针对Φ273.05×7.09 mm H40 SC直缝焊套管螺纹的一次加工问题展开研究,分析当前该工艺在加工过程中存在的问题,探讨影响加工质量的关键因素,并提出针对性的改进方案。验证结果表明,改进方案具有显著的有效性,可提升生产效率和产品...针对Φ273.05×7.09 mm H40 SC直缝焊套管螺纹的一次加工问题展开研究,分析当前该工艺在加工过程中存在的问题,探讨影响加工质量的关键因素,并提出针对性的改进方案。验证结果表明,改进方案具有显著的有效性,可提升生产效率和产品质量。展开更多
An Hβ-supported heteropoly acid （H3PW12O40 （HPW）/Hβ） catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-...An Hβ-supported heteropoly acid （H3PW12O40 （HPW）/Hβ） catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-butyltoluene （PTBT）. X-ray diffraction, scanning electron microscopy, transmis- sion electron microscopy, fourier-transform infrared spectroscopy, inductively coupled plas- ma-optical emission spectrometry, the brunauer emmett teller （BET） method, tempera- ture-programmed NH3 desorption, and pyridine adsorption infrared spectroscopy were used to characterize the catalyst. The results showed that loading HPW on Hβ effectively increased the B acidity and decreased the pore size of Hβ. The B acidity of HPW/Hβ was 142.97 μmol/g, which is 69.74% higher than that of Hβ （84.23 μmol/g）. The catalytic activity of the HPW/Hβ catalyst was much better than that of the parent Hβ zeolite because of its high B acidity. The toluene conversion over HPW/Hβ reached 73.1%, which is much higher than that achieved with Hβ （54.0%）. When HPW was loaded on Hβ, the BET surface area of Hβ decreased from 492.5 to 379.6 m2/g, accompa- nied by a significant decrease in the pore size from 3.90 to 3.17 nm. Shape selectivity can therefore play an important role and increase the product selectivity of the HPW/Hβ catalyst compared with that of the parent Hβ. PTBT （kinetic diameter 0.58 nm） can easily diffuse through the narrowed pores of HPW/Hβ, but 3-tert-butyltoluene （kinetic diameter 0.65 nm） diffusion is restricted because of steric hindrance in these narrow pores. This results in high PTBT selectivity over HPW/Hβ （around 81%）. The HPW/Hβ catalyst gave a stable catalytic performance in reusability tests.展开更多
基金supported by the National Key Basic Research Program of China(973)(2010CB226903)National Natural Science Foundation of China(21073147,21303140)Program for Changjiang Scholars and Innovative Research Team in University,China(IRT1036)~~
文摘An Hβ-supported heteropoly acid （H3PW12O40 （HPW）/Hβ） catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-butyltoluene （PTBT）. X-ray diffraction, scanning electron microscopy, transmis- sion electron microscopy, fourier-transform infrared spectroscopy, inductively coupled plas- ma-optical emission spectrometry, the brunauer emmett teller （BET） method, tempera- ture-programmed NH3 desorption, and pyridine adsorption infrared spectroscopy were used to characterize the catalyst. The results showed that loading HPW on Hβ effectively increased the B acidity and decreased the pore size of Hβ. The B acidity of HPW/Hβ was 142.97 μmol/g, which is 69.74% higher than that of Hβ （84.23 μmol/g）. The catalytic activity of the HPW/Hβ catalyst was much better than that of the parent Hβ zeolite because of its high B acidity. The toluene conversion over HPW/Hβ reached 73.1%, which is much higher than that achieved with Hβ （54.0%）. When HPW was loaded on Hβ, the BET surface area of Hβ decreased from 492.5 to 379.6 m2/g, accompa- nied by a significant decrease in the pore size from 3.90 to 3.17 nm. Shape selectivity can therefore play an important role and increase the product selectivity of the HPW/Hβ catalyst compared with that of the parent Hβ. PTBT （kinetic diameter 0.58 nm） can easily diffuse through the narrowed pores of HPW/Hβ, but 3-tert-butyltoluene （kinetic diameter 0.65 nm） diffusion is restricted because of steric hindrance in these narrow pores. This results in high PTBT selectivity over HPW/Hβ （around 81%）. The HPW/Hβ catalyst gave a stable catalytic performance in reusability tests.
