Tomar / Mishra / Arya Solid Base Catalysis: A New Frontier in Industrial Sustainability

1. Auflage 2025
ISBN: 979-8-89881-147-1
Verlag: De Gruyter
Format: EPUB
Kopierschutz: 0 - No protection

E-Book, Englisch, 300 Seiten

Solid Base Catalysis: A New Frontier in Industrial Sustainability showcases the efficiency, reusability, and environmental benefits of solid based catalysts in modern green chemistry. Across ten chapters, the book presents advanced catalyst fabrication techniques, including sol-gel, hydrothermal, vapor deposition, and innovative waste-derived approaches paired with cutting-edge structural and spectroscopic characterization tools. The text highlights catalyst-enabled organic synthesis, biomass conversion, pharmaceutical intermediate production, heterocycle generation, and renewable energy applications, bridging foundational principles with industrial relevance. Detailed case studies on hydrogenation, multicomponent reactions, transesterification, depolymerization, bond-forming reactions, and CO2 conversion to methanol connect academic research with industrial practice, positioning solid base catalysts as a cornerstone technology for sustainable chemistry, circular bioeconomy, and clean-energy innovation. Key Features Examines cutting-edge synthesis methods for solid base catalysts Analyzes material structure and functionality via advanced characterization techniques Demonstrates catalytic pathways for organic synthesis and fine chemicals manufacturing Enables biomass valorization and renewable feedstock conversion Facilitates hydrogenation, multicomponent, and C-C/C-N/C-S bond-forming reactions Advances CO2 utilization, bio-oil upgrading, and sustainable fuel production Bridges fundamental catalysis principles with industrial case studies and real-world applications

Autoren/Hrsg.

Tomar, Ravi

Mishra, Vivek

Arya, Kapil

Pandey, Garima

Fachgebiete

• Naturwissenschaften Chemie Physikalische Chemie Nuklearchemie, Photochemie, Strahlenchemie

Leseproben

Recent Methods for the Synthesis and Character- ization of Solid-base Catalysts

Ruchi S. Pathak1, Abha R. Vyas1, Radhika N. Kachhadiya1, *

1 Department of Pharmaceutical Chemistry, L. J. Institute of Pharmacy, L. J. University, Ahmedabad – 382210, Gujarat, India

Abstract

Solid-base catalysts have acquired significant attention due to their essential role in various chemical processes, including catalytic transformations, environmental remediation, and energy conversion. This chapter highlights a comprehensive overview of current approaches to the synthesis, characterization, innovative methods, and techniques employed in the development of solid-base catalysts. A wide array of methodologies has emerged, ranging from traditional techniques to cutting-edge approaches, facilitating the design and optimization of solid-base catalysts. The synthesis section discusses novel approaches such as sol-gel hydrothermal, nanoparticle immobilization, impregnation, metal-organic framework, fly ash technique, template-assisted techniques, and conventional methods like generation of the basic site by pretreatment at high temperature. Each technique offers unique advantages in controlling catalyst morphology, composition, and surface properties. Furthermore, recent developments in characterization techniques like X-ray diffraction, Fourier-transform infrared spectroscopic, NMR, Temperature programmed desorption, microscopic and surface analysis methods such as indicator method, etc., have enabled detailed insights into the physicochemical properties and active sites of catalysts and structure-activity relationships governing the catalytic performance of solid-base materials. Moreover, computational methods play an essential role in predicting and optimizing the catalytic performance of these materials. By summarizing these recent methodologies, this chapter aims to provide valuable insights into the advancements in solid-base catalyst development, paving the way for enhanced catalytic efficiency and sustainability in various chemical processes.

Keywords: Morphological analysis, Solid-base catalysts, Spectroscopic techniques, Structural analysis, Synthetic methods.

* Corresponding Author Radhika N. Kachhadiya: Department of Pharmaceutical Chemistry, L. J. Institute of Pharmacy, L. J. University, Ahmedabad – 382210, Gujarat, India; E-mail: [e-mail]

INTRODUCTION

Solid base catalysts are materials that can donate electrons or are capable of abstracting protons from reactant molecules based on their types, like Bronsted-

Lowry Bases, Arrhenius bases, and Lewis bases. Metal oxides, Hydroxides, Carbonates, and supported alkali/alkaline earth metals are examples of Solid base catalysts used for many base-catalyzed reactions [1-4]. Solid base catalysts can be synthesized through conventional methods like basic site generation by pretreatment at high temperatures, precipitation methods, nanoparticle immobilization, and impregnation. Recently, several advanced methods like metal-organic frameworks [5,6], sol-gel, hydrothermal method, one-pot synthesis, [7, 8], and Fly ash have been widely used for the synthesis of solid base catalysts [8-14].

