F:Flammable;
123-63-7Relevant academic research and scientific papers
Liquid Phase Reaction of Acetaldehyde over Various ZSM-5 Zeolites
Mori, Hidemitsu,Yamazaki, Tatsuya,Ozawa, Sentaro,Ogino, Yoshisada
, p. 2498 - 2504 (1993)
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.
Tandem reactions of Friedel-Crafts/aldehyde cyclotrimerization catalyzed by an organotungsten Lewis acid
Wang, Hsing-Shiun,Yu, Shuchun Joyce
, p. 1051 - 1055 (2002)
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.
Synthesis of antimalarial 1,2,4-trioxanes via photooxygenation of a chiral allylic alcohol
Griesbeck, Axel G.,El-Idreesy, Tamer T.,Fiege, Maren,Brun, Reto
, p. 4193 - 4195 (2002)
(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.
Cooperative cluster metalation and ligand migration in zirconium metal-organic frameworks
Yuan, Shuai,Chen, Ying-Pin,Qin, Junsheng,Lu, Weigang,Wang, Xuan,Zhang, Qiang,Bosch, Mathieu,Liu, Tian-Fu,Lian, Xizhen,Zhou, Hong-Cai
, p. 14696 - 14700 (2015)
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.
Acid-catalyzed trimerization of acetaldehyde: A highly selective and reversible transformation at ambient temperature in a zeolitic solid
Harris,Thomas,Lee,Sankar,Kitchin,Dugal
, p. 1322 - 1326 (2002)
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.
A convenient solvent-free preparation of 1,3,5-trioxanes
Augé, Jacques,Gil, Richard
, p. 7919 - 7920 (2002)
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.
Novel Si(II)+and Ge(II)+Compounds as Efficient Catalysts in Organosilicon Chemistry: Siloxane Coupling Reaction ?
Fritz-Langhals, Elke,Kneissl, Sotirios,Piroutek, Phillip,Werge, Sven
, (2020/09/02)
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-.
SELECTIVE REMOVAL OF IMPURITIES IN ACETIC ACID PRODUCTION PROCESSES
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Paragraph 0091, (2017/07/18)
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).
Ethylenedisalicylic acid derivatives as dual inhibitors of PTP1B and IKKβ and their antiobesity and antidiabetic effects in mice
Aher, Nilkanth G.,Park, Ji-Won,Park, Byung Ho,Kim, Chan Kyung,Han, Inn-Oc,Cho, Hyeongjin
, p. 855 - 863 (2016/06/14)
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.
Paraldehyde preparation method
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Paragraph 0012, (2016/10/08)
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.
