis-paraldehyde acetaldehyde trans-paraldehyde.A comparison of the catalytic activity with the IR intensity of acidic OH groups over the catalyst suggested that the active site for cis-paraldehyde formation was the Broensted acidic site, while the active site for trans-paraldehyde formation was a Broensted acid site in the neighborhood of an Mn+ site in the ZSM-5 zeolite pore.
- Mori, Hidemitsu,Yamazaki, Tatsuya,Ozawa, Sentaro,Ogino, Yoshisada
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- Tandem reactions of Friedel-Crafts/aldehyde cyclotrimerization catalyzed by an organotungsten Lewis acid
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The tris(2-pyridyl)phosphine complex [P(2-py)3 W(CO)(NO)2](BF4)2 acts as a Lewis acid catalyst precursor for the tandem reactions of Friedel-Crafts/aldehyde cyclotrimerization, which lead to the formation of a series of hyper-branched star polymers.
- Wang, Hsing-Shiun,Yu, Shuchun Joyce
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- Synthesis of antimalarial 1,2,4-trioxanes via photooxygenation of a chiral allylic alcohol
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(equation presented) Photooxygenation of the chiral allylic alcohol 4-methyl-3-penten-2-ol (3) in nonpolar solvents and subsequent Lewis acid-catalyzed peroxyacetalization afforded a series of monocyclic and spirobicyclic 1,2,4-trioxanes (5, 6). Two products show significant anti-Malaria activity against Plasmodium falciparum when compared with chloroquine.
- Griesbeck, Axel G.,El-Idreesy, Tamer T.,Fiege, Maren,Brun, Reto
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- Cooperative cluster metalation and ligand migration in zirconium metal-organic frameworks
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Cooperative cluster metalation and ligand migration were performed on a Zr-MOF, leading to the isolation of unique bimetallic MOFs based on decanuclear Zr6M4 (M=Ni, Co) clusters. The M2+ reacts with the μ3-OH and terminal H2O ligands on an 8-connected [Zr6O4(OH)8(H2O)4] cluster to form a bimetallic [Zr6M4O8(OH)8(H2O)8] cluster. Along with the metalation of Zr6 cluster, ligand migration is observed in which a Zr-carboxylate bond dissociates to form a M-carboxylate bond. Single-crystal to single-crystal transformation is realized so that snapshots for cooperative cluster metalation and ligand migration processes are captured by successive single-crystal X-ray structures. In3+ was metalated into the same Zr-MOF which showed excellent catalytic activity in the acetaldehyde cyclotrimerization reaction. This work not only provides a powerful tool to functionalize Zr-MOFs with other metals, but also structurally elucidates the formation mechanism of the resulting heterometallic MOFs. Mixed metal MOF: Cooperative cluster metalation and ligand migration were performed on a Zr-MOF, leading to the isolation of Zr6M4 based bimetallic MOFs (right). This strategy allows for the functionalization of Zr-MOFs with other metals for a variety of promising applications.
- Yuan, Shuai,Chen, Ying-Pin,Qin, Junsheng,Lu, Weigang,Wang, Xuan,Zhang, Qiang,Bosch, Mathieu,Liu, Tian-Fu,Lian, Xizhen,Zhou, Hong-Cai
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- Acid-catalyzed trimerization of acetaldehyde: A highly selective and reversible transformation at ambient temperature in a zeolitic solid
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Acetaldehyde underwent a reversible Bronsted acid-catalyzed cyclotrimerization reaction, with 100% selectivity, at ambient temperature within the zeolites host material ferrierite. The cyclic trimer was the only product formed in the reaction. The equilibrium proportions of acetaldehyde and the cyclic trimer at ambient temperature corresponded to a conversion > 90%. On the contrary, a broad distribution of products was obtained in the corresponding acid-catalyzed transformation of acetaldehyde in the liquid state. The reversibility of the cyclotrimerization reaction in ferrierite was confirmed from the fact that, on adsorption of a pure sample of the cyclic trimer within ferrierite, a reaction occurred to produce acetaldehyde as the only product with the same equilibrium distribution of the cyclic trimer and acetaldehyde as that realized from the reaction of acetaldehyde in ferrierite. The fact that no reaction occurred on adsorption of acetaldehyde within sodium-exchanged ferrierite confirmed the role of Bronsted acid catalysis in the transformation between acetaldehyde and the cyclic trimer in ferrierite.
- Harris,Thomas,Lee,Sankar,Kitchin,Dugal
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- A convenient solvent-free preparation of 1,3,5-trioxanes
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In the presence of a small amount of trimethylsilyl chloride, aldehydes gave at room temperature in solvent-free conditions the corresponding 1,3,5-trioxanes with good to excellent yields.
