氧气液相催化氧化孔雀绿隐色体的环境友好工艺研究

研究了催化剂种类及用量、循环氧化剂四氯苯醌的用量、溶剂、底物初始浓度、醋酸用量、反应温度和反应时间对氧气液相氧化孔雀绿隐色体的影响。发现在乙醇介质中以金属络合物为催化剂、氧气为氧化剂、催化剂用量为底物质量的 3 %、四氯苯醌用量为底物质量的 0 91%、隐色体初始浓度为 3 3mol/L、醋酸用量与溶剂总量的体积比为 1∶6、于 5 0℃下反应 10h ,可以获得76 72 %的产品收率。工艺过程由于使用了价廉易得、无污染的氧气为氧化剂 ,因而对环境友好。氧化产物的结构经过核磁共振谱得以确认。     

Fe-V-HMS催化剂的制备及其氧化脱硫性能研究

以十二胺(DDA)为模板剂,正硅酸乙酯为硅源,采用一步合成法合成了双金属负载型Fe-V-HMS介孔分子筛催化剂,并通过FT-IR、XRD等手段对其进行了表征分析。以叔丁基过氧化氢为氧化剂,对Fe-V-HMS催化氧化脱除以正庚烷为溶剂的模拟油中的二苯并噻吩进行了活性评价。采用单因素法考察了催化剂用量、反应温度、反应时间、氧化剂用量对氧化脱硫效果的影响。结果表明:FeV-HMS催化剂可有效催化氧化脱除模拟油中的二苯并噻吩,在反应温度60℃、反应时间30 min、氧化剂用量0.03 m L、催化剂用量0.03 g、模拟油5 m L的条件下,脱硫率达到97.41%。介孔分子筛催化剂具有良好的化学性质和热稳定性,在催化领域有着很好的应用前景。     

SiO_2-CuO复合氧化物催化氧化脱除苯并噻吩性能的研究

采用溶胶-凝胶法制备了SiO_2-CuO复合氧化物,通过X射线衍射(XRD)、扫描电镜(SEM)、N2吸附(BET)等表征手段对试样进行了表征。以石油醚为溶剂,配制500 mg/L(以S计)的苯并噻吩(BT)模拟原料油,以SiO_2-CuO复合氧化物为催化剂,考察了催化剂用量、氧化剂H_2O_2用量、溶剂用量、反应温度、反应时间等因素对脱硫率的影响。研究结果表明,SiO_2-CuO复合氧化物呈片状,粒径在0.5~7.0μm,复合氧化物中的Cu以CuO形式存在,其比表面积低于SiO_2。在原料油10 m L,催化剂0.05 g,氧化剂H2O20.1 m L,乙腈与原料油体积比0.3∶1,反应温度65℃,反应时间60 min等最佳反应条件下,BT脱除率达到64.6%。     

MoO_3/介孔Al_2O_3-H_2O_2体系用于柴油催化氧化脱硫

用等体积浸渍法制备的MoO3/介孔Al2O3做催化剂,以双氧水做氧化剂,对柴油进行氧化脱硫的研究,考察了MoO3负载量、氧化剂用量、催化剂用量、氧化反应温度和时间对柴油脱硫效果的影响。结果表明,在考察的范围内,最佳催化氧化条件是MoO3负载量为20%、催化剂用量为1.0%、氧化剂H2O2与柴油中硫的摩尔比为12,氧化温度为60℃反应30 min,并且在此条件下柴油的脱硫率为68.4%。     

双氧水作用下的芳香基烯烃氧化

芳香基烯烃是重要的石油化工原料,其氧化产物是常用的有机中间体。为进行芳烯氧化反应的研究,先以苯乙烯为原料,着重讨论了催化剂、氧化剂用量和溶剂用量对氧化反应的影响。在0.52 g(5.0 mmol)苯乙烯、0.02 g催化剂水滑石、2.6 m L溶剂乙腈、2.4 m L氧化剂双氧水、70℃下反应10 h,苯乙烯转化率为93%,苯乙酮产率为87%。并且在相同的反应条件下,其他芳香基烯烃也可氧化生成相应的酮类。实验结果表明,由双氧水、水滑石、乙腈构成的反应体系能很好地进行苯乙烯等芳香基烯烃的氧化。     

