Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

Abstract

IntroductionThe importance of solid acid and base catalysts in clean technologies has been recognized for a long time, and many books and reviews have been published since the text by Tanabe [1]. Tanabe et al.[2] revised their book in 1989, reviewing the definition and classification of solid acids and bases, determination of acidic and basic properties, and catalysis for isomerization, acylation, hydration of alkenes, methanol conversion, dehydration, dehydrogenation, esterification, hydrolysis, hydrocraking (hydrogenolysis), and oxidation reactions. The development of solid acid catalysts has been surveyed in several reviews [3][4][5][6][7][8][9][10]. Catalysis by solid bases and the mechanism of base-catalyzed reactions such as isomerization of alkenes and alkynes, aldol addition and aldol condensation, Henry reaction (nitro-aldol reaction), Knoevenagel condensation, Michael addition, the Tishchenko reaction, alkylation reactions, and addition reactions such as addition of amines to epoxides, transfer hydrogenation (Meerwein-Ponndorf-Verley (MPV) reaction), esterification and transesterification, and liquid-phase oxidations including Baeyer-Villiger oxidation and alkene epoxidation have been recently emphasized by Ono and Hattori [11], encompassing many splendid reviews and papers [12][13][14][15][16][17][18][19][20].The first part of this chapter is intended to survey recent literature on new catalytic materials because the development of new types of metal oxides and layered-and carbon-based materials with different morphologies opens up novel acid-base catalysis that enables new type of clean reaction technologies. Mechanistic considerations of acid-and base-catalyzed reactions should result in new clean catalytic processes for Green and Sustainable Chemistry, for example, transformations of biorenewable feedstock into value-added chemicals and fuels [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The latter part of this chapter, therefore, focuses on biomass conversion using solid acid and base catalysts, which covers recent developments on acid-base, one-pot reaction systems for carbon-carbon bond formations, and biomass conversion including synthesis of furfurals from sugars, biodiesel production, and glycerol utilization.

Solid base catalysed 5-HMF oxidation to 2,5-FDCA over Au/hydrotalcites: fact or fiction?

“… 26 A recent report suggests that bimetallic AuPd nanoparticles supported on carbon nanotubes may obviate the requirement for basicity, although reaction is slow and proceeds under high pO 2 . 27 Solid base supports may circumvent the need for liquid base addition, 28 – 30 with Au/Mg–Al hydrotalcites (HT) reported as effective for FDCA production from HMF under an atmospheric oxygen pressure, 31 or using a biphasic solvent system over AuPd/HT albeit it in the presence of additional Na 2 CO 3 . 32 However, despite the topical nature of Au catalysis, the role of basic supports in aqueous phase oxidations, 33 and potential contribution of homogeneous base on observed performance, 24 , 34 , 35 remains hotly debated.…”

Catalytic Conversions of Biomass-Derived Furaldehydes Toward Biofuels

“…Thus, the balance of CO 2 concentration in the atmosphere on the basis of biomass utilization process is scarcely influenced. A lot of efforts have put into the investigations of new biomass transformation processes and derived technologies (e.g., see [3][4][5][6][7][8]). In this chapter, recent advanced catalytic transformations of biomass-based furaldehydes (furfurals) toward biofuels via hydrogenation/hydrogenolysis are introduced.…”

Role of Pyridinic Nitrogen on Base Catalyzed Knoevenagel Condensation over Pristine CNx

“…Although the reaction is catalysed by weak bases under homogenous conditions but past decade has witnessed a rapid emergence of heterogeneous catalysts where the reaction has been carried out with Lewis acid catalyst. [9] Variety of weakly base promoted catalysts, such as alkali-ion-exchanged zeolites, alkali-ion-exchanged sepiolite, oxynitrides, and t-BuOK supported on xonotlite and reconstructed hydrotalcite has given quantitative yields for a variety of Knoevenagel condensations reaction. [10] Nevertheless, the leaching of the basic particles cannot be excluded for the catalyst.…”