- Augé, Jacques,Gil, Richard
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- Novel Si(II)+and Ge(II)+Compounds as Efficient Catalysts in Organosilicon Chemistry: Siloxane Coupling Reaction ?
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Novel catalytically active cationic Si(II) and Ge(II) compounds were synthesized and isolated in pure form. The Ge(II)+-based compounds proved to be stable against air and moisture and therefore can be handled very easily. All compounds efficiently catalyze the oxidative coupling of hydrosil(ox)anes with aldehydes and ketones as oxidation reagents and simultaneously the reductive ether coupling at very low amounts of 0.01 mol %. Because the catalysts also catalyze the reversible cyclotrimerization of aldehydes, paraldehyde can be used as a convenient source for acetaldehyde in siloxane coupling. It is shown that the reaction is especially suitable to make siloxane copolymers. Moreover, a new fluorine-free weakly coordinating boronate anion, B(SiCl3)4-, was successfully combined with the Si(II) and Ge(II) cations to give the stable catalytically active ion pairs Cp*Si:+B(SiCl3)4-, Cp*Ge:+B(SiCl3)4-, and [Cp(SiMe3)3Ge:+]B(SiCl3)4-.
- Fritz-Langhals, Elke,Kneissl, Sotirios,Piroutek, Phillip,Werge, Sven
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- SELECTIVE REMOVAL OF IMPURITIES IN ACETIC ACID PRODUCTION PROCESSES
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Processes for producing carboxylic acid are included herein. The processes include contacting methanol and carbon monoxide in the presence of a liquid reaction medium under carbonylation conditions sufficient to form a carbonylation product including acetic acid and one or more components selected from acetaldehyde, formic acid and combinations thereof, wherein the liquid reaction medium includes: a carbonylation catalyst selected from rhodium catalysts, iridium catalysts and palladium catalysts; and water in a water concentration in a range of 1 wt.% to 14 wt.% based on the total w eight of the liquid reaction medium; and contacting at least a portion of the carbonylation product or a derivative thereof with an adsorbent at adsorption conditions sufficient to selectively reduce a concentration of one or more components present in the carbonylation product, wherein the adsorbent includes a silicoaluminophosphate (SAPO).
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Paragraph 0091
(2017/07/18)
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- Ethylenedisalicylic acid derivatives as dual inhibitors of PTP1B and IKKβ and their antiobesity and antidiabetic effects in mice
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Ethylenedisalicylic acid (EDSA) was developed as a novel scaffold for dual inhibitors of protein tyrosine phosphatase (PTP) 1B and IkB kinase β (IKKβ). EDSA is a modified version of methylenedisalicylic acid (MDSA) and contains two salicylate moieties connected by an ethylene moiety. In this study, derivatives of EDSA were synthesized and their inhibitory potencies against PTP1B and IKKβ were investigated. Many of these derivatives exhibited half-maximal inhibitory concentrations (IC50s) in the low micromolar range. The metabolic effects of ESA4, 7, and 8 were further examined in a mouse model system. ESA4 and ESA8 significantly suppressed diet-induced weight gain, whereas ESA7 had a marginal effect. ESA4, 7, and 8 also lowered fasting glucose levels and accelerated glucose clearance rates after glucose injection. These observations indicate that EDSA scaffold-based compounds are promising candidates for the treatment of obesity and diabetes.
- Aher, Nilkanth G.,Park, Ji-Won,Park, Byung Ho,Kim, Chan Kyung,Han, Inn-Oc,Cho, Hyeongjin
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p. 855 - 863
(2016/06/14)
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- Paraldehyde preparation method
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The present invention discloses a paraldehyde preparation method, which comprises: 1, adding a copper-based salt to ethanol to make the ethanol be subjected to a dehydrogenation reaction so as to obtain acetaldehyde; and 2, adding the prepared acetaldehyde to an enamel reaction pot while adding a catalyst calcium chloride to make the acetaldehyde be subjected to a polymerization reaction so as to generate the paraldehyde, wherein the polymerization reaction is performed for 14 h at a temperature of 30-35 DEG C under the effect of external circulation freezing water. According to the present invention, the paraldehyde yield is improved; the requirement on the reactor compression resistance is reduced so as to reduce the enterprise production cost; copper acetate is adopted as the precursor for producing the copper active ingredient, the selectivity of the catalytic activity is good, and the yield of the obtained paraldehyde is high; and the single food-grade ethanol is adopted as the production raw material, the whole production process is environmental pollution and pollution-free, and the sustainable ecology development is easily achieved.
