Advanced Materials Research Vols. 1033-1034

Abstract: A novel method for the determination of rhodium in waste thiourea rhodium samples was established by inductively coupled plasma optical emission spectrometry after samples digested by Teflon pressure digestion vessel with aqua regia. Such experiment conditions were investigated as the influence of sample dissolution methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the limit of detection (LODs) of Rh for tested solution was 9 ng mL^-1. The relative standard deviations (RSDs) for Rh was 1.98 % (C_Rh = 1 mg L^-1, n = 7). The linear range of calibration graph for Rh was 0 ~ 150.00 mg L^-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.

Abstract: A series of bis (2-tetrahydrobenzofuranyl) alkanes in good yield under solvent-free conditions from differently aromatic substituted aldehydes and 3-methyl-6,7-dihydrobenzofuran-4(5H)-one in the presence of H₂SO₄•SiO₂ as catalyst at 90oC. Their structures were characterized by NMR, IR and ESI-MS. The proposed mechanism for the H₂SO₄•SiO₂-catalyzed condensation reaction have been discussed in the work. This versatile approach has the advantages of broad functional group compatibility, short reaction times, simple operation and environmentally benign nature.

Abstract: A novel method for the determination of rhodium in rhodium-loaded carbon catalyst samples was established by inductively coupled plasma atomic emission spectrometry after samples digested by microwave oven with aqua regia. Such experiment conditions were investigated as the influence of sample digestion methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the limits of detection (LODs) of Rh for tested solutions were 9 ng mL^-1. The relative standard deviations (RSDs) for Rh were 2.11 (C_Rh = 1 mg L^-1, n = 7). The linear ranges of calibration graphs for Rh were 0 ~ 150.00 mg L^-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.

Abstract: Ni catalysts supported on CeO₂ and HZSM-5 supports were prepared and tested as catalysts in the liquid hydrogenation of maleic anhydride. Particularly Ni/HZSM-5 was active and selective in the hydrogenation of maleic anhydride to ڃ-butyrolactone. The characterization results of X-ray diffraction (XRD), N₂ adsorption and CO temperature programmed reduction (CO-TPR) evidenced that the higher C=O hydrogenation ability of Ni/HZSM-5 catalyst was related to strong interaction between Ni particles and HZSM-5, and the high dispersion of fine Ni particles on the surface of support. Further, the acidic HZSM-5 support benefits the dehydration performance during the C=O bond hydrogenation process, which favored the production of ڃ-butyrolactone. The dual-functional Ni/HZSM-5 catalyst possesses both hydrogenation and dehydration activity.

Abstract: A new type of polymer-supported catalyst, [PS-(PBIM)₂Cu (II)], was synthesized by loading 2-(2’-pyridyl) benzimidazole on chloromethylated propylene-styrene graft copolymer fiber and subsequent treatment with Cu (OAc)₂ in methanol. The prepared catalyst was used in the oxidation of styrene with tert-butyl hydroperoxide (TBHP) as the oxidant. The important reaction conditions, such as the reaction temperature, the ratio of oxidant/styrene, and the recycle times were examined. The experimental results show that the catalyst reveals relatively high catalytic performance with 84% conversion for styrene. The suitable conditions are as follows: n (styrene):n (TBHP)=1:3, the reaction temperature of 80 °C and the reaction time of 8 h. In addition, the catalyst used repeatedly for 3 times can still possess high catalytic activity.

Abstract: A polyoxometalate-based ionic liquid, 1-(4-sulfonic acid) methylimidazolium phosphotungstate ([MIMBS]₃PW₁₂O₄₀), was synthesized and characterized by Fourier transform infrared spectrum, nuclear magnetic resonance, electrospray ionization mass spectrum and thermogravimetric analyzer. [MIMBS]₃PW₁₂O₄₀ exhibited high activity for the extractive catalytic oxidative desulfurization process, together with H₂O₂ and CH₃CN/H₂O. The sulfur removal of DBT could reach 99.9% under wild conditions, and the catalyst could be used three times with only a slight decline in activity.

Abstract: A hydrophobic Brønsted acidic ionic liquid 1-octyl-3-(butyl-4-sulfonate) imidazolium hydrogen sulfate ([BsImR₈][HSO₄]) was synthesized and characterized by fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), electron spray ionization mass spectrometry (ESI-MS) and thermogravimetry (TG). [BsImR₈][HSO₄] was used as an efficient catalyst for esterification of oleic acid with methanol to biodiesel. It was founded that [BsImR₈][HSO₄] exhibited high catalytic activity, which is near to that of H₂SO₄.It was ascribed to its strong Brønsted acidity. The catalyst could maintain high activity after five cycles of use.

Abstract: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (CS-12) is a non-water-soluble diol ester and an emerging green additive, widely used in paint industry. It can be synthesized by isobutyraldehyde with alkali as catalyst. In this article, several catalysts were studied for the synthesis of CS-12, for example, sodium hydroxide, calcium hydroxide, the mixture of sodium hydroxide and calcium hydroxide, sodium methoxide, the solution of sodium methoxide and methanol, and sodium ethoxide. Sodium hydroxide was finally selected as the optimal catalyst for the reaction. The effect of the amount of catalyst, reaction temperature and reaction time on the reaction were investigated by orthogonal experiments. The final optimal conditions are as follows: the catalyst dosage is 2 %, the reaction temperature is 50 °C, the reaction time is 4h. Under these conditions, the conversion of isobutyraldehyde is 93.10%, the selectivity of target product is 92.98%.

Abstract: Three chalcone derivatives were synthesized by the reaction of acetophenone with dimethylamino benzaldehyde, vanillin, diphenyl formaldehyde, respectively. The results showed that: A yield of 80.4% was obtained by the reaction of acetophenone and dimethylamino benzaldehyde in ethanol as solvent, 10% NaOH solution as catalyst at room temperature. A yield of 25.0% was obtained by the reaction of acetophenone and vanillin in ethanol as solvent, a mixed glacial acetic acid and hydrochloric acid as the catalyst, adding 10% KOH solution for dehydration by heating after the reaction at room temperature. A yield of 76.3% was obtained by the reaction of acetophenone and diphenyl formaldehyde in ethanol as solvent, 10% NaOH solution as catalyst at room temperature. Acid was used as the appropriate catalyst when chalcone derivatives were synthesized by aldehyde with hydroxy.

Abstract: Ultrasound-assisted oxidative desulfurization (UAODS) of diesel fuel in H₂O₂/Heteropoly acid/Solvent systems, was investigated. Effects of solvent, catalyst, ultrasound and reaction temperature on the oxidation desulfurization of diesel fuel were investigated. When MPA/oil was 2%wt, methanol/diesel fuel was 20%wt, ultrasound power was 400 W and ultrasound time was 10 min, the sulfur content of diesel fuel was decreased from 211 ppm to 19 ppm. The use of ultrasonic irradiation in H₂O₂/Heteropoly acid/Solvent system significantly improved the efficiency of the oxidation reaction, and solvent was helpful to make the oxidative reaction happen in the same one phase.