Heteropolyacid supported on ionic liquid decorated hierarchical faujasite zeolite as an efficient catalyst for glycerol acetalization to solketal.

To handle huge amount of glycerol produced in biodiesel industry, glycerol is transformed to value-added products. In this regard, glycerol acetalization to solketal is industrially attractive. As in this process various by-products can be formed, designing highly selective catalysts is of great importance. In this line, we wish to report a novel catalyst that benefits from strong acidity, high specific surface area and thermal stability, which can selectively form solketal in glycerol acetalization. To prepare the catalyst, hierarchical zeolite was prepared via a novel method, in which partially dealuminated NaY was treated with PluronicF-127 and then reacted with NH4NO3 to furnish the H-form zeolite. Hierarchical faujasite was then achieved through calcination and template removal. Subsequently, it was functionalized with ionic liquid and used for the immobilization of heteropolyacid. The results indicated the importance of the mesoprosity of zeolite and the presense of ionic liquid functionality for achiveing high solketal yield. Moreover, among three investigated heteropolyacids, phosphomolybdic acid exhibited the highest catalytic activity. In fact, using 10 wt% catalyst at 55 °C and glycerol to acetone molar ratio of 1:20, solketal with yield of 98% was furnished under solvent-less condition. Besides, the catalyst was recyclable with low leaching of heteropolyacid.

Lipase@zeolitic imidazolate framework ZIF-90: A highly stable and recyclable biocatalyst for the synthesis of fruity banana flavour.

A zeolitic imidazolate framework (ZIF-90) has been synthesized through solvothermal method. The structure was characterized by means of FT-IR spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS). The synthesized ZIF-90 was applied as a support for immobilization of porcine pancreatic lipase (PPL). The immobilized enzyme (PPL@ZIF-90) exhibited immobilization yield and efficiency of 66 ± 1.8% and 89 ± 1.4%, respectively. The pH and thermal stability of PPL was improved after immobilization and the initial activity was retained at about 57% after 20 days of storage at 4 °C for PPL@ZIF-90. Moreover, about 57% of the original activity was remained following 10 cycles of application. In Michaelis-Menten kinetic studies, Km value for PPL@ZIF-90 was lower, while, the Vmax was higher than free PPL. Moreover, optimized conditions to produce fruity banana flavour upon esterification of butyric acid were investigated. The optimum esterification yield was 73.79 ± 1.31% in the presence of 245 mg PPL@ZIF-90, alcohol/acid ratio of 2.78 and 39 h reaction time. PPL@ZIF-90 showed 39% relative esterification yield after six cycles of reuse. The results suggested that PPL@ZIF-90 can be used as a potential effective biocatalyst for synthesis of isoamyl butyrate.

Biodegradation of bisphenol A by the immobilized laccase on some synthesized and modified forms of zeolite Y.

Bisphenol A (BPA) is an environmental pollutant with adverse effects on different ecosystems. In this study, immobilized laccase enzymes onto inorganic supports were used to remove BPA. Laccase was successfully immobilized on sodium zeolite Y (NaY) and its modified desilicated (DSY) and dealuminated (DAY) forms. NaY-based supports were instrumentally characterized. The immobilized laccase on NaY (laccase@NaY), desilicated (laccase@DSY), and dealuminated (laccase@DAY) forms showed significant improvement on immobilization yield (IY%) and efficiency (IE%). Laccase@DSY and laccase@NaY showed IY% = 73.18 ±â€¯3.33 % and 46.23 ±â€¯1.81 % and IE% = 94.50 ±â€¯1.86 %, and 74.39 ±â€¯1.41 %, respectively, whereas IY% and IE% for laccase@DAY were achieved as 81.12 ±â€¯1.32 % and 98.56 ±â€¯2.93 %, respectively. The supports also increased the enzyme characteristics such as pH-temperature range, catalytic stability, and reusability. Km values were 0.73 ±â€¯0.05, 0.26 ±â€¯0.09, 0.31 ±â€¯0.5, and 1.01 ±â€¯0.03 mM for laccase@NaY, laccase@DAY, laccase@DSY, and the free enzyme, respectively. The enzyme demonstrated higher biodegradation ability of bisphenol A upon immobilization on the supports compared to that of the soluble enzyme. A bio-removal yield of 86.7 % was obtained considering three parameters including amount of laccase@DAY (8 U mg-1), concentration of BPA (0.5 mM), and treatment time (1 h) based on response surface methodology (RSM). Biodegradation metabolites (49 ±â€¯5.8 %) and unconverted BPA (14 ±â€¯5.2 %) were analyzed by gas chromatography-mass spectrometry.

