Surface crystallization of ionic liquid crystals

The evidence for surface crystallization in ionic liquids is scarce. The existing reports seem to be contradictory as for its driving forces, since in the two compounds investigated in the literature, the contribution of coloumbic and van der Waals forces is very different. In this work 1-dodecyl-3- methylimidazolium tetrafluoroborate was studied and its surface crystallization characterized by surface tension, ellipsometry and optical microscopy. The results obtained seem to reconcile previous observations, and it was further shown, using the same techniques, that this phenomenon is prevalent in other ionic liquids. MD simulation results illustrate the different possibilities of organization, providing reasonable models to rationalize the experimental observations.This work was developed with the scope of the project CICECO – Aveiro Institute of Materials, UID/CTM/50011/2019, Associate Laboratory LSRE-LCM, UID/EQU/50020/2019, and of Instituto de Telecomunicaço˜es/IT (UID/EEA/50008/2013) – funded by national funds through FCT/MCTES (PIDDAC). M. A. R. M. acknowledges financial support from NORTE-01-0145-FEDER- 000006 – funded by NORTE2020 through PT2020 and ERDF, and P. J. C. acknowledges the FCT for the contract IF/00758/2015. A. R. Bastos from UA is acknowledged for help in the ellipsometry measurements. M. C. C. aknowledges FAPESP (2012/05027-1) and CNPq (310272/2017) for financial support.info:eu-repo/semantics/publishedVersio

Bioepoxidation of isosafrol catalyzed by radish and turnip peroxidases

Peroxidases (PODs) from radish (Raphanus sativus L.) and turnip (Brassica napus L.) were extracted and precipitated with ammonium sulfate using a simple, low cost and quick method. The activities of all steps performed by the vegetable PODs were measured via guaiacol assay. The epoxidation of isosafrol, catalyzed by radish (R. sativus L.) and turnip (B. napus L.) peroxidases was conducted in 20% (v/v) aqueous ethanol solution using 30% (v/v) H2O2 as the terminal oxidant. High conversion (88%) and selectivity (>98%) were obtained after 48 h. The products of the reaction were analyzed by high resolution gas chromatography (GC) and mass spectrometry. Key words: Raphanus sativus L, Brassica napus L., peroxidase, epoxidation, isosafrol. Abbreviation: HRP, Horseradish peroxidase; GC, gas chromatography; POD, peroxidase

Synergistic corrosion inhibition of mild steel in aqueous chloride solutions by an imidazolinium carboxylate salt

Mild steel infrastructure is constantly under corrosive attack in most environmental and industrial conditions. There is an ongoing search for environmentally friendly, highly effective inhibitor compounds that can provide a protective action in situations ranging from the marine environment to oil and gas pipelines. In this work an organic salt comprising a protic imidazolinium cation and a 4-hydroxycinnamate anion has been shown to produce a synergistic corrosion inhibition effect for mild steel in 0.01 M NaCl aqueous solutions under acidic, neutral, and basic conditions; an important and unusual phenomenon for one compound to support inhibition across a range of pH conditions. Significantly, the individual components of this compound do not inhibit as effectively at equivalent concentrations, particularly at pH 2. Immersion studies show the efficacy of these inhibitors in stifling corrosion as observed from optical, SEM, and profilometry experiments. The mechanism of inhibition appears to be dominated by anodic behavior where dissolution of the steel, and in particular the pitting process, is stifled. FTIR spectroscopy provides confirmation of a protective interfacial layer, with the observation of interactions between the steel surface and 4-hydroxycinnamate