微波辅助湿式催化氧化处理腈纶废水的研究

将微波与湿式催化氧化技术相结合,以硫酸改性纳米氧化铈为催化剂,H2O2为氧化剂,降解腈纶废水。研究了催化剂和氧化剂的用量、反应时间、反应温度等因素对有机物去除率的影响,确定了最佳反应条件为50 m L腈纶废水(COD 635 mg/L)投加0.25 g酸化纳米Ce O2催化剂和0.3 m L 6%的H2O2,室温下搅拌3 h,微波辐射140℃下反应60 min,COD平均去除率达到89.7%。     

焦磷酸铜催化氧化环己烷合成环己酮的研究

采用沉淀法制备了磷酸铜、焦磷酸铜和三聚磷酸铜催化剂。以环己烷氧化为探针反应,过氧化氢为氧化剂,考察了催化剂、溶剂种类、溶剂用量、催化剂用量、氧化剂用量、反应温度以及反应时间的影响,并提出了氧化反应机理。结果表明：焦磷酸铜的催化活性最高,在乙腈用量10 mL,环己烷用量8 mmol,焦磷酸铜用量0.0300 g,w（H2O2）=30%的双氧水用量3.00 mL,反应温度65 ℃的条件下,反应10 h后,环己烷的转化率为54.1%,醇酮的收率分别为21.3%和32.8%。     

Co-β-SBA-15催化氧化脱硫性能研究

采用浸渍法制备Co-β-SBA-15催化剂,通过XRD、BET和FT-IR等对其进行表征与分析,结果发现,该催化剂具有良好的稳定性。将其应用于模拟柴油的催化氧化脱硫反应中,在模拟柴油用量为30 m L、氧化剂用量为4 m L、萃取剂用量为30 m L、催化剂质量为0. 5 g、反应温度为70℃、反应时间为2 h的最佳工艺条件下,模拟柴油的脱硫率达到97. 71%。     

Co-VPO催化甲苯液相H_2O_2氧化制苯甲醛

以Co-VPO为催化剂,对常压下甲苯液相H2O2氧化制备苯甲醛进行了研究。考察了催化剂用量、反应温度、反应时间、H2O2用量、溶剂用量等因素对反应的影响。结果表明:Co-VPO复合催化剂对甲苯液相氧化反应具有优良的催化性能,在催化剂用量为0.4 g,助催化剂NaBr用量为0.2 g,反应温度为90℃,反应时间为4 h,H2O2用量为12 mL,溶剂用量为15 mL的条件下,甲苯的转化率可达19.8%,苯甲醛的选择性为60.4%。对催化剂进行了固体紫外表征,并对反应机理做了初步探讨。     

焦磷酸铜催化氧化环己烷

采用沉淀法制备了磷酸铜、焦磷酸铜和三聚磷酸铜催化剂,并采用X射线衍射仪对催化剂进行了表征。以环己烷氧化为探针反应,过氧化氢为氧化剂,考察了催化剂、溶剂、氧化剂、反应温度以及反应时间对氧化效果的影响。结果表明,非均相焦磷酸铜催化剂的催化活性最高,在乙腈用量10 mL,环己烷用量8 mmol,焦磷酸铜用量0.03 g,w(H2O2)=30%的双氧水用量3.0 mL,反应温度65℃的条件下,反应10 h后,环己烷的转化率为54.1%,环己醇和环己酮(简称醇酮,以下同)的收率分别为21.3%和32.8%。     

蔗糖在DMF-[BMIm]Cl溶剂中催化制备5-HMF

研究了在N,N-二甲基甲酰胺(DMF)-离子液体[BMIm]Cl混合溶剂中将蔗糖高效转化为5-羟甲基糠醛(5-HMF)的反应。运用紫外-可见分光光度计对水解液中5-HMF进行定量分析并计算其收率。考察了CrCl₃·6H₂O、AlCl₃·6H₂O、SnCl₄·5H₂O、FeCl₃、CoCl₂·6H₂O、ZnCl₂、CuCl₂·2H₂O、CaCl₂ 8种催化剂对反应的催化效果,结果表明AlCl₃·6H₂O催化效果最为明显。以AlCl₃·6H₂O为催化剂研究了不同反应条件如时间、温度、溶剂中DMF-[BMIm]Cl质量比、催化剂AlCl₃·6H₂O的用量对5-HMF收率的影响,得到的最佳条件为以0.5mmol蔗糖为反应物,0.4mmol AlCl₃·6H₂O为催化剂,反应时间2h,反应温度120℃,5g质量比为85:15的DMF-[BMIm]Cl混合溶剂,此条件下5-HMF收率最高可达63.4%。研究表明,DMF-[BMIm]Cl混合溶剂体系对蔗糖转化为5-HMF有一定的促进效果,在此溶剂体系中以AlCl₃·6H₂O为催化剂时可以得到较高的5-HMF产率。     

