6314-97-2Relevant articles and documents
One-pot Synthesis of Acetals by Tandem Hydroformylation-acetalization of Olefins Using Heterogeneous Supported Catalysts
Li, Xiao,Qin, Tingting,Li, Liusha,Wu, Bo,Lin, Tiejun,Zhong, Liangshu
, p. 2638 - 2646 (2021/01/05)
Abstract: A green route for one?pot synthesis of acetals by tandem hydroformylation?acetalization of olefins using supported Rh?based?catalysts was developed. Experimental results demonstrated that suitable Rh loading (1 wt%) with appropriate reaction temperature (120?°C) and reaction time (8?h) were favorable for the formation of acetals, and a high acetals selectivity of 94.6% was achieved. More importantly, the selectivity to valuable linear products was enhanced in this tandem catalysis. Based on the catalytic mechanism study, highly dispersed RhOx nanoparticles and abundant acid sites on the supports were responsible for the hydroformylation and acetalization, respectively. Graphical abstract: One-pot synthesis of acetals directly from olefins with high selectivity was achieved over heterogeneous bifunctional catalysts via tandem hydroformylation-acetalization. [Figure not available: see fulltext.]
METHOD OF FORMING MONOMERS AND FURFURAL FROM LIGNOCELLULOSE
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Page/Page column 23; 24, (2020/06/05)
The present disclosure relates to a method of producing monophenolicmonomers and furfural from lignocellulosic biomass beating the biomass in a solvent together with a zeolite based catalyst.
Silver-Catalyzed Olefination of Acetals and Ketals with Diazoesters to β-Alkoxyacrylates
Li, Jiawen,Qian, Bo,Huang, Hanmin
supporting information, p. 7090 - 7094 (2018/11/23)
The first silver-catalyzed reaction of acetals or ketals with diazoesters leading to trisubstituted or tetrasubstituted β-alkoxyacrylates is now reported. A broad range of acetals and ketals bearing different substituents is compatible with this protocol and thus provides an attractive approach for the synthesis of complex β-alkoxyacrylates. The power of this method was further demonstrated by the successful synthesis of picoxystrobin, which is one of the most popular agricultural fungicides commercialized by Dupont.
Decomposition of a Β-O-4 lignin model compound over solid Cs-substituted polyoxometalates in anhydrous ethanol: acidity or redox property dependence?
Wu, Xuezhong,Jiao, Wenqian,Li, Bing-Zheng,Li, Yanming,Zhang, Yahong,Wang, Quanrui,Tang, Yi
, p. 1216 - 1228 (2017/07/10)
Production of aromatics from lignin has attracted much attention. Because of the coexistence of C–O and C–C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone (2-PAP), was investigated over several cesium-exchanged polyoxometalate (Cs-POM) catalysts. Decomposition of 2-PAP can follow two different mechanisms: an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox properties of the catalysts. The catalysts of POMs perform the following functions: promoting active hydrogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen liberation and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP (>99%) with excellent selectivities to the desired products (98.6% for phenol and 91.1% for acetophenone) can be achieved.
Antimony(v) catalyzed acetalisation of aldehydes: An efficient, solvent-free, and recyclable process
Ugarte, Renzo Arias,Hudnall, Todd W.
, p. 1990 - 1998 (2017/06/09)
A highly selective, solvent-free process for the acetalisation of aldehydes was achieved by the use of a readily accessible antimony(v) catalyst which we previously prepared in our lab as a tetraarylstibonium triflate salt ([1][OTf]). High yields of the acetals were achieved in the presence of stoichimetric amounts of either triethoxymethane or triethoxysilane. It was found that triethoxymethane reactions required longer time to reach completion when compared to triethoxysilane reactions which were completed upon mixing of the reagents. The products can be easily separated from the catalyst by distillation which enabled further use of [1][OTf] in additional calytic reactions (up to 6 cycles). Moreover, [1]+ also catalyzed the deprotection of the acetals into their corresponding aldehydes using only water as a solvent.
Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow
Lyons,Crocker,Enders,Nguyen
supporting information, p. 3993 - 3996 (2017/09/08)
Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. Herein we demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.
Cleavage of the lignin β-O-4 ether bond: Via a dehydroxylation-hydrogenation strategy over a NiMo sulfide catalyst
Zhang, Chaofeng,Lu, Jianmin,Zhang, Xiaochen,Macarthur, Katherine,Heggen, Marc,Li, Hongji,Wang, Feng
supporting information, p. 6545 - 6555 (2018/06/06)
The efficient cleavage of lignin β-O-4 ether bonds to produce aromatics is a challenging and attractive topic. Recently a growing number of studies have revealed that the initial oxidation of CαHOH to CαO can decrease the β-O-4 bond dissociation energy (BDE) from 274.0 kJ mol-1 to 227.8 kJ mol-1, and thus the β-O-4 bond is more readily cleaved in the subsequent transfer hydrogenation, or acidolysis. Here we show that the first reaction step, except in the above-mentioned pre-oxidation methods, can be a Cα-OH bond dehydroxylation to form a radical intermediate on the acid-redox site of a NiMo sulfide catalyst. The formation of a Cα radical greatly decreases the Cβ-OPh BDE from 274.0 kJ mol-1 to 66.9 kJ mol-1 thereby facilitating its cleavage to styrene, phenols and ethers with H2 and an alcohol solvent. This is supported by control experiments using several reaction intermediates as reactants, analysis of product generation and by radical trap with TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) as well as by density functional theory (DFT) calculations. The dehydroxylation-hydrogenation reaction is conducted under non-oxidative conditions, which are beneficial for stabilizing phenol products.
A generalized approach for iron catalyzed chemo- and regioselective formation of anti-Markovnikov acetals from styrene derivatives
Chowdhury, Abhishek Dutta,Lahiri, Goutam Kumar
supporting information; experimental part, p. 3448 - 3450 (2012/05/20)
Fe(BF4)2·6H2O in the presence of pyridine-2,6-dicarboxylic acid and PhI(OAc)2 can efficiently catalyze the formation of chemoselective dialkyl acetals from styrene derivatives with anti-Markovnikov regioselectivity in good to high yields under mild and benign reaction conditions.
Synthesis of chiral acetals by asymmetric selenenylations
Uehlin, Lars,Wirth, Thomas
experimental part, p. 1374 - 1385 (2010/03/03)
Asymmetric selenenylations of (E)-ethoxystyrene are described leading to chiral acetals. An efficient synthesis of such compounds including the determination of their absolute configuration is described.
Effective Au(III)-CuCl2-catalyzed addition of alcohols to alkenes
Zhang, Xin,Corma, Avelino
, p. 3080 - 3082 (2008/02/10)
Alkenes can be activated by Au(III) catalysts, and the effective addition of alcohols to alkenes can be carried out under mild conditions with Au(III), provided that catalytic amounts of CuCl2 are added, which significantly stabilize the cationic Au(III). The Royal Society of Chemistry.
