A new argument in favor of the ether elimination mechanism: formation of acetals on action of molybdenum alkoxides on carbonyl compounds

Kessler, Vadim G.; Nikitin, Kirill; Belokon, A. I.

doi:10.1016/s0277-5387(98)80006-5

Cited by 28 publications

(19 citation statements)

References 8 publications

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“…A part of this research area therefore coincides with the benzyl alcohol route of metal oxide nanoparticles synthesis [56]. However, more recently, carbonyl compounds such as acetone, acetaldehyde or acetophenone were shown to participate in the reaction and promote the formation of metal oxides [164]. Acetals are formed as organic products of the condensation (Scheme 8).…”

Section: Ether Eliminationmentioning

confidence: 95%

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described.

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Section: Ether Eliminationmentioning

confidence: 95%

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

et al. 2017

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“…Finally, this reaction results in the quantitative formation of the colloidal oxidic compound. [197] The condensation of metal alkoxides on action of carbonyl compounds can, however, also proceed by other pathways, as discussed below (under the section Other Mechanisms) and reported in the literature. [198] www.chemeurj.org Ester elimination: The ester elimination process involves the reaction between metal carboxylates and metal alkoxides [Eq.…”

Section: Nonaqueous Sol-gel Chemistry For Metal Oxide Synthesismentioning

confidence: 99%

“…[196,197] The molybdenum alkoxides MoOA C H T U N G T R E N N U N G (OCH 3 ) 4 and MoOA C H T U N G T R E N N U N G (OCH 2 CH 3 ) 4 transform carbonyl compounds like acetaldehyde and acetone into acetals and ketals, respectively [Eq. (11)].…”

Section: Nonaqueous Sol-gel Chemistry For Metal Oxide Synthesismentioning

confidence: 99%

Organic Reaction Pathways in the Nonaqueous Synthesis of Metal Oxide Nanoparticles

Niederberger

Garnweitner

2006

Chemistry A European J

460

457

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Nonaqueous-solution routes to metal oxide nanoparticles are a valuable alternative to the known aqueous sol-gel processes, offering advantages such as high crystallinity at low temperatures, robust synthesis parameters and ability to control the crystal growth without the use of surfactants. In the first part of the review we give a detailed overview of the various solution routes to metal oxides in organic solvents, with a strong focus on surfactant-free processes. In most of these synthesis approaches, the organic solvent plays the role of the reactant that provides the oxygen for the metal oxide, controls the crystal growth, influences particle shape, and, in some cases, also determines the assembly behavior. We have a closer look at the following reaction systems in this order: 1) metal halides in alcohols, 2) metal alkoxides, acetates, and acetylacetonates in alcohols, 3) metal alkoxides in ketones, and 4) metal acetylacetonates in benzylamine. All these systems offer some peculiarities with respect to each other, providing many possibilities to control and tailor the particle size and shape, as well as the surface and assembly properties. In the second part we present general mechanistic principles for aqueous and nonaqueous sol-gel processes, followed by the discussion of reaction pathways relevant for nanoparticle formation in organic solvents. Depending on the system several mechanisms have been postulated: 1) alkyl halide elimination, 2) elimination of organic ethers, 3) ester elimination, 4) C--C bond formation between benzylic alcohols and alkoxides, 5) ketimine and aldol-like condensation reactions, 6) oxidation of metal nanoparticles, and 7) thermal decomposition methods.

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“…Kessler et al. found that the molybdenum alkoxides MoO(OCH 3 ) 4 and MoO(OCH 2 CH 3 ) 4 reacted rapidly with aldehydes and ketones, transforming the former into colloidal oxidic compounds and the latter into acetals and ketals, respectively . Pazik et al.…”

Section: Chemical Formation Mechanismsmentioning

confidence: 99%

“…Reactionsbetween metala lkoxides and alcohols www.chemeurj.org compounds and the latter into acetalsa nd ketals, respectively. [153] Pazik et al reported the nonhydrolytics ol-gel synthesis of crystalline BaTiO 3 nanoparticles by meanso fa ne ther elimination reaction. [154] Inoue and co-workers synthesized microcrystalline tetragonal zirconia by thermalt reatment of zirconium n-propoxide in glycol at 300 8C.…”

Section: Reactions Betweenmetal Halides and Alcohols Or Ethersmentioning

confidence: 99%

Mechanistic Aspects in the Formation, Growth and Surface Functionalization of Metal Oxide Nanoparticles in Organic Solvents

Deshmukh

Niederberger

2017

Chemistry A European J

101

112

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The synthesis of metal oxide nanoparticles in organic solvents, so-called nonaqueous (or nonhydrolytic) processes represent powerful alternatives to aqueous approaches and have become an independent research field. 10 Years ago, when we published our first review on organic reaction pathways in nonaqueous sol-gel approaches, the number of examples was relatively limited. Nowadays, it is almost impossible to provide an exhaustive overview. Here we review the development of the last few years, without neglecting pioneering examples, which help to follow the historical development. The importance of a profound understanding of mechanistic aspects of nanoparticle crystallization and formation mechanisms can't be overestimated, when it comes to the design of rational synthesis concepts under minimization of trial-and-error experiments. The main reason for the progress in mechanistic understanding lies in the availability of characterization tools that make it possible to monitor chemical reactions from the dissolution of the precursor to the nucleation and growth of the nanoparticles, by ex situ methods involving sampling after different reaction times, but more and more also by in situ studies. After a short introduction to experimental aspects of nonaqueous sol-gel routes to metal oxide nanoparticles, we provide an overview of the main and basic organic reaction pathways in these approaches. Afterwards, we summarize the main characterization methods to study formation mechanisms, and then we discuss in great depth the chemical formation mechanisms of many different types of metal oxide nanoparticles. The review concludes with a paragraph on selected crystallization mechanisms reported for nonaqueous systems and a few illustrative examples of nonaqueous sol-gel concepts applied to surface chemistry.

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A new argument in favor of the ether elimination mechanism: formation of acetals on action of molybdenum alkoxides on carbonyl compounds

Cited by 28 publications

References 8 publications

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

The Power of Non-Hydrolytic Sol-Gel Chemistry: A Review

Organic Reaction Pathways in the Nonaqueous Synthesis of Metal Oxide Nanoparticles

Mechanistic Aspects in the Formation, Growth and Surface Functionalization of Metal Oxide Nanoparticles in Organic Solvents

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