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Commercial chiral stationary phases (CSPs) are based mainly on polysaccharides supported on silica; however, the pharmaceutical industry shows a special interest on chiral separations, exhibiting high financial investment in the development of new CSPs. These can be structured by a new optically active compound or different support. Thus, metal–organic frameworks (MOFs) are crystalline materials that arise with great potential for support, due to its high porosity, the strong intermolecular force between the metal and the ligand selectivity, and high adsorption capacity. Interested in this, this work proposes a new CSP using the metal–organic structure ZIF-8 (Basolite Z1200) due to its high mechanical stability. To this end, it is proposed the modification of the ZIF-8 with the optically active compound, tris-3,5-dimethylphenylcarbamate amylose. Through characterization textural, structural, and physicochemical performed, it is possible to confirm the synthesis of the chiral compound (amylose carbamate), as well as the functionalization of the metal–organic structure with tris-3,5-dimethylphenylcarbamate amylose (ZIF-8-PEI-CA). In addition, as a validation technique, HPLC can detect the presence of enantiomers present in the racemic mixture of Troger bases.

Structural, chemical, morphological, and hydrophilic surface characteristics of SBA-15 silica synthesized by hydrothermal method in an autoclave and in a microwave-heated reactor were analyzed in this work. The influence of time and temperature on these characteristics was investigated. Materials were characterized by textural analysis (BET), FTIR, TGA, XRD, goniometer contact angle, SEM, and TEM. It was possible to obtain SBA-15 silicas assisted by microwave heating irradiation with short-time synthesis (0.5–8 h) compared with the hydrothermal classic method (24 h). Materials presented surface area between 650 and 850 m2 g−1. Through the XRD and TEM results, it was observed that mesostructured materials with two-dimensional, long-range, and hexagonal ordered channels are characteristic of SBA-15. This study showed that heating by microwave irradiation during silica synthesis generates materials with a greater amount of silanol groups. It is possible to control the surface properties of SBA-15 during the microwave-assisted synthesis through temperature tuning. Higher temperature provided SBA-15 with higher hydrophilicity.

The synthesis of adequate adsorbents and efficient methods to separate CO2 present in natural gas streams in petroleum industry has been receiving increased attention in academic and industrial centers. The presence of CO2 in those streams causes serious inconvenient in the transport and processing of natural gas. In this work, the synthesis of pure (SA) and functionalized with (3-aminopropyl) triethoxysilane (APSA) silicas aerogel was performed under microwave irradiation and subsequent drying with supercritical CO2 (SC-CO2). Materials were characterized in relation to their surface area (BET), pore volume (BJH), thermal decomposition (TGA), carbon, hydrogen and nitrogen content (CHN), functional groups (FTIR) and morphology (SEM). The results indicated a modification of the surface of silica with APTES. In addition, the methodology for synthesis and drying of the silica aerogel was efficient and reduced the total time of synthesis. Materials were used as adsorbents in the separation of CO2/CH4 mixtures by using a high-pressure adsorption cell coupled to a near infrared spectroscopy (NIR) probe to monitor CO2 and CH4 concentrations. Adsorption experiments were conducted at 20°C, pressures from 90 to 120 bar and CO2 concentration in the mixture up to 10 mol%. Silica APSA presented adsorptive capacities of 3.30 mmol g−1 at 90 bar and 10.20 mmol g−1 at 120 bar, better than those obtained with the commercial 3-aminopropyl-functionalized silica gel (APSC) of 0.88 mmol g−1 at 90 bar and 9.43 mmol g−1 at 120 bar. NIR was able to quantify the adsorption of CO2 at high-pressure.

Phenolic compounds are toxic pollutants that are harmful to the human body and aquatic environments, with carcinogenic potential and frequently found in industrial effluents at high levels....

The large volumes of natural gas production mean that the processes currently used in the oil industry no longer meet such demand. Therefore, there is an expectation that adsorption processes will reach up to 200 bar in order to process the large volume of natural gas produced. However, it is not known if the materials used in this process would remain stable after being subjected to high pressures. In this way, sorption studies of host molecules such as CO2 at high pressures are important to understand the structural, thermal and chemical changes of this material. Therefore, the objective of this work is to perform stability experiments with MOF-177 using CO2 in an equilibrium cell at a fixed pressure of 200 bar at different temperatures of 20 °C, 40 °C and 60 °C for 12 h. The X-ray diffraction measurements showed that the metal-organic structure underwent irreversible amorphization with increasing temperature. The samples treated at 20 °C and 40 °C did not show significant surface area changes. However, at 60 °C there was an expressive reduction. All samples showed thermal stability up to 400 °C. By means of the FT-IR and SEM analysis, it was possible to observe that there was no chemical and morphological change in the MOF-177 and in the samples submitted to high pressure at different temperatures.

