A novel Co-B amorphous alloy catalyst in the form of ultrafine particles was prepared by chemical reduction of CoCl2 with aqueous NaBH4, which exhibited excellent activity and selectivity during the hydrogenation of c...A novel Co-B amorphous alloy catalyst in the form of ultrafine particles was prepared by chemical reduction of CoCl2 with aqueous NaBH4, which exhibited excellent activity and selectivity during the hydrogenation of cinnamaldehyde to cinnamyl alcohol in liquid phase. The optimum yield of cinnamyl alcohol was 87.6%, much better than the yield of using Raney Ni, Raney Co and other Co-based catalysts.展开更多
The ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4. During liquidphase hydrogenation of cinnamaldehyde at atmospheric pressure, the Ru-B catalyst prepared exhibited excellent sele...The ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4. During liquidphase hydrogenation of cinnamaldehyde at atmospheric pressure, the Ru-B catalyst prepared exhibited excellent selectivity to cinnamyl alcohol. When the hydrogenation was performed with ultrasonic irradiation, the reaction rate could be greatly enhanced while the selectivity to cinnamyl alcohol remained almost unchanged. The hydrogenation rate was increased with the increase of either the ultrasonic frequency or the irradiation time. According to various characterizations, such as XRD, XPS, TEM, BET and ICP, the effect of ultrasonic irradiation on the structural and electronic characteristics of Ru-B catalyst was studied briefly. Meanwhile, the promotion effect of ultrasonication on the catalytic performance was also discussed based on the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol.展开更多
The liquid phase selective hydrogenation of cinnamaldehyde has been investigated over the catalysts Co-C-T(T=400-700℃),which were derived from the carbonization of the MOF precursor Co-BTC at different temperatures i...The liquid phase selective hydrogenation of cinnamaldehyde has been investigated over the catalysts Co-C-T(T=400-700℃),which were derived from the carbonization of the MOF precursor Co-BTC at different temperatures in inert atmosphere.Co-C-500 exhibited a higher conversion(85.3%)than those carbonized at other temperatures,with 51.5%selectivity to cinnamyl alcohol,under a mild condition(90℃,4 h,2 MPa H_(2),solvent:9 ml ethanol and 1 ml water).The high catalytic activity of Co-C-500 can be ascribed to the large specific surface area of the catalyst,the uniformly dispersed metallic cobalt nanoparticles,and the more defect sites on the carbon support.Moreover,Co-C-500 showed excellent reusability in 5 successive cycles,mainly related to the uniformly dispersed cobalt nanoparticles embedded in carbon support.展开更多
以一水柠檬酸和六水硝酸钴为原料,采用水热-碳化联合法制备碳包覆纳米金属钴催化剂。通过调变原料比例和碳化温度,得到优选催化剂Co-CA_(2.5)-500。将制备的催化剂用于肉桂醛选择加氢反应,表现出优异的催化性能,在70℃、2 MPa H_(2)条件...以一水柠檬酸和六水硝酸钴为原料,采用水热-碳化联合法制备碳包覆纳米金属钴催化剂。通过调变原料比例和碳化温度,得到优选催化剂Co-CA_(2.5)-500。将制备的催化剂用于肉桂醛选择加氢反应,表现出优异的催化性能,在70℃、2 MPa H_(2)条件下,以9 mL EtOH+1 mL H_(2)O为溶剂反应2 h,肉桂醛转化率为75.1%,肉桂醇选择性为64.7%。表征结果表明,Co-CA_(2.5)-500的高催化性能与碳载体发达的孔道结构和活性金属钴的高度分散有关。展开更多
目的探讨内镜下聚桂醇硬化剂局部注射治疗Ⅱ~Ⅲ期内痔患者的临床效果。方法选取2019年3月—2021年3月普宁华侨医院120例内痔患者,依据随机数表法分为对照组和观察组,每组60例,对照组实施吻合器痔上黏膜环切术(procedure for prolapse an...目的探讨内镜下聚桂醇硬化剂局部注射治疗Ⅱ~Ⅲ期内痔患者的临床效果。方法选取2019年3月—2021年3月普宁华侨医院120例内痔患者,依据随机数表法分为对照组和观察组,每组60例,对照组实施吻合器痔上黏膜环切术(procedure for prolapse and hemorrhoid,PPH)治疗,观察组实施内镜下聚桂醇硬化剂局部注射治疗,比较两组患者临床疗效、手术一般情况、肛周疼痛程度、并发症以及复发率。结果观察组总有效率95.00%高于对照组,差异有统计学意义(χ^(2)=4.227,P<0.05);术前,两组患者视觉模拟评分法(visual analogue scale,VAS)对比,差异无统计学意义(P>0.05),观察组术后1、3、5 d VAS评分均低于对照组,差异有统计学意义(P<0.05)。结论内镜下聚桂醇硬化剂局部注射用于Ⅱ~Ⅲ期内痔患者的治疗,可改善术后一般情况,减轻疼痛,提高疗效,不增加并发症发生率以及复发率。展开更多
基金This work was supported by the National Natural Science Foundation of China (29973025) and the Natural Science Foundation of Shanghai Science and Technology Committee (98QMA11402).