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Paragraph 0012
(2016/10/08)
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- Improving the selectivity to C4 products in the aldol condensation of acetaldehyde in ethanol over faujasite zeolites
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The selective conversion of acetaldehyde to C4 products, minimizing the production of secondary (C6, C8) condensation products, could be a potential path in the production of butadiene from ethanol, a process of commercial interest. Therefore, we have investigated the selective aldol condensation of acetaldehyde in liquid phase over faujasite zeolites, NaX and NaY. Specifically, we have examined the influence of the number and location of the exchangeable cations, type of cations, and post-synthesis treatments on product selectivity. At 230 °C, NaY results in higher C4/(C6 + C8) product ratio than NaX, which can be explained in terms of the strength, density, and accessibility of basic sites, which are less favorable in NaX than NaY. In fact, the CO2 TPD measurements indicate the presence of three types of basic sites of varying strength, of which those with weak and medium strength are most important for the selective condensation. A confinement effect is observed when adding K to the NaY zeolite. The observed selectivity changes suggest that when larger cations partially occupy the supercages, the production of C8 products decreases, while C6 products increase. Also, post-synthesis washing treatments show significant variations in selectivity, which demonstrate the effects of partial occupation of the zeolite pores in the reaction. It is also shown that at a given conversion, the C4/(C6 + C8) ratio can be adjusted by modifying the micro/mesoporosity balance in the zeolite.
- Zhang, Lu,Pham, Tu N.,Faria, Jimmy,Resasco, Daniel E.
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p. 119 - 129
(2015/03/18)
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- Reactions of P(III) chlorides with aldehydes: I. Synthesis of primary intermediates of the reactions of aliphatic aldehydes with P(III) chlorides possessing electrophilic properties
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An approach to investigation of reactions of electrophilic P(III) chlorides with aliphatic aldehydes is developed. Its essence is the removal of HCl impurity from chloride and catalytic blocking of electrophilic center of the carbonyl group. For these pur
- Gazizov,Khairullin,Karimova
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p. 2281 - 2292
(2014/03/21)
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- Photocatalytic oxidation of ethanol during hydrogen generation from water-ethanol mixture over gadolinium-doped titania
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Photocatalytic hydrogen generation from water in the presence of ethanol as a sacrificial reagent was studied over gadolinium doped TiO2 photocatalyst. Photocatalytic pathways of ethanol oxidation were studied with liquid 1H NMR spectroscopy. The 1H NMR results were compared with amounts of evolved hydrogen and carbon dioxide. Acetal-dehyde, acetic acid, glycolic acid and glyoxylic acid were found as major intermediates of this process, whereas carbon dioxide evolution was the last step during ethanol photooxidation process. The mechanism of ethanol photooxidation has been proposed.
- Zalas,Gierczyk,LAniecki
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experimental part
p. 1767 - 1777
(2009/04/05)
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- InCl3 as an efficient catalyst for cyclotrimerization of aldehydes: Synthesis of 1,3,5-Trioxane under solvent-free conditions
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1,3,5-Trioxanes derived from aldehydes were synthesized using indium trichloride as a catalyst. Cyclotrimerization of the aldehydes gave excellent yields under neat conditions within a short span of time. Copyright Taylor & Francis, Inc.
- Elamparuthi,Ramesh,Raghunathan
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p. 2801 - 2804
(2007/10/03)
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- Enantioselective and regioselective nickel-catalyzed multicomponent coupling of chiral allenes, aromatic aldehydes, and silanes
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A detailed account of the development of a recently developed, nickel-catalyzed multicomponent coupling of chiral allenes, aromatic aldehydes, and silanes is described. The axial chirality of the allene is transferred completely to the product, a trisubstituted Z-allylic alcohol protected as a silyl ether. A very high preference for sp rather than sp2 coupling is observed, and differentially substituted allenes undergo highly site-selective coupling. These transformations represent the first enantioselective multi-component coupling processes of allenes.
- Ng, Sze-Sze,Jamison, Timothy F.
