|
Preparation of ibuprofen/lipid composite microparticles
by supercritical fluid technique
WANG Xia, CHEN Hui, GUO Yanni, SU Yuzhong, WANG Hongtao, LI Jun
Frontiers of Chemical Engineering in China. 2008, 2 (4): 361-367.
https://doi.org/10.1007/s11705-008-0066-4
Using the CO2- and N2-assisted atomization processes, the production of ibuprofen/lipid composite microparticles is investigated, in which the lipid includes myristic acid and tripalmitin. The produced composite particles show similar morphology to that of the pure lipids obtained by the same process. In the case of the N2-assisted process, the average size of composite particles is slightly larger than that of the pure lipid particles due to the difficulty of solidification when using N2. In the case of the CO2-assisted process, the average size of composite particles is slightly smaller than that of the pure myristic acid particles, but slightly larger than that of the pure tripalmitin particles. The dissolution study reveals that the drug release from the ibuprofen/myristic acid particles is enhanced in comparison with that of the unprocessed ibuprofen. For the particles produced by the N2-assisted process, the X-ray diffraction (XRD) patterns clearly indicate the encapsulation of ibuprofen into myristic acid. The obtained ibuprofen/tripalmitin composite particles with 5% or 20% of ibuprofen (in mass) evidently show the controlled drug release: only about 20% of the drug is released in 500 min from the ibuprofen/tripalmitin composite particles consisting of 20% ibuprofen prepared by the CO2-assisted process, and the same release is obtained from the ibuprofen/tripalmitin composite particles containing 5% ibuprofen prepared by the N2-assisted process.
参考文献 |
相关文章 |
多维度评价
|
|
Effect of fine solid particles on absorption
rate of gaseous CO
LU Sumin, MA Youguang, SHEN Shuhua, ZHU Chunying
Frontiers of Chemical Engineering in China. 2008, 2 (4): 368-372.
https://doi.org/10.1007/s11705-008-0067-3
The influence of the properties of solid particles in slurry on the absorption of CO2 in the slurry was investigated in a stirred thermostatic reactor. The absorption experiments were carried out in three different slurries consisting of water, cyclohexane and soybean oil, respectively, and three kinds of solid particles (active carbon, active alumina and silica gel) were incorporated into each of the above mentioned slurries separately. The experimental results show that the active carbon particles could enhance the absorption rate of gaseous CO2 in the aqueous slurry, while in the cyclohexane slurry, active carbon particles indicated no the absorption enhancement effect. However, it was observed that the active alumina and silica gel particles could enhance the absorption rate of CO2 in the cyclohexane slurry. These phenomena indicate that the solid particles, which could enhance the gaseous CO2 absorption rate, should possess two properties simultaneously, i.e. they rejected the solvent and had higher adsorption capacity for the solute. The experimental results also show that, as for those solid particles which could enhance the gas absorption rate, the enhancement increased quickly with the increase of solid concentration in slurry at first, and then reached a constant value gradually. It was also found that the enhancement factor was related to the coverage fraction of solid particles on the gas-liquid interface, and due to the reduction of surface fraction with increasing stirred speed, the enhancement factor decreased.
参考文献 |
相关文章 |
多维度评价
|
|
Kinetics of UV curable alkyl 3-mercaptopropionate-vinyl
silizane
SONG Jiale, CHEN Lixin, WANG Yazhou, CHEN Weiwei, WANG Rumin
Frontiers of Chemical Engineering in China. 2008, 2 (4): 390-395.
https://doi.org/10.1007/s11705-008-0080-6
Photopolymerization of vinyl-containing liquid silizane preceramic monomers copolymerized with thiol monomers, based on a step-growth radical polymerization mechanism, is a novel, rapid, inexpensive and simple technique for producing preceramic structures from liquid precursors. The kinetics of alkyl 3-mercptopropionate-vinyl silizane under UV irradiation is investigated by using real-time Fourier transform infrared (FT-IR) and photo-differential scanning calorimetry (photo-DSC). The experimental results show preliminarily that: (1) about 80% conversion of vinyl group has been achieved in the presence of a low concentration photoinitiator under UV irradiation; (2) by increasing the functionalities of the thiol group, the peak rate of copolymerization increases and the final conversion of the vinyl group decreases; (3) the copolymerization is primarily a bimolecular radical termination process; (4) the copolymerization is first-order, i.e., its rate is proportional to the vinyl group concentration and independent of the concentration of thiol group.
