- Synthesis and Hydrolysis of Chemodegradable Cationic Surfactants Containing the 1,3-Dioxolane Moiety
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In acid-catalyzed reactions of long-chain aliphatic aldehydes (Ia-d where a = n-C7H15; b = n-C9H19; c = n-C11H23; d = n-C13H27), and tridecan-7-on (Ie) with 3-chloro-1,2-propane-diol, 2-alkyl- and 2,2-dihexyl-4-chloromethyl-1,3-dioxolanes (IIa-e) were obtained.They were reacted with anhydrous dimethylamine to obtain, respectively, 2-alkyl- and dimethylamines (IIIa-e), which were quaternized with methyl bromide to obtain the desired ammonium bromides (IVa-e).The structure and purity of the compounds was proved by mass spectrometry and proton magnetic resonance spectroscopy.Additionally, trimethylammonium bromide and trimethylammonium bromide were synthesized as nonaggregating standards.Hydrolysis reactions of the synthesized ammonium bromides were performed by 0.1 M hydrochloric acid in 1:1 (vol/vol) 1,4-dioxane-water mixtures at 50, 60 and 70 deg C.Rate constants of hydrolysis reactions were determined by observing carbonyl group formation at 280 nm.The hydrolytic reactivity of the studied surfactants (IVa-c,e) was determined under unaggregated conditions.Compound IVd showed decreased reactivity.The length of the 2-alkyl group has a minor effect on rate constant values.The influence of various substituents at the C-4 atom of the 2-nonyl-1,3-dioxolan-4-yl derivatives on rate constants was also investigated. KKEY WORDS: trimethylammonium bromides, trimethylammonium bromide, chemodegradable acetal-type cationic surfactants, kinetic and thermodynamic parameters of 1,3-dioxolane ring hydrolysis.
- Wilk, Kazimiera A.,Bieniecki, Albert,Burczyk, Bogdan,Sokolowski, Adam
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- Palladium on Carbon-Catalyzed Chemoselective Oxygen Oxidation of Aromatic Acetals
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The development of an unprecedented chemoselective transformation has contributed to forming a novel synthetic process for target molecules. Chemoselective oxidation of aromatic acetals has been accomplished using a reusable palladium on carbon catalyst under atmospheric oxygen conditions to form ester derivatives with tolerance of aliphatic acetals and ketals.
- Yasukawa, Naoki,Asai, Shota,Kato, Maho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
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supporting information
p. 5604 - 5607
(2016/11/17)
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- Acetalization of aldehydes and ketones over H4[SiW 12O40] and H4[SiW12O 40]/SiO2
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H4[SiW12O40] (H-SiW12) is demonstrated to be able to efficiently catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol. Nevertheless, the possible leaching and the recycling of H-SiW12 are two major disadvantages that largely restrict its further application in industry. Moreover, H 4[SiW12O40] tends to deactivate strong proton sites due to the small surface area of 10 m2 g-1. Due to interactions with surface silanol groups, the proton sites of polyoxometalates (POMs) on SiO2 are less susceptible to deactivation. As such, immobilization of H4[SiW12O40] onto SiO 2 leads to the heterogeneous catalyst H4[SiW 12O40]/SiO2 (H-SiW12/SiO 2), which can catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol selectively and efficiently without the need of a drying agent. The acetalization process can proceed smoothly at a relatively low temperature under solvent-free conditions. The catalyst of H 4[SiW12O40]/SiO2 can be recycled at least ten times without an obvious decrease in its catalytic activity. As far as we know, the TONs of the H-SiW12/SiO2-catalyzed acetalization of cyclohexanone with ethylene glycol, and benzaldehyde with 1,3-propanediol are the highest reported so far.
- Zhao, Shen,Jia, Yueqing,Song, Yu-Fei
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p. 2618 - 2625
(2014/07/22)
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- Bismuth compounds in organic synthesis: Synthesis of dioxanes, dioxepines, and dioxolanes catalyzed by bismuth(III) triflate
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A simple method for the synthesis of 1,3-dioxolanes from carbonyl compounds has been developed using 1,2-bis(trimethylsilyloxy)ethane in the presence of bismuth(III) triflate as a catalyst. The bismuth(III) triflate catalyzed synthesis of a range of dioxanes and dioxepines has also been developed. In these latter cases, the carbonyl compound is treated with a diol, and triethyl orthoformate is used as a water scavenger. All these methods avoid the use of a Dean-Stark trap. Georg Thieme Verlag Stuttgart.
- Podgorski, Daniel M.,Krabbe, Scott W.,Le, Long N.,Sierszulski, Paul R.,Mohan, Ram S.
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experimental part
p. 2771 - 2775
(2010/10/02)
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- A remarkable iodine-catalyzed protection of carbonyl compounds
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We report here a remarkably simple molecular iodine-catalyzed protection method for various carbonyl compounds as ketals in a general reaction. The iodine-catalyzed reaction of mandelic acid and lactic acid with several aldehydes has furnished a highly diastereoselective synthesis of cis and trans dioxolanones.
- Banik, Bimal K.,Chapa, Marin,Marquez, Jocabed,Cardona, Magda
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p. 2341 - 2343
(2007/10/03)
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- A simple, efficient and general procedure for acetalization of carbonyl compounds and deprotection of acetals under the catalysis of indium(III) chloride
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Indium (III) chloride efficiently catalyzes the protection of a variety of aldehydes and ketones to their corresponding 1,3-dioxolanes and dialkyl acetals in refluxing cyclohexane. On the other hand, deprotection of acetals is also achieved in refluxing aqueous methanol under the catalysis of indium(III) chloride.
- Ranu, Brindaban C.,Jana, Ranjan,Samanta, Sampak
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p. 446 - 450
(2007/10/03)
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