Fine Reactions Research Articles

From bench to industry, the application of all-inorganic solid base materials in traditional heterogeneous catalysis: a mini review.

Acids and bases generally occur in pairs as concepts, and a large number of catalytic reactions can be considered as interactions between acids and bases. Many chemical reactions are a combination of acid-catalyzed processes and base-catalyzed processes, and thus it is particularly important to study and explain the mechanisms of acid-base synergy or acid-base interactions. However, compared to the in-depth research on acid catalysts, there is a lack of research on solid bases. In addition to the application of basic materials to non-petroleum processes, recent studies have also applied basic materials to the catalytic cracking reaction process of heavy oils, providing new ideas for the processing of heavy oils. The formation of carbanions with the contribution of basicity is a critical stage in many fine chemical reactions, as well as in the hydrocarbon cracking reactions promoted by a base. Thus, herein, we summarize the research progress on the main types of all-inorganic solid base catalysts, including the types of catalysts used in non-petroleum processes and petroleum processes, their preparation, the properties of their basic sites, and their structure-performance correlation in the reactions. Also, we provide an outlook on the future research directions of all-inorganic solid base materials.

Kinetic-free discontinuous to continuous transformation of fine chemical reactions: A general experimental procedure

In the fine chemical and pharmaceutical industries, plants are normally operated on a discontinuous multipurpose logic, according to which the same reactor is used for different products on a campaign basis. Moreover, when dealing with relatively fast and exothermic processes, the reaction is preferably performed in indirectly cooled semibatch reactors, where the conversion rate and the heat release can be better controlled. In these cases, if a constant product quality has to be achieved under safer and more efficient conditions, the shift to a continuous plant operation should be considered: this because of more reproducible operating conditions, an effective minimization of dead times and lower reactor volumes for the same production output. In this work a general and easy to use experimental procedure is presented, allowing for selecting the continuous process parameters at the industrial scale through semibatch laboratory experiments without a kinetic characterization of the system.

Porous carbon: A versatile material for catalysis

Heterogeneous catalysis is an exciting field in constant development. New and improved catalysts that can both be effective and economical are always on demand. Activated carbons may well play an important role in this field, as they are a cheaper alternative while more environmentally benign. In this paper, a brief overview of the effort developed in the application of activated carbon as heterogeneous catalysts in various reactions is presented. Functionalised activated carbon has been used as catalyst for fine chemical reactions. Gas-phase reactions for NO, N2O and CO2 conversions were thoroughly studied using activated carbon as catalyst support. In situ characterization techniques proved to be valuable tools to understand carbon gasification mechanism.

Selectivity problem for fine chemical reactions leading to non volatile products: Process configuration and boundary diagrams

In the fine chemical and pharma industry a number of reaction processes undergo selectivity losses since the target product (typically a low volatility compound) can further react with one of the reactants leading to by-products that must be separated from the target product itself and finally disposed as wastes. In such a situation, even performing the reaction in a standard semi-batch reactor requires a large excess of one reactant to limit the selectivity drop. However, operating the reactor with a large excess of one reactant lowers the reactor productivity. In this work, a process configuration is discussed that, limiting the target product accumulation in the reactor, allows achieving both high process selectivity and high reactor productivity. Moreover, general and easy to use boundary diagrams have been developed, through which the optimal process operating parameters can be easily estimated without solving the mathematical model of the system. Several boundary diagrams are provided for different systems together with a general procedure for their use.

Gold nanoparticle synthesis in microfluidic systems and immobilisation in microreactors designed for the catalysis of fine organic reactions

Our work is focused on two applications of fine tunable microfluidic systems, first to optimize heterogeneous size nanoparticle synthesis and second to build catalytic microreactors for advanced organic reactions. The first part of our work consists in the use of an original microfluidic setup for gold nanoparticle synthesis, which allows a high control of the reaction parameters as the reactants flow, the concentration, the temperature, and the reaction time. We show that using such microfluidic systems permit a better control of the reaction parameters for producing homodispersed 1–2 nm gold nanoparticle. The second part of our work deals with the incorporation of gold nanoparticles into silica capillaries to build catalytic microreactors dedicated to fine chemical reactions. Our strategy consists in the immobilization of gold nanopadiegolirticles onto the inner surface (2D dispersion) or into the inner volume (3D dispersion) of functionalized silica microcapillaries. Characterizations show that by different functionalization procedures, those gold nanoparticles are well anchored inside the microcapillary.