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本文介绍了SO_4~2/TiO_2固体超强酸催化剂用于催化松香甘油酯化反应,发现催化活性高于传统的ZnO催化剂。本文系统地考察了催化剂制备条件(灼烧温度、淋洗液、沉淀方式等对催化剂催化性能的影响,结果表明,反加法沉淀、(NH_4)_2SO_4淋洗、525℃灼烧所得催化剂的效果最佳。 相似文献
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Chunjie Zhu Baishan Fang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(5):853-857
BACKGROUND: The purpose of the present work was to enhance 1,3‐propanediol productivity during the batch cultivation on a type of raw glycerol by application of a two‐stage temperature control strategy. RESULTS: First, the effect of the raw glycerol on microbial growth and 1,3‐propanediol production was investigated. The highest 1,3‐propanediol productivity, 1.93 g L?1 h?1, was achieved when the initial raw glycerol concentration was 6% (v/v). Second, the effect of temperature on microbial growth and 1,3‐propanediol production was investigated and kinetic analysis was carried out. The results indicated that 37 °C favored microbial growth while 35 °C was best for 1,3‐propanediol production. Finally, a two‐stage temperature control strategy was applied in 1,3‐propanediol production. The incubation temperature was kept at 37 °C from inoculation to 2 h and then switched to 35 °C. Compared with batch cultivations at 35 and 37 °C, the fermentation time was shortened from 10 to 9.2 h, resulting in an increase in 1,3‐propanediol productivity of around 11%. CONCLUSION: 1,3‐propanediol productivity was enhanced effectively by application of a two‐stage temperature control strategy. © 2012 Society of Chemical Industry 相似文献
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Shayan Naghizadeh Nahid Hassanzadeh Nemati Alireza Hassani Najafabadi Hassan Niknejad 《国际聚合物材料杂志》2018,67(4):212-220
A blend of polyglycerol sebacate-poly ethylene glygol/chitosan-poly ethylene glycol-coated iron oxide (PGS-PEG/CS-PEG@Fe3O4) nanoparticles for 5FU delivery was prepared by reverse ultrasonic emulsification method. To enhance polymers’ solubility, PEG was grafted. Chemical characterization was performed through Fourier transformed infrared and proton nuclear magnetic resonance spectra. In vitro assay revealed that release profile of 5FU-loaded PGS-PEG/CS-PEG@Fe3O4 is sustained. Moreover, cytotoxicity was analyzed on HT29 cell line at the presence of external magnetic field using the lactate dehydrogenase and Alamar Blue. Results illustrate that (PGS-PEG/CS-PEG@Fe3O4) is promising to use as a carrier for 5FU anticancer agent with sustained tailored release. 相似文献
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《大分子材料与工程》2017,302(10)
Polyacrylamide usually is the material of choice for electrophoretic separation in slab gels, capillaries, and microfluidic devices. So far its polymerization requires anaerobic environments because oxygen impurities inhibit or even terminate the polymerization reaction of acrylamide. Here, it is demonstrated that gel precursor solutions with glycerol contents above 20 vol% enable direct atmospheric photopolymerization of acrylamide with no need for sealing or degassing the solution in advance. The positive effect of glycerol on the polymerization reaction is proven by simulation‐validated electron paramagnetic resonance measurements. Nuclear magnetic resonance reveals that glycerol does not interfere with the reaction indicating that the observed enhancement in polymerization is owed to the low oxygen solubility of aqueous glycerol mixtures. Glycerol concentrations of >60 vol% in the gel precursor solution enable complete polymerization of volumes down to 5 nL within less than 5 s. This enables using liquid handling robots to fabricate channel‐free open microfluidic structures of solid polyacrylamide hydrogel in a low‐cost automated manner in a standard lab environment. 相似文献