A Review on the Catalytic Acetalization of Bio-renewable Glycerol to Fuel Additives.

The last 20 years have seen an unprecedented breakthrough in the biodiesel industry worldwide leads to abundance of glycerol. Therefore, the economic utilization of glycerol to various value-added chemicals is vital for the sustainability of the biodiesel industry. One of the promising processes is acetalization of glycerol to acetals and ketals for applications as fuel additives. These products could be obtained by acid-catalyzed reaction of glycerol with aldehydes and ketones. Application of different supported heterogeneous catalysts such as zeolites, heteropoly acids, metal-based and acid-exchange resins have been evaluated comprehensively in this field. In this review, the glycerol acetalization has been reported, focusing on innovative and potential technologies for sustainable production of solketal. In addition, the impacts of various parameters such as application of different reactants, reaction temperature, water removal, utilization of crude-glycerol on catalytic activity in both batch and continuous processes are discussed. The outcomes of this research will therefore significantly improve the technology required in tomorrow's bio-refineries. This review provides spectacular opportunities for us to use such renewables and will consequently benefit the industry, environment and economy.

Low-Turn-On-Voltage, High-Brightness, and Deep-Red Light-Emitting Electrochemical Cell Based on a New Blend of [Ru(bpy)3]2+ and Zn-Diphenylcarbazone.

Deep red light-emitting electrochemical cells were prepared based on a blend of [Ru(bpy)3]2+, a cationic complex, and a neutral Zn(II)-complex based on diphenylcarbazone ligands, named Zn(DPCO). The crystal structure of the Zn(DPCO)2 (bpy)] molecule revealed that the DPCO ligand has been deprotonated to form DPCO- and coordinated to the Zn center metal through the C=O and N=N moieties of DPCO. From the cyclic voltammetry results and controlled potential coulometry data of the diphenylcarbazide (DPC) ligand, it is possible to establish that DPC is oxidized in an irreversible process at +0.77 V, giving DPCO and later oxidized at a higher potential (+1.32 V) to produce diphenylcarbadiazone (DPCDO). A detailed assignment of UV-vis spectra futures to determine the origin of ground- and excited-state transitions was achieved by time-dependent density functional theory calculations, which showed good agreement with the experimental results. Using a simple device architecture, we obtained deep red electroluminescence (EL) with high brightness (740 cd m-2) and luminous efficiency of 0.39 cd/A at a low turn-on voltage of 2.5 V. The favorable configuration of the cell consists of only a blend of complexes of indium tin oxide as the anode electrode and molten alloy cathode (Ga/In) without any polymer as the transporting layer. The comparison between [Ru(bpy)3]2+ and [Ru(bpy)3]2+/Zn(DPCO) demonstrates a red shift in the EL wavelength from 625 to 700 nm in the presence of Zn(DPCO), revealing the importance of using blends for future systems.

Artificial photosynthesis based on ruthenium(II) tetrazole-dye-sensitized nanocrystalline TiO2 solar cells.

We have demonstrated the optical and morphological properties of a novel TiO2 nanoparticle as photoanode in order to apply in dye sensitized solar cells. The nanoparticles were synthesized through hydrothermal method in Tri-n-octyl amine (TOA) as capping agent. From the results it is concluded that the molar ratio of TiCl4 and TOA has remarkable influence on the size and homogeneity of the nanoparticles. The optimized nanoparticles structure for photoanode incorporated into dye-sensitized solar cell was obtained via the molar ratio of 1:10 for TiCl4:TOA. It has also studied the photovoltaic properties of different synthesized TiO2 nanocrystalline (1-4) anchored to ruthenium(II) complexes. 4-(1H-tetrazole-5-yl) benzoic acid (TzBA) applied as an anchoring ligand and 2,2-bipyridine (bpy), 1,10-phenanthroline (phen) and pyridine tetrazole (pyTz) used as ancillary ligands. A solar energy to electricity conversion efficiency (η) of 1.06% was obtained for [Ru(TzBA)(bpy)(pyTz)(NCS)] (5) under the standard AM 1.5 irradiation with a Jsc of 2.29 mA cm(-2), a Voc of 0.51 V, and FF of 55% which are the highest values among Ru(TzBA) complexes. DSSC study reveals that pyTz as an auxiliary ligand exhibits improved current generating capacity than the bpy and phen, which are introduced by dye (5).

5,6-Dioxo-1,10-phenanthrolin-1-ium nitrate.

In the title salt, C(12)H(7)N(2)O(2) (+)·NO(3) (-), the monoprotonated cation is connected to the nitrate anion by a hydrogen bond. Weak C-H⋯O hydrogen bonds hold the planar cations together in a layer structure.