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p. 11405 - 11417
(2007/10/03)
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- Cyclotrimerization of Aliphatic Aldehydes Catalysed by Keggin-type Heteropoly Acids and Concomitant Phase Separation
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The acid-catalysed cyclotrimerization of aliphatic aldehydes has been examined through comparison of heteropoly acids with other acid catalysts.A Keggin-type heteropoly acid such as phosphomolybdic acid catalyses the cyclotrimerization of aldehydes, such as ethanal, propanal, butanal, 2-methylpropanal, 2,2-dimethylpropanal, hexanal, octanal, and decanal, to produce the respective 2,4,6-trialkyl-1,3,5-trioxanes in high yields.Catalysts turnover number of the heteropoly acid is more than 10000 for propanal cyclotrimerization.In addition to the high catalytic activities, the reaction mixture spontaneously separates into two phases, a produ ct phase and a catalyst phase, at high conversions of aldehyde.For propanal cycltrimerization, the reaction mixture separates into two liquid phases, and the recovered catalyst phase may be repeatedly applied to the reaction without additional care in isolation of the catalyst.The phase separation phenomenon has been concluded to be caused by the insolubility of the heteropoly acid coordinated with propanal in the product 2,4,6-triethyl-1,3,5-trioxane.
- Sato, Satoshi,Furuta, Hiromi,Sodesawa, Toshiaki,Nozaki, Fumio
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p. 385 - 390
(2007/10/02)
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- RADIATION-INITIATED ADDITION OF ACETALDEHYDE TO ALLYL ALCOHOL AND CONVERSION OF THE 1:2-TELOMER INTO 1-METHYL-2,8-DIOXABICYCLONONANE
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Radiation-initiated addition of acetaldehyde to allyl alcohol gave a mixture of 5-hydroxy-2-pentanone (1:1-aduct I), 2-methyl-2-(4-oxopentyloxy)tetrahydrofuran (II), 7-hydroxy-4-hydroxymethyl-2-heptanone (1:2-telomer III) and 1,1-bis(4-oxopentyloxy)ethane (IV).The telomer III was dehydrated to afford 3-acetonyltetrahydropyran (V), 1-methyl-2,8-dioxabicyclononane (VI) and 3,10-dimethyl-4,11,16,17-tetraoxatricyclo3,8>octadecane (VII).
- Liska, Frantisek,Fikar, Jiri,Trska, Petr,Valenta, Miroslav
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p. 3278 - 3283
(2007/10/02)
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- Acetaldehyde process
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A process for the production of an aldehyde at high selectivity and rate by the reaction of an inorganic or organic ester with carbon monoxide or synthesis gas in contact with a catalyst system containing cobalt, rhodium or ruthenium atoms and lithium iodide and, optionally, an organic ligand.
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- ALLYLSTANNATION. III. SYNTHESIS OF HOMOALLYLIC ALCOHOLS AND 4-CHLORO-2,6-DIALKYL-3-METHYLTETRAHYDROPYRANS BY REACTIONS BETWEEN (E/Z)-2-BUTENYLDICHLORO-n-BUTYLTIN AND ALDEHYDES
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2-Butenyldichloro-n-butyltin (in various cis/trans isomer ratios) reacts readily with neat RCHO (R = CH3, C2H5, (CH3)2CH, and C6H5) at 25 deg C to give (a) linear alcohols, RCH(OH)CH2CH=CHCH3 in the E and Z forms, (b) branched alcohols, RCH(OH)CH(CH3)CH=CH2 in the threo and erythro forms, and (c) 2,3,4,6-tetrasubstituted tetrahydropyrans (A) as a mixture of cis/trans isomers arising from the CH(CH3)-CHCl bond.The maximum yields of these tetrahydropyrans were obtained by the use of 3-3.5 molar ratios RCHO/tin compound in the absence of solvents, whereas work-up after reactions in CH2Cl2 gave linear alcohols as the main products.The formation of linear alcohols appears to be stereospecific, as the ratio of E/Z isomers obtained is the same as that in the organotin compound.Tetrahydropyrans are formed preferentially as the trans isomers.
- Gambaro, Alessandro,Boaretto, Andrea,Marton, Daniele,Tagliavini, Giuseppe
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p. 293 - 304
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. XIII. MECHANISM OF THE FORMATION OF THIOPHENE IN THE GAS-PHASE PYROLYSIS OF DIVINYL SULFOXIDE
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The main product of the gas-phase pyrolysis of divinyl sulfoxide at 400-450 deg C is thiophene, whose formation is due to the thermal dissociation of the intermediate vinylsulfenic acid with the elimination of the hydroxyl group.The emergent S-vinyl radical undergoes intermolecular cyclization to form thiophene, and in the presence of chlorobenzene it reacts with the latter to form benzothiophene.
- Voronkov, M. G.,Deryagina, E. N.,Sukhomazova, E. N.,Gusarova, N. K.,Efremova, G. G.,Trofimov, B. A.
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p. 1090 - 1092
(2007/10/02)
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