参考文献 |
相关文章 |
多维度评价
|
|
Phenolic rigid organic filler/isotactic polypropylene
composites. II. Tensile properties
QI Dongming, SHAO Jianzhong, WU Minghua, NITTA Kohhei
Frontiers of Chemical Engineering in China. 2008, 2 (4): 396-401.
https://doi.org/10.1007/s11705-008-0077-1
A novel phenolic rigid organic filler (KT) was used to modify isotactic polypropylene (iPP). The influence of KT particles on the tensile properties of PP/KT microcomposites was studied by uniaxial tensile test and the morphological structures of the stretched specimens were observed by scanning electron microscopy (SEM) and polarized optical microscopy (POM). We found that the Young’s modulus of PP/KT specimens increased with filler content, while the yield and break of the specimens are related to the filler particles size. The yield stress, the breaking stress and the ultimate elongation of PP/KT specimens were close to those of unfilled iPP specimens when the maximal filler particles size is less than a critical value, which is 7 ?m at a crosshead speed of 10 mm/min and 3 ?m at 200 mm/min, close to that of glass bead but far more than those of other rigid inorganic filler particles. The interfacial interaction was further estimated from yield stress, indicating that KT particles have a moderate interfacial interaction with iPP matrix. Thus, the incorporation of small KT particles can reinforce iPP matrix and simultaneously cause few detrimental effects on the other excellent tensile properties of iPP matrix, due to their organic nature, higher specific area, solid true-spherical shape and the homogenous dispersion of the ROF particles in microcomposites.
参考文献 |
相关文章 |
多维度评价
|
|
Synthesis and properties of polybenzazoles containing
flexible methylene in backbone
XU Xiaohui, LIU Xiaoyun, ZHOU Chengjun, ZHUANG Qixin, HAN Zhewen
Frontiers of Chemical Engineering in China. 2008, 2 (4): 412-416.
https://doi.org/10.1007/s11705-008-0073-5
A novel series of polybenzazoles with rigid-rod benzoxazole cycle and soft methylene segment was designed and synthesized via solution condensation polymerizations from 4,6-diamino-1,3-benzenediol diphosphate, terephthalic acid and aliphatic dicarboxylic acid. The structures of polybenzazoles were characterized by means of FT-IR, 1H NMR and Wide-angle X-ray diffraction (WAXRD). All the polymers show excellent thermal stability and the Tds was above 471°C. The intrinsic viscosities [?] of the polymers ranged from 0.8 to 0.9. The UV-Vis absorption peaks of the polymers in MSA were blue-shifted from 429 nm for PBO to 291 nm for PBOC7, and the Stokes shifts in PL spectra enlarged.
参考文献 |
相关文章 |
多维度评价
|
|
LiFePO/C cathode materials
synthesized by co-precipitation and microwave heating
XU Yunlong, TAO Lili, MA Hongyan, HUANG Huaqing
Frontiers of Chemical Engineering in China. 2008, 2 (4): 422-427.
https://doi.org/10.1007/s11705-008-0082-4
LiFePO4/C cathode materials were synthesized by a combination of co-precipitation and microwave heating using polyethylene glycol (PEG) as a carbon resource and the influence of microwave heating time on the structure and electrochemical performance of the materials was also discussed. The samples were characterized by X-ray diffraction (XRD), TEM, particle-size analysis and constant current charge-discharge experiment. The results show that the LiFePO4/C heated for 9 min has a pure olive-type phase and excellent electrochemical performance. The initial discharge capacities of this sample are 154.3, 139.7, 123.9 mAh/g at the rates 0.1C, 0.2C, 1C at room temperature, respectively, and after 20 cycles remain 152.3, 134.3, 118.5 mAh/g, respectively.
