A carbon solid acid catalyst was prepared by the sulfonation of partially carbonized peanut shell with concentrated H2SO4. The structure and acidity of the catalyst were characterized by Fourier transform infrared spe...A carbon solid acid catalyst was prepared by the sulfonation of partially carbonized peanut shell with concentrated H2SO4. The structure and acidity of the catalyst were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and elemental analysis, which showed that it was an amorphous carbon material composed of aromatic carbon sheets in random orientations. Sulfonic acid groups were present on the surface at a density of 0.81 mmol/g. The carbon solid acid catalyst showed better performance than HZSM‐5 for the esterification of cyclohexene with formic acid. At a3:1 molar ratio of formic acid to cyclohexene, catalyst loading of 0.07 g/mL of cyclohexene, and reaction time of 1 h at 413 K, the cyclohexene conversion was 88.4% with 97.3% selectivity to cyclohexyl formate. The carbon solid acid catalyst showed better reusability than HZSM‐5 because its large pores were minimally affected by the accumulation of oligomerized cyclohexene, which deactivated HZSM‐5. The activity of the carbon solid acid catalyst decreased somewhat in the first two recycles due to the leaching of polycyclic aromatic hydrocarbon containing –SO3H groups and then it remained constant in the following reuse.展开更多
Two kinds of mesoporous carbon solid acids(LDMCE-SO3H and LDMCS-SO3H)were successfully prepared using masson pine alkali lignin as carbon source by evaporation-induced self-assembly(EISA)and salt-induced selfassembly(...Two kinds of mesoporous carbon solid acids(LDMCE-SO3H and LDMCS-SO3H)were successfully prepared using masson pine alkali lignin as carbon source by evaporation-induced self-assembly(EISA)and salt-induced selfassembly(SISA)followed by sulfonation,respectively.In terms of preparation process,SISA(self-assembly in water and preparation time of 2 days)is greener and simpler than EISA(self-assembly in ethanol and preparation time of 7 days).The prepared LDMCE-SO3H and LDMCS-SO3H exhibit obvious differences in structural characteristics such as pore channel structure,specific surface area,mesopore volume and the density of-SO3H groups.Furthermore,the catalytic performances of LDMCE-SO3H and LDMCS-SO3H were investigated in the hydrolysis of microcrystalline cellulose in water,and the glucose yields of 48.99%and 54.42%were obtained under the corresponding optimal reaction conditions.More importantly,the glucose yields still reached 28.85%and 30.35%after five runs,and restored to 39.02%and 45.98%through catalysts regeneration,respectively,demonstrating that LDMCE-SO3H and LDMCS-SO3H have excellent recyclability and regenerability.展开更多
The synthesis of 2, 4-diisopropyl-5,5-dimethy1- 1.3-dioxane through the acetalization of isobutyraldehyde with 2, 2, 4-trimethy1-1,3-pentanediol (TMPD) catalyzed by the novel carbon based acid was first carried out....The synthesis of 2, 4-diisopropyl-5,5-dimethy1- 1.3-dioxane through the acetalization of isobutyraldehyde with 2, 2, 4-trimethy1-1,3-pentanediol (TMPD) catalyzed by the novel carbon based acid was first carried out. High conversion (≥98%) and specific selectivity were obtained using the novel carbon based acid, which kept high activity after it was reused 5 times. Moreover. the catalyst could be used to catalyze the acetalization and ketalization of different aldehydes and ketones with superior yield. The yield of several products was over 90%. The novel heterogeneous catalyst has the distinct advantages of high activity, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the success of the green process greatly.展开更多
In this work, a new sample pretreatment method prior to HPLC separations was developed for the determination of auxins in plant samples, Owing to its large surface area and high adsorption capacity, multi-walled carbo...In this work, a new sample pretreatment method prior to HPLC separations was developed for the determination of auxins in plant samples, Owing to its large surface area and high adsorption capacity, multi-walled carbon nanotube (MWCNT) was chosen as the adsorbent for the extraction of auxins from plant samples. In this study, two important auxins were selected as model analytes, namely indole-3- butyric acid (IBA) and 1-naphthylacetic acid (NAA). They could be extracted and concentrated due to their π-π stacking interactions with MWCNT. Then HPLC-UV was introduced to detect IBA and NAA after sample pretreatment. Factors that may affect the enrichment efficiency were investigated and optimized. Comparative studies showed that MWCNT was superior to CI 8 for the extraction of the two analytes. Validation experiments showed that the optimized method had good linearity (0.9998 and 0.9960), high recovery (81.4%-85.4%), and low detection limits (0.0030 mg/L and 0.0012 mg/L). The results indicated that the novel method had advantages of convenience, good sensitivity, high efficiency, and it was feasible for the determination of auxins in plant samples.展开更多
基金supported by the National Natural Science Foundation of China(2123600121176056)+1 种基金the Programme for 100 Excellent Talents in Universities of Hebei Province(II)(BR2-208)the Natural Science Foundation of Hebei Province(B2015202228)~~
文摘A carbon solid acid catalyst was prepared by the sulfonation of partially carbonized peanut shell with concentrated H2SO4. The structure and acidity of the catalyst were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and elemental analysis, which showed that it was an amorphous carbon material composed of aromatic carbon sheets in random orientations. Sulfonic acid groups were present on the surface at a density of 0.81 mmol/g. The carbon solid acid catalyst showed better performance than HZSM‐5 for the esterification of cyclohexene with formic acid. At a3:1 molar ratio of formic acid to cyclohexene, catalyst loading of 0.07 g/mL of cyclohexene, and reaction time of 1 h at 413 K, the cyclohexene conversion was 88.4% with 97.3% selectivity to cyclohexyl formate. The carbon solid acid catalyst showed better reusability than HZSM‐5 because its large pores were minimally affected by the accumulation of oligomerized cyclohexene, which deactivated HZSM‐5. The activity of the carbon solid acid catalyst decreased somewhat in the first two recycles due to the leaching of polycyclic aromatic hydrocarbon containing –SO3H groups and then it remained constant in the following reuse.
