- (1)H NMR Investigations on the Conformation of the Spirodioxolanes Derived from Vicinal Diols II-The Ketal of Cyclohexanone and Racemic 1,2-Propanediol
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The methylene, methine and methyl protons at C- and C- from the dioxolane miety in 2-methyl-1,4-dioxaspirodecane constitute an ABMX3 coupling system.The analysis data obtained and, also, the application of the Karplus rule to the value of the J(AB) vicinal coupling constant, confirm the axial orientation of the A methine proton and the pseudoequatirial orientation of the B methylene proton.These findings agree with a 'half-chair'conformation of the 1,3-dioxolane ring.
- Csunderlik, C.,Chirila, T.,Bacaloglu, R.
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- Method for improving activity of propylene epoxide catalyst and co-producing ketal (acetal)
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The invention provides a method for synthesizing propylene epoxide and co-producing ketal (acetal) by taking a by-product PG as a raw material in propylene epoxidation in the presence of heteropoly acid as a catalyst. Negative effects of alcohol substances to the activity of the catalyst in epoxidation reaction are eliminated, the activity of the catalyst is improved, the catalyst is used stably,meanwhile, downstream application of the by-product PG is expanded, and a preparation method for ketal (acetal) is provided. The method has the advantages of gentle reaction conditions, good catalyzing stability, good catalyst using effect, and resource utilization of the by-product.
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Paragraph 0019; 0020; 0033-0036; 0040-0042
(2019/01/17)
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- Facile synthesis of acetal over a supported novel Br?nsted and lewis acid ionic liquid catalyst
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A novel Br?nsted and Lewis acid ionic liquid (IL) chlorinated butyrolactam chlorozincinate (CPCl-ZnCl2) was synthesized by a hydrothermal process and characterized by Fourier transform infrared (FT-IR). The Fe-SBA-15 mesoporous materials with different Si/Fe mole ratios were prepared by direct synthesis method. The supported ionic liquid (IL/Fe-SBA-15) with various IL contents were prepared by a wet impregnation method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N2 physical adsorption. The acidity was measured by FT-IR spectroscopy using pyridine as probes. The catalytic property was tested in acetalization of cyclohexanone with ethylene glycol. The results demonstrated that the IL/Fe-SBA-15 catalysts were of higher catalytic activity compared to Fe-SBA-15. Under optimal conditions, the acetalization could reach to 92.6% cyclohexanone conversion with 99.3% acetal selectivity. After 5 cycles, the cyclohexanone conversion decreased slightly. Also, the catalyst showed good catalytic property in the other acetalization of cyclohexanone and benzyl alcohol.
- Liu, Ruifeng,Dai, Liming,Zhao, Qian,Xie, Yingjie,Jiang, Tingshun
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p. 4396 - 4405
(2019/05/08)
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- Robust acidic pseudo-ionic liquid catalyst with self-separation ability for esterification and acetalization
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The novel acidic pseudo-ionic liquid catalyst with self-separation ability has been synthesized through the quaternization of triphenylphosphine and the acidification with silicotungstic acid. The pseudo-IL showed high activities for the esterification with average conversions over 90%. The pseudo-IL showed even higher activities for acetalization than traditional sulfuric acid. The homogeneous catalytic process benefited the mass transfer efficiency. The pseudo-IL separated from the reaction mixture automatically after reactions, which was superior to other IL catalysts. The high catalytic activities, easy reusability and high stability were the key properties of the novel catalyst, which hold great potential for green chemical processes.
- Shi, Yingxia,Liang, Xuezheng
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p. 1413 - 1421
(2019/05/04)
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- 8-Hydroxy-2-methylquinoline-modified H4SiW12O40: A reusable heterogeneous catalyst for acetal/ketal formation
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A heteropoly acid based organic hybrid heterogeneous catalyst, HMQ-STW, was prepared by combining 8-hydroxy-2-methylquinoline (HMQ) with Keggin-structured H4SiW12O40 (STW). The catalyst was characterized via elemental analysis, X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TG) and potentiometric titration analysis. The catalytic performance of the catalyst was assessed in the ketalization of ketones with glycol or 1,2-propylene glycol. Various reaction parameters, such as the glycol to cyclohexanone molar ratio, catalyst dosage, reaction temperature and time, were systematically examined. HMQ-STW exhibited a relatively high yield of corresponding ketal, with 100% selectivity under the optimized reaction conditions. Moreover, catalytic recycling tests demonstrated that the heterogeneous catalyst exhibited high potential for reusability, and it was revealed that the organic modifier HMQ plays an important role in the formation of a heterogeneous system and the improvement of structural stability. These results indicated that the HMQ-STW catalyst is a promising new type of heterogeneous acid catalyst for the ketalization of ketones.