参考文献 |
相关文章 |
多维度评价
|
|
Synthesis, characterization and fluorescence
quenching of conjugated polymer containing triphenylamine group
LIU Feng, XIAO Jianhua, REN Weihua, HU Jun, LIU Honglai
Frontiers of Chemical Engineering in China. 2008, 2 (4): 428-433.
https://doi.org/10.1007/s11705-008-0083-3
Poly(triphenylamine-p-phenylenevinylene)s with two different end-groups were obtained through a Wittig polycondensation. The structures of two copolymers were characterized. Ultraviolet and visible spectroscopy (UV-Vis) and photoluminescence (PL) spectra show the end-capped polymer emits intensive green light in both solution and film state. Their applications in the detection of nitro compounds were investigated, and the results show high fluorescence quenching sensitivity of the end-capped polymer towards o-nitrotoluene (o-NT). When the concentration of o-NT was 21.5 × 10-3 mol/L, the fluorescence quenching reached 96%. Additionally, after the exposure of polymer film in three different quenchers such as dinitrotoluene (DNT), p-nitrobenzoquinone (p-BQ) and p-nitrotoluene (p-NT) for 600 s, its fluorescence quenching reached 93.6%, 11.5% and 77.9%, respectively. This kind of polymer has great advantages in preparation and may find applications in the detection of nitro explosives.
参考文献 |
相关文章 |
多维度评价
|
|
Enhancing thermostability of -mannanase by protective additives
LIU Zhaohui, QI Wei, WU Weina, LIU Yue, HE Zhimin
Frontiers of Chemical Engineering in China. 2008, 2 (4): 439-442.
https://doi.org/10.1007/s11705-008-0062-8
The effects of some sugars (glucose, mannose, fructose, sucrose and chitosan) and polyols (glycol, glycerol and sorbitol) as protective additive on the thermostability of ?-mannanase were studied. The optimal reaction temperatures of ?-mannanase and the thermodynamics and the deactivation kinetics with or without additives were also investigated. The experimental results show that sucrose, chitosan and sorbitol could apparently improve the thermal stability of ?-mannanase when their concentration was kept at 2 g/L. The optimal combination additive proportion was sucrose: chitosan : sorbitol = 1 : 2 : 2 (molar ratio) using the orthogonal experimental design. The sucrose, chitosan, glycerol, sorbitol and the combination additive might increase the optimal reaction temperature from 50°C to about 60°C due to their good protection effect. The thermal deactivation curves of ?-mannanase accorded with the kinetic rules of first order reaction, and the corresponding kinetic and thermodynamic parameters were calculated. Meanwhile, the protective mechanism of the additives against deactivation of enzyme was also discussed.
参考文献 |
相关文章 |
多维度评价
|
|
Studies on culture condition of new marine bacterium sp. SY01
LAN Wenjian, MO Linfeng, LI Houjin, CAI Chuanghua, ZHOU Yipin, YAO Junhua
Frontiers of Chemical Engineering in China. 2008, 2 (4): 443-446.
https://doi.org/10.1007/s11705-008-0065-5
New marine bacterium Zooshikella sp. SY01, producer of prodigiosin, was isolated from the seawaters of Sanya Bay. The culture conditions of this bacterium were investigated. Zooshikella sp. SY01 was cultured in 2216E media which contained tryptophan, histidine, lactonic acid, camphor, limonene, casein, diphenyl guanidine, coumarin and 1,3-dinitrobenzene, respectively. After 5 days cultivation, the extracts of different culture broths were detected by direct infusion mass spectroscopy using positive ESI mode. As the results, tryptophan, histidine and casein didn’t show any observable influences on the biosynthesis of prodigiosin. Lactonic acid, camphor, limonene, diphenyl guanidine, coumarin could inhibit the bacterium growth and prodigiosin biosynthesis to a certain extent, slower the culture broth to turn red. However, 1, 3-dinitrobenzene inhibited the bacteria to produce prodigiosin completely. MS data suggested that various metabolites with chemodiversity were produced in different culture media. In particular, a series of high-molecular-weight compounds with high relative abundances were observed in the medium containing limonene. To further optimize the culture condition, more new prodigiosin analogues and lead compounds can be obtained and the goal of “one strain-many compounds” can be achieved.