It is recognized that asphaltenes have a tendency toward aggregation and precipitation. Even at low concentrations, they can adsorb at interfaces/surfaces where each type of interaction plays an im...

Industry and academia have shown great interest in the synthesis of organic–inorganic hybrid material because the modification of inorganic supports with organic groups increases the options for us...

The possibility of producing new compounds that combine organic and inorganic materials for improved properties has become increasingly attractive to material science research. The synthesis of organic-inorganic hybrid materials, such as silica modified with an ionic liquid, is an emerging alternative, because the porous silica matrix is already used in several chemical and materials science fields, and ionic liquids have advantageous characteristics compared to other organic compounds. However, the synthesis of hybrid materials involves long reaction times and high temperatures. To overcome this problem, the synthesis of these materials assisted by microwave irradiation has been tested, because is a simple and efficient alternative that reduces reaction time. Some organic synthesis reactions assisted by microwaves have higher reaction rates due to thermal effects, related to specific molecular interactions of microwaves with the material. So, the purpose of this work was to synthesize silica modified with the ionic liquid 1-methylimidazolium chloride using conventional heating and microwave irradiation, as well as to characterize and compare the materials synthesized in both methodologies. After synthesizing the organic-inorganic hybrid material by microwave irradiation, it was observed that it reduced synthesis time and improved its textural properties and chemical composition, when compared to material synthesized with conventional heating.

Naphthenic acids cause corrosion in the equipment used in the petroleum processing. Considering difficulties in the identification of the compounds present in the petroleum sample, it is necessary to study new methodologies to identify or remove the acid compounds from complex matrix. Solid phase extraction (SPE) with ionic phases has been used for this purpose, because it promotes greater selectivity, lower consumption of solvents and small amount of the stationary phase. The proposed study is the recovery of acid compounds using SPE method. An ionic silica based hybrid material containing the pyridinium group was developed and used as stationary phase (SiPy). Linear and monocyclic acids were used as standard mixture in the SPE for calculation of recovery. Further tests were performed with Brazilian petroleum. The SiPy stationary phase showed satisfactory results for the recovery and identification of the acidic compounds presented in the standard mixture as well as in the resin fraction from petroleum.

Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples. The proposed study aimed to recover acid compounds using the solid phase extraction method, employing different types of commercial stationary ion exchange phases (SAX and NH(2)) and new phase alumina functionalized with 1,4-bis(n-propyl)diazoniabicyclo[2.2.2]octane chloride silsesquioxane (Dab-Al(2)O(3)), synthesized in this work. Carboxylic acids were used as standard mixture in the solid phase extraction for further calculation of recovery yield. Then, the real sample (petroleum) was fractionated into saturates, aromatics, resins, and asphaltenes, and the resin fraction of petroleum (B1) was eluted through stationary ion exchange phases. The stationary phase synthesized in this work showed an efficiency of ion exchange comparable to that of the commercial stationary phases.

Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples. The proposed study aimed to recover acid compounds using the solid phase extraction method, employing different types of commercial stationary ion exchange phases (SAX and NH(2)) and new phase alumina functionalized with 1,4-bis(n-propyl)diazoniabicyclo[2.2.2]octane chloride silsesquioxane (Dab-Al(2)O(3)), synthesized in this work. Carboxylic acids were used as standard mixture in the solid phase extraction for further calculation of recovery yield. Then, the real sample (petroleum) was fractionated into saturates, aromatics, resins, and asphaltenes, and the resin fraction of petroleum (B1) was eluted through stationary ion exchange phases. The stationary phase synthesized in this work showed an efficiency of ion exchange comparable to that of the commercial stationary phases.

This work is focused on the evaluation of reaction parameters involved in the enzymatic production of 1-glyceryl benzoate, an intermediate substance to carvedilol and propranolol synthesis, catalyzed by Candida antarctica lipase in different organic solvents. To our knowledge, no related study on this subject is available in the open literature. The main goals of the present investigation were to elucidate the relationship between relevant reaction variables and also to determine the optimum conditions for 1-glyceryl benzoate production. Results showed that the strategy adopted for the experimental design proved to be useful in maximizing the reaction conversion in 2-propanol as solvent with Novozym 435 as catalyst. The optimum conditions were found to be methyl benzoate to glycerol molar ratio of 1:1, stirring rate of 150 rpm, 50 °C, enzyme concentration of 10 wt% at 36 h of reaction, with a resulting conversion to 1-glyceryl benzoate of about 29%. Reaction kinetics of 1-glyceryl benzoate production demonstrated that very satisfactory conversions (∼40%) were achieved after 70 h of reaction.