Catalytic cracking in presence of an aromatic addition

Fluidized bed catalytic cracking of vacuum gas oil fractions in the presence of extract from phenol purification of heavy lubricating oil fraction as an aromatic addition was investigated. Results show that, at the optimum concentration of the addition, coke formation on the catalyst decreases by 50 to 70% while the content of olefinic hydrocarbons in gasoline decreases, with a corresponding increase in the content of paraffin/naphthene hydrocarbons. The yield of gasoline increases, while its octane number increases by about two units.     

Depolymerization of Turkish lignites. 2. Effect of phenol concentration in a closed system

A lignite (C, 66.9 wt%) was depolymerized, using sulphuric acid as a catalyst, in a closed system in which the phenol/coal ratio was varied from 1.5 to 10. The products were separated by solvent extraction and silica gel chromatography. The i.r. and n.m.r. spectra, and the molecular weight of the products were measured. In the experiments with a phenol/coal ration of 10, complete depolymerization of the coal was seen provided the temperature of depolymerization was at least 210 °C. The products generally contained disubstituted aromatic structures connected by methylene bridges, it was found that as the phenol/coal ratio was increased there was a decrease in the number of methylene bridges connecting the aromatic structures. The molecular weights of the straight-chain pentane and benzene-soluble material were lower than the molecular weights of similar fractions in depolymerization experiments carried out in open systems. A method for the structural analysis of straight-chain pentane and benzene-soluble material based on i.r., ¹H n.m.r. and molecular weight measurements is suggested.     

Cooperative effect induced by the mixing of Na-ZSM-5 and Pd/H3PW12O40/SiO2 in the selective catalytic reduction of NO with aromatic hydrocarbons

Pd was loaded on the dispersed H₃PW₁₂O₄₀ (HPW) over the SiO₂ surface, and the catalyst was applied to the selective reduction of NO with aromatic hydrocarbons. The catalyst exhibited high activity in the NO reduction when branched aromatic hydrocarbons, such as toluene and xylene, were used as reductants. The catalytic activity of Pd/HPW/SiO₂ was improved remarkably by physically mixing it with Na-ZSM-5. From the temperature programmed desorption (TPD) of toluene and the analysis of the products, it was inferred that the activity was enhanced when Pd/HPW/SiO₂ and Na-ZSM-5 were mixed. In other words, aromatic hydrocarbons were partially oxidized to yield oxygenated hydrocarbons, e.g., benzaldehyde and phthalic anhydride, over Pd/Na-ZSM-5; in this reaction, a part of Pd migrated from Pd/HPW/SiO₂ to Na-ZSM-5 during the course of the physical mixing procedure. Subsequently, the oxygenated hydrocarbons reacted with NO entrapped with HPW over Pd to yield N₂.     

Wet oxidation of wastewater containing hydrocarbons by novel supported Pd catalysts

Pd catalysts supported on TiO₂, ZrO₂, ZSM-5, MCM-41 and activated carbon were used in catalytic wet oxidation of hydrocarbons such as phenol, m-cresol and m-xylene. It was found that the Pd/TiO₂ catalyst was highly effective in the wet oxidation of hydrocarbon. The activities of catalysts with various hydrocarbon species, catalyst support, oxidation state of catalyst performed in a 3-phase slurry reactor show that reaction on Pd surface is more favorable than that in aqueous phase and that the active site is oxidized Pd in catalytic wet air oxidation of hydrocarbons. Based on the experimental results, a plausible reaction mechanism of wet oxidation of hydrocarbons catalyzed over Pd/TiO₂ catalyst was proposed. This catalyst is superior to other oxide catalysts because it suppressed the formation of hardly-degradable organic intermediates and polymer.     

2,2’-亚甲基双(6-环己基-4-甲基苯酚)的水相合成研究

本文以自制的2-环己基对甲酚为原料,在酸性催化剂条件下,以水为溶剂,与甲醛水溶液缩合反应合成了抗氧剂2,2’-亚甲基双(6-环己基-4-甲基苯酚)又称抗氧剂ZKF。本工艺采用廉价的甲醛水溶液代替国内外多数工艺中采用的甲缩醛或多聚甲醛,并以水为溶剂代替了有机溶剂,水溶液可循环使用5次,实现了清洁生产并降低了产品成本。产品收率为90.2%,产品纯度99.3%。     

