- Polyesters by a Radical Pathway: Rationalization of the Cyclic Ketene Acetal Efficiency
-
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.
- Gigmes, Didier,Gil, Noémie,Guillaneuf, Yohann,Lefay, Catherine,Plummer, Christopher M.,Siri, Didier,Tardy, Antoine
-
supporting information
p. 14517 - 14526
(2020/07/13)
-
- PROCESS FOR PREPARING CHLOROACETALDEHYDE ACETALS
-
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.
- -
-
Paragraph 0034; 0035
(2016/10/11)
-
- 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)
-
- Preparation of a novel solid acid catalyst with Lewis and Bronsted acid sites and its application in acetalization
-
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.
- Du, Yijun,Shao, Linjun,Luo, Lingyan,Shi, Si,Qi, Chenze
-
p. 157 - 163
(2014/02/14)
-
- 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)
-
- Sulfonic groups functionalized preoxidated polyacrylonitrile nanofibers and its catalytic applications
-
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.
- Shao, Linjun,Xing, Guiying,He, Luyao,Chen, Ji,Xie, Hangqing,Liang, Xuezheng,Qi, Chenze
-
p. 133 - 137
(2015/04/15)
-
- 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)
-
- 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)
-
- Application of Functional Ionic Liquids Possessing Two Adjacent Acid Sites for Acetalization of Aldehydes
-
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.
- Li, Dongmei,Shi, Feng,Peng, Jiajian,Guo, Shu,Deng, Youquan
-
p. 3582 - 3585
(2007/10/03)
-
- Depolymerization of chloroaldehyde cyclic trimers
-
A method for producing high purity chloroaldehyde monomers at a high yield by depolymerization of a chloroaldehyde cyclic trimer represented by the following formula, STR1 wherein R is a hydrogen atom, methyl group, or an ethyl group. The depolymerization reaction can be carried out in the presence of activated clay. Said chloroaldehyde cyclic trimer can be stored in a stable manner and chloroaldehyde monomers obtained by the depolymerization can be used as are as a raw material for the synthetic reaction of chloroaldehyde derivatives.
- -
-
-
- One-pot Preparation of 2-Chloromethyldioxolanes and 2-Aminothiazoles from Chloromethyltrioxanes
-
Thermal degradation of chloromethyltrioxanes in the presence of catalytic amount of montmorillonite clay generated α-chloroaldehydes with high purity, which were treated in situ with ethylene glycol or thiourea to afford 2-chloromethyldioxolanes and 2-aminothiazoles, respectively.The clay catalysts used were removed by filtration.
- Wakasugi, Takashi,Miyakawa, Tadashi,Suzuki, Fukuichi,Itsuno, Shinichi,Ito, Koichi
-
p. 2039 - 2042
(2007/10/02)
-
- Preparation of racemic and enantiomerically pure cyclic ketene acetals
-
Cyclic ketene acetals have been prepared from a-haloaldehyde dimethylacetals by transacetalization and subsequent elimination in PTC without solvent conditions. No racemization has been observed when an enantiomerically pure diol has been used. Stability and storage conditions have been studies.
- Diaz-Ortiz,Diez-Barra,De La Hoz,Prieto
-
p. 1935 - 1942
(2007/10/02)
-
- Process of producing chloroacetals
-
A process of producing a high-pure acyclic or cyclic chloroacetal with a good yield by a simple step of reacting a monochloroacetaldehyde trimer or a monochloacetaldehyde monomer obtained by heating the trimer in the existence of an acid catalyst and a monohydric or dihydric alcohol having from 1 to 5 carbon atoms in the existence of an acid catalyst or a dehydrating agent.
- -
-
-
- Process for producing 2-halomethyl-1,3-cyclic acetal
-
The yield and purity of 2-halomethyl-1,3-cyclic acetals is improved by subjecting the reaction product of 1,2-dihaloethyl acetate and aliphatic diol to alkaline hydrolysis. The resulting aqueous and organic phases are separated and the organic phase distilled to recover the 2-halomethyl-1,3-cyclic acetal product.