参考文献 |
相关文章 |
多维度评价
|
|
Study of simultaneous saccharification and fermentation
for steam exploded wheat straw to ethanol
LUO Peng, YANG Chuanmin, LIU Zhong, WANG Gaosheng
Frontiers of Chemical Engineering in China. 2008, 2 (4): 447-451.
https://doi.org/10.1007/s11705-008-0069-1
Although simultaneous saccharification and fermentation (SSF) has been investigated extensively, the optimum condition for SSF of wheat straw has not yet been determined. Dilute sulfuric acid impregnated and steam explosion pretreated wheat straw was used as a substrate for the production of ethanol by SSF through orthogonal experiment design in this study. Cellulase mixture (Celluclast 1.5 l and ?-glucosidase Novozym 188) were adopted in combination with the yeast Saccharomyces cerevisiae AS2.1. The effects of reaction temperature, substrate concentration, initial fermentation liquid pH value and enzyme loading were evaluated and the SSF conditions were optimized. The ranking, from high to low, of influential extent of the SSF affecting factors to ethanol concentration and yield was substrate concentration, enzyme loading, initial fermentation liquid pH value and reaction temperature, respectively. The optimal SSF conditions were: reaction temperature, 35°C; substrate concentration, 100 g·L-1; initial fermentation liquid pH, 5.0; enzyme loading, 30 FPU·g-1. Under these conditions, the ethanol concentration increased with reaction time, and after 72 h, ethanol was obtained in 65.8% yield with a concentration of 22.7 g·L-1.
参考文献 |
相关文章 |
多维度评价
|
|
Ethanol production from sweet sorghum residual
BAN Jingyang, YU Jianliang, ZHANG Xu, TAN Tianwei
Frontiers of Chemical Engineering in China. 2008, 2 (4): 452-455.
https://doi.org/10.1007/s11705-008-0072-6
In this work, the ethanol production from sweet sorghum residue was studied. Sweet sorghum residue was hydrolyzed with phosphoric acid under mild conditions. The liquid hydrolysate was fermented by Pachysolen tannophilus, and the hydrolysis residue was fermented by the simultaneous saccharification and fermentation (SSF) using Saccharomyces cerevisiae with cellulase (60 FPU/g dry materials). Orthogonal experiments were carried out to investigate the effects of main reaction condition factors, such as temperature, acid concentration, time and dry-matter content, on the reducing sugar yield. The results show that the optimal reaction conditions should be 120°C, 80 g/L, 80 min and 10%, respectively. Under these conditions, 0.3024 g reducing sugar/g dry material was obtained. The liquid hydrolysate was then fermented by P.tannophilus with the highest ethanol concentration of 14.5 g/L. At a water-insoluble solid concentration of 5%, 5.4 g/L ethanol was obtained after 12 h of SSF. The total ethanol yield was 0.147 g/g dry material, which would be beneficial for the application of ethanol production from sweet sorghum residue.