Fe-Zn共改性ZSM-5催化作用下生物质快速热解特性研究

选取木屑和花生壳作为原料进行生物质热解，研究有机产物分布，催化剂使用Fe、Zn两种金属元素进行改性。通过X射线衍射（XRD）、扫描电镜（SEM）、傅里叶红外（FT-IR）、比表面积测试（BET）对Fe-Zn改性的ZSM-5进行分析。使用闪速裂解-气质联用仪（PY-GC/MS）对原料进行热解，探究生物质催化热解的产物分布变化。催化剂的使用使得芳烃类产物产率获得较大提升，在木屑热解中，Fe负载的分子筛催化获得了酚类的最高产率，比ZSM-5催化热解产率提升18.30%。金属改性催化剂在花生壳热解中，大幅提升了芳烃类产物产率，其中Zn负载催化剂芳烃类产物产率最高，Zn负载催化热解比直接热解的酚类产率降低了18.92%。Zn负载催化获得了最低的酮类产率，与直接热解相比酮类产率降低19.74%，显示出较强的脱羟基效果。此外Zn负载催化和Fe-Zn双金属负载催化在花生壳热解中都大幅降低了酸类产物产率，与直接热解相比酸类产率分别降低了30.46%、36.71%。     

Ionic Liquid-Based Molecular Oxygen Oxidation of Eucalyptus Kraft Lignin to Obtain a Suite of Monomeric Aromatic By-Products

The oxidative degradation of eucalyptus kraft lignin as a function of an oxygen-enriched ionic liquid (IL) medium was investigated as part of a fundamental study to examine its capacity to degrade lignin into a suite of potentially valuable by-products relative to a standard sodium hydroxide solution (control). The variables of temperature, oxygen pressure, reaction time, and catalyst on the aromatic monomer products were controlled, whereas it was found that the yields of various aromatic monomer products were significantly improved when ionic liquid was used as the solvent instead of sodium hydroxide solution. These yields increased more substantially when a mixture of ionic liquid and sodium hydroxide was exploited as the reaction solvent. A quantity of 105.3 mg/g aromatic monomer products can be obtained at a temperature of 150°C, reaction time of two hours, and oxygen pressure of 6 MPa using CuO as the catalyst. In addition to the formation of aromatic monomer products, there were a number of other fascinating functional group and chemical linkage changes observed in the lignin macromolecule within the IL-based reaction system.     

Catalytic Deoxygenation of C18 Fatty Acids Over Mesoporous Pd/C Catalyst for Synthesis of Biofuels

Deoxygenation was systematically investigated using either stearic, oleic or linoleic acids as a feedstock at 300 °C under 1 vol% hydrogen in argon over a mesoporous Pd/C (Sibunit) catalyst producing one less carbon containing, diesel-like hydrocarbons. The results revealed that catalyst activity and selectivity increased with less unsaturated feedstock. The main products in the case of stearic acid were desired C17 hydrocarbons, whereas the amounts of C17 aromatic compounds increased in case of oleic and linoleic acids. Catalyst deactivation was relatively prominent in linoleic acid deoxygenation giving only 3% conversion of fatty acids in 330 min. The deactivation originated from the formation of C17 aromatic compounds and fatty acid dimers, which was confirmed by size exclusion chromatographic analysis. The latter compounds were formed via Diels?CAlder reaction.     

溶胶凝胶法制备超细镍基催化剂及在溶剂油精制中的应用

用溶胶凝胶法制备了一种超细镍基催化剂,应用氮气物理吸附法(BET)、程序升温还原TPR和等离子发射等方法对催化剂进行了表征,并在自制的固定床反应器上对溶剂油精制进行了应用研究。结果表明,经该催化剂精制的溶剂油芳烃含量远远低于国内外同类产品。     

The fluorescence of suspensions of powdered coals

The fluorescence spectra of aqueous suspensions of powders of polystyrene, two phenol–formaldehyde resites and a humic acid have been shown to be similar to the fluorescence spectra of their solutions in polar solvents. Fluorescence occurs both from individual aromatic structures and from excimers caged in the solid powders. Accordingly, the synchronous fluorescence (Δ=20 nm) of aqueous suspensions of a range of powdered coals showed the majority of the aromatic structures present in the coals to consist of substituted mono- and bi-aromatic rings. Excimers and exciplexes were also present. Excitation spectra of the aqueous suspensions confirm this interpretation. The fluorescence of powdered coals suspended in chloroform arises from the material extracted into the solvent. Accordingly the fluorescence spectra are dominated by the excimers and exciplexes formed in the solution; this fluorescence is enhanced by energy transfer from the smaller aromatic systems.     