It is crucial to determine the main characteristics of surfaces to predict their potential as base catalysts. This can be easily achieved by having control over crucial parameters which optimize the catalytic process. The number of basic sites, its origin, and its strength are the main factors that define the basicity of any solid base catalyst. Over the past decade, significant advancement has been made in the methods pertaining to the characterization of solid base catalysts. The structural analysis of the base catalyst uses the Brunauer Emmett-Teller technique and X-ray diffraction analysis. Thermal analysis is conducted using Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Differential Thermal Analysis (DTA), Temperature-Programmed Reduction (TPR), and Temperature-Programmed Desorption (TPD) techniques. Spectroscopy techniques include FT-IR and NMR spectroscopy.

This chapter illustrates the impact of new supports, on the one hand, recent catalyst synthesis methods and characterization techniques of solid base catalysts are also discussed.

Synthetic Methods of Solid Base Catalysts

Generation of the Basic Site by Pretreatment at High Temperature

Usually, the surfaces of basic materials are layered with water and CO2 in the air. Because of that reason, they do not exhibit their catalytic activities. The basic site on the surface of various materials can be generated by high-temperature pretreatment. The high-temperature pretreatment removes surface species like water, CO2, and O2 and allows the materials to exhibit basic properties and promote base-catalyzed reactions. The temperature required for the removal of adsorbed material is the decomposition temperature of hydroxide, carbonate, and peroxide.

The nature of the generated basic site depends on the severity of pretreatment. The molecules that are covering the surface are desorbed when the pre-treatment temperature increases, which is depicted in Fig. (1). For example, MgO pretreated at a temperature below 723 K has relatively very little activity for migration of double bond of 1- butene, but when the temperature rises above 723 K, it shows great activity that is up to a maximum of 873 K [15].

Fig. (1))
Effect of pretreatment temperature on basic site.

Coluccia and Tench presented a model to study the impact of pretreatment temperature on metal oxide surface, specifically MgO, which is shown in Fig. (2). On the surface, there are different coordination numbers of MgO ion couples after high-temperature application to remove adsorbed molecules. Low coordination number sites are located close to edges, corners, and surfaces with a high Miller index. An incease in the pretreatment temperature generates different basic sites corresponding to ion pairs with varying coordination numbers. The most reactive site is the three-fold Mg2+-three-fold O2- ion pair, which is very unstable and has a tendency to reorganize or vanish at high temperatures. Despite its great adsorption of carbon dioxide and water, this pair is also very reactive.

Precipitation

The precipitation method for solid base catalysts involves the formation of solid catalysts by inducing the precipitation of metal ions or compounds from a solution. This process starts with creating a uniform mixture, followed by changes in temperature and the addition of acidic or alkaline solutions. Through chemical reactions, soluble ions in the solution interact with another reagent to produce insoluble solid compounds. Factors like temperature, pH, composition of raw materials, and the solvent used impact the formation of the solid precipitate. The process unfolds in four stages: Precursor mixing and supersaturation, nucleation, crystal formation, and aggregation [16, 17].

Fig. (2))
MgO surface model presented by Coluccia and Tench [1].

ßis a pre-exponential term, s the solid /fluid interfacial energy, ? is solid molecular volume, T is temperature, and s the supersaturation.

Reaction can be simplified as:

A represents the interfacial energy parameter.

Although nucleation and crystal development often occur together, they can be analyzed independently. The separation of these processes is crucial for producing mono-dispersed crystals. Nucleation is particularly challenging in multicomponent systems because it begins with the formation of clusters that can develop spontaneously by adding monomers until they reach a critical size. Smaller clusters will likely break apart, but bigger clusters will keep growing. Nucleation is similar to a chemical reaction, requiring the overcoming of an energy barrier. Therefore, it is essential to achieve a certain level of supersaturation to trigger spontaneous crystallization [17].

The primary focus of this approach is to ensure a consistent pH value throughout the precipitation process. Precipitates such as hydroxides and carbonates are commonly utilized due to their low toxicity, minimal solubility, and simple breakdown.

Co-precipitation

Co-precipitation is a standard technique for synthesizing catalyst precursors, enabling the uniform distribution of multiple metal cations in a solution. This method facilitates the formation of multiple catalyst precursors through rapid solidification, producing highly dispersed, well-mixed, and homogeneous catalysts...