181-28-2Relevant academic research and scientific papers
Phosphorus promoted SO42-/TiO2 solid acid catalyst for acetalization reaction
Zhong, Shaofeng,Ou, Qiongrong,Shao, Linjun
, p. 3005 - 3008 (2015/11/27)
A novel phosphorus modifed SO42-/TiO2 catalyst was synthesized by a facile coprecipitation method, followed by calcination. The catalytic performance of this novel solid acid was evaluated by acetalization. The results showed that the phosphorus was very effcient to enhance the catalytic activity of SO42-/TiO2. The solid acid owned high activity for the acetalization with the yields over 90%. Moreover, the solid acid could be reused for six times without loss of initial catalytic activities.
Preparation of a novel solid acid catalyst with Lewis and Bronsted acid sites and its application in acetalization
Du, Yijun,Shao, Linjun,Luo, Lingyan,Shi, Si,Qi, Chenze
, p. 157 - 163 (2014/02/14)
A novel melamine-formaldehyde resin (MFR) supported solid acid with Lewis and Bronsted acid sites was synthesized through the immobilization of acidic ionic liquid and cuprous ion on MFR. The scanning electron microscopy (SEM) characterization showed that addition of PEG-2000 in the synthesis of MFR could promote the formation of regular particles with diameters around 3.7 μm. The XRD pattern demonstrated that some cuprous ions were aggregated. The catalytic performance of this acid catalyst was evaluated by acetalization. The results showed that the catalytic activity of MFR with Bronsted acid could be improved by addition of Lewis acid. The solid acid was very efficient for the acetalization of carbonyl compounds and diols with moderate to excellent yields and there was no loss of catalytic activity even after being recycled for 6 runs. TUeBITAK.
Synthesis of a novel melamine-formaldehyde resin-supported ionic liquid with Bronsted acid sites and its catalytic activities
Xing, Guiying
, p. 1369 - 1374 (2013/10/01)
Bronsted acidic ionic liquid immobilized on a melamine-formaldehyde resin (AIL-MFR) was synthesized through the reaction of melamine-formaldehyde resin (MFR) with 1,4-butanesulfonate. Using PEG-2000 as the additive, the MFR can be prepared in regular microspheres with an average diameter of 3.97 μm and surface area of 9.09 m2 g-1. The AIL-MFR had high acidity of 2.93 mmol g-1, mainly from the sulfonic groups. The catalysis results showed that the AIL-MFR had high activity and stability for acetalization with excellent conversions and yields for most substrates. Furthermore, immobilization of the acidic ionic liquid on the MFR made the recycling of the catalyst convenient.
Sulfonic groups functionalized preoxidated polyacrylonitrile nanofibers and its catalytic applications
Shao, Linjun,Xing, Guiying,He, Luyao,Chen, Ji,Xie, Hangqing,Liang, Xuezheng,Qi, Chenze
, p. 133 - 137 (2015/04/15)
A SO3H-bearing nanofiber mat was synthesized and investigated as a novel heterogeneous acid catalyst. Preoxidated polyacrylonitrile nanofiber mat was prepared via electrospinning and heat treatment, and then reacted with chlorosulfuric acid to introduce the sulfonic groups. The nanofiber mat owned high acidity of 2.99 mmol/g. The preoxidation and sulfonation were examined by FT-IR spectroscopy, elemental analysis and X-ray diffraction spectroscopy (XRD). The fiber morphologies were characterized by scanning electron microscopy (SEM). The catalytic activities and reuse of the prepared nanofiber mat solid acid catalyst have been evaluated for the acetalization and esterification. The regular fiber mat structure could significantly facilitate the recovery and reuse of the catalyst. The excellent catalytic performance and easy recycling made the novel fiber mat solid acid hold great potential for the green chemical processes.
Self-assembly synthesis of a high-content sulfonic acid group functionalized ordered mesoporous polymer-based solid as a stable and highly active acid catalyst
Wang, Wei,Zhuang, Xin,Zhao, Qingfei,Wan, Ying
supporting information; body text, p. 15874 - 15886 (2012/09/05)
A stable and highly active ordered mesoporous polymer-based acid catalyst has been prepared via a simple surfactant templating approach and oxidation treatment. The composition and nanostructure are characterized by XRD, NMR, XPS, TEM, nitrogen sorption, elemental and chemical analysis. The sulfonic acid groups have been anchored within the well-arranged channels of the polymer-based matrix. Even with a high -SO3H group loading (up to about 27.4 wt%) on the mesoporous polymer-based material, the ordered mesostructure and high surface area (～400 m2 g-1) can be retained and the functional moieties are highly chemically accessible. With the large number of acid sites (0.93-2.38 H+ mmol g-1 determined by acid-base titration) and the hydrophobic character, the mesoporous polymer-based solid exhibits unique catalytic performance in acid-catalyzed reactions such as condensation and acetalization, not only high activity (per site yield of bisphenol-A is over 45 in the condensation of phenol and acetone) but also excellent stability. Loss in acidic loading and activity is negligible even after the catalyst is reused 20 times in the acetalization of butanediol and aldehyde. The stability is most likely attributed to the hydrophobic nature of the mesoporous polymer-based solids, which favors the diffusion of water and thereby inhibits the poisoning of acidic sites caused by water generating in the reaction. Moreover, with large mesopores, the diffusion of reactants and products can be promoted and hence the catalytic activity can be further increased.
