[Show abstract][Hide abstract] ABSTRACT: In the title mol-ecule, C(5)H(6)BrN(3), the pyrimidine ring is essentially planar, with an r.m.s. deviation of 0.007 Å. The Br and N atoms substituted to the pyrimidine ring are coplanar with the ring [displacements = 0.032 (1) and 0.009 (5) Å, respectively], while the methyl C atom lies 0.100 (15) Å from this plane with a dihedral angle between the pyrimidine ring and the methyl-amine group of 4.5 (3)°. In the crystal, C-H⋯N, C-H⋯Br and N-H⋯N hydrogen bonds link the mol-ecules into a two-dimensional network in the (011) plane.
[Show abstract][Hide abstract] ABSTRACT: Biodiesel, chemically consists of fatty acid methyl ester (FAME) produced by methanolysis of natural triglycerides, such as animal fats and vegetable oils, is a kind of biomass energy, which is renewable and ecofriendly. In this article, KF/CaO was used as solid base catalyst for transesterification of soya bean oil and methanol, while ultrasound as supplementary means. Compared to mechanical stirring, ultrasound treatment is an effective method to increase the yield of FAME and shorten reaction time. By single-factor method, the optimisation of reaction conditions has been studied. The research showed that the optimum reaction conditions were: w(catalyst)/w(oil): 3%, reaction temperature: 65°C, n(methanol)/n(oil): 12, reaction time: 1 h, sound intensity: 1.01 W cm(-2), frequency: 20 kHz, the yield of FAME could be 97%.
Natural product research 10/2011; 26(13):1249-56. DOI:10.1080/14786419.2011.564581 · 0.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: There are two independent mol-ecules in the asymmetric unit of the title compound, C(13)H(9)Cl(2)NO, in which the dihedral angles between the phenyl and dichloro-phenyl rings have significantly different values [48.5 (3) and 65.1 (3)°]. In the crystal, the mol-ecules are linked via inter-molecular N-H⋯O hydrogen bonds into chains running parallel to the c axis.
[Show abstract][Hide abstract] ABSTRACT: In the title compound, C(17)H(21)ClN(4)O, the benzene ring is oriented at dihedral angles of 1.59 (3) and 1.27 (3)° with respect to the pyrimidine and pyrazole rings, while the dihedral angle between the pyrimidine and pyrazole rings is 0.83 (3)°. An intra-molecular N-H⋯O hydrogen bond results in the formation of a planar (r.m.s. deviation 0.004 Å) six-membered ring.
[Show abstract][Hide abstract] ABSTRACT: In the mol-ecule of the title compound, C(9)H(8)ClNO(4), an intra-molecular C-H⋯O inter-action results in the formation of a near-planar (r.m.s. deviation 0.002 Å) five-membered ring, which is oriented at a dihedral angle of 4.07 (4)° with respect to the adjacent aromatic ring. In the crystal structure, inter-molecular C-H⋯O inter-actions link the mol-ecules into a two-dimensional network.
[Show abstract][Hide abstract] ABSTRACT: In the molecule of the title compound, C9H8BrNO4, the acetate group is close to planar [maximum deviation = 0.042 (3) Å] and is oriented at a dihedral angle of 73.24 (3)° with respect to the aromatic ring. In the crystal structure, intermolecular C—H⋯O interactions link the molecules into a three-dimensional network, forming R
2(10) ring motifs.
[Show abstract][Hide abstract] ABSTRACT: In the mol-ecule of the title compound, C(9)H(8)ClNO(4), the nearly planar acetate moiety [maximum deviation = 0.015 (3) Å for an O atom] is oriented with respect to the plane of the aromatic ring at a dihedral angle of 73.03 (3)°. In the crystal structure, inter-molecular C-H⋯O inter-actions link mol-ecules into a network. π-π contacts between benzene rings [centroid-centroid distance = 4.000 (1) Å] may further stabilize the structure.
