环烷酸盐对稠油多环芳烃富存CO水热变换新生氢作用的影响

以蒽为稠油多环芳烃模型化合物,在反应温度400℃、CO初压2 MPa、CO/H_2O(物质的量比)为1∶2.5条件下,用高压反应釜考察了不同反应时间下反应体系中环烷酸盐对蒽富存CO水热变换新生氢的影响,并对环烷酸镍和环烷酸铁复配盐在反应过程中的作用进行了分析。结果表明:环烷酸铁和环烷酸镍对CO水热变换和蒽加氢反应均有催化作用,但环烷酸镍更有利于促进CO水热变换反应,而环烷酸铁对蒽加氢反应的催化作用更强;环烷酸盐单独作用时,当加入环烷酸盐中镍质量分数为0.08%、铁质量分数为0.05%时,各自对蒽加氢反应的催化效果最好;环烷酸铁与环烷酸镍复配对CO水热变换和蒽加氢反应可起到协同催化作用,能够促进CO水热变换反应和蒽加氢反应。研究表明,CO水热变换与蒽加氢反应之间存在正协同效应,二者相互促进。     

稠油多环芳烃对CO水热变换新生氢富存作用的研究

以蒽为稠油多环芳烃模型化合物,在反应温度400 ℃,CO初压2 MPa,CO/H2O(摩尔比)1:2.5的条件下,用高压反应釜内考察了不同反应时间下反应体系中环烷酸盐对蒽富存CO水热变换新生氢的影响,并对环烷酸镍和环烷酸铁复配盐在反应过程中的作用进行了分析。结果表明：环烷酸铁和环烷酸镍对CO水热变换和蒽加氢反应均有催化作用,但环烷酸镍更有利于促进CO水热变换,而环烷酸铁对蒽加氢反应的催化作用更强;环烷酸盐单独作用,当加入的环烷酸盐中镍含量（w）为0.08%、铁含量（w）为0.05%时,各自的蒽加氢效果最好;环烷酸铁与环烷酸镍复配对CO水热变换和蒽加氢反应可起到协同催化作用,复配盐的作用在于促进CO水热变换反应和蒽加氢反应。研究表明,CO水热变换与蒽加氢反应之间存在正协同效应,二者相互促进。     

不锈钢黑磷化后石墨烯封闭工艺及性能研究

通过正交实验确定黑色磷化液的配方为:马日夫盐30 g/L,Zn(H_2PO_4)2·2H_2O 20 g/L,Zn(NO_3)_2·6H_2O 8 g/L,Mn(NO_3)_2 10 g/L,Ni(NO_3)_2·6H_2O 6 g/L,CuSO_4溶液(适量),稳定剂2.8 g/L,稀土碳酸盐0.6 g/L,磷化时间35 min。讨论石墨烯的添加量对封闭工艺的影响。通过电化学工作站进行测试,确定当石墨烯添加量为0.5 g/L时,石墨烯封闭工艺最好。     

完全甲烷化催化剂失活原因分析

以Al_2O_3为载体,Ni(NO_3)_2·6H_2O,La(NO_3)_3·6H_2O为浸渍溶液,制备了完全甲烷化催化剂及相应的改性催化剂。以合成气为原料,研究了完全甲烷化催化剂失活的原因与机理。结果表明:催化剂失活是H2S中毒、CO中毒、催化剂积炭和烧结几种原因共同作用的结果。为了减少催化剂失活,合成气中H_2S体积分数应控制在1×10-6以下,甲烷化反应温度不低于300℃;在合成气中加入体积分数为10. 8%的水蒸气可抑制积炭。催化剂中引入MgO,La_2O_3对于提高催化剂的稳定性和抗烧结能力具有显著效果。     