Kinetics of CO and H2 oxidation over CuO-CeO2 catalyst in H2 mixtures with CO2 and H2O

The kinetics of CO and H₂ oxidation over a CuO-CeO₂ catalyst were simultaneously investigated under reaction conditions of preferential CO oxidation (PROX) in hydrogen-rich mixtures with CO₂ and H₂O. An integral packed-bed tubular reactor was used to produce kinetic data for power-law kinetics for both CO and H₂ oxidations. The experimental results showed that the CO oxidation rate was essentially independent of H₂ and O₂ concentrations, while the H₂ oxidation rate was practically independent of CO and O₂ concentrations. In the CO oxidation, the reaction orders were 0.91, −0.37 and −0.62 with respect to the partial pressure of CO, CO₂ and H₂O, respectively. In the H₂ oxidation, the orders were 1.0, −0.48 and −0.69 with respect to the partial pressure of H₂, CO₂ and H₂O, respectively. The activation energies of the CO oxidation and the H₂ oxidation were 94.4 and 142 kJ/mol, respectively. The rate expressions of both oxidations were able to predict the performance of the PROX reactor with accuracy. The independence between the CO and the H₂ oxidation suggested different sites for CO and H₂ adsorption on the CuO-CeO₂ catalyst. Based on the results, we proposed a new reaction model for the preferential CO oxidation. The model assumes that CO adsorbs selectively on the Cu⁺ sites; H₂ dissociates and adsorbs on the Cu⁰ sites; the adsorbed species migrates to the interface between the copper components and the ceria support, and reacts there with the oxygen supplied by the ceria support; and the oxygen deficiency on the support is replenished by the oxygen in the reaction mixture.     

Study of Ag/La0.6Sr0.4MnO3 catalysts for complete oxidation of methanol and ethanol at low concentrations

Ag-modified La_0.6Sr_0.4MnO₃-based catalysts with the perovskite-type structure were prepared by using a citric acid sol–gel method, and their catalytic performance for complete oxidation of methanol and ethanol was evaluated and compared with that of the γ-Al₂O₃-supported catalysts, Ag/γ-Al₂O₃, Pt/γ-Al₂O₃, and Pd/γ-Al₂O₃. The results showed that the Ag-modified La_0.6Sr_0.4MnO₃-based catalysts with the perovskite-type structure displayed the activity significantly higher than that of the supported precious metal catalysts, 0.1%Pd/γ-Al₂O₃ and 0.1%Pt/γ-Al₂O₃ in the temperature range of 370–573 K. Over a 6%Ag/20%La_0.6Sr_0.4MnO₃/γ-Al₂O₃ catalyst, the T₉₅ temperature for methanol oxidation can be as low as 413 K. Even at such low reaction temperature, there were little HCHO and CO detected in the reaction exit-gas. However, for the 0.1%Pd/γ-Al₂O₃ and 0.1%Pt/γ-Al₂O₃ catalysts, the HCHO content in the reaction exit-gas reached 200 and 630 ppm at their T₉₅ temperatures. Over a 6%Ag/La_0.6Sr_0.4MnO₃ catalyst, the T₉₅ temperature for ethanol oxidation can be as low as 453 K, with a corresponding content of CH₃CHO in the exit-gas at 782 ppm; when ethanol oxidation is performed at 493 K, the content of acetaldehyde in the exit-gas can be below 1 ppm. Characterization of the catalysts by X-ray diffraction (XRD), TEM, XPS, laser Raman spectra (LRS), hydrogen temperature-programmed reduction (H₂-TPR) and oxygen temperature-programmed desorption (O₂-TPD) methods revealed that both the surface and the bulk phase of the perovskite La_0.6Sr_0.4MnO₃ played important roles in the catalytic oxidation of the alcohols, and that γ-Al₂O₃ as the bottom carrier could be beneficial in creating a large surface area of catalyst. Moreover, a small amount of Ag⁺ doped onto the surface of La_0.6Sr_0.4MnO₃ was able to partially occupy the positions of La³⁺ and Sr²⁺ due to their similar ionic radii, and thus, became stabilized by the perovskite lattice, which would be in favor of preventing the aggregation of the Ag species on the surface and enhancing the stability of the catalyst. On the other hand, modification of the Ag⁺ to the surface of La_0.6Sr_0.4MnO₃ resulted in an increase in relative content of the surface O₂²⁻/O⁻ species highly reactive toward the alcohols and aldehydes as well as CO. Besides, solution of low-valence metal oxides SrO and Ag₂O with proper amounts in the lattice of the trivalent metal perovskite-type oxide LaMnO₃ would also lead to an increase in the content of the reducible Mnⁿ⁺ and the formation of anionic vacancies, which would be favorable for the adsorption-activation of oxygen on the functioning catalyst and the transport of the lattice and surface oxygen species. All these factors would contribute to the pronounced improvement of the catalyst performance.     