- Liu, Li-Jun,Luan, Qing-Jie,Lu, Jing,Lv, Dong-Mei,Duan, Wen-Zeng,Wang, Xu,Gong, Shu-Wen
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p. 26180 - 26187
(2018/08/04)
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- Phosphorus promoted SO42-/TiO2 solid acid catalyst for acetalization reaction
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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.
- Zhong, Shaofeng,Ou, Qiongrong,Shao, Linjun
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p. 3005 - 3008
(2015/11/27)
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- MOR zeolite supported Bronsted acidic ionic liquid: An efficient and recyclable heterogeneous catalyst for ketalization
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In order to widen the application of ionic liquids as efficient and renewable heterogeneous catalysts, supported ionic liquids (SILs) have received considerable attention. A novel heterogeneous catalyst MOR zeolite supported Bronsted acidic ionic liquid (BAIL@MOR) was therefore prepared, characterized and applied in the ketalization reaction. The influences of reaction temperature, time, and catalyst loading have also been investigated in detail. Combined characterization results of XRD, FT-IR, SEM, TG-DTG and N 2 adsorption-desorption suggested that the BAIL [CPES-BSIM][HSO 4] was successfully immobilized on the surface of MOR zeolite by covalent bonds. Moreover, the catalytic performance tests demonstrated that the catalyst BAIL@MOR exhibited excellent catalytic activities in the ketalization of cyclohexanone with glycol, 1,2-propylene glycol and 1,3-butylene glycol under mild reaction conditions, as comparable with the homogeneous catalysis of the precursors [BSmim][HSO4] and H2SO4. In addition, the catalyst BAIL@MOR was also found to be reusable five times without a significant loss of its catalytic activity. Thus, the heterogeneous catalyst BAIL@MOR can act as a promising candidate for the ketalization reaction.
- Li, Zhang-Min,Zhou, Yan,Tao, Duan-Jian,Huang, Wei,Chen, Xiang-Shu,Yang, Zhen
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p. 12160 - 12167
(2014/03/21)
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- Synthesis of novel solid acidic ionic liquid polymer and its catalytic activities
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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.
- Liang, Xuezheng
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p. 724 - 729
(2014/01/23)
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- Synthesis of a novel multi-SO3H functionalized ionic liquid and its catalytic activities
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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.
- Xudong, Sun,Huiquan, Xiao,Yijun, Du,Jingjing, Zhang,Xuezheng, Liang,Chenze, Qi
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p. 301 - 305
(2012/10/29)
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- Synthesis of a novel ionic liquid with both Lewis and Br?nsted acid sites and its catalytic activities
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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.
- Liang, Xuezheng,Qi, Chenze
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experimental part
p. 808 - 812
(2012/01/04)
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- Preparation of salicylic acid resin supported FeCl3 lewis acid catalyst and its application in organic synthesis
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The catalytic effects of salicylic acid resin supported FeCl3 catalyst on the esterification of alcohol and carboxylic acid and on the acetalization (ketal formation) of aldehyde (ketone) and alcohol have been investigated.This catalyst is convenient to use, noncorrosive, easy to be separated from reactants and can be repeatedly used.
- Huirong, Yang,Yingde, Li Bina Cui
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p. 1233 - 1238
(2007/10/03)
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- Synthese d'acetals cycliques dans des conditions douces; Applications a l'acetalisation du chloramphenicol
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Acetalization of 1-2 and 1-3 diols, even as sterically crowded as chloramphenicol, by carbonyl derivatives with substituents of various sizes has been performed at room temperature under mild conditions, by using heterogeneous catalysis (sulfonated polystyrene) in the presence of molecular sieves.Several new acetals of chloramphenicol have thus been obtained in good yields, isolated and characterized.
- Meslard, J. C.,Subira, F.,Vairon, J. P.,Guy, A.,Garreau, R.
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- Investigation of the Effectiveness of Various 1-Dialkylamino-1-methoxycarbenium-Methyl Sulfates in the Course of Acetalization
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The rate of dimethyl ketal formation from acetone and methanol in the presence of several 1-dialkylamino-1-methoxycarbenium methyl sulfates 1a, 5a-g is studied.The fastest rate was observed in the case of 5c.In the presence of 5c, the reaction of carbonyl compounds with either methanol or 1,2-diols gave the dimethyl ketals 6 and 1,3-dioxolanes 7, respectively.
- Kantlehner, Willi,Gutbrod, Heinz-Dieter,Funke, Bernd
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p. 246 - 252
(2007/10/02)
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