镍铬类水滑石的制备及其催化性能

采用低过饱和共沉淀法,以Ni(NO_3)_2·6H_2O和Cr(NO_3)_3·9H_2O为原料,NaOH为沉淀剂制备了晶相单一、结晶度高的镍铬类水滑石化合物,并利用XRD,IR及TG-DTA对其结构进行了表征。测定了加入沉淀剂NaOH后,不同n(Ni):n(Cr)混合盐溶液中混合盐体系pH值的变化情况,探讨了不同因素对镍铬类水滑石制备的影响。将制备的催化剂应用于尿素与丙二醇反应生成碳酸丙烯酯反应中,在反应温度170℃,n (尿素):n(1,2-丙二醇)=1:1,反应时间180 min,催化剂用量0.2 g条件下,尿素转化率可达100%,碳酸丙烯酯产率达90%。     

YCCo_3(CO)_9金属簇络合物的合成与醛化性能(Ⅱ)

本文报导了常压合成金属簇络合物的新方法,合成了BrCCo_3(CO)_9和β-C_(10)H_7GCo_3(CO)_9。考察了这两种簇络合物对己烯-1的醛化活性,并和HCCo_3(CO)_9、ClCCo_3(CO)_9、PhCCo_3(CO)_9及C_2H_5O_2CCCo_3(CO)_9等簇络合物的醛化活性进行了比较。结果表明,这两种簇络合物亦是新型的烯烃醛化催化剂。在较缓和的条件下(反应温度140℃,压力40公斤/厘米~2,反应4小时),己烯-1转化率达98％以上,醇醛选择性95％以上。讨论了YCCo_3(CO)_9金属簇络合物作为醛化催化剂的特点。     

希夫碱配合物RE_3L_6(NO_3)_6(H_2O)_2的合成与光谱性质

以4-氨基-1,2,4-三氮唑与对羟基苯甲醛为原料,在冰醋酸催化下合成了配体4-氨基-1,2,4-三氮唑缩对羟基苯甲醛(L)。然后利用4-氨基-1,2,4-三氮唑缩对羟基苯甲醛(L)与过渡金属硝酸盐[RE(NO_3)_2·xH_2O(RE=Cu,Co,Zn,Cd;x=3～6)]在无水乙醇中反应,制得固态配合物RE_3L_6(NO_3)6(H_2O)_2。通过元素分析、红外光谱、紫外光谱、荧光光谱等手段对合成的配体及配合物进行了表征。结果表明,RE_3L_6(NO_3)_6(H_2O)_2与RE(Ⅱ)发生配位作用的基团是配体中三氮唑环上的氮原子。     

Photo-Fenton和Photo-Fenton-like试剂对萘羟基化反应的影响

实验以H_2O_2,乙腈、Fe(NO_3)_3·9H_2O、FeSO_4·7H_2O,为试剂,以自制光催化反应器制备了萘酚。研究了Photo-Fenton和Photo-Fenton-like反应体系中萘的羟基化反应,考察了Fe~(2+)、Fe~(3+)浓度、H_2O_2浓度、反应时间等因素对两种反应体系的影响。对于Photo-Fenton反应体系中,在[Fe~(2+)]=1.5mmol/L、[H_2O_2]=0.8 mol/L条件下,萘的转化率达43%,1-萘酚的收率为2.8%。对于Photo-Fenton-like反应体系,在[Fe~(3+)]=4.5 mmol/L,[H_2O_2]=0.2 mol/L条件下,萘的转化率为17%,1-萘酚的收率达4.6%;同条件下[H_2O_2]提高至1.0 mol/L时,萘的转化率可达90%,但1-萘酚的收率却有所下降。     

乙酰丙酮镍催化乙炔一步合成丙烯酸丁酯工艺的研究

在乙炔羰基化合成丙烯酸丁酯(BA)的一系列非卤素镍盐的筛选中,发现Ni(acac)_2具有较高的催化活性。在Ni(acac)_2中添加不同乙酰丙酮类盐,发现加入一定量Naacac·H_2O后反应活性明显提高。考察了催化剂配比,正丁醇用量,乙炔和CO初始分压,反应温度和时间对反应的影响。由实验结果可知,最优的工艺条件为:n(Naacac·H_2O)∶n(Ni(acac)_2)=1∶3、反应温度230℃、初始压力4.7MPa,n(乙炔)∶n(正丁醇)∶n(CO)=1∶1.4∶2.1,反应时间1h。该反应条件下丙烯酸丁酯收率为64.4%,选择性为99.2%。此催化剂体系对设备腐蚀性较低,工业前景良好。     

