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Open AccessArticle

Synthesis of Formate Esters and Formamides Using an Au/TiO2-Catalyzed Aerobic Oxidative Coupling of Paraformaldehyde

Department of Chemistry, University of Crete, Voutes, 71003 Iraklion, Greece
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Nanomaterials 2017, 7(12), 440; https://doi.org/10.3390/nano7120440
Received: 18 September 2017 / Revised: 20 November 2017 / Accepted: 6 December 2017 / Published: 12 December 2017
(This article belongs to the Special Issue Noble Metal Nanoparticles in Catalysis)
A simple method for the synthesis of formate esters and formamides is presented based on the Au/TiO2-catalyzed aerobic oxidative coupling between alcohols or amines and formaldehyde. The suitable form of formaldehyde is paraformaldehyde, as cyclic trimeric 1,3,5-trioxane is inactive. The reaction proceeds via the formation of an intermediate hemiacetal or hemiaminal, respectively, followed by the Au nanoparticle-catalyzed aerobic oxidation of the intermediate. Typically, the oxidative coupling between formaldehyde (2 equiv) and amines occurs quantitatively at room temperature within 4 h, and there is no need to add a base as in analogous coupling reactions. The oxidative coupling between formaldehyde (typically 3 equiv) and alcohols is unprecedented and occurs more slowly, yet in good to excellent yields and selectivity. Minor side-products (2–12%) from the acetalization of formaldehyde by the alcohol are also formed. The catalyst is recyclable and can be reused after a simple filtration in five consecutive runs with a small loss of activity. View Full-Text
Keywords: formates; formamides; paraformaldehyde; aerobic coupling; Au nanoparticles formates; formamides; paraformaldehyde; aerobic coupling; Au nanoparticles
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MDPI and ACS Style

Metaxas, I.; Vasilikogiannaki, E.; Stratakis, M. Synthesis of Formate Esters and Formamides Using an Au/TiO2-Catalyzed Aerobic Oxidative Coupling of Paraformaldehyde. Nanomaterials 2017, 7, 440.

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