Synthesis of a novel multi-SO3H functionalized ionic liquid and its catalytic activities
Xudong, Sun,Huiquan, Xiao,Yijun, Du,Jingjing, Zhang,Xuezheng, Liang,Chenze, Qi
, p. 301 - 305 (2012/10/29)
A novel multi-SO3H functionalized ionic liquid is synthesized and a detailed account of its cata- lytic activities in acetalization and acetylation is given. The results showed that the ionic liquid is very efficient in the conventional acid-catalyzed reactions with good to excellent yields within a short reaction time. Oper- ational simplicity, small amounts required, low cost of the catalyst, high yields, scalability and reusability are the key features of this methodology, which indicates the high potentialities of the novel ionic liquid to be used in environmentally friendly processes. Pleiades Publishing, Ltd., 2012.
Correlation between 13C and 17O chemical shifts and torsional strain in spiroacetals
Guerrero-Alvarez, Jorge Antonio,Ariza-Castolo, Armando
, p. 795 - 798 (2007/10/03)
The relationship between the 13C and 17O NMR chemical shifts and the dihedral energies (non-bonding interactions) of 1,4-dioxaspiro[4.4]nonane, 1,4-dioxa- and 6,10-dioxaspiro[4.5]decane, 1,4-dioxa- and 6,11-dioxaspiro[4.6]undecane, 1,5-dioxaspiro[5.5]undecane, 1,5-dioxa and 7,12-dioxaspiro[5.6]dodecane and 1,6-dioxaspiro[6.6]tridecane were analyzed. These data showed correlation of the non-bonding interactions with the chemical shift of the spiranic carbon, as well as a linear relationship between 13C and 17O.
Application of Functional Ionic Liquids Possessing Two Adjacent Acid Sites for Acetalization of Aldehydes
Li, Dongmei,Shi, Feng,Peng, Jiajian,Guo, Shu,Deng, Youquan
, p. 3582 - 3585 (2007/10/03)
Several acid functional ionic liquids, in which cations possess two adjacent acid sites, were synthesized and used for the acetalization of aldehydes with good catalytic performance under mild reaction conditions.
An efficient procedure for the preparation of cyclic ketals and thioketals catalyzed by zirconium sulfophenyl phosphonate
Curini,Epifano,Marcotullio,Rosati
, p. 1182 - 1184 (2007/10/03)
A convenient method for the preparation of cyclic ketals and thioketals using zirconium sulfophenyl phosphonate as catalyst is described.
5. Formation of cyclic ketals from hydroxyalkyl enol ethers, a stereoelectronically controlled endo-trig-cyclizatitm process
Deslongchamps, Pierre,Dory, Yves L.,Li, Shigui
, p. 41 - 50 (2007/10/03)
Acid-catalyzed cyclic ketal formation vs. hydrolysis of a series of hydroxyalkyl cyclic enol ethers in the presence of 1 equiv. of H2O, and acid-catalyzed cyclic-ketal formation (same ketals as above) vs. methanolysis of a series of mixed pent-4-enyl hydroxyalkyl ketals with N-bromosuccinimide in the presence of 4 equiv. of MeOH led to the same result: the intramolecular cyclization processes occur at similar rates as the intermolecular H2O or MeOH attacks independently of the size of the rings formed (five-, six-, or seven-niembered), by cyclizations. These results can be explained by the facts that, due to stereoelectronic effects which impose a torsional strain to the sp2 hybridized O-atom, the cyclization activation enthalpy decreases, as the length of the hydroxyalkyl chain increase (ease of cyclization: 7 > 6 > 5), whereas the entropy factor favors the cyclization in the reverse fashion (ease of cyclization: 5 > 6 > 7). The various reaction pathways have been examined using the semi-empirical Hamiltonian AM1, and the results obtained confirm that large-ring formation is enthalpically much favored over the cyclization processes leading to small rings (ease of cyclization: 7 > 6 > 5).
