共查询到19条相似文献,搜索用时 156 毫秒
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《现代化工》2017,(3)
以丙烯酸(AA)、魔芋葡甘聚糖(KGM)、腐植酸(HA)为原料,N,N'-二亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸钾(KPS)为引发剂,采用水溶液合成法制备具有半互穿网络结构的PAA/KGM/HA三元共聚吸水树脂。研究了丙烯酸中和度、单体配比、聚合温度、引发剂质量分数和交联剂质量分数对吸水树脂分别吸自来水和盐水的性能的影响,并对产物分别进行FTIR、SEM等表征测试。结果表明:当丙烯酸中和度为80%,温度为80℃,制备材料的最佳配比为m(AA)∶m(KGM)∶m(HA)∶w(APS)∶w(MBA)=10∶1.5∶0.1∶1.6%∶0.8%,此时吸自来水倍率最高可达1 012 g/g,吸盐水倍率为112 g/g,并且拥有较好的保水能力。 相似文献
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PVA/ P(AA-Co-AN)/ PVA渗透汽化膜的研究 总被引:1,自引:0,他引:1
制备一种PVA/P(AA-Co-AN)/PVA复合膜用于甲醇水溶液的分离,膜的主体部分P(AA-Co-AN)由添加纳米S iO2粉末的丙烯酸(AA)和丙烯腈(AN)通过溶液共聚制得,两侧为交联聚乙烯醇(PVA)。考察了复合膜在高质量分数甲醇水溶液中的溶胀性能,探讨了浸泡液温度及浸泡液质量分数对溶胀度的影响,测试了复合膜的力学性能。考察了不同单体配比〔n(AA)∶n(AN)〕所制备的复合膜在不同质量分数甲醇水溶液,不同温度下的渗透汽化性能。结果显示,复合膜在高质量分数甲醇水溶液中具有良好的溶胀性能及渗透汽化性能;在n(AA)∶n(AN)=1∶1下所制备的复合膜,对高质量分数甲醇水溶液分离效果最佳,60℃时分离w(甲醇)=98%的水溶液,分离因子可达1 534,通量为583 g/(m2.h)。 相似文献
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采用热法磷酸和尿素作为原料生产工业级磷酸脲。研究了磷酸浓度、反应时间、反应温度、磷酸与尿素物质的量比、结晶温度等条件对磷酸脲的氮、磷收率以及产品质量的影响。通过实验得到最佳工艺条件:磷酸中五氧化二磷质量分数为58%、反应时间为35 min、反应温度为80 ℃、尿素和磷酸物质的量比为1∶1、结晶温度为20 ℃。在最佳工艺条件下,产品磷酸脲中五氧化二磷质量分数为44.8%、氮质量分数为17.6%、纯度为99.7%,产品质量达到GB/T 27805—2011《工业磷酸脲》的要求;磷收率为85.7%,氮收率为86.0%。 相似文献
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湿法磷酸生产成本低,但杂质含量高,以湿法磷酸为原料制得的磷酸二氢钾(KDP)产品质量低。研究利用中和法,以杂质含量高的工业湿法磷酸为原料,制备柱状大颗粒磷酸二氢钾晶体。研究了螯合剂用量、降温速率和搅拌速率对磷酸二氢钾结晶过程的影响,考察了磷酸二氢钾的质量分数、收率、结晶速率和晶体形貌等指标,并进行了母液循环实验。研究结果表明:螯合剂能有效消除杂质离子对结晶过程的抑制作用。结晶的最适宜工艺条件为螯合剂用量0.70%、搅拌速率100 r·min-1、降温速率0.1℃·min-1。在此条件下得到的磷酸二氢钾晶体外观为柱状大颗粒,质量分数99.91%,平均粒度1.38 mm,结晶速率0.128 g·min-1,达到肥料级磷酸二氢钾优等品标准(HG/T 2321—2016);其中磷的单次收率49.86%。母液循环生产的磷酸二氢钾晶体质量分数、晶型和收率等指标全部达标。 相似文献
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通过实验研究玻璃基珠光颜料制备的最佳工艺条件,通过比较珠光颜料的白度最终确定:预处理的最佳工艺为采用质量浓度为5%的碳酸钠溶液以固液质量比1∶20在温度为40℃的条件下清洗24 h。对应于10 g玻璃鳞片,制备玻璃基珠光颜料方法:加入1 ml的四氯化锡和2 ml硅烷;尿素的加入量为15 g,加入方式为将尿素的80%一次性加入到玻璃鳞片悬浮液中,20%加入到四氯化钛溶液中;水解的最佳温度为90℃;四氯化钛溶液的加入量为30 ml,钛液滴加速度为0.5 ml/min;煅烧的最优条件为500℃下煅烧2 h。 相似文献
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M. Cartens E. Molina Grima A. Robles Medina A. Giménez Giménez J. Ibáñez González 《Journal of the American Oil Chemists' Society》1996,73(8):1025-1031
Eicosapentaenoic acid (EPA, 20∶5n-3) was obtained from the marine microalgaePhaeodactylum tricornutum by a three-step process: fatty acid extraction by direct saponification of biomass, polyunsaturated fatty acid (PUFA) concentration
by formation of urea inclusion compounds, and EPA isolation by semipreparative high-performance liquid chromatography (HPLC).