[Show abstract][Hide abstract] ABSTRACT: In this work, the degradation of dimethoate solution in ultrasonic airlift loop reactor (UALR) assisted with advanced oxidation processes was studied. The effects of O3 flow rate, ultrasonic intensity, pH value and reaction temperature on the degradation rate were investigated. UALR imposed a synergistic effect combining sonochemical merit with high O3 transfer rate. Under the optimal operation conditions: ultrasonic irradiation time was 4h, O3 flow rate was 0.41 m3h(-1), ultrasonic intensity was 4.64 W cm(-2), pH value was 10.0, reaction temperature was 25 degrees C, and initial concentration of dimethoate was 20 mg L(-1), degradation rate of dimethoate increased to 90.8%. The experimental results indicated that the method of UALR degradation of organic pollutants in the presence of gas could reduce reaction time and improve degradation rate. UALR was an advisable choice for treating organic waste waters and this device could be easily scale up. Thus this process has wide application prospect in industry.
[Show abstract][Hide abstract] ABSTRACT: The kinetic rules of degradation were studied in ultrasonic airlift loop reactor (UALR) in which O3 was introduced as oxidant and the organophosphorus pesticide dimethoate was used as typical contaminant. It was found that the dimethoate degradations under the individual ultrasonic radiation treatment without O3 (US), the oxidation of O3 gas (O3) and the synergetic effect of UALR and O3 (UALR/O3) were all consonant with the apparent first-order reaction by the kinetics investigations. The dimethoate removal rates of US, O3 and UALR/O3 methodologies under the conditions of dimethoate initial concentration of 50 mg/L, initial solution pH of 6.0, dimethoate solution volume of 80 mL, ultrasonic intensity of 0.5 W/cm2, O3 flow of 200 L/h, temperature of 20 degrees C and the treatment time of 4 h were 27%, 15% and 90%, respectively. Under these conditions, the rate constant enhancement factor of dimethoate degradation reached 4.816. Furthermore, a simplified mechanistic kinetic model was derived from the degradation mechanism of the synergetic effect of US, O3 and hydroxyl free radical (*OH) in the UALR/O3 system.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 07/2008; 29(6):1502-7.
[Show abstract][Hide abstract] ABSTRACT: The promoting effect of ultrasonic wave on the hydrodynamics and mass transfer characteristics of the loop airlift reactor was studied. The gas holdup, liquid circulation velocity, mixing time and overall volumetric mass transfer coefficient were examined and compared, with and without ultrasonic wave in the reactor. The experimental results show that ultrasound has almost no notable effect on the gas holdup, but has a tendency to decrease gradually the liquid circulation velocity and increase the overall volumetric mass transfer coefficient; and the effect on the mixing time is relatively complex. At low superficial gas velocity, the low powered ultrasound promotes the radial mixing of fluid; with the ultrasonic power increasing, ultrasonic vibration obstructs the axial mixing of fluid. Moreover, the effect of ultrasonic wave on the mixing time gradually decreases with the increase in the superficial gas velocity. Therefore there exists an optimal ultrasonic power for hydrodynamics and mass transfer. Correlations were also proposed for the hydrodynamics and mass transfer characteristics of the reactor.
The Canadian Journal of Chemical Engineering 04/2008; 83(2):204 - 211. DOI:10.1002/cjce.5450830207 · 1.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the mol-ecule of the title compound, C(6)H(8)N(2), the methyl C and amine N atoms are 0.021 (2) and 0.058 (2) Å from the pyridine ring plane. In the crystal structure, inter-molecular N-H⋯N hydrogen bonds link the mol-ecules.
[Show abstract][Hide abstract] ABSTRACT: A comparative study of O3 alone and O3/H2O2 was made to evaluate their respective effectiveness for removal of persistent organic pollutants (POPs) from water with 4, 4'-dibro minated biphenyl (4, 4'-DBB) as the model pollutant, and UV254 was used as the surrogate parameter for TOC and DOC. It was found that both processes enhanced the removal rate. Especially, it has been made a further enhancement of the removal of 4, 4'-DBB as H2O2 was added under the alkaline-condition. The final removal rate of 4 mg/L 4, 4'-DBB solution reached 78.0% after reacting for 270 min, while the UV254 value varies with the removal rate and reached 76.9%-77.8% ultimately. It means that the total organic carbon has been removed obviously. Two kinds of solution of different concentration with the same amount of oxidant reacting for the same time have been compared with each other and the results showed that the higher the initial concentration was, the smaller the removal rate was, however, the more the absolute amount could be removed. It was also found that 4, 4'-DBB's removal followed pseudo-first order reaction and the promoted factor f for 4, 4'-DBB removal rate constant was about 1.54.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 10/2007; 28(9):1998-2003.