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351.
乙酸正丁酯的绿色合成   总被引:1,自引:1,他引:1  
以乙酸和正丁醇为原料,十二水合硫酸铁铵替代浓硫酸为催化剂对文题合成实验进行改进,考察了酸醇物质的量、催化剂用量、反应时间等对酯化率的影响。实验结果表明,最佳的反应条件为:乙酸和正丁醇的摩尔比1∶1.2,催化剂的用量1.1 g,反应时间45 min,酯化率可达98%以上。该催化剂廉价易得、性质稳定、不溶于有机酸和有机醇,反应后结成不溶块状物,很容易从反应体系中分离,催化活性好,选择性高,对仪器设备无腐蚀。改进后的实验廉价、绿色、易操作,对工业生产及实验教学有积极的指导意义。  相似文献   
352.
采用Tafel极化曲线法和电化学交流阻抗谱法测定不同浓度缓蚀剂在0.2 mol·L-1乙酸介质中对冷轧钢的缓蚀作用.结果表明:在20℃、0.2 mol·L-1乙酸溶液中二乙基二硫代氨基甲酸钠对冷轧钢具有较好的缓蚀效果,缓蚀率随着缓蚀剂浓度的增加而增大,当缓蚀剂的浓度为3×10-3 mol·L-1时,缓蚀率达到85%,属于阴极型缓蚀剂.二乙基二硫代氨基甲酸钠在冷轧钢表面的吸附符合Langmuir吸附等温式,其吸附为自发进行的物理和化学吸附.  相似文献   
353.
The okra germplasm was screened for salinity tolerance at the seedling stage and during plant ontogeny. Substantial variation existed in okra for salinity tolerance at the seedling stage. An 80 mmol/L NaCl concentration was suitable for discriminating tolerant and non-tolerant okra genotypes. The pooled ranking of the genotypes, based on individual rankings for each trait (root and shoot length, germination percentage, and relative Na+ and K+) in individual NaCl concentrations, was effective for selecting tolerant genotypes. Genotypes selected at the seedling stage maintained their tolerance to NaCl during plant ontogeny, suggesting that screening of the germplasm entries and advanced breeding materials for salt tolerance at the seedling stage is effective. Among 39 okra genotypes, five were identified as the most tolerant genotypes and showed potential for use in breeding programs that focus on the development of salt-tolerant, high-yield okra cultivars.  相似文献   
354.
三种金属有机化合物作为客体交换嵌入层状磷锑酸钠层间,采用浸渍法制备,并采用TGA、IR、XRD等方法对其进行了表征,表明采用层状化合物有望获得有利于反应组分进出的分子空间通道.层状磷锑酸盐的层膨胀、回缩可逆、原有层结构不被破坏.嵌接担载大大改善了催化材料CuSb3bP2O14(Na)的抗失活稳定性,磷锑酸层间基因和静电场的协同作用改善了它的催化效果.  相似文献   
355.
以木薯淀粉为原料,高碘酸钠作氧化剂在拟均相体系中制备了双醛淀粉,研究了反应时间、反应温度、高碘酸钠的浓度、反应pH值、高碘酸钠与淀粉摩尔对产品中双醛含量的影响。在选定的实验范围内,制得了双醛含量在64.1%~90.3%的双醛淀粉。  相似文献   
356.
为使竹原佛针织物在漂白工艺中实现“节能减排”、“清洁生产”、“绿色环保”,探讨了竹原,棉针织物用过碳酸钠与卜公茶皂素漂白的漂白原理,选取竹原/棉针织物的白度、毛细管效应和强力为研究对象,以过碳酸钠与卜公茶皂素为漂白剂,通过浸渍工艺分别对其进行漂白,对其性能指标进行了一系列的测试.结果表明:卜公茶皂素对竹原/棉针织物的漂白效果优于过碳酸钠,卜公茶皂素漂白工艺温和,符合国际上倡导的“节能减排”、“清洁生产”、“绿色环保”的产业发展政策,可实现人类社会的低碳生活.  相似文献   
357.
This randomized controlled trial compared the effectiveness of traditional lecture (C), face‐to‐face demonstration (DP), on‐line lecture capture (OP), and the combination of the last two (OP+DP) to enhance culinary arts students' application skills related to sodium usage in food preparation. Objectives were to compare relative effectiveness of the four instructional methods with respect to knowledge about dietary sodium, ease of use of sodium reduction techniques, strategies to reduce sodium and attitudes about use of dietary sodium in cooking; and to compare student satisfaction with the instructional methods. A convenience sample of n = 139 students was randomized to receive the C, DP, OP, or OP+DP intervention. To measure effectiveness of each instructional method, a nutrition survey was administered as a pre‐test, post‐test, and an eight‐week follow‐up. There was no statistically significant difference in performance between DP, OP, and OP+DP groups on each subscale. However, each of these methods performed significantly better than the control group (C). DP, OP, and OP+DP methods were superior to the control group (C). In general, OP+DP resulted in the largest effect sizes, suggesting that this intervention was possibly more effective as compared to the OP or DP. Future culinarians can benefit from learning about health‐conscious sodium reduction cooking practices as seen in the nutrition education sector to improve population health.  相似文献   
358.
目的:建立乳酸左氧氟沙星氯化钠注射液中主药的含量测定方法。方法:采用反相高效液相色谱法。以Lichrospher5-C18为色谱柱;己烷磺酸钠-甲醇(3:1)为流动相;流速为1.0ml/min;检测波长为293nm,柱温为40℃,进样量为20u1。结果:乳酸左氧氟沙星浓度在5.0-50.0μg/ml内线性关系良好(r=0.9995),平均回收率为99.85%。RSD为0.25%。结论:此法准确可靠,重现性好,能有效控制乳酸左氧氟沙星氯化钠注射液的质量。  相似文献   
359.
ZiO2 was prepared by the hydrolyzation method in (NH4)2SO4-modified TiCl4 solution, and TiO2 photocatalysts were obtained by accelerating the precipitation of TiO2 powder in a high-temperature water bath. The photocatalysts were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Raman spectrum and UV-Vis (Ultraviolet-Visible) spectrometry techniques, and the photocatalytic activity in phenol-contaminated water was investigated. The results showed that photocatalysts calcined at 400 ℃ had a specific surface area of 138.2 m^2/g and an average particle size of 9 nm, and a significant increase in thermal stability of anatase phase. At the calcination temperature of 700 ~C, the crystal form of TiO2 started to change into rutile (anatase: 97%, rutile: 3%). The activity of TiO2 photocatalysts prepared with (NH4)2SO4-modified TIC14 solution was markedly stronger than that without (NH4)2SOg-modified TIC14 solution. Maximal photocatalytic activity was observed at the mole ratio of Ti:(NH4)2SO4= 1:2, the water-bath temperature of 90℃ and the calcination temperature of 700 ℃.  相似文献   
360.
氨浸法制取饲料级硫酸铜   总被引:3,自引:0,他引:3  
本工艺以氨水浸取原料中CuO形式的铜。有较高的浸出率。CuO的浸出率达 90 %以上。通过蒸氨将 [Cu(NH3) 4] 2 +转化为CuO ,将CuO溶于稀H2 SO4 母液 ,结晶后可生产出符合国家标准的饲料级CuSO4 ·5H2 O产品。  相似文献   
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