Catalytic Treatment of Vacuum Carburizing Off Gas

The aim of this investigation was to find a suitable procedure for the treatment of higher polycyclic aromatic hydrocarbons, produced during vacuum carburizing of steel. In a lab scale apparatus the carburizing gas acetylene was pyrolyzed and the generated gases converted in a downstream catalytic bed reactor. The results show that it is possible to remove the higher pyrolysis products from the off gas. A complete conversion of the off gases into carbon and hydrogen was achieved with a Ni/SiO₂/SiC‐catalyst at temperatures ? 520 °C. Coke, formed during the conversion of the hydrocarbons on the catalyst, is removed from the catalyst by burning it off. The functionality of the catalyst is investigated for both the reduced and the non‐reduced state, whereby the non‐reduced catalyst deactivates faster.     

煤液化油中低级酚生成的影响因素研究

为了探究反应温度、反应压力、催化剂添加量以及供氢溶剂对褐煤直接液化油中低级酚生成的影响以及低级酚生成的机理,利用模型化合物邻苄基苯酚在煤直接液化条件下进行加氢反应。实验结果表明:邻苄基苯酚在液化条件下主要发生桥键断裂反应生成低级酚,苯环不易被加氢饱和。温度升高对促进邻苄基苯酚桥键断裂有利;压力升高则不利于其桥键断裂;铁系催化剂添加量的增加会促进桥键断裂;供氢溶剂四氢萘相比十氢萘会抑制低级酚的生成。邻苄基苯酚加氢液化的产物以苯酚与甲苯为主,邻甲酚与苯相对较少。     

The influence of catalyst regeneration on the composition of zeolite-upgraded biomass pyrolysis oils

The composition of oils derived from the on-line, low pressure zeolite upgrading of biomass pyrolysis oils from a fluidized bed pyrolysis unit have been investigated in relation to the regeneration of the zeolite catalyst. The catalyst used was H-ZSM-5 zeolite. The gases were analysed by packed column gas chromatography. The composition of the oils before catalysis and after catalyst upgrading were analysed by liquid chromatography fractionation, followed by coupled gas chromatography—mass spectrometry of each fraction. In particular, the aromatic and oxygenated aromatic species were identified and quantified. In addition, the oils were analysed for their elemental composition and molecular weight range using size exclusion chromatography. Before catalysis the biomass pyrolysis oil was highly oxygenated but after catalysis a highly aromatic oil was formed with high concentrations of monocyclic aromatic hydrocarbons. In addition, significant concentrations of polycyclic aromatic hydrocarbons (PAH) were formed. Regeneration of the zeolite catalyst showed that continued regeneration reduced the effectiveness of the catalyst in converting biomass pyrolysis oils to an aromatic product. Elemental analysis of the upgraded oils showed an increase in the oxygen content of the oil with increasing regeneration of the catalyst. The molecular weight range of the oils was found to decrease markedly after catalysis, but continued regeneration of the catalyst increased the molecular weight range of the upgraded oils. Detailed analysis of the uncatalysed oils showed they contained low concentrations of aromatic and PAH species which markedly increased in concentration after catalysis. The overall effect of increasing catalyst regeneration was a decrease in the concentration of aromatic hydrocarbons and PAH. Also as the catalyst was regenerated, the number of methyl groups on the parent single ring aromatic compound or PAH increased. The oxygenated aromatic species in the oil before catalysis were mainly, phenols and benzenediols and their alkylated homologues. After catalysis some of the oxygenated species were reduced and some increased in concentration. A dual mechanistic route is suggested for the formation of aromatics and PAH during the catalytic upgrading of biomass pyrolysis oils: (1) the formation of low-molecular-weight hydrocarbons on the catalyst which then undergo aromatization reactions to produce aromatic hydrocarbons and PAH; (2) deoxygenation of oxygenated compounds found in the non-phenolic fraction of the pyrolysis oils which directly form aromatic compounds.     

温控型水-有机两相苯酚催化加氢反应

根据反应物苯酚在室温下微溶于水，但是在反应温度下能与水互溶，而产物环己酮或环己醇微溶于水的特点，提出利用绿色溶剂水代替挥发性有机物，实现在水溶剂条件下的苯酚催化加氢反应。在反应过程中，反应速率不受传质限制，而且反应结束后可以通过简单的相分离技术实现产物与水的分离，分离得到的水可以循环使用，过程无废液排放，环境友好。更重要的是，由于催化剂在水相和在有机溶剂相中对反应物和产物具有不同的吸脱附性能，如Raney Ni催化剂在水相中比在醇类等有机溶剂相中具有更强的氢气吸附能力，这为提高催化加氢反应的活性和改变目标产物的选择性提供了一种有效的途径。     

烟煤固体热载体低温快速热解实验研究

以连续式热解装置为实验平台,藁城和府谷煤为原料,石英砂为热载体,考察了460~520℃范围内热解所得气、液产物收率、组成和性质的变化规律. 结果表明,在考察的温度范围内,提高热解温度,热解气、液产物收率增加,液体产物收率最高可达12%左右. 热解温度对热解产物中不凝气组成影响显著,热解煤气热值高达25 MJ/Nm3以上. 焦油组分中酚衍生物含量最高,稠环烃、芳香烃、链烃组分的含量也较高,酚含量随热解温度增高有所降低,而芳烃含量则显著提高. 根据实验结果提出了酚-芳烃转化的可能路径.     