Alternatively, EPA was obtained by a similar two-step process without the PUFA concentration step by the urea method. Direct
saponification of biomass was carried out with two solvents that contained KOH for lipid saponification. An increase in yield
was obtained because the problems associated with emulsion formation were avoided by separating the biomass from the soap
solution before adding hexane for extraction of insaponifiables. The most efficient solvent, ethanol (96%) at 60°C for 1 h,
extracted 98.3% of EPA. PUFA were concentrated by the urea method with a urea/fatty acid ratio of 4∶1 at a crystallization
temperature of 28°C and by using methanol and ethanol as urea solvents. An EPA concentration ratio of 1.73 (55.2∶31.9) and
a recover yield of 78.6% were obtained with methanol as the urea solvent. This PUFA concentrate was used to obtain 93.4% pure
EPA by semipreparative HPLC with a reverse-phase, C18, 10 mm i.d.×25-cm column and methanol/water (1% acetic acid), 80∶20 w/w, as the mobile phase. Eighty-five percent of EPA
loaded was recovered, and 65.7% of EPA present inP. tricornutum biomass was recovered in highly pure form by this three-step downstream process. Alternatively, 93.6% pure EPA was isolated
from the fatty acid extract (without the PUFA concentration step) with 100% EPA recovery yield. This two-step process increases
the overall EPA yield to 98.3%, but it is only possible to obtain 20% as much EPA as that obtained by three-step downstream
processing. 相似文献
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A. Robles Medina A. Giménez Giménez F. García Camacho J. A. Sánchez Pérez E. Molina Grima A. Contreras Gómez 《Journal of the American Oil Chemists' Society》1995,72(5):575-583
n-3 Polyunsaturated fatty acids (n-3 PUFA) from the marine microalgaIsochrysis galbana were concentrated and purified by a two-step process—formation of urea inclusion compounds followed by preparative high-performance
liquid chromatography. These methods had been developed previously with fatty acids from cod liver oil. By the urea inclusion
compounds method, a mixture that contained 94% (w/w) stearidonic (SA), eicosapentaenoic (EPA), plus docosahexaenoic (DHA)
acids (4:1 urea/fatty acid ratio and 4°C crystallization final temperature) was obtained from cod liver oil fatty acids. Further
purification of SA, EPA, and DHA was achieved with reverse-phase C18 columns. These isolations were scaled up to a semi-preparative column. A PUFA concentrate was isolated fromI. galbana with methanol/water (80:20, w/w) or ethanol/water (70:30, w/w). With methanol/water, a 96% EPA fraction with 100% yield was
obtained, as well as a 94% pure DHA fraction with a 94% yield. With ethanol/water as the mobile phase, EPA and DHA fractions
obtained were 92% pure with yields of 84 and 88%, respectively. 相似文献
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Monjurul Haq Adane Tilahun Getachew Periaswamy Sivagnanam Saravana Yeon-Jin Cho Seul-Ki Park Min-Jung Kim Byung-Soo Chun 《Korean Journal of Chemical Engineering》2017,34(8):2255-2264
Supercritical carbon dioxide (SC-CO2) extracted Atlantic salmon frame bone oil (SFBO) was used for Eicosapentaenoic acid and Docosahexaenoic acid (EPA-DHA) concentrate production by urea complexation. Urea/fatty acids (2.5 to 4.0 w/w), crystallization temperature (?24 to ?8 °C) and crystallization time (8 to 24 h) were studied by Box-Behnken Design (BBD) to maximize EPA-DHA content. Highest EPA-DHA content was 60.63% at urea/fatty acids 4.0 w/w, crystallization temperature ?15.67 °C and crystallization time 8 h. EPA-DHA concentrate showed improvement of EPA-DHA from 6.39% in SFBO to 62.34%, increase of astaxanthin content from 21.33 μg/g in SFBO to 44.69 μg/g in EPA-DHA concentrate, no residual urea and reduction of many off-flavor compounds. The EPA-DHA yield showed an inverse relation with the urea/fatty acids, whereas its concentration increased proportionally with urea/fatty acids. Therefore, EPA-DHA concentrate produced from SFBO by urea complexation may be an efficient technique to provide ω-3 polyunsaturated fatty acids to the consumers. 相似文献
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以混合脂肪酸甲酯为原料,采用尿素包合法(脲包法)分离不饱和脂肪酸甲酯。通过正交试验,得到了最佳工艺条件:混合脂肪酸甲酯(w):尿素(w):甲醇(v)为1:2.09:8.36,包合温度-10℃,包合时间18h。经过一次包合,不饱和脂肪酸甲酯的含量由原来的47.69%提高到86.74%,收率54.19%。 相似文献
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采用甲醇溶剂法分离蚕蛹油多不饱和脂肪酸。通过单因素实验探讨了温度、甲醇浓度、甲醇脂肪比、时间对多不饱和脂肪酸分离效果的影响,然后通过正交实验确定了多不饱和脂肪酸分离的较佳条件。结果表明,适宜的分离条件为:温度-10℃,甲醇浓度90%(w),甲醇脂肪比2.5,结晶时间30min,在上述条件下多不饱和脂肪酸得率为62.3%,含量由71.0%提高到95.8%。 相似文献