CO选择性氧化催化剂Au/Fe_2O_3的研究

采用共沉淀法制备了Au/Fe2O3催化剂,并用于富氢气体中CO的选择性氧化反应。研究结果表明,Au/Fe2O3催化剂对于富氢气体中CO的选择性氧化反应具有较高的低温活性和较高的选择性。40～80℃时对CO的转化率在94%以上,选择性在65%以上。在80℃时连续反应300h,催化剂表现出很好的稳定性。XRD、XPS和BET分析结果表明,催化剂的性能与单质Au的粒径有关,粒径越小,催化活性越高。     

Promoted catalysts for hydrogenation of bicyclic aromatic hydrocarbons obtained in situ from molybdenum and tungsten carbonyls

Promoted Мo and W catalysts have been prepared in situ via thermal decomposition of precursors, oil-soluble salts Mo(CO)₆, W(CO)₆, С°C₁₆H₃₀O₄, and NiC₁₆H₃₀O₄. TiO₂, Al₂O₃, and ZrO(NO₃)₂ · 6H₂O have been used as the acidic additives. Also, Mo and W unsupported sulfide catalysts have been prepared in the presence of elemental sulfur as the sulfiding agent. The catalysts have been characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The activity of the catalysts prepared in situ has been evaluated in the hydrogenation reaction of bicyclic aromatic hydrocarbons by the example of model mixtures of 10% solutions of naphthalenes (unsubstituted naphthalene, 1- and 2-methylnaphthalenes, and 1,5- and 2,3-dimethylnaphthalenes) in n-hexadecane. The effect of the precursor/acidic oxide ratio on the activity of the formed catalyst has been found. Hydrogenation of bicyclic aromatic hydrocarbons has been conducted at a hydrogen pressure of 2 and 5 MPa and a temperature of 380 and 400°C for 2 h. Hydrogenation of the unsubstituted aromatic ring has been preferable due to the absence of steric hindrances. The degree of conversion of n-hexadecane under the reaction conditions has been 1.5–7.5% depending on the reaction temperature. It has been found that the activity of the sulfided catalyst in the conversion of 1- and 2-methylnaphthalenes is inferior to the activity of the unsulfided analogue, while partial replacement of TiO₂ by Al₂O₃ results in a decrease in the conversion of the substrates as opposed to the unsulfided catalysts, in which the use of nanocrystalline Al₂O₃ promotes an increase in the conversion.     

Preparation of Ni—W aromatic hydrocarbon hydrogenation catalysts by breaking reverse emulsions or suspensions of a precursor in hydrocarbon feedstock

Reverse emulsions (hydrocarbon feedstock)/(aqueous precursor solution) for synthesizing aromatic hydrocarbon hydrogenation catalysts have been prepared using the water-soluble salts (NH₄)₂WS₄ and Ni(NO₃)₂ · 6 H₂O as precursors. It has been found that the optimum stabilizer for the emulsions is the nonionic surfactant SPAN-80. The resulting emulsions exhibit low catalytic activity in the hydrogenation of aromatic hydrocarbons; it has been shown that the activity of the systems in hydrodearomatization reactions is adversely affected by the presence of water. A procedure for preparing suspensions of solid precursor particles in a hydrocarbon feedstock by the removal of water from the resulting reverse emulsions has been developed. The catalytic activity of the resulting suspensions in the hydrogenation of aromatic hydrocarbons has been studied using naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene as examples. It has been shown that the catalytic activity of the suspensions is higher than that of the reverse emulsions of the same composition. It has been found that the feedstock should be subjected to additional sulfurization with elemental sulfur for further sulfiding the surface of the nickel—tungsten catalyst. The W: Ni molar ratio of 1 : 1 has been found to be optimum.     