Titanium deposited from TiCl4 on amorphous silica and silicalite-1 as catalyst in aromatic hydroxylation reactions

Titanium deposited from TiCl₄ on crystalline or amorphous SiO₂ catalyses the hydroxylation of phenol with aqueous H₂O₂. The amorphous silica-supported titanium shows a high rate of hydrogen peroxide conversion, however with a low selectivity towards aromatic hydroxylation products. A silicalite-supported titanium catalyst exhibits an efficiency towards hydroxylation products, based on hydrogen peroxide conversion, that is equal to that of titanium-silicalite-1 (TS-1), however with a lower activity.     

Photodegradation of polycyclic aromatic hydrocarbons in fossil fuels catalysed by supported TiO2

This paper describes the photodegradation behavior of polycyclic aromatic hydrocarbons present in different types of fossil fuels (commercial diesel, Arabian light crude, heavy fuel oil from the Prestige oil spill and coal from an abandoned coal dump) suspended in artificial seawater or ultrapure water, under irradiation in a stirred photochemical reactor for 14 days. The reactor was continuously fed with air from a compressor at a constant rate of 6 NL h⁻¹, and thin films of TiO₂ (anatase) supported on pyrex glass raschig rings were used as catalyst. Dark control samples were carried out simultaneously for all the experiments, and both phases, aqueous and organic, were analyzed by gas chromatography–mass spectrometry in the experimental and dark control samples, allowing to calculate a photodegradation ratio. The polycyclic aromatic hydrocarbons reached a high degree of photodegradation in the water-soluble fraction of the samples, but the organic fractions remained almost unaffected in most of the experiments. Some photodegradation products have been also identified in the aqueous and organic fractions of the samples.     

Potassium and nickel doped β-Mo2C catalysts for mixed alcohols synthesis via syngas

Potassium and nickel doped β-Mo₂C catalysts were prepared and their performances of CO hydrogenation were investigated. The main products over β-Mo₂C catalyst were hydrocarbons, and only few alcohols were obtained. The potassium promoter resulted in remarkable selectivity shift from hydrocarbons to alcohols over β-Mo₂C. Moreover, it was found that the potassium promoter enhanced the ability of chain propagation of β-Mo₂C catalyst and resulted in a higher selectivity to C₂₊OH. When doped by potassium and nickel, β-Mo₂C catalyst showed high activity and selectivity for mixed alcohols synthesis, the Ni promoter further enhanced the whole chain propagation to produce alcohols especially for the step of C₁OH–C₂OH. From the XPS analysis, it had been proved that the formation of higher alcohols might be attributable to the presence of Mo^IV species, whereas the formation of hydrocarbons was closely associated with the presence of Mo^II species on the surface of the catalysts.     

低温煤焦油中特定芳烃组分的选择性分离

以研究低温煤焦油中特定芳烃组分的选择性分离为目标, 通过预处理分离酚类化合物和富集特定芳烃组分, 采用多元溶剂萃取方法选择性分离芳烃和非芳烃组分, 采用Hansen溶度参数理论进行多元溶剂的设计和萃取条件的优化。结果表明, 溶剂对原料焦油的选择性随Hansen溶度参数“距离”(R_a)增加而增大, 萃取能力则相反。研究得到的多元萃取剂是含水量为体积分数6%的N,N-二甲基甲酰胺溶液, 优化萃取条件是温度25℃、剂/油比6:1。萃余物经多次萃取进一步分离芳烃组分, 萃出物经甲酰胺多次萃取以分离出杂环化合物和极性组分。芳烃组分在最终分离产物中的质量分数为94%, 其总萃取收率为95%。另外非芳烃化合物、杂环化合物和其他极性组分也在本过程中得到了有效富集。     

催化裂化油浆糠醛精制工艺研究

以大庆石化总厂催化裂化油浆为原料,糠醛作为分离溶剂,可以有效地将油浆的可裂化组分与稠环芳烃分离。实验考察了抽提温度,质量剂油比和停留时间对精制效果的影响。结果表明,在抽提温度为60℃,溶剂比为2:1,停留时间30min时,油浆的分离效果较好。产品中精制油饱和烃的含量高达80%,具有良好的催化裂化性能,抽出油可作为芳香型橡胶填充油的调和组分。