- -
-
-
- Aminosulfonylthiadiazolylureas
-
Disclosed are compounds of the formula STR1 wherein R1 is alkyl, R2 is selected from the group consisting of hydrogen and alkyl; or R1 and R2 together with the nitrogen atom form a cyclic ring structure having 4 or 5 carbon atoms; m is the integer 0 or 1; when m is 1, R4 and R5 are each independently selected from the group consisting of hydrogen and alkyl or up to 3 carbon atoms; when m is 0, R4 is hydrogen and R5 is the same as defined above; R3, R6, R7, R8, R9 are each independently selected from the group consisting of hydrogen and alkyl; n is an integer from 0 to 2; and Z1 and Z2 are each independently selected from the group consisting of oxygen and sulfur. These compounds are useful as herbicides.
- -
-
-
- Formation and Structure of 1,1-Dialkoxyalkene Radical Cations in Aqueous Solution. An in situ Electron Spin Resonance and Pulse Conductivity Study
-
The radical cations (1), (10), (11a and b), and (12)-(15) have been produced in aqueous solution and have been identified by e.s.r. spectroscopy and conductivity investigation.The open chain radical cations exist in Z,E-configurations.They exhibit two sets of aδH couplings.The larger couplings were assigned to the protons in groups with the Z-configuration.In all cases the radical spin is located mainly at the carbon atoms.Under our conditions radical (13) disappeared pseudo-monomolecularly upon reaction with water (k = 7 x 1E3 s-1) whereas the other radical cations are longer lived and decayed bimolecularly with diffusion controlled rates.The radical cations were generated from open chain or cyclic acetals bearing Br, Cl, or CH3CO2 groups β to the acetal CH group, e.g. (CH3O)2CH-CH2Cl or (CH2O)2CH-CH2Cl.These substrates were subjected to hydrogen abstraction by OH. or SO4.- radicals or triplet acetone in aqueous solution.Hydrogen abstraction from the acetal CH group led to radicals which undergo fast heterolytic dissociation into radical cations and leaving group anions, e.g. (CH3O)2C.-CH2CCl --> (CH3)2C+-C.H2 + Cl(1-).
- Behrens, Guenter,Bothe, Eberhard,Koltzenburg, Guenther,Schulte-Frohlinde, Dietrich
-
p. 883 - 889
(2007/10/02)
-
- Dioxane substituted-α-haloanilides as herbicides
-
This invention discloses new compounds of the formula EQU1 wherein Y is selected from the group consisting of hydrogen, lower alkyl and halogen; R1 is selected from the group consisting of hydrogen, lower alkyl and lower alkoxy; R2 is lower alkyl; R3, R4, R5, R6 and R7 are independently selected from the group consisting of hydrogen and lower alkyl; X is halogen; m is an integer from 0 to 2; Z1 and Z2 are independently selected from the group consisting of oxygen and sulfur; and n is an integer from 1 to 2. The compounds of the above description are useful as herbicides.
- -
-
-
- N-alpha-chloroacetyl-n-(1,3-dioxolan-2-ylmethyl)-2-ethyl-6-methylaniline
-
This invention discloses the compound N-α-chloroacetyl-N-(1,3-dioxolan-2-ylmethyl)-2-ethyl-6-methylaniline and its utility as a herbicide.
- -
-
-
- Heterocyclic thiadiazolylureas
-
This invention discloses new compounds of the formula EQU1 wherein R1 is selected from the group consisting of alkyl, alkenyl, haloalkyl, cycloalkyl, alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl; Z1 and Z2 are independently selected from the group consisting of oxygen and sulfur; R2, R3, R4, R5, R6 and R7 are each selected from the group consisting of hydrogen and alkyl; m is an integer from 0 to 2; and n is the integer 1 or 2. The compounds of the above description are useful as herbicides.
- -
-
-