The ignition and combustion characteristics of Al/Ni(IO3)2·4H2O nanothermites

ABSTRACT

Nickel iodate tetrahydrate (Ni(IO₃)₂·4H₂O) particles with different morphology and size were synthesized by precipitation method (PM) and electrospray precipitation method (EPM). The electrospray was used in chemical precipitation to synthesize nanoscale metal iodate particles with a narrow size distribution. The thermal decomposition mechanism of Ni(IO₃)₂·4H₂O at different heating rates, ignition, and combustion of Al/Ni(IO₃)₂·4H₂O nanothermites was studied by thermogravimetry–differential scanning calorimetry–mass spectrometry, T-jump and time-of-flight mass spectrometry, T-jump equipped with high-speed camera, and combustion cell test. The Al/Ni(IO₃)₂·4H₂O prepared by EPM had a lower ignition temperature (587 ± 14°C) and a shorter burn time (159 µs). The ignition processes of Al/Ni(IO₃)₂·4H₂O nanothermites prepared by EPM and PM were solid–solid and gas–liquid reactions, respectively. The rate-determining step of their combustion processes was the burning of aluminum powder and the decomposition of Ni(IO₃)₂· 4H₂O, respectively.     

Effect of methanol, ethanol, and formaldehyde addition on the steam conversion of methane in the presence of nickel catalysts of various porous structure

The effect of CH₂O, CH₃OH, and C₂H₅OH on the methane conversion and the CO, CO₂, and coke yield in the methane steam conversion on commercial nickel catalysts for steam reforming C 11-9-09 (12.8 wt % Ni/α-Al₂O₃) and hydrogenation (54.0 wt % Ni/kieselguhr) was studied at a temperature of 750°C and an H₂O:CH₄ ratio of 1.5–2.0. The action of these compounds was studied both individually and for their joint presence in the methane-steam mixture. Their effect on the reaction depends on the pore structure of the catalyst. Using the catalyst C 11-9-09 as an example, it was found that the introduction of formaldehyde into steam suppressed the methane conversion into C_s and high-boiling-point carbon compounds and gave the desired products with a yield close to the equilibrium value. When all three additives were present in the steam, ethanol was responsible for the formation of C_s.     

Effect of small concentrations of water on ethylbenzene oxidation with molecular oxygen catalyzed by iron(II, III) acetylacetonate complexes with 18-crown-6

The catalytic effects of small amounts of water (～10^?3 mol/l) added to the ethylbenzene oxidation reaction with molecular oxygen catalyzed by the system {Fe(III)(acac)₃ + 18-crown-6 (18C6)} were revealed. An increase in the reaction rate was observed, and the direction of the oxidation reaction changed. In the presence of the catalytic system {Fe(III)(acac)₃ (5.0 × 10^?3 mol/l) + 18C6 (5.0 × 10^?3 mol/l) + H₂O (3.7 × 10^?3 mol/l}, the main product at early stages of ethylbenzene oxidation is acetophenone, rather than α-phenylethyl hydroperoxide produced in the case of catalysis by the system {Fe(III)(acac)₃ (5.0 × 10^?3 mol/l) + 18C6 (5.0 × 10^?3 mol/l)} (in the absence of water admixture). A method is proposed to evaluate the activity of forming in situ (Fe(II)(acac)₂) _x (18C6) _y (H₂O) _n complexes at microstages of chain initiation (O₂ activation) and propagation (Ct+RO ₂ ^· ) involving the catalyst, which determine the rate and selectivity of oxidation. A possible “dioxygenase-like” mechanism of conversion of iron complexes with 18C6 in the presence of activating H₂O admixtures is discussed.     

Influence of Anderson and Keggin heteropoly compounds as precursors of oxide phases in hydrotreating catalysts on their performance

Unpromoted and nickel-promoted catalysts were synthesized on the basis of the Anderson heteropoly compounds (NH₄)_{6 ? x} [X ^x (OH)₆Mo₆O₁₈] · nH₂O, where heteroatom X is Cr(III), Mn(II), Fe(II), Ni(II), Co(II), Cu(II), Zn(II), or Ga(III), and their activity in the thiophene hydrogenolysis reaction and hydrofining of diesel fraction was examined. It was shown that the most active hydrotreating catalysts under the test conditions in a flow unit were the samples with X = Ni, Mn, or Zn. The catalysts synthesized from the Keggin heteropoly compounds H₄[SiMo₁₂O₄₀] · 17H₂O, H₃[PMo₁₂O₄₀] · 19H₂O, H₃[PVMo₁₁O₄₀] · nH₂O, and (NH₄) _x [V(MoO₃)₁₂] · nH₂O were tested in the hydrofining of light coker gas oil. The maximum activity was displayed by the catalysts prepared on the basis of the vanadium-containing heteropoly compounds H₃[PVMo₁₁O₄₀] · nH₂O and (NH₄) _x [V(MoO₃)₁₂] · nH₂O.     

