Aggregation properties of sucrose fatty acid esters and some other sugar-based surfactants at different temperatures

Influence of Surfactant for Stabilization and Pipeline Transportation of Iron Ore Water Slurry: A Review

Iron ore is generally transported using a traditional method that releases significant amounts of dust into the environment. In contrast, the pipeline transportation of slurry is noticeably a sustainable approach for efficiently transporting iron ore by reducing the environmental pollution. The interparticle interaction of the iron ore particles should be mutually repulsive for steady dispersion. Surfactants and polymers adsorb efficiently at the solid/liquid interface due to their amphiphilic character, rendering the surface hydrophilic or hydrophobic to create a stable dispersion. The present review discusses the interaction of surfactants on the stabilization of solid particles for the ease of pipeline transportation using various types of stabilization mechanisms. In addition to the effect of surfactant alone, its combination with some other parameters such as particle size distribution, temperature, solid concentration, etc. has been discussed. The review also describes the detailed classification of iron ore, surfactant, and characteristic properties of surfactants.

Effect of Spontaneous and Water-Based Passivation on Components and Parameters of Ti6Al4V (ELI Grade) Surface Tension and Its Wettability by an Aqueous Solution of Sucrose Ester Surfactants

Solid wettability is especially important for biomaterials and implants in the context of microbial adhesion to their surfaces. This adhesion can be inhibited by changes in biomaterial surface roughness and/or its hydrophilic–hydrophobic balance. The surface hydrophilic–hydrophobic balance can be changed by the specifics of the surface treatment (proper conditions of surface preparation) or adsorption of different substances. From the practical point of view, in systems that include biomaterials and implants, the adsorption of compounds characterized by bacteriostatic or bactericidal properties is especially desirable. Substances that are able to change the surface properties of a given solid as a result of their adsorption and possess at least bacteriostatic properties include sucrose ester surfactants. Thus, in our studies the analysis of a specific surface treatment effect (proper passivation conditions) on a biomaterial alloy’s (Ti6Al4V ELI, Grade 23) properties was performed based on measurements of the contact angles of water, formamide and diiodomethane. In addition, the changes in the studied solid surface’s properties resulting from the sucrose monodecanoate (SMD) and sucrose monolaurate (SML) molecules’ adsorption at the solid–water interface were also analyzed. For the analysis, the values of the contact angles of aqueous solutions of SMD and SML were measured at 293 K, and the surface tensions of the aqueous solutions of studied surfactants measured earlier were tested. From the above-mentioned tests, it was found that water environment significantly influences the components and parameters of Ti6Al4V ELI’s surface tension. It also occurred that the addition of both SMD and SML to water (separately) caused a drop in the water contact angle on Ti6Al4V ELI’s surface. However, the sucrose monolaurate surfactant is characterized by a slightly better tendency towards adsorption at the solid–water interface in the studied system compared to sucrose monodecanoate. Additionally, based on the components and parameters of Ti6Al4V ELI’s surface tension calculated from the proper values of components and parameters of model liquids, it was possible to predict the wettability of Ti6Al4V ELI using the aqueous solutions of SMD and SML at various concentrations in the solution.

A Review on Recent Progress of Glycan-Based Surfactant Micelles as Nanoreactor Systems for Chemical Synthesis Applications

The nanoreactor concept and its application as a modality to carry out chemical reactions in confined and compartmentalized structures continues to receive increasing attention. Micelle-based nanoreactors derived from various classes of surfactant demonstrate outstanding potential for chemical synthesis. Polysaccharide (glycan-based) surfactants are an emerging class of biodegradable, non-toxic, and sustainable alternatives over conventional surfactant systems. The unique structure of glycan-based surfactants and their micellar structures provide a nanoenvironment that differs from that of the bulk solution, and supported by chemical reactions with uniquely different reaction rates and mechanisms. In this review, the aggregation of glycan-based surfactants to afford micelles and their utility for the synthesis of selected classes of reactions by the nanoreactor technique is discussed. Glycan-based surfactants are ecofriendly and promising surfactants over conventional synthetic analogues. This contribution aims to highlight recent developments in the field of glycan-based surfactants that are relevant to nanoreactors, along with future opportunities for research. In turn, coverage of research for glycan-based surfactants in nanoreactor assemblies with tailored volume and functionality is anticipated to motivate advanced research for the synthesis of diverse chemical species.

Chemoenzymatic Synthesis of New Aromatic Esters of Mono- and Oligosaccharides

An efficient and convenient chemoenzymatic route for the synthesis of novel phenolic mono-, di- and oligosaccharide esters is described. Acetal derivatives of glucose, sucrose, lactose and inulin were obtained by chemical synthesis. The fully characterized pure sugar acetals were subjected to enzymatic esterification with 3-(4-hydroxyphenyl) propionic acid (HPPA) in the presence of Novozyme 435 lipase as a biocatalyst. The aromatic esters of alkyl glycosides and glucose acetal were obtained with good esterification yields, characterized by mass spectrometry (MALDI-TOF MS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR). The synthesis of aromatic esters of disaccharide acetals was successful only for the enzymatic esterification of sucrose acetal. The new chemoenzymatic route allowed the synthesis of novel aromatic esters of inulin as the inulin monoacetal monoester and diester and the inulin diacetal monoester with a polymerization degree of two, as well as the inulin monoacetal monoester with a degree of polymerization of three, were obtained by enzymatic acylation of inulin acetals with HPPA. These compounds could represent a new class of sugar ester surfactants with enhanced bioactivity, antioxidative and antimicrobial properties and with potential application in drug delivery systems.