文摘A novel Co-B amorphous alloy catalyst in the form of ultrafine particles was prepared by chemical reduction of CoCl2 with aqueous NaBH4, which exhibited excellent activity and selectivity during the hydrogenation of cinnamaldehyde to cinnamyl alcohol in liquid phase. The optimum yield of cinnamyl alcohol was 87.6%, much better than the yield of using Raney Ni, Raney Co and other Co-based catalysts.
基金Project supported by the National Natural Science Foundation of China （No. 20377031）, the Shanghai Leading Academic Discipline Project （No, T0402）, the Natural Science Foundation of Shanghai Science and Technology Committee （Nos, 02DJ14051, 0452nrn070, 05QMX1442, 0552nm036）, and the Shanghai Eduction Committee （No, 05DZ20）.
文摘The ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4. During liquidphase hydrogenation of cinnamaldehyde at atmospheric pressure, the Ru-B catalyst prepared exhibited excellent selectivity to cinnamyl alcohol. When the hydrogenation was performed with ultrasonic irradiation, the reaction rate could be greatly enhanced while the selectivity to cinnamyl alcohol remained almost unchanged. The hydrogenation rate was increased with the increase of either the ultrasonic frequency or the irradiation time. According to various characterizations, such as XRD, XPS, TEM, BET and ICP, the effect of ultrasonic irradiation on the structural and electronic characteristics of Ru-B catalyst was studied briefly. Meanwhile, the promotion effect of ultrasonication on the catalytic performance was also discussed based on the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol.
基金financial support from the National Natural Science Foundation of China(22272016).
文摘The liquid phase selective hydrogenation of cinnamaldehyde has been investigated over the catalysts Co-C-T(T=400-700℃),which were derived from the carbonization of the MOF precursor Co-BTC at different temperatures in inert atmosphere.Co-C-500 exhibited a higher conversion(85.3%)than those carbonized at other temperatures,with 51.5%selectivity to cinnamyl alcohol,under a mild condition(90℃,4 h,2 MPa H_(2),solvent:9 ml ethanol and 1 ml water).The high catalytic activity of Co-C-500 can be ascribed to the large specific surface area of the catalyst,the uniformly dispersed metallic cobalt nanoparticles,and the more defect sites on the carbon support.Moreover,Co-C-500 showed excellent reusability in 5 successive cycles,mainly related to the uniformly dispersed cobalt nanoparticles embedded in carbon support.
文摘以一水柠檬酸和六水硝酸钴为原料,采用水热-碳化联合法制备碳包覆纳米金属钴催化剂。通过调变原料比例和碳化温度,得到优选催化剂Co-CA_(2.5)-500。将制备的催化剂用于肉桂醛选择加氢反应,表现出优异的催化性能,在70℃、2 MPa H_(2)条件下,以9 mL EtOH+1 mL H_(2)O为溶剂反应2 h,肉桂醛转化率为75.1%,肉桂醇选择性为64.7%。表征结果表明,Co-CA_(2.5)-500的高催化性能与碳载体发达的孔道结构和活性金属钴的高度分散有关。
文摘目的探讨内镜下聚桂醇硬化剂局部注射治疗Ⅱ~Ⅲ期内痔患者的临床效果。方法选取2019年3月—2021年3月普宁华侨医院120例内痔患者,依据随机数表法分为对照组和观察组,每组60例,对照组实施吻合器痔上黏膜环切术(procedure for prolapse and hemorrhoid,PPH)治疗,观察组实施内镜下聚桂醇硬化剂局部注射治疗,比较两组患者临床疗效、手术一般情况、肛周疼痛程度、并发症以及复发率。结果观察组总有效率95.00%高于对照组,差异有统计学意义(χ^(2)=4.227,P<0.05);术前,两组患者视觉模拟评分法(visual analogue scale,VAS)对比,差异无统计学意义(P>0.05),观察组术后1、3、5 d VAS评分均低于对照组,差异有统计学意义(P<0.05)。结论内镜下聚桂醇硬化剂局部注射用于Ⅱ~Ⅲ期内痔患者的治疗,可改善术后一般情况,减轻疼痛,提高疗效,不增加并发症发生率以及复发率。
