Marcin Smiglak

Bifunctional quaternary ammonium salts based on benzo[1,2,3]thiadiazole-7-carboxylate as plant systemic acquired resistance inducers

Ionic liquids through their modular design are a very interesting platforms for building bifunctional biologically active salts. This paper presents new bifunctional compounds based on the anionic derivative of ASM, which is a systemic acquired resistance (SAR) inducer, with antibacterial or solubility enhancing agents.

Properties modification by eutectic formation in mixtures of ionic liquids

The composition and temperature of three eutectic mixtures were determined at atmospheric pressure in systems resulting from the combination of pairs of ionic liquids where each ionic liquid was constituted by only one type of cation and only one type of anion. In addition, the three pairs investigated had a common ion (either the cation or the anion), thus totalising just three different ions in the resulting mixture. All three eutectic mixtures had a temperature near the ambient one, meaning a decrease of up to ca. 50 K with regard to the melting temperature of the parent ionic liquids. A characterisation of physical properties (density, viscosity, and surface tension) of the eutectic mixtures was carried out, and compared as appropriate with those of the parent compounds.

Mixtures of ionic liquids as more efficient media for cellulose dissolution

The ability to dissolve cellulose, by using mixtures of ionic liquids, has been studied and compared with results obtained for the corresponding single ionic liquids. The ionic liquid mixtures tested were a 3:7mol/mol mixture of 1-ethyl-3-methylimidazolium chloride ([C2mim]Cl) and 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), and the eutectic mixture (i.e., a 5.1:4.9mol/mol ratio) of [C2mim]Cl and 1-butyl-3-methylimidazolium chloride (C4mim]Cl). The amount of dissolved cellulose was investigated at three different temperatures (323, 348, and 373K) for each system. The greatest amount of dissolved cellulose was obtained for the [C2mim]Cl+[C2mim][OAc] mixture, at 373K, and it was 40g per 100g of solvent. Moreover, attempts were made to lower the viscosity of the resulting systems and improve the dissolution capacity by addition of dimethylsulfoxide (DMSO) as co-solvent. Results showed that addition of DMSO at 50mol% allows the dissolution of even greater amounts of cellulose (up to 43g per 100g of solvent). To the best of our knowledge, this is the largest ever reported amount of dissolved cellulose in ionic liquid media. Additionally, physical properties (density, surface tension, and viscosity) of the investigated ionic liquid mixtures were determined and compared with the values of the corresponding parent salts. The dissolved cellulose could be easily reconstituted from its solution in ionic liquid mixtures by addition of water. The regenerated cellulose was characterized by powder X-ray diffraction (pXRD), thermogravimetric analysis (TGA), and optical microscopy. The analyses confirmed the conversion of the crystal structure of cellulose from cellulose I to cellulose II during the dissolution and regeneration process.

New approach to hydrosilylation reaction in ionic liquids as solvent in microreactor system

Continuous flow-through reactors on a micro scale (microreactors) are being investigated as a new approach to chemical synthesis, due to significantly larger surface-to-volume ratios and micro-structured internal volumes, which allow for much more efficient heat exchange. Functionalized siloxanes, as one of the most important classes of organosilicon compounds, are widely applied in industry. Many of their synthetic methods are based on the catalytic process of hydrosilylation. In our studies, we investigated, as a model, the reaction between 1,1,1,3,5,5,5-heptamethyltrisiloxane and 1-octene, using the Karstedt catalyst dissolved in seven different ionic liquids. The reaction was carried out in batch and in the microreactor system. Studies have shown that the use of ionic liquids in general allows for catalyst recycling and reuse in subsequent reaction cycles. Moreover, the use of microreactors intensified the process, allowing a higher yield to be obtained than when using conventional batch reactions.

An Ionic Liquid-Based Next Generation Double Base Propellant Stabilizer

Due to extreme environments in overseas theaters of operation, a number of ordnance devices and munitions have been exposed to high temperatures in excess of their qualified limit. The resultant reduction in the propellant service life has resulted in an effort to identify and develop advanced thermal stabilizers. Simply adding more of the fielded inert stabilizer would negatively affect propellant performance, so one solution under consideration is an energetic stabilizer that does not carry a performance penalty. The approach discussed herein uses ionic liquids because their “designer” nature allows them to be tailored for a specific purpose by choosing specific counterions. Currently an ionic liquid-based stabilizer is being designed which combines a counterion that acts as the stabilizer and a counterion that is energetic. For this application, various state of the art stabilizers that have been altered to give them the proper ionic charge, are being combined with assorted energetic counterion cores to determine the best overall blend of service life and propellant performance. Additionally, two advanced stabilizers are being tested because they appear to provide performance benefits over state of the art stabilizers. This paper summarizes efforts to date in an on-going investigation.