参考文献 |
相关文章 |
多维度评价
|
|
Properties and catalytic mechanism of -glutamyltranspeptidase from NX-2
WANG Qian, YAO Zhong, XUN Zhijing, XU Xiaoying, XU Hong, WEI Ping
Frontiers of Chemical Engineering in China. 2008, 2 (4): 456-461.
https://doi.org/10.1007/s11705-008-0075-3
Since ?-glutamyltranspeptidase (GGT) especially catalyses the transfer of the ?-glutamyl moiety to a variety of amino acids and short peptides, GGT has important practical value for enzymatic synthesis of ?-glutamyl compounds. In this paper, the GGT produced from Bacillus subtilis NX-2 was purified by a combination of ammonium sulfate fractionation and ion exchange chromatography, and the properties of purified GGT were investigated. At the conditions of pH 10.0, D-glutamine (D-Gln)/L-tryptophan (L-Trp) with a molar ratio of 5 : 7, a temperature 40°C and a reaction time of 4 h, a higher conversion rate of 42% was obtained. According to the time course, the catalytic mechanism of enzymatic synthesis of ?-D-glutamyl-L-tryptophan (?-D-Gln-L-Trp) was discussed. It was demonstrated that the GGT can catalyze not only the reaction of transpeptidation, but also the irreversible hydrolysis of the products which results in the decrease of the yield of the products. The affinity parameter of GGT to D-Gln (Km) was 5.08 mmol·L-1 and the maximum reaction rate of transpeptidation (rmax) was determined as 0.034 mmol·min-1·L-1, while the affinity parameter of GGT to ?-D-Gln-L-Trp (K’m) was 2.267 mmol·L-1, and the maximum reaction rate of hydrolysis (r’max) was 0.012 mmol·min-1·L-1.
参考文献 |
相关文章 |
多维度评价
|
|
Gas-solids separation model of a novel FCC riser
terminator device: super short quick separator (SSQS)
LU Chunxi, LI Ruxin, SHI Mingxian, LIU Xiancheng
Frontiers of Chemical Engineering in China. 2008, 2 (4): 462-467.
https://doi.org/10.1007/s11705-008-0068-2
The gas flow field and the separation efficiency of a novel fluid catalytic cracking (FCC) riser terminal device, named as Super Short Quick Separator (SSQS), were studied. On the basis of above investigations, a section-lateral-mixing separation model was proposed, which included both the effect of inertia and structure of gas outlet on particles capture. After final modification, the results predicted with this model could be in good agreement with the cold experimental data. According to this model, the separation efficiency of SSQS is mainly influenced by the difference between the arc radius and the center pipe radius as well as the magnitude of particle tangential velocity.
参考文献 |
相关文章 |
多维度评价
|
|
Development of solid base catalyst X/Y/MgO/-AlO for optimization of preparation of biodiesel from L.seed oil
WANG Rui, YANG Song, YIN Shitao, SONG Baoan, BHADURY Pinaki S., XUE Wei, TAO Shuwei, JIA Zhaohui, LIU Da, GAO Liang
Frontiers of Chemical Engineering in China. 2008, 2 (4): 468-472.
https://doi.org/10.1007/s11705-008-0074-4
The preparation and regeneration conditions of the identified catalyst X/Y/MgO/?-Al2O3 with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/?-Al2O3 . The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed with an oil/methanol molar ratio of 1 : 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214.
参考文献 |
相关文章 |
多维度评价
|
|
Preparation and adsorption performances of mesopore-enriched
bamboo activated carbon
WANG Yuxin, LIU Congmin, ZHOU Yaping
Frontiers of Chemical Engineering in China. 2008, 2 (4): 473-477.
https://doi.org/10.1007/s11705-008-0081-5
Activated carbon with high specific surface area and considerable mesopores was prepared from bamboo scraps by phosphoric acid activation. The effect of activation conditions was studied. Under the conditions of impregnating bamboo with 80% H3PO4 at 80°C for 9 days and activation at 500°C for 4 h, the prepared activated carbon had the highest mesopore volume of 0.67 cm3/g, a specific surface area of 1567 m2/g, and the mesopore ratio reached 47.18%. The study on adsorption isotherms of CH4, CO2, N2 and O2 on the activated carbon were carried out at 298 K. The considerable difference in the adsorption capacity between CO2 and the other gases was observed, which would be of interest for the adsorptive separation/purification of gaseous CO2 from its mixtures, especially from mixtures with N2 and/or O2.
参考文献 |
相关文章 |
多维度评价
|
23篇文章
|