Zinc-Substituted Polyoxometalate for Oxidative Desulfurization of Dibenzothiophene

Abstract

An oxidative desulfurization process for model compound has been studied using Na₁₂[WZn₃(H₂O)₂(ZnW₉O₃₄)₂] · 46H₂O as catalyst and 30 wt% aqueous hydrogen peroxide as the oxidizing agent. The effects of the reaction time, the reaction temperature, the amount of the oxidizing agent and the catalyst on the removal of dibenzothiophene (DBT) were investigated. The oxidated resultant was removed by extraction with polar solvent to reduce the sulfur level in the model compound. The maximum removal of DBT was up to 70%.     

Effect of process conditions on Fischer–Tropsch synthesis product selectivity over an industrial iron-based catalyst in slurry reactor

The authors present the application of the statistical model in CO hydrogenation to CH₄, C₂-C₄ and C₅₊ over industrial iron-based catalyst (100 Fe/5 Cu/4.2 K/25 SiO₂) in a 1-L stirred tank slurry reactor. The effect of different reaction conditions, including temperatures (T = 493, 513 and 533 K), pressures (P = 0.8, 1.5, 2.25, and 2.5 MPa), synthesis gas feed molar ratios (H₂/CO = 0.67 and 2), and gas space velocity (GSV) from 0.52 to 23.5 Ndm³/g-Fe/h on selectivity investigated via a statistical models. The proposed selectivity model is very useful in the oil, gas, and petrochemical industries and can be used for interpretation of experimental data, comparison of performance of different reactor conditions, and reactor modeling and simulation studies. Furthermore, interaction between operating parameters such as pressure, temperature, H₂/CO, and GSV was investigated in selectivity models. A CUBIC polynomial was successfully fitted to the experimental data. It was concluded that C₅₊ selectivity shifts to higher with increasing total pressure (H₂/CO) ratio and decreasing temperature. Decreased H₂/CO ratio and temperature and increasing in the reactor pressure cause CH₄ formation decrease. Temperature and pressure fluctuations vary product distribution. As it is observed, the insignificant term in C₂-C₄ selectivity is pressure. With the models obtained from regression we can reach to the optimum condition for favorite products such as C₂-C₄ or C₅₊. So that optimization must be done to illustrate the optimum conditions. It was obtained that the maximum amount of C₅₊ and C₂-C₄ and minimum amount of methane achieved in T = 528.97 K, P = 1.23 bar, H₂/CO = 2, and GSV = 23.49 Ndm³/g-Fe/h.     

低温高活性甲醇水蒸气重整制氢催化剂的研究

研究了Cu/La2 O3 /ZrO2 基催化剂在甲醇水蒸气重整制氢反应中的反应活性、选择性及其还原行为 ,并考察了反应条件 (温度、水醇比、液体空速 )对活性和选择性的影响。结果表明 :Cu/La2 O3 /ZrO2 基催化剂在甲醇水蒸气重整制氢反应过程中显示出较好的反应活性和高的选择性。在常压、反应温度 190～ 2 40℃、液体空速为 1 0～ 3 0h-1和水醇摩比为 1～ 3 0的反应条件下 ,甲醇转化率随着反应温度的升高而增大 ,重整产物中CO含量有所增加 ;提高水醇比有利于提高甲醇转化率 ,同时可降低重整产物中CO含量 ;甲醇转化率随着液体空速的增加有所降低 ,而重整产物中CO含量也有所降低。在Cu/La2 O3 /ZrO2 基催化剂上 ,甲醇重整反应和水 汽变换反应有可能同时进行