- Ketalization of ketones to 1,3-dioxolanes and concurring self-aldolization catalyzed by an amorphous, hydrophilic SiO2-SO3H catalyst under microwave irradiation
-
The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10percent (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. The same catalyst can easily reverse the ketalization reaction. Printed in Brazil-
- Barbosa, Sandro L.,Ottone, Myrlene,De Almeida, Mainara T.,Lage, Guilherme L.C.,Almeida, Melina A.R.,Nelson, David Lee,Dos Santos, Wallans T.P.,Clososki, Giuliano C.,Lopes, Norberto P.,Klein, Stanlei I.,Zanatta, Lucas D.
-
p. 1663 - 1671
(2018/06/29)
-
- A containing-SO 3 H acidic magnetic material catalytic preparing acetal (ketone) method
-
The invention discloses a method for preparing acetal (ketone) by catalyzing an acidic magnetic material containing -SO3H, which belongs to the technical field of chemical material and preparation thereof. According to the invention, mol ratio of aldehyde or ketone to alcohol used in the preparation method is 1: (1-5), mole of the acidic magnetic material catalyst accounts for 8-10% of that of the used aldehyde or ketone by calculating -SO3H, reaction temperature is 110 DEG C, the reaction time is 0.5-3 hours, the reaction pressure is one atmospheric pressure, a cooling step is carried out to room temperature after reaction is completed, the catalyst is sucked by a magnet, and the conversion rate, selectivity and acetal(ketone) yield of the reaction raw material are detected by a reaction solution through a gas chromatograph. Compared with the preparation method of other catalysts, the method has the advantages of high reaction selectivity, simple separation of the catalyst and the product, the catalyst enables cycle usage without any treatment, the operation of whole preparation process is simple, the economic benefit is high, and the method is convenient for industrial large scale production.
- -
-
Paragraph 0026
(2017/03/08)
-
- Graphene-catalyzed transacetalization under acid-free conditions
-
1,2- and 1,3-Diols are readily protected as cyclic acetals and ketals through a graphene-catalyzed transacetalization process. The methodology features an atom economic procedure since quasi-stoichiometric conditions have been developed. Unlike prior systems, the graphene-catalyzed transacetalization is performed under Br?nsted and Lewis acid-free conditions and without solvent. Our method has been applied to several volatile compounds that are unsuitable for complex work-up and extensive purification steps. The very unusual catalytic properties of graphene for transacetalization reactions are ascribed to molecular charge transfer between graphene and substrates.
- Nongbe, Medy C.,Oger, Nicolas,Ekou, Tchirioua,Ekou, Lynda,Yao, Benjamin K.,Le Grognec, Erwan,Felpin, Fran?ois-Xavier
-
p. 4637 - 4639
(2016/09/23)
-
- Phosphorus promoted SO42-/TiO2 solid acid catalyst for acetalization reaction
-
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
-
p. 3005 - 3008
(2015/11/27)
-
- Synthesis of a novel melamine-formaldehyde resin-supported ionic liquid with Bronsted acid sites and its catalytic activities
-
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.
- Xing, Guiying
-
p. 1369 - 1374
(2013/10/01)
-
- Synthesis of novel solid acidic ionic liquid polymer and its catalytic activities
-
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
-
p. 724 - 729
(2014/01/23)
-
- Polyacrylonitrile fiber mat supported solid acid catalyst for acetalization
-
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.
- Shao, Linjun,Du, Yijun,Xing, Guiying,Lv, Weixi,Liang, Xuezheng,Qi, Chenze
-
experimental part
p. 1199 - 1203
(2012/10/07)
-
- Indium(III) triflate catalysed transacetalisation reactions of diols and triols under solvent-free conditions
-
Acyclic acetals and ketals undergo transacetalisation in the presence of catalytic quantities of indium(III) triflate (In(OTf)3) and diols or triols under solvent-free conditions to generate the corresponding cyclic acetals and ketals in excellent yield. The methodology has been further developed to encompass a tandem acetalisation-acetal exchange protocol, which provides a facile and high yielding route to cyclic ketals from unreactive ketones under very mild reaction conditions.
- Smith, Brendan M.,Kubczyk, Tomasz M.,Graham, Andrew E.
-
p. 7775 - 7781
(2012/09/21)
-
- Synthesis of a novel ionic liquid with both Lewis and Br?nsted acid sites and its catalytic activities
-
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
-
experimental part
p. 808 - 812
(2012/01/04)
-
- Indium triflate mediated tandem acetalisation-acetal exchange reactions under solvent-free conditions
-
Acyclic acetals and ketals undergo exchange reactions in the presence of catalytic quantities of indium(III) triflate and diols to generate the corresponding cyclic acetals and ketals in excellent yield. The protocol is rapid, employs mild conditions and can be adapted to employ solvent-free reaction conditions. We have further developed this methodology to encompass a tandem acetalisation-acetal exchange protocol which provides facile access to cyclic ketals from unreactive ketones also under very mild, solvent-free reaction conditions.
- Smith, Brendan M.,Graham, Andrew E.