Preparation,Characterization of Dawson-type Heteropoly Acid Cerium (III) Salt and Its Catalytic Performance on the Synthesis of n-Butyl Acetate

A novel cerium (III) salt of Dawson type tungstophosphoric acid (Ce₂P₂W₁₈O₆₂·16H₂O) was prepared by doping cerous nitrate in H₆P₂W₁₈O₆₂·13H₂O powder and characterized by thermogravimetry and differential thermal analyses (TG/DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), pyridine infrared spectroscopy (Py-IR) and scanning electron microscopy (SEM). Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol. The effects of various parameters such as molar ratio of n-butanol to acetic acid, reaction temperature, reaction time, and catalyst amount have been studied by single factor experiment. The results show that Ce₂P₂W₁₈O₆₂·16H₂O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate. The optimum synthetic conditions were determined as follows:molar ratio of n-butanol to acetic acid at 2.0:1.0, mass of the catalyst being 1.44% of the total reaction mixture, reaction temperature of 120 ℃ and reaction time of 150 min. Under above conditions, the conversion of acetic acid was above 97.8％. The selectivity of n-butyl acetate based on acetic acid was, in all cases, nearly 100%. The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction. It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products. Compared with using sulfuric acid as catalyst, the present procedure with Ce₂P₂W₁₈O₆₂·16H₂O is a green productive technology due to simple process, higher yield, catalyst recycling and no corrosion for the production facilities.     

强化除磷BAF处理石化二级出水

为强化曝气生物滤池(BAF)的除磷效果,以石化二级出水为处理对象,研究了投加FeSO₄·7H₂O对BAF除磷性能的强化作用并对投量进行了优化,同时分析了FeSO₄·7H₂O投加对BAF除碳、脱氮和生物膜活性的影响。结果表明:投加少量FeSO₄·7H₂O(3~15 mg·L^-1)能有效强化BAF的除磷性能;BAF除磷的效果随FeSO₄·7H₂O投加量的增加而提高,但在投量高于9 mg·L^-1时增加趋势逐渐变缓,当FeSO₄·7H₂O的投加量为9 mg·L^-1时,TP的去除率达到57.0%以上,而同期平行运行的BAF除磷效率为7.1%。BAF中少量投加FeSO₄·7H₂O对COD的去除没有不良影响,COD的去除率比对比装置平均提高了5.4%左右,对相对分子质量较大的有机物去除明显。FeSO₄·7H₂O投加量低于12mg·L^-1时对 的去除没有不良影响,高于15 mg·L^-1时由于生物膜中微生物活性的下降 去除率有所降低。投加FeSO₄·7H₂O对TN的去除影响甚微。Fe²⁺的投加使得BAF中附着微生物的量有所降低,但在12 mg·L^-1以下时不会造成大的影响,FeSO₄·7H₂O投量在3~9 mg·L^-1时BAF中生物膜的脱氢酶活性和比好氧呼吸速率有所增加,可弥补生物量降低的影响,因此BAF的运行状况未受到影响。     

纳米氧化镁的制备及降解性能

以六水氯化镁和氨水为主要原料制备纳米氧化镁,通过正交试验考察了Mg²⁺浓度、分散剂PEG-400用量、反应温度、陈化时间和缓冲剂冰醋酸的用量5个因素对晶粒粒径的影响,确定了纳米氧化镁的最佳工艺参数：缓冲剂冰醋酸用量为0.015 mol,Mg²⁺浓度为0.4 mol/L, 分散剂用量为5 mL,反应温度为60 ℃,反应时间为0 h,煅烧温度为550 ℃,煅烧时间为2 h。分析了单因素对纳米氧化镁晶粒的影响。选用对氧磷测试纳米氧化镁的吸附降解性,1 μL的对氧磷在5 min内被0.4 g氧化镁降解吸附了99.19%。1 g纳米氧化镁可降解吸附对氧磷194.9 mg。     

