2568-30-1Relevant articles and documents
Polyesters by a Radical Pathway: Rationalization of the Cyclic Ketene Acetal Efficiency
Gigmes, Didier,Gil, Noémie,Guillaneuf, Yohann,Lefay, Catherine,Plummer, Christopher M.,Siri, Didier,Tardy, Antoine
supporting information, p. 14517 - 14526 (2020/07/13)
Radical ring-opening polymerization (rROP) of cyclic ketene acetals (CKAs) combines the advantages of both ring-opening polymerization and radical polymerization thereby allowing the robust production of polyesters coupled with the mild polymerization conditions of a radical process. rROP was recently rejuvenated by the possibility to copolymerize CKAs with classic vinyl monomers leading to the insertion of cleavable functionality into a vinyl-based copolymer backbone and thus imparting (bio)degradability. Such materials are suitable for a large scope of applications, particularly within the biomedical field. The competition between the ring-opening and ring-retaining propagation routes is a major complication in the development of efficient CKA monomers, ultimately leading to the use of only four monomers that are known to completely ring-open under all experimental conditions. In this article we investigate the radical ring-opening polymerization of model CKA monomers and demonstrate by the combination of DFT calculations and kinetic modeling using PREDICI software that we are now able to predict in silico the ring-opening ability of CKA monomers.
PROCESS FOR PREPARING CHLOROACETALDEHYDE ACETALS
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Paragraph 0034; 0035, (2016/10/11)
The invention relates to a process for preparing chloroacetaldehyde acetals of monohydric, dihydric or higher-functionality aliphatic alcohols, in which the chloroacetaldehyde acetal is obtained from an aqueous chloroacetaldehyde solution in the presence of the alcohol to be acetalized and an acid catalyst by azeotropic removal of water with the aid of a solvent, wherein the solvent is a halogenated solvent.
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.
Synthesis of novel solid acidic ionic liquid polymer and its catalytic activities
Liang, Xuezheng
, p. 724 - 729 (2014/01/23)
The novel solid acidic ionic liquid polymer has been synthesized through the copolymerization of acidic ionic liquid oligomers and resorcinol- formaldehyde (RF resin). The catalytic activities were investigated through the acetalization. The results showed that the PIL was very efficient for the reactions with the average yield over 99.0%. The procedure was quite simple with just one-step to complete both the reactions. The high hydrophobic BET surface, high catalytic activities and high stability gave the PIL great potential for green chemical processes. Pleiades Publishing, Ltd., 2013.
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.
Polyacrylonitrile fiber mat supported solid acid catalyst for acetalization
Shao, Linjun,Du, Yijun,Xing, Guiying,Lv, Weixi,Liang, Xuezheng,Qi, Chenze
experimental part, p. 1199 - 1203 (2012/10/07)
A novel polyacrylonitrile hybrid fiber mat supported solid acid catalyst was prepared by electrospin-ning, and its catalytic activities were carefully investigated through acetalization reactions. The results showed that this hybrid fiber mat exhibits high activity for the reactions, with average yields over 95%. Besides having catalytic activities similar to the solid acid, the heterogeneous solid acid/polyacrylonitrile mat can be reused in six runs without significant loss of catalytic activities. The large size of the hybrid fiber mat greatly facilitates recovery of the catalyst from the reaction mixture. The high and stable catalytic activities of the hybrid fiber mat hold great potential for green chemical processes and preparation of membrane reactors in the future.
Synthesis of a novel ionic liquid with both Lewis and Br?nsted acid sites and its catalytic activities
Liang, Xuezheng,Qi, Chenze
experimental part, p. 808 - 812 (2012/01/04)
The novel ionic liquid with both Lewis and Br?nsted acid sites has been synthesized and its catalytic activities for acetalization and Michael addition were investigated carefully. The novel ionic liquid was stable to water and could be used in aqueous solution. Furthermore, the molar ratio of the Lewis and Br?nsted acid sites could be adjusted according to different reactions. The results showed that the novel ionic liquid was very efficient for the traditional acid-catalyzed reactions with good to excellent yields in short time.
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.