New ionic liquids based on systemic acquired resistance inducers combined with the phytotoxicity reducing cholinium cation

Systemic acquired resistance (SAR) is one of the most promising ways to support plants in the fight against viruses. Using this approach biological or chemical factors interact with plants and stimulate their immune system against infections before infection occurs. This paper presents synthesis, physical properties, phytotoxicity and SAR induction efficacy of 15 ionic liquids, derivatives of SAR inducers paired with the cholinium cation, an essential nutrient for organisms. SAR induction efficacy tests were performed on tobacco Nicotiana tabacum var. Xanthi infected by tobacco mosaic virus (TMV).

Optimization and intensification of hydrosilylation reactions using a microreactor system

Utilization of continuous flow chemistry techniques concentrates often on catalytic reactions difficult to be performed for various reasons under typical batch conditions. As a result of the advantages that continuous flow chemistry techniques offer, in regards to solving the problems related to carrying out the reactions in batch systems, microreactors are becoming more and more popular. Herein we present our results for the optimization and intensification of hydrosilylation reactions with three different alkenes. We performed reactions between 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMTS) and 1-octene, 3-allyloxy-1,2-propanediol or allyl glycidyl ether with the Karstedt catalyst in both batch and microreactor systems, where we have monitored the reaction using in situ IR (controlling conversion of Si–H). Application of a microreactor system for performing the hydrosilylation reaction in a significant way allowed the conversion of Si–H bonds to be increased when using all the examined olefins. Especially lengthening of the microreactor system, while maintaining the reactants’ residence time in the microreactor, caused an increase in the Si–H conversion. With no doubt, performing the synthesis of organofunctional silicon compounds in continuous flow microreactor systems has great potential.

The effect of the catalyst and the type of ionic liquid on the hydrosilylation process under batch and continuous reaction conditions

Organofunctional silanes, siloxanes, and polysiloxanes are widely applied in industry. One of the most popular and commonly used processes for the synthesis of these compounds is based on the catalytic hydrosilylation reaction. However, even though this reaction was widely investigated in homogeneous single-phase systems, there is still a large problem with later separation of the catalyst from the product after completion of the reaction. One of the solutions to this problem is use of ionic liquids to create a biphasic system with substrates, where the catalyst is dissolved in the ionic liquid phase, and this phase can be easily separated and reused. Moreover, optimization and intensification of the process can be improved by using continuous flow-through reactors on a microscale (microreactors) due to significantly larger surface-to-volume ratios and microstructured internal volumes of the reactors, allowing much more efficient heat exchange. In our studies, we have investigated, as a model, the reaction between 1,1,1,3,5,5,5-heptamethyltrisiloxane and 1-octene, using a series of platinum and rhodium catalysts dissolved in four different ionic liquids in batch and in the microreactor system. Studies have shown that the use of ionic liquids in general allows for catalyst recycling and reuse in subsequent reaction cycles. Moreover, the use of microreactors intensified the process, allowing a higher yield to be obtained than under conventional batch reaction conditions.

Ionic liquids—a novel material for planar photonics

Electron beam patterning is an important technology in the fabrication of miniaturized photonic devices. The fabrication process conventionally involves the use of radiation sensitive polymer-based solutions (called resists). We propose to replace typical polymer resists with eco-friendly solvent-free room temperature ionic liquids (RTILs), which are polymerized in situ and solidified by an electron beam. It is demonstrated that the shapes of polymerized structures are different for high-viscous Cl-based RTILs and low-viscous NTf2-based RTILs. Due to the the satisfactory quality of the polymerized spatial microstructures and their light transmission properties, the RTIL-derived microstructures are potentially attractive as photonic elements for near-infrared.

Ionic liquids as bioactive chemical tools for use in agriculture and the preservation of agricultural products

Organic salts called “ionic liquids” have already quite a long history; nevertheless, they still attract major attention from the scientific community and increaselly industry. In this review article, we present the recent progress made in the field of ionic liquids bearing bioactive components, with a particular emphasis on their use as chemical tools in agriculture and the preservation of agricultural products. The article comprehensively describes the use of ionic liquids as bactericides, fungicides, herbicides, wood preservation agents, plants stimulants, growth regulators, and their possible advantages in comparison with conventional, presently used formulations. Ionic liquids unique properties and multifunctionality are underlined in particular, in order to show their high value as bioactive substances. Moreover, the ILs biodegradability, toxicity, and the methods for their determination and prediction are discussed. An outlook on possible future progression in this field finalizes this article.