-
experimental part
p. 6281 - 6283
(2011/12/14)
-
- Chemoselective and chemospecific protection and deprotection of a carbonyl group using polystyrene divinylbenzene sulfonic acid
-
Chemospecific protection of one carbonyl group of two identical carbonyls of 2,2-dialkyl-1,3-cyclohexanedione and chemoselective protection of aliphatic or aromatic carbonyls in the presence of conjugated carbonyl compounds using cross-linked polystyrene divinyl benzene sulfonic acid (SPS) as a heterogeneous catalyst has been demonstrated. Copyright
- Verma, Sanjeev K.,Sathe, Manisha,Kaushik
-
experimental part
p. 1701 - 1707
(2010/07/15)
-
- Acid catalysed reaction of estrones with neopentyl glycol under forced conditions
-
Upon reaction with an excess of 2,2-dimethylpropane-1,3-diol (neopentyl glycol) under acid catalysis, estrones form 17-O-[2',2'-dimethyl-2'-(5", 5"-dimethyl-1",3"-dioxanyl)ethyl] substituted estra-3,17β-diols. The reaction represents a formal reduction of a keto function under acidic conditions in the absence of a metal.
- Oliveira, Cristina,Morais, Goreti Ribeiro,Imai, Masao,Inohae, Eiko,Yamamoto, Chishou,Mataka, Shuntaro,Thiemann, Thies
-
body text
p. 158 - 162
(2010/08/06)
-
- 3,3,9,9-Tetramethyl-1,5,7,11-tetraoxaspiro[5.5]undecane as a reagent for protection of carbonyl compounds
-
3,3,9,9-Tetramethyl-1,5,7,11-tetraoxaspiro[5.5]undecane is introduced as a new, stable and chemoselective reagent for the protection of aldehydes and ketones under mild reaction condition in high yield.
- Rahimizadeh, Mohammad,Bakavoli, Mehdi,Shiri, Ali,Eshghi, Hossein,Saberi, Sattar
-
experimental part
p. 704 - 706
(2009/09/25)
-
- Indium triflate mediated acetalization of aldehydes and ketones
-
Aldehydes and ketones are rapidly transformed into either acyclic or cyclic acetals at room temperature in high yields and in very short reaction times using catalytic quantities of indium triflate, in contrast to previous reports.
- Smith, Brendan M.,Graham, Andrew E.
-
p. 9317 - 9319
(2007/10/03)
-
- An efficient procedure for protection of carbonyls in Br?nsted acidic ionic liquid [Hmim]BF4
-
Protection of carbonyls as acetals or ketals using Br?nsted acidic ionic liquid [Hmim]BF4 as catalyst as well as solvent was investigated. Satisfactory results were obtained for the protection of carbonyls as cycloacetals or ketals with diols. The product can be separated conveniently from the reaction system, and the ionic liquid can be reused after removal of water.
- Wu, Hai-Hong,Yang, Fan,Cui, Peng,Tang, Jie,He, Ming-Yuan
-
p. 4963 - 4965
(2007/10/03)
-
- Acetonyltriphenylphosphonium bromide and its polymer-supported analogues as catalysts for the protection of carbonyl compounds as acetals or thioacetals
-
Both acetonyltriphenylphosphonium bromide (ATPB) and poly-p-styryldiphenylacetonylphosphonium bromide (PATPB) are excellent catalysts in the protection of aldehydes as acetals or thioacetals. In general, ATPB is highly selective as ketones do not give good yields of ketals with this catalyst.
- Hon, Yung-Son,Lee, Chia-Fu,Chen, Rong-Jiunn,Huang, Yi-Fen
-
p. 2829 - 2842
(2007/10/03)
-
- Synthesis and stereochemistry of substituted 1,3-dioxa-2-Silacyclohexanes. V. Substituted 2-chloro-1,3-dioxa-2-silacyclohexanes
-
The possibility of synthesis of alkyl(phenyl)-2-chloro-1,3-dioxa-2-silacyclohexanes from the corresponding 1,3-dioles and chlorosilanes was shown. The influence of reaction conditions and the structure of the starting reagents on the yield of silicon-containing acetals was demonstrated. The reaction of the obtained compounds with aldehydes and ketones, resulting in substituted 1,3-dioxanes, was studied. The structure of the resulting compounds was proved by NMR spectroscopy.
- Gvozdik,Gal'chenko,Musavirov
-
p. 784 - 787
(2007/10/03)
-
- Efficient Synthesis of Acetals Promoted by a Yttria-Zirconia Based Strong Lewis Acid Catalyst
-
A variety of carbonyl compounds react with 2,2-dimethylpropane-1,3-diol in the presence of a catalytic amount of a novel yttria-zirconia based strong Lewis acid to afford the corresponding acetals in excellent yields.
- Pals, Godwin C. G.,Keshavaraja,Saravanan,Kumar, Pradeep
-
p. 426 - 427
(2007/10/03)
-
- N-(arylmethyl)-2-(or -4)-cyanopyridinium hexafluoroantimonates as new useful catalysts for acetalization of carbonyl compounds
-
Carbonyl compounds 1 were converted to the corresponding 1,3-dioxolanes 2 and 1,3-dioxanes 4 with ethylene glycol and 2,2-dimethyl-1,3-propandiol, respectively, in the presence of 1-3 mol% of N-(benzyl, 4-methylbenzyl or 4-methoxybenzyl)-2(or -4)cyanopyridinium hexafluoroantimonates 3. The catalyst 3d was also effective for the tetrahydropyranylation.
- Lee,Lee,Takata,Endo
-
p. 368 - 370
(2007/10/02)
-