Probability of Reaction Pathways of Amine With Epoxides in the Reagent Ratio of 1:1 and 1:2

The algorithm for generating and estimating the probability of possible reaction pathways for multichannel bimolecular interactions was used to predict the reaction products in the reagent ratio of 1:1 and 1:2. Here we have considered the possible reaction pathways of the reaction of amine ((1S,2S,4S)-bicyclo[2.2.1]hept-5-en-2-ylmethanamine (1) with epoxides (2-((cyclohexyloxy)methyl)oxirane (2), 2-(phenoxymethyl)oxirane (3), (N-(oxiran-2-ylmethyl)-N-phenylbenzenesulfonamide 8) in order to explain experimental observed data, which indicate differences in the reactivity of glycidyl ethers and glycidylsulfonamide with framework amines. Based on the proposed algorithm [39], we have investigated the reaction in the reagent ratio of 1:1 and 1: 2. Calculated values of activation barriers indicate a low probability of formation of interaction products of amine (1) with epoxide (8) with a (1:2) reagent ratio due to steric hindrances in the reaction center.

Comparative Studies of Mechanochemically Synthesized Insoluble Beta-Cyclodextrin Polymers

: Cyclodextrin (CD) polymers are covalently linked hollow structures that are a network of less flexible macrocycles. They can be divided into two main groups: a) soluble (CDPS); and b) insoluble (CDPIS) polymers. These two types are generally prepared in a similar reaction, and the CD/reagent ratio determines the final properties of the reaction product. Changing this ratio of the generally bifunctionalized crosslinking agent and reaction conditions can lead to CDPS or CDPIS. The classical synthetic way in solution often leads to partial reagent(s) degradation, which frequently results in poorly reproducible products. At the same CD/reagent ratio, the reaction in solution yielded soluble CD polymers, whereas the reaction under mechanochemical conditions produced insoluble CD polymers. Usually, further derivatization of CDPIS or polymerization of derivatized CDs can be difficult or even impossible. The reactivity of hydroxyl groups in methylated CDs is limited so that reactions generally require high-boiling solvents and/or a large excess of reagent. This paper presents an economical, reproducible, and well-scalable synthetic method for producing some insoluble CD polymers. The physicochemical and adsorption properties of CDPIS prepared in a planetary ball mill are also compared.

Catalytic Synthesis of Acetonitrile by Ammonolysis of Acetic Acid

The influence of principal parameters (reagent ratio, reaction temperature, temperature gradients along a catalyst layer) on the yield of the desired product was studied in the reaction of acetonitrile synthesis from acetic acid over γ-alumina. Thus, the increase in ammonia:acetic acid ratio leads to the increase in acetonitrile selectivity and yield. In this work it has been demonstrated that initial temperatures of 360-380 °C are optimum to effectively carry out the process of acetonitrile synthesis. The increase in reaction temperature allows one to increase the yield of acetonitrile, but at elevated temperatures the catalyst carbidization and contamination of the desired product were observed. The additives to the reaction mixture of the substances that decrease the rate of compaction products (CP) formation and participate in the desired product formation are very effective for decreasing the catalyst carbidization. The effect of the composition of a reaction mixture on a catalyst lifetime is considered. The addition of ethyl acetate to acetic acid promotes a greater carbidization as compared to pure acetic acid. The application of a mixture of acetic acid with acetic anhydride at similar acetonitrile yield decreases the catalyst carbidization.

Widening the scope of the corrole sulfonation

The sulfonation reaction has been particularly useful to prepare amphiphilic derivatives of 5,10,15-tris(pentafluorophenyl)corrole, but it has been limited to this corrole. We have studied the scope of this reaction, using 5,10,15-triphenylcorrole as the prototypical example of corrole structure. The reaction protocol has been modified to avoid the corrole aggregation, which limited its reactivity in the neat chlorosulfonic acid. Surprisingly, the reaction shows an unprecedented regioselectivity for corrole derivatives, affording 3 as the main product, but also corrole 5, which is the first example of monosubstituted corrole on pyrrole B. By modulating the corrole:chlorosulfonic acid reagent ratio, it has been possible to obtain the antipodal disubstituted product 6, demonstrating again a not usual regioselectivity for corrole substitution. These results allow the preparation of novel amphiphilic corrole derivatives, which open up their potential applications in different fields.

Control of Gold Nanostructure Morphology by Variation of Temperature and Reagent Ratios in the Turkevich Reaction

In this paper, we demonstrate that the Turkevich reaction can be used to obtain not only spherical gold nanoparticles of various sizes, but also nanoparticles of different morphologies. The effect of the molar ratios of citrate to HAuCl4 at various temperatures has been studied. It was found that the reagent ratio plays a significant role in defining the morphology of the gold nanosystems formed at low temperatures. This study shows that by controlling the reagent ratios and the reaction temperature of the Turkevich reaction, nano-structured gold systems with various shapes, including spheres, wires, networks, and systems comprising polygonal nanoparticles only or nanochains only, with the latter two morphologies reported for the first time, can be obtained. The gold nanosystems obtained in this fashion were characterised by transmission electron microscopy and UV–visible absorption spectroscopy.