沉淀方式对沉淀法制备Co_3O_4催化N_2O直接分解性能的影响

以Co(NO_3)_2·6H_2O为钴源,K_2CO_3为沉淀剂,采用沉淀法制备Co_3O_4催化剂,用于催化N_2O直接分解反应。利用N_2~-物理吸附、XRD、FT-IR、TEM、TPR和ICP等对其进行表征,考察沉淀方式对Co_3O_4催化剂结构及其催化性能的影响。结果表明,沉淀方式对制备的Co_3O_4催化剂织构性质、物相组成和晶粒尺寸等影响不大,但显著影响其K残留量和还原性能,进而决定催化剂直接催化分解N_2O的催化性能。反加法制得的催化剂中K残留量为1.43%,明显高于正加法,同时催化剂中Co~(3+)较正加法更易还原,因而表现出更高的催化性能。在空速10 000 h~(-1)和N_2O体积分数0.1%的条件下,反加法制备的催化剂可在280℃催化N_2O完全分解,较正加法低20℃。     

Combined effect of H2O and SO2 on V2O5/AC catalysts for NO reduction with ammonia at lower temperatures

Combined effect of H₂O and SO₂ on V₂O₅/AC the activity of catalyst for selective catalytic reduction (SCR) of NO with NH₃ at lower temperatures was studied. In the absence of SO₂, H₂O inhibits the catalytic activity, which may be attributed to competitive adsorption of H₂O and reactants (NO and/or NH₃). Although SO₂ promotes the SCR activity of the V₂O₅/AC catalyst in the absence of H₂O, it speeds the deactivation of the catalyst in the presence of H₂O. The dual effect of SO₂ is attributed to the SO₄²⁻ formed on the catalyst surface, which stays as ammonium-sulfate salts on the catalyst surface. In the absence of H₂O, a small amount of ammonium-sulfate salts deposits on the surface of the catalyst, which promote the SCR activity; in the presence of H₂O, however, the deposition rate of ammonium-sulfate salts is much greater, which results in blocking of the catalyst pores and deactivates the catalyst. Decreasing V₂O₅ loading decreases the deactivation rate of the catalyst. The catalyst can be used stably at a space velocity of 9000 h⁻¹ and temperature of 250 °C.     

Activity enhancement of SnO2-doped Ga2O3–Al2O3 catalysts by coexisting H2O for the selective reduction of NO with propene

Catalytic reduction of NO by propene in the presence of oxygen was studied over SnO₂-doped Ga₂O₃–Al₂O₃ prepared by sol–gel method. Although SnO₂-doped Ga₂O₃–Al₂O₃ gave lower NO conversion than Ga₂O₃–Al₂O₃ in the absence of H₂O, the activity was enhanced considerably by the presence of H₂O and much higher than that of Ga₂O₃–Al₂O₃. The presence of SnO₂ and Ga₂O₃–Al₂O₃ species having intimate Ga–O–Al bondings was found to be essential for the promotional effect of H₂O. The promotional effect of H₂O was interpreted by the following two reasons. The first one is the removal of carbonaceous materials deposited on the catalyst surface by H₂O. The other is the selective inhibition by H₂O of the reaction steps resulting in propene oxidation to CO_x without reducing NO.     

MnOx对Pt/CeZrO2催化剂在水汽和CO2环境下CO氧化的影响

以CeZrO₂固溶体为载体,发现MnO_x的添加能促进Pt/CeZrO₂催化剂的CO氧化性能,并研究了MnO_x含量对催化剂CO氧化活性及抗H₂O和CO₂性能的影响。结果表明,随着MnO_x含量增加,催化剂活性呈现先升高后降低的趋势,在MnO_x含量为0.5%（质量分数）时活性最佳。MnO_x的添加降低了Pt颗粒尺寸并影响催化剂还原性能从而促进反应活性。水汽和CO₂对Pt/CeZrO₂催化剂的CO氧化活性有抑制作用,而MnO_x的加入能显著提高催化剂的抗水汽和CO₂的能力。反应动力学结果表明,在Pt/CeZrO₂催化剂上,反应气中引入H₂O和CO₂后,CO的反应级数有明显升高,说明H₂O和CO₂在催化剂表面与CO竞争吸附,导致CO反应活性下降;而在Pt/MnO_x/CeZrO₂催化剂上,CO的反应级数略有升高,说明MnO_x的添加能有效抑制H₂O和CO₂与CO的竞争吸附,从而改善了催化剂的抗H₂O和CO₂性能。