基金financial support from the National Natural Science Foundation of China(grant No.21706085)Subsidized Project for Postgraduates’Innovative Fund in Scientific Research of Huaqiao Universitythe Foundation of Key Laboratory of Pulp and Paper Science and Technology of Ministry of Education/Shandong Province of China(grant No.KF201804)。
文摘Two kinds of mesoporous carbon solid acids(LDMCE-SO3H and LDMCS-SO3H)were successfully prepared using masson pine alkali lignin as carbon source by evaporation-induced self-assembly(EISA)and salt-induced selfassembly(SISA)followed by sulfonation,respectively.In terms of preparation process,SISA(self-assembly in water and preparation time of 2 days)is greener and simpler than EISA(self-assembly in ethanol and preparation time of 7 days).The prepared LDMCE-SO3H and LDMCS-SO3H exhibit obvious differences in structural characteristics such as pore channel structure,specific surface area,mesopore volume and the density of-SO3H groups.Furthermore,the catalytic performances of LDMCE-SO3H and LDMCS-SO3H were investigated in the hydrolysis of microcrystalline cellulose in water,and the glucose yields of 48.99%and 54.42%were obtained under the corresponding optimal reaction conditions.More importantly,the glucose yields still reached 28.85%and 30.35%after five runs,and restored to 39.02%and 45.98%through catalysts regeneration,respectively,demonstrating that LDMCE-SO3H and LDMCS-SO3H have excellent recyclability and regenerability.
基金the National Key Project ofScientific and Technical SupportingPrograms Funded by the Ministry of Science & Technology of China (No.2006BAE03B06)the Shanghai International Cooperation of Science and Technology Project (No.06SR07101).
文摘The synthesis of 2, 4-diisopropyl-5,5-dimethy1- 1.3-dioxane through the acetalization of isobutyraldehyde with 2, 2, 4-trimethy1-1,3-pentanediol (TMPD) catalyzed by the novel carbon based acid was first carried out. High conversion (≥98%) and specific selectivity were obtained using the novel carbon based acid, which kept high activity after it was reused 5 times. Moreover. the catalyst could be used to catalyze the acetalization and ketalization of different aldehydes and ketones with superior yield. The yield of several products was over 90%. The novel heterogeneous catalyst has the distinct advantages of high activity, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the success of the green process greatly.
基金supported by National Natural Science Foundation of China(Nos.20975056,21275082 and 81102411)Natural Science Foundation of Shandong(Nos. ZR2011BZ004,ZR2011BQ005)+2 种基金JSPS and NSFC under the Japan-China Scientific Cooperation Program(No.21111140014)State Key Laboratory of Analytical Chemistry for Life Science(No. SKLACLS1110)the National Key Basic Research Development Program of China(973 Special Preliminary Study Plan,No. 2012CB722705)
文摘In this work, a new sample pretreatment method prior to HPLC separations was developed for the determination of auxins in plant samples, Owing to its large surface area and high adsorption capacity, multi-walled carbon nanotube (MWCNT) was chosen as the adsorbent for the extraction of auxins from plant samples. In this study, two important auxins were selected as model analytes, namely indole-3- butyric acid (IBA) and 1-naphthylacetic acid (NAA). They could be extracted and concentrated due to their π-π stacking interactions with MWCNT. Then HPLC-UV was introduced to detect IBA and NAA after sample pretreatment. Factors that may affect the enrichment efficiency were investigated and optimized. Comparative studies showed that MWCNT was superior to CI 8 for the extraction of the two analytes. Validation experiments showed that the optimized method had good linearity (0.9998 and 0.9960), high recovery (81.4%-85.4%), and low detection limits (0.0030 mg/L and 0.0012 mg/L). The results indicated that the novel method had advantages of convenience, good sensitivity, high efficiency, and it was feasible for the determination of auxins in plant samples.